Merge branches 'no-rebases', 'arch-avr32', 'arch-blackfin', 'arch-cris', 'arch-h8300', 'arch-m32r', 'arch-mn10300', 'arch-score', 'arch-sh' and 'arch-powerpc' into for-next

arch/arm64/Kconfig

···
 	select GENERIC_IOMAP
 	select GENERIC_IRQ_PROBE
 	select GENERIC_IRQ_SHOW
+	select GENERIC_KERNEL_EXECVE
+	select GENERIC_KERNEL_THREAD
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_TIME_VSYSCALL
 	select HARDIRQS_SW_RESEND

arch/arm64/include/asm/processor.h

···
 extern struct task_struct *cpu_switch_to(struct task_struct *prev,
 					 struct task_struct *next);
 
-/*
- * Create a new kernel thread
- */
-extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-
 #define task_pt_regs(p) \
 	((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1)
 

arch/arm64/include/asm/syscalls.h

···
 /*
  * System call wrappers implemented in kernel/entry.S.
  */
-asmlinkage long sys_execve_wrapper(const char __user *filename,
-				   const char __user *const __user *argv,
-				   const char __user *const __user *envp);
-asmlinkage long sys_clone_wrapper(unsigned long clone_flags,
-				  unsigned long newsp,
-				  void __user *parent_tid,
-				  unsigned long tls_val,
-				  void __user *child_tid);
 asmlinkage long sys_rt_sigreturn_wrapper(void);
 asmlinkage long sys_sigaltstack_wrapper(const stack_t __user *uss,
 					stack_t __user *uoss);
+
+/*
+ * AArch64 sys_clone implementation has a different prototype than the generic
+ * one (additional TLS value argument).
+ */
+#define sys_clone	sys_clone
 
 #include <asm-generic/syscalls.h>
 

arch/arm64/include/asm/unistd.h

···
 #define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
 #define __ARCH_WANT_COMPAT_SYS_SENDFILE
 #endif
+#define __ARCH_WANT_SYS_EXECVE
 #include <uapi/asm/unistd.h>

arch/arm64/include/asm/unistd32.h

···
 
 __SYSCALL(0,   sys_restart_syscall)
 __SYSCALL(1,   sys_exit)
-__SYSCALL(2,   compat_sys_fork_wrapper)
+__SYSCALL(2,   compat_sys_fork)
 __SYSCALL(3,   sys_read)
 __SYSCALL(4,   sys_write)
 __SYSCALL(5,   compat_sys_open)
···
 __SYSCALL(8,   sys_creat)
 __SYSCALL(9,   sys_link)
 __SYSCALL(10,  sys_unlink)
-__SYSCALL(11,  compat_sys_execve_wrapper)
+__SYSCALL(11,  compat_sys_execve)
 __SYSCALL(12,  sys_chdir)
 __SYSCALL(13,  sys_ni_syscall)			/* 13 was sys_time */
 __SYSCALL(14,  sys_mknod)
···
 __SYSCALL(117, sys_ni_syscall)			/* 117 was sys_ipc */
 __SYSCALL(118, sys_fsync)
 __SYSCALL(119, compat_sys_sigreturn_wrapper)
-__SYSCALL(120, compat_sys_clone_wrapper)
+__SYSCALL(120, sys_clone)
 __SYSCALL(121, sys_setdomainname)
 __SYSCALL(122, sys_newuname)
 __SYSCALL(123, sys_ni_syscall)			/* 123 was sys_modify_ldt */
···
 __SYSCALL(187, compat_sys_sendfile)
 __SYSCALL(188, sys_ni_syscall)			/* 188 reserved */
 __SYSCALL(189, sys_ni_syscall)			/* 189 reserved */
-__SYSCALL(190, compat_sys_vfork_wrapper)
+__SYSCALL(190, compat_sys_vfork)
 __SYSCALL(191, compat_sys_getrlimit)		/* SuS compliant getrlimit */
 __SYSCALL(192, sys_mmap_pgoff)
 __SYSCALL(193, compat_sys_truncate64_wrapper)

arch/arm64/kernel/entry.S

···
 /*
  * "slow" syscall return path.
  */
-ENTRY(ret_to_user)
+ret_to_user:
 	disable_irq				// disable interrupts
 	ldr	x1, [tsk, #TI_FLAGS]
 	and	x2, x1, #_TIF_WORK_MASK
···
  */
 ENTRY(ret_from_fork)
 	bl	schedule_tail
-	get_thread_info tsk
+	cbz	x19, 1f				// not a kernel thread
+	mov	x0, x20
+	blr	x19
+1:	get_thread_info tsk
 	b	ret_to_user
 ENDPROC(ret_from_fork)
 
···
 /*
  * Special system call wrappers.
  */
-ENTRY(sys_execve_wrapper)
-	mov	x3, sp
-	b	sys_execve
-ENDPROC(sys_execve_wrapper)
-
-ENTRY(sys_clone_wrapper)
-	mov	x5, sp
-	b	sys_clone
-ENDPROC(sys_clone_wrapper)
-
 ENTRY(sys_rt_sigreturn_wrapper)
 	mov	x0, sp
 	b	sys_rt_sigreturn

arch/arm64/kernel/process.c

···
 	struct pt_regs *childregs = task_pt_regs(p);
 	unsigned long tls = p->thread.tp_value;
 
-	*childregs = *regs;
-	childregs->regs[0] = 0;
-
-	if (is_compat_thread(task_thread_info(p)))
-		childregs->compat_sp = stack_start;
-	else {
-		/*
-		 * Read the current TLS pointer from tpidr_el0 as it may be
-		 * out-of-sync with the saved value.
-		 */
-		asm("mrs %0, tpidr_el0" : "=r" (tls));
-		childregs->sp = stack_start;
-	}
-
 	memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
-	p->thread.cpu_context.sp = (unsigned long)childregs;
-	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 
-	/* If a TLS pointer was passed to clone, use that for the new thread. */
-	if (clone_flags & CLONE_SETTLS)
-		tls = regs->regs[3];
+	if (likely(regs)) {
+		*childregs = *regs;
+		childregs->regs[0] = 0;
+		if (is_compat_thread(task_thread_info(p))) {
+			if (stack_start)
+				childregs->compat_sp = stack_start;
+		} else {
+			/*
+			 * Read the current TLS pointer from tpidr_el0 as it may be
+			 * out-of-sync with the saved value.
+			 */
+			asm("mrs %0, tpidr_el0" : "=r" (tls));
+			if (stack_start) {
+				/* 16-byte aligned stack mandatory on AArch64 */
+				if (stack_start & 15)
+					return -EINVAL;
+				childregs->sp = stack_start;
+			}
+		}
+		/*
+		 * If a TLS pointer was passed to clone (4th argument), use it
+		 * for the new thread.
+		 */
+		if (clone_flags & CLONE_SETTLS)
+			tls = regs->regs[3];
+	} else {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		childregs->pstate = PSR_MODE_EL1h;
+		p->thread.cpu_context.x19 = stack_start;
+		p->thread.cpu_context.x20 = stk_sz;
+	}
+	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
+	p->thread.cpu_context.sp = (unsigned long)childregs;
 	p->thread.tp_value = tls;
 
 	ptrace_hw_copy_thread(p);
···
 
 	return last;
 }
-
-/*
- * Shuffle the argument into the correct register before calling the
- * thread function.  x1 is the thread argument, x2 is the pointer to
- * the thread function, and x3 points to the exit function.
- */
-extern void kernel_thread_helper(void);
-asm(	".section .text\n"
-"	.align\n"
-"	.type	kernel_thread_helper, #function\n"
-"kernel_thread_helper:\n"
-"	mov	x0, x1\n"
-"	mov	x30, x3\n"
-"	br	x2\n"
-"	.size	kernel_thread_helper, . - kernel_thread_helper\n"
-"	.previous");
-
-#define kernel_thread_exit	do_exit
-
-/*
- * Create a kernel thread.
- */
-pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-
-	regs.regs[1] = (unsigned long)arg;
-	regs.regs[2] = (unsigned long)fn;
-	regs.regs[3] = (unsigned long)kernel_thread_exit;
-	regs.pc = (unsigned long)kernel_thread_helper;
-	regs.pstate = PSR_MODE_EL1h;
-
-	return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
 
 unsigned long get_wchan(struct task_struct *p)
 {

arch/arm64/kernel/sys.c

···
  */
 asmlinkage long sys_clone(unsigned long clone_flags, unsigned long newsp,
 			  int __user *parent_tidptr, unsigned long tls_val,
-			  int __user *child_tidptr, struct pt_regs *regs)
+			  int __user *child_tidptr)
 {
-	if (!newsp)
-		newsp = regs->sp;
-	/* 16-byte aligned stack mandatory on AArch64 */
-	if (newsp & 15)
-		return -EINVAL;
-	return do_fork(clone_flags, newsp, regs, 0, parent_tidptr, child_tidptr);
+	return do_fork(clone_flags, newsp, current_pt_regs(), 0,
+			parent_tidptr, child_tidptr);
 }
-
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage long sys_execve(const char __user *filenamei,
-			   const char __user *const __user *argv,
-			   const char __user *const __user *envp,
-			   struct pt_regs *regs)
-{
-	long error;
-	struct filename *filename;
-
-	filename = getname(filenamei);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-	error = do_execve(filename->name, argv, envp, regs);
-	putname(filename);
-out:
-	return error;
-}
-
-int kernel_execve(const char *filename,
-		  const char *const argv[],
-		  const char *const envp[])
-{
-	struct pt_regs regs;
-	int ret;
-
-	memset(&regs, 0, sizeof(struct pt_regs));
-	ret = do_execve(filename,
-			(const char __user *const __user *)argv,
-			(const char __user *const __user *)envp, &regs);
-	if (ret < 0)
-		goto out;
-
-	/*
-	 * Save argc to the register structure for userspace.
-	 */
-	regs.regs[0] = ret;
-
-	/*
-	 * We were successful.  We won't be returning to our caller, but
-	 * instead to user space by manipulating the kernel stack.
-	 */
-	asm(	"add	x0, %0, %1\n\t"
-		"mov	x1, %2\n\t"
-		"mov	x2, %3\n\t"
-		"bl	memmove\n\t"	/* copy regs to top of stack */
-		"mov	x27, #0\n\t"	/* not a syscall */
-		"mov	x28, %0\n\t"	/* thread structure */
-		"mov	sp, x0\n\t"	/* reposition stack pointer */
-		"b	ret_to_user"
-		:
-		: "r" (current_thread_info()),
-		  "Ir" (THREAD_START_SP - sizeof(regs)),
-		  "r" (&regs),
-		  "Ir" (sizeof(regs))
-		: "x0", "x1", "x2", "x27", "x28", "x30", "memory");
-
- out:
-	return ret;
-}
-EXPORT_SYMBOL(kernel_execve);
 
 asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
 			 unsigned long prot, unsigned long flags,
···
 /*
  * Wrappers to pass the pt_regs argument.
  */
-#define sys_execve		sys_execve_wrapper
-#define sys_clone		sys_clone_wrapper
 #define sys_rt_sigreturn	sys_rt_sigreturn_wrapper
 #define sys_sigaltstack		sys_sigaltstack_wrapper
 

arch/arm64/kernel/sys32.S

···
 /*
  * System call wrappers for the AArch32 compatibility layer.
  */
-compat_sys_fork_wrapper:
-	mov	x0, sp
-	b	compat_sys_fork
-ENDPROC(compat_sys_fork_wrapper)
-
-compat_sys_vfork_wrapper:
-	mov	x0, sp
-	b	compat_sys_vfork
-ENDPROC(compat_sys_vfork_wrapper)
-
-compat_sys_execve_wrapper:
-	mov	x3, sp
-	b	compat_sys_execve
-ENDPROC(compat_sys_execve_wrapper)
-
-compat_sys_clone_wrapper:
-	mov	x5, sp
-	b	compat_sys_clone
-ENDPROC(compat_sys_clone_wrapper)
 
 compat_sys_sigreturn_wrapper:
 	mov	x0, sp

arch/arm64/kernel/sys_compat.c

···
 #include <asm/cacheflush.h>
 #include <asm/unistd32.h>
 
-asmlinkage int compat_sys_fork(struct pt_regs *regs)
+asmlinkage int compat_sys_fork(void)
 {
-	return do_fork(SIGCHLD, regs->compat_sp, regs, 0, NULL, NULL);
+	return do_fork(SIGCHLD, 0, current_pt_regs(), 0, NULL, NULL);
 }
 
-asmlinkage int compat_sys_clone(unsigned long clone_flags, unsigned long newsp,
-			  int __user *parent_tidptr, int tls_val,
-			  int __user *child_tidptr, struct pt_regs *regs)
+asmlinkage int compat_sys_vfork(void)
 {
-	if (!newsp)
-		newsp = regs->compat_sp;
-
-	return do_fork(clone_flags, newsp, regs, 0, parent_tidptr, child_tidptr);
-}
-
-asmlinkage int compat_sys_vfork(struct pt_regs *regs)
-{
-	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->compat_sp,
-		       regs, 0, NULL, NULL);
-}
-
-asmlinkage int compat_sys_execve(const char __user *filenamei,
-				 compat_uptr_t argv, compat_uptr_t envp,
-				 struct pt_regs *regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname(filenamei);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-	error = compat_do_execve(filename->name, compat_ptr(argv),
-					compat_ptr(envp), regs);
-	putname(filename);
-out:
-	return error;
+	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 0,
+		       current_pt_regs(), 0, NULL, NULL);
 }
 
 asmlinkage int compat_sys_sched_rr_get_interval(compat_pid_t pid,

arch/avr32/Kconfig

···
 	select GENERIC_CLOCKEVENTS
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 	help
 	  AVR32 is a high-performance 32-bit RISC microprocessor core,
 	  designed for cost-sensitive embedded applications, with particular

arch/avr32/include/asm/processor.h

···
 /* Free all resources held by a thread */
 extern void release_thread(struct task_struct *);
 
-/* Create a kernel thread without removing it from tasklists */
-extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-
 /* Return saved PC of a blocked thread */
 #define thread_saved_pc(tsk)    ((tsk)->thread.cpu_context.pc)
 

arch/avr32/include/asm/unistd.h

···
 #define __ARCH_WANT_SYS_GETPGRP
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_SYS_EXECVE
 
 /*
  * "Conditional" syscalls

arch/avr32/kernel/Makefile

···
 obj-$(CONFIG_SUBARCH_AVR32B)	+= entry-avr32b.o
 obj-y				+= syscall_table.o syscall-stubs.o irq.o
 obj-y				+= setup.o traps.o ocd.o ptrace.o
-obj-y				+= signal.o sys_avr32.o process.o time.o
+obj-y				+= signal.o process.o time.o
 obj-y				+= switch_to.o cpu.o
 obj-$(CONFIG_MODULES)		+= module.o avr32_ksyms.o
 obj-$(CONFIG_KPROBES)		+= kprobes.o

arch/avr32/kernel/entry-avr32b.S

···
 	.global ret_from_fork
 ret_from_fork:
 	call   schedule_tail
+	mov	r12, 0
+	rjmp	syscall_return
 
-	/* check for syscall tracing */
-	get_thread_info r0
-	ld.w	r1, r0[TI_flags]
-	andl	r1, _TIF_ALLWORK_MASK, COH
-	brne	syscall_exit_work
-	rjmp    syscall_exit_cont
+	.global ret_from_kernel_thread
+ret_from_kernel_thread:
+	call   schedule_tail
+	mov	r12, r0
+	mov	lr, r2	/* syscall_return */
+	mov	pc, r1
 
 syscall_trace_enter:
 	pushm	r8-r12

arch/avr32/kernel/process.c

···
 }
 
 /*
- * PC is actually discarded when returning from a system call -- the
- * return address must be stored in LR. This function will make sure
- * LR points to do_exit before starting the thread.
- *
- * Also, when returning from fork(), r12 is 0, so we must copy the
- * argument as well.
- *
- *  r0 : The argument to the main thread function
- *  r1 : The address of do_exit
- *  r2 : The address of the main thread function
- */
-asmlinkage extern void kernel_thread_helper(void);
-__asm__("	.type	kernel_thread_helper, @function\n"
-	"kernel_thread_helper:\n"
-	"	mov	r12, r0\n"
-	"	mov	lr, r2\n"
-	"	mov	pc, r1\n"
-	"	.size	kernel_thread_helper, . - kernel_thread_helper");
-
-int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-
-	regs.r0 = (unsigned long)arg;
-	regs.r1 = (unsigned long)fn;
-	regs.r2 = (unsigned long)do_exit;
-	regs.lr = (unsigned long)kernel_thread_helper;
-	regs.pc = (unsigned long)kernel_thread_helper;
-	regs.sr = MODE_SUPERVISOR;
-
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
-		       0, &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/*
  * Free current thread data structures etc
  */
 void exit_thread(void)
···
 }
 
 asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
+asmlinkage void syscall_return(void);
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-		unsigned long unused,
+		unsigned long arg,
 		struct task_struct *p, struct pt_regs *regs)
 {
-	struct pt_regs *childregs;
+	struct pt_regs *childregs = task_pt_regs(p);
 
-	childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)task_stack_page(p))) - 1;
-	*childregs = *regs;
-
-	if (user_mode(regs))
+	if (unlikely(!regs)) {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		p->thread.cpu_context.r0 = arg;
+		p->thread.cpu_context.r1 = usp; /* fn */
+		p->thread.cpu_context.r2 = syscall_return;
+		p->thread.cpu_context.pc = (unsigned long)ret_from_kernel_thread;
+		childregs->sr = MODE_SUPERVISOR;
+	} else {
+		*childregs = *regs;
 		childregs->sp = usp;
-	else
-		childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
-
-	childregs->r12 = 0; /* Set return value for child */
+		childregs->r12 = 0; /* Set return value for child */
+		p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
+	}
 
 	p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
 	p->thread.cpu_context.ksp = (unsigned long)childregs;
-	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 
 	clear_tsk_thread_flag(p, TIF_DEBUG);
 	if ((clone_flags & CLONE_PTRACE) && test_thread_flag(TIF_DEBUG))
···
 	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs,
 		       0, NULL, NULL);
 }
-
-asmlinkage int sys_execve(const char __user *ufilename,
-			  const char __user *const __user *uargv,
-			  const char __user *const __user *uenvp,
-			  struct pt_regs *regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname(ufilename);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-
-	error = do_execve(filename->name, uargv, uenvp, regs);
-	putname(filename);
-
-out:
-	return error;
-}
-
 
 /*
  * This function is supposed to answer the question "who called

arch/avr32/kernel/sys_avr32.c

···
-/*
- * Copyright (C) 2004-2006 Atmel Corporation
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#include <linux/unistd.h>
-
-int kernel_execve(const char *file,
-		  const char *const *argv,
-		  const char *const *envp)
-{
-	register long scno asm("r8") = __NR_execve;
-	register long sc1 asm("r12") = (long)file;
-	register long sc2 asm("r11") = (long)argv;
-	register long sc3 asm("r10") = (long)envp;
-
-	asm volatile("scall"
-		     : "=r"(sc1)
-		     : "r"(scno), "0"(sc1), "r"(sc2), "r"(sc3)
-		     : "cc", "memory");
-	return sc1;
-}

arch/avr32/kernel/syscall-stubs.S

···
 	mov	r12, sp
 	rjmp	sys_vfork
 
-	.global	__sys_execve
-	.type	__sys_execve,@function
-__sys_execve:
-	mov	r9, sp
-	rjmp	sys_execve
-
 	.global	__sys_mmap2
 	.type	__sys_mmap2,@function
 __sys_mmap2:

arch/avr32/kernel/syscall_table.S

···
 	.long	sys_creat
 	.long	sys_link
 	.long	sys_unlink		/* 10 */
-	.long	__sys_execve
+	.long	sys_execve
 	.long	sys_chdir
 	.long	sys_time
 	.long	sys_mknod

arch/blackfin/Kconfig

···
 	select ARCH_USES_GETTIMEOFFSET if !GENERIC_CLOCKEVENTS
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 
 config GENERIC_CSUM
 	def_bool y

arch/blackfin/include/asm/processor.h

···
 {
 }
 
-extern int kernel_thread(int (*fn) (void *), void *arg, unsigned long flags);
-
 /*
  * Free current thread data structures etc..
  */

arch/blackfin/include/asm/unistd.h

···
 #define __ARCH_WANT_SYS_NICE
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_SYS_EXECVE
 
 /*
  * "Conditional" syscalls

arch/blackfin/kernel/entry.S

···
 	SP += -12;
 	pseudo_long_call _schedule_tail, p5;
 	SP += 12;
-	r0 = [sp + PT_IPEND];
-	cc = bittst(r0,1);
-	if cc jump .Lin_kernel;
+	p1 = [sp++];
+	r0 = [sp++];
+	cc = p1 == 0;
+	if cc jump .Lfork;
+	sp += -12;
+	call (p1);
+	sp += 12;
+.Lfork:
 	RESTORE_CONTEXT
 	rti;
-.Lin_kernel:
-	bitclr(r0,1);
-	[sp + PT_IPEND] = r0;
-	/* do a 'fake' RTI by jumping to [RETI]
-	 * to avoid clearing supervisor mode in child
-	 */
-	r0 = [sp + PT_PC];
-	[sp + PT_P0] = r0;
-
-	RESTORE_ALL_SYS
-	jump (p0);
 ENDPROC(_ret_from_fork)
 
 ENTRY(_sys_vfork)

arch/blackfin/kernel/process.c

···
 }
 
 /*
- * This gets run with P1 containing the
- * function to call, and R1 containing
- * the "args".  Note P0 is clobbered on the way here.
- */
-void kernel_thread_helper(void);
-__asm__(".section .text\n"
-	".align 4\n"
-	"_kernel_thread_helper:\n\t"
-	"\tsp += -12;\n\t"
-	"\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
-
-/*
- * Create a kernel thread.
- */
-pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-
-	regs.r1 = (unsigned long)arg;
-	regs.p1 = (unsigned long)fn;
-	regs.pc = (unsigned long)kernel_thread_helper;
-	regs.orig_p0 = -1;
-	/* Set bit 2 to tell ret_from_fork we should be returning to kernel
-	   mode.  */
-	regs.ipend = 0x8002;
-	__asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
-		       NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/*
  * Do necessary setup to start up a newly executed thread.
  *
  * pass the data segment into user programs if it exists,
···
 	    struct task_struct *p, struct pt_regs *regs)
 {
 	struct pt_regs *childregs;
+	unsigned long *v;
 
 	childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
-	*childregs = *regs;
-	childregs->r0 = 0;
+	v = ((unsigned long *)childregs) - 2;
+	if (unlikely(!regs)) {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		v[0] = usp;
+		v[1] = topstk;
+		childregs->orig_p0 = -1;
+		childregs->ipend = 0x8000;
+		__asm__ __volatile__("%0 = syscfg;":"=da"(childregs->syscfg):);
+		p->thread.usp = 0;
+	} else {
+		*childregs = *regs;
+		childregs->r0 = 0;
+		p->thread.usp = usp;
+		v[0] = v[1] = 0;
+	}
 
-	p->thread.usp = usp;
-	p->thread.ksp = (unsigned long)childregs;
+	p->thread.ksp = (unsigned long)v;
 	p->thread.pc = (unsigned long)ret_from_fork;
 
 	return 0;
-}
-
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage int sys_execve(const char __user *name,
-			  const char __user *const __user *argv,
-			  const char __user *const __user *envp)
-{
-	int error;
-	struct filename *filename;
-	struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
-
-	filename = getname(name);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		return error;
-	error = do_execve(filename->name, argv, envp, regs);
-	putname(filename);
-	return error;
 }
 
 unsigned long get_wchan(struct task_struct *p)

arch/blackfin/mach-common/entry.S

···
 	jump .Lsyscall_really_exit;
 ENDPROC(_trap)
 
-ENTRY(_kernel_execve)
-	link SIZEOF_PTREGS;
-	p0 = sp;
-	r3 = SIZEOF_PTREGS / 4;
-	r4 = 0(x);
-.Lclear_regs:
-	[p0++] = r4;
-	r3 += -1;
-	cc = r3 == 0;
-	if !cc jump .Lclear_regs (bp);
-
-	p0 = sp;
-	sp += -16;
-	[sp + 12] = p0;
-	pseudo_long_call _do_execve, p5;
-	SP += 16;
-	cc = r0 == 0;
-	if ! cc jump .Lexecve_failed;
-	/* Success.  Copy our temporary pt_regs to the top of the kernel
-	 * stack and do a normal exception return.
-	 */
-	r1 = sp;
-	r0 = (-KERNEL_STACK_SIZE) (x);
-	r1 = r1 & r0;
-	p2 = r1;
-	p3 = [p2];
-	r0 = KERNEL_STACK_SIZE - 4 (z);
-	p1 = r0;
-	p1 = p1 + p2;
-
-	p0 = fp;
-	r4 = [p0--];
-	r3 = SIZEOF_PTREGS / 4;
-.Lcopy_regs:
-	r4 = [p0--];
-	[p1--] = r4;
-	r3 += -1;
-	cc = r3 == 0;
-	if ! cc jump .Lcopy_regs (bp);
-
-	r0 = (KERNEL_STACK_SIZE - SIZEOF_PTREGS) (z);
-	p1 = r0;
-	p1 = p1 + p2;
-	sp = p1;
-	r0 = syscfg;
-	[SP + PT_SYSCFG] = r0;
-	[p3 + (TASK_THREAD + THREAD_KSP)] = sp;
-
-	RESTORE_CONTEXT;
-	rti;
-.Lexecve_failed:
-	unlink;
-	rts;
-ENDPROC(_kernel_execve)
-
 ENTRY(_system_call)
 	/* Store IPEND */
 	p2.l = lo(IPEND);

arch/c6x/Kconfig

···
 	select OF_EARLY_FLATTREE
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 	select MODULES_USE_ELF_RELA
 
 config MMU

arch/c6x/include/uapi/asm/unistd.h

···
  *   more details.
  */
 
-#define __ARCH_WANT_KERNEL_EXECVE
 #define __ARCH_WANT_SYS_EXECVE
 
 /* Use the standard ABI for syscalls. */

arch/c6x/kernel/entry.S

···
 0:
 	B	.S2	B10		   /* call fn */
 	LDW	.D2T1	*+SP(REGS_A1+8),A4 /* get arg */
-	MVKL	.S2	sys_exit,B11
-	MVKH	.S2	sys_exit,B11
-	ADDKPC	.S2	0f,B3,1
-0:
-	BNOP	.S2	B11,5	/* jump to sys_exit */
+	ADDKPC	.S2	ret_from_fork_2,B3,3
 ENDPROC(ret_from_kernel_thread)
-
-ENTRY(ret_from_kernel_execve)
-	GET_THREAD_INFO A12
-	BNOP	.S2	syscall_exit,4
-	ADD	.D2X	A4,-8,SP
-ENDPROC(ret_from_kernel_execve)
 
 	;;
 	;; These are the interrupt handlers, responsible for calling __do_IRQ()

arch/cris/Kconfig

···
 	select GENERIC_SMP_IDLE_THREAD if ETRAX_ARCH_V32
 	select GENERIC_CMOS_UPDATE
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 
 config HZ
 	int

arch/cris/arch-v10/kernel/entry.S

···
 	.globl system_call
 	.globl ret_from_intr
 	.globl ret_from_fork
+	.globl ret_from_kernel_thread
 	.globl resume
 	.globl multiple_interrupt
 	.globl hwbreakpoint
···
 	jsr schedule_tail
 	ba  ret_from_sys_call
 	nop
-		
+
+ret_from_kernel_thread:
+	jsr schedule_tail
+	move.d	$r2, $r10	; argument is here
+	jsr	$r1		; call the payload
+	moveq	0, $r9		; no syscall restarts, TYVM...
+	ba  ret_from_sys_call
+
 ret_from_intr:
 	;; check for resched if preemptive kernel or if we're going back to user-mode 
 	;; this test matches the user_regs(regs) macro
···
 	pop	$r0			; Restore r0. 
 	ba	do_sigtrap		; SIGTRAP the offending process. 
 	pop	$dccr			; Restore dccr in delay slot.
-
-	.global kernel_execve
-kernel_execve:
-	move.d __NR_execve, $r9
-	break 13
-	ret
-	nop
 
 	.data
 

arch/cris/arch-v10/kernel/process.c

···
 #include <arch/svinto.h>
 #include <linux/init.h>
 #include <arch/system.h>
+#include <asm/ptrace.h>
 
 #ifdef CONFIG_ETRAX_GPIO
 void etrax_gpio_wake_up_check(void); /* drivers/gpio.c */
···
 	return task_pt_regs(t)->irp;
 }
 
-static void kernel_thread_helper(void* dummy, int (*fn)(void *), void * arg)
-{
-  fn(arg);
-  do_exit(-1); /* Should never be called, return bad exit value */
-}
-
-/*
- * Create a kernel thread
- */
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-
-        /* Don't use r10 since that is set to 0 in copy_thread */
-	regs.r11 = (unsigned long)fn;
-	regs.r12 = (unsigned long)arg;
-	regs.irp = (unsigned long)kernel_thread_helper;
-	regs.dccr = 1 << I_DCCR_BITNR;
-
-	/* Ok, create the new process.. */
-        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
-}
-
 /* setup the child's kernel stack with a pt_regs and switch_stack on it.
  * it will be un-nested during _resume and _ret_from_sys_call when the
  * new thread is scheduled.
···
  *
  */
 asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-		unsigned long unused,
+		unsigned long arg,
 		struct task_struct *p, struct pt_regs *regs)
 {
-	struct pt_regs * childregs;
-	struct switch_stack *swstack;
+	struct pt_regs *childregs = task_pt_regs(p);
+	struct switch_stack *swstack = ((struct switch_stack *)childregs) - 1;
 	
 	/* put the pt_regs structure at the end of the new kernel stack page and fix it up
 	 * remember that the task_struct doubles as the kernel stack for the task
 	 */
 
-	childregs = task_pt_regs(p);
-        
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(swstack, 0,
+			sizeof(struct switch_stack) + sizeof(struct pt_regs));
+		swstack->r1 = usp;
+		swstack->r2 = arg;
+		childregs->dccr = 1 << I_DCCR_BITNR;
+		swstack->return_ip = (unsigned long) ret_from_kernel_thread;
+		p->thread.ksp = (unsigned long) swstack;
+		p->thread.usp = 0;
+		return 0;
+	}
 	*childregs = *regs;  /* struct copy of pt_regs */
-        
-        p->set_child_tid = p->clear_child_tid = NULL;
 
         childregs->r10 = 0;  /* child returns 0 after a fork/clone */
-	
-	/* put the switch stack right below the pt_regs */
 
-	swstack = ((struct switch_stack *)childregs) - 1;
+	/* put the switch stack right below the pt_regs */
 
 	swstack->r9 = 0; /* parameter to ret_from_sys_call, 0 == dont restart the syscall */
 
···
 	
 	/* fix the user-mode stackpointer */
 
-	p->thread.usp = usp;	
+	p->thread.usp = usp;
 
 	/* and the kernel-mode one */
 
···
 	return 0;
 }
 
-/* 
- * Be aware of the "magic" 7th argument in the four system-calls below.
- * They need the latest stackframe, which is put as the 7th argument by
- * entry.S. The previous arguments are dummies or actually used, but need
- * to be defined to reach the 7th argument.
- *
- * N.B.: Another method to get the stackframe is to use current_regs(). But
- * it returns the latest stack-frame stacked when going from _user mode_ and
- * some of these (at least sys_clone) are called from kernel-mode sometimes
- * (for example during kernel_thread, above) and thus cannot use it. Thus,
- * to be sure not to get any surprises, we use the method for the other calls
- * as well.
- */
-
-asmlinkage int sys_fork(long r10, long r11, long r12, long r13, long mof, long srp,
-			struct pt_regs *regs)
+asmlinkage int sys_fork(void)
 {
-	return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
+	return do_fork(SIGCHLD, rdusp(), current_pt_regs(), 0, NULL, NULL);
 }
 
 /* if newusp is 0, we just grab the old usp */
 /* FIXME: Is parent_tid/child_tid really third/fourth argument? Update lib? */
 asmlinkage int sys_clone(unsigned long newusp, unsigned long flags,
-			 int* parent_tid, int* child_tid, long mof, long srp,
-			 struct pt_regs *regs)
+			 int* parent_tid, int* child_tid)
 {
 	if (!newusp)
 		newusp = rdusp();
-	return do_fork(flags, newusp, regs, 0, parent_tid, child_tid);
+	return do_fork(flags, newusp, current_pt_regs(), 0, parent_tid, child_tid);
 }
 
 /* vfork is a system call in i386 because of register-pressure - maybe
  * we can remove it and handle it in libc but we put it here until then.
  */
 
-asmlinkage int sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp,
-			 struct pt_regs *regs)
+asmlinkage int sys_vfork(void)
 {
-        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
-}
-
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage int sys_execve(const char *fname,
-			  const char *const *argv,
-			  const char *const *envp,
-			  long r13, long mof, long srp, 
-			  struct pt_regs *regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname(fname);
-	error = PTR_ERR(filename);
-
-	if (IS_ERR(filename))
-	        goto out;
-	error = do_execve(filename->name, argv, envp, regs);
-	putname(filename);
- out:
-	return error;
+        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), current_pt_regs(), 0, NULL, NULL);
 }
 
 unsigned long get_wchan(struct task_struct *p)

arch/cris/arch-v32/kernel/entry.S

···
 	.globl system_call
 	.globl ret_from_intr
 	.globl ret_from_fork
+	.globl ret_from_kernel_thread
 	.globl resume
 	.globl multiple_interrupt
 	.globl nmi_interrupt
···
 	ba  ret_from_sys_call
 	nop
 	.size	ret_from_fork, . - ret_from_fork
+
+	.type	ret_from_kernel_thread,@function
+ret_from_kernel_thread:
+	jsr schedule_tail
+	nop
+	move.d	$r2, $r10
+	jsr	$r1
+	nop
+	moveq	0, $r9			; no syscall restarts, TYVM...
+	ba  ret_from_sys_call
+	nop
+	.size	ret_from_kernel_thread, . - ret_from_kernel_thread
 
 	.type	ret_from_intr,@function
 ret_from_intr:
···
 _ugdb_handle_exception:
 	ba	do_sigtrap		; SIGTRAP the offending process.
 	move.d	[$sp+], $r0		; Restore R0 in delay slot.
-
-	.global kernel_execve
-	.type	kernel_execve,@function
-kernel_execve:
-	move.d __NR_execve, $r9
-	break 13
-	ret
-	nop
-	.size	kernel_execve, . - kernel_execve
 
 	.data
 

arch/cris/arch-v32/kernel/process.c

···
 #include <hwregs/reg_map.h>
 #include <hwregs/timer_defs.h>
 #include <hwregs/intr_vect_defs.h>
+#include <asm/ptrace.h>
 
 extern void stop_watchdog(void);
 
···
 	return task_pt_regs(t)->erp;
 }
 
-static void
-kernel_thread_helper(void* dummy, int (*fn)(void *), void * arg)
-{
-	fn(arg);
-	do_exit(-1); /* Should never be called, return bad exit value. */
-}
-
-/* Create a kernel thread. */
-int
-kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-
-        /* Don't use r10 since that is set to 0 in copy_thread. */
-	regs.r11 = (unsigned long) fn;
-	regs.r12 = (unsigned long) arg;
-	regs.erp = (unsigned long) kernel_thread_helper;
-	regs.ccs = 1 << (I_CCS_BITNR + CCS_SHIFT);
-
-	/* Create the new process. */
-        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
-}
-
 /*
  * Setup the child's kernel stack with a pt_regs and call switch_stack() on it.
  * It will be unnested during _resume and _ret_from_sys_call when the new thread
···
  */
 
 extern asmlinkage void ret_from_fork(void);
+extern asmlinkage void ret_from_kernel_thread(void);
 
 int
 copy_thread(unsigned long clone_flags, unsigned long usp,
-	unsigned long unused,
+	unsigned long arg,
 	struct task_struct *p, struct pt_regs *regs)
 {
-	struct pt_regs *childregs;
-	struct switch_stack *swstack;
+	struct pt_regs *childregs = task_pt_regs(p);
+	struct switch_stack *swstack = ((struct switch_stack *) childregs) - 1;
 
 	/*
 	 * Put the pt_regs structure at the end of the new kernel stack page and
 	 * fix it up. Note: the task_struct doubles as the kernel stack for the
 	 * task.
 	 */
-	childregs = task_pt_regs(p);
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(swstack, 0,
+			sizeof(struct switch_stack) + sizeof(struct pt_regs));
+		swstack->r1 = usp;
+		swstack->r2 = arg;
+		childregs->ccs = 1 << (I_CCS_BITNR + CCS_SHIFT);
+		swstack->return_ip = (unsigned long) ret_from_kernel_thread;
+		p->thread.ksp = (unsigned long) swstack;
+		p->thread.usp = 0;
+		return 0;
+	}
 	*childregs = *regs;	/* Struct copy of pt_regs. */
-        p->set_child_tid = p->clear_child_tid = NULL;
         childregs->r10 = 0;	/* Child returns 0 after a fork/clone. */
 
 	/* Set a new TLS ?
···
 	}
 
 	/* Put the switch stack right below the pt_regs. */
-	swstack = ((struct switch_stack *) childregs) - 1;
 
 	/* Parameter to ret_from_sys_call. 0 is don't restart the syscall. */
 	swstack->r9 = 0;
···
 	return 0;
 }
 
-/*
- * Be aware of the "magic" 7th argument in the four system-calls below.
- * They need the latest stackframe, which is put as the 7th argument by
- * entry.S. The previous arguments are dummies or actually used, but need
- * to be defined to reach the 7th argument.
- *
- * N.B.: Another method to get the stackframe is to use current_regs(). But
- * it returns the latest stack-frame stacked when going from _user mode_ and
- * some of these (at least sys_clone) are called from kernel-mode sometimes
- * (for example during kernel_thread, above) and thus cannot use it. Thus,
- * to be sure not to get any surprises, we use the method for the other calls
- * as well.
- */
 asmlinkage int
-sys_fork(long r10, long r11, long r12, long r13, long mof, long srp,
-	struct pt_regs *regs)
+sys_fork(void)
 {
-	return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
+	return do_fork(SIGCHLD, rdusp(), current_pt_regs(), 0, NULL, NULL);
 }
 
 /* FIXME: Is parent_tid/child_tid really third/fourth argument? Update lib? */
 asmlinkage int
 sys_clone(unsigned long newusp, unsigned long flags, int *parent_tid, int *child_tid,
-	unsigned long tls, long srp, struct pt_regs *regs)
+	unsigned long tls)
 {
 	if (!newusp)
 		newusp = rdusp();
 
-	return do_fork(flags, newusp, regs, 0, parent_tid, child_tid);
+	return do_fork(flags, newusp, current_pt_regs(), 0, parent_tid, child_tid);
 }
 
 /*
···
  * we can remove it and handle it in libc but we put it here until then.
  */
 asmlinkage int
-sys_vfork(long r10, long r11, long r12, long r13, long mof, long srp,
-	struct pt_regs *regs)
+sys_vfork(void)
 {
-	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL, NULL);
-}
-
-/* sys_execve() executes a new program. */
-asmlinkage int
-sys_execve(const char *fname,
-	   const char *const *argv,
-	   const char *const *envp, long r13, long mof, long srp,
-	   struct pt_regs *regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname(fname);
-	error = PTR_ERR(filename);
-
-	if (IS_ERR(filename))
-	        goto out;
-
-	error = do_execve(filename->name, argv, envp, regs);
-	putname(filename);
- out:
-	return error;
+	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), current_pt_regs(), 0, NULL, NULL);
 }
 
 unsigned long

arch/cris/include/asm/processor.h

···
 #define task_pt_regs(task) user_regs(task_thread_info(task))
 #define current_regs() task_pt_regs(current)
 
-extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
-
 unsigned long get_wchan(struct task_struct *p);
 
 #define KSTK_ESP(tsk)   ((tsk) == current ? rdusp() : (tsk)->thread.usp)

arch/cris/include/asm/unistd.h

···
 #define __ARCH_WANT_SYS_SIGPROCMASK
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_SYS_EXECVE
 
 /*
  * "Conditional" syscalls

arch/cris/kernel/crisksyms.c

···
 extern void iounmap(volatile void * __iomem);
 
 /* Platform dependent support */
-EXPORT_SYMBOL(kernel_thread);
 EXPORT_SYMBOL(get_cmos_time);
 EXPORT_SYMBOL(loops_per_usec);
 

arch/h8300/Kconfig

···
 	select GENERIC_IRQ_SHOW
 	select GENERIC_CPU_DEVICES
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 
 config SYMBOL_PREFIX
 	string

arch/h8300/include/asm/processor.h

···
 {
 }
 
-extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
-
 /*
  * Free current thread data structures etc..
  */

arch/h8300/include/asm/ptrace.h

···
 #define user_mode(regs) (!((regs)->ccr & PS_S))
 #define instruction_pointer(regs) ((regs)->pc)
 #define profile_pc(regs) instruction_pointer(regs)
+#define current_pt_regs() ((struct pt_regs *) \
+	(THREAD_SIZE + (unsigned long)current_thread_info()) - 1)
 #endif /* __KERNEL__ */
 #endif /* __ASSEMBLY__ */
 #endif /* _H8300_PTRACE_H */

arch/h8300/include/asm/unistd.h

···
 #define __ARCH_WANT_SYS_SIGPROCMASK
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_SYS_EXECVE
 
 /*
  * "Conditional" syscalls

arch/h8300/kernel/entry.S

···
 .globl SYMBOL_NAME(system_call)
 .globl SYMBOL_NAME(ret_from_exception)
 .globl SYMBOL_NAME(ret_from_fork)
+.globl SYMBOL_NAME(ret_from_kernel_thread)
 .globl SYMBOL_NAME(ret_from_interrupt)
 .globl SYMBOL_NAME(interrupt_redirect_table)
 .globl SYMBOL_NAME(sw_ksp),SYMBOL_NAME(sw_usp)
···
 SYMBOL_NAME_LABEL(ret_from_fork)
 	mov.l	er2,er0
 	jsr	@SYMBOL_NAME(schedule_tail)
+	jmp	@SYMBOL_NAME(ret_from_exception)
+
+SYMBOL_NAME_LABEL(ret_from_kernel_thread)
+	mov.l	er2,er0
+	jsr	@SYMBOL_NAME(schedule_tail)
+	mov.l	@(LER4:16,sp),er0
+	mov.l	@(LER5:16,sp),er1
+	jsr	@er1
 	jmp	@SYMBOL_NAME(ret_from_exception)
 
 SYMBOL_NAME_LABEL(resume)

arch/h8300/kernel/h8300_ksyms.c

···
 
 EXPORT_SYMBOL(ip_fast_csum);
 
-EXPORT_SYMBOL(kernel_thread);
 EXPORT_SYMBOL(enable_irq);
 EXPORT_SYMBOL(disable_irq);
 

arch/h8300/kernel/process.c

···
 EXPORT_SYMBOL(pm_power_off);
 
 asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
 
 /*
  * The idle loop on an H8/300..
···
 		printk("\n");
 }
 
-/*
- * Create a kernel thread
- */
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-	long retval;
-	long clone_arg;
-	mm_segment_t fs;
-
-	fs = get_fs();
-	set_fs (KERNEL_DS);
-	clone_arg = flags | CLONE_VM;
-	__asm__("mov.l sp,er3\n\t"
-		"sub.l er2,er2\n\t"
-		"mov.l %2,er1\n\t"
-		"mov.l %1,er0\n\t"
-		"trapa #0\n\t"
-		"cmp.l sp,er3\n\t"
-		"beq 1f\n\t"
-		"mov.l %4,er0\n\t"
-		"mov.l %3,er1\n\t"
-		"jsr @er1\n\t"
-		"mov.l %5,er0\n\t"
-		"trapa #0\n"
-		"1:\n\t"
-		"mov.l er0,%0"
-		:"=r"(retval)
-		:"i"(__NR_clone),"g"(clone_arg),"g"(fn),"g"(arg),"i"(__NR_exit)
-		:"er0","er1","er2","er3");
-	set_fs (fs);
-	return retval;
-}
-
 void flush_thread(void)
 {
 }
···
 
 	childregs = (struct pt_regs *) (THREAD_SIZE + task_stack_page(p)) - 1;
 
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		childregs->retpc = (unsigned long) ret_from_kernel_thread;
+		childregs->er4 = topstk; /* arg */
+		childregs->er5 = usp; /* fn */
+		p->thread.ksp = (unsigned long)childregs;
+	}
 	*childregs = *regs;
 	childregs->retpc = (unsigned long) ret_from_fork;
 	childregs->er0 = 0;
···
 	p->thread.ksp = (unsigned long)childregs;
 
 	return 0;
-}
-
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage int sys_execve(const char *name,
-			  const char *const *argv,
-			  const char *const *envp,
-			  int dummy, ...)
-{
-	int error;
-	struct filename *filename;
-	struct pt_regs *regs = (struct pt_regs *) ((unsigned char *)&dummy-4);
-
-	filename = getname(name);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		return error;
-	error = do_execve(filename->name, argv, envp, regs);
-	putname(filename);
-	return error;
 }
 
 unsigned long thread_saved_pc(struct task_struct *tsk)

arch/h8300/kernel/sys_h8300.c

···
                ((regs->pc)&0xffffff)-2,regs->orig_er0,regs->er1,regs->er2,regs->er3,regs->er0);
 }
 #endif
-
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-asmlinkage
-int kernel_execve(const char *filename,
-		  const char *const argv[],
-		  const char *const envp[])
-{
-	register long res __asm__("er0");
-	register const char *const *_c __asm__("er3") = envp;
-	register const char *const *_b __asm__("er2") = argv;
-	register const char * _a __asm__("er1") = filename;
-	__asm__ __volatile__ ("mov.l %1,er0\n\t"
-			"trapa	#0\n\t"
-			: "=r" (res)
-			: "g" (__NR_execve),
-			  "g" (_a),
-			  "g" (_b),
-			  "g" (_c)
-			: "cc", "memory");
-	return res;
-}
-
-

arch/hexagon/Kconfig

···
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_CLOCKEVENTS_BROADCAST
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 	---help---
 	  Qualcomm Hexagon is a processor architecture designed for high
 	  performance and low power across a wide variety of applications.

arch/hexagon/include/asm/processor.h

···
 struct task_struct;
 
 /*  this is defined in arch/process.c  */
-extern pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 extern unsigned long thread_saved_pc(struct task_struct *tsk);
 
 extern void start_thread(struct pt_regs *, unsigned long, unsigned long);

arch/hexagon/include/uapi/asm/ptrace.h

···
 extern int regs_query_register_offset(const char *name);
 extern const char *regs_query_register_name(unsigned int offset);
 
+#define current_pt_regs() \
+	((struct pt_regs *) \
+	 ((unsigned long)current_thread_info() + THREAD_SIZE) - 1)
+
 #endif

arch/hexagon/include/uapi/asm/unistd.h

···
  */
 
 #define sys_mmap2 sys_mmap_pgoff
+#define __ARCH_WANT_SYS_EXECVE
 
 #include <asm-generic/unistd.h>

arch/hexagon/kernel/process.c

···
 #include <linux/slab.h>
 
 /*
- * Kernel thread creation.  The desired kernel function is "wrapped"
- * in the kernel_thread_helper function, which does cleanup
- * afterwards.
- */
-static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *))
-{
-	do_exit(fn(arg));
-}
-
-int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-	/*
-	 * Yes, we're exploting illicit knowledge of the ABI here.
-	 */
-	regs.r00 = (unsigned long) arg;
-	regs.r01 = (unsigned long) fn;
-	pt_set_elr(&regs, (unsigned long)kernel_thread_helper);
-	pt_set_kmode(&regs);
-
-	return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/*
  * Program thread launch.  Often defined as a macro in processor.h,
  * but we're shooting for a small footprint and it's not an inner-loop
  * performance-critical operation.
···
  * Copy architecture-specific thread state
  */
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-		unsigned long unused, struct task_struct *p,
+		unsigned long arg, struct task_struct *p,
 		struct pt_regs *regs)
 {
 	struct thread_info *ti = task_thread_info(p);
···
 	childregs = (struct pt_regs *) (((unsigned long) ti + THREAD_SIZE) -
 					sizeof(*childregs));
 
-	memcpy(childregs, regs, sizeof(*childregs));
 	ti->regs = childregs;
 
 	/*
 	 * Establish kernel stack pointer and initial PC for new thread
+	 * Note that unlike the usual situation, we do not copy the
+	 * parent's callee-saved here; those are in pt_regs and whatever
+	 * we leave here will be overridden on return to userland.
 	 */
 	ss = (struct hexagon_switch_stack *) ((unsigned long) childregs -
 						    sizeof(*ss));
 	ss->lr = (unsigned long)ret_from_fork;
 	p->thread.switch_sp = ss;
-
-	/* If User mode thread, set pt_reg stack pointer as per parameter */
-	if (user_mode(childregs)) {
-		pt_set_rte_sp(childregs, usp);
-
-		/* Child sees zero return value */
-		childregs->r00 = 0;
-
-		/*
-		 * The clone syscall has the C signature:
-		 * int [r0] clone(int flags [r0],
-		 *           void *child_frame [r1],
-		 *           void *parent_tid [r2],
-		 *           void *child_tid [r3],
-		 *           void *thread_control_block [r4]);
-		 * ugp is used to provide TLS support.
-		 */
-		if (clone_flags & CLONE_SETTLS)
-			childregs->ugp = childregs->r04;
-
-		/*
-		 * Parent sees new pid -- not necessary, not even possible at
-		 * this point in the fork process
-		 * Might also want to set things like ti->addr_limit
-		 */
-	} else {
-		/*
-		 * If kernel thread, resume stack is kernel stack base.
-		 * Note that this is pointer arithmetic on pt_regs *
-		 */
-		pt_set_rte_sp(childregs, (unsigned long)(childregs + 1));
-		/*
-		 * We need the current thread_info fast path pointer
-		 * set up in pt_regs.  The register to be used is
-		 * parametric for assembler code, but the mechanism
-		 * doesn't drop neatly into C.  Needs to be fixed.
-		 */
-		childregs->THREADINFO_REG = (unsigned long) ti;
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		/* r24 <- fn, r25 <- arg */
+		ss->r2524 = usp | ((u64)arg << 32);
+		pt_set_kmode(childregs);
+		return 0;
 	}
+	memcpy(childregs, regs, sizeof(*childregs));
+	ss->r2524 = 0;
+
+	pt_set_rte_sp(childregs, usp);
+
+	/* Child sees zero return value */
+	childregs->r00 = 0;
 
 	/*
-	 * thread_info pointer is pulled out of task_struct "stack"
-	 * field on switch_to.
+	 * The clone syscall has the C signature:
+	 * int [r0] clone(int flags [r0],
+	 *           void *child_frame [r1],
+	 *           void *parent_tid [r2],
+	 *           void *child_tid [r3],
+	 *           void *thread_control_block [r4]);
+	 * ugp is used to provide TLS support.
 	 */
-	p->stack = (void *)ti;
+	if (clone_flags & CLONE_SETTLS)
+		childregs->ugp = childregs->r04;
+
+	/*
+	 * Parent sees new pid -- not necessary, not even possible at
+	 * this point in the fork process
+	 * Might also want to set things like ti->addr_limit
+	 */
 
 	return 0;
 }

arch/hexagon/kernel/signal.c

···
  */
 asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
 {
-	struct pt_regs *regs = current_thread_info()->regs;
+	struct pt_regs *regs = current_pt_regs();
 
 	return do_sigaltstack(uss, uoss, regs->r29);
 }
 
 asmlinkage int sys_rt_sigreturn(void)
 {
-	struct pt_regs *regs = current_thread_info()->regs;
+	struct pt_regs *regs = current_pt_regs();
 	struct rt_sigframe __user *frame;
 	sigset_t blocked;
 

arch/hexagon/kernel/syscall.c

···
  * See signal.c for signal-related system call wrappers.
  */
 
-asmlinkage int sys_execve(char __user *ufilename,
-			  const char __user *const __user *argv,
-			  const char __user *const __user *envp)
-{
-	struct pt_regs *pregs = current_thread_info()->regs;
-	struct filename *filename;
-	int retval;
-
-	filename = getname(ufilename);
-	retval = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		return retval;
-
-	retval = do_execve(filename->name, argv, envp, pregs);
-	putname(filename);
-
-	return retval;
-}
-
 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 			 unsigned long parent_tidp, unsigned long child_tidp)
 {
-	struct pt_regs *pregs = current_thread_info()->regs;
+	struct pt_regs *pregs = current_pt_regs();
 
 	if (!newsp)
 		newsp = pregs->SP;
 	return do_fork(clone_flags, newsp, pregs, 0, (int __user *)parent_tidp,
 		       (int __user *)child_tidp);
-}
-
-/*
- * Do a system call from the kernel, so as to have a proper pt_regs
- * and recycle the sys_execvpe infrustructure.
- */
-int kernel_execve(const char *filename,
-		  const char *const argv[], const char *const envp[])
-{
-	register unsigned long __a0 asm("r0") = (unsigned long) filename;
-	register unsigned long __a1 asm("r1") = (unsigned long) argv;
-	register unsigned long __a2 asm("r2") = (unsigned long) envp;
-	int retval;
-
-	__asm__ volatile(
-		"	R6 = #%4;\n"
-		"	trap0(#1);\n"
-		"	%0 = R0;\n"
-		: "=r" (retval)
-		: "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
-	);
-
-	return retval;
 }

arch/hexagon/kernel/vm_entry.S

···
 	.globl ret_from_fork
 ret_from_fork:
 	call schedule_tail
+	P0 = cmp.eq(R24, #0);
+	if P0 jump return_from_syscall
+	R0 = R25;
+	callr R24
 	jump return_from_syscall

arch/ia64/Kconfig

···
 	select GENERIC_TIME_VSYSCALL_OLD
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 	default y
 	help
 	  The Itanium Processor Family is Intel's 64-bit successor to

arch/ia64/include/asm/processor.h

···
  */
 #define release_thread(dead_task)
 
-/*
- * This is the mechanism for creating a new kernel thread.
- *
- * NOTE 1: Only a kernel-only process (ie the swapper or direct
- * descendants who haven't done an "execve()") should use this: it
- * will work within a system call from a "real" process, but the
- * process memory space will not be free'd until both the parent and
- * the child have exited.
- *
- * NOTE 2: This MUST NOT be an inlined function.  Otherwise, we get
- * into trouble in init/main.c when the child thread returns to
- * do_basic_setup() and the timing is such that free_initmem() has
- * been called already.
- */
-extern pid_t kernel_thread (int (*fn)(void *), void *arg, unsigned long flags);
-
 /* Get wait channel for task P.  */
 extern unsigned long get_wchan (struct task_struct *p);
 

arch/ia64/include/asm/unistd.h

···
 
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_SYS_EXECVE
 
 #if !defined(__ASSEMBLY__) && !defined(ASSEMBLER)
 

arch/ia64/kernel/entry.S

···
 	 * Allocate 8 input registers since ptrace() may clobber them
 	 */
 	.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
-	alloc loc1=ar.pfs,8,2,4,0
+	alloc loc1=ar.pfs,8,2,3,0
 	mov loc0=rp
 	.body
 	mov out0=in0			// filename
 	;;				// stop bit between alloc and call
 	mov out1=in1			// argv
 	mov out2=in2			// envp
-	add out3=16,sp			// regs
 	br.call.sptk.many rp=sys_execve
 .ret0:
 	cmp4.ge p6,p7=r8,r0
···
 	sxt4 r8=r8			// return 64-bit result
 	;;
 	stf.spill [sp]=f0
-(p6)	cmp.ne pKStk,pUStk=r0,r0	// a successful execve() lands us in user-mode...
 	mov rp=loc0
 (p6)	mov ar.pfs=r0			// clear ar.pfs on success
 (p7)	br.ret.sptk.many rp
···
 	br.ret.sptk.many rp
 END(prefetch_stack)
 
-GLOBAL_ENTRY(kernel_execve)
-	rum psr.ac
-	mov r15=__NR_execve			// put syscall number in place
-	break __BREAK_SYSCALL
-	br.ret.sptk.many rp
-END(kernel_execve)
-
-GLOBAL_ENTRY(clone)
-	mov r15=__NR_clone			// put syscall number in place
-	break __BREAK_SYSCALL
-	br.ret.sptk.many rp
-END(clone)
-
 	/*
 	 * Invoke a system call, but do some tracing before and after the call.
 	 * We MUST preserve the current register frame throughout this routine
···
 .ret4:	br.cond.sptk ia64_leave_kernel
 END(ia64_strace_leave_kernel)
 
+ENTRY(call_payload)
+	.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(0)
+	/* call the kernel_thread payload; fn is in r4, arg - in r5 */
+	alloc loc1=ar.pfs,0,3,1,0
+	mov loc0=rp
+	mov loc2=gp
+	mov out0=r5		// arg
+	ld8 r14 = [r4], 8	// fn.address
+	;;
+	mov b6 = r14
+	ld8 gp = [r4]		// fn.gp
+	;;
+	br.call.sptk.many rp=b6	// fn(arg)
+.ret12:	mov gp=loc2
+	mov rp=loc0
+	mov ar.pfs=loc1
+	/* ... and if it has returned, we are going to userland */
+	cmp.ne pKStk,pUStk=r0,r0
+	br.ret.sptk.many rp
+END(call_payload)
+
 GLOBAL_ENTRY(ia64_ret_from_clone)
 	PT_REGS_UNWIND_INFO(0)
 {	/*
···
 	br.call.sptk.many rp=ia64_invoke_schedule_tail
 }
 .ret8:
+(pKStk)	br.call.sptk.many rp=call_payload
 	adds r2=TI_FLAGS+IA64_TASK_SIZE,r13
 	;;
 	ld4 r2=[r2]

arch/ia64/kernel/head.S

···
 END(cycle_to_cputime)
 #endif /* CONFIG_VIRT_CPU_ACCOUNTING */
 
-GLOBAL_ENTRY(start_kernel_thread)
-	.prologue
-	.save rp, r0				// this is the end of the call-chain
-	.body
-	alloc r2 = ar.pfs, 0, 0, 2, 0
-	mov out0 = r9
-	mov out1 = r11;;
-	br.call.sptk.many rp = kernel_thread_helper;;
-	mov out0 = r8
-	br.call.sptk.many rp = sys_exit;;
-1:	br.sptk.few 1b				// not reached
-END(start_kernel_thread)
-
 #ifdef CONFIG_IA64_BRL_EMU
 
 /*

arch/ia64/kernel/process.c

···
 	struct pt_regs *child_ptregs;
 	int retval = 0;
 
-#ifdef CONFIG_SMP
-	/*
-	 * For SMP idle threads, fork_by_hand() calls do_fork with
-	 * NULL regs.
-	 */
-	if (!regs)
-		return 0;
-#endif
-
-	stack = ((struct switch_stack *) regs) - 1;
-
 	child_ptregs = (struct pt_regs *) ((unsigned long) p + IA64_STK_OFFSET) - 1;
 	child_stack = (struct switch_stack *) child_ptregs - 1;
 
-	/* copy parent's switch_stack & pt_regs to child: */
-	memcpy(child_stack, stack, sizeof(*child_ptregs) + sizeof(*child_stack));
-
 	rbs = (unsigned long) current + IA64_RBS_OFFSET;
 	child_rbs = (unsigned long) p + IA64_RBS_OFFSET;
-	rbs_size = stack->ar_bspstore - rbs;
-
-	/* copy the parent's register backing store to the child: */
-	memcpy((void *) child_rbs, (void *) rbs, rbs_size);
-
-	if (likely(user_mode(child_ptregs))) {
-		if (clone_flags & CLONE_SETTLS)
-			child_ptregs->r13 = regs->r16;	/* see sys_clone2() in entry.S */
-		if (user_stack_base) {
-			child_ptregs->r12 = user_stack_base + user_stack_size - 16;
-			child_ptregs->ar_bspstore = user_stack_base;
-			child_ptregs->ar_rnat = 0;
-			child_ptregs->loadrs = 0;
-		}
-	} else {
-		/*
-		 * Note: we simply preserve the relative position of
-		 * the stack pointer here.  There is no need to
-		 * allocate a scratch area here, since that will have
-		 * been taken care of by the caller of sys_clone()
-		 * already.
-		 */
-		child_ptregs->r12 = (unsigned long) child_ptregs - 16; /* kernel sp */
-		child_ptregs->r13 = (unsigned long) p;		/* set `current' pointer */
-	}
-	child_stack->ar_bspstore = child_rbs + rbs_size;
-	child_stack->b0 = (unsigned long) &ia64_ret_from_clone;
 
 	/* copy parts of thread_struct: */
 	p->thread.ksp = (unsigned long) child_stack - 16;
-
-	/* stop some PSR bits from being inherited.
-	 * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
-	 * therefore we must specify them explicitly here and not include them in
-	 * IA64_PSR_BITS_TO_CLEAR.
-	 */
-	child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
-				 & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));
 
 	/*
 	 * NOTE: The calling convention considers all floating point
···
 #	define THREAD_FLAGS_TO_SET	0
 	p->thread.flags = ((current->thread.flags & ~THREAD_FLAGS_TO_CLEAR)
 			   | THREAD_FLAGS_TO_SET);
+
 	ia64_drop_fpu(p);	/* don't pick up stale state from a CPU's fph */
+
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		if (unlikely(!user_stack_base)) {
+			/* fork_idle() called us */
+			return 0;
+		}
+		memset(child_stack, 0, sizeof(*child_ptregs) + sizeof(*child_stack));
+		child_stack->r4 = user_stack_base;	/* payload */
+		child_stack->r5 = user_stack_size;	/* argument */
+		/*
+		 * Preserve PSR bits, except for bits 32-34 and 37-45,
+		 * which we can't read.
+		 */
+		child_ptregs->cr_ipsr = ia64_getreg(_IA64_REG_PSR) | IA64_PSR_BN;
+		/* mark as valid, empty frame */
+		child_ptregs->cr_ifs = 1UL << 63;
+		child_stack->ar_fpsr = child_ptregs->ar_fpsr
+			= ia64_getreg(_IA64_REG_AR_FPSR);
+		child_stack->pr = (1 << PRED_KERNEL_STACK);
+		child_stack->ar_bspstore = child_rbs;
+		child_stack->b0 = (unsigned long) &ia64_ret_from_clone;
+
+		/* stop some PSR bits from being inherited.
+		 * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
+		 * therefore we must specify them explicitly here and not include them in
+		 * IA64_PSR_BITS_TO_CLEAR.
+		 */
+		child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
+				 & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));
+
+		return 0;
+	}
+	stack = ((struct switch_stack *) regs) - 1;
+	/* copy parent's switch_stack & pt_regs to child: */
+	memcpy(child_stack, stack, sizeof(*child_ptregs) + sizeof(*child_stack));
+
+	/* copy the parent's register backing store to the child: */
+	rbs_size = stack->ar_bspstore - rbs;
+	memcpy((void *) child_rbs, (void *) rbs, rbs_size);
+	if (clone_flags & CLONE_SETTLS)
+		child_ptregs->r13 = regs->r16;	/* see sys_clone2() in entry.S */
+	if (user_stack_base) {
+		child_ptregs->r12 = user_stack_base + user_stack_size - 16;
+		child_ptregs->ar_bspstore = user_stack_base;
+		child_ptregs->ar_rnat = 0;
+		child_ptregs->loadrs = 0;
+	}
+	child_stack->ar_bspstore = child_rbs + rbs_size;
+	child_stack->b0 = (unsigned long) &ia64_ret_from_clone;
+
+	/* stop some PSR bits from being inherited.
+	 * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
+	 * therefore we must specify them explicitly here and not include them in
+	 * IA64_PSR_BITS_TO_CLEAR.
+	 */
+	child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
+				 & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));
 
 #ifdef CONFIG_PERFMON
 	if (current->thread.pfm_context)
···
 {
 	unw_init_running(do_dump_fpu, dst);
 	return 1;	/* f0-f31 are always valid so we always return 1 */
-}
-
-long
-sys_execve (const char __user *filename,
-	    const char __user *const __user *argv,
-	    const char __user *const __user *envp,
-	    struct pt_regs *regs)
-{
-	struct filename *fname;
-	int error;
-
-	fname = getname(filename);
-	error = PTR_ERR(fname);
-	if (IS_ERR(fname))
-		goto out;
-	error = do_execve(fname->name, argv, envp, regs);
-	putname(fname);
-out:
-	return error;
-}
-
-pid_t
-kernel_thread (int (*fn)(void *), void *arg, unsigned long flags)
-{
-	extern void start_kernel_thread (void);
-	unsigned long *helper_fptr = (unsigned long *) &start_kernel_thread;
-	struct {
-		struct switch_stack sw;
-		struct pt_regs pt;
-	} regs;
-
-	memset(&regs, 0, sizeof(regs));
-	regs.pt.cr_iip = helper_fptr[0];	/* set entry point (IP) */
-	regs.pt.r1 = helper_fptr[1];		/* set GP */
-	regs.pt.r9 = (unsigned long) fn;	/* 1st argument */
-	regs.pt.r11 = (unsigned long) arg;	/* 2nd argument */
-	/* Preserve PSR bits, except for bits 32-34 and 37-45, which we can't read.  */
-	regs.pt.cr_ipsr = ia64_getreg(_IA64_REG_PSR) | IA64_PSR_BN;
-	regs.pt.cr_ifs = 1UL << 63;		/* mark as valid, empty frame */
-	regs.sw.ar_fpsr = regs.pt.ar_fpsr = ia64_getreg(_IA64_REG_AR_FPSR);
-	regs.sw.ar_bspstore = (unsigned long) current + IA64_RBS_OFFSET;
-	regs.sw.pr = (1 << PRED_KERNEL_STACK);
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs.pt, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/* This gets called from kernel_thread() via ia64_invoke_thread_helper().  */
-int
-kernel_thread_helper (int (*fn)(void *), void *arg)
-{
-	return (*fn)(arg);
 }
 
 /*

arch/m32r/Kconfig

···
 	select GENERIC_ATOMIC64
 	select ARCH_USES_GETTIMEOFFSET
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 
 config SBUS
 	bool

arch/m32r/include/asm/processor.h

···
 /* Free all resources held by a thread. */
 extern void release_thread(struct task_struct *);
 
-/*
- * create a kernel thread without removing it from tasklists
- */
-extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
-
 /* Copy and release all segment info associated with a VM */
 extern void copy_segments(struct task_struct *p, struct mm_struct * mm);
 extern void release_segments(struct mm_struct * mm);

arch/m32r/include/asm/ptrace.h

···
 
 #define task_pt_regs(task) \
         ((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1)
+#define current_pt_regs() ((struct pt_regs *) \
+	((unsigned long)current_thread_info() + THREAD_SIZE) - 1)
 
 #endif /* __KERNEL */
 

arch/m32r/include/asm/unistd.h

···
 #define __ARCH_WANT_SYS_OLDUMOUNT
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_SYS_EXECVE
 
 #define __IGNORE_lchown
 #define __IGNORE_setuid

arch/m32r/kernel/entry.S

···
 	and	\reg, sp
 	.endm
 
+ENTRY(ret_from_kernel_thread)
+	pop	r0
+	bl	schedule_tail
+	GET_THREAD_INFO(r8)
+	ld	r0, R0(r8)
+	ld	r1, R1(r8)
+	jl	r1
+	bra	syscall_exit
+
 ENTRY(ret_from_fork)
 	pop	r0
 	bl	schedule_tail

arch/m32r/kernel/process.c

···
 }
 
 /*
- * Create a kernel thread
- */
-
-/*
- * This is the mechanism for creating a new kernel thread.
- *
- * NOTE! Only a kernel-only process(ie the swapper or direct descendants
- * who haven't done an "execve()") should use this: it will work within
- * a system call from a "real" process, but the process memory space will
- * not be free'd until both the parent and the child have exited.
- */
-static void kernel_thread_helper(void *nouse, int (*fn)(void *), void *arg)
-{
-	fn(arg);
-	do_exit(-1);
-}
-
-int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof (regs));
-	regs.r1 = (unsigned long)fn;
-	regs.r2 = (unsigned long)arg;
-
-	regs.bpc = (unsigned long)kernel_thread_helper;
-
-	regs.psw = M32R_PSW_BIE;
-
-	/* Ok, create the new process. */
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
-		NULL);
-}
-
-/*
  * Free current thread data structures etc..
  */
 void exit_thread(void)
···
 }
 
 int copy_thread(unsigned long clone_flags, unsigned long spu,
-	unsigned long unused, struct task_struct *tsk, struct pt_regs *regs)
+	unsigned long arg, struct task_struct *tsk, struct pt_regs *regs)
 {
 	struct pt_regs *childregs = task_pt_regs(tsk);
 	extern void ret_from_fork(void);
+	extern void ret_from_kernel_thread(void);
 
-	/* Copy registers */
-	*childregs = *regs;
-
-	childregs->spu = spu;
-	childregs->r0 = 0;	/* Child gets zero as return value */
-	regs->r0 = tsk->pid;
+	if (unlikely(tsk->flags & PF_KTHREAD)) {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		childregs->psw = M32R_PSW_BIE;
+		childregs->r1 = spu;	/* fn */
+		childregs->r0 = arg;
+		tsk->thread.lr = (unsigned long)ret_from_kernel_thread;
+	} else {
+		/* Copy registers */
+		*childregs = *regs;
+		childregs->spu = spu;
+		childregs->r0 = 0;	/* Child gets zero as return value */
+		tsk->thread.lr = (unsigned long)ret_from_fork;
+	}
 	tsk->thread.sp = (unsigned long)childregs;
-	tsk->thread.lr = (unsigned long)ret_from_fork;
 
 	return 0;
 }
 
-asmlinkage int sys_fork(unsigned long r0, unsigned long r1, unsigned long r2,
-	unsigned long r3, unsigned long r4, unsigned long r5, unsigned long r6,
-	struct pt_regs regs)
+asmlinkage int sys_fork(void)
 {
 #ifdef CONFIG_MMU
-	return do_fork(SIGCHLD, regs.spu, &regs, 0, NULL, NULL);
+	struct pt_regs *regs = current_pt_regs();
+	return do_fork(SIGCHLD, regs->spu, regs, 0, NULL, NULL);
 #else
 	return -EINVAL;
 #endif /* CONFIG_MMU */
···
 
 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 			 unsigned long parent_tidptr,
-			 unsigned long child_tidptr,
-			 unsigned long r4, unsigned long r5, unsigned long r6,
-			 struct pt_regs regs)
+			 unsigned long child_tidptr)
 {
+	struct pt_regs *regs = current_pt_regs();
 	if (!newsp)
-		newsp = regs.spu;
+		newsp = regs->spu;
 
-	return do_fork(clone_flags, newsp, &regs, 0,
+	return do_fork(clone_flags, newsp, regs, 0,
 		       (int __user *)parent_tidptr, (int __user *)child_tidptr);
 }
 
···
  * do not have enough call-clobbered registers to hold all
  * the information you need.
  */
-asmlinkage int sys_vfork(unsigned long r0, unsigned long r1, unsigned long r2,
-	unsigned long r3, unsigned long r4, unsigned long r5, unsigned long r6,
-	struct pt_regs regs)
+asmlinkage int sys_vfork(void)
 {
-	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.spu, &regs, 0,
+	struct pt_regs *regs = current_pt_regs();
+	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->spu, regs, 0,
 			NULL, NULL);
-}
-
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage int sys_execve(const char __user *ufilename,
-			  const char __user *const __user *uargv,
-			  const char __user *const __user *uenvp,
-			  unsigned long r3, unsigned long r4, unsigned long r5,
-			  unsigned long r6, struct pt_regs regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname(ufilename);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-
-	error = do_execve(filename->name, uargv, uenvp, &regs);
-	putname(filename);
-out:
-	return error;
 }
 
 /*

arch/m32r/kernel/sys_m32r.c

···
 	/* Not implemented yet. */
 	return -ENOSYS;
 }
-
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-int kernel_execve(const char *filename,
-		  const char *const argv[],
-		  const char *const envp[])
-{
-	register long __scno __asm__ ("r7") = __NR_execve;
-	register long __arg3 __asm__ ("r2") = (long)(envp);
-	register long __arg2 __asm__ ("r1") = (long)(argv);
-	register long __res __asm__ ("r0") = (long)(filename);
-	__asm__ __volatile__ (
-		"trap #" SYSCALL_VECTOR "|| nop"
-		: "=r" (__res)
-		: "r" (__scno), "0" (__res), "r" (__arg2),
-			"r" (__arg3)
-		: "memory");
-	return __res;
-}

arch/m68k/Kconfig

···
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select ARCH_USES_GETTIMEOFFSET if MMU && !COLDFIRE
 	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_REL
 	select MODULES_USE_ELF_RELA

arch/m68k/include/asm/unistd.h

···
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
 #define __ARCH_WANT_SYS_EXECVE
-#define __ARCH_WANT_KERNEL_EXECVE
 
 /*
  * "Conditional" syscalls

arch/m68k/kernel/entry.S

···
 	| a3 contains the kernel thread payload, d7 - its argument
 	movel	%d1,%sp@-
 	jsr	schedule_tail
-	GET_CURRENT(%d0)
 	movel	%d7,(%sp)
 	jsr	%a3@
 	addql	#4,%sp
-	movel	%d0,(%sp)
-	jra	sys_exit
-
-ENTRY(ret_from_kernel_execve)
-	movel	4(%sp), %sp
-	GET_CURRENT(%d0)
 	jra	ret_from_exception
 
 #if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)

arch/microblaze/Kconfig

···
 	select GENERIC_ATOMIC64
 	select GENERIC_CLOCKEVENTS
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 
 config SWAP
 	def_bool n

arch/microblaze/include/asm/processor.h

···
 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp);
 
 extern void ret_from_fork(void);
+extern void ret_from_kernel_thread(void);
 
 # endif /* __ASSEMBLY__ */
 
···
 extern unsigned long thread_saved_pc(struct task_struct *t);
 
 extern unsigned long get_wchan(struct task_struct *p);
-
-/*
- * create a kernel thread without removing it from tasklists
- */
-extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 
 # define KSTK_EIP(tsk)	(0)
 # define KSTK_ESP(tsk)	(0)
···
 extern inline void release_thread(struct task_struct *dead_task)
 {
 }
-
-extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 
 /* Free current thread data structures etc.  */
 static inline void exit_thread(void)

arch/microblaze/include/asm/unistd.h

···
 #define __ARCH_WANT_SYS_SIGPROCMASK
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_SYS_EXECVE
 
 /*
  * "Conditional" syscalls

arch/microblaze/kernel/entry-nommu.S

···
 	brid	ret_to_user
 	nop
 
+ENTRY(ret_from_kernel_thread)
+	brlid	r15, schedule_tail
+	addk	r5, r0, r3
+	brald	r15, r20
+	addk	r5, r0, r19
+	brid	ret_to_user
+	addk	r3, r0, r0
+
 work_pending:
 	enable_irq
 
···
 sys_clone:
 	brid	microblaze_clone
 	addk	r7, r1, r0
-
-sys_execve:
-	brid	microblaze_execve
-	addk	r8, r1, r0
 
 sys_rt_sigreturn_wrapper:
 	brid	sys_rt_sigreturn

arch/microblaze/kernel/entry.S

···
 	swi	r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
 	addi	r14, r14, 4	/* return address is 4 byte after call */
 
-	mfs	r1, rmsr
-	nop
-	andi	r1, r1, MSR_UMS
-	bnei	r1, 1f
-
-/* Kernel-mode state save - kernel execve */
-	lwi	r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
-	tophys(r1,r1);
-
-	addik	r1, r1, -PT_SIZE; /* Make room on the stack. */
-	SAVE_REGS
-
-	swi	r1, r1, PT_MODE; /* pt_regs -> kernel mode */
-	brid	2f;
-	nop;				/* Fill delay slot */
-
-/* User-mode state save.  */
-1:
 	lwi	r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
 	tophys(r1,r1);
 	lwi	r1, r1, TS_THREAD_INFO;	/* get stack from task_struct */
···
    saved context).  */
 C_ENTRY(ret_from_fork):
 	bralid	r15, schedule_tail; /* ...which is schedule_tail's arg */
-	add	r3, r5, r0;	/* switch_thread returns the prev task */
+	add	r5, r3, r0;	/* switch_thread returns the prev task */
 				/* ( in the delay slot ) */
 	brid	ret_from_trap;	/* Do normal trap return */
 	add	r3, r0, r0;	/* Child's fork call should return 0. */
+
+C_ENTRY(ret_from_kernel_thread):
+	bralid	r15, schedule_tail; /* ...which is schedule_tail's arg */
+	add	r5, r3, r0;	/* switch_thread returns the prev task */
+				/* ( in the delay slot ) */
+	brald	r15, r20	/* fn was left in r20 */
+	addk	r5, r0, r19	/* ... and argument - in r19 */
+	brid	ret_from_trap
+	add	r3, r0, r0
 
 C_ENTRY(sys_vfork):
 	brid	microblaze_vfork	/* Do real work (tail-call) */
···
 	/* do_fork will pick up TLS from regs->r10.  */
 	brid	do_fork		/* Do real work (tail-call) */
 	add     r8, r0, r0;             /* Arg 3: (unused) */
-
-C_ENTRY(sys_execve):
-	brid	microblaze_execve;	/* Do real work (tail-call).*/
-	addik	r8, r1, 0;		/* add user context as 4th arg */
 
 C_ENTRY(sys_rt_sigreturn_wrapper):
 	brid	sys_rt_sigreturn	/* Do real work */

arch/microblaze/kernel/process.c

···
 }
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-		unsigned long unused,
+		unsigned long arg,
 		struct task_struct *p, struct pt_regs *regs)
 {
 	struct pt_regs *childregs = task_pt_regs(p);
 	struct thread_info *ti = task_thread_info(p);
 
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		/* if we're creating a new kernel thread then just zeroing all
+		 * the registers. That's OK for a brand new thread.*/
+		memset(childregs, 0, sizeof(struct pt_regs));
+		memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
+		ti->cpu_context.r1  = (unsigned long)childregs;
+		ti->cpu_context.r20 = (unsigned long)usp; /* fn */
+		ti->cpu_context.r19 = (unsigned long)arg;
+		childregs->pt_mode = 1;
+		local_save_flags(childregs->msr);
+#ifdef CONFIG_MMU
+		ti->cpu_context.msr = childregs->msr & ~MSR_IE;
+#endif
+		ti->cpu_context.r15 = (unsigned long)ret_from_kernel_thread - 8;
+		return 0;
+	}
 	*childregs = *regs;
-	if (user_mode(regs))
-		childregs->r1 = usp;
-	else
-		childregs->r1 = ((unsigned long) ti) + THREAD_SIZE;
+	childregs->r1 = usp;
 
-#ifndef CONFIG_MMU
 	memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
 	ti->cpu_context.r1 = (unsigned long)childregs;
+#ifndef CONFIG_MMU
 	ti->cpu_context.msr = (unsigned long)childregs->msr;
 #else
+	childregs->msr |= MSR_UMS;
 
-	/* if creating a kernel thread then update the current reg (we don't
-	 * want to use the parent's value when restoring by POP_STATE) */
-	if (kernel_mode(regs))
-		/* save new current on stack to use POP_STATE */
-		childregs->CURRENT_TASK = (unsigned long)p;
-	/* if returning to user then use the parent's value of this register */
-
-	/* if we're creating a new kernel thread then just zeroing all
-	 * the registers. That's OK for a brand new thread.*/
-	/* Pls. note that some of them will be restored in POP_STATE */
-	if (kernel_mode(regs))
-		memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
-	/* if this thread is created for fork/vfork/clone, then we want to
-	 * restore all the parent's context */
-	/* in addition to the registers which will be restored by POP_STATE */
-	else {
-		ti->cpu_context = *(struct cpu_context *)regs;
-		childregs->msr |= MSR_UMS;
-	}
-
-	/* FIXME STATE_SAVE_PT_OFFSET; */
-	ti->cpu_context.r1  = (unsigned long)childregs;
 	/* we should consider the fact that childregs is a copy of the parent
 	 * regs which were saved immediately after entering the kernel state
 	 * before enabling VM. This MSR will be restored in switch_to and
···
 }
 #endif
 
-static void kernel_thread_helper(int (*fn)(void *), void *arg)
-{
-	fn(arg);
-	do_exit(-1);
-}
-
-int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-	/* store them in non-volatile registers */
-	regs.r5 = (unsigned long)fn;
-	regs.r6 = (unsigned long)arg;
-	local_save_flags(regs.msr);
-	regs.pc = (unsigned long)kernel_thread_helper;
-	regs.pt_mode = 1;
-
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
-			&regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL_GPL(kernel_thread);
-
 unsigned long get_wchan(struct task_struct *p)
 {
 /* TBD (used by procfs) */
···
 	regs->pt_mode = 0;
 #ifdef CONFIG_MMU
 	regs->msr |= MSR_UMS;
+	regs->msr &= ~MSR_VM;
 #endif
 }
 

arch/microblaze/kernel/sys_microblaze.c

···
 	return do_fork(flags, stack, regs, 0, NULL, NULL);
 }
 
-asmlinkage long microblaze_execve(const char __user *filenamei,
-				  const char __user *const __user *argv,
-				  const char __user *const __user *envp,
-				  struct pt_regs *regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname(filenamei);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-	error = do_execve(filename->name, argv, envp, regs);
-	putname(filename);
-out:
-	return error;
-}
-
 asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
 			unsigned long prot, unsigned long flags,
 			unsigned long fd, off_t pgoff)
···
 		return -EINVAL;
 
 	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> PAGE_SHIFT);
-}
-
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-int kernel_execve(const char *filename,
-		  const char *const argv[],
-		  const char *const envp[])
-{
-	register const char *__a __asm__("r5") = filename;
-	register const void *__b __asm__("r6") = argv;
-	register const void *__c __asm__("r7") = envp;
-	register unsigned long __syscall __asm__("r12") = __NR_execve;
-	register unsigned long __ret __asm__("r3");
-	__asm__ __volatile__ ("brki r14, 0x8"
-			: "=r" (__ret), "=r" (__syscall)
-			: "1" (__syscall), "r" (__a), "r" (__b), "r" (__c)
-			: "r4", "r8", "r9",
-			"r10", "r11", "r14", "cc", "memory");
-	return __ret;
 }

arch/mips/Kconfig

···
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_REL
 	select MODULES_USE_ELF_RELA if 64BIT
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 
 menu "Machine selection"
 

arch/mips/include/asm/processor.h

···
 /* Free all resources held by a thread. */
 #define release_thread(thread) do { } while(0)
 
-extern long kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
-
 extern unsigned long thread_saved_pc(struct task_struct *tsk);
 
 /*

arch/mips/include/asm/ptrace.h

···
 		die(str, regs);
 }
 
+#define current_pt_regs()						\
+({									\
+	unsigned long sp = (unsigned long)__builtin_frame_address(0);	\
+	(struct pt_regs *)((sp | (THREAD_SIZE - 1)) + 1 - 32) - 1;	\
+})
+
 #endif /* _ASM_PTRACE_H */

arch/mips/include/asm/unistd.h

···
 #define __ARCH_OMIT_COMPAT_SYS_GETDENTS64
 #define __ARCH_WANT_OLD_READDIR
 #define __ARCH_WANT_SYS_ALARM
+#define __ARCH_WANT_SYS_EXECVE
 #define __ARCH_WANT_SYS_GETHOSTNAME
 #define __ARCH_WANT_SYS_IPC
 #define __ARCH_WANT_SYS_PAUSE

arch/mips/kernel/entry.S

···
 	b	need_resched
 #endif
 
+FEXPORT(ret_from_kernel_thread)
+	jal	schedule_tail		# a0 = struct task_struct *prev
+	move	a0, s1
+	jal	s0
+	j	syscall_exit
+
 FEXPORT(ret_from_fork)
 	jal	schedule_tail		# a0 = struct task_struct *prev
 

arch/mips/kernel/linux32.c

···
  *
  * Copyright (C) 2000 Silicon Graphics, Inc.
  * Written by Ulf Carlsson ([e-mail])
- * sys32_execve from ia64/ia32 code, Feb 2000, Kanoj Sarcar ([e-mail])
  */
 #include <linux/compiler.h>
 #include <linux/mm.h>
···
 		goto out;
 	error = sys_mmap_pgoff(addr, len, prot, flags, fd,
 			       pgoff >> (PAGE_SHIFT-12));
-out:
-	return error;
-}
-
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage int sys32_execve(nabi_no_regargs struct pt_regs regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname(compat_ptr(regs.regs[4]));
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-	error = compat_do_execve(filename->name, compat_ptr(regs.regs[5]),
-				 compat_ptr(regs.regs[6]), &regs);
-	putname(filename);
-
 out:
 	return error;
 }

arch/mips/kernel/mips_ksyms.c

···
 EXPORT_SYMBOL(memcpy);
 EXPORT_SYMBOL(memmove);
 
-EXPORT_SYMBOL(kernel_thread);
-
 /*
  * Functions that operate on entire pages.  Mostly used by memory management.
  */

arch/mips/kernel/process.c

···
 }
 
 asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
 
 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
 {
···
 }
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-	unsigned long unused, struct task_struct *p, struct pt_regs *regs)
+	unsigned long arg, struct task_struct *p, struct pt_regs *regs)
 {
 	struct thread_info *ti = task_thread_info(p);
 	struct pt_regs *childregs;
···
 	childregs = (struct pt_regs *) childksp - 1;
 	/*  Put the stack after the struct pt_regs.  */
 	childksp = (unsigned long) childregs;
+	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		unsigned long status = p->thread.cp0_status;
+		memset(childregs, 0, sizeof(struct pt_regs));
+		ti->addr_limit = KERNEL_DS;
+		p->thread.reg16 = usp; /* fn */
+		p->thread.reg17 = arg;
+		p->thread.reg29 = childksp;
+		p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
+#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
+		status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
+			 ((status & (ST0_KUC | ST0_IEC)) << 2);
+#else
+		status |= ST0_EXL;
+#endif
+		childregs->cp0_status = status;
+		return 0;
+	}
 	*childregs = *regs;
 	childregs->regs[7] = 0;	/* Clear error flag */
-
 	childregs->regs[2] = 0;	/* Child gets zero as return value */
+	childregs->regs[29] = usp;
+	ti->addr_limit = USER_DS;
 
-	if (childregs->cp0_status & ST0_CU0) {
-		childregs->regs[28] = (unsigned long) ti;
-		childregs->regs[29] = childksp;
-		ti->addr_limit = KERNEL_DS;
-	} else {
-		childregs->regs[29] = usp;
-		ti->addr_limit = USER_DS;
-	}
 	p->thread.reg29 = (unsigned long) childregs;
 	p->thread.reg31 = (unsigned long) ret_from_fork;
 
···
 	 * New tasks lose permission to use the fpu. This accelerates context
 	 * switching for most programs since they don't use the fpu.
 	 */
-	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
 	childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
 
 #ifdef CONFIG_MIPS_MT_SMTC
···
 	memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
 
 	return 1;
-}
-
-/*
- * Create a kernel thread
- */
-static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *))
-{
-	do_exit(fn(arg));
-}
-
-long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-
-	regs.regs[4] = (unsigned long) arg;
-	regs.regs[5] = (unsigned long) fn;
-	regs.cp0_epc = (unsigned long) kernel_thread_helper;
-	regs.cp0_status = read_c0_status();
-#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
-	regs.cp0_status = (regs.cp0_status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
-			  ((regs.cp0_status & (ST0_KUC | ST0_IEC)) << 2);
-#else
-	regs.cp0_status |= ST0_EXL;
-#endif
-
-	/* Ok, create the new process.. */
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 }
 
 /*

arch/mips/kernel/scall64-n32.S

···
 	PTR	sys_getsockopt
 	PTR	sys_clone			/* 6055 */
 	PTR	sys_fork
-	PTR	sys32_execve
+	PTR	compat_sys_execve
 	PTR	sys_exit
 	PTR	compat_sys_wait4
 	PTR	sys_kill			/* 6060 */

arch/mips/kernel/scall64-o32.S

···
 	PTR	sys_creat
 	PTR	sys_link
 	PTR	sys_unlink			/* 4010 */
-	PTR	sys32_execve
+	PTR	compat_sys_execve
 	PTR	sys_chdir
 	PTR	compat_sys_time
 	PTR	sys_mknod

arch/mips/kernel/syscall.c

···
 	               parent_tidptr, child_tidptr);
 }
 
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname((const char __user *) (long)regs.regs[4]);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-	error = do_execve(filename->name,
-			  (const char __user *const __user *) (long)regs.regs[5],
-	                  (const char __user *const __user *) (long)regs.regs[6],
-			  &regs);
-	putname(filename);
-
-out:
-	return error;
-}
-
 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
 {
 	struct thread_info *ti = task_thread_info(current);
···
 asmlinkage void bad_stack(void)
 {
 	do_exit(SIGSEGV);
-}
-
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-int kernel_execve(const char *filename,
-		  const char *const argv[],
-		  const char *const envp[])
-{
-	register unsigned long __a0 asm("$4") = (unsigned long) filename;
-	register unsigned long __a1 asm("$5") = (unsigned long) argv;
-	register unsigned long __a2 asm("$6") = (unsigned long) envp;
-	register unsigned long __a3 asm("$7");
-	unsigned long __v0;
-
-	__asm__ volatile ("					\n"
-	"	.set	noreorder				\n"
-	"	li	$2, %5		# __NR_execve		\n"
-	"	syscall						\n"
-	"	move	%0, $2					\n"
-	"	.set	reorder					\n"
-	: "=&r" (__v0), "=r" (__a3)
-	: "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
-	: "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
-	  "memory");
-
-	if (__a3 == 0)
-		return __v0;
-
-	return -__v0;
 }

arch/mn10300/Kconfig

···
 	select HAVE_NMI_WATCHDOG if MN10300_WD_TIMER
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 	select MODULES_USE_ELF_RELA
 
 config AM33_2

arch/mn10300/include/asm/unistd.h

···
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
 #define __ARCH_WANT_SYS_EXECVE
-#define __ARCH_WANT_KERNEL_EXECVE
 
 /*
  * "Conditional" syscalls

arch/mn10300/kernel/entry.S

···
 	mov	(REG_D0,fp),d0
 	mov	(REG_A0,fp),a0
 	calls	(a0)
-	jmp	sys_exit
-
-ENTRY(ret_from_kernel_execve)
-	add	-12,d0	/* pt_regs -> frame */
-	mov	d0,sp
-	GET_THREAD_INFO a2
 	clr	d0
+	mov	d0,(REG_D0,fp)
 	jmp	syscall_exit
 
 ###############################################################################

arch/openrisc/Kconfig

···
 	select GENERIC_STRNCPY_FROM_USER
 	select GENERIC_STRNLEN_USER
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 
 config MMU
 	def_bool y

arch/openrisc/include/uapi/asm/unistd.h

···
 
 #define sys_mmap2 sys_mmap_pgoff
 
+#define __ARCH_WANT_SYS_EXECVE
+
 #include <asm-generic/unistd.h>
 
 #define __NR_or1k_atomic __NR_arch_specific_syscall

arch/openrisc/kernel/entry.S

···
 	l.jal	schedule_tail
 	 l.nop
 
+	/* Check if we are a kernel thread */
+	l.sfeqi	r20,0
+	l.bf	1f
+	 l.nop
+
+	/* ...we are a kernel thread so invoke the requested callback */
+	l.jalr	r20
+	 l.or	r3,r22,r0
+
+1:
 	/* _syscall_returns expect r11 to contain return value */
 	l.lwz	r11,PT_GPR11(r1)
 
···
 
 	l.j	_syscall_return
 	 l.nop
-
-/* Since syscalls don't save call-clobbered registers, the args to
- * kernel_thread_helper will need to be passed through callee-saved
- * registers and copied to the parameter registers when the thread
- * begins running.
- *
- * See arch/openrisc/kernel/process.c:
- * The args are passed as follows:
- *   arg1 (r3) : passed in r20
- *   arg2 (r4) : passed in r22
- */
-
-ENTRY(_kernel_thread_helper)
-	l.or	r3,r20,r0
-	l.or	r4,r22,r0
-	l.movhi	r31,hi(kernel_thread_helper)
-	l.ori	r31,r31,lo(kernel_thread_helper)
-	l.jr	r31
-	 l.nop
-
 
 /* ========================================================[ switch ] === */
 
···
 	/* Unwind stack to pre-switch state */
 	l.addi  r1,r1,(INT_FRAME_SIZE)
 
-	/* Return via the link-register back to where we 'came from', where that can be
-	 * either schedule() or return_from_fork()... */
+	/* Return via the link-register back to where we 'came from', where
+	 * that may be either schedule(), ret_from_fork(), or
+	 * ret_from_kernel_thread().  If we are returning to a new thread,
+	 * we are expected to have set up the arg to schedule_tail already,
+	 * hence we do so here unconditionally:
+	 */
+	l.lwz   r3,TI_STACK(r3)		/* Load 'prev' as schedule_tail arg */
 	l.jr	r9
 	 l.nop
 
···
 	l.ori	r29,r29,lo(_sys_fork)
 	l.j	_fork_save_extra_regs_and_call
 	 l.addi	r3,r1,0
-
-ENTRY(sys_execve)
-	l.j	_sys_execve
-	 l.addi	r6,r1,0
 
 ENTRY(sys_sigaltstack)
 	l.j	_sys_sigaltstack

arch/openrisc/kernel/process.c

···
  */
 extern asmlinkage void ret_from_fork(void);
 
+/*
+ * copy_thread
+ * @clone_flags: flags
+ * @usp: user stack pointer or fn for kernel thread
+ * @arg: arg to fn for kernel thread; always NULL for userspace thread
+ * @p: the newly created task
+ * @regs: CPU context to copy for userspace thread; always NULL for kthread
+ *
+ * At the top of a newly initialized kernel stack are two stacked pt_reg
+ * structures.  The first (topmost) is the userspace context of the thread.
+ * The second is the kernelspace context of the thread.
+ *
+ * A kernel thread will not be returning to userspace, so the topmost pt_regs
+ * struct can be uninitialized; it _does_ need to exist, though, because
+ * a kernel thread can become a userspace thread by doing a kernel_execve, in
+ * which case the topmost context will be initialized and used for 'returning'
+ * to userspace.
+ *
+ * The second pt_reg struct needs to be initialized to 'return' to
+ * ret_from_fork.  A kernel thread will need to set r20 to the address of
+ * a function to call into (with arg in r22); userspace threads need to set
+ * r20 to NULL in which case ret_from_fork will just continue a return to
+ * userspace.
+ *
+ * A kernel thread 'fn' may return; this is effectively what happens when
+ * kernel_execve is called.  In that case, the userspace pt_regs must have
+ * been initialized (which kernel_execve takes care of, see start_thread
+ * below); ret_from_fork will then continue its execution causing the
+ * 'kernel thread' to return to userspace as a userspace thread.
+ */
+
 int
 copy_thread(unsigned long clone_flags, unsigned long usp,
-	    unsigned long unused, struct task_struct *p, struct pt_regs *regs)
+	    unsigned long arg, struct task_struct *p, struct pt_regs *regs)
 {
-	struct pt_regs *childregs;
+	struct pt_regs *userregs;
 	struct pt_regs *kregs;
 	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
-	struct thread_info *ti;
 	unsigned long top_of_kernel_stack;
 
 	top_of_kernel_stack = sp;
 
 	p->set_child_tid = p->clear_child_tid = NULL;
 
-	/* Copy registers */
-	/* redzone */
-	sp -= STACK_FRAME_OVERHEAD;
+	/* Locate userspace context on stack... */
+	sp -= STACK_FRAME_OVERHEAD;	/* redzone */
 	sp -= sizeof(struct pt_regs);
-	childregs = (struct pt_regs *)sp;
+	userregs = (struct pt_regs *) sp;
 
-	/* Copy parent registers */
-	*childregs = *regs;
-
-	if ((childregs->sr & SPR_SR_SM) == 1) {
-		/* for kernel thread, set `current_thread_info'
-		 * and stackptr in new task
-		 */
-		childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
-		childregs->gpr[10] = (unsigned long)task_thread_info(p);
-	} else {
-		childregs->sp = usp;
-	}
-
-	childregs->gpr[11] = 0;	/* Result from fork() */
-
-	/*
-	 * The way this works is that at some point in the future
-	 * some task will call _switch to switch to the new task.
-	 * That will pop off the stack frame created below and start
-	 * the new task running at ret_from_fork.  The new task will
-	 * do some house keeping and then return from the fork or clone
-	 * system call, using the stack frame created above.
-	 */
-	/* redzone */
-	sp -= STACK_FRAME_OVERHEAD;
+	/* ...and kernel context */
+	sp -= STACK_FRAME_OVERHEAD;	/* redzone */
 	sp -= sizeof(struct pt_regs);
 	kregs = (struct pt_regs *)sp;
 
-	ti = task_thread_info(p);
-	ti->ksp = sp;
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(kregs, 0, sizeof(struct pt_regs));
+		kregs->gpr[20] = usp; /* fn, kernel thread */
+		kregs->gpr[22] = arg;
+	} else {
+		*userregs = *regs;
 
-	/* kregs->sp must store the location of the 'pre-switch' kernel stack
-	 * pointer... for a newly forked process, this is simply the top of
-	 * the kernel stack.
+		userregs->sp = usp;
+		userregs->gpr[11] = 0;	/* Result from fork() */
+
+		kregs->gpr[20] = 0;	/* Userspace thread */
+	}
+
+	/*
+	 * _switch wants the kernel stack page in pt_regs->sp so that it
+	 * can restore it to thread_info->ksp... see _switch for details.
 	 */
 	kregs->sp = top_of_kernel_stack;
-	kregs->gpr[3] = (unsigned long)current;	/* arg to schedule_tail */
-	kregs->gpr[10] = (unsigned long)task_thread_info(p);
 	kregs->gpr[9] = (unsigned long)ret_from_fork;
+
+	task_thread_info(p)->ksp = (unsigned long)kregs;
 
 	return 0;
 }
···
  */
 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
 {
-	unsigned long sr = regs->sr & ~SPR_SR_SM;
+	unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM;
 
 	set_fs(USER_DS);
-	memset(regs->gpr, 0, sizeof(regs->gpr));
+	memset(regs, 0, sizeof(struct pt_regs));
 
 	regs->pc = pc;
 	regs->sr = sr;
 	regs->sp = sp;
-
-/*	printk("start thread, ksp = %lx\n", current_thread_info()->ksp);*/
 }
 
 /* Fill in the fpu structure for a core dump.  */
···
 	dest[35] = 0;
 }
 
-extern void _kernel_thread_helper(void);
-
-void __noreturn kernel_thread_helper(int (*fn) (void *), void *arg)
-{
-	do_exit(fn(arg));
-}
-
-/*
- * Create a kernel thread.
- */
-int kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-
-	regs.gpr[20] = (unsigned long)fn;
-	regs.gpr[22] = (unsigned long)arg;
-	regs.sr = mfspr(SPR_SR);
-	regs.pc = (unsigned long)_kernel_thread_helper;
-
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
-		       0, &regs, 0, NULL, NULL);
-}
-
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage long _sys_execve(const char __user *name,
-			    const char __user * const __user *argv,
-			    const char __user * const __user *envp,
-			    struct pt_regs *regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname(name);
-	error = PTR_ERR(filename);
-
-	if (IS_ERR(filename))
-		goto out;
-
-	error = do_execve(filename->name, argv, envp, regs);
-	putname(filename);
-
-out:
-	return error;
-}
-
 unsigned long get_wchan(struct task_struct *p)
 {
 	/* TODO */
 
 	return 0;
-}
-
-int kernel_execve(const char *filename, char *const argv[], char *const envp[])
-{
-	register long __res asm("r11") = __NR_execve;
-	register long __a asm("r3") = (long)(filename);
-	register long __b asm("r4") = (long)(argv);
-	register long __c asm("r5") = (long)(envp);
-	__asm__ volatile ("l.sys 1"
-			  : "=r" (__res), "=r"(__a), "=r"(__b), "=r"(__c)
-			  : "0"(__res), "1"(__a), "2"(__b), "3"(__c)
-			  : "r6", "r7", "r8", "r12", "r13", "r15",
-			    "r17", "r19", "r21", "r23", "r25", "r27",
-			    "r29", "r31");
-	__asm__ volatile ("l.nop");
-	return __res;
 }

arch/parisc/Kconfig

···
 	select GENERIC_STRNCPY_FROM_USER
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 
 	help
 	  The PA-RISC microprocessor is designed by Hewlett-Packard and used

arch/parisc/include/asm/unistd.h

···
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
 #define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_SYS_EXECVE
 
 #endif /* __ASSEMBLY__ */
 

arch/parisc/kernel/entry.S

···
 	.import		do_cpu_irq_mask,code
 
 	/*
-	 * r26 = function to be called
-	 * r25 = argument to pass in
-	 * r24 = flags for do_fork()
-	 *
-	 * Kernel threads don't ever return, so they don't need
-	 * a true register context. We just save away the arguments
-	 * for copy_thread/ret_ to properly set up the child.
-	 */
-
-#define CLONE_VM 0x100	/* Must agree with <linux/sched.h> */
-#define CLONE_UNTRACED 0x00800000
-
-	.import do_fork
-ENTRY(__kernel_thread)
-	STREG	%r2, -RP_OFFSET(%r30)
-
-	copy	%r30, %r1
-	ldo	PT_SZ_ALGN(%r30),%r30
-#ifdef CONFIG_64BIT
-	/* Yo, function pointers in wide mode are little structs... -PB */
-	ldd	24(%r26), %r2
-	STREG	%r2, PT_GR27(%r1)	/* Store childs %dp */
-	ldd	16(%r26), %r26
-
-	STREG	%r22, PT_GR22(%r1)	/* save r22 (arg5) */
-	copy	%r0, %r22		/* user_tid */
-#endif
-	STREG	%r26, PT_GR26(%r1)  /* Store function & argument for child */
-	STREG	%r25, PT_GR25(%r1)
-	ldil	L%CLONE_UNTRACED, %r26
-	ldo	CLONE_VM(%r26), %r26   /* Force CLONE_VM since only init_mm */
-	or	%r26, %r24, %r26      /* will have kernel mappings.	 */
-	ldi	1, %r25			/* stack_start, signals kernel thread */
-	stw	%r0, -52(%r30)	     	/* user_tid */
-#ifdef CONFIG_64BIT
-	ldo	-16(%r30),%r29		/* Reference param save area */
-#endif
-	BL	do_fork, %r2
-	copy	%r1, %r24		/* pt_regs */
-
-	/* Parent Returns here */
-
-	LDREG	-PT_SZ_ALGN-RP_OFFSET(%r30), %r2
-	ldo	-PT_SZ_ALGN(%r30), %r30
-	bv	%r0(%r2)
-	nop
-ENDPROC(__kernel_thread)
-
-	/*
 	 * Child Returns here
 	 *
-	 * copy_thread moved args from temp save area set up above
-	 * into task save area.
+	 * copy_thread moved args into task save area.
 	 */
 
 ENTRY(ret_from_kernel_thread)
···
 	BL	schedule_tail, %r2
 	nop
 
-	LDREG	TI_TASK-THREAD_SZ_ALGN(%r30), %r1
+	LDREG	TI_TASK-THREAD_SZ_ALGN-FRAME_SIZE(%r30), %r1
 	LDREG	TASK_PT_GR25(%r1), %r26
 #ifdef CONFIG_64BIT
 	LDREG	TASK_PT_GR27(%r1), %r27
-	LDREG	TASK_PT_GR22(%r1), %r22
 #endif
 	LDREG	TASK_PT_GR26(%r1), %r1
 	ble	0(%sr7, %r1)
 	copy	%r31, %r2
-
-#ifdef CONFIG_64BIT
-	ldo	-16(%r30),%r29		/* Reference param save area */
-	loadgp				/* Thread could have been in a module */
-#endif
-#ifndef CONFIG_64BIT
-	b	sys_exit
-#else
-	load32	sys_exit, %r1
-	bv	%r0(%r1)
-#endif
-	ldi	0, %r26
-ENDPROC(ret_from_kernel_thread)
-
-	.import	sys_execve, code
-ENTRY(__execve)
-	copy	%r2, %r15
-	copy	%r30, %r16
-	ldo	PT_SZ_ALGN(%r30), %r30
-	STREG	%r26, PT_GR26(%r16)
-	STREG	%r25, PT_GR25(%r16)
-	STREG	%r24, PT_GR24(%r16)
-#ifdef CONFIG_64BIT
-	ldo	-16(%r30),%r29		/* Reference param save area */
-#endif
-	BL	sys_execve, %r2
-	copy	%r16, %r26
-
-	cmpib,=,n 0,%r28,intr_return    /* forward */
-
-	/* yes, this will trap and die. */
-	copy	%r15, %r2
-	copy	%r16, %r30
-	bv	%r0(%r2)
+	b	finish_child_return
 	nop
-ENDPROC(__execve)
+ENDPROC(ret_from_kernel_thread)
 
 
 	/*
···
 	LDREG	TI_TASK-THREAD_SZ_ALGN-FRAME_SIZE(%r30), %r1
 	ldo	TASK_REGS(%r1),%r1
 	reg_save %r1
-	mfctl	%cr27, %r3
-	STREG	%r3, PT_CR27(%r1)
-
-	STREG	%r2,-RP_OFFSET(%r30)
-	ldo	FRAME_SIZE(%r30),%r30
-#ifdef CONFIG_64BIT
-	ldo	-16(%r30),%r29		/* Reference param save area */
-#endif
-
-	/* These are call-clobbered registers and therefore
-	   also syscall-clobbered (we hope). */
-	STREG	%r2,PT_GR19(%r1)	/* save for child */
-	STREG	%r30,PT_GR21(%r1)
+	mfctl	%cr27, %r28
+	STREG	%r28, PT_CR27(%r1)
 
 	LDREG	PT_GR30(%r1),%r25
 	copy	%r1,%r24
-	BL	sys_clone,%r2
+	b	sys_clone
 	ldi	SIGCHLD,%r26
-
-	LDREG	-RP_OFFSET-FRAME_SIZE(%r30),%r2
-wrapper_exit:
-	ldo	-FRAME_SIZE(%r30),%r30		/* get the stackframe */
-	LDREG	TI_TASK-THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1
-	ldo	TASK_REGS(%r1),%r1	 /* get pt regs */
-
-	LDREG	PT_CR27(%r1), %r3
-	mtctl	%r3, %cr27
-	reg_restore %r1
-
-	/* strace expects syscall # to be preserved in r20 */
-	ldi	__NR_fork,%r20
-	bv %r0(%r2)
-	STREG	%r20,PT_GR20(%r1)
 ENDPROC(sys_fork_wrapper)
 
 	/* Set the return value for the child */
 ENTRY(child_return)
 	BL	schedule_tail, %r2
 	nop
+finish_child_return:
+	LDREG	TI_TASK-THREAD_SZ_ALGN-FRAME_SIZE(%r30), %r1
+	ldo	TASK_REGS(%r1),%r1	 /* get pt regs */
 
-	LDREG	TI_TASK-THREAD_SZ_ALGN-FRAME_SIZE-FRAME_SIZE(%r30), %r1
-	LDREG	TASK_PT_GR19(%r1),%r2
-	b	wrapper_exit
+	LDREG	PT_CR27(%r1), %r3
+	mtctl	%r3, %cr27
+	reg_restore %r1
+	b	syscall_exit
 	copy	%r0,%r28
 ENDPROC(child_return)
 
···
 	LDREG	TI_TASK-THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1
 	ldo	TASK_REGS(%r1),%r1	/* get pt regs */
 	reg_save %r1
-	mfctl	%cr27, %r3
-	STREG	%r3, PT_CR27(%r1)
-
-	STREG	%r2,-RP_OFFSET(%r30)
-	ldo	FRAME_SIZE(%r30),%r30
-#ifdef CONFIG_64BIT
-	ldo	-16(%r30),%r29		/* Reference param save area */
-#endif
-
-	/* WARNING - Clobbers r19 and r21, userspace must save these! */
-	STREG	%r2,PT_GR19(%r1)	/* save for child */
-	STREG	%r30,PT_GR21(%r1)
-	BL	sys_clone,%r2
+	mfctl	%cr27, %r28
+	STREG	%r28, PT_CR27(%r1)
+	b	sys_clone
 	copy	%r1,%r24
-
-	b	wrapper_exit
-	LDREG	-RP_OFFSET-FRAME_SIZE(%r30),%r2
 ENDPROC(sys_clone_wrapper)
 
 
···
 	LDREG	TI_TASK-THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1
 	ldo	TASK_REGS(%r1),%r1	/* get pt regs */
 	reg_save %r1
-	mfctl	%cr27, %r3
-	STREG	%r3, PT_CR27(%r1)
+	mfctl	%cr27, %r28
+	STREG	%r28, PT_CR27(%r1)
 
-	STREG	%r2,-RP_OFFSET(%r30)
-	ldo	FRAME_SIZE(%r30),%r30
-#ifdef CONFIG_64BIT
-	ldo	-16(%r30),%r29		/* Reference param save area */
-#endif
-
-	STREG	%r2,PT_GR19(%r1)	/* save for child */
-	STREG	%r30,PT_GR21(%r1)
-
-	BL	sys_vfork,%r2
+	b	sys_vfork
 	copy	%r1,%r26
-
-	b	wrapper_exit
-	LDREG	-RP_OFFSET-FRAME_SIZE(%r30),%r2
 ENDPROC(sys_vfork_wrapper)
 
 	
-	.macro  execve_wrapper execve
-	LDREG	TI_TASK-THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1
-	ldo	TASK_REGS(%r1),%r1	/* get pt regs */
-
-	/*
-	 * Do we need to save/restore r3-r18 here?
-	 * I don't think so. why would new thread need old
-	 * threads registers?
-	 */
-
-	/* %arg0 - %arg3 are already saved for us. */
-
-	STREG %r2,-RP_OFFSET(%r30)
-	ldo FRAME_SIZE(%r30),%r30
-#ifdef CONFIG_64BIT
-	ldo	-16(%r30),%r29		/* Reference param save area */
-#endif
-	BL \execve,%r2
-	copy %r1,%arg0
-
-	ldo -FRAME_SIZE(%r30),%r30
-	LDREG -RP_OFFSET(%r30),%r2
-
-	/* If exec succeeded we need to load the args */
-
-	ldo -1024(%r0),%r1
-	cmpb,>>= %r28,%r1,error_\execve
-	copy %r2,%r19
-
-error_\execve:
-	bv %r0(%r19)
-	nop
-	.endm
-
-	.import sys_execve
-ENTRY(sys_execve_wrapper)
-	execve_wrapper sys_execve
-ENDPROC(sys_execve_wrapper)
-
-#ifdef CONFIG_64BIT
-	.import sys32_execve
-ENTRY(sys32_execve_wrapper)
-	execve_wrapper sys32_execve
-ENDPROC(sys32_execve_wrapper)
-#endif
-
 ENTRY(sys_rt_sigreturn_wrapper)
 	LDREG	TI_TASK-THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r26
 	ldo	TASK_REGS(%r26),%r26	/* get pt regs */

arch/parisc/kernel/process.c

···
 
 #include <asm/io.h>
 #include <asm/asm-offsets.h>
+#include <asm/assembly.h>
 #include <asm/pdc.h>
 #include <asm/pdc_chassis.h>
 #include <asm/pgalloc.h>
···
 EXPORT_SYMBOL(pm_power_off);
 
 /*
- * Create a kernel thread
- */
-
-extern pid_t __kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-
-	/*
-	 * FIXME: Once we are sure we don't need any debug here,
-	 *	  kernel_thread can become a #define.
-	 */
-
-	return __kernel_thread(fn, arg, flags);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/*
  * Free current thread data structures etc..
  */
 void exit_thread(void)
···
 
 int
 copy_thread(unsigned long clone_flags, unsigned long usp,
-	    unsigned long unused,	/* in ia64 this is "user_stack_size" */
-	    struct task_struct * p, struct pt_regs * pregs)
+	    unsigned long arg,
+	    struct task_struct *p, struct pt_regs *pregs)
 {
 	struct pt_regs * cregs = &(p->thread.regs);
 	void *stack = task_stack_page(p);
···
 #ifdef CONFIG_HPUX
 	extern void * const hpux_child_return;
 #endif
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(cregs, 0, sizeof(struct pt_regs));
+		if (!usp) /* idle thread */
+			return 0;
 
-	*cregs = *pregs;
-
-	/* Set the return value for the child.  Note that this is not
-           actually restored by the syscall exit path, but we put it
-           here for consistency in case of signals. */
-	cregs->gr[28] = 0; /* child */
-
-	/*
-	 * We need to differentiate between a user fork and a
-	 * kernel fork. We can't use user_mode, because the
-	 * the syscall path doesn't save iaoq. Right now
-	 * We rely on the fact that kernel_thread passes
-	 * in zero for usp.
-	 */
-	if (usp == 1) {
 		/* kernel thread */
-		cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN;
 		/* Must exit via ret_from_kernel_thread in order
 		 * to call schedule_tail()
 		 */
+		cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 		cregs->kpc = (unsigned long) &ret_from_kernel_thread;
 		/*
 		 * Copy function and argument to be called from
 		 * ret_from_kernel_thread.
 		 */
 #ifdef CONFIG_64BIT
-		cregs->gr[27] = pregs->gr[27];
+		cregs->gr[27] = ((unsigned long *)usp)[3];
+		cregs->gr[26] = ((unsigned long *)usp)[2];
+#else
+		cregs->gr[26] = usp;
 #endif
-		cregs->gr[26] = pregs->gr[26];
-		cregs->gr[25] = pregs->gr[25];
+		cregs->gr[25] = arg;
 	} else {
 		/* user thread */
-		/*
-		 * Note that the fork wrappers are responsible
-		 * for setting gr[21].
-		 */
-
-		/* Use same stack depth as parent */
-		cregs->ksp = (unsigned long)stack
-			+ (pregs->gr[21] & (THREAD_SIZE - 1));
 		cregs->gr[30] = usp;
+		cregs->ksp = (unsigned long)stack + THREAD_SZ_ALGN + FRAME_SIZE;
 		if (personality(p->personality) == PER_HPUX) {
 #ifdef CONFIG_HPUX
 			cregs->kpc = (unsigned long) &hpux_child_return;
···
 		}
 		/* Setup thread TLS area from the 4th parameter in clone */
 		if (clone_flags & CLONE_SETTLS)
-		  cregs->cr27 = pregs->gr[23];
-	
+			cregs->cr27 = pregs->gr[23];
 	}
 
 	return 0;
···
 unsigned long thread_saved_pc(struct task_struct *t)
 {
 	return t->thread.regs.kpc;
-}
-
-/*
- * sys_execve() executes a new program.
- */
-
-asmlinkage int sys_execve(struct pt_regs *regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname((const char __user *) regs->gr[26]);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-	error = do_execve(filename->name,
-			  (const char __user *const __user *) regs->gr[25],
-			  (const char __user *const __user *) regs->gr[24],
-			  regs);
-	putname(filename);
-out:
-
-	return error;
-}
-
-extern int __execve(const char *filename,
-		    const char *const argv[],
-		    const char *const envp[], struct task_struct *task);
-int kernel_execve(const char *filename,
-		  const char *const argv[],
-		  const char *const envp[])
-{
-	return __execve(filename, argv, envp, current);
 }
 
 unsigned long

arch/parisc/kernel/sys_parisc32.c

···
 #define DBG(x)
 #endif
 
-/*
- * sys32_execve() executes a new program.
- */
-
-asmlinkage int sys32_execve(struct pt_regs *regs)
-{
-	int error;
-	struct filename *filename;
-
-	DBG(("sys32_execve(%p) r26 = 0x%lx\n", regs, regs->gr[26]));
-	filename = getname((const char __user *) regs->gr[26]);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-	error = compat_do_execve(filename->name, compat_ptr(regs->gr[25]),
-				 compat_ptr(regs->gr[24]), regs);
-	putname(filename);
-out:
-
-	return error;
-}
-
 asmlinkage long sys32_unimplemented(int r26, int r25, int r24, int r23,
 	int r22, int r21, int r20)
 {

arch/parisc/kernel/syscall_table.S

···
 	ENTRY_SAME(creat)
 	ENTRY_SAME(link)
 	ENTRY_SAME(unlink)		/* 10 */
-	ENTRY_DIFF(execve_wrapper)
+	ENTRY_COMP(execve)
 	ENTRY_SAME(chdir)
 	/* See comments in kernel/time.c!!! Maybe we don't need this? */
 	ENTRY_COMP(time)

arch/powerpc/Kconfig

···
 	select GENERIC_KERNEL_THREAD
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_EXECVE
 
 config EARLY_PRINTK
 	bool

arch/powerpc/include/asm/unistd.h

···
 #define __ARCH_WANT_COMPAT_SYS_SENDFILE
 #endif
 #define __ARCH_WANT_SYS_EXECVE
-#define __ARCH_WANT_KERNEL_EXECVE
 
 /*
  * "Conditional" syscalls

arch/powerpc/kernel/entry_32.S

···
 	PPC440EP_ERR42
 	blrl
 	li	r3,0
-	b	do_exit		# no return
-
-	.globl	__ret_from_kernel_execve
-__ret_from_kernel_execve:
-	addi	r1,r3,-STACK_FRAME_OVERHEAD
 	b	ret_from_syscall
 
 /* Traced system call support */

arch/powerpc/kernel/entry_64.S

···
 _GLOBAL(ret_from_kernel_thread)
 	bl	.schedule_tail
 	REST_NVGPRS(r1)
-	REST_GPR(2,r1)
+	ld	r14, 0(r14)
 	mtlr	r14
 	mr	r3,r15
 	blrl
 	li	r3,0
-	b	.do_exit	# no return
-
-_GLOBAL(__ret_from_kernel_execve)
-	addi	r1,r3,-STACK_FRAME_OVERHEAD
-	li	r10,1
-	std	r10,SOFTE(r1)
 	b	syscall_exit
 
 	.section	".toc","aw"

arch/powerpc/kernel/process.c

···
 	/* Copy registers */
 	sp -= sizeof(struct pt_regs);
 	childregs = (struct pt_regs *) sp;
-	if (!regs) {
-		/* for kernel thread, set `current' and stackptr in new task */
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		struct thread_info *ti = (void *)task_stack_page(p);
 		memset(childregs, 0, sizeof(struct pt_regs));
 		childregs->gpr[1] = sp + sizeof(struct pt_regs);
-#ifdef CONFIG_PPC64
-		childregs->gpr[14] = *(unsigned long *)usp;
-		childregs->gpr[2] = ((unsigned long *)usp)[1],
-		clear_tsk_thread_flag(p, TIF_32BIT);
-#else
 		childregs->gpr[14] = usp;	/* function */
-		childregs->gpr[2] = (unsigned long) p;
+#ifdef CONFIG_PPC64
+		clear_tsk_thread_flag(p, TIF_32BIT);
+		childregs->softe = 1;
 #endif
 		childregs->gpr[15] = arg;
 		p->thread.regs = NULL;	/* no user register state */
+		ti->flags |= _TIF_RESTOREALL;
 		f = ret_from_kernel_thread;
 	} else {
 		CHECK_FULL_REGS(regs);
 		*childregs = *regs;
-		childregs->gpr[1] = usp;
+		if (usp)
+			childregs->gpr[1] = usp;
 		p->thread.regs = childregs;
 		childregs->gpr[3] = 0;  /* Result from fork() */
 		if (clone_flags & CLONE_SETTLS) {
···
 	return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
 }
 
-#define TRUNC_PTR(x)	((typeof(x))(((unsigned long)(x)) & 0xffffffff))
-
 int sys_clone(unsigned long clone_flags, unsigned long usp,
 	      int __user *parent_tidp, void __user *child_threadptr,
 	      int __user *child_tidp, int p6,
 	      struct pt_regs *regs)
 {
-	CHECK_FULL_REGS(regs);
-	if (usp == 0)
-		usp = regs->gpr[1];	/* stack pointer for child */
-#ifdef CONFIG_PPC64
-	if (is_32bit_task()) {
-		parent_tidp = TRUNC_PTR(parent_tidp);
-		child_tidp = TRUNC_PTR(child_tidp);
-	}
-#endif
  	return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 }
 
···
 	     unsigned long p4, unsigned long p5, unsigned long p6,
 	     struct pt_regs *regs)
 {
-	CHECK_FULL_REGS(regs);
-	return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
+	return do_fork(SIGCHLD, 0, regs, 0, NULL, NULL);
 }
 
 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
 	      unsigned long p4, unsigned long p5, unsigned long p6,
 	      struct pt_regs *regs)
 {
-	CHECK_FULL_REGS(regs);
-	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
+	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 0,
 			regs, 0, NULL, NULL);
-}
-
-void __ret_from_kernel_execve(struct pt_regs *normal)
-__noreturn;
-
-void ret_from_kernel_execve(struct pt_regs *normal)
-{
-	set_thread_flag(TIF_RESTOREALL);
-	__ret_from_kernel_execve(normal);
 }
 
 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,

arch/s390/Kconfig

···
 	select KTIME_SCALAR if 32BIT
 	select HAVE_ARCH_SECCOMP_FILTER
 	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
 

arch/s390/include/asm/unistd.h

···
 #   define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
 # endif
 #define __ARCH_WANT_SYS_EXECVE
-#define __ARCH_WANT_KERNEL_EXECVE
 
 /*
  * "Conditional" syscalls

arch/s390/kernel/entry.S

···
 	la	%r11,STACK_FRAME_OVERHEAD(%r15)
 	l	%r12,__LC_THREAD_INFO
 	l	%r13,__LC_SVC_NEW_PSW+4
+	l	%r1,BASED(.Lschedule_tail)
+	basr	%r14,%r1		# call schedule_tail
+	TRACE_IRQS_ON
+	ssm	__LC_SVC_NEW_PSW	# reenable interrupts
 	tm	__PT_PSW+1(%r11),0x01	# forking a kernel thread ?
-	je	1f
-	l	%r1,BASED(.Lschedule_tail)
-	basr	%r14,%r1		# call schedule_tail
-	TRACE_IRQS_ON
-	ssm	__LC_SVC_NEW_PSW	# reenable interrupts
-	j	sysc_tracenogo
-
-1:	# it's a kernel thread
-	st	%r15,__PT_R15(%r11)	# store stack pointer for new kthread
-	l	%r1,BASED(.Lschedule_tail)
-	basr	%r14,%r1		# call schedule_tail
-	TRACE_IRQS_ON
-	ssm	__LC_SVC_NEW_PSW	# reenable interrupts
-	lm	%r9,%r11,__PT_R9(%r11)	# load gprs
+	jne	sysc_tracenogo
+	# it's a kernel thread
+	lm	%r9,%r10,__PT_R9(%r11)	# load gprs
 ENTRY(kernel_thread_starter)
 	la	%r2,0(%r10)
 	basr	%r14,%r9
-	la	%r2,0
-	br	%r11			# do_exit
-
-#
-# kernel_execve function needs to deal with pt_regs that is not
-# at the usual place
-#
-ENTRY(ret_from_kernel_execve)
-	ssm	__LC_PGM_NEW_PSW	# disable I/O and ext. interrupts
-	lr	%r15,%r2
-	lr	%r11,%r2
-	ahi	%r15,-STACK_FRAME_OVERHEAD
-	xc	__SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
-	l	%r12,__LC_THREAD_INFO
-	ssm	__LC_SVC_NEW_PSW	# reenable interrupts
-	j	sysc_return
+	j	sysc_tracenogo
 
 /*
  * Program check handler routine

arch/s390/kernel/entry64.S

···
 ENTRY(ret_from_fork)
 	la	%r11,STACK_FRAME_OVERHEAD(%r15)
 	lg	%r12,__LC_THREAD_INFO
+	brasl	%r14,schedule_tail
+	TRACE_IRQS_ON
+	ssm	__LC_SVC_NEW_PSW	# reenable interrupts
 	tm	__PT_PSW+1(%r11),0x01	# forking a kernel thread ?
-	je	1f
-	brasl	%r14,schedule_tail
-	TRACE_IRQS_ON
-	ssm	__LC_SVC_NEW_PSW	# reenable interrupts
-	j	sysc_tracenogo
-1:	# it's a kernel thread
-	stg	%r15,__PT_R15(%r11)	# store stack pointer for new kthread
-	brasl	%r14,schedule_tail
-	TRACE_IRQS_ON
-	ssm	__LC_SVC_NEW_PSW	# reenable interrupts
-	lmg	%r9,%r11,__PT_R9(%r11)	# load gprs
+	jne	sysc_tracenogo
+	# it's a kernel thread
+	lmg	%r9,%r10,__PT_R9(%r11)	# load gprs
 ENTRY(kernel_thread_starter)
 	la	%r2,0(%r10)
 	basr	%r14,%r9
-	la	%r2,0
-	br	%r11			# do_exit
-
-ENTRY(ret_from_kernel_execve)
-	ssm	__LC_PGM_NEW_PSW	# disable I/O and ext. interrupts
-	lgr	%r15,%r2
-	lgr	%r11,%r2
-	aghi	%r15,-STACK_FRAME_OVERHEAD
-	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
-	lg	%r12,__LC_THREAD_INFO
-	ssm	__LC_SVC_NEW_PSW	# reenable interrupts
-	j	sysc_return
+	j	sysc_tracenogo
 
 /*
  * Program check handler routine

arch/score/Kconfig

···
        select GENERIC_CLOCKEVENTS
        select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_REL
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 
 choice
 	prompt "System type"

arch/score/include/asm/processor.h

···
  */
 extern void (*cpu_wait)(void);
 
-extern long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 extern unsigned long thread_saved_pc(struct task_struct *tsk);
 extern void start_thread(struct pt_regs *regs,
 			unsigned long pc, unsigned long sp);

arch/score/include/asm/syscalls.h

···
 #define _ASM_SCORE_SYSCALLS_H
 
 asmlinkage long score_clone(struct pt_regs *regs);
-asmlinkage long score_execve(struct pt_regs *regs);
 asmlinkage long score_sigaltstack(struct pt_regs *regs);
 asmlinkage long score_rt_sigreturn(struct pt_regs *regs);
 

arch/score/include/asm/unistd.h

···
 #define __ARCH_WANT_SYSCALL_NO_FLAGS
 #define __ARCH_WANT_SYSCALL_OFF_T
 #define __ARCH_WANT_SYSCALL_DEPRECATED
+#define __ARCH_WANT_SYS_EXECVE
 
 #include <asm-generic/unistd.h>

arch/score/kernel/entry.S

···
 	nop
 #endif
 
+ENTRY(ret_from_kernel_thread)
+	bl	schedule_tail			# r4=struct task_struct *prev
+	nop
+	mv	r4, r13
+	brl	r12
+	j	syscall_exit
+
 ENTRY(ret_from_fork)
 	bl	schedule_tail			# r4=struct task_struct *prev
 
···
 	ldi	r9, 1			# set error flag
 	sw	r9, [r0, PT_R7]
 	j	syscall_return
-
-ENTRY(sys_execve)
-	mv	r4, r0
-	la	r8, score_execve
-	br	r8
 
 ENTRY(sys_clone)
 	mv	r4, r0

arch/score/kernel/process.c

···
 }
 
 void ret_from_fork(void);
+void ret_from_kernel_thread(void);
 
 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
 {
···
  * set up the kernel stack and exception frames for a new process
  */
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-		unsigned long unused,
+		unsigned long arg,
 		struct task_struct *p, struct pt_regs *regs)
 {
 	struct thread_info *ti = task_thread_info(p);
 	struct pt_regs *childregs = task_pt_regs(p);
 
-	p->set_child_tid = NULL;
-	p->clear_child_tid = NULL;
-
-	*childregs = *regs;
-	childregs->regs[7] = 0;		/* Clear error flag */
-	childregs->regs[4] = 0;		/* Child gets zero as return value */
-	regs->regs[4] = p->pid;
-
-	if (childregs->cp0_psr & 0x8) {	/* test kernel fork or user fork */
-		childregs->regs[0] = usp;		/* user fork */
+	p->thread.reg0 = (unsigned long) childregs;
+	if (unlikely(!regs)) {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		p->thread->reg12 = usp;
+		p->thread->reg13 = arg;
+		p->thread.reg3 = (unsigned long) ret_from_kernel_thread;
 	} else {
-		childregs->regs[28] = (unsigned long) ti; /* kernel fork */
-		childregs->regs[0] = (unsigned long) childregs;
+		*childregs = *regs;
+		childregs->regs[7] = 0;		/* Clear error flag */
+		childregs->regs[4] = 0;		/* Child gets zero as return value */
+		childregs->regs[0] = usp;	/* user fork */
+		regs->regs[4] = p->pid;		/* WTF? */
+		p->thread.reg3 = (unsigned long) ret_from_fork;
 	}
 
-	p->thread.reg0 = (unsigned long) childregs;
-	p->thread.reg3 = (unsigned long) ret_from_fork;
 	p->thread.cp0_psr = 0;
 
 	return 0;
···
 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
 {
 	return 1;
-}
-
-static void __noreturn
-kernel_thread_helper(void *unused0, int (*fn)(void *),
-		 void *arg, void *unused1)
-{
-	do_exit(fn(arg));
-}
-
-/*
- * Create a kernel thread.
- */
-long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-
-	regs.regs[6] = (unsigned long) arg;
-	regs.regs[5] = (unsigned long) fn;
-	regs.cp0_epc = (unsigned long) kernel_thread_helper;
-	regs.cp0_psr = (regs.cp0_psr & ~(0x1|0x4|0x8)) | \
-			((regs.cp0_psr & 0x3) << 2);
-
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, \
-			0, &regs, 0, NULL, NULL);
 }
 
 unsigned long thread_saved_pc(struct task_struct *tsk)

arch/score/kernel/sys_score.c

···
 	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
 			regs->regs[0], regs, 0, NULL, NULL);
 }
-
-/*
- * sys_execve() executes a new program.
- * This is called indirectly via a small wrapper
- */
-asmlinkage long
-score_execve(struct pt_regs *regs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname((char __user*)regs->regs[4]);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		return error;
-
-	error = do_execve(filename->name,
-			  (const char __user *const __user *)regs->regs[5],
-			  (const char __user *const __user *)regs->regs[6],
-			  regs);
-
-	putname(filename);
-	return error;
-}
-
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-asmlinkage
-int kernel_execve(const char *filename,
-		  const char *const argv[],
-		  const char *const envp[])
-{
-	register unsigned long __r4 asm("r4") = (unsigned long) filename;
-	register unsigned long __r5 asm("r5") = (unsigned long) argv;
-	register unsigned long __r6 asm("r6") = (unsigned long) envp;
-	register unsigned long __r7 asm("r7");
-
-	__asm__ __volatile__ ("	\n"
-		"ldi	r27, %5		\n"
-		"syscall		\n"
-		"mv	%0, r4		\n"
-		"mv	%1, r7		\n"
-		: "=&r" (__r4), "=r" (__r7)
-		: "r" (__r4), "r" (__r5), "r" (__r6), "i" (__NR_execve)
-		: "r8", "r9", "r10", "r11", "r22", "r23", "r24", "r25",
-		  "r26", "r27", "memory");
-
-	if (__r7 == 0)
-		return __r4;
-
-	return -__r4;
-}

arch/sh/Kconfig

···
 	select GENERIC_STRNLEN_USER
 	select HAVE_MOD_ARCH_SPECIFIC if DWARF_UNWINDER
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 	help
 	  The SuperH is a RISC processor targeted for use in embedded systems
 	  and consumer electronics; it was also used in the Sega Dreamcast

arch/sh/include/asm/processor_32.h

···
 /* Free all resources held by a thread. */
 extern void release_thread(struct task_struct *);
 
-/*
- * create a kernel thread without removing it from tasklists
- */
-extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
-
 /* Copy and release all segment info associated with a VM */
 #define copy_segments(p, mm)	do { } while(0)
 #define release_segments(mm)	do { } while(0)

arch/sh/include/asm/processor_64.h

···
 
 /* Free all resources held by a thread. */
 extern void release_thread(struct task_struct *);
-/*
- * create a kernel thread without removing it from tasklists
- */
-extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
-
 
 /* Copy and release all segment info associated with a VM */
 #define copy_segments(p, mm)	do { } while (0)

arch/sh/include/asm/syscalls_32.h

···
 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 			 unsigned long r6, unsigned long r7,
 			 struct pt_regs __regs);
-asmlinkage int sys_execve(const char __user *ufilename,
-			  const char __user *const __user *uargv,
-			  const char __user *const __user *uenvp,
-			  unsigned long r7, struct pt_regs __regs);
 asmlinkage int sys_sigsuspend(old_sigset_t mask);
 asmlinkage int sys_sigaction(int sig, const struct old_sigaction __user *act,
 			     struct old_sigaction __user *oact);

arch/sh/include/asm/syscalls_64.h

···
 			 unsigned long r4, unsigned long r5,
 			 unsigned long r6, unsigned long r7,
 			 struct pt_regs *pregs);
-asmlinkage int sys_execve(const char *ufilename, char **uargv,
-			  char **uenvp, unsigned long r5,
-			  unsigned long r6, unsigned long r7,
-			  struct pt_regs *pregs);
 
 /* Misc syscall related bits */
 asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs);

arch/sh/include/asm/unistd.h

···
 # define __ARCH_WANT_SYS_SIGPENDING
 # define __ARCH_WANT_SYS_SIGPROCMASK
 # define __ARCH_WANT_SYS_RT_SIGACTION
+# define __ARCH_WANT_SYS_EXECVE
 
 /*
  * "Conditional" syscalls

arch/sh/kernel/Makefile

···
 	   machvec.o nmi_debug.o process.o				\
 	   process_$(BITS).o ptrace.o ptrace_$(BITS).o			\
 	   reboot.o return_address.o					\
-	   setup.o signal_$(BITS).o sys_sh.o sys_sh$(BITS).o		\
+	   setup.o signal_$(BITS).o sys_sh.o 				\
 	   syscalls_$(BITS).o time.o topology.o traps.o			\
 	   traps_$(BITS).o unwinder.o
 
···
 obj-$(CONFIG_HAS_IOPORT)	+= ioport.o
 endif
 
+obj-$(CONFIG_SUPERH32)		+= sys_sh32.o
 obj-y				+= cpu/
 obj-$(CONFIG_VSYSCALL)		+= vsyscall/
 obj-$(CONFIG_SMP)		+= smp.o

arch/sh/kernel/cpu/sh5/entry.S

···
 	pta	ret_from_syscall, tr0
 	blink	tr0, ZERO
 
+.global	ret_from_kernel_thread
+ret_from_kernel_thread:
+
+	movi	schedule_tail,r5
+	ori	r5, 1, r5
+	ptabs	r5, tr0
+	blink	tr0, LINK
+
+	ld.q	SP, FRAME_R(2), r2
+	ld.q	SP, FRAME_R(3), r3
+	ptabs	r3, tr0
+	blink	tr0, LINK
+
+	ld.q	SP, FRAME_S(FSPC), r2
+	addi	r2, 4, r2		/* Move PC, being pre-execution event */
+	st.q	SP, FRAME_S(FSPC), r2
+	pta	ret_from_syscall, tr0
+	blink	tr0, ZERO
+
 syscall_allowed:
 	/* Use LINK to deflect the exit point, default is syscall_ret */
 	pta	syscall_ret, tr0

arch/sh/kernel/entry-common.S

···
 	 mov	r0, r4
 	bra	syscall_exit
 	 nop
+
+	.align	2
+	.globl	ret_from_kernel_thread
+ret_from_kernel_thread:
+	mov.l	1f, r8
+	jsr	@r8
+	 mov	r0, r4
+	mov.l	@(OFF_R5,r15), r5   ! fn
+	jsr	@r5
+	 mov.l	@(OFF_R4,r15), r4   ! arg
+	bra	syscall_exit
+	 nop
+
 	.align	2
 1:	.long	schedule_tail
 

arch/sh/kernel/process_32.c

···
 	show_code(regs);
 }
 
-/*
- * Create a kernel thread
- */
-__noreturn void kernel_thread_helper(void *arg, int (*fn)(void *))
-{
-	do_exit(fn(arg));
-}
-
-/* Don't use this in BL=1(cli).  Or else, CPU resets! */
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-	struct pt_regs regs;
-	int pid;
-
-	memset(&regs, 0, sizeof(regs));
-	regs.regs[4] = (unsigned long)arg;
-	regs.regs[5] = (unsigned long)fn;
-
-	regs.pc = (unsigned long)kernel_thread_helper;
-	regs.sr = SR_MD;
-#if defined(CONFIG_SH_FPU)
-	regs.sr |= SR_FD;
-#endif
-
-	/* Ok, create the new process.. */
-	pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
-		      &regs, 0, NULL, NULL);
-
-	return pid;
-}
-EXPORT_SYMBOL(kernel_thread);
-
 void start_thread(struct pt_regs *regs, unsigned long new_pc,
 		  unsigned long new_sp)
 {
···
 EXPORT_SYMBOL(dump_fpu);
 
 asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-		unsigned long unused,
+		unsigned long arg,
 		struct task_struct *p, struct pt_regs *regs)
 {
 	struct thread_info *ti = task_thread_info(p);
···
 	}
 #endif
 
-	childregs = task_pt_regs(p);
-	*childregs = *regs;
+	memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
 
-	if (user_mode(regs)) {
-		childregs->regs[15] = usp;
-		ti->addr_limit = USER_DS;
-	} else {
-		childregs->regs[15] = (unsigned long)childregs;
+	childregs = task_pt_regs(p);
+	p->thread.sp = (unsigned long) childregs;
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		p->thread.pc = (unsigned long) ret_from_kernel_thread;
+		childregs->regs[4] = arg;
+		childregs->regs[5] = usp;
+		childregs->sr = SR_MD;
+#if defined(CONFIG_SH_FPU)
+		childregs->sr |= SR_FD;
+#endif
 		ti->addr_limit = KERNEL_DS;
 		ti->status &= ~TS_USEDFPU;
 		p->fpu_counter = 0;
+		return 0;
 	}
+	*childregs = *regs;
+
+	childregs->regs[15] = usp;
+	ti->addr_limit = USER_DS;
 
 	if (clone_flags & CLONE_SETTLS)
 		childregs->gbr = childregs->regs[0];
 
 	childregs->regs[0] = 0; /* Set return value for child */
-
-	p->thread.sp = (unsigned long) childregs;
 	p->thread.pc = (unsigned long) ret_from_fork;
-
-	memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
-
 	return 0;
 }
 
···
 	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
 		       0, NULL, NULL);
-}
-
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage int sys_execve(const char __user *ufilename,
-			  const char __user *const __user *uargv,
-			  const char __user *const __user *uenvp,
-			  unsigned long r7, struct pt_regs __regs)
-{
-	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
-	int error;
-	struct filename *filename;
-
-	filename = getname(ufilename);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-
-	error = do_execve(filename->name, uargv, uenvp, regs);
-	putname(filename);
-out:
-	return error;
 }
 
 unsigned long get_wchan(struct task_struct *p)

arch/sh/kernel/process_64.c

···
 }
 
 /*
- * Create a kernel thread
- */
-__noreturn void kernel_thread_helper(void *arg, int (*fn)(void *))
-{
-	do_exit(fn(arg));
-}
-
-/*
- * This is the mechanism for creating a new kernel thread.
- *
- * NOTE! Only a kernel-only process(ie the swapper or direct descendants
- * who haven't done an "execve()") should use this: it will work within
- * a system call from a "real" process, but the process memory space will
- * not be freed until both the parent and the child have exited.
- */
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-	regs.regs[2] = (unsigned long)arg;
-	regs.regs[3] = (unsigned long)fn;
-
-	regs.pc = (unsigned long)kernel_thread_helper;
-	regs.sr = (1 << 30);
-
-	/* Ok, create the new process.. */
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
-		      &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/*
  * Free current thread data structures etc..
  */
 void exit_thread(void)
···
 EXPORT_SYMBOL(dump_fpu);
 
 asmlinkage void ret_from_fork(void);
+asmlinkage void ret_from_kernel_thread(void);
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-		unsigned long unused,
+		unsigned long arg,
 		struct task_struct *p, struct pt_regs *regs)
 {
 	struct pt_regs *childregs;
 
 #ifdef CONFIG_SH_FPU
-	if(last_task_used_math == current) {
+	/* can't happen for a kernel thread */
+	if (last_task_used_math == current) {
 		enable_fpu();
 		save_fpu(current);
 		disable_fpu();
···
 #endif
 	/* Copy from sh version */
 	childregs = (struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1;
+	p->thread.sp = (unsigned long) childregs;
 
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(childregs, 0, sizeof(struct pt_regs));
+		childregs->regs[2] = (unsigned long)arg;
+		childregs->regs[3] = (unsigned long)fn;
+		childregs->sr = (1 << 30); /* not user_mode */
+		childregs->sr |= SR_FD; /* Invalidate FPU flag */
+		p->thread.pc = (unsigned long) ret_from_kernel_thread;
+		return 0;
+	}
 	*childregs = *regs;
 
 	/*
···
 	 * 32-bit wide and context switch must take care
 	 * of NEFF sign extension.
 	 */
-	if (user_mode(regs)) {
-		childregs->regs[15] = neff_sign_extend(usp);
-		p->thread.uregs = childregs;
-	} else {
-		childregs->regs[15] =
-			neff_sign_extend((unsigned long)task_stack_page(p) +
-					 THREAD_SIZE);
-	}
+	childregs->regs[15] = neff_sign_extend(usp);
+	p->thread.uregs = childregs;
 
 	childregs->regs[9] = 0; /* Set return value for child */
 	childregs->sr |= SR_FD; /* Invalidate FPU flag */
 
-	p->thread.sp = (unsigned long) childregs;
 	p->thread.pc = (unsigned long) ret_from_fork;
 
 	return 0;
···
 			 struct pt_regs *pregs)
 {
 	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, pregs->regs[15], pregs, 0, 0, 0);
-}
-
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage int sys_execve(const char *ufilename, char **uargv,
-			  char **uenvp, unsigned long r5,
-			  unsigned long r6, unsigned long r7,
-			  struct pt_regs *pregs)
-{
-	int error;
-	struct filename *filename;
-
-	filename = getname((char __user *)ufilename);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-
-	error = do_execve(filename->name,
-			  (const char __user *const __user *)uargv,
-			  (const char __user *const __user *)uenvp,
-			  pregs);
-	putname(filename);
-out:
-	return error;
 }
 
 #ifdef CONFIG_FRAME_POINTER

arch/sh/kernel/sys_sh32.c

···
 				(u64)len0 << 32 | len1,	advice);
 #endif
 }
-
-#if defined(CONFIG_CPU_SH2) || defined(CONFIG_CPU_SH2A)
-#define SYSCALL_ARG3	"trapa #0x23"
-#else
-#define SYSCALL_ARG3	"trapa #0x13"
-#endif
-
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-int kernel_execve(const char *filename,
-		  const char *const argv[],
-		  const char *const envp[])
-{
-	register long __sc0 __asm__ ("r3") = __NR_execve;
-	register long __sc4 __asm__ ("r4") = (long) filename;
-	register long __sc5 __asm__ ("r5") = (long) argv;
-	register long __sc6 __asm__ ("r6") = (long) envp;
-	__asm__ __volatile__ (SYSCALL_ARG3 : "=z" (__sc0)
-			: "0" (__sc0), "r" (__sc4), "r" (__sc5), "r" (__sc6)
-			: "memory");
-	return __sc0;
-}

arch/sh/kernel/sys_sh64.c

···
-/*
- * arch/sh/kernel/sys_sh64.c
- *
- * Copyright (C) 2000, 2001  Paolo Alberelli
- *
- * This file contains various random system calls that
- * have a non-standard calling sequence on the Linux/SH5
- * platform.
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- */
-#include <linux/errno.h>
-#include <linux/rwsem.h>
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/smp.h>
-#include <linux/sem.h>
-#include <linux/msg.h>
-#include <linux/shm.h>
-#include <linux/stat.h>
-#include <linux/mman.h>
-#include <linux/file.h>
-#include <linux/syscalls.h>
-#include <linux/ipc.h>
-#include <asm/uaccess.h>
-#include <asm/ptrace.h>
-#include <asm/unistd.h>
-
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-int kernel_execve(const char *filename,
-		  const char *const argv[],
-		  const char *const envp[])
-{
-	register unsigned long __sc0 __asm__ ("r9") = ((0x13 << 16) | __NR_execve);
-	register unsigned long __sc2 __asm__ ("r2") = (unsigned long) filename;
-	register unsigned long __sc3 __asm__ ("r3") = (unsigned long) argv;
-	register unsigned long __sc4 __asm__ ("r4") = (unsigned long) envp;
-	__asm__ __volatile__ ("trapa	%1 !\t\t\t execve(%2,%3,%4)"
-	: "=r" (__sc0)
-	: "r" (__sc0), "r" (__sc2), "r" (__sc3), "r" (__sc4) );
-	__asm__ __volatile__ ("!dummy	%0 %1 %2 %3"
-	: : "r" (__sc0), "r" (__sc2), "r" (__sc3), "r" (__sc4) : "memory");
-	return __sc0;
-}

arch/sparc/Kconfig

···
 	select GENERIC_STRNCPY_FROM_USER
 	select GENERIC_STRNLEN_USER
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 
 config SPARC32
 	def_bool !64BIT

arch/sparc/include/asm/processor_32.h

···
 
 /* Free all resources held by a thread. */
 #define release_thread(tsk)		do { } while(0)
-extern pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 
 extern unsigned long get_wchan(struct task_struct *);
 

arch/sparc/include/asm/processor_64.h

···
 #ifndef __ASSEMBLY__
 
 #include <linux/types.h>
+#include <asm/fpumacro.h>
 
 /* Return saved PC of a blocked thread. */
 struct task_struct;
···
 	: \
 	: "r" (regs), "r" (sp - sizeof(struct reg_window) - STACK_BIAS), \
 	  "i" ((const unsigned long)(&((struct pt_regs *)0)->u_regs[0]))); \
+	fprs_write(0);	\
+	current_thread_info()->xfsr[0] = 0;	\
+	current_thread_info()->fpsaved[0] = 0;	\
+	regs->tstate &= ~TSTATE_PEF;	\
 } while (0)
 
 #define start_thread32(regs, pc, sp) \
···
 	: \
 	: "r" (regs), "r" (sp - sizeof(struct reg_window32)), \
 	  "i" ((const unsigned long)(&((struct pt_regs *)0)->u_regs[0]))); \
+	fprs_write(0);	\
+	current_thread_info()->xfsr[0] = 0;	\
+	current_thread_info()->fpsaved[0] = 0;	\
+	regs->tstate &= ~TSTATE_PEF;	\
 } while (0)
 
 /* Free all resources held by a thread. */
 #define release_thread(tsk)		do { } while (0)
-
-extern pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 
 extern unsigned long get_wchan(struct task_struct *task);
 

arch/sparc/include/asm/ptrace.h

···
 #define arch_ptrace_stop(exit_code, info) \
 	synchronize_user_stack()
 
+#define current_pt_regs() \
+	((struct pt_regs *)((unsigned long)current_thread_info() + THREAD_SIZE) - 1)
+
 struct global_reg_snapshot {
 	unsigned long		tstate;
 	unsigned long		tpc;
···
 
 extern union global_cpu_snapshot global_cpu_snapshot[NR_CPUS];
 
-#define force_successful_syscall_return()	    \
-do {	current_thread_info()->syscall_noerror = 1; \
-} while (0)
+#define force_successful_syscall_return() set_thread_noerror(1)
 #define user_mode(regs) (!((regs)->tstate & TSTATE_PRIV))
 #define instruction_pointer(regs) ((regs)->tpc)
 #define instruction_pointer_set(regs, val) ((regs)->tpc = (val))
···
 
 #define arch_ptrace_stop(exit_code, info) \
 	synchronize_user_stack()
+
+#define current_pt_regs() \
+	((struct pt_regs *)((unsigned long)current_thread_info() + THREAD_SIZE) - 1)
 
 #define user_mode(regs) (!((regs)->psr & PSR_PS))
 #define instruction_pointer(regs) ((regs)->pc)

arch/sparc/include/asm/switch_to_64.h

···
 	/* If you are tempted to conditionalize the following */	\
 	/* so that ASI is only written if it changes, think again. */	\
 	__asm__ __volatile__("wr %%g0, %0, %%asi"			\
-	: : "r" (__thread_flag_byte_ptr(task_thread_info(next))[TI_FLAG_BYTE_CURRENT_DS]));\
+	: : "r" (task_thread_info(next)->current_ds));\
 	trap_block[current_thread_info()->cpu].thread =			\
 		task_thread_info(next);					\
 	__asm__ __volatile__(						\

arch/sparc/include/asm/syscalls.h

···
 				     struct pt_regs *regs,
 				     unsigned long stack_size);
 
-extern asmlinkage int sparc_execve(struct pt_regs *regs);
-
 #endif /* _SPARC64_SYSCALLS_H */

arch/sparc/include/asm/thread_info_64.h

···
 #define TI_FLAG_FAULT_CODE_SHIFT	56
 #define TI_FLAG_BYTE_WSTATE		1
 #define TI_FLAG_WSTATE_SHIFT		48
-#define TI_FLAG_BYTE_CWP		2
-#define TI_FLAG_CWP_SHIFT		40
-#define TI_FLAG_BYTE_CURRENT_DS		3
-#define TI_FLAG_CURRENT_DS_SHIFT	32
-#define TI_FLAG_BYTE_FPDEPTH		4
-#define TI_FLAG_FPDEPTH_SHIFT		24
+#define TI_FLAG_BYTE_NOERROR		2
+#define TI_FLAG_BYTE_NOERROR_SHIFT	40
+#define TI_FLAG_BYTE_FPDEPTH		3
+#define TI_FLAG_FPDEPTH_SHIFT		32
+#define TI_FLAG_BYTE_CWP		4
+#define TI_FLAG_CWP_SHIFT		24
 #define TI_FLAG_BYTE_WSAVED		5
 #define TI_FLAG_WSAVED_SHIFT		16
 
···
 	struct exec_domain	*exec_domain;
 	int			preempt_count;	/* 0 => preemptable, <0 => BUG */
 	__u8			new_child;
-	__u8			syscall_noerror;
+	__u8			current_ds;
 	__u16			cpu;
 
 	unsigned long		*utraps;
···
 #define TI_FAULT_CODE	(TI_FLAGS + TI_FLAG_BYTE_FAULT_CODE)
 #define TI_WSTATE	(TI_FLAGS + TI_FLAG_BYTE_WSTATE)
 #define TI_CWP		(TI_FLAGS + TI_FLAG_BYTE_CWP)
-#define TI_CURRENT_DS	(TI_FLAGS + TI_FLAG_BYTE_CURRENT_DS)
 #define TI_FPDEPTH	(TI_FLAGS + TI_FLAG_BYTE_FPDEPTH)
 #define TI_WSAVED	(TI_FLAGS + TI_FLAG_BYTE_WSAVED)
+#define TI_SYS_NOERROR	(TI_FLAGS + TI_FLAG_BYTE_NOERROR)
 #define TI_FPSAVED	0x00000010
 #define TI_KSP		0x00000018
 #define TI_FAULT_ADDR	0x00000020
···
 #define TI_EXEC_DOMAIN	0x00000030
 #define TI_PRE_COUNT	0x00000038
 #define TI_NEW_CHILD	0x0000003c
-#define TI_SYS_NOERROR	0x0000003d
+#define TI_CURRENT_DS	0x0000003d
 #define TI_CPU		0x0000003e
 #define TI_UTRAPS	0x00000040
 #define TI_REG_WINDOW	0x00000048
···
 #define INIT_THREAD_INFO(tsk)				\
 {							\
 	.task		=	&tsk,			\
-	.flags		= ((unsigned long)ASI_P) << TI_FLAG_CURRENT_DS_SHIFT,	\
+	.current_ds	=	ASI_P,			\
 	.exec_domain	=	&default_exec_domain,	\
 	.preempt_count	=	INIT_PREEMPT_COUNT,	\
 	.restart_block	= {				\
···
 #define set_thread_wstate(val)		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_WSTATE] = (val))
 #define get_thread_cwp()		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_CWP])
 #define set_thread_cwp(val)		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_CWP] = (val))
-#define get_thread_current_ds()		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_CURRENT_DS])
-#define set_thread_current_ds(val)	(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_CURRENT_DS] = (val))
+#define get_thread_noerror()		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_NOERROR])
+#define set_thread_noerror(val)		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_NOERROR] = (val))
 #define get_thread_fpdepth()		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_FPDEPTH])
 #define set_thread_fpdepth(val)		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_FPDEPTH] = (val))
 #define get_thread_wsaved()		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_WSAVED])
 #define set_thread_wsaved(val)		(__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_WSAVED] = (val))
-
 #endif /* !(__ASSEMBLY__) */
 
 /*

arch/sparc/include/asm/uaccess_64.h

···
 #define VERIFY_READ	0
 #define VERIFY_WRITE	1
 
-#define get_fs() ((mm_segment_t) { get_thread_current_ds() })
+#define get_fs() ((mm_segment_t){(current_thread_info()->current_ds)})
 #define get_ds() (KERNEL_DS)
 
 #define segment_eq(a,b)  ((a).seg == (b).seg)
 
 #define set_fs(val)								\
 do {										\
-	set_thread_current_ds((val).seg);					\
+	current_thread_info()->current_ds =(val).seg;				\
 	__asm__ __volatile__ ("wr %%g0, %0, %%asi" : : "r" ((val).seg));	\
 } while(0)
 

arch/sparc/include/asm/unistd.h

···
 #define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
 #define __ARCH_WANT_COMPAT_SYS_SENDFILE
 #endif
+#define __ARCH_WANT_SYS_EXECVE
 
 /*
  * "Conditional" syscalls

arch/sparc/kernel/entry.S

···
 	call	c_sys_nis_syscall
 	 mov	%l5, %o7
 
-	.align	4
-	.globl	sys_execve
-sys_execve:
-	mov	%o7, %l5
-	add	%sp, STACKFRAME_SZ, %o0		! pt_regs *regs arg
-	call	sparc_execve
-	 mov	%l5, %o7
-
-	.globl	sunos_execv
 sunos_execv:
-	st	%g0, [%sp + STACKFRAME_SZ + PT_I2]
-
-	call	sparc_execve
-	 add	%sp, STACKFRAME_SZ, %o0
-
-	b	ret_sys_call
-	 ld	[%sp + STACKFRAME_SZ + PT_I0], %o0
+	.globl	sunos_execv
+	b	sys_execve
+	 clr	%i2
 
 	.align	4
 	.globl	sys_sparc_pipe
···
         .align  4
 linux_sparc_ni_syscall:
 	sethi   %hi(sys_ni_syscall), %l7
-	b       syscall_is_too_hard
+	b       do_syscall
 	 or     %l7, %lo(sys_ni_syscall), %l7
-
-linux_fast_syscall:
-	andn	%l7, 3, %l7
-	mov	%i0, %o0
-	mov	%i1, %o1
-	mov 	%i2, %o2
-	jmpl	%l7 + %g0, %g0
-	 mov	%i3, %o3
 
 linux_syscall_trace:
 	add	%sp, STACKFRAME_SZ, %o0
···
 	b	ret_sys_call
 	 ld	[%sp + STACKFRAME_SZ + PT_I0], %o0
 
+	.globl	ret_from_kernel_thread
+ret_from_kernel_thread:
+	call	schedule_tail
+	 ld	[%g3 + TI_TASK], %o0
+	ld	[%sp + STACKFRAME_SZ + PT_G1], %l0
+	call	%l0
+	 ld	[%sp + STACKFRAME_SZ + PT_G2], %o0
+	rd	%psr, %l1
+	ld	[%sp + STACKFRAME_SZ + PT_PSR], %l0
+	andn	%l0, PSR_CWP, %l0
+	nop
+	and	%l1, PSR_CWP, %l1
+	or	%l0, %l1, %l0
+	st	%l0, [%sp + STACKFRAME_SZ + PT_PSR]
+	b	ret_sys_call
+	 mov	0, %o0
+
 	/* Linux native system calls enter here... */
 	.align	4
 	.globl	linux_sparc_syscall
···
 	bgeu	linux_sparc_ni_syscall
 	 sll	%g1, 2, %l4
 	ld	[%l7 + %l4], %l7
-	andcc	%l7, 1, %g0
-	bne	linux_fast_syscall
-	 /* Just do first insn from SAVE_ALL in the delay slot */
 
-syscall_is_too_hard:
+do_syscall:
 	SAVE_ALL_HEAD
 	 rd	%wim, %l3
 

arch/sparc/kernel/etrap_64.S

···
 		rdpr	%wstate, %g2
 		wrpr	%g0, 0, %canrestore
 		sll	%g2, 3, %g2
+
+		/* Set TI_SYS_FPDEPTH to 1 and clear TI_SYS_NOERROR.  */
 		mov	1, %l5
-		stb	%l5, [%l6 + TI_FPDEPTH]
+		sth	%l5, [%l6 + TI_SYS_NOERROR]
 
 		wrpr	%g3, 0, %otherwin
 		wrpr	%g2, 0, %wstate
···
 		add	%l6, TI_FPSAVED + 1, %l4
 		srl	%l5, 1, %l3
 		add	%l5, 2, %l5
-		stb	%l5, [%l6 + TI_FPDEPTH]
+
+		/* Set TI_SYS_FPDEPTH to %l5 and clear TI_SYS_NOERROR.  */
+		sth	%l5, [%l6 + TI_SYS_NOERROR]
 		ba,pt	%xcc, 2b
 		 stb	%g0, [%l4 + %l3]
 		nop

arch/sparc/kernel/process_32.c

···
  * XXX See comment above sys_vfork in sparc64. todo.
  */
 extern void ret_from_fork(void);
+extern void ret_from_kernel_thread(void);
 
 int copy_thread(unsigned long clone_flags, unsigned long sp,
-		unsigned long unused,
+		unsigned long arg,
 		struct task_struct *p, struct pt_regs *regs)
 {
 	struct thread_info *ti = task_thread_info(p);
···
 	}
 
 	/*
-	 *  p->thread_info         new_stack   childregs
-	 *  !                      !           !             {if(PSR_PS) }
-	 *  V                      V (stk.fr.) V  (pt_regs)  { (stk.fr.) }
-	 *  +----- - - - - - ------+===========+============={+==========}+
+	 *  p->thread_info         new_stack   childregs stack bottom
+	 *  !                      !           !             !
+	 *  V                      V (stk.fr.) V  (pt_regs)  V
+	 *  +----- - - - - - ------+===========+=============+
 	 */
 	new_stack = task_stack_page(p) + THREAD_SIZE;
-	if (regs->psr & PSR_PS)
-		new_stack -= STACKFRAME_SZ;
 	new_stack -= STACKFRAME_SZ + TRACEREG_SZ;
-	memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
 	childregs = (struct pt_regs *) (new_stack + STACKFRAME_SZ);
 
 	/*
···
 	 * Thus, kpsr|=PSR_PIL.
 	 */
 	ti->ksp = (unsigned long) new_stack;
+	p->thread.kregs = childregs;
+
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		extern int nwindows;
+		unsigned long psr;
+		memset(new_stack, 0, STACKFRAME_SZ + TRACEREG_SZ);
+		p->thread.flags |= SPARC_FLAG_KTHREAD;
+		p->thread.current_ds = KERNEL_DS;
+		ti->kpc = (((unsigned long) ret_from_kernel_thread) - 0x8);
+		childregs->u_regs[UREG_G1] = sp; /* function */
+		childregs->u_regs[UREG_G2] = arg;
+		psr = childregs->psr = get_psr();
+		ti->kpsr = psr | PSR_PIL;
+		ti->kwim = 1 << (((psr & PSR_CWP) + 1) % nwindows);
+		return 0;
+	}
+	memcpy(new_stack, (char *)regs - STACKFRAME_SZ, STACKFRAME_SZ + TRACEREG_SZ);
+	childregs->u_regs[UREG_FP] = sp;
+	p->thread.flags &= ~SPARC_FLAG_KTHREAD;
+	p->thread.current_ds = USER_DS;
 	ti->kpc = (((unsigned long) ret_from_fork) - 0x8);
 	ti->kpsr = current->thread.fork_kpsr | PSR_PIL;
 	ti->kwim = current->thread.fork_kwim;
 
-	if(regs->psr & PSR_PS) {
-		extern struct pt_regs fake_swapper_regs;
+	if (sp != regs->u_regs[UREG_FP]) {
+		struct sparc_stackf __user *childstack;
+		struct sparc_stackf __user *parentstack;
 
-		p->thread.kregs = &fake_swapper_regs;
-		new_stack += STACKFRAME_SZ + TRACEREG_SZ;
-		childregs->u_regs[UREG_FP] = (unsigned long) new_stack;
-		p->thread.flags |= SPARC_FLAG_KTHREAD;
-		p->thread.current_ds = KERNEL_DS;
-		memcpy(new_stack, (void *)regs->u_regs[UREG_FP], STACKFRAME_SZ);
-		childregs->u_regs[UREG_G6] = (unsigned long) ti;
-	} else {
-		p->thread.kregs = childregs;
-		childregs->u_regs[UREG_FP] = sp;
-		p->thread.flags &= ~SPARC_FLAG_KTHREAD;
-		p->thread.current_ds = USER_DS;
-
-		if (sp != regs->u_regs[UREG_FP]) {
-			struct sparc_stackf __user *childstack;
-			struct sparc_stackf __user *parentstack;
-
-			/*
-			 * This is a clone() call with supplied user stack.
-			 * Set some valid stack frames to give to the child.
-			 */
-			childstack = (struct sparc_stackf __user *)
-				(sp & ~0xfUL);
-			parentstack = (struct sparc_stackf __user *)
-				regs->u_regs[UREG_FP];
+		/*
+		 * This is a clone() call with supplied user stack.
+		 * Set some valid stack frames to give to the child.
+		 */
+		childstack = (struct sparc_stackf __user *)
+			(sp & ~0xfUL);
+		parentstack = (struct sparc_stackf __user *)
+			regs->u_regs[UREG_FP];
 
 #if 0
-			printk("clone: parent stack:\n");
-			show_stackframe(parentstack);
+		printk("clone: parent stack:\n");
+		show_stackframe(parentstack);
 #endif
 
-			childstack = clone_stackframe(childstack, parentstack);
-			if (!childstack)
-				return -EFAULT;
+		childstack = clone_stackframe(childstack, parentstack);
+		if (!childstack)
+			return -EFAULT;
 
 #if 0
-			printk("clone: child stack:\n");
-			show_stackframe(childstack);
+		printk("clone: child stack:\n");
+		show_stackframe(childstack);
 #endif
 
-			childregs->u_regs[UREG_FP] = (unsigned long)childstack;
-		}
+		childregs->u_regs[UREG_FP] = (unsigned long)childstack;
 	}
 
 #ifdef CONFIG_SMP
···
 	       sizeof(struct fpq) * (32 - fpregs->pr_qcnt));
 	return 1;
 }
-
-/*
- * sparc_execve() executes a new program after the asm stub has set
- * things up for us.  This should basically do what I want it to.
- */
-asmlinkage int sparc_execve(struct pt_regs *regs)
-{
-	int error, base = 0;
-	struct filename *filename;
-
-	/* Check for indirect call. */
-	if(regs->u_regs[UREG_G1] == 0)
-		base = 1;
-
-	filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
-	error = PTR_ERR(filename);
-	if(IS_ERR(filename))
-		goto out;
-	error = do_execve(filename->name,
-			  (const char __user *const  __user *)
-			  regs->u_regs[base + UREG_I1],
-			  (const char __user *const  __user *)
-			  regs->u_regs[base + UREG_I2],
-			  regs);
-	putname(filename);
-out:
-	return error;
-}
-
-/*
- * This is the mechanism for creating a new kernel thread.
- *
- * NOTE! Only a kernel-only process(ie the swapper or direct descendants
- * who haven't done an "execve()") should use this: it will work within
- * a system call from a "real" process, but the process memory space will
- * not be freed until both the parent and the child have exited.
- */
-pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-	long retval;
-
-	__asm__ __volatile__("mov %4, %%g2\n\t"    /* Set aside fn ptr... */
-			     "mov %5, %%g3\n\t"    /* and arg. */
-			     "mov %1, %%g1\n\t"
-			     "mov %2, %%o0\n\t"    /* Clone flags. */
-			     "mov 0, %%o1\n\t"     /* usp arg == 0 */
-			     "t 0x10\n\t"          /* Linux/Sparc clone(). */
-			     "cmp %%o1, 0\n\t"
-			     "be 1f\n\t"           /* The parent, just return. */
-			     " nop\n\t"            /* Delay slot. */
-			     "jmpl %%g2, %%o7\n\t" /* Call the function. */
-			     " mov %%g3, %%o0\n\t" /* Get back the arg in delay. */
-			     "mov %3, %%g1\n\t"
-			     "t 0x10\n\t"          /* Linux/Sparc exit(). */
-			     /* Notreached by child. */
-			     "1: mov %%o0, %0\n\t" :
-			     "=r" (retval) :
-			     "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
-			     "i" (__NR_exit),  "r" (fn), "r" (arg) :
-			     "g1", "g2", "g3", "o0", "o1", "memory", "cc");
-	return retval;
-}
-EXPORT_SYMBOL(kernel_thread);
 
 unsigned long get_wchan(struct task_struct *task)
 {

arch/sparc/kernel/process_64.c

···
  * Child  -->  %o0 == parents pid, %o1 == 1
  */
 int copy_thread(unsigned long clone_flags, unsigned long sp,
-		unsigned long unused,
+		unsigned long arg,
 		struct task_struct *p, struct pt_regs *regs)
 {
 	struct thread_info *t = task_thread_info(p);
 	struct sparc_stackf *parent_sf;
 	unsigned long child_stack_sz;
 	char *child_trap_frame;
-	int kernel_thread;
-
-	kernel_thread = (regs->tstate & TSTATE_PRIV) ? 1 : 0;
-	parent_sf = ((struct sparc_stackf *) regs) - 1;
 
 	/* Calculate offset to stack_frame & pt_regs */
-	child_stack_sz = ((STACKFRAME_SZ + TRACEREG_SZ) +
-			  (kernel_thread ? STACKFRAME_SZ : 0));
+	child_stack_sz = (STACKFRAME_SZ + TRACEREG_SZ);
 	child_trap_frame = (task_stack_page(p) +
 			    (THREAD_SIZE - child_stack_sz));
-	memcpy(child_trap_frame, parent_sf, child_stack_sz);
 
-	t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) |
-				 (0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) |
-		(((regs->tstate + 1) & TSTATE_CWP) << TI_FLAG_CWP_SHIFT);
 	t->new_child = 1;
 	t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
 	t->kregs = (struct pt_regs *) (child_trap_frame +
 				       sizeof(struct sparc_stackf));
 	t->fpsaved[0] = 0;
 
-	if (kernel_thread) {
-		struct sparc_stackf *child_sf = (struct sparc_stackf *)
-			(child_trap_frame + (STACKFRAME_SZ + TRACEREG_SZ));
-
-		/* Zero terminate the stack backtrace.  */
-		child_sf->fp = NULL;
-		t->kregs->u_regs[UREG_FP] =
-		  ((unsigned long) child_sf) - STACK_BIAS;
-
-		t->flags |= ((long)ASI_P << TI_FLAG_CURRENT_DS_SHIFT);
-		t->kregs->u_regs[UREG_G6] = (unsigned long) t;
-		t->kregs->u_regs[UREG_G4] = (unsigned long) t->task;
-	} else {
-		if (t->flags & _TIF_32BIT) {
-			sp &= 0x00000000ffffffffUL;
-			regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
-		}
-		t->kregs->u_regs[UREG_FP] = sp;
-		t->flags |= ((long)ASI_AIUS << TI_FLAG_CURRENT_DS_SHIFT);
-		if (sp != regs->u_regs[UREG_FP]) {
-			unsigned long csp;
-
-			csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
-			if (!csp)
-				return -EFAULT;
-			t->kregs->u_regs[UREG_FP] = csp;
-		}
-		if (t->utraps)
-			t->utraps[0]++;
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		memset(child_trap_frame, 0, child_stack_sz);
+		__thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] = 
+			(current_pt_regs()->tstate + 1) & TSTATE_CWP;
+		t->current_ds = ASI_P;
+		t->kregs->u_regs[UREG_G1] = sp; /* function */
+		t->kregs->u_regs[UREG_G2] = arg;
+		return 0;
 	}
+
+	parent_sf = ((struct sparc_stackf *) regs) - 1;
+	memcpy(child_trap_frame, parent_sf, child_stack_sz);
+	if (t->flags & _TIF_32BIT) {
+		sp &= 0x00000000ffffffffUL;
+		regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
+	}
+	t->kregs->u_regs[UREG_FP] = sp;
+	__thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] = 
+		(regs->tstate + 1) & TSTATE_CWP;
+	t->current_ds = ASI_AIUS;
+	if (sp != regs->u_regs[UREG_FP]) {
+		unsigned long csp;
+
+		csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
+		if (!csp)
+			return -EFAULT;
+		t->kregs->u_regs[UREG_FP] = csp;
+	}
+	if (t->utraps)
+		t->utraps[0]++;
 
 	/* Set the return value for the child. */
 	t->kregs->u_regs[UREG_I0] = current->pid;
···
 
 	return 0;
 }
-
-/*
- * This is the mechanism for creating a new kernel thread.
- *
- * NOTE! Only a kernel-only process(ie the swapper or direct descendants
- * who haven't done an "execve()") should use this: it will work within
- * a system call from a "real" process, but the process memory space will
- * not be freed until both the parent and the child have exited.
- */
-pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-	long retval;
-
-	/* If the parent runs before fn(arg) is called by the child,
-	 * the input registers of this function can be clobbered.
-	 * So we stash 'fn' and 'arg' into global registers which
-	 * will not be modified by the parent.
-	 */
-	__asm__ __volatile__("mov %4, %%g2\n\t"	   /* Save FN into global */
-			     "mov %5, %%g3\n\t"	   /* Save ARG into global */
-			     "mov %1, %%g1\n\t"	   /* Clone syscall nr. */
-			     "mov %2, %%o0\n\t"	   /* Clone flags. */
-			     "mov 0, %%o1\n\t"	   /* usp arg == 0 */
-			     "t 0x6d\n\t"	   /* Linux/Sparc clone(). */
-			     "brz,a,pn %%o1, 1f\n\t" /* Parent, just return. */
-			     " mov %%o0, %0\n\t"
-			     "jmpl %%g2, %%o7\n\t"   /* Call the function. */
-			     " mov %%g3, %%o0\n\t"   /* Set arg in delay. */
-			     "mov %3, %%g1\n\t"
-			     "t 0x6d\n\t"	   /* Linux/Sparc exit(). */
-			     /* Notreached by child. */
-			     "1:" :
-			     "=r" (retval) :
-			     "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
-			     "i" (__NR_exit),  "r" (fn), "r" (arg) :
-			     "g1", "g2", "g3", "o0", "o1", "memory", "cc");
-	return retval;
-}
-EXPORT_SYMBOL(kernel_thread);
 
 typedef struct {
 	union {
···
 	return 1;
 }
 EXPORT_SYMBOL(dump_fpu);
-
-/*
- * sparc_execve() executes a new program after the asm stub has set
- * things up for us.  This should basically do what I want it to.
- */
-asmlinkage int sparc_execve(struct pt_regs *regs)
-{
-	int error, base = 0;
-	struct filename *filename;
-
-	/* User register window flush is done by entry.S */
-
-	/* Check for indirect call. */
-	if (regs->u_regs[UREG_G1] == 0)
-		base = 1;
-
-	filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-	error = do_execve(filename->name,
-			  (const char __user *const __user *)
-			  regs->u_regs[base + UREG_I1],
-			  (const char __user *const __user *)
-			  regs->u_regs[base + UREG_I2], regs);
-	putname(filename);
-	if (!error) {
-		fprs_write(0);
-		current_thread_info()->xfsr[0] = 0;
-		current_thread_info()->fpsaved[0] = 0;
-		regs->tstate &= ~TSTATE_PEF;
-	}
-out:
-	return error;
-}
 
 unsigned long get_wchan(struct task_struct *task)
 {

arch/sparc/kernel/sys_sparc32.c

···
         return ret;
 }
 
-/*
- * sparc32_execve() executes a new program after the asm stub has set
- * things up for us.  This should basically do what I want it to.
- */
-asmlinkage long sparc32_execve(struct pt_regs *regs)
-{
-	int error, base = 0;
-	struct filename *filename;
-
-	/* User register window flush is done by entry.S */
-
-	/* Check for indirect call. */
-	if ((u32)regs->u_regs[UREG_G1] == 0)
-		base = 1;
-
-	filename = getname(compat_ptr(regs->u_regs[base + UREG_I0]));
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-
-	error = compat_do_execve(filename->name,
-				 compat_ptr(regs->u_regs[base + UREG_I1]),
-				 compat_ptr(regs->u_regs[base + UREG_I2]), regs);
-
-	putname(filename);
-
-	if (!error) {
-		fprs_write(0);
-		current_thread_info()->xfsr[0] = 0;
-		current_thread_info()->fpsaved[0] = 0;
-		regs->tstate &= ~TSTATE_PEF;
-	}
-out:
-	return error;
-}
-
 #ifdef CONFIG_MODULES
 
 asmlinkage long sys32_init_module(void __user *umod, u32 len,

arch/sparc/kernel/sys_sparc_32.c

···
 	up_read(&uts_sem);
 	return err;
 }
-
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-int kernel_execve(const char *filename,
-		  const char *const argv[],
-		  const char *const envp[])
-{
-	long __res;
-	register long __g1 __asm__ ("g1") = __NR_execve;
-	register long __o0 __asm__ ("o0") = (long)(filename);
-	register long __o1 __asm__ ("o1") = (long)(argv);
-	register long __o2 __asm__ ("o2") = (long)(envp);
-	asm volatile ("t 0x10\n\t"
-		      "bcc 1f\n\t"
-		      "mov %%o0, %0\n\t"
-		      "sub %%g0, %%o0, %0\n\t"
-		      "1:\n\t"
-		      : "=r" (__res), "=&r" (__o0)
-		      : "1" (__o0), "r" (__o1), "r" (__o2), "r" (__g1)
-		      : "cc");
-	return __res;
-}

arch/sparc/kernel/sys_sparc_64.c

···
 	return ret;
 }
 
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-int kernel_execve(const char *filename,
-		  const char *const argv[],
-		  const char *const envp[])
-{
-	long __res;
-	register long __g1 __asm__ ("g1") = __NR_execve;
-	register long __o0 __asm__ ("o0") = (long)(filename);
-	register long __o1 __asm__ ("o1") = (long)(argv);
-	register long __o2 __asm__ ("o2") = (long)(envp);
-	asm volatile ("t 0x6d\n\t"
-		      "sub %%g0, %%o0, %0\n\t"
-		      "movcc %%xcc, %%o0, %0\n\t"
-		      : "=r" (__res), "=&r" (__o0)
-		      : "1" (__o0), "r" (__o1), "r" (__o2), "r" (__g1)
-		      : "cc");
-	return __res;
-}
-
 asmlinkage long sys_kern_features(void)
 {
 	return KERN_FEATURE_MIXED_MODE_STACK;

arch/sparc/kernel/syscalls.S

···
 	/* SunOS's execv() call only specifies the argv argument, the
 	 * environment settings are the same as the calling processes.
 	 */
-sys_execve:
-	sethi	%hi(sparc_execve), %g1
-	ba,pt	%xcc, execve_merge
-	 or	%g1, %lo(sparc_execve), %g1
+sys64_execve:
+	set	sys_execve, %g1
+	jmpl	%g1, %g0
+	 flushw
 
 #ifdef CONFIG_COMPAT
 sunos_execv:
-	stx	%g0, [%sp + PTREGS_OFF + PT_V9_I2]
+	mov	%g0, %o2
 sys32_execve:
-	sethi	%hi(sparc32_execve), %g1
-	or	%g1, %lo(sparc32_execve), %g1
-#endif
-
-execve_merge:
-	flushw
+	set	compat_sys_execve, %g1
 	jmpl	%g1, %g0
-	 add	%sp, PTREGS_OFF, %o0
+	 flushw
+#endif
 
 	.align	32
 sys_sparc_pipe:
···
 ret_from_syscall:
 	/* Clear current_thread_info()->new_child. */
 	stb	%g0, [%g6 + TI_NEW_CHILD]
-	ldx	[%g6 + TI_FLAGS], %l0
 	call	schedule_tail
 	 mov	%g7, %o0
+	ldx	[%sp + PTREGS_OFF + PT_V9_I0], %o0
+	brnz,pt	%o0, ret_sys_call
+	 ldx	[%g6 + TI_FLAGS], %l0
+	ldx	[%sp + PTREGS_OFF + PT_V9_G1], %l1
+	call	%l1
+	 ldx	[%sp + PTREGS_OFF + PT_V9_G2], %o0
 	ba,pt	%xcc, ret_sys_call
-	 ldx	[%sp + PTREGS_OFF + PT_V9_I0], %o0
+	 mov	0, %o0
 
 	.globl	sparc_exit
 	.type	sparc_exit,#function
···
 	ldx	[%sp + PTREGS_OFF + PT_V9_TNPC], %l1 ! pc = npc
 
 2:
-	stb	%g0, [%g6 + TI_SYS_NOERROR]
 	/* System call success, clear Carry condition code. */
 	andn	%g3, %g2, %g3
 3:

arch/sparc/kernel/systbls_64.S

···
 /*40*/	.word sys_newlstat, sys_dup, sys_sparc_pipe, sys_times, sys_nis_syscall
 	.word sys_umount, sys_setgid, sys_getgid, sys_signal, sys_geteuid
 /*50*/	.word sys_getegid, sys_acct, sys_memory_ordering, sys_nis_syscall, sys_ioctl
-	.word sys_reboot, sys_nis_syscall, sys_symlink, sys_readlink, sys_execve
+	.word sys_reboot, sys_nis_syscall, sys_symlink, sys_readlink, sys64_execve
 /*60*/	.word sys_umask, sys_chroot, sys_newfstat, sys_fstat64, sys_getpagesize
 	.word sys_msync, sys_vfork, sys_pread64, sys_pwrite64, sys_nis_syscall
 /*70*/	.word sys_nis_syscall, sys_mmap, sys_nis_syscall, sys_64_munmap, sys_mprotect

arch/sparc/kernel/traps_64.c

···
 		     TI_PRE_COUNT != offsetof(struct thread_info,
 					      preempt_count) ||
 		     TI_NEW_CHILD != offsetof(struct thread_info, new_child) ||
-		     TI_SYS_NOERROR != offsetof(struct thread_info,
-						syscall_noerror) ||
+		     TI_CURRENT_DS != offsetof(struct thread_info,
+						current_ds) ||
 		     TI_RESTART_BLOCK != offsetof(struct thread_info,
 						  restart_block) ||
 		     TI_KUNA_REGS != offsetof(struct thread_info,

arch/sparc/mm/init_64.c

···
 void prom_world(int enter)
 {
 	if (!enter)
-		set_fs((mm_segment_t) { get_thread_current_ds() });
+		set_fs(get_fs());
 
 	__asm__ __volatile__("flushw");
 }

arch/tile/Kconfig

···
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select GENERIC_CLOCKEVENTS
 	select MODULES_USE_ELF_RELA
+	select GENERIC_KERNEL_THREAD
+	select GENERIC_KERNEL_EXECVE
 
 # FIXME: investigate whether we need/want these options.
 #	select HAVE_IOREMAP_PROT

arch/tile/include/asm/compat.h

···
 struct compat_sigaction;
 struct compat_siginfo;
 struct compat_sigaltstack;
-long compat_sys_execve(const char __user *path,
-		       compat_uptr_t __user *argv,
-		       compat_uptr_t __user *envp, struct pt_regs *);
 long compat_sys_rt_sigaction(int sig, struct compat_sigaction __user *act,
 			     struct compat_sigaction __user *oact,
 			     size_t sigsetsize);
 long compat_sys_rt_sigqueueinfo(int pid, int sig,
 				struct compat_siginfo __user *uinfo);
-long compat_sys_rt_sigreturn(struct pt_regs *);
+long compat_sys_rt_sigreturn(void);
 long compat_sys_sigaltstack(const struct compat_sigaltstack __user *uss_ptr,
-			    struct compat_sigaltstack __user *uoss_ptr,
-			    struct pt_regs *);
+			    struct compat_sigaltstack __user *uoss_ptr);
 long compat_sys_truncate64(char __user *filename, u32 dummy, u32 low, u32 high);
 long compat_sys_ftruncate64(unsigned int fd, u32 dummy, u32 low, u32 high);
 long compat_sys_pread64(unsigned int fd, char __user *ubuf, size_t count,
···
 long compat_sys_sched_rr_get_interval(compat_pid_t pid,
 				      struct compat_timespec __user *interval);
 
-/* These are the intvec_64.S trampolines. */
-long _compat_sys_execve(const char __user *path,
-			const compat_uptr_t __user *argv,
-			const compat_uptr_t __user *envp);
-long _compat_sys_sigaltstack(const struct compat_sigaltstack __user *uss_ptr,
-			    struct compat_sigaltstack __user *uoss_ptr);
+/* Assembly trampoline to avoid clobbering r0. */
 long _compat_sys_rt_sigreturn(void);
 
 #endif /* _ASM_TILE_COMPAT_H */

arch/tile/include/asm/elf.h

···
 #define compat_start_thread(regs, ip, usp) do { \
 		regs->pc = ptr_to_compat_reg((void *)(ip)); \
 		regs->sp = ptr_to_compat_reg((void *)(usp)); \
+		single_step_execve();	\
 	} while (0)
 
 /*

arch/tile/include/asm/processor.h

···
 {
 	regs->pc = pc;
 	regs->sp = usp;
+	single_step_execve();
 }
 
 /* Free all resources held by a thread. */
···
 #define KSTK_TOP(task)	(task_ksp0(task) - STACK_TOP_DELTA)
 #define task_pt_regs(task) \
   ((struct pt_regs *)(task_ksp0(task) - KSTK_PTREGS_GAP) - 1)
+#define current_pt_regs()                                   \
+  ((struct pt_regs *)((stack_pointer | (THREAD_SIZE - 1)) - \
+                      (KSTK_PTREGS_GAP - 1)) - 1)
 #define task_sp(task)	(task_pt_regs(task)->sp)
 #define task_pc(task)	(task_pt_regs(task)->pc)
 /* Aliases for pc and sp (used in fs/proc/array.c) */

arch/tile/include/asm/switch_to.h

···
 /* Support function for forking a new task. */
 void ret_from_fork(void);
 
-/* Called from ret_from_fork() when a new process starts up. */
+/* Support function for forking a new kernel thread. */
+void ret_from_kernel_thread(void *fn, void *arg);
+
+/* Called from ret_from_xxx() when a new process starts up. */
 struct task_struct *sim_notify_fork(struct task_struct *prev);
 
 #endif /* !__ASSEMBLY__ */

arch/tile/include/asm/syscalls.h

···
 
 #ifndef __tilegx__
 /* mm/fault.c */
-long sys_cmpxchg_badaddr(unsigned long address, struct pt_regs *);
-long _sys_cmpxchg_badaddr(unsigned long address);
+long sys_cmpxchg_badaddr(unsigned long address);
 #endif
 
 #ifdef CONFIG_COMPAT
···
 long sys_ftruncate64(unsigned int fd, loff_t length);
 #endif
 
+/* Provide versions of standard syscalls that use current_pt_regs(). */
+long sys_clone(unsigned long clone_flags, unsigned long newsp,
+		void __user *parent_tid, void __user *child_tid);
+long sys_execve(const char __user *filename,
+		 const char __user *const __user *argv,
+		 const char __user *const __user *envp);
+long sys_rt_sigreturn(void);
+long sys_sigaltstack(const stack_t __user *, stack_t __user *);
+#define sys_clone sys_clone
+#define sys_execve sys_execve
+#define sys_rt_sigreturn sys_rt_sigreturn
+#define sys_sigaltstack sys_sigaltstack
+
 /* These are the intvec*.S trampolines. */
-long _sys_sigaltstack(const stack_t __user *, stack_t __user *);
 long _sys_rt_sigreturn(void);
 long _sys_clone(unsigned long clone_flags, unsigned long newsp,
 		void __user *parent_tid, void __user *child_tid);
-long _sys_execve(const char __user *filename,
-		 const char __user *const __user *argv,
-		 const char __user *const __user *envp);
 
 #include <asm-generic/syscalls.h>
 

arch/tile/include/asm/unistd.h

···
 #define __ARCH_WANT_SYS_LLSEEK
 #endif
 #define __ARCH_WANT_SYS_NEWFSTATAT
+#define __ARCH_WANT_SYS_EXECVE
 #include <uapi/asm/unistd.h>

arch/tile/kernel/compat.c

···
 #define compat_sys_fadvise64_64 sys32_fadvise64_64
 #define compat_sys_readahead sys32_readahead
 
-/* Call the trampolines to manage pt_regs where necessary. */
-#define compat_sys_execve _compat_sys_execve
-#define compat_sys_sigaltstack _compat_sys_sigaltstack
+/* Call the assembly trampolines where necessary. */
 #define compat_sys_rt_sigreturn _compat_sys_rt_sigreturn
+#undef sys_clone
 #define sys_clone _sys_clone
 
 /*

arch/tile/kernel/compat_signal.c

···
 }
 
 long compat_sys_sigaltstack(const struct compat_sigaltstack __user *uss_ptr,
-			    struct compat_sigaltstack __user *uoss_ptr,
-			    struct pt_regs *regs)
+			    struct compat_sigaltstack __user *uoss_ptr)
 {
 	stack_t uss, uoss;
 	int ret;
···
 	set_fs(KERNEL_DS);
 	ret = do_sigaltstack(uss_ptr ? (stack_t __user __force *)&uss : NULL,
 			     (stack_t __user __force *)&uoss,
-			     (unsigned long)compat_ptr(regs->sp));
+			     (unsigned long)compat_ptr(current_pt_regs()->sp));
 	set_fs(seg);
 	if (ret >= 0 && uoss_ptr)  {
 		if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(*uoss_ptr)) ||
···
 }
 
 /* The assembly shim for this function arranges to ignore the return value. */
-long compat_sys_rt_sigreturn(struct pt_regs *regs)
+long compat_sys_rt_sigreturn(void)
 {
+	struct pt_regs *regs = current_pt_regs();
 	struct compat_rt_sigframe __user *frame =
 		(struct compat_rt_sigframe __user *) compat_ptr(regs->sp);
 	sigset_t set;
···
 	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
 		goto badframe;
 
-	if (compat_sys_sigaltstack(&frame->uc.uc_stack, NULL, regs) != 0)
+	if (compat_sys_sigaltstack(&frame->uc.uc_stack, NULL) == -EFAULT)
 		goto badframe;
 
 	return 0;

arch/tile/kernel/entry.S

···
 	STD_ENDPROC(current_text_addr)
 
 /*
- * Implement execve().  The i386 code has a note that forking from kernel
- * space results in no copy on write until the execve, so we should be
- * careful not to write to the stack here.
- */
-STD_ENTRY(kernel_execve)
-	moveli TREG_SYSCALL_NR_NAME, __NR_execve
-	swint1
-	jrp lr
-	STD_ENDPROC(kernel_execve)
-
-/*
  * We don't run this function directly, but instead copy it to a page
  * we map into every user process.  See vdso_setup().
  *

arch/tile/kernel/intvec_32.S

···
 	}
 	STD_ENDPROC(ret_from_fork)
 
+STD_ENTRY(ret_from_kernel_thread)
+	jal     sim_notify_fork
+	jal     schedule_tail
+	FEEDBACK_REENTER(ret_from_fork)
+	{
+	 move   r0, r31
+	 jalr   r30
+	}
+	FEEDBACK_REENTER(ret_from_kernel_thread)
+	{
+	 movei  r30, 0               /* not an NMI */
+	 j      .Lresume_userspace   /* jump into middle of interrupt_return */
+	}
+	STD_ENDPROC(ret_from_kernel_thread)
+
 	/*
 	 * Code for ill interrupt.
 	 */
···
 	panic   "Unhandled interrupt %#x: PC %#lx"
 	STD_ENDPROC(bad_intr)
 
-/* Put address of pt_regs in reg and jump. */
-#define PTREGS_SYSCALL(x, reg)                          \
-	STD_ENTRY(_##x);                                \
-	{                                               \
-	 PTREGS_PTR(reg, PTREGS_OFFSET_BASE);           \
-	 j      x                                       \
-	};                                              \
-	STD_ENDPROC(_##x)
-
 /*
  * Special-case sigreturn to not write r0 to the stack on return.
  * This is technically more efficient, but it also avoids difficulties
···
 	};                                              \
 	STD_ENDPROC(_##x)
 
-PTREGS_SYSCALL(sys_execve, r3)
-PTREGS_SYSCALL(sys_sigaltstack, r2)
 PTREGS_SYSCALL_SIGRETURN(sys_rt_sigreturn, r0)
-PTREGS_SYSCALL(sys_cmpxchg_badaddr, r1)
 
-/* Save additional callee-saves to pt_regs, put address in r4 and jump. */
+/* Save additional callee-saves to pt_regs and jump to standard function. */
 STD_ENTRY(_sys_clone)
 	push_extra_callee_saves r4
 	j       sys_clone

arch/tile/kernel/intvec_64.S

···
 	}
 	STD_ENDPROC(ret_from_fork)
 
+STD_ENTRY(ret_from_kernel_thread)
+	jal     sim_notify_fork
+	jal     schedule_tail
+	FEEDBACK_REENTER(ret_from_fork)
+	{
+	 move   r0, r31
+	 jalr   r30
+	}
+	FEEDBACK_REENTER(ret_from_kernel_thread)
+	{
+	 movei  r30, 0               /* not an NMI */
+	 j      .Lresume_userspace   /* jump into middle of interrupt_return */
+	}
+	STD_ENDPROC(ret_from_kernel_thread)
+
 /* Various stub interrupt handlers and syscall handlers */
 
 STD_ENTRY_LOCAL(_kernel_double_fault)
···
 	panic   "Unhandled interrupt %#x: PC %#lx"
 	STD_ENDPROC(bad_intr)
 
-/* Put address of pt_regs in reg and jump. */
-#define PTREGS_SYSCALL(x, reg)                          \
-	STD_ENTRY(_##x);                                \
-	{                                               \
-	 PTREGS_PTR(reg, PTREGS_OFFSET_BASE);           \
-	 j      x                                       \
-	};                                              \
-	STD_ENDPROC(_##x)
-
 /*
  * Special-case sigreturn to not write r0 to the stack on return.
  * This is technically more efficient, but it also avoids difficulties
···
 	};                                              \
 	STD_ENDPROC(_##x)
 
-PTREGS_SYSCALL(sys_execve, r3)
-PTREGS_SYSCALL(sys_sigaltstack, r2)
 PTREGS_SYSCALL_SIGRETURN(sys_rt_sigreturn, r0)
 #ifdef CONFIG_COMPAT
-PTREGS_SYSCALL(compat_sys_execve, r3)
-PTREGS_SYSCALL(compat_sys_sigaltstack, r2)
 PTREGS_SYSCALL_SIGRETURN(compat_sys_rt_sigreturn, r0)
 #endif
 
-/* Save additional callee-saves to pt_regs, put address in r4 and jump. */
+/* Save additional callee-saves to pt_regs and jump to standard function. */
 STD_ENTRY(_sys_clone)
 	push_extra_callee_saves r4
 	j       sys_clone

arch/tile/kernel/process.c

···
 static void save_arch_state(struct thread_struct *t);
 
 int copy_thread(unsigned long clone_flags, unsigned long sp,
-		unsigned long stack_size,
-		struct task_struct *p, struct pt_regs *regs)
+		unsigned long arg,
+		struct task_struct *p, struct pt_regs *unused)
 {
-	struct pt_regs *childregs;
+	struct pt_regs *childregs = task_pt_regs(p);
 	unsigned long ksp;
+	unsigned long *callee_regs;
 
 	/*
-	 * When creating a new kernel thread we pass sp as zero.
-	 * Assign it to a reasonable value now that we have the stack.
+	 * Set up the stack and stack pointer appropriately for the
+	 * new child to find itself woken up in __switch_to().
+	 * The callee-saved registers must be on the stack to be read;
+	 * the new task will then jump to assembly support to handle
+	 * calling schedule_tail(), etc., and (for userspace tasks)
+	 * returning to the context set up in the pt_regs.
 	 */
-	if (sp == 0 && regs->ex1 == PL_ICS_EX1(KERNEL_PL, 0))
-		sp = KSTK_TOP(p);
+	ksp = (unsigned long) childregs;
+	ksp -= C_ABI_SAVE_AREA_SIZE;   /* interrupt-entry save area */
+	((long *)ksp)[0] = ((long *)ksp)[1] = 0;
+	ksp -= CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long);
+	callee_regs = (unsigned long *)ksp;
+	ksp -= C_ABI_SAVE_AREA_SIZE;   /* __switch_to() save area */
+	((long *)ksp)[0] = ((long *)ksp)[1] = 0;
+	p->thread.ksp = ksp;
+
+	/* Record the pid of the task that created this one. */
+	p->thread.creator_pid = current->pid;
+
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		/* kernel thread */
+		memset(childregs, 0, sizeof(struct pt_regs));
+		memset(&callee_regs[2], 0,
+		       (CALLEE_SAVED_REGS_COUNT - 2) * sizeof(unsigned long));
+		callee_regs[0] = sp;   /* r30 = function */
+		callee_regs[1] = arg;  /* r31 = arg */
+		childregs->ex1 = PL_ICS_EX1(KERNEL_PL, 0);
+		p->thread.pc = (unsigned long) ret_from_kernel_thread;
+		return 0;
+	}
+
+	/*
+	 * Start new thread in ret_from_fork so it schedules properly
+	 * and then return from interrupt like the parent.
+	 */
+	p->thread.pc = (unsigned long) ret_from_fork;
 
 	/*
 	 * Do not clone step state from the parent; each thread
···
 	task_thread_info(p)->step_state = NULL;
 
 	/*
-	 * Start new thread in ret_from_fork so it schedules properly
-	 * and then return from interrupt like the parent.
-	 */
-	p->thread.pc = (unsigned long) ret_from_fork;
-
-	/* Save user stack top pointer so we can ID the stack vm area later. */
-	p->thread.usp0 = sp;
-
-	/* Record the pid of the process that created this one. */
-	p->thread.creator_pid = current->pid;
-
-	/*
 	 * Copy the registers onto the kernel stack so the
 	 * return-from-interrupt code will reload it into registers.
 	 */
-	childregs = task_pt_regs(p);
-	*childregs = *regs;
+	*childregs = *current_pt_regs();
 	childregs->regs[0] = 0;         /* return value is zero */
-	childregs->sp = sp;  /* override with new user stack pointer */
+	if (sp)
+		childregs->sp = sp;  /* override with new user stack pointer */
+	memcpy(callee_regs, &childregs->regs[CALLEE_SAVED_FIRST_REG],
+	       CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long));
+
+	/* Save user stack top pointer so we can ID the stack vm area later. */
+	p->thread.usp0 = childregs->sp;
 
 	/*
 	 * If CLONE_SETTLS is set, set "tp" in the new task to "r4",
 	 * which is passed in as arg #5 to sys_clone().
 	 */
 	if (clone_flags & CLONE_SETTLS)
-		childregs->tp = regs->regs[4];
+		childregs->tp = childregs->regs[4];
 
-	/*
-	 * Copy the callee-saved registers from the passed pt_regs struct
-	 * into the context-switch callee-saved registers area.
-	 * This way when we start the interrupt-return sequence, the
-	 * callee-save registers will be correctly in registers, which
-	 * is how we assume the compiler leaves them as we start doing
-	 * the normal return-from-interrupt path after calling C code.
-	 * Zero out the C ABI save area to mark the top of the stack.
-	 */
-	ksp = (unsigned long) childregs;
-	ksp -= C_ABI_SAVE_AREA_SIZE;   /* interrupt-entry save area */
-	((long *)ksp)[0] = ((long *)ksp)[1] = 0;
-	ksp -= CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long);
-	memcpy((void *)ksp, &regs->regs[CALLEE_SAVED_FIRST_REG],
-	       CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long));
-	ksp -= C_ABI_SAVE_AREA_SIZE;   /* __switch_to() save area */
-	((long *)ksp)[0] = ((long *)ksp)[1] = 0;
-	p->thread.ksp = ksp;
 
 #if CHIP_HAS_TILE_DMA()
 	/*
···
 }
 
 /* Note there is an implicit fifth argument if (clone_flags & CLONE_SETTLS). */
-SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
-		void __user *, parent_tidptr, void __user *, child_tidptr,
-		struct pt_regs *, regs)
+SYSCALL_DEFINE4(clone, unsigned long, clone_flags, unsigned long, newsp,
+		void __user *, parent_tidptr, void __user *, child_tidptr)
 {
-	if (!newsp)
-		newsp = regs->sp;
-	return do_fork(clone_flags, newsp, regs, 0,
+	return do_fork(clone_flags, newsp, current_pt_regs(), 0,
 		       parent_tidptr, child_tidptr);
 }
-
-/*
- * sys_execve() executes a new program.
- */
-SYSCALL_DEFINE4(execve, const char __user *, path,
-		const char __user *const __user *, argv,
-		const char __user *const __user *, envp,
-		struct pt_regs *, regs)
-{
-	long error;
-	struct filename *filename;
-
-	filename = getname(path);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-	error = do_execve(filename->name, argv, envp, regs);
-	putname(filename);
-	if (error == 0)
-		single_step_execve();
-out:
-	return error;
-}
-
-#ifdef CONFIG_COMPAT
-long compat_sys_execve(const char __user *path,
-		       compat_uptr_t __user *argv,
-		       compat_uptr_t __user *envp,
-		       struct pt_regs *regs)
-{
-	long error;
-	struct filename *filename;
-
-	filename = getname(path);
-	error = PTR_ERR(filename);
-	if (IS_ERR(filename))
-		goto out;
-	error = compat_do_execve(filename->name, argv, envp, regs);
-	putname(filename);
-	if (error == 0)
-		single_step_execve();
-out:
-	return error;
-}
-#endif
 
 unsigned long get_wchan(struct task_struct *p)
 {
···
 
 	return 0;
 }
-
-/*
- * We pass in lr as zero (cleared in kernel_thread) and the caller
- * part of the backtrace ABI on the stack also zeroed (in copy_thread)
- * so that backtraces will stop with this function.
- * Note that we don't use r0, since copy_thread() clears it.
- */
-static void start_kernel_thread(int dummy, int (*fn)(int), int arg)
-{
-	do_exit(fn(arg));
-}
-
-/*
- * Create a kernel thread
- */
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-	struct pt_regs regs;
-
-	memset(&regs, 0, sizeof(regs));
-	regs.ex1 = PL_ICS_EX1(KERNEL_PL, 0);  /* run at kernel PL, no ICS */
-	regs.pc = (long) start_kernel_thread;
-	regs.flags = PT_FLAGS_CALLER_SAVES;   /* need to restore r1 and r2 */
-	regs.regs[1] = (long) fn;             /* function pointer */
-	regs.regs[2] = (long) arg;            /* parameter register */
-
-	/* Ok, create the new process.. */
-	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs,
-		       0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
 
 /* Flush thread state. */
 void flush_thread(void)

arch/tile/kernel/signal.c

···
 
 #define DEBUG_SIG 0
 
-SYSCALL_DEFINE3(sigaltstack, const stack_t __user *, uss,
-		stack_t __user *, uoss, struct pt_regs *, regs)
+SYSCALL_DEFINE2(sigaltstack, const stack_t __user *, uss,
+		stack_t __user *, uoss)
 {
-	return do_sigaltstack(uss, uoss, regs->sp);
+	return do_sigaltstack(uss, uoss, current_pt_regs()->sp);
 }
 
 
···
 }
 
 /* The assembly shim for this function arranges to ignore the return value. */
-SYSCALL_DEFINE1(rt_sigreturn, struct pt_regs *, regs)
+SYSCALL_DEFINE0(rt_sigreturn)
 {
+	struct pt_regs *regs = current_pt_regs();
 	struct rt_sigframe __user *frame =
 		(struct rt_sigframe __user *)(regs->sp);
 	sigset_t set;

arch/tile/kernel/sys.c

···
 #define sys_readahead sys32_readahead
 #endif
 
-/* Call the trampolines to manage pt_regs where necessary. */
-#define sys_execve _sys_execve
-#define sys_sigaltstack _sys_sigaltstack
+/* Call the assembly trampolines where necessary. */
+#undef sys_rt_sigreturn
 #define sys_rt_sigreturn _sys_rt_sigreturn
+#undef sys_clone
 #define sys_clone _sys_clone
-#ifndef __tilegx__
-#define sys_cmpxchg_badaddr _sys_cmpxchg_badaddr
-#endif
 
 /*
  * Note that we can't include <linux/unistd.h> here since the header

arch/tile/mm/fault.c

···
  * Synthesize the fault a PL0 process would get by doing a word-load of
  * an unaligned address or a high kernel address.
  */
-SYSCALL_DEFINE2(cmpxchg_badaddr, unsigned long, address,
-		struct pt_regs *, regs)
+SYSCALL_DEFINE1(cmpxchg_badaddr, unsigned long, address)
 {
+	struct pt_regs *regs = current_pt_regs();
+
 	if (address >= PAGE_OFFSET)
 		force_sig_info_fault("atomic segfault", SIGSEGV, SEGV_MAPERR,
 				     address, INT_DTLB_MISS, current, regs);

include/linux/compat.h

···
 
 int compat_do_execve(const char *filename, const compat_uptr_t __user *argv,
 		     const compat_uptr_t __user *envp, struct pt_regs *regs);
-#ifdef __ARCH_WANT_SYS_EXECVE
 asmlinkage long compat_sys_execve(const char __user *filename, const compat_uptr_t __user *argv,
 		     const compat_uptr_t __user *envp);
-#endif
 
 asmlinkage long compat_sys_select(int n, compat_ulong_t __user *inp,
 		compat_ulong_t __user *outp, compat_ulong_t __user *exp,