Merge branch 'x86/asm' into locking/core

Upcoming changes to static keys is interacting/conflicting with the following
pending TSC commits in tip:x86/asm:

4ea1636b04db x86/asm/tsc: Rename native_read_tsc() to rdtsc()
...

So merge it into the locking tree to have a smoother resolution.

Signed-off-by: Ingo Molnar <[e-mail]>

arch/um/include/shared/kern_util.h

···
 extern unsigned long alloc_stack(int order, int atomic);
 extern void free_stack(unsigned long stack, int order);
 
-extern int do_signal(void);
+struct pt_regs;
+extern void do_signal(struct pt_regs *regs);
 extern void interrupt_end(void);
 extern void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs);
 

arch/um/kernel/process.c

···
 
 void interrupt_end(void)
 {
+	struct pt_regs *regs = &current->thread.regs;
+
 	if (need_resched())
 		schedule();
 	if (test_thread_flag(TIF_SIGPENDING))
-		do_signal();
+		do_signal(regs);
 	if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
-		tracehook_notify_resume(&current->thread.regs);
+		tracehook_notify_resume(regs);
 }
 
 void exit_thread(void)

arch/um/kernel/signal.c

···
 	signal_setup_done(err, ksig, singlestep);
 }
 
-static int kern_do_signal(struct pt_regs *regs)
+void do_signal(struct pt_regs *regs)
 {
 	struct ksignal ksig;
 	int handled_sig = 0;
···
 	 */
 	if (!handled_sig)
 		restore_saved_sigmask();
-	return handled_sig;
-}
-
-int do_signal(void)
-{
-	return kern_do_signal(&current->thread.regs);
 }

arch/um/kernel/tlb.c

···
 		/* We are under mmap_sem, release it such that current can terminate */
 		up_write(&current->mm->mmap_sem);
 		force_sig(SIGKILL, current);
-		do_signal();
+		do_signal(&current->thread.regs);
 	}
 }
 

arch/um/kernel/trap.c

···
 void fatal_sigsegv(void)
 {
 	force_sigsegv(SIGSEGV, current);
-	do_signal();
+	do_signal(&current->thread.regs);
 	/*
 	 * This is to tell gcc that we're not returning - do_signal
 	 * can, in general, return, but in this case, it's not, since

arch/x86/Kconfig

···
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_SYSCALL_TRACEPOINTS
-	select HAVE_UID16			if X86_32
+	select HAVE_UID16			if X86_32 || IA32_EMULATION
 	select HAVE_UNSTABLE_SCHED_CLOCK
 	select HAVE_USER_RETURN_NOTIFIER
 	select IRQ_FORCED_THREADING
···
 	def_bool y
 	depends on X86_MCE_INTEL
 
-config VM86
-	bool "Enable VM86 support" if EXPERT
-	default y
+config X86_LEGACY_VM86
+	bool "Legacy VM86 support (obsolete)"
+	default n
 	depends on X86_32
 	---help---
-	  This option is required by programs like DOSEMU to run
-	  16-bit real mode legacy code on x86 processors. It also may
-	  be needed by software like XFree86 to initialize some video
-	  cards via BIOS. Disabling this option saves about 6K.
+	  This option allows user programs to put the CPU into V8086
+	  mode, which is an 80286-era approximation of 16-bit real mode.
+
+	  Some very old versions of X and/or vbetool require this option
+	  for user mode setting.  Similarly, DOSEMU will use it if
+	  available to accelerate real mode DOS programs.  However, any
+	  recent version of DOSEMU, X, or vbetool should be fully
+	  functional even without kernel VM86 support, as they will all
+	  fall back to (pretty well performing) software emulation.
+
+	  Anything that works on a 64-bit kernel is unlikely to need
+	  this option, as 64-bit kernels don't, and can't, support V8086
+	  mode.  This option is also unrelated to 16-bit protected mode
+	  and is not needed to run most 16-bit programs under Wine.
+
+	  Enabling this option adds considerable attack surface to the
+	  kernel and slows down system calls and exception handling.
+
+	  Unless you use very old userspace or need the last drop of
+	  performance in your real mode DOS games and can't use KVM,
+	  say N here.
+
+config VM86
+       bool
+       default X86_LEGACY_VM86
 
 config X86_16BIT
 	bool "Enable support for 16-bit segments" if EXPERT
 	default y
+	depends on MODIFY_LDT_SYSCALL
 	---help---
 	  This option is required by programs like Wine to run 16-bit
 	  protected mode legacy code on x86 processors.  Disabling
···
 
 config MATH_EMULATION
 	bool
+	depends on MODIFY_LDT_SYSCALL
 	prompt "Math emulation" if X86_32
 	---help---
 	  Linux can emulate a math coprocessor (used for floating point
···
 	  This is used to work around broken boot loaders.  This should
 	  be set to 'N' under normal conditions.
 
+config MODIFY_LDT_SYSCALL
+	bool "Enable the LDT (local descriptor table)" if EXPERT
+	default y
+	---help---
+	  Linux can allow user programs to install a per-process x86
+	  Local Descriptor Table (LDT) using the modify_ldt(2) system
+	  call.  This is required to run 16-bit or segmented code such as
+	  DOSEMU or some Wine programs.  It is also used by some very old
+	  threading libraries.
+
+	  Enabling this feature adds a small amount of overhead to
+	  context switches and increases the low-level kernel attack
+	  surface.  Disabling it removes the modify_ldt(2) system call.
+
+	  Saying 'N' here may make sense for embedded or server kernels.
+
 source "kernel/livepatch/Kconfig"
 
 endmenu
···
 	depends on X86_64
 	select BINFMT_ELF
 	select COMPAT_BINFMT_ELF
-	select HAVE_UID16
+	select ARCH_WANT_OLD_COMPAT_IPC
 	---help---
 	  Include code to run legacy 32-bit programs under a
 	  64-bit kernel. You should likely turn this on, unless you're
···
 
 config X86_X32
 	bool "x32 ABI for 64-bit mode"
-	depends on X86_64 && IA32_EMULATION
+	depends on X86_64
 	---help---
 	  Include code to run binaries for the x32 native 32-bit ABI
 	  for 64-bit processors.  An x32 process gets access to the
···
 config COMPAT
 	def_bool y
 	depends on IA32_EMULATION || X86_X32
-	select ARCH_WANT_OLD_COMPAT_IPC
 
 if COMPAT
 config COMPAT_FOR_U64_ALIGNMENT

arch/x86/Makefile

···
         LDFLAGS_vmlinux := --emit-relocs
 endif
 
+#
+# Prevent GCC from generating any FP code by mistake.
+#
+# This must happen before we try the -mpreferred-stack-boundary, see:
+#
+#    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
+#
+KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
+KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
+
 ifeq ($(CONFIG_X86_32),y)
         BITS := 32
         UTS_MACHINE := i386
···
 KBUILD_CFLAGS += -Wno-sign-compare
 #
 KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
-# prevent gcc from generating any FP code by mistake
-KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
-KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
 
 KBUILD_CFLAGS += $(mflags-y)
 KBUILD_AFLAGS += $(mflags-y)

arch/x86/boot/compressed/aslr.c

···
 
 	if (has_cpuflag(X86_FEATURE_TSC)) {
 		debug_putstr(" RDTSC");
-		rdtscll(raw);
+		raw = rdtsc();
 
 		random ^= raw;
 		use_i8254 = false;

arch/x86/entry/Makefile

···
 # Makefile for the x86 low level entry code
 #
 obj-y				:= entry_$(BITS).o thunk_$(BITS).o syscall_$(BITS).o
+obj-y				+= common.o
 
 obj-y				+= vdso/
 obj-y				+= vsyscall/

arch/x86/entry/calling.h

···
 	movq %rbp, 4*8+\offset(%rsp)
 	movq %rbx, 5*8+\offset(%rsp)
 	.endm
-	.macro SAVE_EXTRA_REGS_RBP offset=0
-	movq %rbp, 4*8+\offset(%rsp)
-	.endm
 
 	.macro RESTORE_EXTRA_REGS offset=0
 	movq 0*8+\offset(%rsp), %r15
···
 	.endm
 	.macro RESTORE_C_REGS_EXCEPT_RCX_R11
 	RESTORE_C_REGS_HELPER 1,0,0,1,1
-	.endm
-	.macro RESTORE_RSI_RDI
-	RESTORE_C_REGS_HELPER 0,0,0,0,0
-	.endm
-	.macro RESTORE_RSI_RDI_RDX
-	RESTORE_C_REGS_HELPER 0,0,0,0,1
 	.endm
 
 	.macro REMOVE_PT_GPREGS_FROM_STACK addskip=0

arch/x86/entry/common.c

···
+/*
+ * common.c - C code for kernel entry and exit
+ * Copyright (c) 2015 Andrew Lutomirski
+ * GPL v2
+ *
+ * Based on asm and ptrace code by many authors.  The code here originated
+ * in ptrace.c and signal.c.
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/tracehook.h>
+#include <linux/audit.h>
+#include <linux/seccomp.h>
+#include <linux/signal.h>
+#include <linux/export.h>
+#include <linux/context_tracking.h>
+#include <linux/user-return-notifier.h>
+#include <linux/uprobes.h>
+
+#include <asm/desc.h>
+#include <asm/traps.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/syscalls.h>
+
+#ifdef CONFIG_CONTEXT_TRACKING
+/* Called on entry from user mode with IRQs off. */
+__visible void enter_from_user_mode(void)
+{
+	CT_WARN_ON(ct_state() != CONTEXT_USER);
+	user_exit();
+}
+#endif
+
+static void do_audit_syscall_entry(struct pt_regs *regs, u32 arch)
+{
+#ifdef CONFIG_X86_64
+	if (arch == AUDIT_ARCH_X86_64) {
+		audit_syscall_entry(regs->orig_ax, regs->di,
+				    regs->si, regs->dx, regs->r10);
+	} else
+#endif
+	{
+		audit_syscall_entry(regs->orig_ax, regs->bx,
+				    regs->cx, regs->dx, regs->si);
+	}
+}
+
+/*
+ * We can return 0 to resume the syscall or anything else to go to phase
+ * 2.  If we resume the syscall, we need to put something appropriate in
+ * regs->orig_ax.
+ *
+ * NB: We don't have full pt_regs here, but regs->orig_ax and regs->ax
+ * are fully functional.
+ *
+ * For phase 2's benefit, our return value is:
+ * 0:			resume the syscall
+ * 1:			go to phase 2; no seccomp phase 2 needed
+ * anything else:	go to phase 2; pass return value to seccomp
+ */
+unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)
+{
+	unsigned long ret = 0;
+	u32 work;
+
+	BUG_ON(regs != task_pt_regs(current));
+
+	work = ACCESS_ONCE(current_thread_info()->flags) &
+		_TIF_WORK_SYSCALL_ENTRY;
+
+#ifdef CONFIG_CONTEXT_TRACKING
+	/*
+	 * If TIF_NOHZ is set, we are required to call user_exit() before
+	 * doing anything that could touch RCU.
+	 */
+	if (work & _TIF_NOHZ) {
+		enter_from_user_mode();
+		work &= ~_TIF_NOHZ;
+	}
+#endif
+
+#ifdef CONFIG_SECCOMP
+	/*
+	 * Do seccomp first -- it should minimize exposure of other
+	 * code, and keeping seccomp fast is probably more valuable
+	 * than the rest of this.
+	 */
+	if (work & _TIF_SECCOMP) {
+		struct seccomp_data sd;
+
+		sd.arch = arch;
+		sd.nr = regs->orig_ax;
+		sd.instruction_pointer = regs->ip;
+#ifdef CONFIG_X86_64
+		if (arch == AUDIT_ARCH_X86_64) {
+			sd.args[0] = regs->di;
+			sd.args[1] = regs->si;
+			sd.args[2] = regs->dx;
+			sd.args[3] = regs->r10;
+			sd.args[4] = regs->r8;
+			sd.args[5] = regs->r9;
+		} else
+#endif
+		{
+			sd.args[0] = regs->bx;
+			sd.args[1] = regs->cx;
+			sd.args[2] = regs->dx;
+			sd.args[3] = regs->si;
+			sd.args[4] = regs->di;
+			sd.args[5] = regs->bp;
+		}
+
+		BUILD_BUG_ON(SECCOMP_PHASE1_OK != 0);
+		BUILD_BUG_ON(SECCOMP_PHASE1_SKIP != 1);
+
+		ret = seccomp_phase1(&sd);
+		if (ret == SECCOMP_PHASE1_SKIP) {
+			regs->orig_ax = -1;
+			ret = 0;
+		} else if (ret != SECCOMP_PHASE1_OK) {
+			return ret;  /* Go directly to phase 2 */
+		}
+
+		work &= ~_TIF_SECCOMP;
+	}
+#endif
+
+	/* Do our best to finish without phase 2. */
+	if (work == 0)
+		return ret;  /* seccomp and/or nohz only (ret == 0 here) */
+
+#ifdef CONFIG_AUDITSYSCALL
+	if (work == _TIF_SYSCALL_AUDIT) {
+		/*
+		 * If there is no more work to be done except auditing,
+		 * then audit in phase 1.  Phase 2 always audits, so, if
+		 * we audit here, then we can't go on to phase 2.
+		 */
+		do_audit_syscall_entry(regs, arch);
+		return 0;
+	}
+#endif
+
+	return 1;  /* Something is enabled that we can't handle in phase 1 */
+}
+
+/* Returns the syscall nr to run (which should match regs->orig_ax). */
+long syscall_trace_enter_phase2(struct pt_regs *regs, u32 arch,
+				unsigned long phase1_result)
+{
+	long ret = 0;
+	u32 work = ACCESS_ONCE(current_thread_info()->flags) &
+		_TIF_WORK_SYSCALL_ENTRY;
+
+	BUG_ON(regs != task_pt_regs(current));
+
+	/*
+	 * If we stepped into a sysenter/syscall insn, it trapped in
+	 * kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP.
+	 * If user-mode had set TF itself, then it's still clear from
+	 * do_debug() and we need to set it again to restore the user
+	 * state.  If we entered on the slow path, TF was already set.
+	 */
+	if (work & _TIF_SINGLESTEP)
+		regs->flags |= X86_EFLAGS_TF;
+
+#ifdef CONFIG_SECCOMP
+	/*
+	 * Call seccomp_phase2 before running the other hooks so that
+	 * they can see any changes made by a seccomp tracer.
+	 */
+	if (phase1_result > 1 && seccomp_phase2(phase1_result)) {
+		/* seccomp failures shouldn't expose any additional code. */
+		return -1;
+	}
+#endif
+
+	if (unlikely(work & _TIF_SYSCALL_EMU))
+		ret = -1L;
+
+	if ((ret || test_thread_flag(TIF_SYSCALL_TRACE)) &&
+	    tracehook_report_syscall_entry(regs))
+		ret = -1L;
+
+	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
+		trace_sys_enter(regs, regs->orig_ax);
+
+	do_audit_syscall_entry(regs, arch);
+
+	return ret ?: regs->orig_ax;
+}
+
+long syscall_trace_enter(struct pt_regs *regs)
+{
+	u32 arch = is_ia32_task() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
+	unsigned long phase1_result = syscall_trace_enter_phase1(regs, arch);
+
+	if (phase1_result == 0)
+		return regs->orig_ax;
+	else
+		return syscall_trace_enter_phase2(regs, arch, phase1_result);
+}
+
+/* Deprecated. */
+void syscall_trace_leave(struct pt_regs *regs)
+{
+	bool step;
+
+	/*
+	 * We may come here right after calling schedule_user()
+	 * or do_notify_resume(), in which case we can be in RCU
+	 * user mode.
+	 */
+	user_exit();
+
+	audit_syscall_exit(regs);
+
+	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
+		trace_sys_exit(regs, regs->ax);
+
+	/*
+	 * If TIF_SYSCALL_EMU is set, we only get here because of
+	 * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
+	 * We already reported this syscall instruction in
+	 * syscall_trace_enter().
+	 */
+	step = unlikely(test_thread_flag(TIF_SINGLESTEP)) &&
+			!test_thread_flag(TIF_SYSCALL_EMU);
+	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall_exit(regs, step);
+
+	user_enter();
+}
+
+static struct thread_info *pt_regs_to_thread_info(struct pt_regs *regs)
+{
+	unsigned long top_of_stack =
+		(unsigned long)(regs + 1) + TOP_OF_KERNEL_STACK_PADDING;
+	return (struct thread_info *)(top_of_stack - THREAD_SIZE);
+}
+
+/* Called with IRQs disabled. */
+__visible void prepare_exit_to_usermode(struct pt_regs *regs)
+{
+	if (WARN_ON(!irqs_disabled()))
+		local_irq_disable();
+
+	/*
+	 * In order to return to user mode, we need to have IRQs off with
+	 * none of _TIF_SIGPENDING, _TIF_NOTIFY_RESUME, _TIF_USER_RETURN_NOTIFY,
+	 * _TIF_UPROBE, or _TIF_NEED_RESCHED set.  Several of these flags
+	 * can be set at any time on preemptable kernels if we have IRQs on,
+	 * so we need to loop.  Disabling preemption wouldn't help: doing the
+	 * work to clear some of the flags can sleep.
+	 */
+	while (true) {
+		u32 cached_flags =
+			READ_ONCE(pt_regs_to_thread_info(regs)->flags);
+
+		if (!(cached_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME |
+				      _TIF_UPROBE | _TIF_NEED_RESCHED |
+				      _TIF_USER_RETURN_NOTIFY)))
+			break;
+
+		/* We have work to do. */
+		local_irq_enable();
+
+		if (cached_flags & _TIF_NEED_RESCHED)
+			schedule();
+
+		if (cached_flags & _TIF_UPROBE)
+			uprobe_notify_resume(regs);
+
+		/* deal with pending signal delivery */
+		if (cached_flags & _TIF_SIGPENDING)
+			do_signal(regs);
+
+		if (cached_flags & _TIF_NOTIFY_RESUME) {
+			clear_thread_flag(TIF_NOTIFY_RESUME);
+			tracehook_notify_resume(regs);
+		}
+
+		if (cached_flags & _TIF_USER_RETURN_NOTIFY)
+			fire_user_return_notifiers();
+
+		/* Disable IRQs and retry */
+		local_irq_disable();
+	}
+
+	user_enter();
+}
+
+/*
+ * Called with IRQs on and fully valid regs.  Returns with IRQs off in a
+ * state such that we can immediately switch to user mode.
+ */
+__visible void syscall_return_slowpath(struct pt_regs *regs)
+{
+	struct thread_info *ti = pt_regs_to_thread_info(regs);
+	u32 cached_flags = READ_ONCE(ti->flags);
+	bool step;
+
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
+
+	if (WARN(irqs_disabled(), "syscall %ld left IRQs disabled",
+		 regs->orig_ax))
+		local_irq_enable();
+
+	/*
+	 * First do one-time work.  If these work items are enabled, we
+	 * want to run them exactly once per syscall exit with IRQs on.
+	 */
+	if (cached_flags & (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT |
+			    _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT)) {
+		audit_syscall_exit(regs);
+
+		if (cached_flags & _TIF_SYSCALL_TRACEPOINT)
+			trace_sys_exit(regs, regs->ax);
+
+		/*
+		 * If TIF_SYSCALL_EMU is set, we only get here because of
+		 * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
+		 * We already reported this syscall instruction in
+		 * syscall_trace_enter().
+		 */
+		step = unlikely(
+			(cached_flags & (_TIF_SINGLESTEP | _TIF_SYSCALL_EMU))
+			== _TIF_SINGLESTEP);
+		if (step || cached_flags & _TIF_SYSCALL_TRACE)
+			tracehook_report_syscall_exit(regs, step);
+	}
+
+#ifdef CONFIG_COMPAT
+	/*
+	 * Compat syscalls set TS_COMPAT.  Make sure we clear it before
+	 * returning to user mode.
+	 */
+	ti->status &= ~TS_COMPAT;
+#endif
+
+	local_irq_disable();
+	prepare_exit_to_usermode(regs);
+}
+
+/*
+ * Deprecated notification of userspace execution resumption
+ * - triggered by the TIF_WORK_MASK flags
+ */
+__visible void
+do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
+{
+	user_exit();
+
+	if (thread_info_flags & _TIF_UPROBE)
+		uprobe_notify_resume(regs);
+
+	/* deal with pending signal delivery */
+	if (thread_info_flags & _TIF_SIGPENDING)
+		do_signal(regs);
+
+	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
+		clear_thread_flag(TIF_NOTIFY_RESUME);
+		tracehook_notify_resume(regs);
+	}
+	if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
+		fire_user_return_notifiers();
+
+	user_enter();
+}

arch/x86/entry/entry_32.S

···
 
 work_notifysig:					# deal with pending signals and
 						# notify-resume requests
-#ifdef CONFIG_VM86
-	testl	$X86_EFLAGS_VM, PT_EFLAGS(%esp)
-	movl	%esp, %eax
-	jnz	work_notifysig_v86		# returning to kernel-space or
-						# vm86-space
-1:
-#else
-	movl	%esp, %eax
-#endif
 	TRACE_IRQS_ON
 	ENABLE_INTERRUPTS(CLBR_NONE)
-	movb	PT_CS(%esp), %bl
-	andb	$SEGMENT_RPL_MASK, %bl
-	cmpb	$USER_RPL, %bl
-	jb	resume_kernel
+	movl	%esp, %eax
 	xorl	%edx, %edx
 	call	do_notify_resume
 	jmp	resume_userspace
-
-#ifdef CONFIG_VM86
-	ALIGN
-work_notifysig_v86:
-	pushl	%ecx				# save ti_flags for do_notify_resume
-	call	save_v86_state			# %eax contains pt_regs pointer
-	popl	%ecx
-	movl	%eax, %esp
-	jmp	1b
-#endif
 END(work_pending)
 
 	# perform syscall exit tracing

arch/x86/entry/entry_64.S

···
 #include <asm/paravirt.h>
 #include <asm/percpu.h>
 #include <asm/asm.h>
-#include <asm/context_tracking.h>
 #include <asm/smap.h>
 #include <asm/pgtable_types.h>
 #include <linux/err.h>
···
 	 */
 	USERGS_SYSRET64
 
+GLOBAL(int_ret_from_sys_call_irqs_off)
+	TRACE_IRQS_ON
+	ENABLE_INTERRUPTS(CLBR_NONE)
+	jmp int_ret_from_sys_call
+
 	/* Do syscall entry tracing */
 tracesys:
 	movq	%rsp, %rdi
···
  * Has correct iret frame.
  */
 GLOBAL(int_ret_from_sys_call)
-	DISABLE_INTERRUPTS(CLBR_NONE)
-int_ret_from_sys_call_irqs_off: /* jumps come here from the irqs-off SYSRET path */
-	TRACE_IRQS_OFF
-	movl	$_TIF_ALLWORK_MASK, %edi
-	/* edi:	mask to check */
-GLOBAL(int_with_check)
-	LOCKDEP_SYS_EXIT_IRQ
-	GET_THREAD_INFO(%rcx)
-	movl	TI_flags(%rcx), %edx
-	andl	%edi, %edx
-	jnz	int_careful
-	andl	$~TS_COMPAT, TI_status(%rcx)
-	jmp	syscall_return
-
-	/*
-	 * Either reschedule or signal or syscall exit tracking needed.
-	 * First do a reschedule test.
-	 * edx:	work, edi: workmask
-	 */
-int_careful:
-	bt	$TIF_NEED_RESCHED, %edx
-	jnc	int_very_careful
-	TRACE_IRQS_ON
-	ENABLE_INTERRUPTS(CLBR_NONE)
-	pushq	%rdi
-	SCHEDULE_USER
-	popq	%rdi
-	DISABLE_INTERRUPTS(CLBR_NONE)
-	TRACE_IRQS_OFF
-	jmp	int_with_check
-
-	/* handle signals and tracing -- both require a full pt_regs */
-int_very_careful:
-	TRACE_IRQS_ON
-	ENABLE_INTERRUPTS(CLBR_NONE)
 	SAVE_EXTRA_REGS
-	/* Check for syscall exit trace */
-	testl	$_TIF_WORK_SYSCALL_EXIT, %edx
-	jz	int_signal
-	pushq	%rdi
-	leaq	8(%rsp), %rdi			/* &ptregs -> arg1 */
-	call	syscall_trace_leave
-	popq	%rdi
-	andl	$~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU), %edi
-	jmp	int_restore_rest
-
-int_signal:
-	testl	$_TIF_DO_NOTIFY_MASK, %edx
-	jz	1f
-	movq	%rsp, %rdi			/* &ptregs -> arg1 */
-	xorl	%esi, %esi			/* oldset -> arg2 */
-	call	do_notify_resume
-1:	movl	$_TIF_WORK_MASK, %edi
-int_restore_rest:
+	movq	%rsp, %rdi
+	call	syscall_return_slowpath	/* returns with IRQs disabled */
 	RESTORE_EXTRA_REGS
-	DISABLE_INTERRUPTS(CLBR_NONE)
-	TRACE_IRQS_OFF
-	jmp	int_with_check
-
-syscall_return:
-	/* The IRETQ could re-enable interrupts: */
-	DISABLE_INTERRUPTS(CLBR_ANY)
-	TRACE_IRQS_IRETQ
+	TRACE_IRQS_IRETQ		/* we're about to change IF */
 
 	/*
 	 * Try to use SYSRET instead of IRET if we're returning to
···
 /* 0(%rsp): ~(interrupt number) */
 	.macro interrupt func
 	cld
-	/*
-	 * Since nothing in interrupt handling code touches r12...r15 members
-	 * of "struct pt_regs", and since interrupts can nest, we can save
-	 * four stack slots and simultaneously provide
-	 * an unwind-friendly stack layout by saving "truncated" pt_regs
-	 * exactly up to rbp slot, without these members.
-	 */
-	ALLOC_PT_GPREGS_ON_STACK -RBP
-	SAVE_C_REGS -RBP
-	/* this goes to 0(%rsp) for unwinder, not for saving the value: */
-	SAVE_EXTRA_REGS_RBP -RBP
+	ALLOC_PT_GPREGS_ON_STACK
+	SAVE_C_REGS
+	SAVE_EXTRA_REGS
 
-	leaq	-RBP(%rsp), %rdi		/* arg1 for \func (pointer to pt_regs) */
-
-	testb	$3, CS-RBP(%rsp)
+	testb	$3, CS(%rsp)
 	jz	1f
+
+	/*
+	 * IRQ from user mode.  Switch to kernel gsbase and inform context
+	 * tracking that we're in kernel mode.
+	 */
 	SWAPGS
+#ifdef CONFIG_CONTEXT_TRACKING
+	call enter_from_user_mode
+#endif
+
 1:
 	/*
 	 * Save previous stack pointer, optionally switch to interrupt stack.
···
 	 * a little cheaper to use a separate counter in the PDA (short of
 	 * moving irq_enter into assembly, which would be too much work)
 	 */
-	movq	%rsp, %rsi
+	movq	%rsp, %rdi
 	incl	PER_CPU_VAR(irq_count)
 	cmovzq	PER_CPU_VAR(irq_stack_ptr), %rsp
-	pushq	%rsi
+	pushq	%rdi
 	/* We entered an interrupt context - irqs are off: */
 	TRACE_IRQS_OFF
 
-	call	\func
+	call	\func	/* rdi points to pt_regs */
 	.endm
 
 	/*
···
 	decl	PER_CPU_VAR(irq_count)
 
 	/* Restore saved previous stack */
-	popq	%rsi
-	/* return code expects complete pt_regs - adjust rsp accordingly: */
-	leaq	-RBP(%rsi), %rsp
+	popq	%rsp
 
 	testb	$3, CS(%rsp)
 	jz	retint_kernel
+
 	/* Interrupt came from user space */
-retint_user:
-	GET_THREAD_INFO(%rcx)
-
-	/* %rcx: thread info. Interrupts are off. */
-retint_with_reschedule:
-	movl	$_TIF_WORK_MASK, %edi
-retint_check:
 	LOCKDEP_SYS_EXIT_IRQ
-	movl	TI_flags(%rcx), %edx
-	andl	%edi, %edx
-	jnz	retint_careful
-
-retint_swapgs:					/* return to user-space */
-	/*
-	 * The iretq could re-enable interrupts:
-	 */
-	DISABLE_INTERRUPTS(CLBR_ANY)
+GLOBAL(retint_user)
+	mov	%rsp,%rdi
+	call	prepare_exit_to_usermode
 	TRACE_IRQS_IRETQ
-
 	SWAPGS
-	jmp	restore_c_regs_and_iret
+	jmp	restore_regs_and_iret
 
 /* Returning to kernel space */
 retint_kernel:
···
  * At this label, code paths which return to kernel and to user,
  * which come from interrupts/exception and from syscalls, merge.
  */
+restore_regs_and_iret:
+	RESTORE_EXTRA_REGS
 restore_c_regs_and_iret:
 	RESTORE_C_REGS
 	REMOVE_PT_GPREGS_FROM_STACK 8
···
 	popq	%rax
 	jmp	native_irq_return_iret
 #endif
-
-	/* edi: workmask, edx: work */
-retint_careful:
-	bt	$TIF_NEED_RESCHED, %edx
-	jnc	retint_signal
-	TRACE_IRQS_ON
-	ENABLE_INTERRUPTS(CLBR_NONE)
-	pushq	%rdi
-	SCHEDULE_USER
-	popq	%rdi
-	GET_THREAD_INFO(%rcx)
-	DISABLE_INTERRUPTS(CLBR_NONE)
-	TRACE_IRQS_OFF
-	jmp	retint_check
-
-retint_signal:
-	testl	$_TIF_DO_NOTIFY_MASK, %edx
-	jz	retint_swapgs
-	TRACE_IRQS_ON
-	ENABLE_INTERRUPTS(CLBR_NONE)
-	SAVE_EXTRA_REGS
-	movq	$-1, ORIG_RAX(%rsp)
-	xorl	%esi, %esi			/* oldset */
-	movq	%rsp, %rdi			/* &pt_regs */
-	call	do_notify_resume
-	RESTORE_EXTRA_REGS
-	DISABLE_INTERRUPTS(CLBR_NONE)
-	TRACE_IRQS_OFF
-	GET_THREAD_INFO(%rcx)
-	jmp	retint_with_reschedule
-
 END(common_interrupt)
 
 /*
···
 	SAVE_EXTRA_REGS 8
 	xorl	%ebx, %ebx
 	testb	$3, CS+8(%rsp)
-	jz	error_kernelspace
+	jz	.Lerror_kernelspace
 
-	/* We entered from user mode */
+.Lerror_entry_from_usermode_swapgs:
+	/*
+	 * We entered from user mode or we're pretending to have entered
+	 * from user mode due to an IRET fault.
+	 */
 	SWAPGS
 
-error_entry_done:
+.Lerror_entry_from_usermode_after_swapgs:
+#ifdef CONFIG_CONTEXT_TRACKING
+	call enter_from_user_mode
+#endif
+
+.Lerror_entry_done:
+
 	TRACE_IRQS_OFF
 	ret
 
···
 	 * truncated RIP for IRET exceptions returning to compat mode. Check
 	 * for these here too.
 	 */
-error_kernelspace:
+.Lerror_kernelspace:
 	incl	%ebx
 	leaq	native_irq_return_iret(%rip), %rcx
 	cmpq	%rcx, RIP+8(%rsp)
-	je	error_bad_iret
+	je	.Lerror_bad_iret
 	movl	%ecx, %eax			/* zero extend */
 	cmpq	%rax, RIP+8(%rsp)
-	je	bstep_iret
+	je	.Lbstep_iret
 	cmpq	$gs_change, RIP+8(%rsp)
-	jne	error_entry_done
+	jne	.Lerror_entry_done
 
 	/*
 	 * hack: gs_change can fail with user gsbase.  If this happens, fix up
 	 * gsbase and proceed.  We'll fix up the exception and land in
 	 * gs_change's error handler with kernel gsbase.
 	 */
-	SWAPGS
-	jmp	error_entry_done
+	jmp	.Lerror_entry_from_usermode_swapgs
 
-bstep_iret:
+.Lbstep_iret:
 	/* Fix truncated RIP */
 	movq	%rcx, RIP+8(%rsp)
 	/* fall through */
 
-error_bad_iret:
+.Lerror_bad_iret:
 	/*
 	 * We came from an IRET to user mode, so we have user gsbase.
 	 * Switch to kernel gsbase:
···
 	call	fixup_bad_iret
 	mov	%rax, %rsp
 	decl	%ebx
-	jmp	error_entry_done
+	jmp	.Lerror_entry_from_usermode_after_swapgs
 END(error_entry)
 
 
···
  */
 ENTRY(error_exit)
 	movl	%ebx, %eax
-	RESTORE_EXTRA_REGS
 	DISABLE_INTERRUPTS(CLBR_NONE)
 	TRACE_IRQS_OFF
 	testl	%eax, %eax

arch/x86/entry/entry_64_compat.S

···
 #define __AUDIT_ARCH_LE		0x40000000
 
 #ifndef CONFIG_AUDITSYSCALL
-# define sysexit_audit		ia32_ret_from_sys_call
-# define sysretl_audit		ia32_ret_from_sys_call
+# define sysexit_audit		ia32_ret_from_sys_call_irqs_off
+# define sysretl_audit		ia32_ret_from_sys_call_irqs_off
 #endif
 
 	.section .entry.text, "ax"
···
 	 */
 	andl	$~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
 	movl	RIP(%rsp), %ecx		/* User %eip */
-	RESTORE_RSI_RDI
+	movl	RSI(%rsp), %esi
+	movl	RDI(%rsp), %edi
 	xorl	%edx, %edx		/* Do not leak kernel information */
 	xorq	%r8, %r8
 	xorq	%r9, %r9
···
 	.endm
 
 	.macro auditsys_exit exit
-	testl	$(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
-	jnz	ia32_ret_from_sys_call
 	TRACE_IRQS_ON
 	ENABLE_INTERRUPTS(CLBR_NONE)
+	testl	$(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+	jnz	ia32_ret_from_sys_call
 	movl	%eax, %esi		/* second arg, syscall return value */
 	cmpl	$-MAX_ERRNO, %eax	/* is it an error ? */
 	jbe	1f
···
 	movq	%rax, R10(%rsp)
 	movq	%rax, R9(%rsp)
 	movq	%rax, R8(%rsp)
-	jmp	int_with_check
+	jmp	int_ret_from_sys_call_irqs_off
 	.endm
 
 sysenter_auditsys:
···
 
 sysretl_from_sys_call:
 	andl	$~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
-	RESTORE_RSI_RDI_RDX
+	movl	RDX(%rsp), %edx
+	movl	RSI(%rsp), %esi
+	movl	RDI(%rsp), %edi
 	movl	RIP(%rsp), %ecx
 	movl	EFLAGS(%rsp), %r11d
 	xorq	%r10, %r10
···
 END(entry_SYSCALL_compat)
 
 ia32_badarg:
-	ASM_CLAC
-	movq	$-EFAULT, RAX(%rsp)
+	/*
+	 * So far, we've entered kernel mode, set AC, turned on IRQs, and
+	 * saved C regs except r8-r11.  We haven't done any of the other
+	 * standard entry work, though.  We want to bail, but we shouldn't
+	 * treat this as a syscall entry since we don't even know what the
+	 * args are.  Instead, treat this as a non-syscall entry, finish
+	 * the entry work, and immediately exit after setting AX = -EFAULT.
+	 *
+	 * We're really just being polite here.  Killing the task outright
+	 * would be a reasonable action, too.  Given that the only valid
+	 * way to have gotten here is through the vDSO, and we already know
+	 * that the stack pointer is bad, the task isn't going to survive
+	 * for long no matter what we do.
+	 */
+
+	ASM_CLAC			/* undo STAC */
+	movq	$-EFAULT, RAX(%rsp)	/* return -EFAULT if possible */
+
+	/* Fill in the rest of pt_regs */
+	xorl	%eax, %eax
+	movq	%rax, R11(%rsp)
+	movq	%rax, R10(%rsp)
+	movq	%rax, R9(%rsp)
+	movq	%rax, R8(%rsp)
+	SAVE_EXTRA_REGS
+
+	/* Turn IRQs back off. */
+	DISABLE_INTERRUPTS(CLBR_NONE)
+	TRACE_IRQS_OFF
+
+	/* Now finish entering normal kernel mode. */
+#ifdef CONFIG_CONTEXT_TRACKING
+	call enter_from_user_mode
+#endif
+
+	/* And exit again. */
+	jmp retint_user
+
+ia32_ret_from_sys_call_irqs_off:
+	TRACE_IRQS_ON
+	ENABLE_INTERRUPTS(CLBR_NONE)
+
 ia32_ret_from_sys_call:
 	xorl	%eax, %eax		/* Do not leak kernel information */
 	movq	%rax, R11(%rsp)

arch/x86/entry/syscalls/syscall_32.tbl

···
 356	i386	memfd_create		sys_memfd_create
 357	i386	bpf			sys_bpf
 358	i386	execveat		sys_execveat			stub32_execveat
+359	i386	socket			sys_socket
+360	i386	socketpair		sys_socketpair
+361	i386	bind			sys_bind
+362	i386	connect			sys_connect
+363	i386	listen			sys_listen
+364	i386	accept4			sys_accept4
+365	i386	getsockopt		sys_getsockopt			compat_sys_getsockopt
+366	i386	setsockopt		sys_setsockopt			compat_sys_setsockopt
+367	i386	getsockname		sys_getsockname
+368	i386	getpeername		sys_getpeername
+369	i386	sendto			sys_sendto
+370	i386	sendmsg			sys_sendmsg			compat_sys_sendmsg
+371	i386	recvfrom		sys_recvfrom			compat_sys_recvfrom
+372	i386	recvmsg			sys_recvmsg			compat_sys_recvmsg
+373	i386	shutdown		sys_shutdown

arch/x86/entry/vdso/Makefile

···
 VDSO64-$(CONFIG_X86_64)		:= y
 VDSOX32-$(CONFIG_X86_X32_ABI)	:= y
 VDSO32-$(CONFIG_X86_32)		:= y
-VDSO32-$(CONFIG_COMPAT)		:= y
+VDSO32-$(CONFIG_IA32_EMULATION)	:= y
 
 # files to link into the vdso
 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
···
 vdso_img-$(VDSO64-y)		+= 64
 vdso_img-$(VDSOX32-y)		+= x32
 vdso_img-$(VDSO32-y)		+= 32-int80
-vdso_img-$(CONFIG_COMPAT)	+= 32-syscall
+vdso_img-$(CONFIG_IA32_EMULATION)	+= 32-syscall
 vdso_img-$(VDSO32-y)		+= 32-sysenter
 
 obj-$(VDSO32-y)			+= vdso32-setup.o
···
 # Build multiple 32-bit vDSO images to choose from at boot time.
 #
 vdso32.so-$(VDSO32-y)		+= int80
-vdso32.so-$(CONFIG_COMPAT)	+= syscall
+vdso32.so-$(CONFIG_IA32_EMULATION)	+= syscall
 vdso32.so-$(VDSO32-y)		+= sysenter
 
 vdso32-images			= $(vdso32.so-y:%=vdso32-%.so)

arch/x86/entry/vdso/vclock_gettime.c

···
 
 notrace static cycle_t vread_tsc(void)
 {
-	cycle_t ret;
-	u64 last;
-
-	/*
-	 * Empirically, a fence (of type that depends on the CPU)
-	 * before rdtsc is enough to ensure that rdtsc is ordered
-	 * with respect to loads.  The various CPU manuals are unclear
-	 * as to whether rdtsc can be reordered with later loads,
-	 * but no one has ever seen it happen.
-	 */
-	rdtsc_barrier();
-	ret = (cycle_t)__native_read_tsc();
-
-	last = gtod->cycle_last;
+	cycle_t ret = (cycle_t)rdtsc_ordered();
+	u64 last = gtod->cycle_last;
 
 	if (likely(ret >= last))
 		return ret;

arch/x86/entry/vdso/vma.c

···
 	return ret;
 }
 
-#if defined(CONFIG_X86_32) || defined(CONFIG_COMPAT)
+#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 static int load_vdso32(void)
 {
 	int ret;
···
 		return map_vdso(&vdso_image_x32, true);
 	}
 #endif
-
+#ifdef CONFIG_IA32_EMULATION
 	return load_vdso32();
+#else
+	return 0;
+#endif
 }
 #endif
 #else

arch/x86/entry/vsyscall/vsyscall_64.c

···
 
 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 {
-#ifdef CONFIG_IA32_EMULATION
+#ifdef CONFIG_COMPAT
 	if (!mm || mm->context.ia32_compat)
 		return NULL;
 #endif

arch/x86/ia32/ia32_signal.c

···
 #include <asm/sys_ia32.h>
 #include <asm/smap.h>
 
-int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
-{
-	int err = 0;
-	bool ia32 = test_thread_flag(TIF_IA32);
-
-	if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
-		return -EFAULT;
-
-	put_user_try {
-		/* If you change siginfo_t structure, please make sure that
-		   this code is fixed accordingly.
-		   It should never copy any pad contained in the structure
-		   to avoid security leaks, but must copy the generic
-		   3 ints plus the relevant union member.  */
-		put_user_ex(from->si_signo, &to->si_signo);
-		put_user_ex(from->si_errno, &to->si_errno);
-		put_user_ex((short)from->si_code, &to->si_code);
-
-		if (from->si_code < 0) {
-			put_user_ex(from->si_pid, &to->si_pid);
-			put_user_ex(from->si_uid, &to->si_uid);
-			put_user_ex(ptr_to_compat(from->si_ptr), &to->si_ptr);
-		} else {
-			/*
-			 * First 32bits of unions are always present:
-			 * si_pid === si_band === si_tid === si_addr(LS half)
-			 */
-			put_user_ex(from->_sifields._pad[0],
-					  &to->_sifields._pad[0]);
-			switch (from->si_code >> 16) {
-			case __SI_FAULT >> 16:
-				break;
-			case __SI_SYS >> 16:
-				put_user_ex(from->si_syscall, &to->si_syscall);
-				put_user_ex(from->si_arch, &to->si_arch);
-				break;
-			case __SI_CHLD >> 16:
-				if (ia32) {
-					put_user_ex(from->si_utime, &to->si_utime);
-					put_user_ex(from->si_stime, &to->si_stime);
-				} else {
-					put_user_ex(from->si_utime, &to->_sifields._sigchld_x32._utime);
-					put_user_ex(from->si_stime, &to->_sifields._sigchld_x32._stime);
-				}
-				put_user_ex(from->si_status, &to->si_status);
-				/* FALL THROUGH */
-			default:
-			case __SI_KILL >> 16:
-				put_user_ex(from->si_uid, &to->si_uid);
-				break;
-			case __SI_POLL >> 16:
-				put_user_ex(from->si_fd, &to->si_fd);
-				break;
-			case __SI_TIMER >> 16:
-				put_user_ex(from->si_overrun, &to->si_overrun);
-				put_user_ex(ptr_to_compat(from->si_ptr),
-					    &to->si_ptr);
-				break;
-				 /* This is not generated by the kernel as of now.  */
-			case __SI_RT >> 16:
-			case __SI_MESGQ >> 16:
-				put_user_ex(from->si_uid, &to->si_uid);
-				put_user_ex(from->si_int, &to->si_int);
-				break;
-			}
-		}
-	} put_user_catch(err);
-
-	return err;
-}
-
-int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
-{
-	int err = 0;
-	u32 ptr32;
-
-	if (!access_ok(VERIFY_READ, from, sizeof(compat_siginfo_t)))
-		return -EFAULT;
-
-	get_user_try {
-		get_user_ex(to->si_signo, &from->si_signo);
-		get_user_ex(to->si_errno, &from->si_errno);
-		get_user_ex(to->si_code, &from->si_code);
-
-		get_user_ex(to->si_pid, &from->si_pid);
-		get_user_ex(to->si_uid, &from->si_uid);
-		get_user_ex(ptr32, &from->si_ptr);
-		to->si_ptr = compat_ptr(ptr32);
-	} get_user_catch(err);
-
-	return err;
-}
-
 /*
  * Do a signal return; undo the signal stack.
  */

arch/x86/include/asm/barrier.h

···
 #define smp_mb__before_atomic()	barrier()
 #define smp_mb__after_atomic()	barrier()
 
-/*
- * Stop RDTSC speculation. This is needed when you need to use RDTSC
- * (or get_cycles or vread that possibly accesses the TSC) in a defined
- * code region.
- */
-static __always_inline void rdtsc_barrier(void)
-{
-	alternative_2("", "mfence", X86_FEATURE_MFENCE_RDTSC,
-			  "lfence", X86_FEATURE_LFENCE_RDTSC);
-}
-
 #endif /* _ASM_X86_BARRIER_H */

arch/x86/include/asm/context_tracking.h

···
-#ifndef _ASM_X86_CONTEXT_TRACKING_H
-#define _ASM_X86_CONTEXT_TRACKING_H
-
-#ifdef CONFIG_CONTEXT_TRACKING
-# define SCHEDULE_USER call schedule_user
-#else
-# define SCHEDULE_USER call schedule
-#endif
-
-#endif

arch/x86/include/asm/elf.h

···
 #ifdef CONFIG_X86_64
 extern unsigned int vdso64_enabled;
 #endif
-#if defined(CONFIG_X86_32) || defined(CONFIG_COMPAT)
+#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 extern unsigned int vdso32_enabled;
 #endif
 
···
 #define	COMPAT_ELF_PLAT_INIT(regs, load_addr)		\
 	elf_common_init(&current->thread, regs, __USER_DS)
 
-void start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp);
-#define compat_start_thread start_thread_ia32
+void compat_start_thread(struct pt_regs *regs, u32 new_ip, u32 new_sp);
+#define compat_start_thread compat_start_thread
 
 void set_personality_ia32(bool);
 #define COMPAT_SET_PERSONALITY(ex)			\
···
  */
 static inline int mmap_is_ia32(void)
 {
-#ifdef CONFIG_X86_32
-	return 1;
-#endif
-#ifdef CONFIG_IA32_EMULATION
-	if (test_thread_flag(TIF_ADDR32))
-		return 1;
-#endif
-	return 0;
+	return config_enabled(CONFIG_X86_32) ||
+	       (config_enabled(CONFIG_COMPAT) &&
+		test_thread_flag(TIF_ADDR32));
 }
 
 /* Do not change the values. See get_align_mask() */

arch/x86/include/asm/ia32.h

···
 	compat_sigset_t	  uc_sigmask;	/* mask last for extensibility */
 };
 
-struct ucontext_x32 {
-	unsigned int	  uc_flags;
-	unsigned int 	  uc_link;
-	compat_stack_t	  uc_stack;
-	unsigned int	  uc__pad0;     /* needed for alignment */
-	struct sigcontext uc_mcontext;  /* the 64-bit sigcontext type */
-	compat_sigset_t	  uc_sigmask;	/* mask last for extensibility */
-};
-
 /* This matches struct stat64 in glibc2.2, hence the absolutely
  * insane amounts of padding around dev_t's.
  */

arch/x86/include/asm/irq_vectors.h

···
 
 #define FPU_IRQ				  13
 
-#define	FIRST_VM86_IRQ			   3
-#define LAST_VM86_IRQ			  15
-
-#ifndef __ASSEMBLY__
-static inline int invalid_vm86_irq(int irq)
-{
-	return irq < FIRST_VM86_IRQ || irq > LAST_VM86_IRQ;
-}
-#endif
-
 /*
  * Size the maximum number of interrupts.
  *

arch/x86/include/asm/math_emu.h

···
 #define _ASM_X86_MATH_EMU_H
 
 #include <asm/ptrace.h>
-#include <asm/vm86.h>
 
 /* This structure matches the layout of the data saved to the stack
    following a device-not-present interrupt, part of it saved
···
    */
 struct math_emu_info {
 	long ___orig_eip;
-	union {
-		struct pt_regs *regs;
-		struct kernel_vm86_regs *vm86;
-	};
+	struct pt_regs *regs;
 };
 #endif /* _ASM_X86_MATH_EMU_H */

arch/x86/include/asm/mmu.h

···
  * we put the segment information here.
  */
 typedef struct {
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
 	struct ldt_struct *ldt;
+#endif
 
 #ifdef CONFIG_X86_64
 	/* True if mm supports a task running in 32 bit compatibility mode. */

arch/x86/include/asm/mmu_context.h

···
 static inline void load_mm_cr4(struct mm_struct *mm) {}
 #endif
 
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
 /*
  * ldt_structs can be allocated, used, and freed, but they are never
  * modified while live.
···
 	int size;
 };
 
+/*
+ * Used for LDT copy/destruction.
+ */
+int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
+void destroy_context(struct mm_struct *mm);
+#else	/* CONFIG_MODIFY_LDT_SYSCALL */
+static inline int init_new_context(struct task_struct *tsk,
+				   struct mm_struct *mm)
+{
+	return 0;
+}
+static inline void destroy_context(struct mm_struct *mm) {}
+#endif
+
 static inline void load_mm_ldt(struct mm_struct *mm)
 {
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
 	struct ldt_struct *ldt;
 
 	/* lockless_dereference synchronizes with smp_store_release */
···
 		set_ldt(ldt->entries, ldt->size);
 	else
 		clear_LDT();
+#else
+	clear_LDT();
+#endif
 
 	DEBUG_LOCKS_WARN_ON(preemptible());
 }
-
-/*
- * Used for LDT copy/destruction.
- */
-int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
-void destroy_context(struct mm_struct *mm);
-
 
 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 {
···
 		/* Load per-mm CR4 state */
 		load_mm_cr4(next);
 
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
 		/*
 		 * Load the LDT, if the LDT is different.
 		 *
···
 		 */
 		if (unlikely(prev->context.ldt != next->context.ldt))
 			load_mm_ldt(next);
+#endif
 	}
 #ifdef CONFIG_SMP
 	  else {

arch/x86/include/asm/msr.h

···
  * it means rax *or* rdx.
  */
 #ifdef CONFIG_X86_64
-#define DECLARE_ARGS(val, low, high)	unsigned low, high
-#define EAX_EDX_VAL(val, low, high)	((low) | ((u64)(high) << 32))
-#define EAX_EDX_ARGS(val, low, high)	"a" (low), "d" (high)
+/* Using 64-bit values saves one instruction clearing the high half of low */
+#define DECLARE_ARGS(val, low, high)	unsigned long low, high
+#define EAX_EDX_VAL(val, low, high)	((low) | (high) << 32)
 #define EAX_EDX_RET(val, low, high)	"=a" (low), "=d" (high)
 #else
 #define DECLARE_ARGS(val, low, high)	unsigned long long val
 #define EAX_EDX_VAL(val, low, high)	(val)
-#define EAX_EDX_ARGS(val, low, high)	"A" (val)
 #define EAX_EDX_RET(val, low, high)	"=A" (val)
 #endif
 
···
 	return err;
 }
 
-extern unsigned long long native_read_tsc(void);
-
 extern int rdmsr_safe_regs(u32 regs[8]);
 extern int wrmsr_safe_regs(u32 regs[8]);
 
-static __always_inline unsigned long long __native_read_tsc(void)
+/**
+ * rdtsc() - returns the current TSC without ordering constraints
+ *
+ * rdtsc() returns the result of RDTSC as a 64-bit integer.  The
+ * only ordering constraint it supplies is the ordering implied by
+ * "asm volatile": it will put the RDTSC in the place you expect.  The
+ * CPU can and will speculatively execute that RDTSC, though, so the
+ * results can be non-monotonic if compared on different CPUs.
+ */
+static __always_inline unsigned long long rdtsc(void)
 {
 	DECLARE_ARGS(val, low, high);
 
 	asm volatile("rdtsc" : EAX_EDX_RET(val, low, high));
 
 	return EAX_EDX_VAL(val, low, high);
+}
+
+/**
+ * rdtsc_ordered() - read the current TSC in program order
+ *
+ * rdtsc_ordered() returns the result of RDTSC as a 64-bit integer.
+ * It is ordered like a load to a global in-memory counter.  It should
+ * be impossible to observe non-monotonic rdtsc_unordered() behavior
+ * across multiple CPUs as long as the TSC is synced.
+ */
+static __always_inline unsigned long long rdtsc_ordered(void)
+{
+	/*
+	 * The RDTSC instruction is not ordered relative to memory
+	 * access.  The Intel SDM and the AMD APM are both vague on this
+	 * point, but empirically an RDTSC instruction can be
+	 * speculatively executed before prior loads.  An RDTSC
+	 * immediately after an appropriate barrier appears to be
+	 * ordered as a normal load, that is, it provides the same
+	 * ordering guarantees as reading from a global memory location
+	 * that some other imaginary CPU is updating continuously with a
+	 * time stamp.
+	 */
+	alternative_2("", "mfence", X86_FEATURE_MFENCE_RDTSC,
+			  "lfence", X86_FEATURE_LFENCE_RDTSC);
+	return rdtsc();
 }
 
 static inline unsigned long long native_read_pmc(int counter)
···
 	return err;
 }
 
-#define rdtscl(low)						\
-	((low) = (u32)__native_read_tsc())
-
-#define rdtscll(val)						\
-	((val) = __native_read_tsc())
-
 #define rdpmc(counter, low, high)			\
 do {							\
 	u64 _l = native_read_pmc((counter));		\
···
 } while (0)
 
 #define rdpmcl(counter, val) ((val) = native_read_pmc(counter))
-
-#define rdtscp(low, high, aux)					\
-do {                                                            \
-	unsigned long long _val = native_read_tscp(&(aux));     \
-	(low) = (u32)_val;                                      \
-	(high) = (u32)(_val >> 32);                             \
-} while (0)
-
-#define rdtscpll(val, aux) (val) = native_read_tscp(&(aux))
 
 #endif	/* !CONFIG_PARAVIRT */
 

arch/x86/include/asm/paravirt.h

···
 	return err;
 }
 
-static inline u64 paravirt_read_tsc(void)
-{
-	return PVOP_CALL0(u64, pv_cpu_ops.read_tsc);
-}
-
-#define rdtscl(low)				\
-do {						\
-	u64 _l = paravirt_read_tsc();		\
-	low = (int)_l;				\
-} while (0)
-
-#define rdtscll(val) (val = paravirt_read_tsc())
-
 static inline unsigned long long paravirt_sched_clock(void)
 {
 	return PVOP_CALL0(unsigned long long, pv_time_ops.sched_clock);
···
 } while (0)
 
 #define rdpmcl(counter, val) ((val) = paravirt_read_pmc(counter))
-
-static inline unsigned long long paravirt_rdtscp(unsigned int *aux)
-{
-	return PVOP_CALL1(u64, pv_cpu_ops.read_tscp, aux);
-}
-
-#define rdtscp(low, high, aux)				\
-do {							\
-	int __aux;					\
-	unsigned long __val = paravirt_rdtscp(&__aux);	\
-	(low) = (u32)__val;				\
-	(high) = (u32)(__val >> 32);			\
-	(aux) = __aux;					\
-} while (0)
-
-#define rdtscpll(val, aux)				\
-do {							\
-	unsigned long __aux; 				\
-	val = paravirt_rdtscp(&__aux);			\
-	(aux) = __aux;					\
-} while (0)
 
 static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries)
 {

arch/x86/include/asm/paravirt_types.h

···
 	u64 (*read_msr)(unsigned int msr, int *err);
 	int (*write_msr)(unsigned int msr, unsigned low, unsigned high);
 
-	u64 (*read_tsc)(void);
 	u64 (*read_pmc)(int counter);
-	unsigned long long (*read_tscp)(unsigned int *aux);
 
 #ifdef CONFIG_X86_32
 	/*

arch/x86/include/asm/processor.h

···
 /* Forward declaration, a strange C thing */
 struct task_struct;
 struct mm_struct;
+struct vm86;
 
-#include <asm/vm86.h>
 #include <asm/math_emu.h>
 #include <asm/segment.h>
 #include <asm/types.h>
···
 	unsigned long		cr2;
 	unsigned long		trap_nr;
 	unsigned long		error_code;
-#ifdef CONFIG_X86_32
+#ifdef CONFIG_VM86
 	/* Virtual 86 mode info */
-	struct vm86_struct __user *vm86_info;
-	unsigned long		screen_bitmap;
-	unsigned long		v86flags;
-	unsigned long		v86mask;
-	unsigned long		saved_sp0;
-	unsigned int		saved_fs;
-	unsigned int		saved_gs;
+	struct vm86		*vm86;
 #endif
 	/* IO permissions: */
 	unsigned long		*io_bitmap_ptr;
···
 
 #define INIT_THREAD  {							  \
 	.sp0			= TOP_OF_INIT_STACK,			  \
-	.vm86_info		= NULL,					  \
 	.sysenter_cs		= __KERNEL_CS,				  \
 	.io_bitmap_ptr		= NULL,					  \
 }

arch/x86/include/asm/pvclock.h

···
 static __always_inline
 u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src)
 {
-	u64 delta = __native_read_tsc() - src->tsc_timestamp;
+	u64 delta = rdtsc_ordered() - src->tsc_timestamp;
 	return pvclock_scale_delta(delta, src->tsc_to_system_mul,
 				   src->tsc_shift);
 }
···
 	u8 ret_flags;
 
 	version = src->version;
-	/* Note: emulated platforms which do not advertise SSE2 support
-	 * result in kvmclock not using the necessary RDTSC barriers.
-	 * Without barriers, it is possible that RDTSC instruction reads from
-	 * the time stamp counter outside rdtsc_barrier protected section
-	 * below, resulting in violation of monotonicity.
-	 */
-	rdtsc_barrier();
+
 	offset = pvclock_get_nsec_offset(src);
 	ret = src->system_time + offset;
 	ret_flags = src->flags;

arch/x86/include/asm/sigframe.h

···
 #include <asm/sigcontext.h>
 #include <asm/siginfo.h>
 #include <asm/ucontext.h>
+#include <linux/compat.h>
 
 #ifdef CONFIG_X86_32
 #define sigframe_ia32		sigframe
···
 };
 
 #ifdef CONFIG_X86_X32_ABI
+
+struct ucontext_x32 {
+	unsigned int	  uc_flags;
+	unsigned int 	  uc_link;
+	compat_stack_t	  uc_stack;
+	unsigned int	  uc__pad0;     /* needed for alignment */
+	struct sigcontext uc_mcontext;  /* the 64-bit sigcontext type */
+	compat_sigset_t	  uc_sigmask;	/* mask last for extensibility */
+};
 
 struct rt_sigframe_x32 {
 	u64 pretcode;

arch/x86/include/asm/signal.h

···
 #endif /* __ASSEMBLY__ */
 #include <uapi/asm/signal.h>
 #ifndef __ASSEMBLY__
+extern void do_signal(struct pt_regs *regs);
 extern void do_notify_resume(struct pt_regs *, void *, __u32);
 
 #define __ARCH_HAS_SA_RESTORER

arch/x86/include/asm/stackprotector.h

···
 	 * on during the bootup the random pool has true entropy too.
 	 */
 	get_random_bytes(&canary, sizeof(canary));
-	tsc = __native_read_tsc();
+	tsc = rdtsc();
 	canary += tsc + (tsc << 32UL);
 
 	current->stack_canary = canary;

arch/x86/include/asm/syscalls.h

···
 asmlinkage unsigned long sys_sigreturn(void);
 
 /* kernel/vm86_32.c */
+struct vm86_struct;
 asmlinkage long sys_vm86old(struct vm86_struct __user *);
 asmlinkage long sys_vm86(unsigned long, unsigned long);
 

arch/x86/include/asm/thread_info.h

···
  * Without this offset, that can result in a page fault.  (We are
  * careful that, in this case, the value we read doesn't matter.)
  *
- * In vm86 mode, the hardware frame is much longer still, but we neither
- * access the extra members from NMI context, nor do we write such a
- * frame at sp0 at all.
+ * In vm86 mode, the hardware frame is much longer still, so add 16
+ * bytes to make room for the real-mode segments.
  *
  * x86_64 has a fixed-length stack frame.
  */
 #ifdef CONFIG_X86_32
-# define TOP_OF_KERNEL_STACK_PADDING 8
+# ifdef CONFIG_VM86
+#  define TOP_OF_KERNEL_STACK_PADDING 16
+# else
+#  define TOP_OF_KERNEL_STACK_PADDING 8
+# endif
 #else
 # define TOP_OF_KERNEL_STACK_PADDING 0
 #endif

arch/x86/include/asm/traps.h

···
 asmlinkage void smp_deferred_error_interrupt(void);
 #endif
 
-extern enum ctx_state ist_enter(struct pt_regs *regs);
-extern void ist_exit(struct pt_regs *regs, enum ctx_state prev_state);
+extern void ist_enter(struct pt_regs *regs);
+extern void ist_exit(struct pt_regs *regs);
 extern void ist_begin_non_atomic(struct pt_regs *regs);
 extern void ist_end_non_atomic(void);
 

arch/x86/include/asm/tsc.h

···
 
 static inline cycles_t get_cycles(void)
 {
-	unsigned long long ret = 0;
-
 #ifndef CONFIG_X86_TSC
 	if (!cpu_has_tsc)
 		return 0;
 #endif
-	rdtscll(ret);
 
-	return ret;
-}
-
-static __always_inline cycles_t vget_cycles(void)
-{
-	/*
-	 * We only do VDSOs on TSC capable CPUs, so this shouldn't
-	 * access boot_cpu_data (which is not VDSO-safe):
-	 */
-#ifndef CONFIG_X86_TSC
-	if (!cpu_has_tsc)
-		return 0;
-#endif
-	return (cycles_t)__native_read_tsc();
+	return rdtsc();
 }
 
 extern void tsc_init(void);

arch/x86/include/asm/vm86.h

···
 #ifndef _ASM_X86_VM86_H
 #define _ASM_X86_VM86_H
 
-
 #include <asm/ptrace.h>
 #include <uapi/asm/vm86.h>
 
···
 	unsigned short gs, __gsh;
 };
 
-struct kernel_vm86_struct {
-	struct kernel_vm86_regs regs;
-/*
- * the below part remains on the kernel stack while we are in VM86 mode.
- * 'tss.esp0' then contains the address of VM86_TSS_ESP0 below, and when we
- * get forced back from VM86, the CPU and "SAVE_ALL" will restore the above
- * 'struct kernel_vm86_regs' with the then actual values.
- * Therefore, pt_regs in fact points to a complete 'kernel_vm86_struct'
- * in kernelspace, hence we need not reget the data from userspace.
- */
-#define VM86_TSS_ESP0 flags
+struct vm86 {
+	struct vm86plus_struct __user *user_vm86;
+	struct pt_regs regs32;
+	unsigned long veflags;
+	unsigned long veflags_mask;
+	unsigned long saved_sp0;
+
 	unsigned long flags;
 	unsigned long screen_bitmap;
 	unsigned long cpu_type;
 	struct revectored_struct int_revectored;
 	struct revectored_struct int21_revectored;
 	struct vm86plus_info_struct vm86plus;
-	struct pt_regs *regs32;   /* here we save the pointer to the old regs */
-/*
- * The below is not part of the structure, but the stack layout continues
- * this way. In front of 'return-eip' may be some data, depending on
- * compilation, so we don't rely on this and save the pointer to 'oldregs'
- * in 'regs32' above.
- * However, with GCC-2.7.2 and the current CFLAGS you see exactly this:
-
-	long return-eip;        from call to vm86()
-	struct pt_regs oldregs;  user space registers as saved by syscall
- */
 };
 
 #ifdef CONFIG_VM86
 
 void handle_vm86_fault(struct kernel_vm86_regs *, long);
 int handle_vm86_trap(struct kernel_vm86_regs *, long, int);
-struct pt_regs *save_v86_state(struct kernel_vm86_regs *);
+void save_v86_state(struct kernel_vm86_regs *, int);
 
 struct task_struct;
+
+#define free_vm86(t) do {				\
+	struct thread_struct *__t = (t);		\
+	if (__t->vm86 != NULL) {			\
+		kfree(__t->vm86);			\
+		__t->vm86 = NULL;			\
+	}						\
+} while (0)
+
+/*
+ * Support for VM86 programs to request interrupts for
+ * real mode hardware drivers:
+ */
+#define FIRST_VM86_IRQ		 3
+#define LAST_VM86_IRQ		15
+
+static inline int invalid_vm86_irq(int irq)
+{
+	return irq < FIRST_VM86_IRQ || irq > LAST_VM86_IRQ;
+}
+
 void release_vm86_irqs(struct task_struct *);
 
 #else
···
 {
 	return 0;
 }
+
+static inline void save_v86_state(struct kernel_vm86_regs *a, int b) { }
+
+#define free_vm86(t) do { } while(0)
 
 #endif /* CONFIG_VM86 */
 

arch/x86/kernel/Makefile

···
 CFLAGS_irq.o := -I$(src)/../include/asm/trace
 
 obj-y			:= process_$(BITS).o signal.o
+obj-$(CONFIG_COMPAT)	+= signal_compat.o
 obj-y			+= traps.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
-obj-y			+= time.o ioport.o ldt.o dumpstack.o nmi.o
+obj-y			+= time.o ioport.o dumpstack.o nmi.o
+obj-$(CONFIG_MODIFY_LDT_SYSCALL)	+= ldt.o
 obj-y			+= setup.o x86_init.o i8259.o irqinit.o jump_label.o
 obj-$(CONFIG_IRQ_WORK)  += irq_work.o
 obj-y			+= probe_roms.o

arch/x86/kernel/apb_timer.c

···
 
 	/* Verify whether apbt counter works */
 	t1 = dw_apb_clocksource_read(clocksource_apbt);
-	rdtscll(start);
+	start = rdtsc();
 
 	/*
 	 * We don't know the TSC frequency yet, but waiting for
···
 	 */
 	do {
 		rep_nop();
-		rdtscll(now);
+		now = rdtsc();
 	} while ((now - start) < 200000UL);
 
 	/* APBT is the only always on clocksource, it has to work! */
···
 	old = dw_apb_clocksource_read(clocksource_apbt);
 	old += loop;
 
-	t1 = __native_read_tsc();
+	t1 = rdtsc();
 
 	do {
 		new = dw_apb_clocksource_read(clocksource_apbt);
 	} while (new < old);
 
-	t2 = __native_read_tsc();
+	t2 = rdtsc();
 
 	shift = 5;
 	if (unlikely(loop >> shift == 0)) {

arch/x86/kernel/apic/apic.c

···
 {
 	u64 tsc;
 
-	rdtscll(tsc);
+	tsc = rdtsc();
 	wrmsrl(MSR_IA32_TSC_DEADLINE, tsc + (((u64) delta) * TSC_DIVISOR));
 	return 0;
 }
···
 	unsigned long pm = acpi_pm_read_early();
 
 	if (cpu_has_tsc)
-		rdtscll(tsc);
+		tsc = rdtsc();
 
 	switch (lapic_cal_loops++) {
 	case 0:
···
 	long long max_loops = cpu_khz ? cpu_khz : 1000000;
 
 	if (cpu_has_tsc)
-		rdtscll(tsc);
+		tsc = rdtsc();
 
 	if (disable_apic) {
 		disable_ioapic_support();
···
 		}
 		if (queued) {
 			if (cpu_has_tsc && cpu_khz) {
-				rdtscll(ntsc);
+				ntsc = rdtsc();
 				max_loops = (cpu_khz << 10) - (ntsc - tsc);
 			} else
 				max_loops--;

arch/x86/kernel/cpu/amd.c

···
 		const int K6_BUG_LOOP = 1000000;
 		int n;
 		void (*f_vide)(void);
-		unsigned long d, d2;
+		u64 d, d2;
 
 		printk(KERN_INFO "AMD K6 stepping B detected - ");
 
···
 
 		n = K6_BUG_LOOP;
 		f_vide = vide;
-		rdtscl(d);
+		d = rdtsc();
 		while (n--)
 			f_vide();
-		rdtscl(d2);
+		d2 = rdtsc();
 		d = d2-d;
 
 		if (d > 20*K6_BUG_LOOP)

arch/x86/kernel/cpu/mcheck/mce.c

···
 {
 	memset(m, 0, sizeof(struct mce));
 	m->cpu = m->extcpu = smp_processor_id();
-	rdtscll(m->tsc);
+	m->tsc = rdtsc();
 	/* We hope get_seconds stays lockless */
 	m->time = get_seconds();
 	m->cpuvendor = boot_cpu_data.x86_vendor;
···
 {
 	struct mca_config *cfg = &mca_cfg;
 	struct mce m, *final;
-	enum ctx_state prev_state;
 	int i;
 	int worst = 0;
 	int severity;
···
 	int flags = MF_ACTION_REQUIRED;
 	int lmce = 0;
 
-	prev_state = ist_enter(regs);
+	ist_enter(regs);
 
 	this_cpu_inc(mce_exception_count);
 
···
 	local_irq_disable();
 	ist_end_non_atomic();
 done:
-	ist_exit(regs, prev_state);
+	ist_exit(regs);
 }
 EXPORT_SYMBOL_GPL(do_machine_check);
 
···
 {
 	unsigned long *cpu_tsc = (unsigned long *)data;
 
-	rdtscll(cpu_tsc[smp_processor_id()]);
+	cpu_tsc[smp_processor_id()] = rdtsc();
 }
 
 static int mce_apei_read_done;

arch/x86/kernel/cpu/mcheck/p5.c

···
 /* Machine check handler for Pentium class Intel CPUs: */
 static void pentium_machine_check(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state;
 	u32 loaddr, hi, lotype;
 
-	prev_state = ist_enter(regs);
+	ist_enter(regs);
 
 	rdmsr(MSR_IA32_P5_MC_ADDR, loaddr, hi);
 	rdmsr(MSR_IA32_P5_MC_TYPE, lotype, hi);
···
 
 	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
 
-	ist_exit(regs, prev_state);
+	ist_exit(regs);
 }
 
 /* Set up machine check reporting for processors with Intel style MCE: */

arch/x86/kernel/cpu/mcheck/winchip.c

···
 /* Machine check handler for WinChip C6: */
 static void winchip_machine_check(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state = ist_enter(regs);
+	ist_enter(regs);
 
 	printk(KERN_EMERG "CPU0: Machine Check Exception.\n");
 	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
 
-	ist_exit(regs, prev_state);
+	ist_exit(regs);
 }
 
 /* Set up machine check reporting on the Winchip C6 series */

arch/x86/kernel/cpu/perf_event.c

···
 	int idx = segment >> 3;
 
 	if ((segment & SEGMENT_TI_MASK) == SEGMENT_LDT) {
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
 		struct ldt_struct *ldt;
 
 		if (idx > LDT_ENTRIES)
···
 			return 0;
 
 		desc = &ldt->entries[idx];
+#else
+		return 0;
+#endif
 	} else {
 		if (idx > GDT_ENTRIES)
 			return 0;
···
 	return get_desc_base(desc);
 }
 
-#ifdef CONFIG_COMPAT
+#ifdef CONFIG_IA32_EMULATION
 
 #include <asm/compat.h>
 

arch/x86/kernel/espfix_64.c

···
 	 */
 	if (!arch_get_random_long(&rand)) {
 		/* The constant is an arbitrary large prime */
-		rdtscll(rand);
+		rand = rdtsc();
 		rand *= 0xc345c6b72fd16123UL;
 	}
 

arch/x86/kernel/hpet.c

···
 
 	/* Verify whether hpet counter works */
 	t1 = hpet_readl(HPET_COUNTER);
-	rdtscll(start);
+	start = rdtsc();
 
 	/*
 	 * We don't know the TSC frequency yet, but waiting for
···
 	 */
 	do {
 		rep_nop();
-		rdtscll(now);
+		now = rdtsc();
 	} while ((now - start) < 200000UL);
 
 	if (t1 == hpet_readl(HPET_COUNTER)) {

arch/x86/kernel/irq.c

···
 	unsigned vector = ~regs->orig_ax;
 	unsigned irq;
 
+	/*
+	 * NB: Unlike exception entries, IRQ entries do not reliably
+	 * handle context tracking in the low-level entry code.  This is
+	 * because syscall entries execute briefly with IRQs on before
+	 * updating context tracking state, so we can take an IRQ from
+	 * kernel mode with CONTEXT_USER.  The low-level entry code only
+	 * updates the context if we came from user mode, so we won't
+	 * switch to CONTEXT_KERNEL.  We'll fix that once the syscall
+	 * code is cleaned up enough that we can cleanly defer enabling
+	 * IRQs.
+	 */
+
 	entering_irq();
+
+	/* entering_irq() tells RCU that we're not quiescent.  Check it. */
+	rcu_lockdep_assert(rcu_is_watching(), "IRQ failed to wake up RCU");
 
 	irq = __this_cpu_read(vector_irq[vector]);
 

arch/x86/kernel/nmi.c

···
 		a->handler, whole_msecs, decimal_msecs);
 }
 
-static int nmi_handle(unsigned int type, struct pt_regs *regs, bool b2b)
+static int nmi_handle(unsigned int type, struct pt_regs *regs)
 {
 	struct nmi_desc *desc = nmi_to_desc(type);
 	struct nmiaction *a;
···
 pci_serr_error(unsigned char reason, struct pt_regs *regs)
 {
 	/* check to see if anyone registered against these types of errors */
-	if (nmi_handle(NMI_SERR, regs, false))
+	if (nmi_handle(NMI_SERR, regs))
 		return;
 
 	pr_emerg("NMI: PCI system error (SERR) for reason %02x on CPU %d.\n",
···
 	unsigned long i;
 
 	/* check to see if anyone registered against these types of errors */
-	if (nmi_handle(NMI_IO_CHECK, regs, false))
+	if (nmi_handle(NMI_IO_CHECK, regs))
 		return;
 
 	pr_emerg(
···
 	 * as only the first one is ever run (unless it can actually determine
 	 * if it caused the NMI)
 	 */
-	handled = nmi_handle(NMI_UNKNOWN, regs, false);
+	handled = nmi_handle(NMI_UNKNOWN, regs);
 	if (handled) {
 		__this_cpu_add(nmi_stats.unknown, handled);
 		return;
···
 
 	__this_cpu_write(last_nmi_rip, regs->ip);
 
-	handled = nmi_handle(NMI_LOCAL, regs, b2b);
+	handled = nmi_handle(NMI_LOCAL, regs);
 	__this_cpu_add(nmi_stats.normal, handled);
 	if (handled) {
 		/*

arch/x86/kernel/paravirt.c

···
 	.wbinvd = native_wbinvd,
 	.read_msr = native_read_msr_safe,
 	.write_msr = native_write_msr_safe,
-	.read_tsc = native_read_tsc,
 	.read_pmc = native_read_pmc,
-	.read_tscp = native_read_tscp,
 	.load_tr_desc = native_load_tr_desc,
 	.set_ldt = native_set_ldt,
 	.load_gdt = native_load_gdt,

arch/x86/kernel/paravirt_patch_32.c

···
 DEF_NATIVE(pv_mmu_ops, write_cr3, "mov %eax, %cr3");
 DEF_NATIVE(pv_mmu_ops, read_cr3, "mov %cr3, %eax");
 DEF_NATIVE(pv_cpu_ops, clts, "clts");
-DEF_NATIVE(pv_cpu_ops, read_tsc, "rdtsc");
 
 #if defined(CONFIG_PARAVIRT_SPINLOCKS) && defined(CONFIG_QUEUED_SPINLOCKS)
 DEF_NATIVE(pv_lock_ops, queued_spin_unlock, "movb $0, (%eax)");
···
 		PATCH_SITE(pv_mmu_ops, read_cr3);
 		PATCH_SITE(pv_mmu_ops, write_cr3);
 		PATCH_SITE(pv_cpu_ops, clts);
-		PATCH_SITE(pv_cpu_ops, read_tsc);
 #if defined(CONFIG_PARAVIRT_SPINLOCKS) && defined(CONFIG_QUEUED_SPINLOCKS)
 		case PARAVIRT_PATCH(pv_lock_ops.queued_spin_unlock):
 			if (pv_is_native_spin_unlock()) {

arch/x86/kernel/process.c

···
 #include <asm/debugreg.h>
 #include <asm/nmi.h>
 #include <asm/tlbflush.h>
+#include <asm/vm86.h>
 
 /*
  * per-CPU TSS segments. Threads are completely 'soft' on Linux,
···
 		put_cpu();
 		kfree(bp);
 	}
+
+	free_vm86(t);
 
 	fpu__drop(fpu);
 }

arch/x86/kernel/process_32.c

···
 #include <asm/syscalls.h>
 #include <asm/debugreg.h>
 #include <asm/switch_to.h>
+#include <asm/vm86.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");

arch/x86/kernel/process_64.c

···
 void release_thread(struct task_struct *dead_task)
 {
 	if (dead_task->mm) {
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
 		if (dead_task->mm->context.ldt) {
 			pr_warn("WARNING: dead process %s still has LDT? <%p/%d>\n",
 				dead_task->comm,
···
 				dead_task->mm->context.ldt->size);
 			BUG();
 		}
+#endif
 	}
 }
 
···
 			    __USER_CS, __USER_DS, 0);
 }
 
-#ifdef CONFIG_IA32_EMULATION
-void start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp)
+#ifdef CONFIG_COMPAT
+void compat_start_thread(struct pt_regs *regs, u32 new_ip, u32 new_sp)
 {
 	start_thread_common(regs, new_ip, new_sp,
 			    test_thread_flag(TIF_X32)

arch/x86/kernel/ptrace.c

···
 #include <asm/proto.h>
 #include <asm/hw_breakpoint.h>
 #include <asm/traps.h>
+#include <asm/syscall.h>
 
 #include "tls.h"
-
-#define CREATE_TRACE_POINTS
-#include <trace/events/syscalls.h>
 
 enum x86_regset {
 	REGSET_GENERAL,
···
 	return ret;
 }
 
+static long ia32_arch_ptrace(struct task_struct *child, compat_long_t request,
+			     compat_ulong_t caddr, compat_ulong_t cdata)
+{
+	unsigned long addr = caddr;
+	unsigned long data = cdata;
+	void __user *datap = compat_ptr(data);
+	int ret;
+	__u32 val;
+
+	switch (request) {
+	case PTRACE_PEEKUSR:
+		ret = getreg32(child, addr, &val);
+		if (ret == 0)
+			ret = put_user(val, (__u32 __user *)datap);
+		break;
+
+	case PTRACE_POKEUSR:
+		ret = putreg32(child, addr, data);
+		break;
+
+	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
+		return copy_regset_to_user(child, &user_x86_32_view,
+					   REGSET_GENERAL,
+					   0, sizeof(struct user_regs_struct32),
+					   datap);
+
+	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
+		return copy_regset_from_user(child, &user_x86_32_view,
+					     REGSET_GENERAL, 0,
+					     sizeof(struct user_regs_struct32),
+					     datap);
+
+	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
+		return copy_regset_to_user(child, &user_x86_32_view,
+					   REGSET_FP, 0,
+					   sizeof(struct user_i387_ia32_struct),
+					   datap);
+
+	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
+		return copy_regset_from_user(
+			child, &user_x86_32_view, REGSET_FP,
+			0, sizeof(struct user_i387_ia32_struct), datap);
+
+	case PTRACE_GETFPXREGS:	/* Get the child extended FPU state. */
+		return copy_regset_to_user(child, &user_x86_32_view,
+					   REGSET_XFP, 0,
+					   sizeof(struct user32_fxsr_struct),
+					   datap);
+
+	case PTRACE_SETFPXREGS:	/* Set the child extended FPU state. */
+		return copy_regset_from_user(child, &user_x86_32_view,
+					     REGSET_XFP, 0,
+					     sizeof(struct user32_fxsr_struct),
+					     datap);
+
+	case PTRACE_GET_THREAD_AREA:
+	case PTRACE_SET_THREAD_AREA:
+		return arch_ptrace(child, request, addr, data);
+
+	default:
+		return compat_ptrace_request(child, request, addr, data);
+	}
+
+	return ret;
+}
+#endif /* CONFIG_IA32_EMULATION */
+
 #ifdef CONFIG_X86_X32_ABI
 static long x32_arch_ptrace(struct task_struct *child,
 			    compat_long_t request, compat_ulong_t caddr,
···
 }
 #endif
 
+#ifdef CONFIG_COMPAT
 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 			compat_ulong_t caddr, compat_ulong_t cdata)
 {
-	unsigned long addr = caddr;
-	unsigned long data = cdata;
-	void __user *datap = compat_ptr(data);
-	int ret;
-	__u32 val;
-
 #ifdef CONFIG_X86_X32_ABI
 	if (!is_ia32_task())
 		return x32_arch_ptrace(child, request, caddr, cdata);
 #endif
-
-	switch (request) {
-	case PTRACE_PEEKUSR:
-		ret = getreg32(child, addr, &val);
-		if (ret == 0)
-			ret = put_user(val, (__u32 __user *)datap);
-		break;
-
-	case PTRACE_POKEUSR:
-		ret = putreg32(child, addr, data);
-		break;
-
-	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
-		return copy_regset_to_user(child, &user_x86_32_view,
-					   REGSET_GENERAL,
-					   0, sizeof(struct user_regs_struct32),
-					   datap);
-
-	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
-		return copy_regset_from_user(child, &user_x86_32_view,
-					     REGSET_GENERAL, 0,
-					     sizeof(struct user_regs_struct32),
-					     datap);
-
-	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
-		return copy_regset_to_user(child, &user_x86_32_view,
-					   REGSET_FP, 0,
-					   sizeof(struct user_i387_ia32_struct),
-					   datap);
-
-	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
-		return copy_regset_from_user(
-			child, &user_x86_32_view, REGSET_FP,
-			0, sizeof(struct user_i387_ia32_struct), datap);
-
-	case PTRACE_GETFPXREGS:	/* Get the child extended FPU state. */
-		return copy_regset_to_user(child, &user_x86_32_view,
-					   REGSET_XFP, 0,
-					   sizeof(struct user32_fxsr_struct),
-					   datap);
-
-	case PTRACE_SETFPXREGS:	/* Set the child extended FPU state. */
-		return copy_regset_from_user(child, &user_x86_32_view,
-					     REGSET_XFP, 0,
-					     sizeof(struct user32_fxsr_struct),
-					     datap);
-
-	case PTRACE_GET_THREAD_AREA:
-	case PTRACE_SET_THREAD_AREA:
-		return arch_ptrace(child, request, addr, data);
-
-	default:
-		return compat_ptrace_request(child, request, addr, data);
-	}
-
-	return ret;
+#ifdef CONFIG_IA32_EMULATION
+	return ia32_arch_ptrace(child, request, caddr, cdata);
+#else
+	return 0;
+#endif
 }
-
-#endif	/* CONFIG_IA32_EMULATION */
+#endif	/* CONFIG_COMPAT */
 
 #ifdef CONFIG_X86_64
 
···
 	fill_sigtrap_info(tsk, regs, error_code, si_code, &info);
 	/* Send us the fake SIGTRAP */
 	force_sig_info(SIGTRAP, &info, tsk);
-}
-
-static void do_audit_syscall_entry(struct pt_regs *regs, u32 arch)
-{
-#ifdef CONFIG_X86_64
-	if (arch == AUDIT_ARCH_X86_64) {
-		audit_syscall_entry(regs->orig_ax, regs->di,
-				    regs->si, regs->dx, regs->r10);
-	} else
-#endif
-	{
-		audit_syscall_entry(regs->orig_ax, regs->bx,
-				    regs->cx, regs->dx, regs->si);
-	}
-}
-
-/*
- * We can return 0 to resume the syscall or anything else to go to phase
- * 2.  If we resume the syscall, we need to put something appropriate in
- * regs->orig_ax.
- *
- * NB: We don't have full pt_regs here, but regs->orig_ax and regs->ax
- * are fully functional.
- *
- * For phase 2's benefit, our return value is:
- * 0:			resume the syscall
- * 1:			go to phase 2; no seccomp phase 2 needed
- * anything else:	go to phase 2; pass return value to seccomp
- */
-unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)
-{
-	unsigned long ret = 0;
-	u32 work;
-
-	BUG_ON(regs != task_pt_regs(current));
-
-	work = ACCESS_ONCE(current_thread_info()->flags) &
-		_TIF_WORK_SYSCALL_ENTRY;
-
-	/*
-	 * If TIF_NOHZ is set, we are required to call user_exit() before
-	 * doing anything that could touch RCU.
-	 */
-	if (work & _TIF_NOHZ) {
-		user_exit();
-		work &= ~_TIF_NOHZ;
-	}
-
-#ifdef CONFIG_SECCOMP
-	/*
-	 * Do seccomp first -- it should minimize exposure of other
-	 * code, and keeping seccomp fast is probably more valuable
-	 * than the rest of this.
-	 */
-	if (work & _TIF_SECCOMP) {
-		struct seccomp_data sd;
-
-		sd.arch = arch;
-		sd.nr = regs->orig_ax;
-		sd.instruction_pointer = regs->ip;
-#ifdef CONFIG_X86_64
-		if (arch == AUDIT_ARCH_X86_64) {
-			sd.args[0] = regs->di;
-			sd.args[1] = regs->si;
-			sd.args[2] = regs->dx;
-			sd.args[3] = regs->r10;
-			sd.args[4] = regs->r8;
-			sd.args[5] = regs->r9;
-		} else
-#endif
-		{
-			sd.args[0] = regs->bx;
-			sd.args[1] = regs->cx;
-			sd.args[2] = regs->dx;
-			sd.args[3] = regs->si;
-			sd.args[4] = regs->di;
-			sd.args[5] = regs->bp;
-		}
-
-		BUILD_BUG_ON(SECCOMP_PHASE1_OK != 0);
-		BUILD_BUG_ON(SECCOMP_PHASE1_SKIP != 1);
-
-		ret = seccomp_phase1(&sd);
-		if (ret == SECCOMP_PHASE1_SKIP) {
-			regs->orig_ax = -1;
-			ret = 0;
-		} else if (ret != SECCOMP_PHASE1_OK) {
-			return ret;  /* Go directly to phase 2 */
-		}
-
-		work &= ~_TIF_SECCOMP;
-	}
-#endif
-
-	/* Do our best to finish without phase 2. */
-	if (work == 0)
-		return ret;  /* seccomp and/or nohz only (ret == 0 here) */
-
-#ifdef CONFIG_AUDITSYSCALL
-	if (work == _TIF_SYSCALL_AUDIT) {
-		/*
-		 * If there is no more work to be done except auditing,
-		 * then audit in phase 1.  Phase 2 always audits, so, if
-		 * we audit here, then we can't go on to phase 2.
-		 */
-		do_audit_syscall_entry(regs, arch);
-		return 0;
-	}
-#endif
-
-	return 1;  /* Something is enabled that we can't handle in phase 1 */
-}
-
-/* Returns the syscall nr to run (which should match regs->orig_ax). */
-long syscall_trace_enter_phase2(struct pt_regs *regs, u32 arch,
-				unsigned long phase1_result)
-{
-	long ret = 0;
-	u32 work = ACCESS_ONCE(current_thread_info()->flags) &
-		_TIF_WORK_SYSCALL_ENTRY;
-
-	BUG_ON(regs != task_pt_regs(current));
-
-	/*
-	 * If we stepped into a sysenter/syscall insn, it trapped in
-	 * kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP.
-	 * If user-mode had set TF itself, then it's still clear from
-	 * do_debug() and we need to set it again to restore the user
-	 * state.  If we entered on the slow path, TF was already set.
-	 */
-	if (work & _TIF_SINGLESTEP)
-		regs->flags |= X86_EFLAGS_TF;
-
-#ifdef CONFIG_SECCOMP
-	/*
-	 * Call seccomp_phase2 before running the other hooks so that
-	 * they can see any changes made by a seccomp tracer.
-	 */
-	if (phase1_result > 1 && seccomp_phase2(phase1_result)) {
-		/* seccomp failures shouldn't expose any additional code. */
-		return -1;
-	}
-#endif
-
-	if (unlikely(work & _TIF_SYSCALL_EMU))
-		ret = -1L;
-
-	if ((ret || test_thread_flag(TIF_SYSCALL_TRACE)) &&
-	    tracehook_report_syscall_entry(regs))
-		ret = -1L;
-
-	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
-		trace_sys_enter(regs, regs->orig_ax);
-
-	do_audit_syscall_entry(regs, arch);
-
-	return ret ?: regs->orig_ax;
-}
-
-long syscall_trace_enter(struct pt_regs *regs)
-{
-	u32 arch = is_ia32_task() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
-	unsigned long phase1_result = syscall_trace_enter_phase1(regs, arch);
-
-	if (phase1_result == 0)
-		return regs->orig_ax;
-	else
-		return syscall_trace_enter_phase2(regs, arch, phase1_result);
-}
-
-void syscall_trace_leave(struct pt_regs *regs)
-{
-	bool step;
-
-	/*
-	 * We may come here right after calling schedule_user()
-	 * or do_notify_resume(), in which case we can be in RCU
-	 * user mode.
-	 */
-	user_exit();
-
-	audit_syscall_exit(regs);
-
-	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
-		trace_sys_exit(regs, regs->ax);
-
-	/*
-	 * If TIF_SYSCALL_EMU is set, we only get here because of
-	 * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
-	 * We already reported this syscall instruction in
-	 * syscall_trace_enter().
-	 */
-	step = unlikely(test_thread_flag(TIF_SINGLESTEP)) &&
-			!test_thread_flag(TIF_SYSCALL_EMU);
-	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
-		tracehook_report_syscall_exit(regs, step);
-
-	user_enter();
 }

arch/x86/kernel/signal.c

···
 #include <asm/vdso.h>
 #include <asm/mce.h>
 #include <asm/sighandling.h>
+#include <asm/vm86.h>
 
 #ifdef CONFIG_X86_64
 #include <asm/proto.h>
 #include <asm/ia32_unistd.h>
-#include <asm/sys_ia32.h>
 #endif /* CONFIG_X86_64 */
 
 #include <asm/syscall.h>
···
 	bool stepping, failed;
 	struct fpu *fpu = &current->thread.fpu;
 
+	if (v8086_mode(regs))
+		save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL);
+
 	/* Are we from a system call? */
 	if (syscall_get_nr(current, regs) >= 0) {
 		/* If so, check system call restarting.. */
···
  * want to handle. Thus you cannot kill init even with a SIGKILL even by
  * mistake.
  */
-static void do_signal(struct pt_regs *regs)
+void do_signal(struct pt_regs *regs)
 {
 	struct ksignal ksig;
 
···
 	 * back.
 	 */
 	restore_saved_sigmask();
-}
-
-/*
- * notification of userspace execution resumption
- * - triggered by the TIF_WORK_MASK flags
- */
-__visible void
-do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
-{
-	user_exit();
-
-	if (thread_info_flags & _TIF_UPROBE)
-		uprobe_notify_resume(regs);
-
-	/* deal with pending signal delivery */
-	if (thread_info_flags & _TIF_SIGPENDING)
-		do_signal(regs);
-
-	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
-		clear_thread_flag(TIF_NOTIFY_RESUME);
-		tracehook_notify_resume(regs);
-	}
-	if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
-		fire_user_return_notifiers();
-
-	user_enter();
 }
 
 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)

arch/x86/kernel/signal_compat.c

···
+#include <linux/compat.h>
+#include <linux/uaccess.h>
+
+int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
+{
+	int err = 0;
+	bool ia32 = test_thread_flag(TIF_IA32);
+
+	if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
+		return -EFAULT;
+
+	put_user_try {
+		/* If you change siginfo_t structure, please make sure that
+		   this code is fixed accordingly.
+		   It should never copy any pad contained in the structure
+		   to avoid security leaks, but must copy the generic
+		   3 ints plus the relevant union member.  */
+		put_user_ex(from->si_signo, &to->si_signo);
+		put_user_ex(from->si_errno, &to->si_errno);
+		put_user_ex((short)from->si_code, &to->si_code);
+
+		if (from->si_code < 0) {
+			put_user_ex(from->si_pid, &to->si_pid);
+			put_user_ex(from->si_uid, &to->si_uid);
+			put_user_ex(ptr_to_compat(from->si_ptr), &to->si_ptr);
+		} else {
+			/*
+			 * First 32bits of unions are always present:
+			 * si_pid === si_band === si_tid === si_addr(LS half)
+			 */
+			put_user_ex(from->_sifields._pad[0],
+					  &to->_sifields._pad[0]);
+			switch (from->si_code >> 16) {
+			case __SI_FAULT >> 16:
+				break;
+			case __SI_SYS >> 16:
+				put_user_ex(from->si_syscall, &to->si_syscall);
+				put_user_ex(from->si_arch, &to->si_arch);
+				break;
+			case __SI_CHLD >> 16:
+				if (ia32) {
+					put_user_ex(from->si_utime, &to->si_utime);
+					put_user_ex(from->si_stime, &to->si_stime);
+				} else {
+					put_user_ex(from->si_utime, &to->_sifields._sigchld_x32._utime);
+					put_user_ex(from->si_stime, &to->_sifields._sigchld_x32._stime);
+				}
+				put_user_ex(from->si_status, &to->si_status);
+				/* FALL THROUGH */
+			default:
+			case __SI_KILL >> 16:
+				put_user_ex(from->si_uid, &to->si_uid);
+				break;
+			case __SI_POLL >> 16:
+				put_user_ex(from->si_fd, &to->si_fd);
+				break;
+			case __SI_TIMER >> 16:
+				put_user_ex(from->si_overrun, &to->si_overrun);
+				put_user_ex(ptr_to_compat(from->si_ptr),
+					    &to->si_ptr);
+				break;
+				 /* This is not generated by the kernel as of now.  */
+			case __SI_RT >> 16:
+			case __SI_MESGQ >> 16:
+				put_user_ex(from->si_uid, &to->si_uid);
+				put_user_ex(from->si_int, &to->si_int);
+				break;
+			}
+		}
+	} put_user_catch(err);
+
+	return err;
+}
+
+int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
+{
+	int err = 0;
+	u32 ptr32;
+
+	if (!access_ok(VERIFY_READ, from, sizeof(compat_siginfo_t)))
+		return -EFAULT;
+
+	get_user_try {
+		get_user_ex(to->si_signo, &from->si_signo);
+		get_user_ex(to->si_errno, &from->si_errno);
+		get_user_ex(to->si_code, &from->si_code);
+
+		get_user_ex(to->si_pid, &from->si_pid);
+		get_user_ex(to->si_uid, &from->si_uid);
+		get_user_ex(ptr32, &from->si_ptr);
+		to->si_ptr = compat_ptr(ptr32);
+	} get_user_catch(err);
+
+	return err;
+}

arch/x86/kernel/step.c

···
 		return addr;
 	}
 
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
 	/*
 	 * We'll assume that the code segments in the GDT
 	 * are all zero-based. That is largely true: the
···
 		}
 		mutex_unlock(&child->mm->context.lock);
 	}
+#endif
 
 	return addr;
 }

arch/x86/kernel/trace_clock.c

···
  */
 u64 notrace trace_clock_x86_tsc(void)
 {
-	u64 ret;
-
-	rdtsc_barrier();
-	rdtscll(ret);
-
-	return ret;
+	return rdtsc_ordered();
 }

arch/x86/kernel/traps.c

···
 #include <asm/fpu/xstate.h>
 #include <asm/trace/mpx.h>
 #include <asm/mpx.h>
+#include <asm/vm86.h>
 
 #ifdef CONFIG_X86_64
 #include <asm/x86_init.h>
···
 	preempt_count_dec();
 }
 
-enum ctx_state ist_enter(struct pt_regs *regs)
+void ist_enter(struct pt_regs *regs)
 {
-	enum ctx_state prev_state;
-
 	if (user_mode(regs)) {
-		/* Other than that, we're just an exception. */
-		prev_state = exception_enter();
+		CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	} else {
 		/*
 		 * We might have interrupted pretty much anything.  In
···
 		 * but we need to notify RCU.
 		 */
 		rcu_nmi_enter();
-		prev_state = CONTEXT_KERNEL;  /* the value is irrelevant. */
 	}
 
 	/*
-	 * We are atomic because we're on the IST stack (or we're on x86_32,
-	 * in which case we still shouldn't schedule).
-	 *
-	 * This must be after exception_enter(), because exception_enter()
-	 * won't do anything if in_interrupt() returns true.
+	 * We are atomic because we're on the IST stack; or we're on
+	 * x86_32, in which case we still shouldn't schedule; or we're
+	 * on x86_64 and entered from user mode, in which case we're
+	 * still atomic unless ist_begin_non_atomic is called.
 	 */
 	preempt_count_add(HARDIRQ_OFFSET);
 
 	/* This code is a bit fragile.  Test it. */
 	rcu_lockdep_assert(rcu_is_watching(), "ist_enter didn't work");
-
-	return prev_state;
 }
 
-void ist_exit(struct pt_regs *regs, enum ctx_state prev_state)
+void ist_exit(struct pt_regs *regs)
 {
-	/* Must be before exception_exit. */
 	preempt_count_sub(HARDIRQ_OFFSET);
 
-	if (user_mode(regs))
-		return exception_exit(prev_state);
-	else
+	if (!user_mode(regs))
 		rcu_nmi_exit();
 }
 
···
  * a double fault, it can be safe to schedule.  ist_begin_non_atomic()
  * begins a non-atomic section within an ist_enter()/ist_exit() region.
  * Callers are responsible for enabling interrupts themselves inside
- * the non-atomic section, and callers must call is_end_non_atomic()
+ * the non-atomic section, and callers must call ist_end_non_atomic()
  * before ist_exit().
  */
 void ist_begin_non_atomic(struct pt_regs *regs)
···
 static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
 			  unsigned long trapnr, int signr)
 {
-	enum ctx_state prev_state = exception_enter();
 	siginfo_t info;
+
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 
 	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
 			NOTIFY_STOP) {
···
 		do_trap(trapnr, signr, str, regs, error_code,
 			fill_trap_info(regs, signr, trapnr, &info));
 	}
-
-	exception_exit(prev_state);
 }
 
 #define DO_ERROR(trapnr, signr, str, name)				\
···
 	}
 #endif
 
-	ist_enter(regs);  /* Discard prev_state because we won't return. */
+	ist_enter(regs);
 	notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
 
 	tsk->thread.error_code = error_code;
···
 
 dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state;
 	const struct bndcsr *bndcsr;
 	siginfo_t *info;
 
-	prev_state = exception_enter();
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	if (notify_die(DIE_TRAP, "bounds", regs, error_code,
 			X86_TRAP_BR, SIGSEGV) == NOTIFY_STOP)
-		goto exit;
+		return;
 	conditional_sti(regs);
 
 	if (!user_mode(regs))
···
 		die("bounds", regs, error_code);
 	}
 
-exit:
-	exception_exit(prev_state);
 	return;
+
 exit_trap:
 	/*
 	 * This path out is for all the cases where we could not
···
 	 * time..
 	 */
 	do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code, NULL);
-	exception_exit(prev_state);
 }
 
 dotraplinkage void
 do_general_protection(struct pt_regs *regs, long error_code)
 {
 	struct task_struct *tsk;
-	enum ctx_state prev_state;
 
-	prev_state = exception_enter();
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	conditional_sti(regs);
 
 	if (v8086_mode(regs)) {
 		local_irq_enable();
 		handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
-		goto exit;
+		return;
 	}
 
 	tsk = current;
 	if (!user_mode(regs)) {
 		if (fixup_exception(regs))
-			goto exit;
+			return;
 
 		tsk->thread.error_code = error_code;
 		tsk->thread.trap_nr = X86_TRAP_GP;
 		if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
 			       X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP)
 			die("general protection fault", regs, error_code);
-		goto exit;
+		return;
 	}
 
 	tsk->thread.error_code = error_code;
···
 	}
 
 	force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
-exit:
-	exception_exit(prev_state);
 }
 NOKPROBE_SYMBOL(do_general_protection);
 
 /* May run on IST stack. */
 dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state;
-
 #ifdef CONFIG_DYNAMIC_FTRACE
 	/*
 	 * ftrace must be first, everything else may cause a recursive crash.
···
 	if (poke_int3_handler(regs))
 		return;
 
-	prev_state = ist_enter(regs);
+	ist_enter(regs);
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
 	if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
 				SIGTRAP) == NOTIFY_STOP)
···
 	preempt_conditional_cli(regs);
 	debug_stack_usage_dec();
 exit:
-	ist_exit(regs, prev_state);
+	ist_exit(regs);
 }
 NOKPROBE_SYMBOL(do_int3);
 
···
 dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
 {
 	struct task_struct *tsk = current;
-	enum ctx_state prev_state;
 	int user_icebp = 0;
 	unsigned long dr6;
 	int si_code;
 
-	prev_state = ist_enter(regs);
+	ist_enter(regs);
 
 	get_debugreg(dr6, 6);
 
···
 	debug_stack_usage_dec();
 
 exit:
-	ist_exit(regs, prev_state);
+	ist_exit(regs);
 }
 NOKPROBE_SYMBOL(do_debug);
 
···
 
 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state;
-
-	prev_state = exception_enter();
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	math_error(regs, error_code, X86_TRAP_MF);
-	exception_exit(prev_state);
 }
 
 dotraplinkage void
 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state;
-
-	prev_state = exception_enter();
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	math_error(regs, error_code, X86_TRAP_XF);
-	exception_exit(prev_state);
 }
 
 dotraplinkage void
···
 dotraplinkage void
 do_device_not_available(struct pt_regs *regs, long error_code)
 {
-	enum ctx_state prev_state;
-
-	prev_state = exception_enter();
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	BUG_ON(use_eager_fpu());
 
 #ifdef CONFIG_MATH_EMULATION
···
 
 		info.regs = regs;
 		math_emulate(&info);
-		exception_exit(prev_state);
 		return;
 	}
 #endif
···
 #ifdef CONFIG_X86_32
 	conditional_sti(regs);
 #endif
-	exception_exit(prev_state);
 }
 NOKPROBE_SYMBOL(do_device_not_available);
 
···
 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 {
 	siginfo_t info;
-	enum ctx_state prev_state;
 
-	prev_state = exception_enter();
+	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
 	local_irq_enable();
 
 	info.si_signo = SIGILL;
···
 		do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
 			&info);
 	}
-	exception_exit(prev_state);
 }
 #endif
 

arch/x86/kernel/tsc.c

···
 
 	data = cyc2ns_write_begin(cpu);
 
-	rdtscll(tsc_now);
+	tsc_now = rdtsc();
 	ns_now = cycles_2_ns(tsc_now);
 
 	/*
···
 	}
 
 	/* read the Time Stamp Counter: */
-	rdtscll(tsc_now);
+	tsc_now = rdtsc();
 
 	/* return the value in ns */
 	return cycles_2_ns(tsc_now);
···
 unsigned long long
 sched_clock(void) __attribute__((alias("native_sched_clock")));
 #endif
-
-unsigned long long native_read_tsc(void)
-{
-	return __native_read_tsc();
-}
-EXPORT_SYMBOL(native_read_tsc);
 
 int check_tsc_unstable(void)
 {
···
  */
 static cycle_t read_tsc(struct clocksource *cs)
 {
-	return (cycle_t)get_cycles();
+	return (cycle_t)rdtsc_ordered();
 }
 
 /*

arch/x86/kernel/tsc_sync.c

···
 static int nr_warps;
 
 /*
- * TSC-warp measurement loop running on both CPUs:
+ * TSC-warp measurement loop running on both CPUs.  This is not called
+ * if there is no TSC.
  */
 static void check_tsc_warp(unsigned int timeout)
 {
 	cycles_t start, now, prev, end;
 	int i;
 
-	rdtsc_barrier();
-	start = get_cycles();
-	rdtsc_barrier();
+	start = rdtsc_ordered();
 	/*
 	 * The measurement runs for 'timeout' msecs:
 	 */
···
 		 */
 		arch_spin_lock(&sync_lock);
 		prev = last_tsc;
-		rdtsc_barrier();
-		now = get_cycles();
-		rdtsc_barrier();
+		now = rdtsc_ordered();
 		last_tsc = now;
 		arch_spin_unlock(&sync_lock);
 
···
 
 	/*
 	 * No need to check if we already know that the TSC is not
-	 * synchronized:
+	 * synchronized or if we have no TSC.
 	 */
 	if (unsynchronized_tsc())
 		return;
···
 {
 	int cpus = 2;
 
+	/* Also aborts if there is no TSC. */
 	if (unsynchronized_tsc() || tsc_clocksource_reliable)
 		return;
 

arch/x86/kernel/vm86_32.c

···
 #include <linux/ptrace.h>
 #include <linux/audit.h>
 #include <linux/stddef.h>
+#include <linux/slab.h>
 
 #include <asm/uaccess.h>
 #include <asm/io.h>
 #include <asm/tlbflush.h>
 #include <asm/irq.h>
+#include <asm/traps.h>
+#include <asm/vm86.h>
 
 /*
  * Known problems:
···
  */
 
 
-#define KVM86	((struct kernel_vm86_struct *)regs)
-#define VMPI	KVM86->vm86plus
-
-
 /*
  * 8- and 16-bit register defines..
  */
···
 /*
  * virtual flags (16 and 32-bit versions)
  */
-#define VFLAGS	(*(unsigned short *)&(current->thread.v86flags))
-#define VEFLAGS	(current->thread.v86flags)
+#define VFLAGS	(*(unsigned short *)&(current->thread.vm86->veflags))
+#define VEFLAGS	(current->thread.vm86->veflags)
 
 #define set_flags(X, new, mask) \
 ((X) = ((X) & ~(mask)) | ((new) & (mask)))
···
 #define SAFE_MASK	(0xDD5)
 #define RETURN_MASK	(0xDFF)
 
-/* convert kernel_vm86_regs to vm86_regs */
-static int copy_vm86_regs_to_user(struct vm86_regs __user *user,
-				  const struct kernel_vm86_regs *regs)
-{
-	int ret = 0;
-
-	/*
-	 * kernel_vm86_regs is missing gs, so copy everything up to
-	 * (but not including) orig_eax, and then rest including orig_eax.
-	 */
-	ret += copy_to_user(user, regs, offsetof(struct kernel_vm86_regs, pt.orig_ax));
-	ret += copy_to_user(&user->orig_eax, &regs->pt.orig_ax,
-			    sizeof(struct kernel_vm86_regs) -
-			    offsetof(struct kernel_vm86_regs, pt.orig_ax));
-
-	return ret;
-}
-
-/* convert vm86_regs to kernel_vm86_regs */
-static int copy_vm86_regs_from_user(struct kernel_vm86_regs *regs,
-				    const struct vm86_regs __user *user,
-				    unsigned extra)
-{
-	int ret = 0;
-
-	/* copy ax-fs inclusive */
-	ret += copy_from_user(regs, user, offsetof(struct kernel_vm86_regs, pt.orig_ax));
-	/* copy orig_ax-__gsh+extra */
-	ret += copy_from_user(&regs->pt.orig_ax, &user->orig_eax,
-			      sizeof(struct kernel_vm86_regs) -
-			      offsetof(struct kernel_vm86_regs, pt.orig_ax) +
-			      extra);
-	return ret;
-}
-
-struct pt_regs *save_v86_state(struct kernel_vm86_regs *regs)
+void save_v86_state(struct kernel_vm86_regs *regs, int retval)
 {
 	struct tss_struct *tss;
-	struct pt_regs *ret;
-	unsigned long tmp;
+	struct task_struct *tsk = current;
+	struct vm86plus_struct __user *user;
+	struct vm86 *vm86 = current->thread.vm86;
+	long err = 0;
 
 	/*
 	 * This gets called from entry.S with interrupts disabled, but
···
 	 */
 	local_irq_enable();
 
-	if (!current->thread.vm86_info) {
-		pr_alert("no vm86_info: BAD\n");
+	if (!vm86 || !vm86->user_vm86) {
+		pr_alert("no user_vm86: BAD\n");
 		do_exit(SIGSEGV);
 	}
-	set_flags(regs->pt.flags, VEFLAGS, X86_EFLAGS_VIF | current->thread.v86mask);
-	tmp = copy_vm86_regs_to_user(&current->thread.vm86_info->regs, regs);
-	tmp += put_user(current->thread.screen_bitmap, &current->thread.vm86_info->screen_bitmap);
-	if (tmp) {
-		pr_alert("could not access userspace vm86_info\n");
+	set_flags(regs->pt.flags, VEFLAGS, X86_EFLAGS_VIF | vm86->veflags_mask);
+	user = vm86->user_vm86;
+
+	if (!access_ok(VERIFY_WRITE, user, vm86->vm86plus.is_vm86pus ?
+		       sizeof(struct vm86plus_struct) :
+		       sizeof(struct vm86_struct))) {
+		pr_alert("could not access userspace vm86 info\n");
+		do_exit(SIGSEGV);
+	}
+
+	put_user_try {
+		put_user_ex(regs->pt.bx, &user->regs.ebx);
+		put_user_ex(regs->pt.cx, &user->regs.ecx);
+		put_user_ex(regs->pt.dx, &user->regs.edx);
+		put_user_ex(regs->pt.si, &user->regs.esi);
+		put_user_ex(regs->pt.di, &user->regs.edi);
+		put_user_ex(regs->pt.bp, &user->regs.ebp);
+		put_user_ex(regs->pt.ax, &user->regs.eax);
+		put_user_ex(regs->pt.ip, &user->regs.eip);
+		put_user_ex(regs->pt.cs, &user->regs.cs);
+		put_user_ex(regs->pt.flags, &user->regs.eflags);
+		put_user_ex(regs->pt.sp, &user->regs.esp);
+		put_user_ex(regs->pt.ss, &user->regs.ss);
+		put_user_ex(regs->es, &user->regs.es);
+		put_user_ex(regs->ds, &user->regs.ds);
+		put_user_ex(regs->fs, &user->regs.fs);
+		put_user_ex(regs->gs, &user->regs.gs);
+
+		put_user_ex(vm86->screen_bitmap, &user->screen_bitmap);
+	} put_user_catch(err);
+	if (err) {
+		pr_alert("could not access userspace vm86 info\n");
 		do_exit(SIGSEGV);
 	}
 
 	tss = &per_cpu(cpu_tss, get_cpu());
-	current->thread.sp0 = current->thread.saved_sp0;
-	current->thread.sysenter_cs = __KERNEL_CS;
-	load_sp0(tss, &current->thread);
-	current->thread.saved_sp0 = 0;
+	tsk->thread.sp0 = vm86->saved_sp0;
+	tsk->thread.sysenter_cs = __KERNEL_CS;
+	load_sp0(tss, &tsk->thread);
+	vm86->saved_sp0 = 0;
 	put_cpu();
 
-	ret = KVM86->regs32;
+	memcpy(&regs->pt, &vm86->regs32, sizeof(struct pt_regs));
 
-	ret->fs = current->thread.saved_fs;
-	set_user_gs(ret, current->thread.saved_gs);
+	lazy_load_gs(vm86->regs32.gs);
 
-	return ret;
+	regs->pt.ax = retval;
 }
 
 static void mark_screen_rdonly(struct mm_struct *mm)
···
 
 
 static int do_vm86_irq_handling(int subfunction, int irqnumber);
-static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk);
+static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus);
 
-SYSCALL_DEFINE1(vm86old, struct vm86_struct __user *, v86)
+SYSCALL_DEFINE1(vm86old, struct vm86_struct __user *, user_vm86)
 {
-	struct kernel_vm86_struct info; /* declare this _on top_,
-					 * this avoids wasting of stack space.
-					 * This remains on the stack until we
-					 * return to 32 bit user space.
-					 */
-	struct task_struct *tsk = current;
-	int tmp;
-
-	if (tsk->thread.saved_sp0)
-		return -EPERM;
-	tmp = copy_vm86_regs_from_user(&info.regs, &v86->regs,
-				       offsetof(struct kernel_vm86_struct, vm86plus) -
-				       sizeof(info.regs));
-	if (tmp)
-		return -EFAULT;
-	memset(&info.vm86plus, 0, (int)&info.regs32 - (int)&info.vm86plus);
-	info.regs32 = current_pt_regs();
-	tsk->thread.vm86_info = v86;
-	do_sys_vm86(&info, tsk);
-	return 0;	/* we never return here */
+	return do_sys_vm86((struct vm86plus_struct __user *) user_vm86, false);
 }
 
 
 SYSCALL_DEFINE2(vm86, unsigned long, cmd, unsigned long, arg)
 {
-	struct kernel_vm86_struct info; /* declare this _on top_,
-					 * this avoids wasting of stack space.
-					 * This remains on the stack until we
-					 * return to 32 bit user space.
-					 */
-	struct task_struct *tsk;
-	int tmp;
-	struct vm86plus_struct __user *v86;
-
-	tsk = current;
 	switch (cmd) {
 	case VM86_REQUEST_IRQ:
 	case VM86_FREE_IRQ:
···
 	}
 
 	/* we come here only for functions VM86_ENTER, VM86_ENTER_NO_BYPASS */
-	if (tsk->thread.saved_sp0)
-		return -EPERM;
-	v86 = (struct vm86plus_struct __user *)arg;
-	tmp = copy_vm86_regs_from_user(&info.regs, &v86->regs,
-				       offsetof(struct kernel_vm86_struct, regs32) -
-				       sizeof(info.regs));
-	if (tmp)
-		return -EFAULT;
-	info.regs32 = current_pt_regs();
-	info.vm86plus.is_vm86pus = 1;
-	tsk->thread.vm86_info = (struct vm86_struct __user *)v86;
-	do_sys_vm86(&info, tsk);
-	return 0;	/* we never return here */
+	return do_sys_vm86((struct vm86plus_struct __user *) arg, true);
 }
 
 
-static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk)
+static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
 {
 	struct tss_struct *tss;
-/*
- * make sure the vm86() system call doesn't try to do anything silly
- */
-	info->regs.pt.ds = 0;
-	info->regs.pt.es = 0;
-	info->regs.pt.fs = 0;
-#ifndef CONFIG_X86_32_LAZY_GS
-	info->regs.pt.gs = 0;
-#endif
+	struct task_struct *tsk = current;
+	struct vm86 *vm86 = tsk->thread.vm86;
+	struct kernel_vm86_regs vm86regs;
+	struct pt_regs *regs = current_pt_regs();
+	unsigned long err = 0;
+
+	if (!vm86) {
+		if (!(vm86 = kzalloc(sizeof(*vm86), GFP_KERNEL)))
+			return -ENOMEM;
+		tsk->thread.vm86 = vm86;
+	}
+	if (vm86->saved_sp0)
+		return -EPERM;
+
+	if (!access_ok(VERIFY_READ, user_vm86, plus ?
+		       sizeof(struct vm86_struct) :
+		       sizeof(struct vm86plus_struct)))
+		return -EFAULT;
+
+	memset(&vm86regs, 0, sizeof(vm86regs));
+	get_user_try {
+		unsigned short seg;
+		get_user_ex(vm86regs.pt.bx, &user_vm86->regs.ebx);
+		get_user_ex(vm86regs.pt.cx, &user_vm86->regs.ecx);
+		get_user_ex(vm86regs.pt.dx, &user_vm86->regs.edx);
+		get_user_ex(vm86regs.pt.si, &user_vm86->regs.esi);
+		get_user_ex(vm86regs.pt.di, &user_vm86->regs.edi);
+		get_user_ex(vm86regs.pt.bp, &user_vm86->regs.ebp);
+		get_user_ex(vm86regs.pt.ax, &user_vm86->regs.eax);
+		get_user_ex(vm86regs.pt.ip, &user_vm86->regs.eip);
+		get_user_ex(seg, &user_vm86->regs.cs);
+		vm86regs.pt.cs = seg;
+		get_user_ex(vm86regs.pt.flags, &user_vm86->regs.eflags);
+		get_user_ex(vm86regs.pt.sp, &user_vm86->regs.esp);
+		get_user_ex(seg, &user_vm86->regs.ss);
+		vm86regs.pt.ss = seg;
+		get_user_ex(vm86regs.es, &user_vm86->regs.es);
+		get_user_ex(vm86regs.ds, &user_vm86->regs.ds);
+		get_user_ex(vm86regs.fs, &user_vm86->regs.fs);
+		get_user_ex(vm86regs.gs, &user_vm86->regs.gs);
+
+		get_user_ex(vm86->flags, &user_vm86->flags);
+		get_user_ex(vm86->screen_bitmap, &user_vm86->screen_bitmap);
+		get_user_ex(vm86->cpu_type, &user_vm86->cpu_type);
+	} get_user_catch(err);
+	if (err)
+		return err;
+
+	if (copy_from_user(&vm86->int_revectored,
+			   &user_vm86->int_revectored,
+			   sizeof(struct revectored_struct)))
+		return -EFAULT;
+	if (copy_from_user(&vm86->int21_revectored,
+			   &user_vm86->int21_revectored,
+			   sizeof(struct revectored_struct)))
+		return -EFAULT;
+	if (plus) {
+		if (copy_from_user(&vm86->vm86plus, &user_vm86->vm86plus,
+				   sizeof(struct vm86plus_info_struct)))
+			return -EFAULT;
+		vm86->vm86plus.is_vm86pus = 1;
+	} else
+		memset(&vm86->vm86plus, 0,
+		       sizeof(struct vm86plus_info_struct));
+
+	memcpy(&vm86->regs32, regs, sizeof(struct pt_regs));
+	vm86->user_vm86 = user_vm86;
 
 /*
  * The flags register is also special: we cannot trust that the user
  * has set it up safely, so this makes sure interrupt etc flags are
  * inherited from protected mode.
  */
-	VEFLAGS = info->regs.pt.flags;
-	info->regs.pt.flags &= SAFE_MASK;
-	info->regs.pt.flags |= info->regs32->flags & ~SAFE_MASK;
-	info->regs.pt.flags |= X86_VM_MASK;
+	VEFLAGS = vm86regs.pt.flags;
+	vm86regs.pt.flags &= SAFE_MASK;
+	vm86regs.pt.flags |= regs->flags & ~SAFE_MASK;
+	vm86regs.pt.flags |= X86_VM_MASK;
 
-	switch (info->cpu_type) {
+	vm86regs.pt.orig_ax = regs->orig_ax;
+
+	switch (vm86->cpu_type) {
 	case CPU_286:
-		tsk->thread.v86mask = 0;
+		vm86->veflags_mask = 0;
 		break;
 	case CPU_386:
-		tsk->thread.v86mask = X86_EFLAGS_NT | X86_EFLAGS_IOPL;
+		vm86->veflags_mask = X86_EFLAGS_NT | X86_EFLAGS_IOPL;
 		break;
 	case CPU_486:
-		tsk->thread.v86mask = X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL;
+		vm86->veflags_mask = X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL;
 		break;
 	default:
-		tsk->thread.v86mask = X86_EFLAGS_ID | X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL;
+		vm86->veflags_mask = X86_EFLAGS_ID | X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL;
 		break;
 	}
 
 /*
- * Save old state, set default return value (%ax) to 0 (VM86_SIGNAL)
+ * Save old state
  */
-	info->regs32->ax = VM86_SIGNAL;
-	tsk->thread.saved_sp0 = tsk->thread.sp0;
-	tsk->thread.saved_fs = info->regs32->fs;
-	tsk->thread.saved_gs = get_user_gs(info->regs32);
+	vm86->saved_sp0 = tsk->thread.sp0;
+	lazy_save_gs(vm86->regs32.gs);
 
 	tss = &per_cpu(cpu_tss, get_cpu());
-	tsk->thread.sp0 = (unsigned long) &info->VM86_TSS_ESP0;
+	/* make room for real-mode segments */
+	tsk->thread.sp0 += 16;
 	if (cpu_has_sep)
 		tsk->thread.sysenter_cs = 0;
 	load_sp0(tss, &tsk->thread);
 	put_cpu();
 
-	tsk->thread.screen_bitmap = info->screen_bitmap;
-	if (info->flags & VM86_SCREEN_BITMAP)
+	if (vm86->flags & VM86_SCREEN_BITMAP)
 		mark_screen_rdonly(tsk->mm);
 
-	/*call __audit_syscall_exit since we do not exit via the normal paths */
-#ifdef CONFIG_AUDITSYSCALL
-	if (unlikely(current->audit_context))
-		__audit_syscall_exit(1, 0);
-#endif
-
-	__asm__ __volatile__(
-		"movl %0,%%esp\n\t"
-		"movl %1,%%ebp\n\t"
-#ifdef CONFIG_X86_32_LAZY_GS
-		"mov  %2, %%gs\n\t"
-#endif
-		"jmp resume_userspace"
-		: /* no outputs */
-		:"r" (&info->regs), "r" (task_thread_info(tsk)), "r" (0));
-	/* we never return here */
-}
-
-static inline void return_to_32bit(struct kernel_vm86_regs *regs16, int retval)
-{
-	struct pt_regs *regs32;
-
-	regs32 = save_v86_state(regs16);
-	regs32->ax = retval;
-	__asm__ __volatile__("movl %0,%%esp\n\t"
-		"movl %1,%%ebp\n\t"
-		"jmp resume_userspace"
-		: : "r" (regs32), "r" (current_thread_info()));
+	memcpy((struct kernel_vm86_regs *)regs, &vm86regs, sizeof(vm86regs));
+	force_iret();
+	return regs->ax;
 }
 
 static inline void set_IF(struct kernel_vm86_regs *regs)
 {
 	VEFLAGS |= X86_EFLAGS_VIF;
-	if (VEFLAGS & X86_EFLAGS_VIP)
-		return_to_32bit(regs, VM86_STI);
 }
 
 static inline void clear_IF(struct kernel_vm86_regs *regs)
···
 
 static inline void set_vflags_long(unsigned long flags, struct kernel_vm86_regs *regs)
 {
-	set_flags(VEFLAGS, flags, current->thread.v86mask);
+	set_flags(VEFLAGS, flags, current->thread.vm86->veflags_mask);
 	set_flags(regs->pt.flags, flags, SAFE_MASK);
 	if (flags & X86_EFLAGS_IF)
 		set_IF(regs);
···
 
 static inline void set_vflags_short(unsigned short flags, struct kernel_vm86_regs *regs)
 {
-	set_flags(VFLAGS, flags, current->thread.v86mask);
+	set_flags(VFLAGS, flags, current->thread.vm86->veflags_mask);
 	set_flags(regs->pt.flags, flags, SAFE_MASK);
 	if (flags & X86_EFLAGS_IF)
 		set_IF(regs);
···
 	if (VEFLAGS & X86_EFLAGS_VIF)
 		flags |= X86_EFLAGS_IF;
 	flags |= X86_EFLAGS_IOPL;
-	return flags | (VEFLAGS & current->thread.v86mask);
+	return flags | (VEFLAGS & current->thread.vm86->veflags_mask);
 }
 
 static inline int is_revectored(int nr, struct revectored_struct *bitmap)
···
 {
 	unsigned long __user *intr_ptr;
 	unsigned long segoffs;
+	struct vm86 *vm86 = current->thread.vm86;
 
 	if (regs->pt.cs == BIOSSEG)
 		goto cannot_handle;
-	if (is_revectored(i, &KVM86->int_revectored))
+	if (is_revectored(i, &vm86->int_revectored))
 		goto cannot_handle;
-	if (i == 0x21 && is_revectored(AH(regs), &KVM86->int21_revectored))
+	if (i == 0x21 && is_revectored(AH(regs), &vm86->int21_revectored))
 		goto cannot_handle;
 	intr_ptr = (unsigned long __user *) (i << 2);
 	if (get_user(segoffs, intr_ptr))
···
 	return;
 
 cannot_handle:
-	return_to_32bit(regs, VM86_INTx + (i << 8));
+	save_v86_state(regs, VM86_INTx + (i << 8));
 }
 
 int handle_vm86_trap(struct kernel_vm86_regs *regs, long error_code, int trapno)
 {
-	if (VMPI.is_vm86pus) {
+	struct vm86 *vm86 = current->thread.vm86;
+
+	if (vm86->vm86plus.is_vm86pus) {
 		if ((trapno == 3) || (trapno == 1)) {
-			KVM86->regs32->ax = VM86_TRAP + (trapno << 8);
-			/* setting this flag forces the code in entry_32.S to
-			   the path where we call save_v86_state() and change
-			   the stack pointer to KVM86->regs32 */
-			set_thread_flag(TIF_NOTIFY_RESUME);
+			save_v86_state(regs, VM86_TRAP + (trapno << 8));
 			return 0;
 		}
 		do_int(regs, trapno, (unsigned char __user *) (regs->pt.ss << 4), SP(regs));
···
 	unsigned char __user *ssp;
 	unsigned short ip, sp, orig_flags;
 	int data32, pref_done;
+	struct vm86plus_info_struct *vmpi = &current->thread.vm86->vm86plus;
 
 #define CHECK_IF_IN_TRAP \
-	if (VMPI.vm86dbg_active && VMPI.vm86dbg_TFpendig) \
+	if (vmpi->vm86dbg_active && vmpi->vm86dbg_TFpendig) \
 		newflags |= X86_EFLAGS_TF
-#define VM86_FAULT_RETURN do { \
-	if (VMPI.force_return_for_pic  && (VEFLAGS & (X86_EFLAGS_IF | X86_EFLAGS_VIF))) \
-		return_to_32bit(regs, VM86_PICRETURN); \
-	if (orig_flags & X86_EFLAGS_TF) \
-		handle_vm86_trap(regs, 0, 1); \
-	return; } while (0)
 
 	orig_flags = *(unsigned short *)&regs->pt.flags;
 
···
 			SP(regs) -= 2;
 		}
 		IP(regs) = ip;
-		VM86_FAULT_RETURN;
+		goto vm86_fault_return;
 
 	/* popf */
 	case 0x9d:
···
 		else
 			set_vflags_short(newflags, regs);
 
-		VM86_FAULT_RETURN;
+		goto check_vip;
 		}
 
 	/* int xx */
 	case 0xcd: {
 		int intno = popb(csp, ip, simulate_sigsegv);
 		IP(regs) = ip;
-		if (VMPI.vm86dbg_active) {
-			if ((1 << (intno & 7)) & VMPI.vm86dbg_intxxtab[intno >> 3])
-				return_to_32bit(regs, VM86_INTx + (intno << 8));
+		if (vmpi->vm86dbg_active) {
+			if ((1 << (intno & 7)) & vmpi->vm86dbg_intxxtab[intno >> 3]) {
+				save_v86_state(regs, VM86_INTx + (intno << 8));
+				return;
+			}
 		}
 		do_int(regs, intno, ssp, sp);
 		return;
···
 		} else {
 			set_vflags_short(newflags, regs);
 		}
-		VM86_FAULT_RETURN;
+		goto check_vip;
 		}
 
 	/* cli */
 	case 0xfa:
 		IP(regs) = ip;
 		clear_IF(regs);
-		VM86_FAULT_RETURN;
+		goto vm86_fault_return;
 
 	/* sti */
 	/*
···
 	case 0xfb:
 		IP(regs) = ip;
 		set_IF(regs);
-		VM86_FAULT_RETURN;
+		goto check_vip;
 
 	default:
-		return_to_32bit(regs, VM86_UNKNOWN);
+		save_v86_state(regs, VM86_UNKNOWN);
 	}
 
+	return;
+
+check_vip:
+	if (VEFLAGS & X86_EFLAGS_VIP) {
+		save_v86_state(regs, VM86_STI);
+		return;
+	}
+
+vm86_fault_return:
+	if (vmpi->force_return_for_pic  && (VEFLAGS & (X86_EFLAGS_IF | X86_EFLAGS_VIF))) {
+		save_v86_state(regs, VM86_PICRETURN);
+		return;
+	}
+	if (orig_flags & X86_EFLAGS_TF)
+		handle_vm86_trap(regs, 0, X86_TRAP_DB);
 	return;
 
 simulate_sigsegv:
···
 	 *        should be a mixture of the two, but how do we
 	 *        get the information? [KD]
 	 */
-	return_to_32bit(regs, VM86_UNKNOWN);
+	save_v86_state(regs, VM86_UNKNOWN);
 }
 
 /* ---------------- vm86 special IRQ passing stuff ----------------- */

arch/x86/kvm/lapic.c

···
 
 	tsc_deadline = apic->lapic_timer.expired_tscdeadline;
 	apic->lapic_timer.expired_tscdeadline = 0;
-	guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu, native_read_tsc());
+	guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu, rdtsc());
 	trace_kvm_wait_lapic_expire(vcpu->vcpu_id, guest_tsc - tsc_deadline);
 
 	/* __delay is delay_tsc whenever the hardware has TSC, thus always.  */
···
 		local_irq_save(flags);
 
 		now = apic->lapic_timer.timer.base->get_time();
-		guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu, native_read_tsc());
+		guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu, rdtsc());
 		if (likely(tscdeadline > guest_tsc)) {
 			ns = (tscdeadline - guest_tsc) * 1000000ULL;
 			do_div(ns, this_tsc_khz);

arch/x86/kvm/svm.c

···
 {
 	u64 tsc;
 
-	tsc = svm_scale_tsc(vcpu, native_read_tsc());
+	tsc = svm_scale_tsc(vcpu, rdtsc());
 
 	return target_tsc - tsc;
 }
···
 	switch (msr_info->index) {
 	case MSR_IA32_TSC: {
 		msr_info->data = svm->vmcb->control.tsc_offset +
-			svm_scale_tsc(vcpu, native_read_tsc());
+			svm_scale_tsc(vcpu, rdtsc());
 
 		break;
 	}

arch/x86/kvm/vmx.c

···
 {
 	u64 host_tsc, tsc_offset;
 
-	rdtscll(host_tsc);
+	host_tsc = rdtsc();
 	tsc_offset = vmcs_read64(TSC_OFFSET);
 	return host_tsc + tsc_offset;
 }
···
 
 static u64 vmx_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc)
 {
-	return target_tsc - native_read_tsc();
+	return target_tsc - rdtsc();
 }
 
 static bool guest_cpuid_has_vmx(struct kvm_vcpu *vcpu)

arch/x86/kvm/x86.c

···
 
 static cycle_t read_tsc(void)
 {
-	cycle_t ret;
-	u64 last;
-
-	/*
-	 * Empirically, a fence (of type that depends on the CPU)
-	 * before rdtsc is enough to ensure that rdtsc is ordered
-	 * with respect to loads.  The various CPU manuals are unclear
-	 * as to whether rdtsc can be reordered with later loads,
-	 * but no one has ever seen it happen.
-	 */
-	rdtsc_barrier();
-	ret = (cycle_t)vget_cycles();
-
-	last = pvclock_gtod_data.clock.cycle_last;
+	cycle_t ret = (cycle_t)rdtsc_ordered();
+	u64 last = pvclock_gtod_data.clock.cycle_last;
 
 	if (likely(ret >= last))
 		return ret;
···
 		return 1;
 	}
 	if (!use_master_clock) {
-		host_tsc = native_read_tsc();
+		host_tsc = rdtsc();
 		kernel_ns = get_kernel_ns();
 	}
 
···
 
 	if (unlikely(vcpu->cpu != cpu) || check_tsc_unstable()) {
 		s64 tsc_delta = !vcpu->arch.last_host_tsc ? 0 :
-				native_read_tsc() - vcpu->arch.last_host_tsc;
+				rdtsc() - vcpu->arch.last_host_tsc;
 		if (tsc_delta < 0)
 			mark_tsc_unstable("KVM discovered backwards TSC");
 		if (check_tsc_unstable()) {
···
 {
 	kvm_x86_ops->vcpu_put(vcpu);
 	kvm_put_guest_fpu(vcpu);
-	vcpu->arch.last_host_tsc = native_read_tsc();
+	vcpu->arch.last_host_tsc = rdtsc();
 }
 
 static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
···
 		hw_breakpoint_restore();
 
 	vcpu->arch.last_guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu,
-							   native_read_tsc());
+							   rdtsc());
 
 	vcpu->mode = OUTSIDE_GUEST_MODE;
 	smp_wmb();
···
 	if (ret != 0)
 		return ret;
 
-	local_tsc = native_read_tsc();
+	local_tsc = rdtsc();
 	stable = !check_tsc_unstable();
 	list_for_each_entry(kvm, &vm_list, vm_list) {
 		kvm_for_each_vcpu(i, vcpu, kvm) {

arch/x86/lib/delay.c

···
 /* TSC based delay: */
 static void delay_tsc(unsigned long __loops)
 {
-	u32 bclock, now, loops = __loops;
+	u64 bclock, now, loops = __loops;
 	int cpu;
 
 	preempt_disable();
 	cpu = smp_processor_id();
-	rdtsc_barrier();
-	rdtscl(bclock);
+	bclock = rdtsc_ordered();
 	for (;;) {
-		rdtsc_barrier();
-		rdtscl(now);
+		now = rdtsc_ordered();
 		if ((now - bclock) >= loops)
 			break;
 
···
 		if (unlikely(cpu != smp_processor_id())) {
 			loops -= (now - bclock);
 			cpu = smp_processor_id();
-			rdtsc_barrier();
-			rdtscl(bclock);
+			bclock = rdtsc_ordered();
 		}
 	}
 	preempt_enable();
···
 int read_current_timer(unsigned long *timer_val)
 {
 	if (delay_fn == delay_tsc) {
-		rdtscll(*timer_val);
+		*timer_val = rdtsc();
 		return 0;
 	}
 	return -1;

arch/x86/math-emu/get_address.c

···
 
 #include <asm/uaccess.h>
 #include <asm/desc.h>
+#include <asm/vm86.h>
 
 #include "fpu_system.h"
 #include "exception.h"

arch/x86/mm/fault.c

···
 #include <asm/kmemcheck.h>		/* kmemcheck_*(), ...		*/
 #include <asm/fixmap.h>			/* VSYSCALL_ADDR		*/
 #include <asm/vsyscall.h>		/* emulate_vsyscall		*/
+#include <asm/vm86.h>			/* struct vm86			*/
 
 #define CREATE_TRACE_POINTS
 #include <asm/trace/exceptions.h>
···
 check_v8086_mode(struct pt_regs *regs, unsigned long address,
 		 struct task_struct *tsk)
 {
+#ifdef CONFIG_VM86
 	unsigned long bit;
 
-	if (!v8086_mode(regs))
+	if (!v8086_mode(regs) || !tsk->thread.vm86)
 		return;
 
 	bit = (address - 0xA0000) >> PAGE_SHIFT;
 	if (bit < 32)
-		tsk->thread.screen_bitmap |= 1 << bit;
+		tsk->thread.vm86->screen_bitmap |= 1 << bit;
+#endif
 }
 
 static bool low_pfn(unsigned long pfn)

arch/x86/um/asm/barrier.h

···
 #define read_barrier_depends()		do { } while (0)
 #define smp_read_barrier_depends()	do { } while (0)
 
-/*
- * Stop RDTSC speculation. This is needed when you need to use RDTSC
- * (or get_cycles or vread that possibly accesses the TSC) in a defined
- * code region.
- *
- * (Could use an alternative three way for this if there was one.)
- */
-static inline void rdtsc_barrier(void)
-{
-	alternative_2("", "mfence", X86_FEATURE_MFENCE_RDTSC,
-			  "lfence", X86_FEATURE_LFENCE_RDTSC);
-}
-
 #endif

arch/x86/xen/enlighten.c

···
 	.read_msr = xen_read_msr_safe,
 	.write_msr = xen_write_msr_safe,
 
-	.read_tsc = native_read_tsc,
 	.read_pmc = native_read_pmc,
-
-	.read_tscp = native_read_tscp,
 
 	.iret = xen_iret,
 #ifdef CONFIG_X86_64

drivers/cpufreq/intel_pstate.c

···
 	local_irq_save(flags);
 	rdmsrl(MSR_IA32_APERF, aperf);
 	rdmsrl(MSR_IA32_MPERF, mperf);
-	tsc = native_read_tsc();
+	tsc = rdtsc();
 	local_irq_restore(flags);
 
 	cpu->last_sample_time = cpu->sample.time;

drivers/input/gameport/gameport.c

···
 
 	for(i = 0; i < 50; i++) {
 		local_irq_save(flags);
-		rdtscl(t1);
+		t1 = rdtsc();
 		for (t = 0; t < 50; t++) gameport_read(gameport);
-		rdtscl(t2);
+		t2 = rdtsc();
 		local_irq_restore(flags);
 		udelay(i * 10);
 		if (t2 - t1 < tx) tx = t2 - t1;

drivers/input/joystick/analog.c

···
 
 #include <linux/i8253.h>
 
-#define GET_TIME(x)	do { if (cpu_has_tsc) rdtscl(x); else x = get_time_pit(); } while (0)
+#define GET_TIME(x)	do { if (cpu_has_tsc) x = (unsigned int)rdtsc(); else x = get_time_pit(); } while (0)
 #define DELTA(x,y)	(cpu_has_tsc ? ((y) - (x)) : ((x) - (y) + ((x) < (y) ? PIT_TICK_RATE / HZ : 0)))
 #define TIME_NAME	(cpu_has_tsc?"TSC":"PIT")
 static unsigned int get_time_pit(void)
···
         return count;
 }
 #elif defined(__x86_64__)
-#define GET_TIME(x)	rdtscl(x)
+#define GET_TIME(x)	do { x = (unsigned int)rdtsc(); } while (0)
 #define DELTA(x,y)	((y)-(x))
 #define TIME_NAME	"TSC"
 #elif defined(__alpha__) || defined(CONFIG_MN10300) || defined(CONFIG_ARM) || defined(CONFIG_ARM64) || defined(CONFIG_TILE)

drivers/net/hamradio/baycom_epp.c

···
 #define GETTICK(x)                                                \
 ({                                                                \
 	if (cpu_has_tsc)                                          \
-		rdtscl(x);                                        \
+		x = (unsigned int)rdtsc();		  \
 })
 #else /* __i386__ */
 #define GETTICK(x)

drivers/scsi/dpt_i2o.c

···
 #endif
 
 #if defined __i386__
+
+#include <uapi/asm/vm86.h>
+
 static void adpt_i386_info(sysInfo_S* si)
 {
 	// This is all the info we need for now

drivers/staging/media/lirc/lirc_serial.c

···
  * time
  */
 
-/* So send_pulse can quickly convert microseconds to clocks */
-static unsigned long conv_us_to_clocks;
-
 static int init_timing_params(unsigned int new_duty_cycle,
 		unsigned int new_freq)
 {
···
 	/* How many clocks in a microsecond?, avoiding long long divide */
 	work = loops_per_sec;
 	work *= 4295;  /* 4295 = 2^32 / 1e6 */
-	conv_us_to_clocks = work >> 32;
 
 	/*
 	 * Carrier period in clocks, approach good up to 32GHz clock,
···
 	pulse_width = period * duty_cycle / 100;
 	space_width = period - pulse_width;
 	dprintk("in init_timing_params, freq=%d, duty_cycle=%d, "
-		"clk/jiffy=%ld, pulse=%ld, space=%ld, "
-		"conv_us_to_clocks=%ld\n",
+		"clk/jiffy=%ld, pulse=%ld, space=%ld\n",
 		freq, duty_cycle, __this_cpu_read(cpu_info.loops_per_jiffy),
-		pulse_width, space_width, conv_us_to_clocks);
+		pulse_width, space_width);
 	return 0;
 }
 #else /* ! USE_RDTSC */
···
 	return ret;
 }
 
-#ifdef USE_RDTSC
-/* Version that uses Pentium rdtsc instruction to measure clocks */
-
-/*
- * This version does sub-microsecond timing using rdtsc instruction,
- * and does away with the fudged LIRC_SERIAL_TRANSMITTER_LATENCY
- * Implicitly i586 architecture...  - Steve
- */
-
-static long send_pulse_homebrew_softcarrier(unsigned long length)
-{
-	int flag;
-	unsigned long target, start, now;
-
-	/* Get going quick as we can */
-	rdtscl(start);
-	on();
-	/* Convert length from microseconds to clocks */
-	length *= conv_us_to_clocks;
-	/* And loop till time is up - flipping at right intervals */
-	now = start;
-	target = pulse_width;
-	flag = 1;
-	/*
-	 * FIXME: This looks like a hard busy wait, without even an occasional,
-	 * polite, cpu_relax() call.  There's got to be a better way?
-	 *
-	 * The i2c code has the result of a lot of bit-banging work, I wonder if
-	 * there's something there which could be helpful here.
-	 */
-	while ((now - start) < length) {
-		/* Delay till flip time */
-		do {
-			rdtscl(now);
-		} while ((now - start) < target);
-
-		/* flip */
-		if (flag) {
-			rdtscl(now);
-			off();
-			target += space_width;
-		} else {
-			rdtscl(now); on();
-			target += pulse_width;
-		}
-		flag = !flag;
-	}
-	rdtscl(now);
-	return ((now - start) - length) / conv_us_to_clocks;
-}
-#else /* ! USE_RDTSC */
 /* Version using udelay() */
 
 /*
  * here we use fixed point arithmetic, with 8
  * fractional bits.  that gets us within 0.1% or so of the right average
  * frequency, albeit with some jitter in pulse length - Steve
+ *
+ * This should use ndelay instead.
  */
 
 /* To match 8 fractional bits used for pulse/space length */
···
 	}
 	return (actual-length) >> 8;
 }
-#endif /* USE_RDTSC */
 
 static long send_pulse_homebrew(unsigned long length)
 {

drivers/thermal/intel_powerclamp.c

···
 
 	/* check result for the last window */
 	msr_now = pkg_state_counter();
-	rdtscll(tsc_now);
+	tsc_now = rdtsc();
 
 	/* calculate pkg cstate vs tsc ratio */
 	if (!msr_last || !tsc_last)
···
 	u64 val64;
 
 	msr_now = pkg_state_counter();
-	rdtscll(tsc_now);
+	tsc_now = rdtsc();
 	jiffies_now = jiffies;
 
 	/* calculate pkg cstate vs tsc ratio */

include/linux/context_tracking.h

···
 	}
 }
 
+
+/**
+ * ct_state() - return the current context tracking state if known
+ *
+ * Returns the current cpu's context tracking state if context tracking
+ * is enabled.  If context tracking is disabled, returns
+ * CONTEXT_DISABLED.  This should be used primarily for debugging.
+ */
+static inline enum ctx_state ct_state(void)
+{
+	return context_tracking_is_enabled() ?
+		this_cpu_read(context_tracking.state) : CONTEXT_DISABLED;
+}
 #else
 static inline void user_enter(void) { }
 static inline void user_exit(void) { }
 static inline enum ctx_state exception_enter(void) { return 0; }
 static inline void exception_exit(enum ctx_state prev_ctx) { }
+static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }
 #endif /* !CONFIG_CONTEXT_TRACKING */
 
+#define CT_WARN_ON(cond) WARN_ON(context_tracking_is_enabled() && (cond))
 
 #ifdef CONFIG_CONTEXT_TRACKING_FORCE
 extern void context_tracking_init(void);

include/linux/context_tracking_state.h

···
 	bool active;
 	int recursion;
 	enum ctx_state {
+		CONTEXT_DISABLED = -1,	/* returned by ct_state() if unknown */
 		CONTEXT_KERNEL = 0,
 		CONTEXT_USER,
 		CONTEXT_GUEST,

include/linux/spinlock.h

···
  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
  */
 
-static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
+static __always_inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
 {
 	return &lock->rlock;
 }
···
 	raw_spin_lock_init(&(_lock)->rlock);		\
 } while (0)
 
-static inline void spin_lock(spinlock_t *lock)
+static __always_inline void spin_lock(spinlock_t *lock)
 {
 	raw_spin_lock(&lock->rlock);
 }
 
-static inline void spin_lock_bh(spinlock_t *lock)
+static __always_inline void spin_lock_bh(spinlock_t *lock)
 {
 	raw_spin_lock_bh(&lock->rlock);
 }
 
-static inline int spin_trylock(spinlock_t *lock)
+static __always_inline int spin_trylock(spinlock_t *lock)
 {
 	return raw_spin_trylock(&lock->rlock);
 }
···
 	raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock);	\
 } while (0)
 
-static inline void spin_lock_irq(spinlock_t *lock)
+static __always_inline void spin_lock_irq(spinlock_t *lock)
 {
 	raw_spin_lock_irq(&lock->rlock);
 }
···
 	raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
 } while (0)
 
-static inline void spin_unlock(spinlock_t *lock)
+static __always_inline void spin_unlock(spinlock_t *lock)
 {
 	raw_spin_unlock(&lock->rlock);
 }
 
-static inline void spin_unlock_bh(spinlock_t *lock)
+static __always_inline void spin_unlock_bh(spinlock_t *lock)
 {
 	raw_spin_unlock_bh(&lock->rlock);
 }
 
-static inline void spin_unlock_irq(spinlock_t *lock)
+static __always_inline void spin_unlock_irq(spinlock_t *lock)
 {
 	raw_spin_unlock_irq(&lock->rlock);
 }
 
-static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
+static __always_inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 {
 	raw_spin_unlock_irqrestore(&lock->rlock, flags);
 }
 
-static inline int spin_trylock_bh(spinlock_t *lock)
+static __always_inline int spin_trylock_bh(spinlock_t *lock)
 {
 	return raw_spin_trylock_bh(&lock->rlock);
 }
 
-static inline int spin_trylock_irq(spinlock_t *lock)
+static __always_inline int spin_trylock_irq(spinlock_t *lock)
 {
 	return raw_spin_trylock_irq(&lock->rlock);
 }
···
 	raw_spin_trylock_irqsave(spinlock_check(lock), flags); \
 })
 
-static inline void spin_unlock_wait(spinlock_t *lock)
+static __always_inline void spin_unlock_wait(spinlock_t *lock)
 {
 	raw_spin_unlock_wait(&lock->rlock);
 }
 
-static inline int spin_is_locked(spinlock_t *lock)
+static __always_inline int spin_is_locked(spinlock_t *lock)
 {
 	return raw_spin_is_locked(&lock->rlock);
 }
 
-static inline int spin_is_contended(spinlock_t *lock)
+static __always_inline int spin_is_contended(spinlock_t *lock)
 {
 	return raw_spin_is_contended(&lock->rlock);
 }
 
-static inline int spin_can_lock(spinlock_t *lock)
+static __always_inline int spin_can_lock(spinlock_t *lock)
 {
 	return raw_spin_can_lock(&lock->rlock);
 }

kernel/notifier.c

···
 		.signr	= sig,
 
 	};
+	rcu_lockdep_assert(rcu_is_watching(),
+			   "notify_die called but RCU thinks we're quiescent");
 	return atomic_notifier_call_chain(&die_chain, val, &args);
 }
 NOKPROBE_SYMBOL(notify_die);

kernel/sys_ni.c

···
 cond_syscall(sys_ssetmask);
 cond_syscall(sys_vm86old);
 cond_syscall(sys_vm86);
+cond_syscall(sys_modify_ldt);
 cond_syscall(sys_ipc);
 cond_syscall(compat_sys_ipc);
 cond_syscall(compat_sys_sysctl);

tools/power/cpupower/debug/kernel/cpufreq-test_tsc.c

···
 
 	printk(KERN_DEBUG "start--> \n");
 	then = read_pmtmr();
-        rdtscll(then_tsc);
+	then_tsc = rdtsc();
 	for (i=0;i<20;i++) {
 		mdelay(100);
 		now = read_pmtmr();
-		rdtscll(now_tsc);
+		now_tsc = rdtsc();
 		diff = (now - then) & 0xFFFFFF;
 		diff_tsc = now_tsc - then_tsc;
 		printk(KERN_DEBUG "t1: %08u t2: %08u diff_pmtmr: %08u diff_tsc: %016llu\n", then, now, diff, diff_tsc);

tools/testing/selftests/x86/Makefile

···
 
 .PHONY: all all_32 all_64 warn_32bit_failure clean
 
-TARGETS_C_BOTHBITS := sigreturn single_step_syscall sysret_ss_attrs
-TARGETS_C_32BIT_ONLY := entry_from_vm86
+TARGETS_C_BOTHBITS := sigreturn single_step_syscall sysret_ss_attrs ldt_gdt
+TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault
 
 TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY)
 BINARIES_32 := $(TARGETS_C_32BIT_ALL:%=%_32)

tools/testing/selftests/x86/entry_from_vm86.c

···
 static unsigned long load_addr = 0x10000;
 static int nerrs = 0;
 
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+		       int flags)
+{
+	struct sigaction sa;
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_sigaction = handler;
+	sa.sa_flags = SA_SIGINFO | flags;
+	sigemptyset(&sa.sa_mask);
+	if (sigaction(sig, &sa, 0))
+		err(1, "sigaction");
+}
+
+static void clearhandler(int sig)
+{
+	struct sigaction sa;
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = SIG_DFL;
+	sigemptyset(&sa.sa_mask);
+	if (sigaction(sig, &sa, 0))
+		err(1, "sigaction");
+}
+
+static sig_atomic_t got_signal;
+
+static void sighandler(int sig, siginfo_t *info, void *ctx_void)
+{
+	ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+	if (ctx->uc_mcontext.gregs[REG_EFL] & X86_EFLAGS_VM ||
+	    (ctx->uc_mcontext.gregs[REG_CS] & 3) != 3) {
+		printf("[FAIL]\tSignal frame should not reflect vm86 mode\n");
+		nerrs++;
+	}
+
+	const char *signame;
+	if (sig == SIGSEGV)
+		signame = "SIGSEGV";
+	else if (sig == SIGILL)
+		signame = "SIGILL";
+	else
+		signame = "unexpected signal";
+
+	printf("[INFO]\t%s: FLAGS = 0x%lx, CS = 0x%hx\n", signame,
+	       (unsigned long)ctx->uc_mcontext.gregs[REG_EFL],
+	       (unsigned short)ctx->uc_mcontext.gregs[REG_CS]);
+
+	got_signal = 1;
+}
+
 asm (
 	".pushsection .rodata\n\t"
 	".type vmcode_bound, @object\n\t"
···
 	"int3\n\t"
 	"vmcode_sysenter:\n\t"
 	"sysenter\n\t"
+	"vmcode_syscall:\n\t"
+	"syscall\n\t"
+	"vmcode_sti:\n\t"
+	"sti\n\t"
+	"vmcode_int3:\n\t"
+	"int3\n\t"
+	"vmcode_int80:\n\t"
+	"int $0x80\n\t"
 	".size vmcode, . - vmcode\n\t"
 	"end_vmcode:\n\t"
 	".code32\n\t"
···
 	);
 
 extern unsigned char vmcode[], end_vmcode[];
-extern unsigned char vmcode_bound[], vmcode_sysenter[];
+extern unsigned char vmcode_bound[], vmcode_sysenter[], vmcode_syscall[],
+	vmcode_sti[], vmcode_int3[], vmcode_int80[];
 
-static void do_test(struct vm86plus_struct *v86, unsigned long eip,
+/* Returns false if the test was skipped. */
+static bool do_test(struct vm86plus_struct *v86, unsigned long eip,
+		    unsigned int rettype, unsigned int retarg,
 		    const char *text)
 {
 	long ret;
···
 
 	if (ret == -1 && errno == ENOSYS) {
 		printf("[SKIP]\tvm86 not supported\n");
-		return;
+		return false;
 	}
 
 	if (VM86_TYPE(ret) == VM86_INTx) {
···
 		else
 			sprintf(trapname, "%d", trapno);
 
-		printf("[OK]\tExited vm86 mode due to #%s\n", trapname);
+		printf("[INFO]\tExited vm86 mode due to #%s\n", trapname);
 	} else if (VM86_TYPE(ret) == VM86_UNKNOWN) {
-		printf("[OK]\tExited vm86 mode due to unhandled GP fault\n");
+		printf("[INFO]\tExited vm86 mode due to unhandled GP fault\n");
+	} else if (VM86_TYPE(ret) == VM86_TRAP) {
+		printf("[INFO]\tExited vm86 mode due to a trap (arg=%ld)\n",
+		       VM86_ARG(ret));
+	} else if (VM86_TYPE(ret) == VM86_SIGNAL) {
+		printf("[INFO]\tExited vm86 mode due to a signal\n");
+	} else if (VM86_TYPE(ret) == VM86_STI) {
+		printf("[INFO]\tExited vm86 mode due to STI\n");
 	} else {
-		printf("[OK]\tExited vm86 mode due to type %ld, arg %ld\n",
+		printf("[INFO]\tExited vm86 mode due to type %ld, arg %ld\n",
 		       VM86_TYPE(ret), VM86_ARG(ret));
 	}
+
+	if (rettype == -1 ||
+	    (VM86_TYPE(ret) == rettype && VM86_ARG(ret) == retarg)) {
+		printf("[OK]\tReturned correctly\n");
+	} else {
+		printf("[FAIL]\tIncorrect return reason\n");
+		nerrs++;
+	}
+
+	return true;
 }
 
 int main(void)
···
 	assert((v86.regs.cs & 3) == 0);	/* Looks like RPL = 0 */
 
 	/* #BR -- should deliver SIG??? */
-	do_test(&v86, vmcode_bound - vmcode, "#BR");
+	do_test(&v86, vmcode_bound - vmcode, VM86_INTx, 5, "#BR");
 
-	/* SYSENTER -- should cause #GP or #UD depending on CPU */
-	do_test(&v86, vmcode_sysenter - vmcode, "SYSENTER");
+	/*
+	 * SYSENTER -- should cause #GP or #UD depending on CPU.
+	 * Expected return type -1 means that we shouldn't validate
+	 * the vm86 return value.  This will avoid problems on non-SEP
+	 * CPUs.
+	 */
+	sethandler(SIGILL, sighandler, 0);
+	do_test(&v86, vmcode_sysenter - vmcode, -1, 0, "SYSENTER");
+	clearhandler(SIGILL);
+
+	/*
+	 * SYSCALL would be a disaster in VM86 mode.  Fortunately,
+	 * there is no kernel that both enables SYSCALL and sets
+	 * EFER.SCE, so it's #UD on all systems.  But vm86 is
+	 * buggy (or has a "feature"), so the SIGILL will actually
+	 * be delivered.
+	 */
+	sethandler(SIGILL, sighandler, 0);
+	do_test(&v86, vmcode_syscall - vmcode, VM86_SIGNAL, 0, "SYSCALL");
+	clearhandler(SIGILL);
+
+	/* STI with VIP set */
+	v86.regs.eflags |= X86_EFLAGS_VIP;
+	v86.regs.eflags &= ~X86_EFLAGS_IF;
+	do_test(&v86, vmcode_sti - vmcode, VM86_STI, 0, "STI with VIP set");
+
+	/* INT3 -- should cause #BP */
+	do_test(&v86, vmcode_int3 - vmcode, VM86_TRAP, 3, "INT3");
+
+	/* INT80 -- should exit with "INTx 0x80" */
+	v86.regs.eax = (unsigned int)-1;
+	do_test(&v86, vmcode_int80 - vmcode, VM86_INTx, 0x80, "int80");
+
+	/* Execute a null pointer */
+	v86.regs.cs = 0;
+	v86.regs.ss = 0;
+	sethandler(SIGSEGV, sighandler, 0);
+	got_signal = 0;
+	if (do_test(&v86, 0, VM86_SIGNAL, 0, "Execute null pointer") &&
+	    !got_signal) {
+		printf("[FAIL]\tDid not receive SIGSEGV\n");
+		nerrs++;
+	}
+	clearhandler(SIGSEGV);
 
 	return (nerrs == 0 ? 0 : 1);
 }

tools/testing/selftests/x86/ldt_gdt.c

···
+/*
+ * ldt_gdt.c - Test cases for LDT and GDT access
+ * Copyright (c) 2015 Andrew Lutomirski
+ */
+
+#define _GNU_SOURCE
+#include <err.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <signal.h>
+#include <setjmp.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <asm/ldt.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdbool.h>
+#include <pthread.h>
+#include <sched.h>
+#include <linux/futex.h>
+
+#define AR_ACCESSED		(1<<8)
+
+#define AR_TYPE_RODATA		(0 * (1<<9))
+#define AR_TYPE_RWDATA		(1 * (1<<9))
+#define AR_TYPE_RODATA_EXPDOWN	(2 * (1<<9))
+#define AR_TYPE_RWDATA_EXPDOWN	(3 * (1<<9))
+#define AR_TYPE_XOCODE		(4 * (1<<9))
+#define AR_TYPE_XRCODE		(5 * (1<<9))
+#define AR_TYPE_XOCODE_CONF	(6 * (1<<9))
+#define AR_TYPE_XRCODE_CONF	(7 * (1<<9))
+
+#define AR_DPL3			(3 * (1<<13))
+
+#define AR_S			(1 << 12)
+#define AR_P			(1 << 15)
+#define AR_AVL			(1 << 20)
+#define AR_L			(1 << 21)
+#define AR_DB			(1 << 22)
+#define AR_G			(1 << 23)
+
+static int nerrs;
+
+static void check_invalid_segment(uint16_t index, int ldt)
+{
+	uint32_t has_limit = 0, has_ar = 0, limit, ar;
+	uint32_t selector = (index << 3) | (ldt << 2) | 3;
+
+	asm ("lsl %[selector], %[limit]\n\t"
+	     "jnz 1f\n\t"
+	     "movl $1, %[has_limit]\n\t"
+	     "1:"
+	     : [limit] "=r" (limit), [has_limit] "+rm" (has_limit)
+	     : [selector] "r" (selector));
+	asm ("larl %[selector], %[ar]\n\t"
+	     "jnz 1f\n\t"
+	     "movl $1, %[has_ar]\n\t"
+	     "1:"
+	     : [ar] "=r" (ar), [has_ar] "+rm" (has_ar)
+	     : [selector] "r" (selector));
+
+	if (has_limit || has_ar) {
+		printf("[FAIL]\t%s entry %hu is valid but should be invalid\n",
+		       (ldt ? "LDT" : "GDT"), index);
+		nerrs++;
+	} else {
+		printf("[OK]\t%s entry %hu is invalid\n",
+		       (ldt ? "LDT" : "GDT"), index);
+	}
+}
+
+static void check_valid_segment(uint16_t index, int ldt,
+				uint32_t expected_ar, uint32_t expected_limit,
+				bool verbose)
+{
+	uint32_t has_limit = 0, has_ar = 0, limit, ar;
+	uint32_t selector = (index << 3) | (ldt << 2) | 3;
+
+	asm ("lsl %[selector], %[limit]\n\t"
+	     "jnz 1f\n\t"
+	     "movl $1, %[has_limit]\n\t"
+	     "1:"
+	     : [limit] "=r" (limit), [has_limit] "+rm" (has_limit)
+	     : [selector] "r" (selector));
+	asm ("larl %[selector], %[ar]\n\t"
+	     "jnz 1f\n\t"
+	     "movl $1, %[has_ar]\n\t"
+	     "1:"
+	     : [ar] "=r" (ar), [has_ar] "+rm" (has_ar)
+	     : [selector] "r" (selector));
+
+	if (!has_limit || !has_ar) {
+		printf("[FAIL]\t%s entry %hu is invalid but should be valid\n",
+		       (ldt ? "LDT" : "GDT"), index);
+		nerrs++;
+		return;
+	}
+
+	if (ar != expected_ar) {
+		printf("[FAIL]\t%s entry %hu has AR 0x%08X but expected 0x%08X\n",
+		       (ldt ? "LDT" : "GDT"), index, ar, expected_ar);
+		nerrs++;
+	} else if (limit != expected_limit) {
+		printf("[FAIL]\t%s entry %hu has limit 0x%08X but expected 0x%08X\n",
+		       (ldt ? "LDT" : "GDT"), index, limit, expected_limit);
+		nerrs++;
+	} else if (verbose) {
+		printf("[OK]\t%s entry %hu has AR 0x%08X and limit 0x%08X\n",
+		       (ldt ? "LDT" : "GDT"), index, ar, limit);
+	}
+}
+
+static bool install_valid_mode(const struct user_desc *desc, uint32_t ar,
+			       bool oldmode)
+{
+	int ret = syscall(SYS_modify_ldt, oldmode ? 1 : 0x11,
+			  desc, sizeof(*desc));
+	if (ret < -1)
+		errno = -ret;
+	if (ret == 0) {
+		uint32_t limit = desc->limit;
+		if (desc->limit_in_pages)
+			limit = (limit << 12) + 4095;
+		check_valid_segment(desc->entry_number, 1, ar, limit, true);
+		return true;
+	} else if (errno == ENOSYS) {
+		printf("[OK]\tmodify_ldt returned -ENOSYS\n");
+		return false;
+	} else {
+		if (desc->seg_32bit) {
+			printf("[FAIL]\tUnexpected modify_ldt failure %d\n",
+			       errno);
+			nerrs++;
+			return false;
+		} else {
+			printf("[OK]\tmodify_ldt rejected 16 bit segment\n");
+			return false;
+		}
+	}
+}
+
+static bool install_valid(const struct user_desc *desc, uint32_t ar)
+{
+	return install_valid_mode(desc, ar, false);
+}
+
+static void install_invalid(const struct user_desc *desc, bool oldmode)
+{
+	int ret = syscall(SYS_modify_ldt, oldmode ? 1 : 0x11,
+			  desc, sizeof(*desc));
+	if (ret < -1)
+		errno = -ret;
+	if (ret == 0) {
+		check_invalid_segment(desc->entry_number, 1);
+	} else if (errno == ENOSYS) {
+		printf("[OK]\tmodify_ldt returned -ENOSYS\n");
+	} else {
+		if (desc->seg_32bit) {
+			printf("[FAIL]\tUnexpected modify_ldt failure %d\n",
+			       errno);
+			nerrs++;
+		} else {
+			printf("[OK]\tmodify_ldt rejected 16 bit segment\n");
+		}
+	}
+}
+
+static int safe_modify_ldt(int func, struct user_desc *ptr,
+			   unsigned long bytecount)
+{
+	int ret = syscall(SYS_modify_ldt, 0x11, ptr, bytecount);
+	if (ret < -1)
+		errno = -ret;
+	return ret;
+}
+
+static void fail_install(struct user_desc *desc)
+{
+	if (safe_modify_ldt(0x11, desc, sizeof(*desc)) == 0) {
+		printf("[FAIL]\tmodify_ldt accepted a bad descriptor\n");
+		nerrs++;
+	} else if (errno == ENOSYS) {
+		printf("[OK]\tmodify_ldt returned -ENOSYS\n");
+	} else {
+		printf("[OK]\tmodify_ldt failure %d\n", errno);
+	}
+}
+
+static void do_simple_tests(void)
+{
+	struct user_desc desc = {
+		.entry_number    = 0,
+		.base_addr       = 0,
+		.limit           = 10,
+		.seg_32bit       = 1,
+		.contents        = 2, /* Code, not conforming */
+		.read_exec_only  = 0,
+		.limit_in_pages  = 0,
+		.seg_not_present = 0,
+		.useable         = 0
+	};
+	install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | AR_S | AR_P | AR_DB);
+
+	desc.limit_in_pages = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+		      AR_S | AR_P | AR_DB | AR_G);
+
+	check_invalid_segment(1, 1);
+
+	desc.entry_number = 2;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+		      AR_S | AR_P | AR_DB | AR_G);
+
+	check_invalid_segment(1, 1);
+
+	desc.base_addr = 0xf0000000;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+		      AR_S | AR_P | AR_DB | AR_G);
+
+	desc.useable = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+		      AR_S | AR_P | AR_DB | AR_G | AR_AVL);
+
+	desc.seg_not_present = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+		      AR_S | AR_DB | AR_G | AR_AVL);
+
+	desc.seg_32bit = 0;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+		      AR_S | AR_G | AR_AVL);
+
+	desc.seg_32bit = 1;
+	desc.contents = 0;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA |
+		      AR_S | AR_DB | AR_G | AR_AVL);
+
+	desc.read_exec_only = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA |
+		      AR_S | AR_DB | AR_G | AR_AVL);
+
+	desc.contents = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA_EXPDOWN |
+		      AR_S | AR_DB | AR_G | AR_AVL);
+
+	desc.read_exec_only = 0;
+	desc.limit_in_pages = 0;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA_EXPDOWN |
+		      AR_S | AR_DB | AR_AVL);
+
+	desc.contents = 3;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE_CONF |
+		      AR_S | AR_DB | AR_AVL);
+
+	desc.read_exec_only = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_XOCODE_CONF |
+		      AR_S | AR_DB | AR_AVL);
+
+	desc.read_exec_only = 0;
+	desc.contents = 2;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE |
+		      AR_S | AR_DB | AR_AVL);
+
+	desc.read_exec_only = 1;
+
+#ifdef __x86_64__
+	desc.lm = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_XOCODE |
+		      AR_S | AR_DB | AR_AVL);
+	desc.lm = 0;
+#endif
+
+	bool entry1_okay = install_valid(&desc, AR_DPL3 | AR_TYPE_XOCODE |
+					 AR_S | AR_DB | AR_AVL);
+
+	if (entry1_okay) {
+		printf("[RUN]\tTest fork\n");
+		pid_t child = fork();
+		if (child == 0) {
+			nerrs = 0;
+			check_valid_segment(desc.entry_number, 1,
+					    AR_DPL3 | AR_TYPE_XOCODE |
+					    AR_S | AR_DB | AR_AVL, desc.limit,
+					    true);
+			check_invalid_segment(1, 1);
+			exit(nerrs ? 1 : 0);
+		} else {
+			int status;
+			if (waitpid(child, &status, 0) != child ||
+			    !WIFEXITED(status)) {
+				printf("[FAIL]\tChild died\n");
+				nerrs++;
+			} else if (WEXITSTATUS(status) != 0) {
+				printf("[FAIL]\tChild failed\n");
+				nerrs++;
+			} else {
+				printf("[OK]\tChild succeeded\n");
+			}
+		}
+
+		printf("[RUN]\tTest size\n");
+		int i;
+		for (i = 0; i < 8192; i++) {
+			desc.entry_number = i;
+			desc.limit = i;
+			if (safe_modify_ldt(0x11, &desc, sizeof(desc)) != 0) {
+				printf("[FAIL]\tFailed to install entry %d\n", i);
+				nerrs++;
+				break;
+			}
+		}
+		for (int j = 0; j < i; j++) {
+			check_valid_segment(j, 1, AR_DPL3 | AR_TYPE_XOCODE |
+					    AR_S | AR_DB | AR_AVL, j, false);
+		}
+		printf("[DONE]\tSize test\n");
+	} else {
+		printf("[SKIP]\tSkipping fork and size tests because we have no LDT\n");
+	}
+
+	/* Test entry_number too high. */
+	desc.entry_number = 8192;
+	fail_install(&desc);
+
+	/* Test deletion and actions mistakeable for deletion. */
+	memset(&desc, 0, sizeof(desc));
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P);
+
+	desc.seg_not_present = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S);
+
+	desc.seg_not_present = 0;
+	desc.read_exec_only = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S | AR_P);
+
+	desc.read_exec_only = 0;
+	desc.seg_not_present = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S);
+
+	desc.read_exec_only = 1;
+	desc.limit = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S);
+
+	desc.limit = 0;
+	desc.base_addr = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S);
+
+	desc.base_addr = 0;
+	install_invalid(&desc, false);
+
+	desc.seg_not_present = 0;
+	desc.read_exec_only = 0;
+	desc.seg_32bit = 1;
+	install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P | AR_DB);
+	install_invalid(&desc, true);
+}
+
+/*
+ * 0: thread is idle
+ * 1: thread armed
+ * 2: thread should clear LDT entry 0
+ * 3: thread should exit
+ */
+static volatile unsigned int ftx;
+
+static void *threadproc(void *ctx)
+{
+	cpu_set_t cpuset;
+	CPU_ZERO(&cpuset);
+	CPU_SET(1, &cpuset);
+	if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
+		err(1, "sched_setaffinity to CPU 1");	/* should never fail */
+
+	while (1) {
+		syscall(SYS_futex, &ftx, FUTEX_WAIT, 0, NULL, NULL, 0);
+		while (ftx != 2) {
+			if (ftx >= 3)
+				return NULL;
+		}
+
+		/* clear LDT entry 0 */
+		const struct user_desc desc = {};
+		if (syscall(SYS_modify_ldt, 1, &desc, sizeof(desc)) != 0)
+			err(1, "modify_ldt");
+
+		/* If ftx == 2, set it to zero.  If ftx == 100, quit. */
+		unsigned int x = -2;
+		asm volatile ("lock xaddl %[x], %[ftx]" :
+			      [x] "+r" (x), [ftx] "+m" (ftx));
+		if (x != 2)
+			return NULL;
+	}
+}
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+		       int flags)
+{
+	struct sigaction sa;
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_sigaction = handler;
+	sa.sa_flags = SA_SIGINFO | flags;
+	sigemptyset(&sa.sa_mask);
+	if (sigaction(sig, &sa, 0))
+		err(1, "sigaction");
+
+}
+
+static jmp_buf jmpbuf;
+
+static void sigsegv(int sig, siginfo_t *info, void *ctx_void)
+{
+	siglongjmp(jmpbuf, 1);
+}
+
+static void do_multicpu_tests(void)
+{
+	cpu_set_t cpuset;
+	pthread_t thread;
+	int failures = 0, iters = 5, i;
+	unsigned short orig_ss;
+
+	CPU_ZERO(&cpuset);
+	CPU_SET(1, &cpuset);
+	if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) {
+		printf("[SKIP]\tCannot set affinity to CPU 1\n");
+		return;
+	}
+
+	CPU_ZERO(&cpuset);
+	CPU_SET(0, &cpuset);
+	if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) {
+		printf("[SKIP]\tCannot set affinity to CPU 0\n");
+		return;
+	}
+
+	sethandler(SIGSEGV, sigsegv, 0);
+#ifdef __i386__
+	/* True 32-bit kernels send SIGILL instead of SIGSEGV on IRET faults. */
+	sethandler(SIGILL, sigsegv, 0);
+#endif
+
+	printf("[RUN]\tCross-CPU LDT invalidation\n");
+
+	if (pthread_create(&thread, 0, threadproc, 0) != 0)
+		err(1, "pthread_create");
+
+	asm volatile ("mov %%ss, %0" : "=rm" (orig_ss));
+
+	for (i = 0; i < 5; i++) {
+		if (sigsetjmp(jmpbuf, 1) != 0)
+			continue;
+
+		/* Make sure the thread is ready after the last test. */
+		while (ftx != 0)
+			;
+
+		struct user_desc desc = {
+			.entry_number    = 0,
+			.base_addr       = 0,
+			.limit           = 0xfffff,
+			.seg_32bit       = 1,
+			.contents        = 0, /* Data */
+			.read_exec_only  = 0,
+			.limit_in_pages  = 1,
+			.seg_not_present = 0,
+			.useable         = 0
+		};
+
+		if (safe_modify_ldt(0x11, &desc, sizeof(desc)) != 0) {
+			if (errno != ENOSYS)
+				err(1, "modify_ldt");
+			printf("[SKIP]\tmodify_ldt unavailable\n");
+			break;
+		}
+
+		/* Arm the thread. */
+		ftx = 1;
+		syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+
+		asm volatile ("mov %0, %%ss" : : "r" (0x7));
+
+		/* Go! */
+		ftx = 2;
+
+		while (ftx != 0)
+			;
+
+		/*
+		 * On success, modify_ldt will segfault us synchronously,
+		 * and we'll escape via siglongjmp.
+		 */
+
+		failures++;
+		asm volatile ("mov %0, %%ss" : : "rm" (orig_ss));
+	};
+
+	ftx = 100;  /* Kill the thread. */
+	syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+
+	if (pthread_join(thread, NULL) != 0)
+		err(1, "pthread_join");
+
+	if (failures) {
+		printf("[FAIL]\t%d of %d iterations failed\n", failures, iters);
+		nerrs++;
+	} else {
+		printf("[OK]\tAll %d iterations succeeded\n", iters);
+	}
+}
+
+static int finish_exec_test(void)
+{
+	/*
+	 * In a sensible world, this would be check_invalid_segment(0, 1);
+	 * For better or for worse, though, the LDT is inherited across exec.
+	 * We can probably change this safely, but for now we test it.
+	 */
+	check_valid_segment(0, 1,
+			    AR_DPL3 | AR_TYPE_XRCODE | AR_S | AR_P | AR_DB,
+			    42, true);
+
+	return nerrs ? 1 : 0;
+}
+
+static void do_exec_test(void)
+{
+	printf("[RUN]\tTest exec\n");
+
+	struct user_desc desc = {
+		.entry_number    = 0,
+		.base_addr       = 0,
+		.limit           = 42,
+		.seg_32bit       = 1,
+		.contents        = 2, /* Code, not conforming */
+		.read_exec_only  = 0,
+		.limit_in_pages  = 0,
+		.seg_not_present = 0,
+		.useable         = 0
+	};
+	install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | AR_S | AR_P | AR_DB);
+
+	pid_t child = fork();
+	if (child == 0) {
+		execl("/proc/self/exe", "ldt_gdt_test_exec", NULL);
+		printf("[FAIL]\tCould not exec self\n");
+		exit(1);	/* exec failed */
+	} else {
+		int status;
+		if (waitpid(child, &status, 0) != child ||
+		    !WIFEXITED(status)) {
+			printf("[FAIL]\tChild died\n");
+			nerrs++;
+		} else if (WEXITSTATUS(status) != 0) {
+			printf("[FAIL]\tChild failed\n");
+			nerrs++;
+		} else {
+			printf("[OK]\tChild succeeded\n");
+		}
+	}
+}
+
+int main(int argc, char **argv)
+{
+	if (argc == 1 && !strcmp(argv[0], "ldt_gdt_test_exec"))
+		return finish_exec_test();
+
+	do_simple_tests();
+
+	do_multicpu_tests();
+
+	do_exec_test();
+
+	return nerrs ? 1 : 0;
+}

tools/testing/selftests/x86/syscall_arg_fault.c

···
+/*
+ * syscall_arg_fault.c - tests faults 32-bit fast syscall stack args
+ * Copyright (c) 2015 Andrew Lutomirski
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/signal.h>
+#include <sys/ucontext.h>
+#include <err.h>
+#include <setjmp.h>
+#include <errno.h>
+
+/* Our sigaltstack scratch space. */
+static unsigned char altstack_data[SIGSTKSZ];
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+		       int flags)
+{
+	struct sigaction sa;
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_sigaction = handler;
+	sa.sa_flags = SA_SIGINFO | flags;
+	sigemptyset(&sa.sa_mask);
+	if (sigaction(sig, &sa, 0))
+		err(1, "sigaction");
+}
+
+static volatile sig_atomic_t sig_traps;
+static sigjmp_buf jmpbuf;
+
+static volatile sig_atomic_t n_errs;
+
+static void sigsegv(int sig, siginfo_t *info, void *ctx_void)
+{
+	ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+	if (ctx->uc_mcontext.gregs[REG_EAX] != -EFAULT) {
+		printf("[FAIL]\tAX had the wrong value: 0x%x\n",
+		       ctx->uc_mcontext.gregs[REG_EAX]);
+		n_errs++;
+	} else {
+		printf("[OK]\tSeems okay\n");
+	}
+
+	siglongjmp(jmpbuf, 1);
+}
+
+static void sigill(int sig, siginfo_t *info, void *ctx_void)
+{
+	printf("[SKIP]\tIllegal instruction\n");
+	siglongjmp(jmpbuf, 1);
+}
+
+int main()
+{
+	stack_t stack = {
+		.ss_sp = altstack_data,
+		.ss_size = SIGSTKSZ,
+	};
+	if (sigaltstack(&stack, NULL) != 0)
+		err(1, "sigaltstack");
+
+	sethandler(SIGSEGV, sigsegv, SA_ONSTACK);
+	sethandler(SIGILL, sigill, SA_ONSTACK);
+
+	/*
+	 * Exercise another nasty special case.  The 32-bit SYSCALL
+	 * and SYSENTER instructions (even in compat mode) each
+	 * clobber one register.  A Linux system call has a syscall
+	 * number and six arguments, and the user stack pointer
+	 * needs to live in some register on return.  That means
+	 * that we need eight registers, but SYSCALL and SYSENTER
+	 * only preserve seven registers.  As a result, one argument
+	 * ends up on the stack.  The stack is user memory, which
+	 * means that the kernel can fail to read it.
+	 *
+	 * The 32-bit fast system calls don't have a defined ABI:
+	 * we're supposed to invoke them through the vDSO.  So we'll
+	 * fudge it: we set all regs to invalid pointer values and
+	 * invoke the entry instruction.  The return will fail no
+	 * matter what, and we completely lose our program state,
+	 * but we can fix it up with a signal handler.
+	 */
+
+	printf("[RUN]\tSYSENTER with invalid state\n");
+	if (sigsetjmp(jmpbuf, 1) == 0) {
+		asm volatile (
+			"movl $-1, %%eax\n\t"
+			"movl $-1, %%ebx\n\t"
+			"movl $-1, %%ecx\n\t"
+			"movl $-1, %%edx\n\t"
+			"movl $-1, %%esi\n\t"
+			"movl $-1, %%edi\n\t"
+			"movl $-1, %%ebp\n\t"
+			"movl $-1, %%esp\n\t"
+			"sysenter"
+			: : : "memory", "flags");
+	}
+
+	printf("[RUN]\tSYSCALL with invalid state\n");
+	if (sigsetjmp(jmpbuf, 1) == 0) {
+		asm volatile (
+			"movl $-1, %%eax\n\t"
+			"movl $-1, %%ebx\n\t"
+			"movl $-1, %%ecx\n\t"
+			"movl $-1, %%edx\n\t"
+			"movl $-1, %%esi\n\t"
+			"movl $-1, %%edi\n\t"
+			"movl $-1, %%ebp\n\t"
+			"movl $-1, %%esp\n\t"
+			"syscall\n\t"
+			"pushl $0"	/* make sure we segfault cleanly */
+			: : : "memory", "flags");
+	}
+
+	return 0;
+}