Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull smp hotplug cleanups from Thomas Gleixner:
"This series is merily a cleanup of code copied around in arch/* and
not changing any of the real cpu hotplug horrors yet. I wish I'd had
something more substantial for 3.5, but I underestimated the lurking
horror..."

Fix up trivial conflicts in arch/{arm,sparc,x86}/Kconfig and
arch/sparc/include/asm/thread_info_32.h

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (79 commits)
um: Remove leftover declaration of alloc_task_struct_node()
task_allocator: Use config switches instead of magic defines
sparc: Use common threadinfo allocator
score: Use common threadinfo allocator
sh-use-common-threadinfo-allocator
mn10300: Use common threadinfo allocator
powerpc: Use common threadinfo allocator
mips: Use common threadinfo allocator
hexagon: Use common threadinfo allocator
m32r: Use common threadinfo allocator
frv: Use common threadinfo allocator
cris: Use common threadinfo allocator
x86: Use common threadinfo allocator
c6x: Use common threadinfo allocator
fork: Provide kmemcache based thread_info allocator
tile: Use common threadinfo allocator
fork: Provide weak arch_release_[task_struct|thread_info] functions
fork: Move thread info gfp flags to header
fork: Remove the weak insanity
sh: Remove cpu_idle_wait()
...

arch/Kconfig

···
 config USE_GENERIC_SMP_HELPERS
 	bool
 
+config GENERIC_SMP_IDLE_THREAD
+       bool
+
+# Select if arch init_task initializer is different to init/init_task.c
+config ARCH_INIT_TASK
+       bool
+
+# Select if arch has its private alloc_task_struct() function
+config ARCH_TASK_STRUCT_ALLOCATOR
+	bool
+
+# Select if arch has its private alloc_thread_info() function
+config ARCH_THREAD_INFO_ALLOCATOR
+	bool
+
 config HAVE_REGS_AND_STACK_ACCESS_API
 	bool
 	help

arch/alpha/Kconfig

···
 	select GENERIC_IRQ_SHOW
 	select ARCH_WANT_OPTIONAL_GPIOLIB
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
+	select GENERIC_SMP_IDLE_THREAD
 	help
 	  The Alpha is a 64-bit general-purpose processor designed and
 	  marketed by the Digital Equipment Corporation of blessed memory,

arch/alpha/kernel/Makefile

···
 asflags-y	:= $(KBUILD_CFLAGS)
 ccflags-y	:= -Wno-sign-compare
 
-obj-y    := entry.o traps.o process.o init_task.o osf_sys.o irq.o \
+obj-y    := entry.o traps.o process.o osf_sys.o irq.o \
 	    irq_alpha.o signal.o setup.o ptrace.o time.o \
 	    alpha_ksyms.o systbls.o err_common.o io.o
 

arch/alpha/kernel/init_task.c

···
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };

arch/alpha/kernel/smp.c

···
  * Bring one cpu online.
  */
 static int __cpuinit
-smp_boot_one_cpu(int cpuid)
+smp_boot_one_cpu(int cpuid, struct task_struct *idle)
 {
-	struct task_struct *idle;
 	unsigned long timeout;
-
-	/* Cook up an idler for this guy.  Note that the address we
-	   give to kernel_thread is irrelevant -- it's going to start
-	   where HWRPB.CPU_restart says to start.  But this gets all
-	   the other task-y sort of data structures set up like we
-	   wish.  We can't use kernel_thread since we must avoid
-	   rescheduling the child.  */
-	idle = fork_idle(cpuid);
-	if (IS_ERR(idle))
-		panic("failed fork for CPU %d", cpuid);
-
-	DBGS(("smp_boot_one_cpu: CPU %d state 0x%lx flags 0x%lx\n",
-	      cpuid, idle->state, idle->flags));
 
 	/* Signal the secondary to wait a moment.  */
 	smp_secondary_alive = -1;
···
 }
 
 int __cpuinit
-__cpu_up(unsigned int cpu)
+__cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-	smp_boot_one_cpu(cpu);
+	smp_boot_one_cpu(cpu, tidle);
 
 	return cpu_online(cpu) ? 0 : -ENOSYS;
 }

arch/arm/Kconfig

···
 	select CPU_PM if (SUSPEND || CPU_IDLE)
 	select GENERIC_PCI_IOMAP
 	select HAVE_BPF_JIT
+	select GENERIC_SMP_IDLE_THREAD
 	help
 	  The ARM series is a line of low-power-consumption RISC chip designs
 	  licensed by ARM Ltd and targeted at embedded applications and
···
 	  Internal node to signify that the ARCH has CPUFREQ support
 	  and that the relevant menu configurations are displayed for
 	  it.
-
-config ARCH_HAS_CPU_IDLE_WAIT
-       def_bool y
 
 config GENERIC_HWEIGHT
 	bool

arch/arm/Makefile

···
 CHECKFLAGS	+= -D__arm__
 
 #Default value
-head-y		:= arch/arm/kernel/head$(MMUEXT).o arch/arm/kernel/init_task.o
+head-y		:= arch/arm/kernel/head$(MMUEXT).o
 textofs-y	:= 0x00008000
 textofs-$(CONFIG_ARCH_CLPS711X) := 0x00028000
 # We don't want the htc bootloader to corrupt kernel during resume

arch/arm/include/asm/cpu.h

···
 struct cpuinfo_arm {
 	struct cpu	cpu;
 #ifdef CONFIG_SMP
-	struct task_struct *idle;
 	unsigned int	loops_per_jiffy;
 #endif
 };

arch/arm/include/asm/processor.h

···
 #define cpu_relax()			barrier()
 #endif
 
-void cpu_idle_wait(void);
-
 /*
  * Create a new kernel thread
  */

arch/arm/kernel/Makefile

···
 obj-$(CONFIG_DEBUG_LL)	+= debug.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 
-extra-y := $(head-y) init_task.o vmlinux.lds
+extra-y := $(head-y) vmlinux.lds

arch/arm/kernel/init_task.c

···
-/*
- *  linux/arch/arm/kernel/init_task.c
- */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <linux/uaccess.h>
-
-#include <asm/pgtable.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by making sure
- * the linker maps this in the .text segment right after head.S,
- * and making head.S ensure the proper alignment.
- *
- * The things we do for performance..
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);

arch/arm/kernel/process.c

···
 void (*arm_pm_restart)(char str, const char *cmd) = null_restart;
 EXPORT_SYMBOL_GPL(arm_pm_restart);
 
-static void do_nothing(void *unused)
-{
-}
-
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
- * pm_idle and update to new pm_idle value. Required while changing pm_idle
- * handler on SMP systems.
- *
- * Caller must have changed pm_idle to the new value before the call. Old
- * pm_idle value will not be used by any CPU after the return of this function.
- */
-void cpu_idle_wait(void)
-{
-	smp_mb();
-	/* kick all the CPUs so that they exit out of pm_idle */
-	smp_call_function(do_nothing, NULL, 1);
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);
-
 /*
  * This is our default idle handler.
  */

arch/arm/kernel/smp.c

···
 
 static DECLARE_COMPLETION(cpu_running);
 
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
 {
-	struct cpuinfo_arm *ci = &per_cpu(cpu_data, cpu);
-	struct task_struct *idle = ci->idle;
 	int ret;
-
-	/*
-	 * Spawn a new process manually, if not already done.
-	 * Grab a pointer to its task struct so we can mess with it
-	 */
-	if (!idle) {
-		idle = fork_idle(cpu);
-		if (IS_ERR(idle)) {
-			printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
-			return PTR_ERR(idle);
-		}
-		ci->idle = idle;
-	} else {
-		/*
-		 * Since this idle thread is being re-used, call
-		 * init_idle() to reinitialize the thread structure.
-		 */
-		init_idle(idle, cpu);
-	}
 
 	/*
 	 * We need to tell the secondary core where to find
···
 
 void __init smp_prepare_boot_cpu(void)
 {
-	unsigned int cpu = smp_processor_id();
-
-	per_cpu(cpu_data, cpu).idle = current;
 }
 
 void __init smp_prepare_cpus(unsigned int max_cpus)

arch/avr32/kernel/Makefile

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

arch/avr32/kernel/init_task.c

···
-/*
- * Copyright (C) 2004-2006 Atmel Corporation
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-
-#include <asm/pgtable.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure. Must be aligned on an 8192-byte boundary.
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);

arch/blackfin/Kconfig

···
 	select GENERIC_IRQ_PROBE
 	select IRQ_PER_CPU if SMP
 	select HAVE_NMI_WATCHDOG if NMI_WATCHDOG
+	select GENERIC_SMP_IDLE_THREAD
 
 config GENERIC_CSUM
 	def_bool y

arch/blackfin/Makefile

···
 CHECKFLAGS_SILICON = $(shell echo "" | $(CPP) $(KBUILD_CFLAGS) -dD - 2>/dev/null | awk '$$2 == "__SILICON_REVISION__" { print $$3 }')
 CHECKFLAGS += -D__SILICON_REVISION__=$(CHECKFLAGS_SILICON) -D__bfin__
 
-head-y   := arch/$(ARCH)/kernel/init_task.o
-
 core-y   += arch/$(ARCH)/kernel/ arch/$(ARCH)/mm/ arch/$(ARCH)/mach-common/
 
 # If we have a machine-specific directory, then include it in the build.

arch/blackfin/kernel/Makefile

···
 # arch/blackfin/kernel/Makefile
 #
 
-extra-y := init_task.o vmlinux.lds
+extra-y := vmlinux.lds
 
 obj-y := \
 	entry.o process.o bfin_ksyms.o ptrace.o setup.o signal.o \

arch/blackfin/kernel/init_task.c

···
-/*
- * Copyright 2004-2009 Analog Devices Inc.
- *
- * Licensed under the GPL-2 or later
- */
-
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <linux/fs.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry.
- */
-union thread_union init_thread_union
-    __init_task_data = {
-INIT_THREAD_INFO(init_task)};

arch/blackfin/mach-common/smp.c

···
 	return;
 }
 
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
 {
 	int ret;
-	struct blackfin_cpudata *ci = &per_cpu(cpu_data, cpu);
-	struct task_struct *idle = ci->idle;
 
-	if (idle) {
-		free_task(idle);
-		idle = NULL;
-	}
-
-	if (!idle) {
-		idle = fork_idle(cpu);
-		if (IS_ERR(idle)) {
-			printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
-			return PTR_ERR(idle);
-		}
-		ci->idle = idle;
-	} else {
-		init_idle(idle, cpu);
-	}
 	secondary_stack = task_stack_page(idle) + THREAD_SIZE;
 
 	ret = platform_boot_secondary(cpu, idle);

arch/c6x/include/asm/thread_info.h

···
 #ifdef CONFIG_4KSTACKS
 #define THREAD_SIZE		4096
 #define THREAD_SHIFT		12
-#define THREAD_ORDER		0
+#define THREAD_SIZE_ORDER	0
 #else
 #define THREAD_SIZE		8192
 #define THREAD_SHIFT		13
-#define THREAD_ORDER		1
+#define THREAD_SIZE_ORDER	1
 #endif
 
 #define THREAD_START_SP		(THREAD_SIZE - 8)
···
 	return ti;
 }
 
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-
-/* thread information allocation */
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO)
-#else
-#define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK)
-#endif
-
-#define alloc_thread_info_node(tsk, node)	\
-	((struct thread_info *)__get_free_pages(THREAD_FLAGS, THREAD_ORDER))
-
-#define free_thread_info(ti)	free_pages((unsigned long) (ti), THREAD_ORDER)
 #define get_thread_info(ti)	get_task_struct((ti)->task)
 #define put_thread_info(ti)	put_task_struct((ti)->task)
 #endif /* __ASSEMBLY__ */

arch/c6x/kernel/process.c

···
 
 extern asmlinkage void ret_from_fork(void);
 
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-
-/*
- * Initial thread structure.
- */
-union thread_union init_thread_union __init_task_data =	{
-	INIT_THREAD_INFO(init_task)
-};
-
-/*
- * Initial task structure.
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-
 /*
  * power off function, if any
  */

arch/cris/Kconfig

···
 	select HAVE_GENERIC_HARDIRQS
 	select GENERIC_IRQ_SHOW
 	select GENERIC_IOMAP
+	select GENERIC_SMP_IDLE_THREAD if ETRAX_ARCH_V32
 
 config HZ
 	int

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

···
 
 /* Bring one cpu online.*/
 static int __init
-smp_boot_one_cpu(int cpuid)
+smp_boot_one_cpu(int cpuid, struct task_struct idle)
 {
 	unsigned timeout;
-	struct task_struct *idle;
 	cpumask_t cpu_mask;
 
 	cpumask_clear(&cpu_mask);
-	idle = fork_idle(cpuid);
-	if (IS_ERR(idle))
-		panic("SMP: fork failed for CPU:%d", cpuid);
-
 	task_thread_info(idle)->cpu = cpuid;
 
 	/* Information to the CPU that is about to boot */
···
 		udelay(100);
 		barrier();
 	}
-
-	put_task_struct(idle);
-	idle = NULL;
 
 	printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
 	return -1;
···
  */
 unsigned long cache_decay_ticks = 1;
 
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-	smp_boot_one_cpu(cpu);
+	smp_boot_one_cpu(cpu, tidle);
 	return cpu_online(cpu) ? 0 : -ENOSYS;
 }
 

arch/cris/include/asm/processor.h

···
  */
 #define TASK_UNMAPPED_BASE      (PAGE_ALIGN(TASK_SIZE / 3))
 
-/* THREAD_SIZE is the size of the task_struct/kernel_stack combo.
+/* THREAD_SIZE is the size of the thread_info/kernel_stack combo.
  * normally, the stack is found by doing something like p + THREAD_SIZE
  * in CRIS, a page is 8192 bytes, which seems like a sane size
  */
-
 #define THREAD_SIZE       PAGE_SIZE
-#define KERNEL_STACK_SIZE PAGE_SIZE
+#define THREAD_SIZE_ORDER (0)
 
 /*
  * At user->kernel entry, the pt_regs struct is stacked on the top of the kernel-stack.

arch/cris/include/asm/thread_info.h

···
 
 #define init_thread_info	(init_thread_union.thread_info)
 
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-/* thread information allocation */
-#define alloc_thread_info_node(tsk, node)	\
-	((struct thread_info *) __get_free_pages(GFP_KERNEL, 1))
-#define free_thread_info(ti) free_pages((unsigned long) (ti), 1)
-
 #endif /* !__ASSEMBLY__ */
 
 /*

arch/cris/kernel/process.c

···
 //#define DEBUG
 
 /*
- * Initial task structure. Make this a per-architecture thing,
- * because different architectures tend to have different
- * alignment requirements and potentially different initial
- * setup.
- */
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);
-
-/*
  * The hlt_counter, disable_hlt and enable_hlt is just here as a hook if
  * there would ever be a halt sequence (for power save when idle) with
  * some largish delay when halting or resuming *and* a driver that can't

arch/frv/Makefile

···
 KBUILD_AFLAGS	+= -Wa,--gdwarf2
 endif
 
-head-y		:= arch/frv/kernel/head.o arch/frv/kernel/init_task.o
+head-y		:= arch/frv/kernel/head.o
 
 core-y		+= arch/frv/kernel/ arch/frv/mm/
 libs-y		+= arch/frv/lib/

arch/frv/include/asm/thread_info.h

···
 
 #define THREAD_SIZE		8192
 
-#define __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
-
 /*
  * low level task data that entry.S needs immediate access to
  * - this struct should fit entirely inside of one cache line
···
 register struct thread_info *__current_thread_info asm("gr15");
 
 #define current_thread_info() ({ __current_thread_info; })
-
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-
-/* thread information allocation */
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define alloc_thread_info_node(tsk, node)			\
-		kzalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#else
-#define alloc_thread_info_node(tsk, node)			\
-		kmalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#endif
-
-#define free_thread_info(info)	kfree(info)
 
 #endif /* __ASSEMBLY__ */
 

arch/frv/kernel/Makefile

···
 heads-y				:= head-uc-fr401.o head-uc-fr451.o head-uc-fr555.o
 heads-$(CONFIG_MMU)		:= head-mmu-fr451.o
 
-extra-y:= head.o init_task.o vmlinux.lds
+extra-y:= head.o vmlinux.lds
 
 obj-y := $(heads-y) entry.o entry-table.o break.o switch_to.o kernel_thread.o \
 	 kernel_execve.o process.o traps.o ptrace.o signal.o dma.o \

arch/frv/kernel/init_task.c

···
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);

arch/frv/kernel/process.c

···
 void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
 
-struct task_struct *alloc_task_struct_node(int node)
-{
-	struct task_struct *p = kmalloc_node(THREAD_SIZE, GFP_KERNEL, node);
-
-	if (p)
-		atomic_set((atomic_t *)(p+1), 1);
-	return p;
-}
-
-void free_task_struct(struct task_struct *p)
-{
-	if (atomic_dec_and_test((atomic_t *)(p+1)))
-		kfree(p);
-}
-
 static void core_sleep_idle(void)
 {
 #ifdef LED_DEBUG_SLEEP

arch/h8300/kernel/Makefile

···
 
 obj-y := process.o traps.o ptrace.o irq.o \
 	 sys_h8300.o time.o signal.o \
-         setup.o gpio.o init_task.o syscalls.o \
+         setup.o gpio.o syscalls.o \
 	 entry.o timer/
 
 obj-$(CONFIG_MODULES) += module.o h8300_ksyms.o 

arch/h8300/kernel/init_task.c

···
-/*
- *  linux/arch/h8300/kernel/init_task.c
- */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-__asm__(".align 4");
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);
-
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-

arch/hexagon/Kconfig

···
 	select HAVE_ARCH_TRACEHOOK
 	select NO_IOPORT
 	select GENERIC_IOMAP
+	select GENERIC_SMP_IDLE_THREAD
 	# mostly generic routines, with some accelerated ones
 	---help---
 	  Qualcomm Hexagon is a processor architecture designed for high

arch/hexagon/Makefile

···
 LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
 libs-y += $(LIBGCC)
 
-head-y := arch/hexagon/kernel/head.o \
-	arch/hexagon/kernel/init_task.o
+head-y := arch/hexagon/kernel/head.o
 
 core-y += arch/hexagon/kernel/ \
 	arch/hexagon/mm/ \

arch/hexagon/include/asm/thread_info.h

···
 
 #define THREAD_SHIFT		12
 #define THREAD_SIZE		(1<<THREAD_SHIFT)
-
-#if THREAD_SHIFT >= PAGE_SHIFT
 #define THREAD_SIZE_ORDER	(THREAD_SHIFT - PAGE_SHIFT)
-#else  /*  don't use standard allocator  */
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-extern struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node);
-extern void free_thread_info(struct thread_info *ti);
-#endif
-
 
 #ifndef __ASSEMBLY__
 

arch/hexagon/kernel/Makefile

···
-extra-y := head.o vmlinux.lds init_task.o
+extra-y := head.o vmlinux.lds
 
 obj-$(CONFIG_SMP) += smp.o topology.o
 

arch/hexagon/kernel/init_task.c

···
-/*
- * Init task definition
- *
- * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 and
- * only version 2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that 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.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- */
-
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/thread_info.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by making sure
- * the linker maps this in the .text segment right after head.S,
- * and making head.S ensure the proper alignment.
- */
-union thread_union init_thread_union
-	__attribute__((__section__(".data.init_task"),
-		__aligned__(THREAD_SIZE))) = {
-			INIT_THREAD_INFO(init_task)
-		};
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);

arch/hexagon/kernel/process.c

···
 }
 
 /*
- * Borrowed from PowerPC -- basically allow smaller kernel stacks if we
- * go crazy with the page sizes.
- */
-#if THREAD_SHIFT < PAGE_SHIFT
-
-static struct kmem_cache *thread_info_cache;
-
-struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
-{
-	struct thread_info *ti;
-
-	ti = kmem_cache_alloc_node(thread_info_cache, GFP_KERNEL, node);
-	if (unlikely(ti == NULL))
-		return NULL;
-#ifdef CONFIG_DEBUG_STACK_USAGE
-	memset(ti, 0, THREAD_SIZE);
-#endif
-	return ti;
-}
-
-void free_thread_info(struct thread_info *ti)
-{
-	kmem_cache_free(thread_info_cache, ti);
-}
-
-/*  Weak symbol; called by init/main.c  */
-
-void thread_info_cache_init(void)
-{
-	thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
-					      THREAD_SIZE, 0, NULL);
-	BUG_ON(thread_info_cache == NULL);
-}
-
-#endif /* THREAD_SHIFT < PAGE_SHIFT */
-
-/*
  * Required placeholder.
  */
 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)

arch/hexagon/kernel/smp.c

···
  * maintains control until "cpu_online(cpu)" is set.
  */
 
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
 {
-	struct task_struct *idle;
-	struct thread_info *thread;
+	struct thread_info *thread = (struct thread_info *)idle->stack;
 	void *stack_start;
 
-	/*  Create new init task for the CPU  */
-	idle = fork_idle(cpu);
-	if (IS_ERR(idle))
-		panic(KERN_ERR "fork_idle failed\n");
-
-	thread = (struct thread_info *)idle->stack;
 	thread->cpu = cpu;
 
 	/*  Boot to the head.  */

arch/ia64/Kconfig

···
 	select ARCH_WANT_OPTIONAL_GPIOLIB
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select GENERIC_IOMAP
+	select GENERIC_SMP_IDLE_THREAD
+	select ARCH_INIT_TASK
+	select ARCH_TASK_STRUCT_ALLOCATOR
+	select ARCH_THREAD_INFO_ALLOCATOR
 	default y
 	help
 	  The Itanium Processor Family is Intel's 64-bit successor to

arch/ia64/include/asm/processor.h

···
 enum idle_boot_override {IDLE_NO_OVERRIDE=0, IDLE_HALT, IDLE_FORCE_MWAIT,
 			 IDLE_NOMWAIT, IDLE_POLL};
 
-void cpu_idle_wait(void);
 void default_idle(void);
 
 #define ia64_platform_is(x) (strcmp(x, platform_name) == 0)

arch/ia64/include/asm/thread_info.h

···
 	},					\
 }
 
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-
 #ifndef ASM_OFFSETS_C
 /* how to get the thread information struct from C */
 #define current_thread_info()	((struct thread_info *) ((char *) current + IA64_TASK_SIZE))
···
 #endif
 #define end_of_stack(p) (unsigned long *)((void *)(p) + IA64_RBS_OFFSET)
 
-#define __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
 #define alloc_task_struct_node(node)						\
 ({										\
 	struct page *page = alloc_pages_node(node, GFP_KERNEL | __GFP_COMP,	\

arch/ia64/kernel/process.c

···
 }
 #endif /* CONFIG_HOTPLUG_CPU */
 
-static void do_nothing(void *unused)
-{
-}
-
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
- * pm_idle and update to new pm_idle value. Required while changing pm_idle
- * handler on SMP systems.
- *
- * Caller must have changed pm_idle to the new value before the call. Old
- * pm_idle value will not be used by any CPU after the return of this function.
- */
-void cpu_idle_wait(void)
-{
-	smp_mb();
-	/* kick all the CPUs so that they exit out of pm_idle */
-	smp_call_function(do_nothing, NULL, 1);
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);
-
 void __attribute__((noreturn))
 cpu_idle (void)
 {

arch/ia64/kernel/smpboot.c

···
 #endif
 
 /*
- * Store all idle threads, this can be reused instead of creating
- * a new thread. Also avoids complicated thread destroy functionality
- * for idle threads.
- */
-struct task_struct *idle_thread_array[NR_CPUS];
-
-/*
  * Global array allocated for NR_CPUS at boot time
  */
 struct sal_to_os_boot sal_boot_rendez_state[NR_CPUS];
···
 
 #define set_brendez_area(x) (sal_state_for_booting_cpu = &sal_boot_rendez_state[(x)]);
 
-#define get_idle_for_cpu(x)		(idle_thread_array[(x)])
-#define set_idle_for_cpu(x,p)	(idle_thread_array[(x)] = (p))
-
 #else
-
-#define get_idle_for_cpu(x)		(NULL)
-#define set_idle_for_cpu(x,p)
 #define set_brendez_area(x)
 #endif
 
···
 	return NULL;
 }
 
-struct create_idle {
-	struct work_struct work;
-	struct task_struct *idle;
-	struct completion done;
-	int cpu;
-};
-
-void __cpuinit
-do_fork_idle(struct work_struct *work)
-{
-	struct create_idle *c_idle =
-		container_of(work, struct create_idle, work);
-
-	c_idle->idle = fork_idle(c_idle->cpu);
-	complete(&c_idle->done);
-}
-
 static int __cpuinit
-do_boot_cpu (int sapicid, int cpu)
+do_boot_cpu (int sapicid, int cpu, struct task_struct *idle)
 {
 	int timeout;
-	struct create_idle c_idle = {
-		.work = __WORK_INITIALIZER(c_idle.work, do_fork_idle),
-		.cpu	= cpu,
-		.done	= COMPLETION_INITIALIZER(c_idle.done),
-	};
 
-	/*
-	 * We can't use kernel_thread since we must avoid to
-	 * reschedule the child.
-	 */
- 	c_idle.idle = get_idle_for_cpu(cpu);
- 	if (c_idle.idle) {
-		init_idle(c_idle.idle, cpu);
- 		goto do_rest;
-	}
-
-	schedule_work(&c_idle.work);
-	wait_for_completion(&c_idle.done);
-
-	if (IS_ERR(c_idle.idle))
-		panic("failed fork for CPU %d", cpu);
-
-	set_idle_for_cpu(cpu, c_idle.idle);
-
-do_rest:
-	task_for_booting_cpu = c_idle.idle;
-
+	task_for_booting_cpu = idle;
 	Dprintk("Sending wakeup vector %lu to AP 0x%x/0x%x.\n", ap_wakeup_vector, cpu, sapicid);
 
 	set_brendez_area(cpu);
···
 }
 
 int __cpuinit
-__cpu_up (unsigned int cpu)
+__cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
 	int ret;
 	int sapicid;
···
 
 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 	/* Processor goes to start_secondary(), sets online flag */
-	ret = do_boot_cpu(sapicid, cpu);
+	ret = do_boot_cpu(sapicid, cpu, tidle);
 	if (ret < 0)
 		return ret;
 

arch/m32r/Makefile

···
 
 CHECKFLAGS	+= -D__m32r__ -D__BIG_ENDIAN__=1
 
-head-y	:= arch/m32r/kernel/head.o arch/m32r/kernel/init_task.o
+head-y	:= arch/m32r/kernel/head.o
 
 LIBGCC	:= $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
 

arch/m32r/include/asm/thread_info.h

···
 
 #define PREEMPT_ACTIVE		0x10000000
 
-#define THREAD_SIZE (PAGE_SIZE << 1)
-
+#define THREAD_SIZE		(PAGE_SIZE << 1)
+#define THREAD_SIZE_ORDER	1
 /*
  * macros/functions for gaining access to the thread information structure
  */
···
 
 	return ti;
 }
-
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-
-/* thread information allocation */
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define alloc_thread_info_node(tsk, node)			\
-		kzalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#else
-#define alloc_thread_info_node(tsk, node)			\
-		kmalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#endif
-
-#define free_thread_info(info) kfree(info)
 
 #define TI_FLAG_FAULT_CODE_SHIFT	28
 

arch/m32r/kernel/Makefile

···
 # Makefile for the Linux/M32R kernel.
 #
 
-extra-y	:= head.o init_task.o vmlinux.lds
+extra-y	:= head.o vmlinux.lds
 
 obj-y	:= process.o entry.o traps.o align.o irq.o setup.o time.o \
 	m32r_ksyms.o sys_m32r.o signal.o ptrace.o

arch/m32r/kernel/init_task.c

···
-/* orig : i386 init_task.c */
-
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);
-

arch/m32r/kernel/smpboot.c

···
 /* Function Prototypes                                                       */
 /*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*/
 
-void smp_prepare_boot_cpu(void);
-void smp_prepare_cpus(unsigned int);
 static void init_ipi_lock(void);
 static void do_boot_cpu(int);
-int __cpu_up(unsigned int);
-void smp_cpus_done(unsigned int);
 
 int start_secondary(void *);
 static void smp_callin(void);
···
 	}
 }
 
-int __cpuinit __cpu_up(unsigned int cpu_id)
+int __cpuinit __cpu_up(unsigned int cpu_id, struct task_struct *tidle)
 {
 	int timeout;
 

arch/m68k/kernel/Makefile

···
 extra-$(CONFIG_SUN3)	:= sun3-head.o
 extra-y			+= vmlinux.lds
 
-obj-y	:= entry.o init_task.o irq.o m68k_ksyms.o module.o process.o ptrace.o
+obj-y	:= entry.o irq.o m68k_ksyms.o module.o process.o ptrace.o
 obj-y	+= setup.o signal.o sys_m68k.o syscalltable.o time.o traps.o
 
 obj-$(CONFIG_MMU_MOTOROLA) += ints.o vectors.o

arch/m68k/kernel/init_task.c

···
-/*
- *  linux/arch/m68knommu/kernel/init_task.c
- */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);
-
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD size aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-

arch/microblaze/kernel/Makefile

···
 extra-y := head.o vmlinux.lds
 
 obj-y += dma.o exceptions.o \
-	hw_exception_handler.o init_task.o intc.o irq.o \
+	hw_exception_handler.o intc.o irq.o \
 	process.o prom.o prom_parse.o ptrace.o \
 	reset.o setup.o signal.o sys_microblaze.o timer.o traps.o unwind.o
 

arch/microblaze/kernel/init_task.c

···
-/*
- * Copyright (C) 2009 Michal Simek <[e-mail]>
- * Copyright (C) 2009 PetaLogix
- * Copyright (C) 2006 Atmark Techno, Inc.
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- */
-
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-
-#include <asm/pgtable.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);

arch/mips/Kconfig

···
 	select HAVE_MEMBLOCK
 	select HAVE_MEMBLOCK_NODE_MAP
 	select ARCH_DISCARD_MEMBLOCK
+	select GENERIC_SMP_IDLE_THREAD
 
 menu "Machine selection"
 

arch/mips/Makefile

···
 
 OBJCOPYFLAGS		+= --remove-section=.reginfo
 
-head-y := arch/mips/kernel/head.o arch/mips/kernel/init_task.o
+head-y := arch/mips/kernel/head.o
 
 libs-y			+= arch/mips/lib/
 

arch/mips/include/asm/thread_info.h

···
 
 #define STACK_WARN	(THREAD_SIZE / 8)
 
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define alloc_thread_info_node(tsk, node) \
-		kzalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#else
-#define alloc_thread_info_node(tsk, node) \
-		kmalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#endif
-
-#define free_thread_info(info) kfree(info)
-
 #endif /* !__ASSEMBLY__ */
 
 #define PREEMPT_ACTIVE		0x10000000

arch/mips/kernel/Makefile

···
 # Makefile for the Linux/MIPS kernel.
 #
 
-extra-y		:= head.o init_task.o vmlinux.lds
+extra-y		:= head.o vmlinux.lds
 
 obj-y		+= cpu-probe.o branch.o entry.o genex.o irq.o process.o \
 		   ptrace.o reset.o setup.o signal.o syscall.o \

arch/mips/kernel/init_task.c

···
-#include <linux/mm.h>
-#include <linux/export.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-
-#include <asm/thread_info.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by making sure
- * the linker maps this in the .text segment right after head.S,
- * and making head.S ensure the proper alignment.
- *
- * The things we do for performance..
- */
-union thread_union init_thread_union __init_task_data
-	__attribute__((__aligned__(THREAD_SIZE))) =
-		{ INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);

arch/mips/kernel/smp.c

···
 	cpu_set(0, cpu_callin_map);
 }
 
-/*
- * Called once for each "cpu_possible(cpu)".  Needs to spin up the cpu
- * and keep control until "cpu_online(cpu)" is set.  Note: cpu is
- * physical, not logical.
- */
-static struct task_struct *cpu_idle_thread[NR_CPUS];
-
-struct create_idle {
-	struct work_struct work;
-	struct task_struct *idle;
-	struct completion done;
-	int cpu;
-};
-
-static void __cpuinit do_fork_idle(struct work_struct *work)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-	struct create_idle *c_idle =
-		container_of(work, struct create_idle, work);
-
-	c_idle->idle = fork_idle(c_idle->cpu);
-	complete(&c_idle->done);
-}
-
-int __cpuinit __cpu_up(unsigned int cpu)
-{
-	struct task_struct *idle;
-
-	/*
-	 * Processor goes to start_secondary(), sets online flag
-	 * The following code is purely to make sure
-	 * Linux can schedule processes on this slave.
-	 */
-	if (!cpu_idle_thread[cpu]) {
-		/*
-		 * Schedule work item to avoid forking user task
-		 * Ported from arch/x86/kernel/smpboot.c
-		 */
-		struct create_idle c_idle = {
-			.cpu    = cpu,
-			.done   = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
-		};
-
-		INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
-		schedule_work(&c_idle.work);
-		wait_for_completion(&c_idle.done);
-		idle = cpu_idle_thread[cpu] = c_idle.idle;
-
-		if (IS_ERR(idle))
-			panic(KERN_ERR "Fork failed for CPU %d", cpu);
-	} else {
-		idle = cpu_idle_thread[cpu];
-		init_idle(idle, cpu);
-	}
-
-	mp_ops->boot_secondary(cpu, idle);
+	mp_ops->boot_secondary(cpu, tidle);
 
 	/*
 	 * Trust is futile.  We should really have timeouts ...

arch/mn10300/Makefile

···
 endif
 
 
-head-y		:= arch/mn10300/kernel/head.o arch/mn10300/kernel/init_task.o
+head-y		:= arch/mn10300/kernel/head.o
 
 core-y		+= arch/mn10300/kernel/ arch/mn10300/mm/
 

arch/mn10300/include/asm/thread_info.h

···
 
 #ifdef CONFIG_4KSTACKS
 #define THREAD_SIZE		(4096)
+#define THREAD_SIZE_ORDER	(0)
 #else
 #define THREAD_SIZE		(8192)
+#define THREAD_SIZE_ORDER	(1)
 #endif
 
 #define STACK_WARN		(THREAD_SIZE / 8)
···
 	return sp;
 }
 
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-
-/* thread information allocation */
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define alloc_thread_info_node(tsk, node)			\
-		kzalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#else
-#define alloc_thread_info_node(tsk, node)			\
-		kmalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#endif
-
 #ifndef CONFIG_KGDB
-#define free_thread_info(ti)	kfree((ti))
-#else
-extern void free_thread_info(struct thread_info *);
+void arch_release_thread_info(struct thread_info *ti)
 #endif
 #define get_thread_info(ti)	get_task_struct((ti)->task)
 #define put_thread_info(ti)	put_task_struct((ti)->task)

arch/mn10300/kernel/Makefile

···
 #
 # Makefile for the MN10300-specific core kernel code
 #
-extra-y := head.o init_task.o vmlinux.lds
+extra-y := head.o vmlinux.lds
 
 fpu-obj-y := fpu-nofpu.o fpu-nofpu-low.o
 fpu-obj-$(CONFIG_FPU) := fpu.o fpu-low.o

arch/mn10300/kernel/init_task.c

···
-/* MN10300 Initial task definitions
- *
- * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
- * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);

arch/mn10300/kernel/kgdb.c

···
  * single-step state is cleared.  At this point the breakpoints should have
  * been removed by __switch_to().
  */
-void free_thread_info(struct thread_info *ti)
+void arch_release_thread_info(struct thread_info *ti)
 {
 	if (kgdb_sstep_thread == ti) {
 		kgdb_sstep_thread = NULL;
···
 		 * so force immediate reentry */
 		kgdb_breakpoint();
 	}
-	kfree(ti);
 }
 
 /*

arch/mn10300/kernel/smp.c

···
  * __cpu_up - Set smp_commenced_mask for the nominated CPU
  * @cpu: The target CPU.
  */
-int __devinit __cpu_up(unsigned int cpu)
+int __devinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
 	int timeout;
 

arch/openrisc/Makefile

···
 	KBUILD_CFLAGS += $(call cc-option,-msoft-div)
 endif
 
-head-y 		:= arch/openrisc/kernel/head.o arch/openrisc/kernel/init_task.o
+head-y 		:= arch/openrisc/kernel/head.o
 
 core-y		+= arch/openrisc/lib/ \
 		   arch/openrisc/kernel/ \

arch/openrisc/kernel/Makefile

···
 # Makefile for the linux kernel.
 #
 
-extra-y	:= head.o vmlinux.lds init_task.o
+extra-y	:= head.o vmlinux.lds
 
 obj-y	:= setup.o idle.o or32_ksyms.o process.o dma.o \
 	   traps.o time.o irq.o entry.o ptrace.o signal.o sys_or32.o \

arch/openrisc/kernel/init_task.c

···
-/*
- * OpenRISC init_task.c
- *
- * Linux architectural port borrowing liberally from similar works of
- * others.  All original copyrights apply as per the original source
- * declaration.
- *
- * Modifications for the OpenRISC architecture:
- * Copyright (C) 2003 Matjaz Breskvar <[e-mail]>
- * Copyright (C) 2010-2011 Jonas Bonn <[e-mail]>
- *
- *      This program is free software; you can redistribute it and/or
- *      modify it under the terms of the GNU General Public License
- *      as published by the Free Software Foundation; either version
- *      2 of the License, or (at your option) any later version.
- */
-
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <linux/export.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data = {
-	INIT_THREAD_INFO(init_task)
-};
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);

arch/parisc/Kconfig

···
 	select GENERIC_PCI_IOMAP
 	select IRQ_PER_CPU
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
+	select GENERIC_SMP_IDLE_THREAD
 
 	help
 	  The PA-RISC microprocessor is designed by Hewlett-Packard and used

arch/parisc/Makefile

···
 
 KBUILD_CFLAGS	+= $(cflags-y)
 
-kernel-y			:= mm/ kernel/ math-emu/ kernel/init_task.o
+kernel-y			:= mm/ kernel/ math-emu/
 kernel-$(CONFIG_HPUX)		+= hpux/
 
 core-y	+= $(addprefix arch/parisc/, $(kernel-y))

arch/parisc/kernel/Makefile

···
 # Makefile for arch/parisc/kernel
 #
 
-extra-y			:= init_task.o head.o vmlinux.lds
+extra-y			:= head.o vmlinux.lds
 
 obj-y	     	:= cache.o pacache.o setup.o traps.o time.o irq.o \
 		   pa7300lc.o syscall.o entry.o sys_parisc.o firmware.o \

arch/parisc/kernel/init_task.c

···
-/* 
- *    Static declaration of "init" task data structure.
- *
- *    Copyright (C) 2000 Paul Bame <bame at parisc-linux.org>
- *    Copyright (C) 2000-2001 John Marvin <jsm at parisc-linux.org>
- *    Copyright (C) 2001 Helge Deller <deller @ parisc-linux.org>
- *    Copyright (C) 2002 Matthew Wilcox <willy with parisc-linux.org>
- *
- *
- *    This program is free software; you can redistribute it and/or modify
- *    it under the terms of the GNU General Public License as published by
- *    the Free Software Foundation; either version 2 of the License, or
- *    (at your option) any later version.
- *
- *    This program is distributed in the hope that 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.
- *
- *    You should have received a copy of the GNU General Public License
- *    along with this program; if not, write to the Free Software
- *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- */
-
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-#include <asm/pgalloc.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial task structure.
- *
- * We need to make sure that this is 16384-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data
-	__attribute__((aligned(128))) =
-		{ INIT_THREAD_INFO(init_task) };
-
-#if PT_NLEVELS == 3
-/* NOTE: This layout exactly conforms to the hybrid L2/L3 page table layout
- * with the first pmd adjacent to the pgd and below it. gcc doesn't actually
- * guarantee that global objects will be laid out in memory in the same order 
- * as the order of declaration, so put these in different sections and use
- * the linker script to order them. */
-pmd_t pmd0[PTRS_PER_PMD] __attribute__ ((__section__ (".data..vm0.pmd"), aligned(PAGE_SIZE)));
-#endif
-
-pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__ ((__section__ (".data..vm0.pgd"), aligned(PAGE_SIZE)));
-pte_t pg0[PT_INITIAL * PTRS_PER_PTE] __attribute__ ((__section__ (".data..vm0.pte"), aligned(PAGE_SIZE)));
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-EXPORT_SYMBOL(init_task);
-
-__asm__(".data");
-struct task_struct init_task = INIT_TASK(init_task);

arch/parisc/kernel/smp.c

···
 /*
  * Bring one cpu online.
  */
-int __cpuinit smp_boot_one_cpu(int cpuid)
+int __cpuinit smp_boot_one_cpu(int cpuid, struct task_struct *idle)
 {
 	const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
-	struct task_struct *idle;
 	long timeout;
-
-	/* 
-	 * Create an idle task for this CPU.  Note the address wed* give 
-	 * to kernel_thread is irrelevant -- it's going to start
-	 * where OS_BOOT_RENDEVZ vector in SAL says to start.  But
-	 * this gets all the other task-y sort of data structures set
-	 * up like we wish.   We need to pull the just created idle task 
-	 * off the run queue and stuff it into the init_tasks[] array.  
-	 * Sheesh . . .
-	 */
-
-	idle = fork_idle(cpuid);
-	if (IS_ERR(idle))
-		panic("SMP: fork failed for CPU:%d", cpuid);
 
 	task_thread_info(idle)->cpu = cpuid;
 
···
 		udelay(100);
 		barrier();
 	}
-
-	put_task_struct(idle);
-	idle = NULL;
-
 	printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
 	return -1;
 
···
 }
 
 
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
 	if (cpu != 0 && cpu < parisc_max_cpus)
-		smp_boot_one_cpu(cpu);
+		smp_boot_one_cpu(cpu, tidle);
 
 	return cpu_online(cpu) ? 0 : -ENOSYS;
 }

arch/parisc/mm/init.c

···
 
 extern int  data_start;
 
+#if PT_NLEVELS == 3
+/* NOTE: This layout exactly conforms to the hybrid L2/L3 page table layout
+ * with the first pmd adjacent to the pgd and below it. gcc doesn't actually
+ * guarantee that global objects will be laid out in memory in the same order
+ * as the order of declaration, so put these in different sections and use
+ * the linker script to order them. */
+pmd_t pmd0[PTRS_PER_PMD] __attribute__ ((__section__ (".data..vm0.pmd"), aligned(PAGE_SIZE)));
+#endif
+
+pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__ ((__section__ (".data..vm0.pgd"), aligned(PAGE_SIZE)));
+pte_t pg0[PT_INITIAL * PTRS_PER_PTE] __attribute__ ((__section__ (".data..vm0.pte"), aligned(PAGE_SIZE)));
+
 #ifdef CONFIG_DISCONTIGMEM
 struct node_map_data node_data[MAX_NUMNODES] __read_mostly;
 unsigned char pfnnid_map[PFNNID_MAP_MAX] __read_mostly;

arch/powerpc/Kconfig

···
 	bool
 	default y if 64BIT
 
-config ARCH_HAS_CPU_IDLE_WAIT
-	bool
-	default y
-
 config GENERIC_HWEIGHT
 	bool
 	default y
···
 	select HAVE_BPF_JIT if PPC64
 	select HAVE_ARCH_JUMP_LABEL
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
+	select GENERIC_SMP_IDLE_THREAD
 
 config EARLY_PRINTK
 	bool

arch/powerpc/include/asm/processor.h

···
 enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
 
 extern int powersave_nap;	/* set if nap mode can be used in idle loop */
-void cpu_idle_wait(void);
 
 #ifdef CONFIG_PSERIES_IDLE
 extern void update_smt_snooze_delay(int snooze);

arch/powerpc/include/asm/thread_info.h

···
 #define init_thread_info	(init_thread_union.thread_info)
 #define init_stack		(init_thread_union.stack)
 
-/* thread information allocation */
-
-#if THREAD_SHIFT >= PAGE_SHIFT
-
 #define THREAD_SIZE_ORDER	(THREAD_SHIFT - PAGE_SHIFT)
-
-#else /* THREAD_SHIFT < PAGE_SHIFT */
-
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-
-extern struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node);
-extern void free_thread_info(struct thread_info *ti);
-
-#endif /* THREAD_SHIFT < PAGE_SHIFT */
 
 /* how to get the thread information struct from C */
 static inline struct thread_info *current_thread_info(void)

arch/powerpc/kernel/Makefile

···
 
 obj-y				:= cputable.o ptrace.o syscalls.o \
 				   irq.o align.o signal_32.o pmc.o vdso.o \
-				   init_task.o process.o systbl.o idle.o \
+				   process.o systbl.o idle.o \
 				   signal.o sysfs.o cacheinfo.o time.o \
 				   prom.o traps.o setup-common.o \
 				   udbg.o misc.o io.o dma.o \

arch/powerpc/kernel/idle.c

···
 	}
 }
 
-
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs come out of the old
- * idle loop and start using the new idle loop.
- * Required while changing idle handler on SMP systems.
- * Caller must have changed idle handler to the new value before the call.
- * This window may be larger on shared systems.
- */
-void cpu_idle_wait(void)
-{
-	int cpu;
-	smp_mb();
-
-	/* kick all the CPUs so that they exit out of old idle routine */
-	get_online_cpus();
-	for_each_online_cpu(cpu) {
-		if (cpu != smp_processor_id())
-			smp_send_reschedule(cpu);
-	}
-	put_online_cpus();
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);
-
 int powersave_nap;
 
 #ifdef CONFIG_SYSCTL

arch/powerpc/kernel/init_task.c

···
-#include <linux/mm.h>
-#include <linux/export.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-#include <asm/uaccess.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 16384-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);

arch/powerpc/kernel/process.c

···
 }
 #endif /* CONFIG_PPC64 */
 
-#if THREAD_SHIFT < PAGE_SHIFT
-
-static struct kmem_cache *thread_info_cache;
-
-struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
-{
-	struct thread_info *ti;
-
-	ti = kmem_cache_alloc_node(thread_info_cache, GFP_KERNEL, node);
-	if (unlikely(ti == NULL))
-		return NULL;
-#ifdef CONFIG_DEBUG_STACK_USAGE
-	memset(ti, 0, THREAD_SIZE);
-#endif
-	return ti;
-}
-
-void free_thread_info(struct thread_info *ti)
-{
-	kmem_cache_free(thread_info_cache, ti);
-}
-
-void thread_info_cache_init(void)
-{
-	thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
-					      THREAD_SIZE, 0, NULL);
-	BUG_ON(thread_info_cache == NULL);
-}
-
-#endif /* THREAD_SHIFT < PAGE_SHIFT */
-
 unsigned long arch_align_stack(unsigned long sp)
 {
 	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)

arch/powerpc/kernel/smp.c

···
 #define DBG(fmt...)
 #endif
 
-
-/* Store all idle threads, this can be reused instead of creating
-* a new thread. Also avoids complicated thread destroy functionality
-* for idle threads.
-*/
 #ifdef CONFIG_HOTPLUG_CPU
-/*
- * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
- * removed after init for !CONFIG_HOTPLUG_CPU.
- */
-static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
-#define get_idle_for_cpu(x)      (per_cpu(idle_thread_array, x))
-#define set_idle_for_cpu(x, p)   (per_cpu(idle_thread_array, x) = (p))
-
 /* State of each CPU during hotplug phases */
 static DEFINE_PER_CPU(int, cpu_state) = { 0 };
-
-#else
-static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
-#define get_idle_for_cpu(x)      (idle_thread_array[(x)])
-#define set_idle_for_cpu(x, p)   (idle_thread_array[(x)] = (p))
 #endif
 
 struct thread_info *secondary_ti;
···
 }
 #endif
 
-struct create_idle {
-	struct work_struct work;
-	struct task_struct *idle;
-	struct completion done;
-	int cpu;
-};
-
-static void __cpuinit do_fork_idle(struct work_struct *work)
+static void cpu_idle_thread_init(unsigned int cpu, struct task_struct *idle)
 {
-	struct create_idle *c_idle =
-		container_of(work, struct create_idle, work);
-
-	c_idle->idle = fork_idle(c_idle->cpu);
-	complete(&c_idle->done);
-}
-
-static int __cpuinit create_idle(unsigned int cpu)
-{
-	struct thread_info *ti;
-	struct create_idle c_idle = {
-		.cpu	= cpu,
-		.done	= COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
-	};
-	INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
-
-	c_idle.idle = get_idle_for_cpu(cpu);
-
-	/* We can't use kernel_thread since we must avoid to
-	 * reschedule the child. We use a workqueue because
-	 * we want to fork from a kernel thread, not whatever
-	 * userspace process happens to be trying to online us.
-	 */
-	if (!c_idle.idle) {
-		schedule_work(&c_idle.work);
-		wait_for_completion(&c_idle.done);
-	} else
-		init_idle(c_idle.idle, cpu);
-	if (IS_ERR(c_idle.idle)) {		
-		pr_err("Failed fork for CPU %u: %li", cpu, PTR_ERR(c_idle.idle));
-		return PTR_ERR(c_idle.idle);
-	}
-	ti = task_thread_info(c_idle.idle);
+	struct thread_info *ti = task_thread_info(idle);
 
 #ifdef CONFIG_PPC64
-	paca[cpu].__current = c_idle.idle;
+	paca[cpu].__current = idle;
 	paca[cpu].kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD;
 #endif
 	ti->cpu = cpu;
-	current_set[cpu] = ti;
-
-	return 0;
+	secondary_ti = current_set[cpu] = ti;
 }
 
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
 	int rc, c;
 
···
 	    (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 		return -EINVAL;
 
-	/* Make sure we have an idle thread */
-	rc = create_idle(cpu);
-	if (rc)
-		return rc;
-
-	secondary_ti = current_set[cpu];
+	cpu_idle_thread_init(cpu, tidle);
 
 	/* Make sure callin-map entry is 0 (can be leftover a CPU
 	 * hotplug

arch/s390/Kconfig

···
 	select ARCH_INLINE_WRITE_UNLOCK_BH
 	select ARCH_INLINE_WRITE_UNLOCK_IRQ
 	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
+	select GENERIC_SMP_IDLE_THREAD
 
 config SCHED_OMIT_FRAME_POINTER
 	def_bool y

arch/s390/Makefile

···
 
 head-y		:= arch/s390/kernel/head.o
 head-y		+= arch/s390/kernel/$(if $(CONFIG_64BIT),head64.o,head31.o)
-head-y		+= arch/s390/kernel/init_task.o
 
 # See arch/s390/Kbuild for content of core part of the kernel
 core-y		+= arch/s390/

arch/s390/include/asm/smp.h

···
 extern struct mutex smp_cpu_state_mutex;
 extern struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
 
-extern int __cpu_up(unsigned int cpu);
+extern int __cpu_up(unsigned int cpu, struct task_struct *tidle);
 
 extern void arch_send_call_function_single_ipi(int cpu);
 extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);

arch/s390/kernel/Makefile

···
 obj-y	+= $(if $(CONFIG_64BIT),entry64.o,entry.o)
 obj-y	+= $(if $(CONFIG_64BIT),reipl64.o,reipl.o)
 
-extra-y				+= head.o init_task.o vmlinux.lds
+extra-y				+= head.o vmlinux.lds
 extra-y				+= $(if $(CONFIG_64BIT),head64.o,head31.o)
 
 obj-$(CONFIG_MODULES)		+= s390_ksyms.o module.o

arch/s390/kernel/init_task.c

···
-/*
- *  arch/s390/kernel/init_task.c
- *
- *  S390 version
- *
- *  Derived from "arch/i386/kernel/init_task.c"
- */
-
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);

arch/s390/kernel/smp.c

···
 
 struct pcpu {
 	struct cpu cpu;
-	struct task_struct *idle;	/* idle process for the cpu */
 	struct _lowcore *lowcore;	/* lowcore page(s) for the cpu */
 	unsigned long async_stack;	/* async stack for the cpu */
 	unsigned long panic_stack;	/* panic stack for the cpu */
···
 	cpu_idle();
 }
 
-struct create_idle {
-	struct work_struct work;
-	struct task_struct *idle;
-	struct completion done;
-	int cpu;
-};
-
-static void __cpuinit smp_fork_idle(struct work_struct *work)
-{
-	struct create_idle *c_idle;
-
-	c_idle = container_of(work, struct create_idle, work);
-	c_idle->idle = fork_idle(c_idle->cpu);
-	complete(&c_idle->done);
-}
-
 /* Upping and downing of CPUs */
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-	struct create_idle c_idle;
 	struct pcpu *pcpu;
 	int rc;
 
···
 	if (pcpu_sigp_retry(pcpu, sigp_initial_cpu_reset, 0) !=
 	    sigp_order_code_accepted)
 		return -EIO;
-	if (!pcpu->idle) {
-		c_idle.done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done);
-		INIT_WORK_ONSTACK(&c_idle.work, smp_fork_idle);
-		c_idle.cpu = cpu;
-		schedule_work(&c_idle.work);
-		wait_for_completion(&c_idle.done);
-		if (IS_ERR(c_idle.idle))
-			return PTR_ERR(c_idle.idle);
-		pcpu->idle = c_idle.idle;
-	}
-	init_idle(pcpu->idle, cpu);
+
 	rc = pcpu_alloc_lowcore(pcpu, cpu);
 	if (rc)
 		return rc;
 	pcpu_prepare_secondary(pcpu, cpu);
-	pcpu_attach_task(pcpu, pcpu->idle);
+	pcpu_attach_task(pcpu, tidle);
 	pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 	while (!cpu_online(cpu))
 		cpu_relax();
···
 	struct pcpu *pcpu = pcpu_devices;
 
 	boot_cpu_address = stap();
-	pcpu->idle = current;
 	pcpu->state = CPU_STATE_CONFIGURED;
 	pcpu->address = boot_cpu_address;
 	pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();

arch/score/include/asm/thread_info.h

···
 #include <linux/const.h>
 
 /* thread information allocation */
-#define THREAD_SIZE_ORDER 	(1)
-#define THREAD_SIZE 		(PAGE_SIZE << THREAD_SIZE_ORDER)
-#define THREAD_MASK 		(THREAD_SIZE - _AC(1,UL))
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
+#define THREAD_SIZE_ORDER	(1)
+#define THREAD_SIZE		(PAGE_SIZE << THREAD_SIZE_ORDER)
+#define THREAD_MASK		(THREAD_SIZE - _AC(1,UL))
 
 #ifndef __ASSEMBLY__
 
···
 /* How to get the thread information struct from C. */
 register struct thread_info *__current_thread_info __asm__("r28");
 #define current_thread_info()	__current_thread_info
-
-#define alloc_thread_info_node(tsk, node) kmalloc_node(THREAD_SIZE, GFP_KERNEL, node)
-#define free_thread_info(info) kfree(info)
 
 #endif /* !__ASSEMBLY__ */
 

arch/score/kernel/Makefile

···
 
 extra-y	:= head.o vmlinux.lds
 
-obj-y += entry.o init_task.o irq.o process.o ptrace.o \
+obj-y += entry.o irq.o process.o ptrace.o \
 	setup.o signal.o sys_score.o time.o traps.o \
 	sys_call_table.o
 

arch/score/kernel/init_task.c

···
-/*
- * arch/score/kernel/init_task.c
- *
- * Score Processor version.
- *
- * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that 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.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see the file COPYING, or write
- * to the Free Software Foundation, Inc.,
- * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- */
-
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);

arch/sh/Kconfig

···
 	select RTC_LIB
 	select GENERIC_ATOMIC64
 	select GENERIC_IRQ_SHOW
+	select GENERIC_SMP_IDLE_THREAD
 	help
 	  The SuperH is a RISC processor targeted for use in embedded systems
 	  and consumer electronics; it was also used in the Sega Dreamcast
···
 	def_bool y
 
 config ARCH_HAS_DEFAULT_IDLE
-	def_bool y
-
-config ARCH_HAS_CPU_IDLE_WAIT
 	def_bool y
 
 config NO_IOPORT

arch/sh/Makefile

···
 
 export ld-bfd BITS
 
-head-y	:= arch/sh/kernel/init_task.o arch/sh/kernel/head_$(BITS).o
+head-y	:= arch/sh/kernel/head_$(BITS).o
 
 core-y				+= arch/sh/kernel/ arch/sh/mm/ arch/sh/boards/
 core-$(CONFIG_SH_FPU_EMU)	+= arch/sh/math-emu/

arch/sh/include/asm/processor.h

···
 	struct tlb_info itlb;
 	struct tlb_info dtlb;
 
-#ifdef CONFIG_SMP
-	struct task_struct *idle;
-#endif
-
 	unsigned int phys_bits;
 	unsigned long flags;
 } __attribute__ ((aligned(L1_CACHE_BYTES)));
···
 #define cpu_relax()	barrier()
 
 void default_idle(void);
-void cpu_idle_wait(void);
 void stop_this_cpu(void *);
 
 /* Forward decl */

arch/sh/include/asm/thread_info.h

···
 	return ti;
 }
 
-/* thread information allocation */
-#if THREAD_SHIFT >= PAGE_SHIFT
-
 #define THREAD_SIZE_ORDER	(THREAD_SHIFT - PAGE_SHIFT)
 
-#endif
-
-extern struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node);
-extern void free_thread_info(struct thread_info *ti);
 extern void arch_task_cache_init(void);
-#define arch_task_cache_init arch_task_cache_init
 extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
+extern void arch_release_task_struct(struct task_struct *tsk);
 extern void init_thread_xstate(void);
-
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
 
 #endif /* __ASSEMBLY__ */
 

arch/sh/kernel/Makefile

···
 # Makefile for the Linux/SuperH kernel.
 #
 
-extra-y	:= head_$(BITS).o init_task.o vmlinux.lds
+extra-y	:= head_$(BITS).o vmlinux.lds
 
 ifdef CONFIG_FUNCTION_TRACER
 # Do not profile debug and lowlevel utilities

arch/sh/kernel/idle.c

···
 		pm_idle = poll_idle;
 }
 
-static void do_nothing(void *unused)
-{
-}
-
 void stop_this_cpu(void *unused)
 {
 	local_irq_disable();
···
 	for (;;)
 		cpu_sleep();
 }
-
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
- * pm_idle and update to new pm_idle value. Required while changing pm_idle
- * handler on SMP systems.
- *
- * Caller must have changed pm_idle to the new value before the call. Old
- * pm_idle value will not be used by any CPU after the return of this function.
- */
-void cpu_idle_wait(void)
-{
-	smp_mb();
-	/* kick all the CPUs so that they exit out of pm_idle */
-	smp_call_function(do_nothing, NULL, 1);
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);

arch/sh/kernel/init_task.c

···
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <linux/fs.h>
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-struct pt_regs fake_swapper_regs;
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);

arch/sh/kernel/process.c

···
 	}
 }
 
-#if THREAD_SHIFT < PAGE_SHIFT
-static struct kmem_cache *thread_info_cache;
-
-struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
+void arch_release_task_struct(struct task_struct *tsk)
 {
-	struct thread_info *ti;
-#ifdef CONFIG_DEBUG_STACK_USAGE
-	gfp_t mask = GFP_KERNEL | __GFP_ZERO;
-#else
-	gfp_t mask = GFP_KERNEL;
-#endif
-
-	ti = kmem_cache_alloc_node(thread_info_cache, mask, node);
-	return ti;
+	free_thread_xstate(tsk);
 }
-
-void free_thread_info(struct thread_info *ti)
-{
-	free_thread_xstate(ti->task);
-	kmem_cache_free(thread_info_cache, ti);
-}
-
-void thread_info_cache_init(void)
-{
-	thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
-					      THREAD_SIZE, SLAB_PANIC, NULL);
-}
-#else
-struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
-{
-#ifdef CONFIG_DEBUG_STACK_USAGE
-	gfp_t mask = GFP_KERNEL | __GFP_ZERO;
-#else
-	gfp_t mask = GFP_KERNEL;
-#endif
-	struct page *page = alloc_pages_node(node, mask, THREAD_SIZE_ORDER);
-
-	return page ? page_address(page) : NULL;
-}
-
-void free_thread_info(struct thread_info *ti)
-{
-	free_thread_xstate(ti->task);
-	free_pages((unsigned long)ti, THREAD_SIZE_ORDER);
-}
-#endif /* THREAD_SHIFT < PAGE_SHIFT */
 
 void arch_task_cache_init(void)
 {

arch/sh/kernel/smp.c

···
 	void *thread_info;
 } stack_start;
 
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tsk)
 {
-	struct task_struct *tsk;
 	unsigned long timeout;
-
-	tsk = cpu_data[cpu].idle;
-	if (!tsk) {
-		tsk = fork_idle(cpu);
-		if (IS_ERR(tsk)) {
-			pr_err("Failed forking idle task for cpu %d\n", cpu);
-			return PTR_ERR(tsk);
-		}
-
-		cpu_data[cpu].idle = tsk;
-	}
 
 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 

arch/sparc/Kconfig

···
 	select GENERIC_PCI_IOMAP
 	select HAVE_NMI_WATCHDOG if SPARC64
 	select HAVE_BPF_JIT
+	select GENERIC_SMP_IDLE_THREAD
 
 config SPARC32
 	def_bool !64BIT
 	select GENERIC_ATOMIC64
 	select CLZ_TAB
+	select ARCH_THREAD_INFO_ALLOCATOR
 
 config SPARC64
 	def_bool 64BIT

arch/sparc/Makefile

···
 endif
 
 head-y                 := arch/sparc/kernel/head_$(BITS).o
-head-y                 += arch/sparc/kernel/init_task.o
 
 # See arch/sparc/Kbuild for the core part of the kernel
 core-y                 += arch/sparc/

arch/sparc/include/asm/leon.h

···
 #include <linux/interrupt.h>
 
 struct device_node;
+struct task_struct;
 extern unsigned int leon_build_device_irq(unsigned int real_irq,
 					   irq_flow_handler_t flow_handler,
 					   const char *name, int do_ack);
···
 extern void leon_clear_profile_irq(int cpu);
 extern void leon_smp_done(void);
 extern void leon_boot_cpus(void);
-extern int leon_boot_one_cpu(int i);
+extern int leon_boot_one_cpu(int i, struct task_struct *);
 void leon_init_smp(void);
 extern void cpu_idle(void);
 extern void init_IRQ(void);
···
 #define init_leon() do {} while (0)
 #define leon_smp_done() do {} while (0)
 #define leon_boot_cpus() do {} while (0)
-#define leon_boot_one_cpu(i) 1
+#define leon_boot_one_cpu(i, t) 1
 #define leon_init_smp() do {} while (0)
 
 #endif /* !defined(CONFIG_SPARC_LEON) */

arch/sparc/include/asm/thread_info_32.h

···
  */
 #define THREAD_INFO_ORDER  1
 
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-
 struct thread_info * alloc_thread_info_node(struct task_struct *tsk, int node);
 void free_thread_info(struct thread_info *);
 

arch/sparc/include/asm/thread_info_64.h

···
 
 /* thread information allocation */
 #if PAGE_SHIFT == 13
-#define __THREAD_INFO_ORDER	1
+#define THREAD_SIZE_ORDER	1
 #else /* PAGE_SHIFT == 13 */
-#define __THREAD_INFO_ORDER	0
+#define THREAD_SIZE_ORDER	0
 #endif /* PAGE_SHIFT == 13 */
-
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define THREAD_FLAGS (GFP_KERNEL | __GFP_ZERO)
-#else
-#define THREAD_FLAGS (GFP_KERNEL)
-#endif
-
-#define alloc_thread_info_node(tsk, node)				\
-({									\
-	struct page *page = alloc_pages_node(node, THREAD_FLAGS,	\
-					     __THREAD_INFO_ORDER);	\
-	struct thread_info *ret;					\
-									\
-	ret = page ? page_address(page) : NULL;				\
-	ret;								\
-})
-
-#define free_thread_info(ti) \
-	free_pages((unsigned long)(ti),__THREAD_INFO_ORDER)
 
 #define __thread_flag_byte_ptr(ti)	\
 	((unsigned char *)(&((ti)->flags)))

arch/sparc/kernel/Makefile

···
 ccflags-y := -Werror
 
 extra-y     := head_$(BITS).o
-extra-y     += init_task.o
 
 # Undefine sparc when processing vmlinux.lds - it is used
 # And teach CPP we are doing $(BITS) builds (for this case)

arch/sparc/kernel/init_task.c init/init_task.c

···
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/module.h>
-#include <linux/sched.h>
 #include <linux/init_task.h>
+#include <linux/export.h>
 #include <linux/mqueue.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
 
 #include <asm/pgtable.h>
 #include <asm/uaccess.h>
 
 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
 static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
+
+/* Initial task structure */
 struct task_struct init_task = INIT_TASK(init_task);
 EXPORT_SYMBOL(init_task);
 
-/* .text section in head.S is aligned at 8k boundary and this gets linked
- * right after that so that the init_thread_union is aligned properly as well.
- * If this is not aligned on a 8k boundary, then you should change code
- * in etrap.S which assumes it.
+/*
+ * Initial thread structure. Alignment of this is handled by a special
+ * linker map entry.
  */
 union thread_union init_thread_union __init_task_data =
 	{ INIT_THREAD_INFO(init_task) };

arch/sparc/kernel/leon_smp.c

···
 
 }
 
-int __cpuinit leon_boot_one_cpu(int i)
+int __cpuinit leon_boot_one_cpu(int i, struct task_struct *idle)
 {
-
-	struct task_struct *p;
 	int timeout;
 
-	/* Cook up an idler for this guy. */
-	p = fork_idle(i);
-
-	current_set[i] = task_thread_info(p);
+	current_set[i] = task_thread_info(idle);
 
 	/* See trampoline.S:leon_smp_cpu_startup for details...
 	 * Initialize the contexts table

arch/sparc/kernel/smp_32.c

···
 	set_cpu_possible(cpuid, true);
 }
 
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-	extern int __cpuinit smp4m_boot_one_cpu(int);
-	extern int __cpuinit smp4d_boot_one_cpu(int);
+	extern int __cpuinit smp4m_boot_one_cpu(int, struct task_struct *);
+	extern int __cpuinit smp4d_boot_one_cpu(int, struct task_struct *);
 	int ret=0;
 
 	switch(sparc_cpu_model) {
 	case sun4m:
-		ret = smp4m_boot_one_cpu(cpu);
+		ret = smp4m_boot_one_cpu(cpu, tidle);
 		break;
 	case sun4d:
-		ret = smp4d_boot_one_cpu(cpu);
+		ret = smp4d_boot_one_cpu(cpu, tidle);
 		break;
 	case sparc_leon:
-		ret = leon_boot_one_cpu(cpu);
+		ret = leon_boot_one_cpu(cpu, tidle);
 		break;
 	case sun4e:
 		printk("SUN4E\n");

arch/sparc/kernel/smp_64.c

···
  */
 static struct thread_info *cpu_new_thread = NULL;
 
-static int __cpuinit smp_boot_one_cpu(unsigned int cpu)
+static int __cpuinit smp_boot_one_cpu(unsigned int cpu, struct task_struct *idle)
 {
 	unsigned long entry =
 		(unsigned long)(&sparc64_cpu_startup);
 	unsigned long cookie =
 		(unsigned long)(&cpu_new_thread);
-	struct task_struct *p;
 	void *descr = NULL;
 	int timeout, ret;
 
-	p = fork_idle(cpu);
-	if (IS_ERR(p))
-		return PTR_ERR(p);
 	callin_flag = 0;
-	cpu_new_thread = task_thread_info(p);
+	cpu_new_thread = task_thread_info(idle);
 
 	if (tlb_type == hypervisor) {
 #if defined(CONFIG_SUN_LDOMS) && defined(CONFIG_HOTPLUG_CPU)
···
 	}
 }
 
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-	int ret = smp_boot_one_cpu(cpu);
+	int ret = smp_boot_one_cpu(cpu, tidle);
 
 	if (!ret) {
 		cpumask_set_cpu(cpu, &smp_commenced_mask);

arch/sparc/kernel/sun4d_smp.c

···
 	local_ops->cache_all();
 }
 
-int __cpuinit smp4d_boot_one_cpu(int i)
+int __cpuinit smp4d_boot_one_cpu(int i, struct task_struct *idle)
 {
 	unsigned long *entry = &sun4d_cpu_startup;
-	struct task_struct *p;
 	int timeout;
 	int cpu_node;
 
 	cpu_find_by_instance(i, &cpu_node, NULL);
-	/* Cook up an idler for this guy. */
-	p = fork_idle(i);
-	current_set[i] = task_thread_info(p);
-
+	current_set[i] = task_thread_info(idle);
 	/*
 	 * Initialize the contexts table
 	 * Since the call to prom_startcpu() trashes the structure,

arch/sparc/kernel/sun4m_smp.c

···
 	local_ops->cache_all();
 }
 
-int __cpuinit smp4m_boot_one_cpu(int i)
+int __cpuinit smp4m_boot_one_cpu(int i, struct task_struct *idle)
 {
 	unsigned long *entry = &sun4m_cpu_startup;
-	struct task_struct *p;
 	int timeout;
 	int cpu_node;
 
 	cpu_find_by_mid(i, &cpu_node);
+	current_set[i] = task_thread_info(idle);
 
-	/* Cook up an idler for this guy. */
-	p = fork_idle(i);
-	current_set[i] = task_thread_info(p);
 	/* See trampoline.S for details... */
 	entry += ((i - 1) * 3);
 

arch/tile/include/asm/thread_info.h

···
 
 #ifndef __ASSEMBLY__
 
+void arch_release_thread_info(struct thread_info *info);
+
 /* How to get the thread information struct from C. */
 register unsigned long stack_pointer __asm__("sp");
 
 #define current_thread_info() \
   ((struct thread_info *)(stack_pointer & -THREAD_SIZE))
-
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-extern struct thread_info *alloc_thread_info_node(struct task_struct *task, int node);
-extern void free_thread_info(struct thread_info *info);
 
 /* Sit on a nap instruction until interrupted. */
 extern void smp_nap(void);

arch/tile/kernel/Makefile

···
 #
 
 extra-y := vmlinux.lds head_$(BITS).o
-obj-y := backtrace.o entry.o init_task.o irq.o messaging.o \
+obj-y := backtrace.o entry.o irq.o messaging.o \
 	pci-dma.o proc.o process.o ptrace.o reboot.o \
 	setup.o signal.o single_step.o stack.o sys.o sysfs.o time.o traps.o \
 	intvec_$(BITS).o regs_$(BITS).o tile-desc_$(BITS).o

arch/tile/kernel/init_task.c

···
-/*
- * Copyright 2010 Tilera Corporation. All Rights Reserved.
- *
- *   This program is free software; you can redistribute it and/or
- *   modify it under the terms of the GNU General Public License
- *   as published by the Free Software Foundation, version 2.
- *
- *   This program is distributed in the hope that it will be useful, but
- *   WITHOUT ANY WARRANTY; without even the implied warranty of
- *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- *   NON INFRINGEMENT.  See the GNU General Public License for
- *   more details.
- */
-
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <linux/module.h>
-#include <linux/start_kernel.h>
-#include <linux/uaccess.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data = {
-	INIT_THREAD_INFO(init_task)
-};
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-
-/*
- * per-CPU stack and boot info.
- */
-DEFINE_PER_CPU(unsigned long, boot_sp) =
-	(unsigned long)init_stack + THREAD_SIZE;
-
-#ifdef CONFIG_SMP
-DEFINE_PER_CPU(unsigned long, boot_pc) = (unsigned long)start_kernel;
-#else
-/*
- * The variable must be __initdata since it references __init code.
- * With CONFIG_SMP it is per-cpu data, which is exempt from validation.
- */
-unsigned long __initdata boot_pc = (unsigned long)start_kernel;
-#endif

arch/tile/kernel/process.c

···
 	}
 }
 
-struct thread_info *alloc_thread_info_node(struct task_struct *task, int node)
-{
-	struct page *page;
-	gfp_t flags = GFP_KERNEL;
-
-#ifdef CONFIG_DEBUG_STACK_USAGE
-	flags |= __GFP_ZERO;
-#endif
-
-	page = alloc_pages_node(node, flags, THREAD_SIZE_ORDER);
-	if (!page)
-		return NULL;
-
-	return (struct thread_info *)page_address(page);
-}
-
 /*
- * Free a thread_info node, and all of its derivative
- * data structures.
+ * Release a thread_info structure
  */
-void free_thread_info(struct thread_info *info)
+void arch_release_thread_info(struct thread_info *info)
 {
 	struct single_step_state *step_state = info->step_state;
 
···
 		 */
 		kfree(step_state);
 	}
-
-	free_pages((unsigned long)info, THREAD_SIZE_ORDER);
 }
 
 static void save_arch_state(struct thread_struct *t);

arch/tile/kernel/setup.c

···
 
 static unsigned long __initdata node_percpu[MAX_NUMNODES];
 
+/*
+ * per-CPU stack and boot info.
+ */
+DEFINE_PER_CPU(unsigned long, boot_sp) =
+	(unsigned long)init_stack + THREAD_SIZE;
+
+#ifdef CONFIG_SMP
+DEFINE_PER_CPU(unsigned long, boot_pc) = (unsigned long)start_kernel;
+#else
+/*
+ * The variable must be __initdata since it references __init code.
+ * With CONFIG_SMP it is per-cpu data, which is exempt from validation.
+ */
+unsigned long __initdata boot_pc = (unsigned long)start_kernel;
+#endif
+
 #ifdef CONFIG_HIGHMEM
 /* Page frame index of end of lowmem on each controller. */
 unsigned long __cpuinitdata node_lowmem_end_pfn[MAX_NUMNODES];

arch/tile/kernel/smpboot.c

···
 	cpu_idle();
 }
 
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
 	/* Wait 5s total for all CPUs for them to come online */
 	static int timeout;

arch/um/include/asm/processor-generic.h

···
 	.request		= { 0 } \
 }
 
-extern struct task_struct *alloc_task_struct_node(int node);
-
 static inline void release_thread(struct task_struct *task)
 {
 }

arch/um/kernel/Makefile

···
 extra-y := vmlinux.lds
 clean-files :=
 
-obj-y = config.o exec.o exitcode.o init_task.o irq.o ksyms.o mem.o \
+obj-y = config.o exec.o exitcode.o irq.o ksyms.o mem.o \
 	physmem.o process.o ptrace.o reboot.o sigio.o \
 	signal.o smp.o syscall.o sysrq.o time.o tlb.o trap.o \
 	um_arch.o umid.o skas/

arch/um/kernel/init_task.c

···
-/*
- * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,intel.linux}.com)
- * Licensed under the GPL
- */
-
-#include "linux/sched.h"
-#include "linux/init_task.h"
-#include "linux/fs.h"
-#include "linux/module.h"
-#include "linux/mqueue.h"
-#include "asm/uaccess.h"
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);
-
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-union thread_union cpu0_irqstack
-	__attribute__((__section__(".data..init_irqstack"))) =
-		{ INIT_THREAD_INFO(init_task) };

arch/um/kernel/smp.c

···
 	set_cpu_online(smp_processor_id(), true);
 }
 
-int __cpu_up(unsigned int cpu)
+int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
 	cpu_set(cpu, smp_commenced_mask);
 	while (!cpu_online(cpu))

arch/um/kernel/um_arch.c

···
 #include <linux/seq_file.h>
 #include <linux/string.h>
 #include <linux/utsname.h>
+#include <linux/sched.h>
 #include <asm/pgtable.h>
 #include <asm/processor.h>
 #include <asm/setup.h>
···
 	.loops_per_jiffy	= 0,
 	.ipi_pipe		= { -1, -1 }
 };
+
+union thread_union cpu0_irqstack
+	__attribute__((__section__(".data..init_irqstack"))) =
+		{ INIT_THREAD_INFO(init_task) };
 
 unsigned long thread_saved_pc(struct task_struct *task)
 {

arch/unicore32/Makefile

···
 CHECKFLAGS		+= -D__unicore32__
 
 head-y			:= arch/unicore32/kernel/head.o
-head-y			+= arch/unicore32/kernel/init_task.o
 
 core-y			+= arch/unicore32/kernel/
 core-y			+= arch/unicore32/mm/

arch/unicore32/kernel/Makefile

···
 head-y				:= head.o
 obj-$(CONFIG_DEBUG_LL)		+= debug.o
 
-extra-y				:= $(head-y) init_task.o vmlinux.lds
+extra-y				:= $(head-y) vmlinux.lds

arch/unicore32/kernel/init_task.c

···
-/*
- * linux/arch/unicore32/kernel/init_task.c
- *
- * Code specific to PKUnity SoC and UniCore ISA
- *
- * Copyright (C) 2001-2010 GUAN Xue-tao
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/mqueue.h>
-#include <linux/uaccess.h>
-
-#include <asm/pgtable.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is 8192-byte aligned due to the
- * way process stacks are handled. This is done by making sure
- * the linker maps this in the .text segment right after head.S,
- * and making head.S ensure the proper alignment.
- *
- * The things we do for performance..
- */
-union thread_union init_thread_union __init_task_data = {
-	INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);

arch/x86/Kconfig

···
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select GENERIC_IOMAP
 	select DCACHE_WORD_ACCESS
+	select GENERIC_SMP_IDLE_THREAD
 
 config INSTRUCTION_DECODER
 	def_bool (KPROBES || PERF_EVENTS)
···
 
 config RWSEM_XCHGADD_ALGORITHM
 	def_bool X86_XADD
-
-config ARCH_HAS_CPU_IDLE_WAIT
-	def_bool y
 
 config GENERIC_CALIBRATE_DELAY
 	def_bool y

arch/x86/Makefile

···
 head-y := arch/x86/kernel/head_$(BITS).o
 head-y += arch/x86/kernel/head$(BITS).o
 head-y += arch/x86/kernel/head.o
-head-y += arch/x86/kernel/init_task.o
 
 libs-y  += arch/x86/lib/
 

arch/x86/include/asm/boot.h

···
 #ifdef CONFIG_X86_64
 #define MIN_KERNEL_ALIGN_LG2	PMD_SHIFT
 #else
-#define MIN_KERNEL_ALIGN_LG2	(PAGE_SHIFT + THREAD_ORDER)
+#define MIN_KERNEL_ALIGN_LG2	(PAGE_SHIFT + THREAD_SIZE_ORDER)
 #endif
 #define MIN_KERNEL_ALIGN	(_AC(1, UL) << MIN_KERNEL_ALIGN_LG2)
 

arch/x86/include/asm/page_32_types.h

···
  */
 #define __PAGE_OFFSET		_AC(CONFIG_PAGE_OFFSET, UL)
 
-#define THREAD_ORDER	1
-#define THREAD_SIZE 	(PAGE_SIZE << THREAD_ORDER)
+#define THREAD_SIZE_ORDER	1
+#define THREAD_SIZE		(PAGE_SIZE << THREAD_SIZE_ORDER)
 
 #define STACKFAULT_STACK 0
 #define DOUBLEFAULT_STACK 1

arch/x86/include/asm/page_64_types.h

···
 #ifndef _ASM_X86_PAGE_64_DEFS_H
 #define _ASM_X86_PAGE_64_DEFS_H
 
-#define THREAD_ORDER	1
-#define THREAD_SIZE  (PAGE_SIZE << THREAD_ORDER)
+#define THREAD_SIZE_ORDER	1
+#define THREAD_SIZE  (PAGE_SIZE << THREAD_SIZE_ORDER)
 #define CURRENT_MASK (~(THREAD_SIZE - 1))
 
 #define EXCEPTION_STACK_ORDER 0

arch/x86/include/asm/processor.h

···
 #define cpu_has_amd_erratum(x)	(false)
 #endif /* CONFIG_CPU_SUP_AMD */
 
-void cpu_idle_wait(void);
-
 extern unsigned long arch_align_stack(unsigned long sp);
 extern void free_init_pages(char *what, unsigned long begin, unsigned long end);
 

arch/x86/include/asm/smp.h

···
 /* Static state in head.S used to set up a CPU */
 extern unsigned long stack_start; /* Initial stack pointer address */
 
+struct task_struct;
+
 struct smp_ops {
 	void (*smp_prepare_boot_cpu)(void);
 	void (*smp_prepare_cpus)(unsigned max_cpus);
···
 	void (*stop_other_cpus)(int wait);
 	void (*smp_send_reschedule)(int cpu);
 
-	int (*cpu_up)(unsigned cpu);
+	int (*cpu_up)(unsigned cpu, struct task_struct *tidle);
 	int (*cpu_disable)(void);
 	void (*cpu_die)(unsigned int cpu);
 	void (*play_dead)(void);
···
 	smp_ops.smp_cpus_done(max_cpus);
 }
 
-static inline int __cpu_up(unsigned int cpu)
+static inline int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-	return smp_ops.cpu_up(cpu);
+	return smp_ops.cpu_up(cpu, tidle);
 }
 
 static inline int __cpu_disable(void)
···
 void native_smp_prepare_boot_cpu(void);
 void native_smp_prepare_cpus(unsigned int max_cpus);
 void native_smp_cpus_done(unsigned int max_cpus);
-int native_cpu_up(unsigned int cpunum);
+int native_cpu_up(unsigned int cpunum, struct task_struct *tidle);
 int native_cpu_disable(void);
 void native_cpu_die(unsigned int cpu);
 void native_play_dead(void);
···
 
 void native_send_call_func_ipi(const struct cpumask *mask);
 void native_send_call_func_single_ipi(int cpu);
+void x86_idle_thread_init(unsigned int cpu, struct task_struct *idle);
 
 void smp_store_cpu_info(int id);
 #define cpu_physical_id(cpu)	per_cpu(x86_cpu_to_apicid, cpu)

arch/x86/include/asm/thread_info.h

···
 
 #define PREEMPT_ACTIVE		0x10000000
 
-/* thread information allocation */
-#ifdef CONFIG_DEBUG_STACK_USAGE
-#define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO)
-#else
-#define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK)
-#endif
-
-#define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
-
-#define alloc_thread_info_node(tsk, node)				\
-({									\
-	struct page *page = alloc_pages_node(node, THREAD_FLAGS,	\
-					     THREAD_ORDER);		\
-	struct thread_info *ret = page ? page_address(page) : NULL;	\
-									\
-	ret;								\
-})
-
 #ifdef CONFIG_X86_32
 
 #define STACK_WARN	(THREAD_SIZE/8)
···
 
 #ifndef __ASSEMBLY__
 extern void arch_task_cache_init(void);
-extern void free_thread_info(struct thread_info *ti);
 extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
-#define arch_task_cache_init arch_task_cache_init
+extern void arch_release_task_struct(struct task_struct *tsk);
 #endif
 #endif /* _ASM_X86_THREAD_INFO_H */

arch/x86/kernel/Makefile

···
 # Makefile for the linux kernel.
 #
 
-extra-y                := head_$(BITS).o head$(BITS).o head.o init_task.o vmlinux.lds
+extra-y                := head_$(BITS).o head$(BITS).o head.o vmlinux.lds
 
 CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE)
 

arch/x86/kernel/apm_32.c

···
 		 * (pm_idle), Wait for all processors to update cached/local
 		 * copies of pm_idle before proceeding.
 		 */
-		cpu_idle_wait();
+		kick_all_cpus_sync();
 	}
 	if (((apm_info.bios.flags & APM_BIOS_DISENGAGED) == 0)
 	    && (apm_info.connection_version > 0x0100)) {

arch/x86/kernel/init_task.c

···
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/fs.h>
-#include <linux/mqueue.h>
-
-#include <asm/uaccess.h>
-#include <asm/pgtable.h>
-#include <asm/desc.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-
-/*
- * Initial thread structure.
- *
- * We need to make sure that this is THREAD_SIZE aligned due to the
- * way process stacks are handled. This is done by having a special
- * "init_task" linker map entry..
- */
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-/*
- * Initial task structure.
- *
- * All other task structs will be allocated on slabs in fork.c
- */
-struct task_struct init_task = INIT_TASK(init_task);
-EXPORT_SYMBOL(init_task);
-
-/*
- * per-CPU TSS segments. Threads are completely 'soft' on Linux,
- * no more per-task TSS's. The TSS size is kept cacheline-aligned
- * so they are allowed to end up in the .data..cacheline_aligned
- * section. Since TSS's are completely CPU-local, we want them
- * on exact cacheline boundaries, to eliminate cacheline ping-pong.
- */
-DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, init_tss) = INIT_TSS;
-

arch/x86/kernel/irq_32.c

···
 		return;
 
 	irqctx = page_address(alloc_pages_node(cpu_to_node(cpu),
-					       THREAD_FLAGS,
-					       THREAD_ORDER));
+					       THREADINFO_GFP,
+					       THREAD_SIZE_ORDER));
 	memset(&irqctx->tinfo, 0, sizeof(struct thread_info));
 	irqctx->tinfo.cpu		= cpu;
 	irqctx->tinfo.preempt_count	= HARDIRQ_OFFSET;
···
 	per_cpu(hardirq_ctx, cpu) = irqctx;
 
 	irqctx = page_address(alloc_pages_node(cpu_to_node(cpu),
-					       THREAD_FLAGS,
-					       THREAD_ORDER));
+					       THREADINFO_GFP,
+					       THREAD_SIZE_ORDER));
 	memset(&irqctx->tinfo, 0, sizeof(struct thread_info));
 	irqctx->tinfo.cpu		= cpu;
 	irqctx->tinfo.addr_limit	= MAKE_MM_SEG(0);

arch/x86/kernel/process.c

···
 #include <asm/debugreg.h>
 #include <asm/nmi.h>
 
+/*
+ * per-CPU TSS segments. Threads are completely 'soft' on Linux,
+ * no more per-task TSS's. The TSS size is kept cacheline-aligned
+ * so they are allowed to end up in the .data..cacheline_aligned
+ * section. Since TSS's are completely CPU-local, we want them
+ * on exact cacheline boundaries, to eliminate cacheline ping-pong.
+ */
+DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, init_tss) = INIT_TSS;
+
 #ifdef CONFIG_X86_64
 static DEFINE_PER_CPU(unsigned char, is_idle);
 static ATOMIC_NOTIFIER_HEAD(idle_notifier);
···
 	fpu_free(&tsk->thread.fpu);
 }
 
-void free_thread_info(struct thread_info *ti)
+void arch_release_task_struct(struct task_struct *tsk)
 {
-	free_thread_xstate(ti->task);
-	free_pages((unsigned long)ti, THREAD_ORDER);
+	free_thread_xstate(tsk);
 }
 
 void arch_task_cache_init(void)
···
 			halt();
 	}
 }
-
-static void do_nothing(void *unused)
-{
-}
-
-/*
- * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
- * pm_idle and update to new pm_idle value. Required while changing pm_idle
- * handler on SMP systems.
- *
- * Caller must have changed pm_idle to the new value before the call. Old
- * pm_idle value will not be used by any CPU after the return of this function.
- */
-void cpu_idle_wait(void)
-{
-	smp_mb();
-	/* kick all the CPUs so that they exit out of pm_idle */
-	smp_call_function(do_nothing, NULL, 1);
-}
-EXPORT_SYMBOL_GPL(cpu_idle_wait);
 
 /* Default MONITOR/MWAIT with no hints, used for default C1 state */
 static void mwait_idle(void)

arch/x86/kernel/smpboot.c

···
 /* State of each CPU */
 DEFINE_PER_CPU(int, cpu_state) = { 0 };
 
-/* Store all idle threads, this can be reused instead of creating
-* a new thread. Also avoids complicated thread destroy functionality
-* for idle threads.
-*/
 #ifdef CONFIG_HOTPLUG_CPU
-/*
- * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
- * removed after init for !CONFIG_HOTPLUG_CPU.
- */
-static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
-#define get_idle_for_cpu(x)      (per_cpu(idle_thread_array, x))
-#define set_idle_for_cpu(x, p)   (per_cpu(idle_thread_array, x) = (p))
-
 /*
  * We need this for trampoline_base protection from concurrent accesses when
  * off- and onlining cores wildly.
···
 
 void cpu_hotplug_driver_lock(void)
 {
-        mutex_lock(&x86_cpu_hotplug_driver_mutex);
+	mutex_lock(&x86_cpu_hotplug_driver_mutex);
 }
 
 void cpu_hotplug_driver_unlock(void)
 {
-        mutex_unlock(&x86_cpu_hotplug_driver_mutex);
+	mutex_unlock(&x86_cpu_hotplug_driver_mutex);
 }
 
 ssize_t arch_cpu_probe(const char *buf, size_t count) { return -1; }
 ssize_t arch_cpu_release(const char *buf, size_t count) { return -1; }
-#else
-static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
-#define get_idle_for_cpu(x)      (idle_thread_array[(x)])
-#define set_idle_for_cpu(x, p)   (idle_thread_array[(x)] = (p))
 #endif
 
 /* Number of siblings per CPU package */
···
 	return (send_status | accept_status);
 }
 
-struct create_idle {
-	struct work_struct work;
-	struct task_struct *idle;
-	struct completion done;
-	int cpu;
-};
-
-static void __cpuinit do_fork_idle(struct work_struct *work)
-{
-	struct create_idle *c_idle =
-		container_of(work, struct create_idle, work);
-
-	c_idle->idle = fork_idle(c_idle->cpu);
-	complete(&c_idle->done);
-}
-
 /* reduce the number of lines printed when booting a large cpu count system */
 static void __cpuinit announce_cpu(int cpu, int apicid)
 {
···
  * Returns zero if CPU booted OK, else error code from
  * ->wakeup_secondary_cpu.
  */
-static int __cpuinit do_boot_cpu(int apicid, int cpu)
+static int __cpuinit do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
 {
 	unsigned long boot_error = 0;
 	unsigned long start_ip;
 	int timeout;
-	struct create_idle c_idle = {
-		.cpu	= cpu,
-		.done	= COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
-	};
-
-	INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
 
 	alternatives_smp_switch(1);
 
-	c_idle.idle = get_idle_for_cpu(cpu);
+	idle->thread.sp = (unsigned long) (((struct pt_regs *)
+			  (THREAD_SIZE +  task_stack_page(idle))) - 1);
+	per_cpu(current_task, cpu) = idle;
 
-	/*
-	 * We can't use kernel_thread since we must avoid to
-	 * reschedule the child.
-	 */
-	if (c_idle.idle) {
-		c_idle.idle->thread.sp = (unsigned long) (((struct pt_regs *)
-			(THREAD_SIZE +  task_stack_page(c_idle.idle))) - 1);
-		init_idle(c_idle.idle, cpu);
-		goto do_rest;
-	}
-
-	schedule_work(&c_idle.work);
-	wait_for_completion(&c_idle.done);
-
-	if (IS_ERR(c_idle.idle)) {
-		printk("failed fork for CPU %d\n", cpu);
-		destroy_work_on_stack(&c_idle.work);
-		return PTR_ERR(c_idle.idle);
-	}
-
-	set_idle_for_cpu(cpu, c_idle.idle);
-do_rest:
-	per_cpu(current_task, cpu) = c_idle.idle;
 #ifdef CONFIG_X86_32
 	/* Stack for startup_32 can be just as for start_secondary onwards */
 	irq_ctx_init(cpu);
 #else
-	clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
+	clear_tsk_thread_flag(idle, TIF_FORK);
 	initial_gs = per_cpu_offset(cpu);
 	per_cpu(kernel_stack, cpu) =
-		(unsigned long)task_stack_page(c_idle.idle) -
+		(unsigned long)task_stack_page(idle) -
 		KERNEL_STACK_OFFSET + THREAD_SIZE;
 #endif
 	early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
 	initial_code = (unsigned long)start_secondary;
-	stack_start  = c_idle.idle->thread.sp;
+	stack_start  = idle->thread.sp;
 
 	/* start_ip had better be page-aligned! */
 	start_ip = trampoline_address();
···
 		 */
 		smpboot_restore_warm_reset_vector();
 	}
-
-	destroy_work_on_stack(&c_idle.work);
 	return boot_error;
 }
 
-int __cpuinit native_cpu_up(unsigned int cpu)
+int __cpuinit native_cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
 	int apicid = apic->cpu_present_to_apicid(cpu);
 	unsigned long flags;
···
 
 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 
-	err = do_boot_cpu(apicid, cpu);
+	err = do_boot_cpu(apicid, cpu, tidle);
 	if (err) {
 		pr_debug("do_boot_cpu failed %d\n", err);
 		return -EIO;

arch/x86/xen/smp.c

···
 		set_cpu_possible(cpu, false);
 	}
 
-	for_each_possible_cpu (cpu) {
-		struct task_struct *idle;
-
-		if (cpu == 0)
-			continue;
-
-		idle = fork_idle(cpu);
-		if (IS_ERR(idle))
-			panic("failed fork for CPU %d", cpu);
-
+	for_each_possible_cpu(cpu)
 		set_cpu_present(cpu, true);
-	}
 }
 
 static int __cpuinit
···
 	return 0;
 }
 
-static int __cpuinit xen_cpu_up(unsigned int cpu)
+static int __cpuinit xen_cpu_up(unsigned int cpu, struct task_struct *idle)
 {
-	struct task_struct *idle = idle_task(cpu);
 	int rc;
 
 	per_cpu(current_task, cpu) = idle;
···
 	xen_init_lock_cpu(0);
 }
 
-static int __cpuinit xen_hvm_cpu_up(unsigned int cpu)
+static int __cpuinit xen_hvm_cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
 	int rc;
-	rc = native_cpu_up(cpu);
+	rc = native_cpu_up(cpu, tidle);
 	WARN_ON (xen_smp_intr_init(cpu));
 	return rc;
 }

arch/xtensa/kernel/Makefile

···
 
 obj-y := align.o entry.o irq.o coprocessor.o process.o ptrace.o \
 	 setup.o signal.o syscall.o time.o traps.o vectors.o platform.o  \
-	 pci-dma.o init_task.o io.o
+	 pci-dma.o io.o
 
 obj-$(CONFIG_KGDB) += xtensa-stub.o
 obj-$(CONFIG_PCI) += pci.o

arch/xtensa/kernel/init_task.c

···
-/*
- * arch/xtensa/kernel/init_task.c
- *
- * Xtensa Processor version.
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 2007 Tensilica Inc.
- *
- * Chris Zankel <[e-mail]>
- */
-
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/init.h>
-#include <linux/init_task.h>
-#include <linux/module.h>
-#include <linux/mqueue.h>
-
-#include <asm/uaccess.h>
-
-static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
-static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
-union thread_union init_thread_union __init_task_data =
-	{ INIT_THREAD_INFO(init_task) };
-
-struct task_struct init_task = INIT_TASK(init_task);
-
-EXPORT_SYMBOL(init_task);

drivers/cpuidle/cpuidle.c

···
 	off = 1;
 }
 
-#if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT)
-static void cpuidle_kick_cpus(void)
-{
-	cpu_idle_wait();
-}
-#elif defined(CONFIG_SMP)
-# error "Arch needs cpu_idle_wait() equivalent here"
-#else /* !CONFIG_ARCH_HAS_CPU_IDLE_WAIT && !CONFIG_SMP */
-static void cpuidle_kick_cpus(void) {}
-#endif
-
 static int __cpuidle_register_device(struct cpuidle_device *dev);
 
 static inline int cpuidle_enter(struct cpuidle_device *dev,
···
 {
 	if (enabled_devices) {
 		initialized = 0;
-		cpuidle_kick_cpus();
+		kick_all_cpus_sync();
 	}
 }
 

include/linux/smp.h

···
 /*
  * Bring a CPU up
  */
-extern int __cpu_up(unsigned int cpunum);
+extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
 
 /*
  * Final polishing of CPUs
···
 
 int smp_call_function_any(const struct cpumask *mask,
 			  smp_call_func_t func, void *info, int wait);
+
+void kick_all_cpus_sync(void);
 
 /*
  * Generic and arch helpers
···
 {
 	return smp_call_function_single(0, func, info, wait);
 }
+
+static inline void kick_all_cpus_sync(void) {  }
 
 #endif /* !SMP */
 

include/linux/thread_info.h

···
 
 #ifdef __KERNEL__
 
+#ifdef CONFIG_DEBUG_STACK_USAGE
+# define THREADINFO_GFP		(GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO)
+#else
+# define THREADINFO_GFP		(GFP_KERNEL | __GFP_NOTRACK)
+#endif
+
 /*
  * flag set/clear/test wrappers
  * - pass TIF_xxxx constants to these functions

init/Makefile

···
 endif
 obj-$(CONFIG_GENERIC_CALIBRATE_DELAY) += calibrate.o
 
+ifneq ($(CONFIG_ARCH_INIT_TASK),y)
+obj-y                          += init_task.o
+endif
+
 mounts-y			:= do_mounts.o
 mounts-$(CONFIG_BLK_DEV_RAM)	+= do_mounts_rd.o
 mounts-$(CONFIG_BLK_DEV_INITRD)	+= do_mounts_initrd.o

kernel/Makefile

···
 obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
 obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
 obj-$(CONFIG_SMP) += smp.o
+obj-$(CONFIG_SMP) += smpboot.o
 ifneq ($(CONFIG_SMP),y)
 obj-y += up.o
 endif

kernel/cpu.c

···
 #include <linux/gfp.h>
 #include <linux/suspend.h>
 
+#include "smpboot.h"
+
 #ifdef CONFIG_SMP
 /* Serializes the updates to cpu_online_mask, cpu_present_mask */
 static DEFINE_MUTEX(cpu_add_remove_lock);
···
 	int ret, nr_calls = 0;
 	void *hcpu = (void *)(long)cpu;
 	unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
+	struct task_struct *idle;
 
 	if (cpu_online(cpu) || !cpu_present(cpu))
 		return -EINVAL;
 
 	cpu_hotplug_begin();
+
+	idle = idle_thread_get(cpu);
+	if (IS_ERR(idle)) {
+		ret = PTR_ERR(idle);
+		goto out;
+	}
+
 	ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls);
 	if (ret) {
 		nr_calls--;
···
 	}
 
 	/* Arch-specific enabling code. */
-	ret = __cpu_up(cpu);
+	ret = __cpu_up(cpu, idle);
 	if (ret != 0)
 		goto out_notify;
 	BUG_ON(!cpu_online(cpu));
···
 out_notify:
 	if (ret != 0)
 		__cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);
+out:
 	cpu_hotplug_done();
 
 	return ret;

kernel/fork.c

···
 	return total;
 }
 
-#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
-# define alloc_task_struct_node(node)		\
-		kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node)
-# define free_task_struct(tsk)			\
-		kmem_cache_free(task_struct_cachep, (tsk))
+#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
 static struct kmem_cache *task_struct_cachep;
+
+static inline struct task_struct *alloc_task_struct_node(int node)
+{
+	return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node);
+}
+
+void __weak arch_release_task_struct(struct task_struct *tsk) { }
+
+static inline void free_task_struct(struct task_struct *tsk)
+{
+	arch_release_task_struct(tsk);
+	kmem_cache_free(task_struct_cachep, tsk);
+}
 #endif
 
-#ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR
+#ifndef CONFIG_ARCH_THREAD_INFO_ALLOCATOR
+void __weak arch_release_thread_info(struct thread_info *ti) { }
+
+/*
+ * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a
+ * kmemcache based allocator.
+ */
+# if THREAD_SIZE >= PAGE_SIZE
 static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
 						  int node)
 {
-#ifdef CONFIG_DEBUG_STACK_USAGE
-	gfp_t mask = GFP_KERNEL | __GFP_ZERO;
-#else
-	gfp_t mask = GFP_KERNEL;
-#endif
-	struct page *page = alloc_pages_node(node, mask, THREAD_SIZE_ORDER);
+	struct page *page = alloc_pages_node(node, THREADINFO_GFP,
+					     THREAD_SIZE_ORDER);
 
 	return page ? page_address(page) : NULL;
 }
 
 static inline void free_thread_info(struct thread_info *ti)
 {
+	arch_release_thread_info(ti);
 	free_pages((unsigned long)ti, THREAD_SIZE_ORDER);
 }
+# else
+static struct kmem_cache *thread_info_cache;
+
+static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
+						  int node)
+{
+	return kmem_cache_alloc_node(thread_info_cache, THREADINFO_GFP, node);
+}
+
+static void free_thread_info(struct thread_info *ti)
+{
+	arch_release_thread_info(ti);
+	kmem_cache_free(thread_info_cache, ti);
+}
+
+void thread_info_cache_init(void)
+{
+	thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
+					      THREAD_SIZE, 0, NULL);
+	BUG_ON(thread_info_cache == NULL);
+}
+# endif
 #endif
 
 /* SLAB cache for signal_struct structures (tsk->signal) */
···
 }
 EXPORT_SYMBOL_GPL(__put_task_struct);
 
-/*
- * macro override instead of weak attribute alias, to workaround
- * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions.
- */
-#ifndef arch_task_cache_init
-#define arch_task_cache_init()
-#endif
+void __init __weak arch_task_cache_init(void) { }
 
 void __init fork_init(unsigned long mempages)
 {
-#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
+#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
 #ifndef ARCH_MIN_TASKALIGN
 #define ARCH_MIN_TASKALIGN	L1_CACHE_BYTES
 #endif

kernel/sched/Makefile

···
 obj-$(CONFIG_SCHED_AUTOGROUP) += auto_group.o
 obj-$(CONFIG_SCHEDSTATS) += stats.o
 obj-$(CONFIG_SCHED_DEBUG) += debug.o
-
-

kernel/sched/core.c

···
 
 #include "sched.h"
 #include "../workqueue_sched.h"
+#include "../smpboot.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/sched.h>
···
 	/* May be allocated at isolcpus cmdline parse time */
 	if (cpu_isolated_map == NULL)
 		zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
+	idle_thread_set_boot_cpu();
 #endif
 	init_sched_fair_class();
 

kernel/smp.c

···
 #include <linux/smp.h>
 #include <linux/cpu.h>
 
+#include "smpboot.h"
+
 #ifdef CONFIG_USE_GENERIC_SMP_HELPERS
 static struct {
 	struct list_head	queue;
···
 {
 	unsigned int cpu;
 
+	idle_threads_init();
+
 	/* FIXME: This should be done in userspace --RR */
 	for_each_present_cpu(cpu) {
 		if (num_online_cpus() >= setup_max_cpus)
···
 	}
 }
 EXPORT_SYMBOL(on_each_cpu_cond);
+
+static void do_nothing(void *unused)
+{
+}
+
+/**
+ * kick_all_cpus_sync - Force all cpus out of idle
+ *
+ * Used to synchronize the update of pm_idle function pointer. It's
+ * called after the pointer is updated and returns after the dummy
+ * callback function has been executed on all cpus. The execution of
+ * the function can only happen on the remote cpus after they have
+ * left the idle function which had been called via pm_idle function
+ * pointer. So it's guaranteed that nothing uses the previous pointer
+ * anymore.
+ */
+void kick_all_cpus_sync(void)
+{
+	/* Make sure the change is visible before we kick the cpus */
+	smp_mb();
+	smp_call_function(do_nothing, NULL, 1);
+}
+EXPORT_SYMBOL_GPL(kick_all_cpus_sync);

kernel/smpboot.c

···
+/*
+ * Common SMP CPU bringup/teardown functions
+ */
+#include <linux/err.h>
+#include <linux/smp.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/percpu.h>
+
+#include "smpboot.h"
+
+#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
+/*
+ * For the hotplug case we keep the task structs around and reuse
+ * them.
+ */
+static DEFINE_PER_CPU(struct task_struct *, idle_threads);
+
+struct task_struct * __cpuinit idle_thread_get(unsigned int cpu)
+{
+	struct task_struct *tsk = per_cpu(idle_threads, cpu);
+
+	if (!tsk)
+		return ERR_PTR(-ENOMEM);
+	init_idle(tsk, cpu);
+	return tsk;
+}
+
+void __init idle_thread_set_boot_cpu(void)
+{
+	per_cpu(idle_threads, smp_processor_id()) = current;
+}
+
+static inline void idle_init(unsigned int cpu)
+{
+	struct task_struct *tsk = per_cpu(idle_threads, cpu);
+
+	if (!tsk) {
+		tsk = fork_idle(cpu);
+		if (IS_ERR(tsk))
+			pr_err("SMP: fork_idle() failed for CPU %u\n", cpu);
+		else
+			per_cpu(idle_threads, cpu) = tsk;
+	}
+}
+
+/**
+ * idle_thread_init - Initialize the idle thread for a cpu
+ * @cpu:	The cpu for which the idle thread should be initialized
+ *
+ * Creates the thread if it does not exist.
+ */
+void __init idle_threads_init(void)
+{
+	unsigned int cpu;
+
+	for_each_possible_cpu(cpu) {
+		if (cpu != smp_processor_id())
+			idle_init(cpu);
+	}
+}
+#endif

kernel/smpboot.h

···
+#ifndef SMPBOOT_H
+#define SMPBOOT_H
+
+struct task_struct;
+
+int smpboot_prepare(unsigned int cpu);
+
+#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
+struct task_struct *idle_thread_get(unsigned int cpu);
+void idle_thread_set_boot_cpu(void);
+void idle_threads_init(void);
+#else
+static inline struct task_struct *idle_thread_get(unsigned int cpu) { return NULL; }
+static inline void idle_thread_set_boot_cpu(void) { }
+static inline void idle_threads_init(void) { }
+#endif
+
+#endif