arch/arm/kernel/process.c - maze/linux - Git at Google

 /*
  *  linux/arch/arm/kernel/process.c
  *
  *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
  *  Original Copyright (C) 1995  Linus Torvalds
  *
  * 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 <stdarg.h>

 #include <linux/config.h>
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/stddef.h>
 #include <linux/unistd.h>
 #include <linux/ptrace.h>
 #include <linux/slab.h>
 #include <linux/user.h>
 #include <linux/a.out.h>
 #include <linux/delay.h>
 #include <linux/reboot.h>
 #include <linux/interrupt.h>
 #include <linux/kallsyms.h>
 #include <linux/init.h>
 #include <linux/cpu.h>

 #include <asm/leds.h>
 #include <asm/processor.h>
 #include <asm/system.h>
 #include <asm/uaccess.h>
 #include <asm/mach/time.h>

 extern const char *processor_modes[];
 extern void setup_mm_for_reboot(char mode);

 static volatile int hlt_counter;

 #include <asm/arch/system.h>

 void disable_hlt(void)
 {
 	hlt_counter++;
 }

 EXPORT_SYMBOL(disable_hlt);

 void enable_hlt(void)
 {
 	hlt_counter--;
 }

 EXPORT_SYMBOL(enable_hlt);

 static int __init nohlt_setup(char *__unused)
 {
 	hlt_counter = 1;
 	return 1;
 }

 static int __init hlt_setup(char *__unused)
 {
 	hlt_counter = 0;
 	return 1;
 }

 __setup("nohlt", nohlt_setup);
 __setup("hlt", hlt_setup);

 /*
  * The following aren't currently used.
  */
 void (*pm_idle)(void);
 EXPORT_SYMBOL(pm_idle);

 void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);

 /*
  * This is our default idle handler.  We need to disable
  * interrupts here to ensure we don't miss a wakeup call.
  */
 void default_idle(void)
 {
 	if (hlt_counter)
 		cpu_relax();
 	else {
 		local_irq_disable();
 		if (!need_resched()) {
 			timer_dyn_reprogram();
 			arch_idle();
 		}
 		local_irq_enable();
 	}
 }

 /*
  * The idle thread.  We try to conserve power, while trying to keep
  * overall latency low.  The architecture specific idle is passed
  * a value to indicate the level of "idleness" of the system.
  */
 void cpu_idle(void)
 {
 	local_fiq_enable();

 	/* endless idle loop with no priority at all */
 	while (1) {
 		void (*idle)(void) = pm_idle;

 #ifdef CONFIG_HOTPLUG_CPU
 		if (cpu_is_offline(smp_processor_id())) {
 			leds_event(led_idle_start);
 			cpu_die();
 		}
 #endif

 		if (!idle)
 			idle = default_idle;
 		leds_event(led_idle_start);
 		while (!need_resched())
 			idle();
 		leds_event(led_idle_end);
 		preempt_enable_no_resched();
 		schedule();
 		preempt_disable();
 	}
 }

 static char reboot_mode = 'h';

 int __init reboot_setup(char *str)
 {
 	reboot_mode = str[0];
 	return 1;
 }

 __setup("reboot=", reboot_setup);

 void machine_halt(void)
 {
 }


 void machine_power_off(void)
 {
 	if (pm_power_off)
 		pm_power_off();
 }


 void machine_restart(char * __unused)
 {
 	/*
 	 * Clean and disable cache, and turn off interrupts
 	 */
 	cpu_proc_fin();

 	/*
 	 * Tell the mm system that we are going to reboot -
 	 * we may need it to insert some 1:1 mappings so that
 	 * soft boot works.
 	 */
 	setup_mm_for_reboot(reboot_mode);

 	/*
 	 * Now call the architecture specific reboot code.
 	 */
 	arch_reset(reboot_mode);

 	/*
 	 * Whoops - the architecture was unable to reboot.
 	 * Tell the user!
 	 */
 	mdelay(1000);
 	printk("Reboot failed -- System halted\n");
 	while (1);
 }

 void __show_regs(struct pt_regs *regs)
 {
 	unsigned long flags = condition_codes(regs);

 	printk("CPU: %d\n", smp_processor_id());
 	print_symbol("PC is at %s\n", instruction_pointer(regs));
 	print_symbol("LR is at %s\n", regs->ARM_lr);
 	printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
 	       "sp : %08lx  ip : %08lx  fp : %08lx\n",
 		instruction_pointer(regs),
 		regs->ARM_lr, print_tainted(), regs->ARM_sp,
 		regs->ARM_ip, regs->ARM_fp);
 	printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 		regs->ARM_r10, regs->ARM_r9,
 		regs->ARM_r8);
 	printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 		regs->ARM_r7, regs->ARM_r6,
 		regs->ARM_r5, regs->ARM_r4);
 	printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 		regs->ARM_r3, regs->ARM_r2,
 		regs->ARM_r1, regs->ARM_r0);
 	printk("Flags: %c%c%c%c",
 		flags & PSR_N_BIT ? 'N' : 'n',
 		flags & PSR_Z_BIT ? 'Z' : 'z',
 		flags & PSR_C_BIT ? 'C' : 'c',
 		flags & PSR_V_BIT ? 'V' : 'v');
 	printk("  IRQs o%s  FIQs o%s  Mode %s%s  Segment %s\n",
 		interrupts_enabled(regs) ? "n" : "ff",
 		fast_interrupts_enabled(regs) ? "n" : "ff",
 		processor_modes[processor_mode(regs)],
 		thumb_mode(regs) ? " (T)" : "",
 		get_fs() == get_ds() ? "kernel" : "user");
 	{
 		unsigned int ctrl, transbase, dac;
 		  __asm__ (
 		"	mrc p15, 0, %0, c1, c0\n"
 		"	mrc p15, 0, %1, c2, c0\n"
 		"	mrc p15, 0, %2, c3, c0\n"
 		: "=r" (ctrl), "=r" (transbase), "=r" (dac));
 		printk("Control: %04X  Table: %08X  DAC: %08X\n",
 		  	ctrl, transbase, dac);
 	}
 }

 void show_regs(struct pt_regs * regs)
 {
 	printk("\n");
 	printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
 	__show_regs(regs);
 	__backtrace();
 }

 void show_fpregs(struct user_fp *regs)
 {
 	int i;

 	for (i = 0; i < 8; i++) {
 		unsigned long *p;
 		char type;

 		p = (unsigned long *)(regs->fpregs + i);

 		switch (regs->ftype[i]) {
 			case 1: type = 'f'; break;
 			case 2: type = 'd'; break;
 			case 3: type = 'e'; break;
 			default: type = '?'; break;
 		}
 		if (regs->init_flag)
 			type = '?';

 		printk("  f%d(%c): %08lx %08lx %08lx%c",
 			i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
 	}


 	printk("FPSR: %08lx FPCR: %08lx\n",
 		(unsigned long)regs->fpsr,
 		(unsigned long)regs->fpcr);
 }

 /*
  * Task structure and kernel stack allocation.
  */
 static unsigned long *thread_info_head;
 static unsigned int nr_thread_info;

 #define EXTRA_TASK_STRUCT	4

 struct thread_info *alloc_thread_info(struct task_struct *task)
 {
 	struct thread_info *thread = NULL;

 	if (EXTRA_TASK_STRUCT) {
 		unsigned long *p = thread_info_head;

 		if (p) {
 			thread_info_head = (unsigned long *)p[0];
 			nr_thread_info -= 1;
 		}
 		thread = (struct thread_info *)p;
 	}

 	if (!thread)
 		thread = (struct thread_info *)
 			   __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);

 #ifdef CONFIG_DEBUG_STACK_USAGE
 	/*
 	 * The stack must be cleared if you want SYSRQ-T to
 	 * give sensible stack usage information
 	 */
 	if (thread)
 		memzero(thread, THREAD_SIZE);
 #endif
 	return thread;
 }

 void free_thread_info(struct thread_info *thread)
 {
 	if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) {
 		unsigned long *p = (unsigned long *)thread;
 		p[0] = (unsigned long)thread_info_head;
 		thread_info_head = p;
 		nr_thread_info += 1;
 	} else
 		free_pages((unsigned long)thread, THREAD_SIZE_ORDER);
 }

 /*
  * Free current thread data structures etc..
  */
 void exit_thread(void)
 {
 }

 static void default_fp_init(union fp_state *fp)
 {
 	memset(fp, 0, sizeof(union fp_state));
 }

 void (*fp_init)(union fp_state *) = default_fp_init;
 EXPORT_SYMBOL(fp_init);

 void flush_thread(void)
 {
 	struct thread_info *thread = current_thread_info();
 	struct task_struct *tsk = current;

 	memset(thread->used_cp, 0, sizeof(thread->used_cp));
 	memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 #if defined(CONFIG_IWMMXT)
 	iwmmxt_task_release(thread);
 #endif
 	fp_init(&thread->fpstate);
 #if defined(CONFIG_VFP)
 	vfp_flush_thread(&thread->vfpstate);
 #endif
 }

 void release_thread(struct task_struct *dead_task)
 {
 #if defined(CONFIG_VFP)
 	vfp_release_thread(&dead_task->thread_info->vfpstate);
 #endif
 #if defined(CONFIG_IWMMXT)
 	iwmmxt_task_release(dead_task->thread_info);
 #endif
 }

 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");

 int
 copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
 	    unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 {
 	struct thread_info *thread = p->thread_info;
 	struct pt_regs *childregs;

 	childregs = (void *)thread + THREAD_START_SP - sizeof(*regs);
 	*childregs = *regs;
 	childregs->ARM_r0 = 0;
 	childregs->ARM_sp = stack_start;

 	memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 	thread->cpu_context.sp = (unsigned long)childregs;
 	thread->cpu_context.pc = (unsigned long)ret_from_fork;

 	if (clone_flags & CLONE_SETTLS)
 		thread->tp_value = regs->ARM_r3;

 	return 0;
 }

 /*
  * fill in the fpe structure for a core dump...
  */
 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 {
 	struct thread_info *thread = current_thread_info();
 	int used_math = thread->used_cp[1] | thread->used_cp[2];

 	if (used_math)
 		memcpy(fp, &thread->fpstate.soft, sizeof (*fp));

 	return used_math != 0;
 }
 EXPORT_SYMBOL(dump_fpu);

 /*
  * fill in the user structure for a core dump..
  */
 void dump_thread(struct pt_regs * regs, struct user * dump)
 {
 	struct task_struct *tsk = current;

 	dump->magic = CMAGIC;
 	dump->start_code = tsk->mm->start_code;
 	dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);

 	dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
 	dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	dump->u_ssize = 0;

 	dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
 	dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
 	dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn.arm;
 	dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn.arm;
 	dump->u_debugreg[4] = tsk->thread.debug.nsaved;

 	if (dump->start_stack < 0x04000000)
 		dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;

 	dump->regs = *regs;
 	dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
 }
 EXPORT_SYMBOL(dump_thread);

 /*
  * Shuffle the argument into the correct register before calling the
  * thread function.  r1 is the thread argument, r2 is the pointer to
  * the thread function, and r3 points to the exit function.
  */
 extern void kernel_thread_helper(void);
 asm(	".section .text\n"
 "	.align\n"
 "	.type	kernel_thread_helper, #function\n"
 "kernel_thread_helper:\n"
 "	mov	r0, r1\n"
 "	mov	lr, r3\n"
 "	mov	pc, r2\n"
 "	.size	kernel_thread_helper, . - kernel_thread_helper\n"
 "	.previous");

 /*
  * Create a kernel thread.
  */
 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 {
 	struct pt_regs regs;

 	memset(&regs, 0, sizeof(regs));

 	regs.ARM_r1 = (unsigned long)arg;
 	regs.ARM_r2 = (unsigned long)fn;
 	regs.ARM_r3 = (unsigned long)do_exit;
 	regs.ARM_pc = (unsigned long)kernel_thread_helper;
 	regs.ARM_cpsr = SVC_MODE;

 	return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 }
 EXPORT_SYMBOL(kernel_thread);

 unsigned long get_wchan(struct task_struct *p)
 {
 	unsigned long fp, lr;
 	unsigned long stack_start, stack_end;
 	int count = 0;
 	if (!p || p == current || p->state == TASK_RUNNING)
 		return 0;

 	stack_start = (unsigned long)(p->thread_info + 1);
 	stack_end = ((unsigned long)p->thread_info) + THREAD_SIZE;

 	fp = thread_saved_fp(p);
 	do {
 		if (fp < stack_start || fp > stack_end)
 			return 0;
 		lr = pc_pointer (((unsigned long *)fp)[-1]);
 		if (!in_sched_functions(lr))
 			return lr;
 		fp = *(unsigned long *) (fp - 12);
 	} while (count ++ < 16);
 	return 0;
 }
 EXPORT_SYMBOL(get_wchan);
	/*
	* linux/arch/arm/kernel/process.c
	*
	* Copyright (C) 1996-2000 Russell King - Converted to ARM.
	* Original Copyright (C) 1995 Linus Torvalds
	*
	* 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 <stdarg.h>

	#include <linux/config.h>
	#include <linux/module.h>
	#include <linux/sched.h>
	#include <linux/kernel.h>
	#include <linux/mm.h>
	#include <linux/stddef.h>
	#include <linux/unistd.h>
	#include <linux/ptrace.h>
	#include <linux/slab.h>
	#include <linux/user.h>
	#include <linux/a.out.h>
	#include <linux/delay.h>
	#include <linux/reboot.h>
	#include <linux/interrupt.h>
	#include <linux/kallsyms.h>
	#include <linux/init.h>
	#include <linux/cpu.h>

	#include <asm/leds.h>
	#include <asm/processor.h>
	#include <asm/system.h>
	#include <asm/uaccess.h>
	#include <asm/mach/time.h>

	extern const char *processor_modes[];
	extern void setup_mm_for_reboot(char mode);

	static volatile int hlt_counter;

	#include <asm/arch/system.h>

	void disable_hlt(void)
	{
	hlt_counter++;
	}

	EXPORT_SYMBOL(disable_hlt);

	void enable_hlt(void)
	{
	hlt_counter--;
	}

	EXPORT_SYMBOL(enable_hlt);

	static int __init nohlt_setup(char *__unused)
	{
	hlt_counter = 1;
	return 1;
	}

	static int __init hlt_setup(char *__unused)
	{
	hlt_counter = 0;
	return 1;
	}

	__setup("nohlt", nohlt_setup);
	__setup("hlt", hlt_setup);

	/*
	* The following aren't currently used.
	*/
	void (*pm_idle)(void);
	EXPORT_SYMBOL(pm_idle);

	void (*pm_power_off)(void);
	EXPORT_SYMBOL(pm_power_off);

	/*
	* This is our default idle handler. We need to disable
	* interrupts here to ensure we don't miss a wakeup call.
	*/
	void default_idle(void)
	{
	if (hlt_counter)
	cpu_relax();
	else {
	local_irq_disable();
	if (!need_resched()) {
	timer_dyn_reprogram();
	arch_idle();
	}
	local_irq_enable();
	}
	}

	/*
	* The idle thread. We try to conserve power, while trying to keep
	* overall latency low. The architecture specific idle is passed
	* a value to indicate the level of "idleness" of the system.
	*/
	void cpu_idle(void)
	{
	local_fiq_enable();

	/* endless idle loop with no priority at all */
	while (1) {
	void (*idle)(void) = pm_idle;

	#ifdef CONFIG_HOTPLUG_CPU
	if (cpu_is_offline(smp_processor_id())) {
	leds_event(led_idle_start);
	cpu_die();
	}
	#endif

	if (!idle)
	idle = default_idle;
	leds_event(led_idle_start);
	while (!need_resched())
	idle();
	leds_event(led_idle_end);
	preempt_enable_no_resched();
	schedule();
	preempt_disable();
	}
	}

	static char reboot_mode = 'h';

	int __init reboot_setup(char *str)
	{
	reboot_mode = str[0];
	return 1;
	}

	__setup("reboot=", reboot_setup);

	void machine_halt(void)
	{
	}


	void machine_power_off(void)
	{
	if (pm_power_off)
	pm_power_off();
	}


	void machine_restart(char * __unused)
	{
	/*
	* Clean and disable cache, and turn off interrupts
	*/
	cpu_proc_fin();

	/*
	* Tell the mm system that we are going to reboot -
	* we may need it to insert some 1:1 mappings so that
	* soft boot works.
	*/
	setup_mm_for_reboot(reboot_mode);

	/*
	* Now call the architecture specific reboot code.
	*/
	arch_reset(reboot_mode);

	/*
	* Whoops - the architecture was unable to reboot.
	* Tell the user!
	*/
	mdelay(1000);
	printk("Reboot failed -- System halted\n");
	while (1);
	}

	void __show_regs(struct pt_regs *regs)
	{
	unsigned long flags = condition_codes(regs);

	printk("CPU: %d\n", smp_processor_id());
	print_symbol("PC is at %s\n", instruction_pointer(regs));
	print_symbol("LR is at %s\n", regs->ARM_lr);
	printk("pc : [<%08lx>] lr : [<%08lx>] %s\n"
	"sp : %08lx ip : %08lx fp : %08lx\n",
	instruction_pointer(regs),
	regs->ARM_lr, print_tainted(), regs->ARM_sp,
	regs->ARM_ip, regs->ARM_fp);
	printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
	regs->ARM_r10, regs->ARM_r9,
	regs->ARM_r8);
	printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
	regs->ARM_r7, regs->ARM_r6,
	regs->ARM_r5, regs->ARM_r4);
	printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
	regs->ARM_r3, regs->ARM_r2,
	regs->ARM_r1, regs->ARM_r0);
	printk("Flags: %c%c%c%c",
	flags & PSR_N_BIT ? 'N' : 'n',
	flags & PSR_Z_BIT ? 'Z' : 'z',
	flags & PSR_C_BIT ? 'C' : 'c',
	flags & PSR_V_BIT ? 'V' : 'v');
	printk(" IRQs o%s FIQs o%s Mode %s%s Segment %s\n",
	interrupts_enabled(regs) ? "n" : "ff",
	fast_interrupts_enabled(regs) ? "n" : "ff",
	processor_modes[processor_mode(regs)],
	thumb_mode(regs) ? " (T)" : "",
	get_fs() == get_ds() ? "kernel" : "user");
	{
	unsigned int ctrl, transbase, dac;
	__asm__ (
	" mrc p15, 0, %0, c1, c0\n"
	" mrc p15, 0, %1, c2, c0\n"
	" mrc p15, 0, %2, c3, c0\n"
	: "=r" (ctrl), "=r" (transbase), "=r" (dac));
	printk("Control: %04X Table: %08X DAC: %08X\n",
	ctrl, transbase, dac);
	}
	}

	void show_regs(struct pt_regs * regs)
	{
	printk("\n");
	printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
	__show_regs(regs);
	__backtrace();
	}

	void show_fpregs(struct user_fp *regs)
	{
	int i;

	for (i = 0; i < 8; i++) {
	unsigned long *p;
	char type;

	p = (unsigned long *)(regs->fpregs + i);

	switch (regs->ftype[i]) {
	case 1: type = 'f'; break;
	case 2: type = 'd'; break;
	case 3: type = 'e'; break;
	default: type = '?'; break;
	}
	if (regs->init_flag)
	type = '?';

	printk(" f%d(%c): %08lx %08lx %08lx%c",
	i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
	}


	printk("FPSR: %08lx FPCR: %08lx\n",
	(unsigned long)regs->fpsr,
	(unsigned long)regs->fpcr);
	}

	/*
	* Task structure and kernel stack allocation.
	*/
	static unsigned long *thread_info_head;
	static unsigned int nr_thread_info;

	#define EXTRA_TASK_STRUCT 4

	struct thread_info alloc_thread_info(struct task_struct task)
	{
	struct thread_info *thread = NULL;

	if (EXTRA_TASK_STRUCT) {
	unsigned long *p = thread_info_head;

	if (p) {
	thread_info_head = (unsigned long *)p[0];
	nr_thread_info -= 1;
	}
	thread = (struct thread_info *)p;
	}

	if (!thread)
	thread = (struct thread_info *)
	__get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);

	#ifdef CONFIG_DEBUG_STACK_USAGE
	/*
	* The stack must be cleared if you want SYSRQ-T to
	* give sensible stack usage information
	*/
	if (thread)
	memzero(thread, THREAD_SIZE);
	#endif
	return thread;
	}

	void free_thread_info(struct thread_info *thread)
	{
	if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) {
	unsigned long p = (unsigned long )thread;
	p[0] = (unsigned long)thread_info_head;
	thread_info_head = p;
	nr_thread_info += 1;
	} else
	free_pages((unsigned long)thread, THREAD_SIZE_ORDER);
	}

	/*
	* Free current thread data structures etc..
	*/
	void exit_thread(void)
	{
	}

	static void default_fp_init(union fp_state *fp)
	{
	memset(fp, 0, sizeof(union fp_state));
	}

	void (fp_init)(union fp_state ) = default_fp_init;
	EXPORT_SYMBOL(fp_init);

	void flush_thread(void)
	{
	struct thread_info *thread = current_thread_info();
	struct task_struct *tsk = current;

	memset(thread->used_cp, 0, sizeof(thread->used_cp));
	memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
	#if defined(CONFIG_IWMMXT)
	iwmmxt_task_release(thread);
	#endif
	fp_init(&thread->fpstate);
	#if defined(CONFIG_VFP)
	vfp_flush_thread(&thread->vfpstate);
	#endif
	}

	void release_thread(struct task_struct *dead_task)
	{
	#if defined(CONFIG_VFP)
	vfp_release_thread(&dead_task->thread_info->vfpstate);
	#endif
	#if defined(CONFIG_IWMMXT)
	iwmmxt_task_release(dead_task->thread_info);
	#endif
	}

	asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");

	int
	copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
	unsigned long stk_sz, struct task_struct p, struct pt_regs regs)
	{
	struct thread_info *thread = p->thread_info;
	struct pt_regs *childregs;

	childregs = (void )thread + THREAD_START_SP - sizeof(regs);
	childregs = regs;
	childregs->ARM_r0 = 0;
	childregs->ARM_sp = stack_start;

	memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
	thread->cpu_context.sp = (unsigned long)childregs;
	thread->cpu_context.pc = (unsigned long)ret_from_fork;

	if (clone_flags & CLONE_SETTLS)
	thread->tp_value = regs->ARM_r3;

	return 0;
	}

	/*
	* fill in the fpe structure for a core dump...
	*/
	int dump_fpu (struct pt_regs regs, struct user_fp fp)
	{
	struct thread_info *thread = current_thread_info();
	int used_math = thread->used_cp[1] \| thread->used_cp[2];

	if (used_math)
	memcpy(fp, &thread->fpstate.soft, sizeof (*fp));

	return used_math != 0;
	}
	EXPORT_SYMBOL(dump_fpu);

	/*
	* fill in the user structure for a core dump..
	*/
	void dump_thread(struct pt_regs * regs, struct user * dump)
	{
	struct task_struct *tsk = current;

	dump->magic = CMAGIC;
	dump->start_code = tsk->mm->start_code;
	dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);

	dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
	dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
	dump->u_ssize = 0;

	dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
	dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
	dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn.arm;
	dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn.arm;
	dump->u_debugreg[4] = tsk->thread.debug.nsaved;

	if (dump->start_stack < 0x04000000)
	dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;

	dump->regs = *regs;
	dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
	}
	EXPORT_SYMBOL(dump_thread);

	/*
	* Shuffle the argument into the correct register before calling the
	* thread function. r1 is the thread argument, r2 is the pointer to
	* the thread function, and r3 points to the exit function.
	*/
	extern void kernel_thread_helper(void);
	asm( ".section .text\n"
	" .align\n"
	" .type kernel_thread_helper, #function\n"
	"kernel_thread_helper:\n"
	" mov r0, r1\n"
	" mov lr, r3\n"
	" mov pc, r2\n"
	" .size kernel_thread_helper, . - kernel_thread_helper\n"
	" .previous");

	/*
	* Create a kernel thread.
	*/
	pid_t kernel_thread(int (fn)(void ), void *arg, unsigned long flags)
	{
	struct pt_regs regs;

	memset(&regs, 0, sizeof(regs));

	regs.ARM_r1 = (unsigned long)arg;
	regs.ARM_r2 = (unsigned long)fn;
	regs.ARM_r3 = (unsigned long)do_exit;
	regs.ARM_pc = (unsigned long)kernel_thread_helper;
	regs.ARM_cpsr = SVC_MODE;

	return do_fork(flags\|CLONE_VM\|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
	}
	EXPORT_SYMBOL(kernel_thread);

	unsigned long get_wchan(struct task_struct *p)
	{
	unsigned long fp, lr;
	unsigned long stack_start, stack_end;
	int count = 0;
	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	return 0;

	stack_start = (unsigned long)(p->thread_info + 1);
	stack_end = ((unsigned long)p->thread_info) + THREAD_SIZE;

	fp = thread_saved_fp(p);
	do {
	if (fp < stack_start \|\| fp > stack_end)
	return 0;
	lr = pc_pointer (((unsigned long *)fp)[-1]);
	if (!in_sched_functions(lr))
	return lr;
	fp = (unsigned long ) (fp - 12);
	} while (count ++ < 16);
	return 0;
	}
	EXPORT_SYMBOL(get_wchan);