arch/avr32/kernel/process.c - maze/linux - Git at Google

 /*
  * 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/sched.h>
 #include <linux/module.h>
 #include <linux/kallsyms.h>
 #include <linux/fs.h>
 #include <linux/ptrace.h>
 #include <linux/reboot.h>
 #include <linux/uaccess.h>
 #include <linux/unistd.h>

 #include <asm/sysreg.h>
 #include <asm/ocd.h>

 void (*pm_power_off)(void) = NULL;
 EXPORT_SYMBOL(pm_power_off);

 extern void cpu_idle_sleep(void);

 /*
  * This file handles the architecture-dependent parts of process handling..
  */

 void cpu_idle(void)
 {
 	/* endless idle loop with no priority at all */
 	while (1) {
 		while (!need_resched())
 			cpu_idle_sleep();
 		preempt_enable_no_resched();
 		schedule();
 		preempt_disable();
 	}
 }

 void machine_halt(void)
 {
 	/*
 	 * Enter Stop mode. The 32 kHz oscillator will keep running so
 	 * the RTC will keep the time properly and the system will
 	 * boot quickly.
 	 */
 	asm volatile("sleep 3\n\t"
 		     "sub pc, -2");
 }

 void machine_power_off(void)
 {
 }

 void machine_restart(char *cmd)
 {
 	__mtdr(DBGREG_DC, DC_DBE);
 	__mtdr(DBGREG_DC, DC_RES);
 	while (1) ;
 }

 /*
  * PC is actually discarded when returning from a system call -- the
  * return address must be stored in LR. This function will make sure
  * LR points to do_exit before starting the thread.
  *
  * Also, when returning from fork(), r12 is 0, so we must copy the
  * argument as well.
  *
  *  r0 : The argument to the main thread function
  *  r1 : The address of do_exit
  *  r2 : The address of the main thread function
  */
 asmlinkage extern void kernel_thread_helper(void);
 __asm__("	.type	kernel_thread_helper, @function\n"
 	"kernel_thread_helper:\n"
 	"	mov	r12, r0\n"
 	"	mov	lr, r2\n"
 	"	mov	pc, r1\n"
 	"	.size	kernel_thread_helper, . - kernel_thread_helper");

 int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 {
 	struct pt_regs regs;

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

 	regs.r0 = (unsigned long)arg;
 	regs.r1 = (unsigned long)fn;
 	regs.r2 = (unsigned long)do_exit;
 	regs.lr = (unsigned long)kernel_thread_helper;
 	regs.pc = (unsigned long)kernel_thread_helper;
 	regs.sr = MODE_SUPERVISOR;

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

 /*
  * Free current thread data structures etc
  */
 void exit_thread(void)
 {
 	/* nothing to do */
 }

 void flush_thread(void)
 {
 	/* nothing to do */
 }

 void release_thread(struct task_struct *dead_task)
 {
 	/* do nothing */
 }

 static void dump_mem(const char *str, const char *log_lvl,
 		     unsigned long bottom, unsigned long top)
 {
 	unsigned long p;
 	int i;

 	printk("%s%s(0x%08lx to 0x%08lx)\n", log_lvl, str, bottom, top);

 	for (p = bottom & ~31; p < top; ) {
 		printk("%s%04lx: ", log_lvl, p & 0xffff);

 		for (i = 0; i < 8; i++, p += 4) {
 			unsigned int val;

 			if (p < bottom || p >= top)
 				printk("         ");
 			else {
 				if (__get_user(val, (unsigned int __user *)p)) {
 					printk("\n");
 					goto out;
 				}
 				printk("%08x ", val);
 			}
 		}
 		printk("\n");
 	}

 out:
 	return;
 }

 static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
 {
 	return (p > (unsigned long)tinfo)
 		&& (p < (unsigned long)tinfo + THREAD_SIZE - 3);
 }

 #ifdef CONFIG_FRAME_POINTER
 static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
 			       struct pt_regs *regs, const char *log_lvl)
 {
 	unsigned long lr, fp;
 	struct thread_info *tinfo;

 	if (regs)
 		fp = regs->r7;
 	else if (tsk == current)
 		asm("mov %0, r7" : "=r"(fp));
 	else
 		fp = tsk->thread.cpu_context.r7;

 	/*
 	 * Walk the stack as long as the frame pointer (a) is within
 	 * the kernel stack of the task, and (b) it doesn't move
 	 * downwards.
 	 */
 	tinfo = task_thread_info(tsk);
 	printk("%sCall trace:\n", log_lvl);
 	while (valid_stack_ptr(tinfo, fp)) {
 		unsigned long new_fp;

 		lr = *(unsigned long *)fp;
 #ifdef CONFIG_KALLSYMS
 		printk("%s [<%08lx>] ", log_lvl, lr);
 #else
 		printk(" [<%08lx>] ", lr);
 #endif
 		print_symbol("%s\n", lr);

 		new_fp = *(unsigned long *)(fp + 4);
 		if (new_fp <= fp)
 			break;
 		fp = new_fp;
 	}
 	printk("\n");
 }
 #else
 static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
 			       struct pt_regs *regs, const char *log_lvl)
 {
 	unsigned long addr;

 	printk("%sCall trace:\n", log_lvl);

 	while (!kstack_end(sp)) {
 		addr = *sp++;
 		if (kernel_text_address(addr)) {
 #ifdef CONFIG_KALLSYMS
 			printk("%s [<%08lx>] ", log_lvl, addr);
 #else
 			printk(" [<%08lx>] ", addr);
 #endif
 			print_symbol("%s\n", addr);
 		}
 	}
 	printk("\n");
 }
 #endif

 void show_stack_log_lvl(struct task_struct *tsk, unsigned long sp,
 			struct pt_regs *regs, const char *log_lvl)
 {
 	struct thread_info *tinfo;

 	if (sp == 0) {
 		if (tsk)
 			sp = tsk->thread.cpu_context.ksp;
 		else
 			sp = (unsigned long)&tinfo;
 	}
 	if (!tsk)
 		tsk = current;

 	tinfo = task_thread_info(tsk);

 	if (valid_stack_ptr(tinfo, sp)) {
 		dump_mem("Stack: ", log_lvl, sp,
 			 THREAD_SIZE + (unsigned long)tinfo);
 		show_trace_log_lvl(tsk, (unsigned long *)sp, regs, log_lvl);
 	}
 }

 void show_stack(struct task_struct *tsk, unsigned long *stack)
 {
 	show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
 }

 void dump_stack(void)
 {
 	unsigned long stack;

 	show_trace_log_lvl(current, &stack, NULL, "");
 }
 EXPORT_SYMBOL(dump_stack);

 static const char *cpu_modes[] = {
 	"Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
 	"Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
 };

 void show_regs_log_lvl(struct pt_regs *regs, const char *log_lvl)
 {
 	unsigned long sp = regs->sp;
 	unsigned long lr = regs->lr;
 	unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;

 	if (!user_mode(regs)) {
 		sp = (unsigned long)regs + FRAME_SIZE_FULL;

 		printk("%s", log_lvl);
 		print_symbol("PC is at %s\n", instruction_pointer(regs));
 		printk("%s", log_lvl);
 		print_symbol("LR is at %s\n", lr);
 	}

 	printk("%spc : [<%08lx>]    lr : [<%08lx>]    %s\n"
 	       "%ssp : %08lx  r12: %08lx  r11: %08lx\n",
 	       log_lvl, instruction_pointer(regs), lr, print_tainted(),
 	       log_lvl, sp, regs->r12, regs->r11);
 	printk("%sr10: %08lx  r9 : %08lx  r8 : %08lx\n",
 	       log_lvl, regs->r10, regs->r9, regs->r8);
 	printk("%sr7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 	       log_lvl, regs->r7, regs->r6, regs->r5, regs->r4);
 	printk("%sr3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 	       log_lvl, regs->r3, regs->r2, regs->r1, regs->r0);
 	printk("%sFlags: %c%c%c%c%c\n", log_lvl,
 	       regs->sr & SR_Q ? 'Q' : 'q',
 	       regs->sr & SR_V ? 'V' : 'v',
 	       regs->sr & SR_N ? 'N' : 'n',
 	       regs->sr & SR_Z ? 'Z' : 'z',
 	       regs->sr & SR_C ? 'C' : 'c');
 	printk("%sMode bits: %c%c%c%c%c%c%c%c%c\n", log_lvl,
 	       regs->sr & SR_H ? 'H' : 'h',
 	       regs->sr & SR_R ? 'R' : 'r',
 	       regs->sr & SR_J ? 'J' : 'j',
 	       regs->sr & SR_EM ? 'E' : 'e',
 	       regs->sr & SR_I3M ? '3' : '.',
 	       regs->sr & SR_I2M ? '2' : '.',
 	       regs->sr & SR_I1M ? '1' : '.',
 	       regs->sr & SR_I0M ? '0' : '.',
 	       regs->sr & SR_GM ? 'G' : 'g');
 	printk("%sCPU Mode: %s\n", log_lvl, cpu_modes[mode]);
 	printk("%sProcess: %s [%d] (task: %p thread: %p)\n",
 	       log_lvl, current->comm, current->pid, current,
 	       task_thread_info(current));
 }

 void show_regs(struct pt_regs *regs)
 {
 	unsigned long sp = regs->sp;

 	if (!user_mode(regs))
 		sp = (unsigned long)regs + FRAME_SIZE_FULL;

 	show_regs_log_lvl(regs, "");
 	show_trace_log_lvl(current, (unsigned long *)sp, regs, "");
 }
 EXPORT_SYMBOL(show_regs);

 /* Fill in the fpu structure for a core dump. This is easy -- we don't have any */
 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 {
 	/* Not valid */
 	return 0;
 }

 asmlinkage void ret_from_fork(void);

 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 		unsigned long unused,
 		struct task_struct *p, struct pt_regs *regs)
 {
 	struct pt_regs *childregs;

 	childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)task_stack_page(p))) - 1;
 	*childregs = *regs;

 	if (user_mode(regs))
 		childregs->sp = usp;
 	else
 		childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;

 	childregs->r12 = 0; /* Set return value for child */

 	p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
 	p->thread.cpu_context.ksp = (unsigned long)childregs;
 	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;

 	return 0;
 }

 /* r12-r8 are dummy parameters to force the compiler to use the stack */
 asmlinkage int sys_fork(struct pt_regs *regs)
 {
 	return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
 }

 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 			 unsigned long parent_tidptr,
 			 unsigned long child_tidptr, struct pt_regs *regs)
 {
 	if (!newsp)
 		newsp = regs->sp;
 	return do_fork(clone_flags, newsp, regs, 0,
 		       (int __user *)parent_tidptr,
 		       (int __user *)child_tidptr);
 }

 asmlinkage int sys_vfork(struct pt_regs *regs)
 {
 	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs,
 		       0, NULL, NULL);
 }

 asmlinkage int sys_execve(char __user *ufilename, char __user *__user *uargv,
 			  char __user *__user *uenvp, struct pt_regs *regs)
 {
 	int error;
 	char *filename;

 	filename = getname(ufilename);
 	error = PTR_ERR(filename);
 	if (IS_ERR(filename))
 		goto out;

 	error = do_execve(filename, uargv, uenvp, regs);
 	if (error == 0)
 		current->ptrace &= ~PT_DTRACE;
 	putname(filename);

 out:
 	return error;
 }


 /*
  * This function is supposed to answer the question "who called
  * schedule()?"
  */
 unsigned long get_wchan(struct task_struct *p)
 {
 	unsigned long pc;
 	unsigned long stack_page;

 	if (!p || p == current || p->state == TASK_RUNNING)
 		return 0;

 	stack_page = (unsigned long)task_stack_page(p);
 	BUG_ON(!stack_page);

 	/*
 	 * The stored value of PC is either the address right after
 	 * the call to __switch_to() or ret_from_fork.
 	 */
 	pc = thread_saved_pc(p);
 	if (in_sched_functions(pc)) {
 #ifdef CONFIG_FRAME_POINTER
 		unsigned long fp = p->thread.cpu_context.r7;
 		BUG_ON(fp < stack_page || fp > (THREAD_SIZE + stack_page));
 		pc = *(unsigned long *)fp;
 #else
 		/*
 		 * We depend on the frame size of schedule here, which
 		 * is actually quite ugly. It might be possible to
 		 * determine the frame size automatically at build
 		 * time by doing this:
 		 *   - compile sched.c
 		 *   - disassemble the resulting sched.o
 		 *   - look for 'sub sp,??' shortly after '<schedule>:'
 		 */
 		unsigned long sp = p->thread.cpu_context.ksp + 16;
 		BUG_ON(sp < stack_page || sp > (THREAD_SIZE + stack_page));
 		pc = *(unsigned long *)sp;
 #endif
 	}

 	return pc;
 }
	/*
	* 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/sched.h>
	#include <linux/module.h>
	#include <linux/kallsyms.h>
	#include <linux/fs.h>
	#include <linux/ptrace.h>
	#include <linux/reboot.h>
	#include <linux/uaccess.h>
	#include <linux/unistd.h>

	#include <asm/sysreg.h>
	#include <asm/ocd.h>

	void (*pm_power_off)(void) = NULL;
	EXPORT_SYMBOL(pm_power_off);

	extern void cpu_idle_sleep(void);

	/*
	* This file handles the architecture-dependent parts of process handling..
	*/

	void cpu_idle(void)
	{
	/* endless idle loop with no priority at all */
	while (1) {
	while (!need_resched())
	cpu_idle_sleep();
	preempt_enable_no_resched();
	schedule();
	preempt_disable();
	}
	}

	void machine_halt(void)
	{
	/*
	* Enter Stop mode. The 32 kHz oscillator will keep running so
	* the RTC will keep the time properly and the system will
	* boot quickly.
	*/
	asm volatile("sleep 3\n\t"
	"sub pc, -2");
	}

	void machine_power_off(void)
	{
	}

	void machine_restart(char *cmd)
	{
	__mtdr(DBGREG_DC, DC_DBE);
	__mtdr(DBGREG_DC, DC_RES);
	while (1) ;
	}

	/*
	* PC is actually discarded when returning from a system call -- the
	* return address must be stored in LR. This function will make sure
	* LR points to do_exit before starting the thread.
	*
	* Also, when returning from fork(), r12 is 0, so we must copy the
	* argument as well.
	*
	* r0 : The argument to the main thread function
	* r1 : The address of do_exit
	* r2 : The address of the main thread function
	*/
	asmlinkage extern void kernel_thread_helper(void);
	__asm__(" .type kernel_thread_helper, @function\n"
	"kernel_thread_helper:\n"
	" mov r12, r0\n"
	" mov lr, r2\n"
	" mov pc, r1\n"
	" .size kernel_thread_helper, . - kernel_thread_helper");

	int kernel_thread(int (fn)(void ), void *arg, unsigned long flags)
	{
	struct pt_regs regs;

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

	regs.r0 = (unsigned long)arg;
	regs.r1 = (unsigned long)fn;
	regs.r2 = (unsigned long)do_exit;
	regs.lr = (unsigned long)kernel_thread_helper;
	regs.pc = (unsigned long)kernel_thread_helper;
	regs.sr = MODE_SUPERVISOR;

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

	/*
	* Free current thread data structures etc
	*/
	void exit_thread(void)
	{
	/* nothing to do */
	}

	void flush_thread(void)
	{
	/* nothing to do */
	}

	void release_thread(struct task_struct *dead_task)
	{
	/* do nothing */
	}

	static void dump_mem(const char str, const char log_lvl,
	unsigned long bottom, unsigned long top)
	{
	unsigned long p;
	int i;

	printk("%s%s(0x%08lx to 0x%08lx)\n", log_lvl, str, bottom, top);

	for (p = bottom & ~31; p < top; ) {
	printk("%s%04lx: ", log_lvl, p & 0xffff);

	for (i = 0; i < 8; i++, p += 4) {
	unsigned int val;

	if (p < bottom \|\| p >= top)
	printk(" ");
	else {
	if (__get_user(val, (unsigned int __user *)p)) {
	printk("\n");
	goto out;
	}
	printk("%08x ", val);
	}
	}
	printk("\n");
	}

	out:
	return;
	}

	static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
	{
	return (p > (unsigned long)tinfo)
	&& (p < (unsigned long)tinfo + THREAD_SIZE - 3);
	}

	#ifdef CONFIG_FRAME_POINTER
	static void show_trace_log_lvl(struct task_struct tsk, unsigned long sp,
	struct pt_regs regs, const char log_lvl)
	{
	unsigned long lr, fp;
	struct thread_info *tinfo;

	if (regs)
	fp = regs->r7;
	else if (tsk == current)
	asm("mov %0, r7" : "=r"(fp));
	else
	fp = tsk->thread.cpu_context.r7;

	/*
	* Walk the stack as long as the frame pointer (a) is within
	* the kernel stack of the task, and (b) it doesn't move
	* downwards.
	*/
	tinfo = task_thread_info(tsk);
	printk("%sCall trace:\n", log_lvl);
	while (valid_stack_ptr(tinfo, fp)) {
	unsigned long new_fp;

	lr = (unsigned long )fp;
	#ifdef CONFIG_KALLSYMS
	printk("%s [<%08lx>] ", log_lvl, lr);
	#else
	printk(" [<%08lx>] ", lr);
	#endif
	print_symbol("%s\n", lr);

	new_fp = (unsigned long )(fp + 4);
	if (new_fp <= fp)
	break;
	fp = new_fp;
	}
	printk("\n");
	}
	#else
	static void show_trace_log_lvl(struct task_struct tsk, unsigned long sp,
	struct pt_regs regs, const char log_lvl)
	{
	unsigned long addr;

	printk("%sCall trace:\n", log_lvl);

	while (!kstack_end(sp)) {
	addr = *sp++;
	if (kernel_text_address(addr)) {
	#ifdef CONFIG_KALLSYMS
	printk("%s [<%08lx>] ", log_lvl, addr);
	#else
	printk(" [<%08lx>] ", addr);
	#endif
	print_symbol("%s\n", addr);
	}
	}
	printk("\n");
	}
	#endif

	void show_stack_log_lvl(struct task_struct *tsk, unsigned long sp,
	struct pt_regs regs, const char log_lvl)
	{
	struct thread_info *tinfo;

	if (sp == 0) {
	if (tsk)
	sp = tsk->thread.cpu_context.ksp;
	else
	sp = (unsigned long)&tinfo;
	}
	if (!tsk)
	tsk = current;

	tinfo = task_thread_info(tsk);

	if (valid_stack_ptr(tinfo, sp)) {
	dump_mem("Stack: ", log_lvl, sp,
	THREAD_SIZE + (unsigned long)tinfo);
	show_trace_log_lvl(tsk, (unsigned long *)sp, regs, log_lvl);
	}
	}

	void show_stack(struct task_struct tsk, unsigned long stack)
	{
	show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
	}

	void dump_stack(void)
	{
	unsigned long stack;

	show_trace_log_lvl(current, &stack, NULL, "");
	}
	EXPORT_SYMBOL(dump_stack);

	static const char *cpu_modes[] = {
	"Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
	"Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
	};

	void show_regs_log_lvl(struct pt_regs regs, const char log_lvl)
	{
	unsigned long sp = regs->sp;
	unsigned long lr = regs->lr;
	unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;

	if (!user_mode(regs)) {
	sp = (unsigned long)regs + FRAME_SIZE_FULL;

	printk("%s", log_lvl);
	print_symbol("PC is at %s\n", instruction_pointer(regs));
	printk("%s", log_lvl);
	print_symbol("LR is at %s\n", lr);
	}

	printk("%spc : [<%08lx>] lr : [<%08lx>] %s\n"
	"%ssp : %08lx r12: %08lx r11: %08lx\n",
	log_lvl, instruction_pointer(regs), lr, print_tainted(),
	log_lvl, sp, regs->r12, regs->r11);
	printk("%sr10: %08lx r9 : %08lx r8 : %08lx\n",
	log_lvl, regs->r10, regs->r9, regs->r8);
	printk("%sr7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
	log_lvl, regs->r7, regs->r6, regs->r5, regs->r4);
	printk("%sr3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
	log_lvl, regs->r3, regs->r2, regs->r1, regs->r0);
	printk("%sFlags: %c%c%c%c%c\n", log_lvl,
	regs->sr & SR_Q ? 'Q' : 'q',
	regs->sr & SR_V ? 'V' : 'v',
	regs->sr & SR_N ? 'N' : 'n',
	regs->sr & SR_Z ? 'Z' : 'z',
	regs->sr & SR_C ? 'C' : 'c');
	printk("%sMode bits: %c%c%c%c%c%c%c%c%c\n", log_lvl,
	regs->sr & SR_H ? 'H' : 'h',
	regs->sr & SR_R ? 'R' : 'r',
	regs->sr & SR_J ? 'J' : 'j',
	regs->sr & SR_EM ? 'E' : 'e',
	regs->sr & SR_I3M ? '3' : '.',
	regs->sr & SR_I2M ? '2' : '.',
	regs->sr & SR_I1M ? '1' : '.',
	regs->sr & SR_I0M ? '0' : '.',
	regs->sr & SR_GM ? 'G' : 'g');
	printk("%sCPU Mode: %s\n", log_lvl, cpu_modes[mode]);
	printk("%sProcess: %s [%d] (task: %p thread: %p)\n",
	log_lvl, current->comm, current->pid, current,
	task_thread_info(current));
	}

	void show_regs(struct pt_regs *regs)
	{
	unsigned long sp = regs->sp;

	if (!user_mode(regs))
	sp = (unsigned long)regs + FRAME_SIZE_FULL;

	show_regs_log_lvl(regs, "");
	show_trace_log_lvl(current, (unsigned long *)sp, regs, "");
	}
	EXPORT_SYMBOL(show_regs);

	/* Fill in the fpu structure for a core dump. This is easy -- we don't have any */
	int dump_fpu(struct pt_regs regs, elf_fpregset_t fpu)
	{
	/* Not valid */
	return 0;
	}

	asmlinkage void ret_from_fork(void);

	int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
	unsigned long unused,
	struct task_struct p, struct pt_regs regs)
	{
	struct pt_regs *childregs;

	childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)task_stack_page(p))) - 1;
	childregs = regs;

	if (user_mode(regs))
	childregs->sp = usp;
	else
	childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;

	childregs->r12 = 0; /* Set return value for child */

	p->thread.cpu_context.sr = MODE_SUPERVISOR \| SR_GM;
	p->thread.cpu_context.ksp = (unsigned long)childregs;
	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;

	return 0;
	}

	/* r12-r8 are dummy parameters to force the compiler to use the stack */
	asmlinkage int sys_fork(struct pt_regs *regs)
	{
	return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
	}

	asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
	unsigned long parent_tidptr,
	unsigned long child_tidptr, struct pt_regs *regs)
	{
	if (!newsp)
	newsp = regs->sp;
	return do_fork(clone_flags, newsp, regs, 0,
	(int __user *)parent_tidptr,
	(int __user *)child_tidptr);
	}

	asmlinkage int sys_vfork(struct pt_regs *regs)
	{
	return do_fork(CLONE_VFORK \| CLONE_VM \| SIGCHLD, regs->sp, regs,
	0, NULL, NULL);
	}

	asmlinkage int sys_execve(char __user ufilename, char __user __user *uargv,
	char __user __user uenvp, struct pt_regs *regs)
	{
	int error;
	char *filename;

	filename = getname(ufilename);
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
	goto out;

	error = do_execve(filename, uargv, uenvp, regs);
	if (error == 0)
	current->ptrace &= ~PT_DTRACE;
	putname(filename);

	out:
	return error;
	}


	/*
	* This function is supposed to answer the question "who called
	* schedule()?"
	*/
	unsigned long get_wchan(struct task_struct *p)
	{
	unsigned long pc;
	unsigned long stack_page;

	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	return 0;

	stack_page = (unsigned long)task_stack_page(p);
	BUG_ON(!stack_page);

	/*
	* The stored value of PC is either the address right after
	* the call to __switch_to() or ret_from_fork.
	*/
	pc = thread_saved_pc(p);
	if (in_sched_functions(pc)) {
	#ifdef CONFIG_FRAME_POINTER
	unsigned long fp = p->thread.cpu_context.r7;
	BUG_ON(fp < stack_page \|\| fp > (THREAD_SIZE + stack_page));
	pc = (unsigned long )fp;
	#else
	/*
	* We depend on the frame size of schedule here, which
	* is actually quite ugly. It might be possible to
	* determine the frame size automatically at build
	* time by doing this:
	* - compile sched.c
	* - disassemble the resulting sched.o
	* - look for 'sub sp,??' shortly after '<schedule>:'
	*/
	unsigned long sp = p->thread.cpu_context.ksp + 16;
	BUG_ON(sp < stack_page \|\| sp > (THREAD_SIZE + stack_page));
	pc = (unsigned long )sp;
	#endif
	}

	return pc;
	}