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

 /* $Id: process.c,v 1.28 2004/05/05 16:54:23 lethal Exp $
  *
  *  linux/arch/sh/kernel/process.c
  *
  *  Copyright (C) 1995  Linus Torvalds
  *
  *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
  */

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

 #include <linux/module.h>
 #include <linux/unistd.h>
 #include <linux/mm.h>
 #include <linux/elfcore.h>
 #include <linux/a.out.h>
 #include <linux/slab.h>
 #include <linux/pm.h>
 #include <linux/ptrace.h>
 #include <linux/kallsyms.h>
 #include <linux/kexec.h>

 #include <asm/io.h>
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
 #include <asm/elf.h>
 #include <asm/ubc.h>

 static int hlt_counter=0;

 int ubc_usercnt = 0;

 #define HARD_IDLE_TIMEOUT (HZ / 3)

 void (*pm_idle)(void);

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

 void disable_hlt(void)
 {
 	hlt_counter++;
 }

 EXPORT_SYMBOL(disable_hlt);

 void enable_hlt(void)
 {
 	hlt_counter--;
 }

 EXPORT_SYMBOL(enable_hlt);

 void default_idle(void)
 {
 	if (!hlt_counter)
 		cpu_sleep();
 	else
 		cpu_relax();
 }

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

 		if (!idle)
 			idle = default_idle;

 		while (!need_resched())
 			idle();

 		preempt_enable_no_resched();
 		schedule();
 		preempt_disable();
 	}
 }

 void machine_restart(char * __unused)
 {
 	/* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
 	asm volatile("ldc %0, sr\n\t"
 		     "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
 }

 void machine_halt(void)
 {
 	local_irq_disable();

 	while (1)
 		cpu_sleep();
 }

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

 void show_regs(struct pt_regs * regs)
 {
 	printk("\n");
 	printk("Pid : %d, Comm: %20s\n", current->pid, current->comm);
 	print_symbol("PC is at %s\n", regs->pc);
 	printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
 	       regs->pc, regs->regs[15], regs->sr);
 #ifdef CONFIG_MMU
 	printk("TEA : %08x    ", ctrl_inl(MMU_TEA));
 #else
 	printk("                  ");
 #endif
 	printk("%s\n", print_tainted());

 	printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
 	       regs->regs[0],regs->regs[1],
 	       regs->regs[2],regs->regs[3]);
 	printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
 	       regs->regs[4],regs->regs[5],
 	       regs->regs[6],regs->regs[7]);
 	printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
 	       regs->regs[8],regs->regs[9],
 	       regs->regs[10],regs->regs[11]);
 	printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
 	       regs->regs[12],regs->regs[13],
 	       regs->regs[14]);
 	printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
 	       regs->mach, regs->macl, regs->gbr, regs->pr);

 	/*
 	 * If we're in kernel mode, dump the stack too..
 	 */
 	if (!user_mode(regs)) {
 		extern void show_task(unsigned long *sp);
 		unsigned long sp = regs->regs[15];

 		show_task((unsigned long *)sp);
 	}
 }

 /*
  * Create a kernel thread
  */

 /*
  * This is the mechanism for creating a new kernel thread.
  *
  */
 extern void kernel_thread_helper(void);
 __asm__(".align 5\n"
 	"kernel_thread_helper:\n\t"
 	"jsr	@r5\n\t"
 	" nop\n\t"
 	"mov.l	1f, r1\n\t"
 	"jsr	@r1\n\t"
 	" mov	r0, r4\n\t"
 	".align 2\n\t"
 	"1:.long do_exit");

 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 {	/* Don't use this in BL=1(cli).  Or else, CPU resets! */
 	struct pt_regs regs;

 	memset(&regs, 0, sizeof(regs));
 	regs.regs[4] = (unsigned long) arg;
 	regs.regs[5] = (unsigned long) fn;

 	regs.pc = (unsigned long) kernel_thread_helper;
 	regs.sr = (1 << 30);

 	/* Ok, create the new process.. */
 	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 }

 /*
  * Free current thread data structures etc..
  */
 void exit_thread(void)
 {
 	if (current->thread.ubc_pc) {
 		current->thread.ubc_pc = 0;
 		ubc_usercnt -= 1;
 	}
 }

 void flush_thread(void)
 {
 #if defined(CONFIG_SH_FPU)
 	struct task_struct *tsk = current;
 	/* Forget lazy FPU state */
 	clear_fpu(tsk, task_pt_regs(tsk));
 	clear_used_math();
 #endif
 }

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

 /* Fill in the fpu structure for a core dump.. */
 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 {
 	int fpvalid = 0;

 #if defined(CONFIG_SH_FPU)
 	struct task_struct *tsk = current;

 	fpvalid = !!tsk_used_math(tsk);
 	if (fpvalid) {
 		unlazy_fpu(tsk, regs);
 		memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
 	}
 #endif

 	return fpvalid;
 }

 /*
  * Capture the user space registers if the task is not running (in user space)
  */
 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
 {
 	struct pt_regs ptregs;

 	ptregs = *task_pt_regs(tsk);
 	elf_core_copy_regs(regs, &ptregs);

 	return 1;
 }

 int
 dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *fpu)
 {
 	int fpvalid = 0;

 #if defined(CONFIG_SH_FPU)
 	fpvalid = !!tsk_used_math(tsk);
 	if (fpvalid) {
 		unlazy_fpu(tsk, task_pt_regs(tsk));
 		memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
 	}
 #endif

 	return fpvalid;
 }

 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 thread_info *ti = task_thread_info(p);
 	struct pt_regs *childregs;
 #if defined(CONFIG_SH_FPU)
 	struct task_struct *tsk = current;

 	unlazy_fpu(tsk, regs);
 	p->thread.fpu = tsk->thread.fpu;
 	copy_to_stopped_child_used_math(p);
 #endif

 	childregs = task_pt_regs(p);
 	*childregs = *regs;

 	if (user_mode(regs)) {
 		childregs->regs[15] = usp;
 		ti->addr_limit = USER_DS;
 	} else {
 		childregs->regs[15] = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 		ti->addr_limit = KERNEL_DS;
 	}
         if (clone_flags & CLONE_SETTLS) {
 		childregs->gbr = childregs->regs[0];
 	}
 	childregs->regs[0] = 0; /* Set return value for child */

 	p->thread.sp = (unsigned long) childregs;
 	p->thread.pc = (unsigned long) ret_from_fork;

 	p->thread.ubc_pc = 0;

 	return 0;
 }

 /* Tracing by user break controller.  */
 static void
 ubc_set_tracing(int asid, unsigned long pc)
 {
 	ctrl_outl(pc, UBC_BARA);

 #ifdef CONFIG_MMU
 	/* We don't have any ASID settings for the SH-2! */
 	if (cpu_data->type != CPU_SH7604)
 		ctrl_outb(asid, UBC_BASRA);
 #endif

 	ctrl_outl(0, UBC_BAMRA);

 	if (cpu_data->type == CPU_SH7729 || cpu_data->type == CPU_SH7710) {
 		ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
 		ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
 	} else {
 		ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
 		ctrl_outw(BRCR_PCBA, UBC_BRCR);
 	}
 }

 /*
  *	switch_to(x,y) should switch tasks from x to y.
  *
  */
 struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next)
 {
 #if defined(CONFIG_SH_FPU)
 	unlazy_fpu(prev, task_pt_regs(prev));
 #endif

 #ifdef CONFIG_PREEMPT
 	{
 		unsigned long flags;
 		struct pt_regs *regs;

 		local_irq_save(flags);
 		regs = task_pt_regs(prev);
 		if (user_mode(regs) && regs->regs[15] >= 0xc0000000) {
 			int offset = (int)regs->regs[15];

 			/* Reset stack pointer: clear critical region mark */
 			regs->regs[15] = regs->regs[1];
 			if (regs->pc < regs->regs[0])
 				/* Go to rewind point */
 				regs->pc = regs->regs[0] + offset;
 		}
 		local_irq_restore(flags);
 	}
 #endif

 #ifdef CONFIG_MMU
 	/*
 	 * Restore the kernel mode register
 	 *   	k7 (r7_bank1)
 	 */
 	asm volatile("ldc	%0, r7_bank"
 		     : /* no output */
 		     : "r" (task_thread_info(next)));
 #endif

 	/* If no tasks are using the UBC, we're done */
 	if (ubc_usercnt == 0)
 		/* If no tasks are using the UBC, we're done */;
 	else if (next->thread.ubc_pc && next->mm) {
 		int asid = 0;
 #ifdef CONFIG_MMU
 		asid |= next->mm->context.id & MMU_CONTEXT_ASID_MASK;
 #endif
 		ubc_set_tracing(asid, next->thread.ubc_pc);
 	} else {
 		ctrl_outw(0, UBC_BBRA);
 		ctrl_outw(0, UBC_BBRB);
 	}

 	return prev;
 }

 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
 			unsigned long r6, unsigned long r7,
 			struct pt_regs regs)
 {
 #ifdef CONFIG_MMU
 	return do_fork(SIGCHLD, regs.regs[15], &regs, 0, NULL, NULL);
 #else
 	/* fork almost works, enough to trick you into looking elsewhere :-( */
 	return -EINVAL;
 #endif
 }

 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.regs[15];
 	return do_fork(clone_flags, newsp, &regs, 0,
 			(int __user *)parent_tidptr, (int __user *)child_tidptr);
 }

 /*
  * This is trivial, and on the face of it looks like it
  * could equally well be done in user mode.
  *
  * Not so, for quite unobvious reasons - register pressure.
  * In user mode vfork() cannot have a stack frame, and if
  * done by calling the "clone()" system call directly, you
  * do not have enough call-clobbered registers to hold all
  * the information you need.
  */
 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 			 unsigned long r6, unsigned long r7,
 			 struct pt_regs regs)
 {
 	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.regs[15], &regs,
 		       0, NULL, NULL);
 }

 /*
  * sys_execve() executes a new program.
  */
 asmlinkage int sys_execve(char *ufilename, char **uargv,
 			  char **uenvp, unsigned long r7,
 			  struct pt_regs regs)
 {
 	int error;
 	char *filename;

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

 	error = do_execve(filename,
 			  (char __user * __user *)uargv,
 			  (char __user * __user *)uenvp,
 			  &regs);
 	if (error == 0) {
 		task_lock(current);
 		current->ptrace &= ~PT_DTRACE;
 		task_unlock(current);
 	}
 	putname(filename);
 out:
 	return error;
 }

 unsigned long get_wchan(struct task_struct *p)
 {
 	unsigned long schedule_frame;
 	unsigned long pc;

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

 	/*
 	 * The same comment as on the Alpha applies here, too ...
 	 */
 	pc = thread_saved_pc(p);
 	if (in_sched_functions(pc)) {
 		schedule_frame = ((unsigned long *)(long)p->thread.sp)[1];
 		return (unsigned long)((unsigned long *)schedule_frame)[1];
 	}
 	return pc;
 }

 asmlinkage void break_point_trap(unsigned long r4, unsigned long r5,
 				 unsigned long r6, unsigned long r7,
 				 struct pt_regs regs)
 {
 	/* Clear tracing.  */
 	ctrl_outw(0, UBC_BBRA);
 	ctrl_outw(0, UBC_BBRB);
 	current->thread.ubc_pc = 0;
 	ubc_usercnt -= 1;

 	force_sig(SIGTRAP, current);
 }

 asmlinkage void break_point_trap_software(unsigned long r4, unsigned long r5,
 					  unsigned long r6, unsigned long r7,
 					  struct pt_regs regs)
 {
 	regs.pc -= 2;
 	force_sig(SIGTRAP, current);
 }
	/* $Id: process.c,v 1.28 2004/05/05 16:54:23 lethal Exp $
	*
	* linux/arch/sh/kernel/process.c
	*
	* Copyright (C) 1995 Linus Torvalds
	*
	* SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
	*/

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

	#include <linux/module.h>
	#include <linux/unistd.h>
	#include <linux/mm.h>
	#include <linux/elfcore.h>
	#include <linux/a.out.h>
	#include <linux/slab.h>
	#include <linux/pm.h>
	#include <linux/ptrace.h>
	#include <linux/kallsyms.h>
	#include <linux/kexec.h>

	#include <asm/io.h>
	#include <asm/uaccess.h>
	#include <asm/mmu_context.h>
	#include <asm/elf.h>
	#include <asm/ubc.h>

	static int hlt_counter=0;

	int ubc_usercnt = 0;

	#define HARD_IDLE_TIMEOUT (HZ / 3)

	void (*pm_idle)(void);

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

	void disable_hlt(void)
	{
	hlt_counter++;
	}

	EXPORT_SYMBOL(disable_hlt);

	void enable_hlt(void)
	{
	hlt_counter--;
	}

	EXPORT_SYMBOL(enable_hlt);

	void default_idle(void)
	{
	if (!hlt_counter)
	cpu_sleep();
	else
	cpu_relax();
	}

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

	if (!idle)
	idle = default_idle;

	while (!need_resched())
	idle();

	preempt_enable_no_resched();
	schedule();
	preempt_disable();
	}
	}

	void machine_restart(char * __unused)
	{
	/* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
	asm volatile("ldc %0, sr\n\t"
	"mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
	}

	void machine_halt(void)
	{
	local_irq_disable();

	while (1)
	cpu_sleep();
	}

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

	void show_regs(struct pt_regs * regs)
	{
	printk("\n");
	printk("Pid : %d, Comm: %20s\n", current->pid, current->comm);
	print_symbol("PC is at %s\n", regs->pc);
	printk("PC : %08lx SP : %08lx SR : %08lx ",
	regs->pc, regs->regs[15], regs->sr);
	#ifdef CONFIG_MMU
	printk("TEA : %08x ", ctrl_inl(MMU_TEA));
	#else
	printk(" ");
	#endif
	printk("%s\n", print_tainted());

	printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n",
	regs->regs[0],regs->regs[1],
	regs->regs[2],regs->regs[3]);
	printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n",
	regs->regs[4],regs->regs[5],
	regs->regs[6],regs->regs[7]);
	printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n",
	regs->regs[8],regs->regs[9],
	regs->regs[10],regs->regs[11]);
	printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
	regs->regs[12],regs->regs[13],
	regs->regs[14]);
	printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n",
	regs->mach, regs->macl, regs->gbr, regs->pr);

	/*
	* If we're in kernel mode, dump the stack too..
	*/
	if (!user_mode(regs)) {
	extern void show_task(unsigned long *sp);
	unsigned long sp = regs->regs[15];

	show_task((unsigned long *)sp);
	}
	}

	/*
	* Create a kernel thread
	*/

	/*
	* This is the mechanism for creating a new kernel thread.
	*
	*/
	extern void kernel_thread_helper(void);
	__asm__(".align 5\n"
	"kernel_thread_helper:\n\t"
	"jsr @r5\n\t"
	" nop\n\t"
	"mov.l 1f, r1\n\t"
	"jsr @r1\n\t"
	" mov r0, r4\n\t"
	".align 2\n\t"
	"1:.long do_exit");

	int kernel_thread(int (fn)(void ), void * arg, unsigned long flags)
	{ /* Don't use this in BL=1(cli). Or else, CPU resets! */
	struct pt_regs regs;

	memset(&regs, 0, sizeof(regs));
	regs.regs[4] = (unsigned long) arg;
	regs.regs[5] = (unsigned long) fn;

	regs.pc = (unsigned long) kernel_thread_helper;
	regs.sr = (1 << 30);

	/* Ok, create the new process.. */
	return do_fork(flags \| CLONE_VM \| CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
	}

	/*
	* Free current thread data structures etc..
	*/
	void exit_thread(void)
	{
	if (current->thread.ubc_pc) {
	current->thread.ubc_pc = 0;
	ubc_usercnt -= 1;
	}
	}

	void flush_thread(void)
	{
	#if defined(CONFIG_SH_FPU)
	struct task_struct *tsk = current;
	/* Forget lazy FPU state */
	clear_fpu(tsk, task_pt_regs(tsk));
	clear_used_math();
	#endif
	}

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

	/* Fill in the fpu structure for a core dump.. */
	int dump_fpu(struct pt_regs regs, elf_fpregset_t fpu)
	{
	int fpvalid = 0;

	#if defined(CONFIG_SH_FPU)
	struct task_struct *tsk = current;

	fpvalid = !!tsk_used_math(tsk);
	if (fpvalid) {
	unlazy_fpu(tsk, regs);
	memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
	}
	#endif

	return fpvalid;
	}

	/*
	* Capture the user space registers if the task is not running (in user space)
	*/
	int dump_task_regs(struct task_struct tsk, elf_gregset_t regs)
	{
	struct pt_regs ptregs;

	ptregs = *task_pt_regs(tsk);
	elf_core_copy_regs(regs, &ptregs);

	return 1;
	}

	int
	dump_task_fpu (struct task_struct tsk, elf_fpregset_t fpu)
	{
	int fpvalid = 0;

	#if defined(CONFIG_SH_FPU)
	fpvalid = !!tsk_used_math(tsk);
	if (fpvalid) {
	unlazy_fpu(tsk, task_pt_regs(tsk));
	memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
	}
	#endif

	return fpvalid;
	}

	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 thread_info *ti = task_thread_info(p);
	struct pt_regs *childregs;
	#if defined(CONFIG_SH_FPU)
	struct task_struct *tsk = current;

	unlazy_fpu(tsk, regs);
	p->thread.fpu = tsk->thread.fpu;
	copy_to_stopped_child_used_math(p);
	#endif

	childregs = task_pt_regs(p);
	childregs = regs;

	if (user_mode(regs)) {
	childregs->regs[15] = usp;
	ti->addr_limit = USER_DS;
	} else {
	childregs->regs[15] = (unsigned long)task_stack_page(p) + THREAD_SIZE;
	ti->addr_limit = KERNEL_DS;
	}
	if (clone_flags & CLONE_SETTLS) {
	childregs->gbr = childregs->regs[0];
	}
	childregs->regs[0] = 0; /* Set return value for child */

	p->thread.sp = (unsigned long) childregs;
	p->thread.pc = (unsigned long) ret_from_fork;

	p->thread.ubc_pc = 0;

	return 0;
	}

	/* Tracing by user break controller. */
	static void
	ubc_set_tracing(int asid, unsigned long pc)
	{
	ctrl_outl(pc, UBC_BARA);

	#ifdef CONFIG_MMU
	/* We don't have any ASID settings for the SH-2! */
	if (cpu_data->type != CPU_SH7604)
	ctrl_outb(asid, UBC_BASRA);
	#endif

	ctrl_outl(0, UBC_BAMRA);

	if (cpu_data->type == CPU_SH7729 \|\| cpu_data->type == CPU_SH7710) {
	ctrl_outw(BBR_INST \| BBR_READ \| BBR_CPU, UBC_BBRA);
	ctrl_outl(BRCR_PCBA \| BRCR_PCTE, UBC_BRCR);
	} else {
	ctrl_outw(BBR_INST \| BBR_READ, UBC_BBRA);
	ctrl_outw(BRCR_PCBA, UBC_BRCR);
	}
	}

	/*
	* switch_to(x,y) should switch tasks from x to y.
	*
	*/
	struct task_struct __switch_to(struct task_struct prev, struct task_struct *next)
	{
	#if defined(CONFIG_SH_FPU)
	unlazy_fpu(prev, task_pt_regs(prev));
	#endif

	#ifdef CONFIG_PREEMPT
	{
	unsigned long flags;
	struct pt_regs *regs;

	local_irq_save(flags);
	regs = task_pt_regs(prev);
	if (user_mode(regs) && regs->regs[15] >= 0xc0000000) {
	int offset = (int)regs->regs[15];

	/* Reset stack pointer: clear critical region mark */
	regs->regs[15] = regs->regs[1];
	if (regs->pc < regs->regs[0])
	/* Go to rewind point */
	regs->pc = regs->regs[0] + offset;
	}
	local_irq_restore(flags);
	}
	#endif

	#ifdef CONFIG_MMU
	/*
	* Restore the kernel mode register
	* k7 (r7_bank1)
	*/
	asm volatile("ldc %0, r7_bank"
	: /* no output */
	: "r" (task_thread_info(next)));
	#endif

	/* If no tasks are using the UBC, we're done */
	if (ubc_usercnt == 0)
	/* If no tasks are using the UBC, we're done */;
	else if (next->thread.ubc_pc && next->mm) {
	int asid = 0;
	#ifdef CONFIG_MMU
	asid \|= next->mm->context.id & MMU_CONTEXT_ASID_MASK;
	#endif
	ubc_set_tracing(asid, next->thread.ubc_pc);
	} else {
	ctrl_outw(0, UBC_BBRA);
	ctrl_outw(0, UBC_BBRB);
	}

	return prev;
	}

	asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
	unsigned long r6, unsigned long r7,
	struct pt_regs regs)
	{
	#ifdef CONFIG_MMU
	return do_fork(SIGCHLD, regs.regs[15], &regs, 0, NULL, NULL);
	#else
	/* fork almost works, enough to trick you into looking elsewhere :-( */
	return -EINVAL;
	#endif
	}

	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.regs[15];
	return do_fork(clone_flags, newsp, &regs, 0,
	(int __user )parent_tidptr, (int __user )child_tidptr);
	}

	/*
	* This is trivial, and on the face of it looks like it
	* could equally well be done in user mode.
	*
	* Not so, for quite unobvious reasons - register pressure.
	* In user mode vfork() cannot have a stack frame, and if
	* done by calling the "clone()" system call directly, you
	* do not have enough call-clobbered registers to hold all
	* the information you need.
	*/
	asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
	unsigned long r6, unsigned long r7,
	struct pt_regs regs)
	{
	return do_fork(CLONE_VFORK \| CLONE_VM \| SIGCHLD, regs.regs[15], &regs,
	0, NULL, NULL);
	}

	/*
	* sys_execve() executes a new program.
	*/
	asmlinkage int sys_execve(char ufilename, char *uargv,
	char **uenvp, unsigned long r7,
	struct pt_regs regs)
	{
	int error;
	char *filename;

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

	error = do_execve(filename,
	(char __user * __user *)uargv,
	(char __user * __user *)uenvp,
	&regs);
	if (error == 0) {
	task_lock(current);
	current->ptrace &= ~PT_DTRACE;
	task_unlock(current);
	}
	putname(filename);
	out:
	return error;
	}

	unsigned long get_wchan(struct task_struct *p)
	{
	unsigned long schedule_frame;
	unsigned long pc;

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

	/*
	* The same comment as on the Alpha applies here, too ...
	*/
	pc = thread_saved_pc(p);
	if (in_sched_functions(pc)) {
	schedule_frame = ((unsigned long *)(long)p->thread.sp)[1];
	return (unsigned long)((unsigned long *)schedule_frame)[1];
	}
	return pc;
	}

	asmlinkage void break_point_trap(unsigned long r4, unsigned long r5,
	unsigned long r6, unsigned long r7,
	struct pt_regs regs)
	{
	/* Clear tracing. */
	ctrl_outw(0, UBC_BBRA);
	ctrl_outw(0, UBC_BBRB);
	current->thread.ubc_pc = 0;
	ubc_usercnt -= 1;

	force_sig(SIGTRAP, current);
	}

	asmlinkage void break_point_trap_software(unsigned long r4, unsigned long r5,
	unsigned long r6, unsigned long r7,
	struct pt_regs regs)
	{
	regs.pc -= 2;
	force_sig(SIGTRAP, current);
	}