arch/sh/kernel/process_32.c - arm/linux - Git at Google

 /*
  * arch/sh/kernel/process.c
  *
  * This file handles the architecture-dependent parts of process handling..
  *
  *  Copyright (C) 1995  Linus Torvalds
  *
  *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
  *		     Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC
  *		     Copyright (C) 2002 - 2008  Paul Mundt
  *
  * 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/mm.h>
 #include <linux/elfcore.h>
 #include <linux/pm.h>
 #include <linux/kallsyms.h>
 #include <linux/kexec.h>
 #include <linux/kdebug.h>
 #include <linux/tick.h>
 #include <linux/reboot.h>
 #include <linux/fs.h>
 #include <linux/preempt.h>
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
 #include <asm/pgalloc.h>
 #include <asm/system.h>
 #include <asm/ubc.h>
 #include <asm/fpu.h>
 #include <asm/syscalls.h>

 static int hlt_counter;
 int ubc_usercnt = 0;

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

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

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

 static void default_idle(void)
 {
 	if (!hlt_counter) {
 		clear_thread_flag(TIF_POLLING_NRFLAG);
 		smp_mb__after_clear_bit();
 		set_bl_bit();
 		while (!need_resched())
 			cpu_sleep();
 		clear_bl_bit();
 		set_thread_flag(TIF_POLLING_NRFLAG);
 	} else
 		while (!need_resched())
 			cpu_relax();
 }

 void cpu_idle(void)
 {
 	set_thread_flag(TIF_POLLING_NRFLAG);

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

 		if (!idle)
 			idle = default_idle;

 		tick_nohz_stop_sched_tick(1);
 		while (!need_resched())
 			idle();
 		tick_nohz_restart_sched_tick();

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

 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", task_pid_nr(current), current->comm);
 	printk("CPU : %d    %s  (%s %.*s)\n",
 	       smp_processor_id(), print_tainted(), init_utsname()->release,
 	       (int)strcspn(init_utsname()->version, " "),
 	       init_utsname()->version);

 	print_symbol("PC is at %s\n", instruction_pointer(regs));
 	print_symbol("PR is at %s\n", regs->pr);

 	printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
 	       regs->pc, regs->regs[15], regs->sr);
 #ifdef CONFIG_MMU
 	printk("TEA : %08x\n", ctrl_inl(MMU_TEA));
 #else
 	printk("\n");
 #endif

 	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);

 	show_trace(NULL, (unsigned long *)regs->regs[15], regs);
 }

 /*
  * 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");

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

 	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.. */
 	pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
 		      &regs, 0, NULL, NULL);

 	trace_mark(kernel_arch_kthread_create, "pid %d fn %p", pid, fn);

 	return pid;
 }

 /*
  * 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)
 		fpvalid = !fpregs_get(tsk, NULL, 0,
 				      sizeof(struct user_fpu_struct),
 				      fpu, NULL);
 #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)childregs;
 		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)
 {
 #if defined(CONFIG_CPU_SH4A)
 	unsigned long val;

 	val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE);
 	val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid));

 	ctrl_outl(val, UBC_CBR0);
 	ctrl_outl(pc,  UBC_CAR0);
 	ctrl_outl(0x0, UBC_CAMR0);
 	ctrl_outl(0x0, UBC_CBCR);

 	val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE);
 	ctrl_outl(val, UBC_CRR0);

 	/* Read UBC register that we wrote last, for checking update */
 	val = ctrl_inl(UBC_CRR0);

 #else	/* CONFIG_CPU_SH4A */
 	ctrl_outl(pc, UBC_BARA);

 #ifdef CONFIG_MMU
 	ctrl_outb(asid, UBC_BASRA);
 #endif

 	ctrl_outl(0, UBC_BAMRA);

 	if (current_cpu_data.type == CPU_SH7729 ||
 	    current_cpu_data.type == CPU_SH7710 ||
 	    current_cpu_data.type == CPU_SH7712) {
 		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);
 	}
 #endif	/* CONFIG_CPU_SH4A */
 }

 /*
  *	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_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 |= cpu_asid(smp_processor_id(), next->mm);
 #endif
 		ubc_set_tracing(asid, next->thread.ubc_pc);
 	} else {
 #if defined(CONFIG_CPU_SH4A)
 		ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 		ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 #else
 		ctrl_outw(0, UBC_BBRA);
 		ctrl_outw(0, UBC_BBRB);
 #endif
 	}

 	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
 	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 	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)
 {
 	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 	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)
 {
 	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 	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 __user *ufilename, char __user * __user *uargv,
 			  char __user * __user *uenvp, unsigned long r7,
 			  struct pt_regs __regs)
 {
 	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 	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) {
 		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 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);

 #ifdef CONFIG_FRAME_POINTER
 	if (in_sched_functions(pc)) {
 		unsigned long schedule_frame = (unsigned long)p->thread.sp;
 		return ((unsigned long *)schedule_frame)[21];
 	}
 #endif

 	return pc;
 }

 asmlinkage void break_point_trap(void)
 {
 	/* Clear tracing.  */
 #if defined(CONFIG_CPU_SH4A)
 	ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
 	ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
 #else
 	ctrl_outw(0, UBC_BBRA);
 	ctrl_outw(0, UBC_BBRB);
 #endif
 	current->thread.ubc_pc = 0;
 	ubc_usercnt -= 1;

 	force_sig(SIGTRAP, current);
 }
	/*
	* arch/sh/kernel/process.c
	*
	* This file handles the architecture-dependent parts of process handling..
	*
	* Copyright (C) 1995 Linus Torvalds
	*
	* SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
	* Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC
	* Copyright (C) 2002 - 2008 Paul Mundt
	*
	* 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/mm.h>
	#include <linux/elfcore.h>
	#include <linux/pm.h>
	#include <linux/kallsyms.h>
	#include <linux/kexec.h>
	#include <linux/kdebug.h>
	#include <linux/tick.h>
	#include <linux/reboot.h>
	#include <linux/fs.h>
	#include <linux/preempt.h>
	#include <asm/uaccess.h>
	#include <asm/mmu_context.h>
	#include <asm/pgalloc.h>
	#include <asm/system.h>
	#include <asm/ubc.h>
	#include <asm/fpu.h>
	#include <asm/syscalls.h>

	static int hlt_counter;
	int ubc_usercnt = 0;

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

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

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

	static void default_idle(void)
	{
	if (!hlt_counter) {
	clear_thread_flag(TIF_POLLING_NRFLAG);
	smp_mb__after_clear_bit();
	set_bl_bit();
	while (!need_resched())
	cpu_sleep();
	clear_bl_bit();
	set_thread_flag(TIF_POLLING_NRFLAG);
	} else
	while (!need_resched())
	cpu_relax();
	}

	void cpu_idle(void)
	{
	set_thread_flag(TIF_POLLING_NRFLAG);

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

	if (!idle)
	idle = default_idle;

	tick_nohz_stop_sched_tick(1);
	while (!need_resched())
	idle();
	tick_nohz_restart_sched_tick();

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

	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", task_pid_nr(current), current->comm);
	printk("CPU : %d %s (%s %.*s)\n",
	smp_processor_id(), print_tainted(), init_utsname()->release,
	(int)strcspn(init_utsname()->version, " "),
	init_utsname()->version);

	print_symbol("PC is at %s\n", instruction_pointer(regs));
	print_symbol("PR is at %s\n", regs->pr);

	printk("PC : %08lx SP : %08lx SR : %08lx ",
	regs->pc, regs->regs[15], regs->sr);
	#ifdef CONFIG_MMU
	printk("TEA : %08x\n", ctrl_inl(MMU_TEA));
	#else
	printk("\n");
	#endif

	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);

	show_trace(NULL, (unsigned long *)regs->regs[15], regs);
	}

	/*
	* 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");

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

	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.. */
	pid = do_fork(flags \| CLONE_VM \| CLONE_UNTRACED, 0,
	&regs, 0, NULL, NULL);

	trace_mark(kernel_arch_kthread_create, "pid %d fn %p", pid, fn);

	return pid;
	}

	/*
	* 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)
	fpvalid = !fpregs_get(tsk, NULL, 0,
	sizeof(struct user_fpu_struct),
	fpu, NULL);
	#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)childregs;
	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)
	{
	#if defined(CONFIG_CPU_SH4A)
	unsigned long val;

	val = (UBC_CBR_ID_INST \| UBC_CBR_RW_READ \| UBC_CBR_CE);
	val \|= (UBC_CBR_AIE \| UBC_CBR_AIV_SET(asid));

	ctrl_outl(val, UBC_CBR0);
	ctrl_outl(pc, UBC_CAR0);
	ctrl_outl(0x0, UBC_CAMR0);
	ctrl_outl(0x0, UBC_CBCR);

	val = (UBC_CRR_RES \| UBC_CRR_PCB \| UBC_CRR_BIE);
	ctrl_outl(val, UBC_CRR0);

	/* Read UBC register that we wrote last, for checking update */
	val = ctrl_inl(UBC_CRR0);

	#else /* CONFIG_CPU_SH4A */
	ctrl_outl(pc, UBC_BARA);

	#ifdef CONFIG_MMU
	ctrl_outb(asid, UBC_BASRA);
	#endif

	ctrl_outl(0, UBC_BAMRA);

	if (current_cpu_data.type == CPU_SH7729 \|\|
	current_cpu_data.type == CPU_SH7710 \|\|
	current_cpu_data.type == CPU_SH7712) {
	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);
	}
	#endif /* CONFIG_CPU_SH4A */
	}

	/*
	* 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_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 \|= cpu_asid(smp_processor_id(), next->mm);
	#endif
	ubc_set_tracing(asid, next->thread.ubc_pc);
	} else {
	#if defined(CONFIG_CPU_SH4A)
	ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
	ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
	#else
	ctrl_outw(0, UBC_BBRA);
	ctrl_outw(0, UBC_BBRB);
	#endif
	}

	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
	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
	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)
	{
	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
	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)
	{
	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
	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 __user ufilename, char __user __user *uargv,
	char __user * __user *uenvp, unsigned long r7,
	struct pt_regs __regs)
	{
	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
	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) {
	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 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);

	#ifdef CONFIG_FRAME_POINTER
	if (in_sched_functions(pc)) {
	unsigned long schedule_frame = (unsigned long)p->thread.sp;
	return ((unsigned long *)schedule_frame)[21];
	}
	#endif

	return pc;
	}

	asmlinkage void break_point_trap(void)
	{
	/* Clear tracing. */
	#if defined(CONFIG_CPU_SH4A)
	ctrl_outl(UBC_CBR_INIT, UBC_CBR0);
	ctrl_outl(UBC_CRR_INIT, UBC_CRR0);
	#else
	ctrl_outw(0, UBC_BBRA);
	ctrl_outw(0, UBC_BBRB);
	#endif
	current->thread.ubc_pc = 0;
	ubc_usercnt -= 1;

	force_sig(SIGTRAP, current);
	}