[linux-2.6-block.git] / arch / mips / kernel / process.c

/*
 * 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) 1994 - 1999, 2000 by Ralf Baechle and others.
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 * Copyright (C) 2004 Thiemo Seufer
 */
#include <linux/config.h>
#include <linux/errno.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/mman.h>
#include <linux/personality.h>
#include <linux/sys.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/init.h>
#include <linux/completion.h>

#include <asm/abi.h>
#include <asm/bootinfo.h>
#include <asm/cpu.h>
#include <asm/dsp.h>
#include <asm/fpu.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/mipsregs.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/elf.h>
#include <asm/isadep.h>
#include <asm/inst.h>

/*
 * The idle thread. There's no useful work to be done, so just try to conserve
 * power and have a low exit latency (ie sit in a loop waiting for somebody to
 * say that they'd like to reschedule)
 */
ATTRIB_NORET void cpu_idle(void)
{
	/* endless idle loop with no priority at all */
	while (1) {
		while (!need_resched())
			if (cpu_wait)
				(*cpu_wait)();
		preempt_enable_no_resched();
		schedule();
		preempt_disable();
	}
}

extern int do_signal(sigset_t *oldset, struct pt_regs *regs);
extern int do_signal32(sigset_t *oldset, struct pt_regs *regs);

/*
 * Native o32 and N64 ABI without DSP ASE
 */
extern int setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
        int signr, sigset_t *set);
extern int setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
        int signr, sigset_t *set, siginfo_t *info);

struct mips_abi mips_abi = {
	.do_signal	= do_signal,
#ifdef CONFIG_TRAD_SIGNALS
	.setup_frame	= setup_frame,
#endif
	.setup_rt_frame	= setup_rt_frame
};

#ifdef CONFIG_MIPS32_O32
/*
 * o32 compatibility on 64-bit kernels, without DSP ASE
 */
extern int setup_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
        int signr, sigset_t *set);
extern int setup_rt_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
        int signr, sigset_t *set, siginfo_t *info);

struct mips_abi mips_abi_32 = {
	.do_signal	= do_signal32,
	.setup_frame	= setup_frame_32,
	.setup_rt_frame	= setup_rt_frame_32
};
#endif /* CONFIG_MIPS32_O32 */

#ifdef CONFIG_MIPS32_N32
/*
 * N32 on 64-bit kernels, without DSP ASE
 */
extern int setup_rt_frame_n32(struct k_sigaction * ka, struct pt_regs *regs,
        int signr, sigset_t *set, siginfo_t *info);

struct mips_abi mips_abi_n32 = {
	.do_signal	= do_signal,
	.setup_rt_frame	= setup_rt_frame_n32
};
#endif /* CONFIG_MIPS32_N32 */

asmlinkage void ret_from_fork(void);

void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
{
	unsigned long status;

	/* New thread loses kernel privileges. */
	status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|KU_MASK);
#ifdef CONFIG_64BIT
	status &= ~ST0_FR;
	status |= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR;
#endif
	status |= KU_USER;
	regs->cp0_status = status;
	clear_used_math();
	lose_fpu();
	if (cpu_has_dsp)
		__init_dsp();
	regs->cp0_epc = pc;
	regs->regs[29] = sp;
	current_thread_info()->addr_limit = USER_DS;
}

void exit_thread(void)
{
}

void flush_thread(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 = p->thread_info;
	struct pt_regs *childregs;
	long childksp;
	p->set_child_tid = p->clear_child_tid = NULL;

	childksp = (unsigned long)ti + THREAD_SIZE - 32;

	preempt_disable();

	if (is_fpu_owner())
		save_fp(p);

	if (cpu_has_dsp)
		save_dsp(p);

	preempt_enable();

	/* set up new TSS. */
	childregs = (struct pt_regs *) childksp - 1;
	*childregs = *regs;
	childregs->regs[7] = 0;	/* Clear error flag */

#if defined(CONFIG_BINFMT_IRIX)
	if (current->personality != PER_LINUX) {
		/* Under IRIX things are a little different. */
		childregs->regs[3] = 1;
		regs->regs[3] = 0;
	}
#endif
	childregs->regs[2] = 0;	/* Child gets zero as return value */
	regs->regs[2] = p->pid;

	if (childregs->cp0_status & ST0_CU0) {
		childregs->regs[28] = (unsigned long) ti;
		childregs->regs[29] = childksp;
		ti->addr_limit = KERNEL_DS;
	} else {
		childregs->regs[29] = usp;
		ti->addr_limit = USER_DS;
	}
	p->thread.reg29 = (unsigned long) childregs;
	p->thread.reg31 = (unsigned long) ret_from_fork;

	/*
	 * New tasks lose permission to use the fpu. This accelerates context
	 * switching for most programs since they don't use the fpu.
	 */
	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
	childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
	clear_tsk_thread_flag(p, TIF_USEDFPU);

	if (clone_flags & CLONE_SETTLS)
		ti->tp_value = regs->regs[7];

	return 0;
}

/* Fill in the fpu structure for a core dump.. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
{
	memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));

	return 1;
}

void dump_regs(elf_greg_t *gp, struct pt_regs *regs)
{
	int i;

	for (i = 0; i < EF_R0; i++)
		gp[i] = 0;
	gp[EF_R0] = 0;
	for (i = 1; i <= 31; i++)
		gp[EF_R0 + i] = regs->regs[i];
	gp[EF_R26] = 0;
	gp[EF_R27] = 0;
	gp[EF_LO] = regs->lo;
	gp[EF_HI] = regs->hi;
	gp[EF_CP0_EPC] = regs->cp0_epc;
	gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
	gp[EF_CP0_STATUS] = regs->cp0_status;
	gp[EF_CP0_CAUSE] = regs->cp0_cause;
#ifdef EF_UNUSED0
	gp[EF_UNUSED0] = 0;
#endif
}

int dump_task_regs (struct task_struct *tsk, elf_gregset_t *regs)
{
	struct thread_info *ti = tsk->thread_info;
	long ksp = (unsigned long)ti + THREAD_SIZE - 32;
	dump_regs(&(*regs)[0], (struct pt_regs *) ksp - 1);
	return 1;
}

int dump_task_fpu (struct task_struct *t, elf_fpregset_t *fpr)
{
	memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));

	return 1;
}

/*
 * Create a kernel thread
 */
ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *))
{
	do_exit(fn(arg));
}

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

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

	regs.regs[4] = (unsigned long) arg;
	regs.regs[5] = (unsigned long) fn;
	regs.cp0_epc = (unsigned long) kernel_thread_helper;
	regs.cp0_status = read_c0_status();
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
	regs.cp0_status &= ~(ST0_KUP | ST0_IEC);
	regs.cp0_status |= ST0_IEP;
#else
	regs.cp0_status |= ST0_EXL;
#endif

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

static struct mips_frame_info {
	void *func;
	int omit_fp;	/* compiled without fno-omit-frame-pointer */
	int frame_offset;
	int pc_offset;
} schedule_frame, mfinfo[] = {
	{ schedule, 0 },	/* must be first */
	/* arch/mips/kernel/semaphore.c */
	{ __down, 1 },
	{ __down_interruptible, 1 },
	/* kernel/sched.c */
#ifdef CONFIG_PREEMPT
	{ preempt_schedule, 0 },
#endif
	{ wait_for_completion, 0 },
	{ interruptible_sleep_on, 0 },
	{ interruptible_sleep_on_timeout, 0 },
	{ sleep_on, 0 },
	{ sleep_on_timeout, 0 },
	{ yield, 0 },
	{ io_schedule, 0 },
	{ io_schedule_timeout, 0 },
#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
	{ __preempt_spin_lock, 0 },
	{ __preempt_write_lock, 0 },
#endif
	/* kernel/timer.c */
	{ schedule_timeout, 1 },
/*	{ nanosleep_restart, 1 }, */
	/* lib/rwsem-spinlock.c */
	{ __down_read, 1 },
	{ __down_write, 1 },
};

static int mips_frame_info_initialized;
static int __init get_frame_info(struct mips_frame_info *info)
{
	int i;
	void *func = info->func;
	union mips_instruction *ip = (union mips_instruction *)func;
	info->pc_offset = -1;
	info->frame_offset = info->omit_fp ? 0 : -1;
	for (i = 0; i < 128; i++, ip++) {
		/* if jal, jalr, jr, stop. */
		if (ip->j_format.opcode == jal_op ||
		    (ip->r_format.opcode == spec_op &&
		     (ip->r_format.func == jalr_op ||
		      ip->r_format.func == jr_op)))
			break;

		if (
#ifdef CONFIG_32BIT
		    ip->i_format.opcode == sw_op &&
#endif
#ifdef CONFIG_64BIT
		    ip->i_format.opcode == sd_op &&
#endif
		    ip->i_format.rs == 29)
		{
			/* sw / sd $ra, offset($sp) */
			if (ip->i_format.rt == 31) {
				if (info->pc_offset != -1)
					continue;
				info->pc_offset =
					ip->i_format.simmediate / sizeof(long);
			}
			/* sw / sd $s8, offset($sp) */
			if (ip->i_format.rt == 30) {
//#if 0	/* gcc 3.4 does aggressive optimization... */
				if (info->frame_offset != -1)
					continue;
//#endif
				info->frame_offset =
					ip->i_format.simmediate / sizeof(long);
			}
		}
	}
	if (info->pc_offset == -1 || info->frame_offset == -1) {
		printk("Can't analyze prologue code at %p\n", func);
		info->pc_offset = -1;
		info->frame_offset = -1;
		return -1;
	}

	return 0;
}

static int __init frame_info_init(void)
{
	int i, found;
	for (i = 0; i < ARRAY_SIZE(mfinfo); i++)
		if (get_frame_info(&mfinfo[i]))
			return -1;
	schedule_frame = mfinfo[0];
	/* bubble sort */
	do {
		struct mips_frame_info tmp;
		found = 0;
		for (i = 1; i < ARRAY_SIZE(mfinfo); i++) {
			if (mfinfo[i-1].func > mfinfo[i].func) {
				tmp = mfinfo[i];
				mfinfo[i] = mfinfo[i-1];
				mfinfo[i-1] = tmp;
				found = 1;
			}
		}
	} while (found);
	mips_frame_info_initialized = 1;
	return 0;
}

arch_initcall(frame_info_init);

/*
 * Return saved PC of a blocked thread.
 */
unsigned long thread_saved_pc(struct task_struct *tsk)
{
	struct thread_struct *t = &tsk->thread;

	/* New born processes are a special case */
	if (t->reg31 == (unsigned long) ret_from_fork)
		return t->reg31;

	if (schedule_frame.pc_offset < 0)
		return 0;
	return ((unsigned long *)t->reg29)[schedule_frame.pc_offset];
}

/* get_wchan - a maintenance nightmare^W^Wpain in the ass ...  */
unsigned long get_wchan(struct task_struct *p)
{
	unsigned long stack_page;
	unsigned long frame, pc;

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

	stack_page = (unsigned long)p->thread_info;
	if (!stack_page || !mips_frame_info_initialized)
		return 0;

	pc = thread_saved_pc(p);
	if (!in_sched_functions(pc))
		return pc;

	frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
	do {
		int i;

		if (frame < stack_page || frame > stack_page + THREAD_SIZE - 32)
			return 0;

		for (i = ARRAY_SIZE(mfinfo) - 1; i >= 0; i--) {
			if (pc >= (unsigned long) mfinfo[i].func)
				break;
		}
		if (i < 0)
			break;

		if (mfinfo[i].omit_fp)
			break;
		pc = ((unsigned long *)frame)[mfinfo[i].pc_offset];
		frame = ((unsigned long *)frame)[mfinfo[i].frame_offset];
	} while (in_sched_functions(pc));

	return pc;
}

EXPORT_SYMBOL(get_wchan);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* This file is subject to the terms and conditions of the GNU General Public
	3	* License. See the file "COPYING" in the main directory of this archive
	4	* for more details.
	5	*
	6	* Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
	7	* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
	8	* Copyright (C) 2004 Thiemo Seufer
	9	*/
	10	#include <linux/config.h>
	11	#include <linux/errno.h>
	12	#include <linux/module.h>
	13	#include <linux/sched.h>
	14	#include <linux/kernel.h>
	15	#include <linux/mm.h>
	16	#include <linux/stddef.h>
	17	#include <linux/unistd.h>
	18	#include <linux/ptrace.h>
	19	#include <linux/slab.h>
	20	#include <linux/mman.h>
	21	#include <linux/personality.h>
	22	#include <linux/sys.h>
	23	#include <linux/user.h>
	24	#include <linux/a.out.h>
	25	#include <linux/init.h>
	26	#include <linux/completion.h>
	27
e50c0a8f	28	#include <asm/abi.h>
1da177e4 LT	29	#include <asm/bootinfo.h>
1da177e4 LT	30	#include <asm/cpu.h>
e50c0a8f	31	#include <asm/dsp.h>
1da177e4 LT	32	#include <asm/fpu.h>
	33	#include <asm/pgtable.h>
	34	#include <asm/system.h>
	35	#include <asm/mipsregs.h>
	36	#include <asm/processor.h>
	37	#include <asm/uaccess.h>
	38	#include <asm/io.h>
	39	#include <asm/elf.h>
	40	#include <asm/isadep.h>
	41	#include <asm/inst.h>
	42
1da177e4 LT	43	/*
	44	* The idle thread. There's no useful work to be done, so just try to conserve
	45	* power and have a low exit latency (ie sit in a loop waiting for somebody to
	46	* say that they'd like to reschedule)
	47	*/
	48	ATTRIB_NORET void cpu_idle(void)
	49	{
	50	/* endless idle loop with no priority at all */
	51	while (1) {
	52	while (!need_resched())
	53	if (cpu_wait)
	54	(*cpu_wait)();
5bfb5d69	55	preempt_enable_no_resched();
1da177e4	56	schedule();
5bfb5d69	57	preempt_disable();
1da177e4 LT	58	}
	59	}
	60
e50c0a8f RB	61	extern int do_signal(sigset_t oldset, struct pt_regs regs);
	62	extern int do_signal32(sigset_t oldset, struct pt_regs regs);
	63
	64	/*
	65	* Native o32 and N64 ABI without DSP ASE
	66	*/
129bc8f7	67	extern int setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
e50c0a8f	68	int signr, sigset_t *set);
129bc8f7	69	extern int setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
e50c0a8f RB	70	int signr, sigset_t set, siginfo_t info);
	71
	72	struct mips_abi mips_abi = {
	73	.do_signal = do_signal,
	74	#ifdef CONFIG_TRAD_SIGNALS
	75	.setup_frame = setup_frame,
	76	#endif
	77	.setup_rt_frame = setup_rt_frame
	78	};
	79
	80	#ifdef CONFIG_MIPS32_O32
	81	/*
	82	* o32 compatibility on 64-bit kernels, without DSP ASE
	83	*/
129bc8f7	84	extern int setup_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
e50c0a8f	85	int signr, sigset_t *set);
129bc8f7	86	extern int setup_rt_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
e50c0a8f RB	87	int signr, sigset_t set, siginfo_t info);
	88
	89	struct mips_abi mips_abi_32 = {
	90	.do_signal = do_signal32,
	91	.setup_frame = setup_frame_32,
	92	.setup_rt_frame = setup_rt_frame_32
	93	};
	94	#endif /* CONFIG_MIPS32_O32 */
	95
	96	#ifdef CONFIG_MIPS32_N32
	97	/*
	98	* N32 on 64-bit kernels, without DSP ASE
	99	*/
129bc8f7	100	extern int setup_rt_frame_n32(struct k_sigaction * ka, struct pt_regs *regs,
e50c0a8f RB	101	int signr, sigset_t set, siginfo_t info);
	102
	103	struct mips_abi mips_abi_n32 = {
	104	.do_signal = do_signal,
	105	.setup_rt_frame = setup_rt_frame_n32
	106	};
	107	#endif /* CONFIG_MIPS32_N32 */
	108
1da177e4 LT	109	asmlinkage void ret_from_fork(void);
	110
	111	void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
	112	{
	113	unsigned long status;
	114
	115	/* New thread loses kernel privileges. */
	116	status = regs->cp0_status & ~(ST0_CU0\|ST0_CU1\|KU_MASK);
875d43e7	117	#ifdef CONFIG_64BIT
1da177e4 LT	118	status &= ~ST0_FR;
	119	status \|= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR;
	120	#endif
	121	status \|= KU_USER;
	122	regs->cp0_status = status;
	123	clear_used_math();
	124	lose_fpu();
e50c0a8f RB	125	if (cpu_has_dsp)
e50c0a8f RB	126	__init_dsp();
1da177e4 LT	127	regs->cp0_epc = pc;
	128	regs->regs[29] = sp;
	129	current_thread_info()->addr_limit = USER_DS;
	130	}
	131
	132	void exit_thread(void)
	133	{
	134	}
	135
	136	void flush_thread(void)
	137	{
	138	}
	139
	140	int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
	141	unsigned long unused, struct task_struct p, struct pt_regs regs)
	142	{
	143	struct thread_info *ti = p->thread_info;
	144	struct pt_regs *childregs;
	145	long childksp;
3c37026d	146	p->set_child_tid = p->clear_child_tid = NULL;
1da177e4 LT	147
	148	childksp = (unsigned long)ti + THREAD_SIZE - 32;
	149
	150	preempt_disable();
	151
e50c0a8f	152	if (is_fpu_owner())
1da177e4	153	save_fp(p);
e50c0a8f RB	154
	155	if (cpu_has_dsp)
	156	save_dsp(p);
1da177e4 LT	157
	158	preempt_enable();
	159
	160	/* set up new TSS. */
	161	childregs = (struct pt_regs *) childksp - 1;
	162	childregs = regs;
	163	childregs->regs[7] = 0; /* Clear error flag */
	164
	165	#if defined(CONFIG_BINFMT_IRIX)
	166	if (current->personality != PER_LINUX) {
	167	/* Under IRIX things are a little different. */
	168	childregs->regs[3] = 1;
	169	regs->regs[3] = 0;
	170	}
	171	#endif
	172	childregs->regs[2] = 0; /* Child gets zero as return value */
	173	regs->regs[2] = p->pid;
	174
	175	if (childregs->cp0_status & ST0_CU0) {
	176	childregs->regs[28] = (unsigned long) ti;
	177	childregs->regs[29] = childksp;
	178	ti->addr_limit = KERNEL_DS;
	179	} else {
	180	childregs->regs[29] = usp;
	181	ti->addr_limit = USER_DS;
	182	}
	183	p->thread.reg29 = (unsigned long) childregs;
	184	p->thread.reg31 = (unsigned long) ret_from_fork;
	185
	186	/*
	187	* New tasks lose permission to use the fpu. This accelerates context
	188	* switching for most programs since they don't use the fpu.
	189	*/
	190	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2\|ST0_CU1);
	191	childregs->cp0_status &= ~(ST0_CU2\|ST0_CU1);
	192	clear_tsk_thread_flag(p, TIF_USEDFPU);
	193
3c37026d RB	194	if (clone_flags & CLONE_SETTLS)
	195	ti->tp_value = regs->regs[7];
	196
1da177e4 LT	197	return 0;
	198	}
	199
	200	/* Fill in the fpu structure for a core dump.. */
	201	int dump_fpu(struct pt_regs regs, elf_fpregset_t r)
	202	{
	203	memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));
	204
	205	return 1;
	206	}
	207
	208	void dump_regs(elf_greg_t gp, struct pt_regs regs)
	209	{
	210	int i;
	211
	212	for (i = 0; i < EF_R0; i++)
	213	gp[i] = 0;
	214	gp[EF_R0] = 0;
	215	for (i = 1; i <= 31; i++)
	216	gp[EF_R0 + i] = regs->regs[i];
	217	gp[EF_R26] = 0;
	218	gp[EF_R27] = 0;
	219	gp[EF_LO] = regs->lo;
	220	gp[EF_HI] = regs->hi;
	221	gp[EF_CP0_EPC] = regs->cp0_epc;
	222	gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
	223	gp[EF_CP0_STATUS] = regs->cp0_status;
	224	gp[EF_CP0_CAUSE] = regs->cp0_cause;
	225	#ifdef EF_UNUSED0
	226	gp[EF_UNUSED0] = 0;
	227	#endif
	228	}
	229
71e0e556 RB	230	int dump_task_regs (struct task_struct tsk, elf_gregset_t regs)
	231	{
	232	struct thread_info *ti = tsk->thread_info;
	233	long ksp = (unsigned long)ti + THREAD_SIZE - 32;
	234	dump_regs(&(regs)[0], (struct pt_regs ) ksp - 1);
	235	return 1;
	236	}
	237
1da177e4 LT	238	int dump_task_fpu (struct task_struct t, elf_fpregset_t fpr)
	239	{
	240	memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
	241
	242	return 1;
	243	}
	244
	245	/*
	246	* Create a kernel thread
	247	*/
	248	ATTRIB_NORET void kernel_thread_helper(void arg, int (fn)(void *))
	249	{
	250	do_exit(fn(arg));
	251	}
	252
	253	long kernel_thread(int (fn)(void ), void *arg, unsigned long flags)
	254	{
	255	struct pt_regs regs;
	256
	257	memset(&regs, 0, sizeof(regs));
	258
	259	regs.regs[4] = (unsigned long) arg;
	260	regs.regs[5] = (unsigned long) fn;
	261	regs.cp0_epc = (unsigned long) kernel_thread_helper;
	262	regs.cp0_status = read_c0_status();
	263	#if defined(CONFIG_CPU_R3000) \|\| defined(CONFIG_CPU_TX39XX)
	264	regs.cp0_status &= ~(ST0_KUP \| ST0_IEC);
	265	regs.cp0_status \|= ST0_IEP;
	266	#else
	267	regs.cp0_status \|= ST0_EXL;
	268	#endif
	269
	270	/* Ok, create the new process.. */
	271	return do_fork(flags \| CLONE_VM \| CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
	272	}
	273
dc953df1 TS	274	static struct mips_frame_info {
	275	void *func;
	276	int omit_fp; /* compiled without fno-omit-frame-pointer */
1da177e4 LT	277	int frame_offset;
1da177e4 LT	278	int pc_offset;
dc953df1 TS	279	} schedule_frame, mfinfo[] = {
	280	{ schedule, 0 }, /* must be first */
	281	/* arch/mips/kernel/semaphore.c */
	282	{ __down, 1 },
	283	{ __down_interruptible, 1 },
	284	/* kernel/sched.c */
	285	#ifdef CONFIG_PREEMPT
	286	{ preempt_schedule, 0 },
	287	#endif
	288	{ wait_for_completion, 0 },
	289	{ interruptible_sleep_on, 0 },
	290	{ interruptible_sleep_on_timeout, 0 },
	291	{ sleep_on, 0 },
	292	{ sleep_on_timeout, 0 },
	293	{ yield, 0 },
	294	{ io_schedule, 0 },
	295	{ io_schedule_timeout, 0 },
	296	#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
	297	{ __preempt_spin_lock, 0 },
	298	{ __preempt_write_lock, 0 },
	299	#endif
	300	/* kernel/timer.c */
	301	{ schedule_timeout, 1 },
	302	/* { nanosleep_restart, 1 }, */
	303	/* lib/rwsem-spinlock.c */
	304	{ __down_read, 1 },
	305	{ __down_write, 1 },
1da177e4	306	};
dc953df1	307
1da177e4	308	static int mips_frame_info_initialized;
dc953df1	309	static int __init get_frame_info(struct mips_frame_info *info)
1da177e4 LT	310	{
1da177e4 LT	311	int i;
dc953df1	312	void *func = info->func;
1da177e4 LT	313	union mips_instruction ip = (union mips_instruction )func;
1da177e4 LT	314	info->pc_offset = -1;
dc953df1	315	info->frame_offset = info->omit_fp ? 0 : -1;
1da177e4 LT	316	for (i = 0; i < 128; i++, ip++) {
	317	/* if jal, jalr, jr, stop. */
	318	if (ip->j_format.opcode == jal_op \|\|
	319	(ip->r_format.opcode == spec_op &&
	320	(ip->r_format.func == jalr_op \|\|
	321	ip->r_format.func == jr_op)))
	322	break;
	323
	324	if (
875d43e7	325	#ifdef CONFIG_32BIT
1da177e4 LT	326	ip->i_format.opcode == sw_op &&
1da177e4 LT	327	#endif
875d43e7	328	#ifdef CONFIG_64BIT
1da177e4 LT	329	ip->i_format.opcode == sd_op &&
	330	#endif
	331	ip->i_format.rs == 29)
	332	{
	333	/* sw / sd $ra, offset($sp) */
	334	if (ip->i_format.rt == 31) {
	335	if (info->pc_offset != -1)
dc953df1	336	continue;
1da177e4 LT	337	info->pc_offset =
	338	ip->i_format.simmediate / sizeof(long);
	339	}
	340	/* sw / sd $s8, offset($sp) */
	341	if (ip->i_format.rt == 30) {
dc953df1	342	//#if 0 /* gcc 3.4 does aggressive optimization... */
1da177e4	343	if (info->frame_offset != -1)
dc953df1 TS	344	continue;
dc953df1 TS	345	//#endif
1da177e4 LT	346	info->frame_offset =
	347	ip->i_format.simmediate / sizeof(long);
	348	}
	349	}
	350	}
	351	if (info->pc_offset == -1 \|\| info->frame_offset == -1) {
	352	printk("Can't analyze prologue code at %p\n", func);
	353	info->pc_offset = -1;
	354	info->frame_offset = -1;
	355	return -1;
	356	}
	357
	358	return 0;
	359	}
	360
	361	static int __init frame_info_init(void)
	362	{
dc953df1 TS	363	int i, found;
	364	for (i = 0; i < ARRAY_SIZE(mfinfo); i++)
	365	if (get_frame_info(&mfinfo[i]))
	366	return -1;
	367	schedule_frame = mfinfo[0];
	368	/* bubble sort */
	369	do {
	370	struct mips_frame_info tmp;
	371	found = 0;
	372	for (i = 1; i < ARRAY_SIZE(mfinfo); i++) {
	373	if (mfinfo[i-1].func > mfinfo[i].func) {
	374	tmp = mfinfo[i];
	375	mfinfo[i] = mfinfo[i-1];
	376	mfinfo[i-1] = tmp;
	377	found = 1;
	378	}
	379	}
	380	} while (found);
	381	mips_frame_info_initialized = 1;
1da177e4 LT	382	return 0;
	383	}
	384
	385	arch_initcall(frame_info_init);
	386
	387	/*
	388	* Return saved PC of a blocked thread.
	389	*/
	390	unsigned long thread_saved_pc(struct task_struct *tsk)
	391	{
	392	struct thread_struct *t = &tsk->thread;
	393
	394	/* New born processes are a special case */
	395	if (t->reg31 == (unsigned long) ret_from_fork)
	396	return t->reg31;
	397
	398	if (schedule_frame.pc_offset < 0)
	399	return 0;
	400	return ((unsigned long *)t->reg29)[schedule_frame.pc_offset];
	401	}
	402
	403	/* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */
	404	unsigned long get_wchan(struct task_struct *p)
	405	{
dc953df1	406	unsigned long stack_page;
1da177e4 LT	407	unsigned long frame, pc;
	408
	409	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	410	return 0;
	411
dc953df1 TS	412	stack_page = (unsigned long)p->thread_info;
dc953df1 TS	413	if (!stack_page \|\| !mips_frame_info_initialized)
1da177e4	414	return 0;
dc953df1	415
1da177e4 LT	416	pc = thread_saved_pc(p);
1da177e4 LT	417	if (!in_sched_functions(pc))
dc953df1	418	return pc;
1da177e4	419
1da177e4	420	frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
dc953df1 TS	421	do {
dc953df1 TS	422	int i;
1da177e4	423
dc953df1 TS	424	if (frame < stack_page \|\| frame > stack_page + THREAD_SIZE - 32)
dc953df1 TS	425	return 0;
1da177e4	426
dc953df1 TS	427	for (i = ARRAY_SIZE(mfinfo) - 1; i >= 0; i--) {
	428	if (pc >= (unsigned long) mfinfo[i].func)
	429	break;
	430	}
	431	if (i < 0)
	432	break;
1da177e4	433
dc953df1 TS	434	if (mfinfo[i].omit_fp)
	435	break;
	436	pc = ((unsigned long *)frame)[mfinfo[i].pc_offset];
	437	frame = ((unsigned long *)frame)[mfinfo[i].frame_offset];
	438	} while (in_sched_functions(pc));
1da177e4 LT	439
	440	return pc;
	441	}
	442
	443	EXPORT_SYMBOL(get_wchan);