[mirror_ubuntu-zesty-kernel.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) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org)
 * 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 void do_signal(struct pt_regs *regs);
extern void do_signal32(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 = task_thread_info(p);
	struct pt_regs *childregs;
	long childksp;
	p->set_child_tid = p->clear_child_tid = NULL;

	childksp = (unsigned long)task_stack_page(p) + 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 elf_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)
{
	elf_dump_regs(*regs, task_pt_regs(tsk));
	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)task_stack_page(p);
	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.
40ac5d47	7	* Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org)
1da177e4 LT	8	* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
	9	* Copyright (C) 2004 Thiemo Seufer
	10	*/
	11	#include <linux/config.h>
	12	#include <linux/errno.h>
	13	#include <linux/module.h>
	14	#include <linux/sched.h>
	15	#include <linux/kernel.h>
	16	#include <linux/mm.h>
	17	#include <linux/stddef.h>
	18	#include <linux/unistd.h>
	19	#include <linux/ptrace.h>
	20	#include <linux/slab.h>
	21	#include <linux/mman.h>
	22	#include <linux/personality.h>
	23	#include <linux/sys.h>
	24	#include <linux/user.h>
	25	#include <linux/a.out.h>
	26	#include <linux/init.h>
	27	#include <linux/completion.h>
	28
e50c0a8f	29	#include <asm/abi.h>
1da177e4 LT	30	#include <asm/bootinfo.h>
1da177e4 LT	31	#include <asm/cpu.h>
e50c0a8f	32	#include <asm/dsp.h>
1da177e4 LT	33	#include <asm/fpu.h>
	34	#include <asm/pgtable.h>
	35	#include <asm/system.h>
	36	#include <asm/mipsregs.h>
	37	#include <asm/processor.h>
	38	#include <asm/uaccess.h>
	39	#include <asm/io.h>
	40	#include <asm/elf.h>
	41	#include <asm/isadep.h>
	42	#include <asm/inst.h>
	43
1da177e4 LT	44	/*
	45	* The idle thread. There's no useful work to be done, so just try to conserve
	46	* power and have a low exit latency (ie sit in a loop waiting for somebody to
	47	* say that they'd like to reschedule)
	48	*/
	49	ATTRIB_NORET void cpu_idle(void)
	50	{
	51	/* endless idle loop with no priority at all */
	52	while (1) {
	53	while (!need_resched())
	54	if (cpu_wait)
	55	(*cpu_wait)();
5bfb5d69	56	preempt_enable_no_resched();
1da177e4	57	schedule();
5bfb5d69	58	preempt_disable();
1da177e4 LT	59	}
	60	}
	61
40ac5d47 RB	62	extern void do_signal(struct pt_regs *regs);
40ac5d47 RB	63	extern void do_signal32(struct pt_regs *regs);
e50c0a8f RB	64
	65	/*
	66	* Native o32 and N64 ABI without DSP ASE
	67	*/
129bc8f7	68	extern int setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
e50c0a8f	69	int signr, sigset_t *set);
129bc8f7	70	extern int setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
e50c0a8f RB	71	int signr, sigset_t set, siginfo_t info);
	72
	73	struct mips_abi mips_abi = {
	74	.do_signal = do_signal,
	75	#ifdef CONFIG_TRAD_SIGNALS
	76	.setup_frame = setup_frame,
	77	#endif
	78	.setup_rt_frame = setup_rt_frame
	79	};
	80
	81	#ifdef CONFIG_MIPS32_O32
	82	/*
	83	* o32 compatibility on 64-bit kernels, without DSP ASE
	84	*/
129bc8f7	85	extern int setup_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
e50c0a8f	86	int signr, sigset_t *set);
129bc8f7	87	extern int setup_rt_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
e50c0a8f RB	88	int signr, sigset_t set, siginfo_t info);
	89
	90	struct mips_abi mips_abi_32 = {
	91	.do_signal = do_signal32,
	92	.setup_frame = setup_frame_32,
	93	.setup_rt_frame = setup_rt_frame_32
	94	};
	95	#endif /* CONFIG_MIPS32_O32 */
	96
	97	#ifdef CONFIG_MIPS32_N32
	98	/*
	99	* N32 on 64-bit kernels, without DSP ASE
	100	*/
129bc8f7	101	extern int setup_rt_frame_n32(struct k_sigaction * ka, struct pt_regs *regs,
e50c0a8f RB	102	int signr, sigset_t set, siginfo_t info);
	103
	104	struct mips_abi mips_abi_n32 = {
	105	.do_signal = do_signal,
	106	.setup_rt_frame = setup_rt_frame_n32
	107	};
	108	#endif /* CONFIG_MIPS32_N32 */
	109
1da177e4 LT	110	asmlinkage void ret_from_fork(void);
	111
	112	void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
	113	{
	114	unsigned long status;
	115
	116	/* New thread loses kernel privileges. */
	117	status = regs->cp0_status & ~(ST0_CU0\|ST0_CU1\|KU_MASK);
875d43e7	118	#ifdef CONFIG_64BIT
1da177e4 LT	119	status &= ~ST0_FR;
	120	status \|= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR;
	121	#endif
	122	status \|= KU_USER;
	123	regs->cp0_status = status;
	124	clear_used_math();
	125	lose_fpu();
e50c0a8f RB	126	if (cpu_has_dsp)
e50c0a8f RB	127	__init_dsp();
1da177e4 LT	128	regs->cp0_epc = pc;
	129	regs->regs[29] = sp;
	130	current_thread_info()->addr_limit = USER_DS;
	131	}
	132
	133	void exit_thread(void)
	134	{
	135	}
	136
	137	void flush_thread(void)
	138	{
	139	}
	140
	141	int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
	142	unsigned long unused, struct task_struct p, struct pt_regs regs)
	143	{
75bb07e7	144	struct thread_info *ti = task_thread_info(p);
1da177e4 LT	145	struct pt_regs *childregs;
1da177e4 LT	146	long childksp;
3c37026d	147	p->set_child_tid = p->clear_child_tid = NULL;
1da177e4	148
75bb07e7	149	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
1da177e4 LT	150
	151	preempt_disable();
	152
e50c0a8f	153	if (is_fpu_owner())
1da177e4	154	save_fp(p);
e50c0a8f RB	155
	156	if (cpu_has_dsp)
	157	save_dsp(p);
1da177e4 LT	158
	159	preempt_enable();
	160
	161	/* set up new TSS. */
	162	childregs = (struct pt_regs *) childksp - 1;
	163	childregs = regs;
	164	childregs->regs[7] = 0; /* Clear error flag */
	165
	166	#if defined(CONFIG_BINFMT_IRIX)
	167	if (current->personality != PER_LINUX) {
	168	/* Under IRIX things are a little different. */
	169	childregs->regs[3] = 1;
	170	regs->regs[3] = 0;
	171	}
	172	#endif
	173	childregs->regs[2] = 0; /* Child gets zero as return value */
	174	regs->regs[2] = p->pid;
	175
	176	if (childregs->cp0_status & ST0_CU0) {
	177	childregs->regs[28] = (unsigned long) ti;
	178	childregs->regs[29] = childksp;
	179	ti->addr_limit = KERNEL_DS;
	180	} else {
	181	childregs->regs[29] = usp;
	182	ti->addr_limit = USER_DS;
	183	}
	184	p->thread.reg29 = (unsigned long) childregs;
	185	p->thread.reg31 = (unsigned long) ret_from_fork;
	186
	187	/*
	188	* New tasks lose permission to use the fpu. This accelerates context
	189	* switching for most programs since they don't use the fpu.
	190	*/
	191	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2\|ST0_CU1);
	192	childregs->cp0_status &= ~(ST0_CU2\|ST0_CU1);
	193	clear_tsk_thread_flag(p, TIF_USEDFPU);
	194
3c37026d RB	195	if (clone_flags & CLONE_SETTLS)
	196	ti->tp_value = regs->regs[7];
	197
1da177e4 LT	198	return 0;
	199	}
	200
	201	/* Fill in the fpu structure for a core dump.. */
	202	int dump_fpu(struct pt_regs regs, elf_fpregset_t r)
	203	{
	204	memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));
	205
	206	return 1;
	207	}
	208
d56efda4	209	void elf_dump_regs(elf_greg_t gp, struct pt_regs regs)
1da177e4 LT	210	{
	211	int i;
	212
	213	for (i = 0; i < EF_R0; i++)
	214	gp[i] = 0;
	215	gp[EF_R0] = 0;
	216	for (i = 1; i <= 31; i++)
	217	gp[EF_R0 + i] = regs->regs[i];
	218	gp[EF_R26] = 0;
	219	gp[EF_R27] = 0;
	220	gp[EF_LO] = regs->lo;
	221	gp[EF_HI] = regs->hi;
	222	gp[EF_CP0_EPC] = regs->cp0_epc;
	223	gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
	224	gp[EF_CP0_STATUS] = regs->cp0_status;
	225	gp[EF_CP0_CAUSE] = regs->cp0_cause;
	226	#ifdef EF_UNUSED0
	227	gp[EF_UNUSED0] = 0;
	228	#endif
	229	}
	230
71e0e556 RB	231	int dump_task_regs (struct task_struct tsk, elf_gregset_t regs)
71e0e556 RB	232	{
40bc9c67	233	elf_dump_regs(*regs, task_pt_regs(tsk));
71e0e556 RB	234	return 1;
	235	}
	236
1da177e4 LT	237	int dump_task_fpu (struct task_struct t, elf_fpregset_t fpr)
	238	{
	239	memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
	240
	241	return 1;
	242	}
	243
	244	/*
	245	* Create a kernel thread
	246	*/
	247	ATTRIB_NORET void kernel_thread_helper(void arg, int (fn)(void *))
	248	{
	249	do_exit(fn(arg));
	250	}
	251
	252	long kernel_thread(int (fn)(void ), void *arg, unsigned long flags)
	253	{
	254	struct pt_regs regs;
	255
	256	memset(&regs, 0, sizeof(regs));
	257
	258	regs.regs[4] = (unsigned long) arg;
	259	regs.regs[5] = (unsigned long) fn;
	260	regs.cp0_epc = (unsigned long) kernel_thread_helper;
	261	regs.cp0_status = read_c0_status();
	262	#if defined(CONFIG_CPU_R3000) \|\| defined(CONFIG_CPU_TX39XX)
	263	regs.cp0_status &= ~(ST0_KUP \| ST0_IEC);
	264	regs.cp0_status \|= ST0_IEP;
	265	#else
	266	regs.cp0_status \|= ST0_EXL;
	267	#endif
	268
	269	/* Ok, create the new process.. */
	270	return do_fork(flags \| CLONE_VM \| CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
	271	}
	272
dc953df1 TS	273	static struct mips_frame_info {
	274	void *func;
	275	int omit_fp; /* compiled without fno-omit-frame-pointer */
1da177e4 LT	276	int frame_offset;
1da177e4 LT	277	int pc_offset;
dc953df1 TS	278	} schedule_frame, mfinfo[] = {
	279	{ schedule, 0 }, /* must be first */
	280	/* arch/mips/kernel/semaphore.c */
	281	{ __down, 1 },
	282	{ __down_interruptible, 1 },
	283	/* kernel/sched.c */
	284	#ifdef CONFIG_PREEMPT
	285	{ preempt_schedule, 0 },
	286	#endif
	287	{ wait_for_completion, 0 },
	288	{ interruptible_sleep_on, 0 },
	289	{ interruptible_sleep_on_timeout, 0 },
	290	{ sleep_on, 0 },
	291	{ sleep_on_timeout, 0 },
	292	{ yield, 0 },
	293	{ io_schedule, 0 },
	294	{ io_schedule_timeout, 0 },
	295	#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
	296	{ __preempt_spin_lock, 0 },
	297	{ __preempt_write_lock, 0 },
	298	#endif
	299	/* kernel/timer.c */
	300	{ schedule_timeout, 1 },
	301	/* { nanosleep_restart, 1 }, */
	302	/* lib/rwsem-spinlock.c */
	303	{ __down_read, 1 },
	304	{ __down_write, 1 },
1da177e4	305	};
dc953df1	306
1da177e4	307	static int mips_frame_info_initialized;
dc953df1	308	static int __init get_frame_info(struct mips_frame_info *info)
1da177e4 LT	309	{
1da177e4 LT	310	int i;
dc953df1	311	void *func = info->func;
1da177e4 LT	312	union mips_instruction ip = (union mips_instruction )func;
1da177e4 LT	313	info->pc_offset = -1;
dc953df1	314	info->frame_offset = info->omit_fp ? 0 : -1;
1da177e4 LT	315	for (i = 0; i < 128; i++, ip++) {
	316	/* if jal, jalr, jr, stop. */
	317	if (ip->j_format.opcode == jal_op \|\|
	318	(ip->r_format.opcode == spec_op &&
	319	(ip->r_format.func == jalr_op \|\|
	320	ip->r_format.func == jr_op)))
	321	break;
	322
	323	if (
875d43e7	324	#ifdef CONFIG_32BIT
1da177e4 LT	325	ip->i_format.opcode == sw_op &&
1da177e4 LT	326	#endif
875d43e7	327	#ifdef CONFIG_64BIT
1da177e4 LT	328	ip->i_format.opcode == sd_op &&
	329	#endif
	330	ip->i_format.rs == 29)
	331	{
	332	/* sw / sd $ra, offset($sp) */
	333	if (ip->i_format.rt == 31) {
	334	if (info->pc_offset != -1)
dc953df1	335	continue;
1da177e4 LT	336	info->pc_offset =
	337	ip->i_format.simmediate / sizeof(long);
	338	}
	339	/* sw / sd $s8, offset($sp) */
	340	if (ip->i_format.rt == 30) {
dc953df1	341	//#if 0 /* gcc 3.4 does aggressive optimization... */
1da177e4	342	if (info->frame_offset != -1)
dc953df1 TS	343	continue;
dc953df1 TS	344	//#endif
1da177e4 LT	345	info->frame_offset =
	346	ip->i_format.simmediate / sizeof(long);
	347	}
	348	}
	349	}
	350	if (info->pc_offset == -1 \|\| info->frame_offset == -1) {
	351	printk("Can't analyze prologue code at %p\n", func);
	352	info->pc_offset = -1;
	353	info->frame_offset = -1;
	354	return -1;
	355	}
	356
	357	return 0;
	358	}
	359
	360	static int __init frame_info_init(void)
	361	{
dc953df1 TS	362	int i, found;
	363	for (i = 0; i < ARRAY_SIZE(mfinfo); i++)
	364	if (get_frame_info(&mfinfo[i]))
	365	return -1;
	366	schedule_frame = mfinfo[0];
	367	/* bubble sort */
	368	do {
	369	struct mips_frame_info tmp;
	370	found = 0;
	371	for (i = 1; i < ARRAY_SIZE(mfinfo); i++) {
	372	if (mfinfo[i-1].func > mfinfo[i].func) {
	373	tmp = mfinfo[i];
	374	mfinfo[i] = mfinfo[i-1];
	375	mfinfo[i-1] = tmp;
	376	found = 1;
	377	}
	378	}
	379	} while (found);
	380	mips_frame_info_initialized = 1;
1da177e4 LT	381	return 0;
	382	}
	383
	384	arch_initcall(frame_info_init);
	385
	386	/*
	387	* Return saved PC of a blocked thread.
	388	*/
	389	unsigned long thread_saved_pc(struct task_struct *tsk)
	390	{
	391	struct thread_struct *t = &tsk->thread;
	392
	393	/* New born processes are a special case */
	394	if (t->reg31 == (unsigned long) ret_from_fork)
	395	return t->reg31;
	396
	397	if (schedule_frame.pc_offset < 0)
	398	return 0;
	399	return ((unsigned long *)t->reg29)[schedule_frame.pc_offset];
	400	}
	401
	402	/* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */
	403	unsigned long get_wchan(struct task_struct *p)
	404	{
dc953df1	405	unsigned long stack_page;
1da177e4 LT	406	unsigned long frame, pc;
	407
	408	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	409	return 0;
	410
75bb07e7	411	stack_page = (unsigned long)task_stack_page(p);
dc953df1	412	if (!stack_page \|\| !mips_frame_info_initialized)
1da177e4	413	return 0;
dc953df1	414
1da177e4 LT	415	pc = thread_saved_pc(p);
1da177e4 LT	416	if (!in_sched_functions(pc))
dc953df1	417	return pc;
1da177e4	418
1da177e4	419	frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
dc953df1 TS	420	do {
dc953df1 TS	421	int i;
1da177e4	422
dc953df1 TS	423	if (frame < stack_page \|\| frame > stack_page + THREAD_SIZE - 32)
dc953df1 TS	424	return 0;
1da177e4	425
dc953df1 TS	426	for (i = ARRAY_SIZE(mfinfo) - 1; i >= 0; i--) {
	427	if (pc >= (unsigned long) mfinfo[i].func)
	428	break;
	429	}
	430	if (i < 0)
	431	break;
1da177e4	432
dc953df1 TS	433	if (mfinfo[i].omit_fp)
	434	break;
	435	pc = ((unsigned long *)frame)[mfinfo[i].pc_offset];
	436	frame = ((unsigned long *)frame)[mfinfo[i].frame_offset];
	437	} while (in_sched_functions(pc));
1da177e4 LT	438
	439	return pc;
	440	}
	441
	442	EXPORT_SYMBOL(get_wchan);