[deliverable/linux.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/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 <linux/kallsyms.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>
#ifdef CONFIG_MIPS_MT_SMTC
#include <asm/mipsmtregs.h>
extern void smtc_idle_loop_hook(void);
#endif /* CONFIG_MIPS_MT_SMTC */

/*
 * 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()) {
#ifdef CONFIG_MIPS_MT_SMTC
			smtc_idle_loop_hook();
#endif /* CONFIG_MIPS_MT_SMTC */
			if (cpu_wait)
				(*cpu_wait)();
		}
		preempt_enable_no_resched();
		schedule();
		preempt_disable();
	}
}

/*
 * Native o32 and N64 ABI without DSP ASE
 */
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
 */
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
 */
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);

#ifdef CONFIG_MIPS_MT_FPAFF
	/*
	 * FPU affinity support is cleaner if we track the
	 * user-visible CPU affinity from the very beginning.
	 * The generic cpus_allowed mask will already have
	 * been copied from the parent before copy_thread
	 * is invoked.
	 */
	p->thread.user_cpus_allowed = p->cpus_allowed;
#endif /* CONFIG_MIPS_MT_FPAFF */

	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;
	unsigned long func_size;
	int frame_size;
	int pc_offset;
} *schedule_frame, mfinfo[64];
static int mfinfo_num;

static inline int is_ra_save_ins(union mips_instruction *ip)
{
	/* sw / sd $ra, offset($sp) */
	return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
		ip->i_format.rs == 29 &&
		ip->i_format.rt == 31;
}

static inline int is_jal_jalr_jr_ins(union mips_instruction *ip)
{
	if (ip->j_format.opcode == jal_op)
		return 1;
	if (ip->r_format.opcode != spec_op)
		return 0;
	return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
}

static inline int is_sp_move_ins(union mips_instruction *ip)
{
	/* addiu/daddiu sp,sp,-imm */
	if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
		return 0;
	if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
		return 1;
	return 0;
}

static int get_frame_info(struct mips_frame_info *info)
{
	union mips_instruction *ip = info->func;
	int i, max_insns =
		min(128UL, info->func_size / sizeof(union mips_instruction));

	info->pc_offset = -1;
	info->frame_size = 0;

	for (i = 0; i < max_insns; i++, ip++) {

		if (is_jal_jalr_jr_ins(ip))
			break;
		if (is_sp_move_ins(ip)) {
			if (info->frame_size)
				continue;
			info->frame_size = - ip->i_format.simmediate;
		}

		if (is_ra_save_ins(ip)) {
			if (info->pc_offset != -1)
				continue;
			info->pc_offset =
				ip->i_format.simmediate / sizeof(long);
		}
	}
	if (info->frame_size && info->pc_offset >= 0) /* nested */
		return 0;
	if (info->pc_offset < 0) /* leaf */
		return 1;
	/* prologue seems boggus... */
	return -1;
}

static int __init frame_info_init(void)
{
	int i;
#ifdef CONFIG_KALLSYMS
	char *modname;
	char namebuf[KSYM_NAME_LEN + 1];
	unsigned long start, size, ofs;
	extern char __sched_text_start[], __sched_text_end[];
	extern char __lock_text_start[], __lock_text_end[];

	start = (unsigned long)__sched_text_start;
	for (i = 0; i < ARRAY_SIZE(mfinfo); i++) {
		if (start == (unsigned long)schedule)
			schedule_frame = &mfinfo[i];
		if (!kallsyms_lookup(start, &size, &ofs, &modname, namebuf))
			break;
		mfinfo[i].func = (void *)(start + ofs);
		mfinfo[i].func_size = size;
		start += size - ofs;
		if (start >= (unsigned long)__lock_text_end)
			break;
		if (start == (unsigned long)__sched_text_end)
			start = (unsigned long)__lock_text_start;
	}
#else
	mfinfo[0].func = schedule;
	schedule_frame = &mfinfo[0];
#endif
	for (i = 0; i < ARRAY_SIZE(mfinfo) && mfinfo[i].func; i++)
		get_frame_info(mfinfo + i);

	/*
	 * Without schedule() frame info, result given by
	 * thread_saved_pc() and get_wchan() are not reliable.
	 */
	if (schedule_frame->pc_offset < 0)
		printk("Can't analyze schedule() prologue at %p\n", schedule);

	mfinfo_num = i;
	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 || 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 pc;
#ifdef CONFIG_KALLSYMS
	unsigned long frame;
#endif

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

	stack_page = (unsigned long)task_stack_page(p);
	if (!stack_page || !mfinfo_num)
		return 0;

	pc = thread_saved_pc(p);
#ifdef CONFIG_KALLSYMS
	if (!in_sched_functions(pc))
		return pc;

	frame = p->thread.reg29 + schedule_frame->frame_size;
	do {
		int i;

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

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

		if (mfinfo[i].pc_offset < 0)
			break;
		pc = ((unsigned long *)frame)[mfinfo[i].pc_offset];
		if (!mfinfo[i].frame_size)
			break;
		frame += mfinfo[i].frame_size;
	} while (in_sched_functions(pc));
#endif

	return pc;
}

#ifdef CONFIG_KALLSYMS
/* used by show_frametrace() */
unsigned long unwind_stack(struct task_struct *task,
			   unsigned long **sp, unsigned long pc)
{
	unsigned long stack_page;
	struct mips_frame_info info;
	char *modname;
	char namebuf[KSYM_NAME_LEN + 1];
	unsigned long size, ofs;

	stack_page = (unsigned long)task_stack_page(task);
	if (!stack_page)
		return 0;

	if (!kallsyms_lookup(pc, &size, &ofs, &modname, namebuf))
		return 0;
	if (ofs == 0)
		return 0;

	info.func = (void *)(pc - ofs);
	info.func_size = ofs;	/* analyze from start to ofs */
	if (get_frame_info(&info)) {
		/* leaf or unknown */
		*sp += info.frame_size / sizeof(long);
		return 0;
	}
	if ((unsigned long)*sp < stack_page ||
	    (unsigned long)*sp + info.frame_size / sizeof(long) >
	    stack_page + THREAD_SIZE - 32)
		return 0;

	pc = (*sp)[info.pc_offset];
	*sp += info.frame_size / sizeof(long);
	return pc;
}
#endif
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	*/
1da177e4 LT	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>
63077519	27	#include <linux/kallsyms.h>
1da177e4	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>
41c594ab RB	43	#ifdef CONFIG_MIPS_MT_SMTC
	44	#include <asm/mipsmtregs.h>
	45	extern void smtc_idle_loop_hook(void);
	46	#endif /* CONFIG_MIPS_MT_SMTC */
1da177e4	47
1da177e4 LT	48	/*
	49	* The idle thread. There's no useful work to be done, so just try to conserve
	50	* power and have a low exit latency (ie sit in a loop waiting for somebody to
	51	* say that they'd like to reschedule)
	52	*/
	53	ATTRIB_NORET void cpu_idle(void)
	54	{
	55	/* endless idle loop with no priority at all */
	56	while (1) {
41c594ab RB	57	while (!need_resched()) {
	58	#ifdef CONFIG_MIPS_MT_SMTC
	59	smtc_idle_loop_hook();
	60	#endif /* CONFIG_MIPS_MT_SMTC */
1da177e4 LT	61	if (cpu_wait)
1da177e4 LT	62	(*cpu_wait)();
41c594ab	63	}
5bfb5d69	64	preempt_enable_no_resched();
1da177e4	65	schedule();
5bfb5d69	66	preempt_disable();
1da177e4 LT	67	}
	68	}
	69
e50c0a8f RB	70	/*
	71	* Native o32 and N64 ABI without DSP ASE
	72	*/
e50c0a8f RB	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	*/
e50c0a8f RB	85	struct mips_abi mips_abi_32 = {
	86	.do_signal = do_signal32,
	87	.setup_frame = setup_frame_32,
	88	.setup_rt_frame = setup_rt_frame_32
	89	};
	90	#endif /* CONFIG_MIPS32_O32 */
	91
	92	#ifdef CONFIG_MIPS32_N32
	93	/*
	94	* N32 on 64-bit kernels, without DSP ASE
	95	*/
e50c0a8f RB	96	struct mips_abi mips_abi_n32 = {
	97	.do_signal = do_signal,
	98	.setup_rt_frame = setup_rt_frame_n32
	99	};
	100	#endif /* CONFIG_MIPS32_N32 */
	101
1da177e4 LT	102	asmlinkage void ret_from_fork(void);
	103
	104	void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
	105	{
	106	unsigned long status;
	107
	108	/* New thread loses kernel privileges. */
	109	status = regs->cp0_status & ~(ST0_CU0\|ST0_CU1\|KU_MASK);
875d43e7	110	#ifdef CONFIG_64BIT
1da177e4 LT	111	status &= ~ST0_FR;
	112	status \|= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR;
	113	#endif
	114	status \|= KU_USER;
	115	regs->cp0_status = status;
	116	clear_used_math();
	117	lose_fpu();
e50c0a8f RB	118	if (cpu_has_dsp)
e50c0a8f RB	119	__init_dsp();
1da177e4 LT	120	regs->cp0_epc = pc;
	121	regs->regs[29] = sp;
	122	current_thread_info()->addr_limit = USER_DS;
	123	}
	124
	125	void exit_thread(void)
	126	{
	127	}
	128
	129	void flush_thread(void)
	130	{
	131	}
	132
	133	int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
	134	unsigned long unused, struct task_struct p, struct pt_regs regs)
	135	{
75bb07e7	136	struct thread_info *ti = task_thread_info(p);
1da177e4 LT	137	struct pt_regs *childregs;
1da177e4 LT	138	long childksp;
3c37026d	139	p->set_child_tid = p->clear_child_tid = NULL;
1da177e4	140
75bb07e7	141	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
1da177e4 LT	142
	143	preempt_disable();
	144
e50c0a8f	145	if (is_fpu_owner())
1da177e4	146	save_fp(p);
e50c0a8f RB	147
	148	if (cpu_has_dsp)
	149	save_dsp(p);
1da177e4 LT	150
	151	preempt_enable();
	152
	153	/* set up new TSS. */
	154	childregs = (struct pt_regs *) childksp - 1;
	155	childregs = regs;
	156	childregs->regs[7] = 0; /* Clear error flag */
	157
	158	#if defined(CONFIG_BINFMT_IRIX)
	159	if (current->personality != PER_LINUX) {
	160	/* Under IRIX things are a little different. */
	161	childregs->regs[3] = 1;
	162	regs->regs[3] = 0;
	163	}
	164	#endif
	165	childregs->regs[2] = 0; /* Child gets zero as return value */
	166	regs->regs[2] = p->pid;
	167
	168	if (childregs->cp0_status & ST0_CU0) {
	169	childregs->regs[28] = (unsigned long) ti;
	170	childregs->regs[29] = childksp;
	171	ti->addr_limit = KERNEL_DS;
	172	} else {
	173	childregs->regs[29] = usp;
	174	ti->addr_limit = USER_DS;
	175	}
	176	p->thread.reg29 = (unsigned long) childregs;
	177	p->thread.reg31 = (unsigned long) ret_from_fork;
	178
	179	/*
	180	* New tasks lose permission to use the fpu. This accelerates context
	181	* switching for most programs since they don't use the fpu.
	182	*/
	183	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2\|ST0_CU1);
	184	childregs->cp0_status &= ~(ST0_CU2\|ST0_CU1);
	185	clear_tsk_thread_flag(p, TIF_USEDFPU);
	186
f088fc84 RB	187	#ifdef CONFIG_MIPS_MT_FPAFF
	188	/*
	189	* FPU affinity support is cleaner if we track the
	190	* user-visible CPU affinity from the very beginning.
	191	* The generic cpus_allowed mask will already have
	192	* been copied from the parent before copy_thread
	193	* is invoked.
	194	*/
	195	p->thread.user_cpus_allowed = p->cpus_allowed;
	196	#endif /* CONFIG_MIPS_MT_FPAFF */
	197
3c37026d RB	198	if (clone_flags & CLONE_SETTLS)
	199	ti->tp_value = regs->regs[7];
	200
1da177e4 LT	201	return 0;
	202	}
	203
	204	/* Fill in the fpu structure for a core dump.. */
	205	int dump_fpu(struct pt_regs regs, elf_fpregset_t r)
	206	{
	207	memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));
	208
	209	return 1;
	210	}
	211
d56efda4	212	void elf_dump_regs(elf_greg_t gp, struct pt_regs regs)
1da177e4 LT	213	{
	214	int i;
	215
	216	for (i = 0; i < EF_R0; i++)
	217	gp[i] = 0;
	218	gp[EF_R0] = 0;
	219	for (i = 1; i <= 31; i++)
	220	gp[EF_R0 + i] = regs->regs[i];
	221	gp[EF_R26] = 0;
	222	gp[EF_R27] = 0;
	223	gp[EF_LO] = regs->lo;
	224	gp[EF_HI] = regs->hi;
	225	gp[EF_CP0_EPC] = regs->cp0_epc;
	226	gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
	227	gp[EF_CP0_STATUS] = regs->cp0_status;
	228	gp[EF_CP0_CAUSE] = regs->cp0_cause;
	229	#ifdef EF_UNUSED0
	230	gp[EF_UNUSED0] = 0;
	231	#endif
	232	}
	233
71e0e556 RB	234	int dump_task_regs (struct task_struct tsk, elf_gregset_t regs)
71e0e556 RB	235	{
40bc9c67	236	elf_dump_regs(*regs, task_pt_regs(tsk));
71e0e556 RB	237	return 1;
	238	}
	239
1da177e4 LT	240	int dump_task_fpu (struct task_struct t, elf_fpregset_t fpr)
	241	{
	242	memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
	243
	244	return 1;
	245	}
	246
	247	/*
	248	* Create a kernel thread
	249	*/
	250	ATTRIB_NORET void kernel_thread_helper(void arg, int (fn)(void *))
	251	{
	252	do_exit(fn(arg));
	253	}
	254
	255	long kernel_thread(int (fn)(void ), void *arg, unsigned long flags)
	256	{
	257	struct pt_regs regs;
	258
	259	memset(&regs, 0, sizeof(regs));
	260
	261	regs.regs[4] = (unsigned long) arg;
	262	regs.regs[5] = (unsigned long) fn;
	263	regs.cp0_epc = (unsigned long) kernel_thread_helper;
	264	regs.cp0_status = read_c0_status();
	265	#if defined(CONFIG_CPU_R3000) \|\| defined(CONFIG_CPU_TX39XX)
	266	regs.cp0_status &= ~(ST0_KUP \| ST0_IEC);
	267	regs.cp0_status \|= ST0_IEP;
	268	#else
	269	regs.cp0_status \|= ST0_EXL;
	270	#endif
	271
	272	/* Ok, create the new process.. */
	273	return do_fork(flags \| CLONE_VM \| CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
	274	}
	275
dc953df1 TS	276	static struct mips_frame_info {
dc953df1 TS	277	void *func;
63077519 AN	278	unsigned long func_size;
63077519 AN	279	int frame_size;
1da177e4	280	int pc_offset;
63077519 AN	281	} *schedule_frame, mfinfo[64];
63077519 AN	282	static int mfinfo_num;
dc953df1	283
c0efbb6d FBH	284	static inline int is_ra_save_ins(union mips_instruction *ip)
	285	{
	286	/* sw / sd $ra, offset($sp) */
	287	return (ip->i_format.opcode == sw_op \|\| ip->i_format.opcode == sd_op) &&
	288	ip->i_format.rs == 29 &&
	289	ip->i_format.rt == 31;
	290	}
	291
	292	static inline int is_jal_jalr_jr_ins(union mips_instruction *ip)
	293	{
	294	if (ip->j_format.opcode == jal_op)
	295	return 1;
	296	if (ip->r_format.opcode != spec_op)
	297	return 0;
	298	return ip->r_format.func == jalr_op \|\| ip->r_format.func == jr_op;
	299	}
	300
	301	static inline int is_sp_move_ins(union mips_instruction *ip)
	302	{
	303	/* addiu/daddiu sp,sp,-imm */
	304	if (ip->i_format.rs != 29 \|\| ip->i_format.rt != 29)
	305	return 0;
	306	if (ip->i_format.opcode == addiu_op \|\| ip->i_format.opcode == daddiu_op)
	307	return 1;
	308	return 0;
	309	}
	310
f66686f7	311	static int get_frame_info(struct mips_frame_info *info)
1da177e4	312	{
c0efbb6d FBH	313	union mips_instruction *ip = info->func;
	314	int i, max_insns =
	315	min(128UL, info->func_size / sizeof(union mips_instruction));
	316
1da177e4	317	info->pc_offset = -1;
63077519	318	info->frame_size = 0;
1da177e4	319
c0efbb6d FBH	320	for (i = 0; i < max_insns; i++, ip++) {
	321
	322	if (is_jal_jalr_jr_ins(ip))
63077519	323	break;
c0efbb6d	324	if (is_sp_move_ins(ip)) {
63077519 AN	325	if (info->frame_size)
	326	continue;
	327	info->frame_size = - ip->i_format.simmediate;
	328	}
	329
c0efbb6d	330	if (is_ra_save_ins(ip)) {
63077519 AN	331	if (info->pc_offset != -1)
	332	continue;
	333	info->pc_offset =
	334	ip->i_format.simmediate / sizeof(long);
1da177e4 LT	335	}
1da177e4 LT	336	}
f66686f7 AN	337	if (info->frame_size && info->pc_offset >= 0) /* nested */
	338	return 0;
	339	if (info->pc_offset < 0) /* leaf */
	340	return 1;
	341	/* prologue seems boggus... */
	342	return -1;
1da177e4 LT	343	}
	344
	345	static int __init frame_info_init(void)
	346	{
63077519 AN	347	int i;
	348	#ifdef CONFIG_KALLSYMS
	349	char *modname;
	350	char namebuf[KSYM_NAME_LEN + 1];
	351	unsigned long start, size, ofs;
	352	extern char __sched_text_start[], __sched_text_end[];
	353	extern char __lock_text_start[], __lock_text_end[];
	354
	355	start = (unsigned long)__sched_text_start;
	356	for (i = 0; i < ARRAY_SIZE(mfinfo); i++) {
	357	if (start == (unsigned long)schedule)
	358	schedule_frame = &mfinfo[i];
	359	if (!kallsyms_lookup(start, &size, &ofs, &modname, namebuf))
	360	break;
	361	mfinfo[i].func = (void *)(start + ofs);
	362	mfinfo[i].func_size = size;
	363	start += size - ofs;
	364	if (start >= (unsigned long)__lock_text_end)
	365	break;
	366	if (start == (unsigned long)__sched_text_end)
	367	start = (unsigned long)__lock_text_start;
	368	}
	369	#else
	370	mfinfo[0].func = schedule;
	371	schedule_frame = &mfinfo[0];
	372	#endif
6057a798 FBH	373	for (i = 0; i < ARRAY_SIZE(mfinfo) && mfinfo[i].func; i++)
	374	get_frame_info(mfinfo + i);
	375
	376	/*
	377	* Without schedule() frame info, result given by
	378	* thread_saved_pc() and get_wchan() are not reliable.
	379	*/
	380	if (schedule_frame->pc_offset < 0)
	381	printk("Can't analyze schedule() prologue at %p\n", schedule);
63077519 AN	382
63077519 AN	383	mfinfo_num = i;
1da177e4 LT	384	return 0;
	385	}
	386
	387	arch_initcall(frame_info_init);
	388
	389	/*
	390	* Return saved PC of a blocked thread.
	391	*/
	392	unsigned long thread_saved_pc(struct task_struct *tsk)
	393	{
	394	struct thread_struct *t = &tsk->thread;
	395
	396	/* New born processes are a special case */
	397	if (t->reg31 == (unsigned long) ret_from_fork)
	398	return t->reg31;
	399
63077519	400	if (!schedule_frame \|\| schedule_frame->pc_offset < 0)
1da177e4	401	return 0;
63077519	402	return ((unsigned long *)t->reg29)[schedule_frame->pc_offset];
1da177e4 LT	403	}
	404
	405	/* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */
	406	unsigned long get_wchan(struct task_struct *p)
	407	{
dc953df1	408	unsigned long stack_page;
63077519 AN	409	unsigned long pc;
	410	#ifdef CONFIG_KALLSYMS
	411	unsigned long frame;
	412	#endif
1da177e4 LT	413
	414	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	415	return 0;
	416
75bb07e7	417	stack_page = (unsigned long)task_stack_page(p);
63077519	418	if (!stack_page \|\| !mfinfo_num)
1da177e4	419	return 0;
dc953df1	420
1da177e4	421	pc = thread_saved_pc(p);
63077519	422	#ifdef CONFIG_KALLSYMS
1da177e4	423	if (!in_sched_functions(pc))
dc953df1	424	return pc;
1da177e4	425
63077519	426	frame = p->thread.reg29 + schedule_frame->frame_size;
dc953df1 TS	427	do {
dc953df1 TS	428	int i;
1da177e4	429
dc953df1 TS	430	if (frame < stack_page \|\| frame > stack_page + THREAD_SIZE - 32)
dc953df1 TS	431	return 0;
1da177e4	432
63077519	433	for (i = mfinfo_num - 1; i >= 0; i--) {
dc953df1 TS	434	if (pc >= (unsigned long) mfinfo[i].func)
	435	break;
	436	}
	437	if (i < 0)
	438	break;
1da177e4	439
f66686f7 AN	440	if (mfinfo[i].pc_offset < 0)
f66686f7 AN	441	break;
dc953df1	442	pc = ((unsigned long *)frame)[mfinfo[i].pc_offset];
63077519 AN	443	if (!mfinfo[i].frame_size)
	444	break;
	445	frame += mfinfo[i].frame_size;
dc953df1	446	} while (in_sched_functions(pc));
63077519	447	#endif
1da177e4 LT	448
	449	return pc;
	450	}
	451
f66686f7 AN	452	#ifdef CONFIG_KALLSYMS
	453	/* used by show_frametrace() */
	454	unsigned long unwind_stack(struct task_struct *task,
	455	unsigned long **sp, unsigned long pc)
	456	{
	457	unsigned long stack_page;
	458	struct mips_frame_info info;
	459	char *modname;
	460	char namebuf[KSYM_NAME_LEN + 1];
	461	unsigned long size, ofs;
	462
	463	stack_page = (unsigned long)task_stack_page(task);
	464	if (!stack_page)
	465	return 0;
	466
	467	if (!kallsyms_lookup(pc, &size, &ofs, &modname, namebuf))
	468	return 0;
	469	if (ofs == 0)
	470	return 0;
	471
	472	info.func = (void *)(pc - ofs);
	473	info.func_size = ofs; /* analyze from start to ofs */
	474	if (get_frame_info(&info)) {
	475	/* leaf or unknown */
	476	*sp += info.frame_size / sizeof(long);
	477	return 0;
	478	}
	479	if ((unsigned long)*sp < stack_page \|\|
	480	(unsigned long)*sp + info.frame_size / sizeof(long) >
	481	stack_page + THREAD_SIZE - 32)
	482	return 0;
	483
	484	pc = (*sp)[info.pc_offset];
	485	*sp += info.frame_size / sizeof(long);
	486	return pc;
	487	}
	488	#endif