[mirror_ubuntu-jammy-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 <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);

	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 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_size = 0;
	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 (info->func_size && i >= info->func_size / 4)
			break;
		if (
#ifdef CONFIG_32BIT
		    ip->i_format.opcode == addiu_op &&
#endif
#ifdef CONFIG_64BIT
		    ip->i_format.opcode == daddiu_op &&
#endif
		    ip->i_format.rs == 29 &&
		    ip->i_format.rt == 29) {
			/* addiu/daddiu sp,sp,-imm */
			if (info->frame_size)
				continue;
			info->frame_size = - ip->i_format.simmediate;
		}

		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 &&
		    ip->i_format.rt == 31) {
			/* sw / sd $ra, offset($sp) */
			if (info->pc_offset != -1)
				continue;
			info->pc_offset =
				ip->i_format.simmediate / sizeof(long);
		}
	}
	if (info->pc_offset == -1 || info->frame_size == 0) {
		if (func == schedule)
			printk("Can't analyze prologue code at %p\n", func);
		info->pc_offset = -1;
		info->frame_size = 0;
	}

	return 0;
}

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]);

	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;

		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;
}
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>
63077519	28	#include <linux/kallsyms.h>
1da177e4	29
e50c0a8f	30	#include <asm/abi.h>
1da177e4 LT	31	#include <asm/bootinfo.h>
1da177e4 LT	32	#include <asm/cpu.h>
e50c0a8f	33	#include <asm/dsp.h>
1da177e4 LT	34	#include <asm/fpu.h>
	35	#include <asm/pgtable.h>
	36	#include <asm/system.h>
	37	#include <asm/mipsregs.h>
	38	#include <asm/processor.h>
	39	#include <asm/uaccess.h>
	40	#include <asm/io.h>
	41	#include <asm/elf.h>
	42	#include <asm/isadep.h>
	43	#include <asm/inst.h>
41c594ab RB	44	#ifdef CONFIG_MIPS_MT_SMTC
	45	#include <asm/mipsmtregs.h>
	46	extern void smtc_idle_loop_hook(void);
	47	#endif /* CONFIG_MIPS_MT_SMTC */
1da177e4	48
1da177e4 LT	49	/*
	50	* The idle thread. There's no useful work to be done, so just try to conserve
	51	* power and have a low exit latency (ie sit in a loop waiting for somebody to
	52	* say that they'd like to reschedule)
	53	*/
	54	ATTRIB_NORET void cpu_idle(void)
	55	{
	56	/* endless idle loop with no priority at all */
	57	while (1) {
41c594ab RB	58	while (!need_resched()) {
	59	#ifdef CONFIG_MIPS_MT_SMTC
	60	smtc_idle_loop_hook();
	61	#endif /* CONFIG_MIPS_MT_SMTC */
1da177e4 LT	62	if (cpu_wait)
1da177e4 LT	63	(*cpu_wait)();
41c594ab	64	}
5bfb5d69	65	preempt_enable_no_resched();
1da177e4	66	schedule();
5bfb5d69	67	preempt_disable();
1da177e4 LT	68	}
	69	}
	70
e50c0a8f RB	71	/*
	72	* Native o32 and N64 ABI without DSP ASE
	73	*/
e50c0a8f RB	74	struct mips_abi mips_abi = {
	75	.do_signal = do_signal,
	76	#ifdef CONFIG_TRAD_SIGNALS
	77	.setup_frame = setup_frame,
	78	#endif
	79	.setup_rt_frame = setup_rt_frame
	80	};
	81
	82	#ifdef CONFIG_MIPS32_O32
	83	/*
	84	* o32 compatibility on 64-bit kernels, without DSP ASE
	85	*/
e50c0a8f RB	86	struct mips_abi mips_abi_32 = {
	87	.do_signal = do_signal32,
	88	.setup_frame = setup_frame_32,
	89	.setup_rt_frame = setup_rt_frame_32
	90	};
	91	#endif /* CONFIG_MIPS32_O32 */
	92
	93	#ifdef CONFIG_MIPS32_N32
	94	/*
	95	* N32 on 64-bit kernels, without DSP ASE
	96	*/
e50c0a8f RB	97	struct mips_abi mips_abi_n32 = {
	98	.do_signal = do_signal,
	99	.setup_rt_frame = setup_rt_frame_n32
	100	};
	101	#endif /* CONFIG_MIPS32_N32 */
	102
1da177e4 LT	103	asmlinkage void ret_from_fork(void);
	104
	105	void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
	106	{
	107	unsigned long status;
	108
	109	/* New thread loses kernel privileges. */
	110	status = regs->cp0_status & ~(ST0_CU0\|ST0_CU1\|KU_MASK);
875d43e7	111	#ifdef CONFIG_64BIT
1da177e4 LT	112	status &= ~ST0_FR;
	113	status \|= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR;
	114	#endif
	115	status \|= KU_USER;
	116	regs->cp0_status = status;
	117	clear_used_math();
	118	lose_fpu();
e50c0a8f RB	119	if (cpu_has_dsp)
e50c0a8f RB	120	__init_dsp();
1da177e4 LT	121	regs->cp0_epc = pc;
	122	regs->regs[29] = sp;
	123	current_thread_info()->addr_limit = USER_DS;
	124	}
	125
	126	void exit_thread(void)
	127	{
	128	}
	129
	130	void flush_thread(void)
	131	{
	132	}
	133
	134	int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
	135	unsigned long unused, struct task_struct p, struct pt_regs regs)
	136	{
75bb07e7	137	struct thread_info *ti = task_thread_info(p);
1da177e4 LT	138	struct pt_regs *childregs;
1da177e4 LT	139	long childksp;
3c37026d	140	p->set_child_tid = p->clear_child_tid = NULL;
1da177e4	141
75bb07e7	142	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
1da177e4 LT	143
	144	preempt_disable();
	145
e50c0a8f	146	if (is_fpu_owner())
1da177e4	147	save_fp(p);
e50c0a8f RB	148
	149	if (cpu_has_dsp)
	150	save_dsp(p);
1da177e4 LT	151
	152	preempt_enable();
	153
	154	/* set up new TSS. */
	155	childregs = (struct pt_regs *) childksp - 1;
	156	childregs = regs;
	157	childregs->regs[7] = 0; /* Clear error flag */
	158
	159	#if defined(CONFIG_BINFMT_IRIX)
	160	if (current->personality != PER_LINUX) {
	161	/* Under IRIX things are a little different. */
	162	childregs->regs[3] = 1;
	163	regs->regs[3] = 0;
	164	}
	165	#endif
	166	childregs->regs[2] = 0; /* Child gets zero as return value */
	167	regs->regs[2] = p->pid;
	168
	169	if (childregs->cp0_status & ST0_CU0) {
	170	childregs->regs[28] = (unsigned long) ti;
	171	childregs->regs[29] = childksp;
	172	ti->addr_limit = KERNEL_DS;
	173	} else {
	174	childregs->regs[29] = usp;
	175	ti->addr_limit = USER_DS;
	176	}
	177	p->thread.reg29 = (unsigned long) childregs;
	178	p->thread.reg31 = (unsigned long) ret_from_fork;
	179
	180	/*
	181	* New tasks lose permission to use the fpu. This accelerates context
	182	* switching for most programs since they don't use the fpu.
	183	*/
	184	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2\|ST0_CU1);
	185	childregs->cp0_status &= ~(ST0_CU2\|ST0_CU1);
	186	clear_tsk_thread_flag(p, TIF_USEDFPU);
	187
3c37026d RB	188	if (clone_flags & CLONE_SETTLS)
	189	ti->tp_value = regs->regs[7];
	190
1da177e4 LT	191	return 0;
	192	}
	193
	194	/* Fill in the fpu structure for a core dump.. */
	195	int dump_fpu(struct pt_regs regs, elf_fpregset_t r)
	196	{
	197	memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));
	198
	199	return 1;
	200	}
	201
d56efda4	202	void elf_dump_regs(elf_greg_t gp, struct pt_regs regs)
1da177e4 LT	203	{
	204	int i;
	205
	206	for (i = 0; i < EF_R0; i++)
	207	gp[i] = 0;
	208	gp[EF_R0] = 0;
	209	for (i = 1; i <= 31; i++)
	210	gp[EF_R0 + i] = regs->regs[i];
	211	gp[EF_R26] = 0;
	212	gp[EF_R27] = 0;
	213	gp[EF_LO] = regs->lo;
	214	gp[EF_HI] = regs->hi;
	215	gp[EF_CP0_EPC] = regs->cp0_epc;
	216	gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
	217	gp[EF_CP0_STATUS] = regs->cp0_status;
	218	gp[EF_CP0_CAUSE] = regs->cp0_cause;
	219	#ifdef EF_UNUSED0
	220	gp[EF_UNUSED0] = 0;
	221	#endif
	222	}
	223
71e0e556 RB	224	int dump_task_regs (struct task_struct tsk, elf_gregset_t regs)
71e0e556 RB	225	{
40bc9c67	226	elf_dump_regs(*regs, task_pt_regs(tsk));
71e0e556 RB	227	return 1;
	228	}
	229
1da177e4 LT	230	int dump_task_fpu (struct task_struct t, elf_fpregset_t fpr)
	231	{
	232	memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
	233
	234	return 1;
	235	}
	236
	237	/*
	238	* Create a kernel thread
	239	*/
	240	ATTRIB_NORET void kernel_thread_helper(void arg, int (fn)(void *))
	241	{
	242	do_exit(fn(arg));
	243	}
	244
	245	long kernel_thread(int (fn)(void ), void *arg, unsigned long flags)
	246	{
	247	struct pt_regs regs;
	248
	249	memset(&regs, 0, sizeof(regs));
	250
	251	regs.regs[4] = (unsigned long) arg;
	252	regs.regs[5] = (unsigned long) fn;
	253	regs.cp0_epc = (unsigned long) kernel_thread_helper;
	254	regs.cp0_status = read_c0_status();
	255	#if defined(CONFIG_CPU_R3000) \|\| defined(CONFIG_CPU_TX39XX)
	256	regs.cp0_status &= ~(ST0_KUP \| ST0_IEC);
	257	regs.cp0_status \|= ST0_IEP;
	258	#else
	259	regs.cp0_status \|= ST0_EXL;
	260	#endif
	261
	262	/* Ok, create the new process.. */
	263	return do_fork(flags \| CLONE_VM \| CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
	264	}
	265
dc953df1 TS	266	static struct mips_frame_info {
dc953df1 TS	267	void *func;
63077519 AN	268	unsigned long func_size;
63077519 AN	269	int frame_size;
1da177e4	270	int pc_offset;
63077519 AN	271	} *schedule_frame, mfinfo[64];
63077519 AN	272	static int mfinfo_num;
dc953df1	273
dc953df1	274	static int __init get_frame_info(struct mips_frame_info *info)
1da177e4 LT	275	{
1da177e4 LT	276	int i;
dc953df1	277	void *func = info->func;
1da177e4 LT	278	union mips_instruction ip = (union mips_instruction )func;
1da177e4 LT	279	info->pc_offset = -1;
63077519	280	info->frame_size = 0;
1da177e4 LT	281	for (i = 0; i < 128; i++, ip++) {
	282	/* if jal, jalr, jr, stop. */
	283	if (ip->j_format.opcode == jal_op \|\|
	284	(ip->r_format.opcode == spec_op &&
	285	(ip->r_format.func == jalr_op \|\|
	286	ip->r_format.func == jr_op)))
	287	break;
	288
63077519 AN	289	if (info->func_size && i >= info->func_size / 4)
	290	break;
	291	if (
	292	#ifdef CONFIG_32BIT
	293	ip->i_format.opcode == addiu_op &&
	294	#endif
	295	#ifdef CONFIG_64BIT
	296	ip->i_format.opcode == daddiu_op &&
	297	#endif
	298	ip->i_format.rs == 29 &&
	299	ip->i_format.rt == 29) {
	300	/* addiu/daddiu sp,sp,-imm */
	301	if (info->frame_size)
	302	continue;
	303	info->frame_size = - ip->i_format.simmediate;
	304	}
	305
1da177e4	306	if (
875d43e7	307	#ifdef CONFIG_32BIT
1da177e4 LT	308	ip->i_format.opcode == sw_op &&
1da177e4 LT	309	#endif
875d43e7	310	#ifdef CONFIG_64BIT
1da177e4 LT	311	ip->i_format.opcode == sd_op &&
1da177e4 LT	312	#endif
63077519 AN	313	ip->i_format.rs == 29 &&
63077519 AN	314	ip->i_format.rt == 31) {
1da177e4	315	/* sw / sd $ra, offset($sp) */
63077519 AN	316	if (info->pc_offset != -1)
	317	continue;
	318	info->pc_offset =
	319	ip->i_format.simmediate / sizeof(long);
1da177e4 LT	320	}
1da177e4 LT	321	}
63077519 AN	322	if (info->pc_offset == -1 \|\| info->frame_size == 0) {
	323	if (func == schedule)
	324	printk("Can't analyze prologue code at %p\n", func);
1da177e4	325	info->pc_offset = -1;
63077519	326	info->frame_size = 0;
1da177e4 LT	327	}
	328
	329	return 0;
	330	}
	331
	332	static int __init frame_info_init(void)
	333	{
63077519 AN	334	int i;
	335	#ifdef CONFIG_KALLSYMS
	336	char *modname;
	337	char namebuf[KSYM_NAME_LEN + 1];
	338	unsigned long start, size, ofs;
	339	extern char __sched_text_start[], __sched_text_end[];
	340	extern char __lock_text_start[], __lock_text_end[];
	341
	342	start = (unsigned long)__sched_text_start;
	343	for (i = 0; i < ARRAY_SIZE(mfinfo); i++) {
	344	if (start == (unsigned long)schedule)
	345	schedule_frame = &mfinfo[i];
	346	if (!kallsyms_lookup(start, &size, &ofs, &modname, namebuf))
	347	break;
	348	mfinfo[i].func = (void *)(start + ofs);
	349	mfinfo[i].func_size = size;
	350	start += size - ofs;
	351	if (start >= (unsigned long)__lock_text_end)
	352	break;
	353	if (start == (unsigned long)__sched_text_end)
	354	start = (unsigned long)__lock_text_start;
	355	}
	356	#else
	357	mfinfo[0].func = schedule;
	358	schedule_frame = &mfinfo[0];
	359	#endif
	360	for (i = 0; i < ARRAY_SIZE(mfinfo) && mfinfo[i].func; i++)
	361	get_frame_info(&mfinfo[i]);
	362
	363	mfinfo_num = i;
1da177e4 LT	364	return 0;
	365	}
	366
	367	arch_initcall(frame_info_init);
	368
	369	/*
	370	* Return saved PC of a blocked thread.
	371	*/
	372	unsigned long thread_saved_pc(struct task_struct *tsk)
	373	{
	374	struct thread_struct *t = &tsk->thread;
	375
	376	/* New born processes are a special case */
	377	if (t->reg31 == (unsigned long) ret_from_fork)
	378	return t->reg31;
	379
63077519	380	if (!schedule_frame \|\| schedule_frame->pc_offset < 0)
1da177e4	381	return 0;
63077519	382	return ((unsigned long *)t->reg29)[schedule_frame->pc_offset];
1da177e4 LT	383	}
	384
	385	/* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */
	386	unsigned long get_wchan(struct task_struct *p)
	387	{
dc953df1	388	unsigned long stack_page;
63077519 AN	389	unsigned long pc;
	390	#ifdef CONFIG_KALLSYMS
	391	unsigned long frame;
	392	#endif
1da177e4 LT	393
	394	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	395	return 0;
	396
75bb07e7	397	stack_page = (unsigned long)task_stack_page(p);
63077519	398	if (!stack_page \|\| !mfinfo_num)
1da177e4	399	return 0;
dc953df1	400
1da177e4	401	pc = thread_saved_pc(p);
63077519	402	#ifdef CONFIG_KALLSYMS
1da177e4	403	if (!in_sched_functions(pc))
dc953df1	404	return pc;
1da177e4	405
63077519	406	frame = p->thread.reg29 + schedule_frame->frame_size;
dc953df1 TS	407	do {
dc953df1 TS	408	int i;
1da177e4	409
dc953df1 TS	410	if (frame < stack_page \|\| frame > stack_page + THREAD_SIZE - 32)
dc953df1 TS	411	return 0;
1da177e4	412
63077519	413	for (i = mfinfo_num - 1; i >= 0; i--) {
dc953df1 TS	414	if (pc >= (unsigned long) mfinfo[i].func)
	415	break;
	416	}
	417	if (i < 0)
	418	break;
1da177e4	419
dc953df1	420	pc = ((unsigned long *)frame)[mfinfo[i].pc_offset];
63077519 AN	421	if (!mfinfo[i].frame_size)
	422	break;
	423	frame += mfinfo[i].frame_size;
dc953df1	424	} while (in_sched_functions(pc));
63077519	425	#endif
1da177e4 LT	426
	427	return pc;
	428	}
	429