[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) 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/tick.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 <linux/random.h>

#include <asm/asm.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>
#include <asm/stacktrace.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)
 */
void __noreturn cpu_idle(void)
{
	/* endless idle loop with no priority at all */
	while (1) {
		tick_nohz_stop_sched_tick();
		while (!need_resched()) {
#ifdef CONFIG_SMTC_IDLE_HOOK_DEBUG
			extern void smtc_idle_loop_hook(void);

			smtc_idle_loop_hook();
#endif
			if (cpu_wait)
				(*cpu_wait)();
		}
		tick_nohz_restart_sched_tick();
		preempt_enable_no_resched();
		schedule();
		preempt_disable();
	}
}

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|ST0_FR|KU_MASK);
#ifdef CONFIG_64BIT
	status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR;
#endif
	status |= KU_USER;
	regs->cp0_status = status;
	clear_used_math();
	clear_fpu_owner();
	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
 */
static void __noreturn 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 = (regs.cp0_status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
			  ((regs.cp0_status & (ST0_KUC | ST0_IEC)) << 2);
#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);
}

/*
 *
 */
struct mips_frame_info {
	void		*func;
	unsigned long	func_size;
	int		frame_size;
	int		pc_offset;
};

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;
	unsigned max_insns = info->func_size / sizeof(union mips_instruction);
	unsigned i;

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

	if (!ip)
		goto err;

	if (max_insns == 0)
		max_insns = 128U;	/* unknown function size */
	max_insns = min(128U, max_insns);

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

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

static struct mips_frame_info schedule_mfi __read_mostly;

static int __init frame_info_init(void)
{
	unsigned long size = 0;
#ifdef CONFIG_KALLSYMS
	unsigned long ofs;

	kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs);
#endif
	schedule_mfi.func = schedule;
	schedule_mfi.func_size = size;

	get_frame_info(&schedule_mfi);

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

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


#ifdef CONFIG_KALLSYMS
/* used by show_backtrace() */
unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
			   unsigned long pc, unsigned long *ra)
{
	unsigned long stack_page;
	struct mips_frame_info info;
	unsigned long size, ofs;
	int leaf;
	extern void ret_from_irq(void);
	extern void ret_from_exception(void);

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

	/*
	 * If we reached the bottom of interrupt context,
	 * return saved pc in pt_regs.
	 */
	if (pc == (unsigned long)ret_from_irq ||
	    pc == (unsigned long)ret_from_exception) {
		struct pt_regs *regs;
		if (*sp >= stack_page &&
		    *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
			regs = (struct pt_regs *)*sp;
			pc = regs->cp0_epc;
			if (__kernel_text_address(pc)) {
				*sp = regs->regs[29];
				*ra = regs->regs[31];
				return pc;
			}
		}
		return 0;
	}
	if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
		return 0;
	/*
	 * Return ra if an exception occured at the first instruction
	 */
	if (unlikely(ofs == 0)) {
		pc = *ra;
		*ra = 0;
		return pc;
	}

	info.func = (void *)(pc - ofs);
	info.func_size = ofs;	/* analyze from start to ofs */
	leaf = get_frame_info(&info);
	if (leaf < 0)
		return 0;

	if (*sp < stack_page ||
	    *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
		return 0;

	if (leaf)
		/*
		 * For some extreme cases, get_frame_info() can
		 * consider wrongly a nested function as a leaf
		 * one. In that cases avoid to return always the
		 * same value.
		 */
		pc = pc != *ra ? *ra : 0;
	else
		pc = ((unsigned long *)(*sp))[info.pc_offset];

	*sp += info.frame_size;
	*ra = 0;
	return __kernel_text_address(pc) ? pc : 0;
}
#endif

/*
 * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
 */
unsigned long get_wchan(struct task_struct *task)
{
	unsigned long pc = 0;
#ifdef CONFIG_KALLSYMS
	unsigned long sp;
	unsigned long ra = 0;
#endif

	if (!task || task == current || task->state == TASK_RUNNING)
		goto out;
	if (!task_stack_page(task))
		goto out;

	pc = thread_saved_pc(task);

#ifdef CONFIG_KALLSYMS
	sp = task->thread.reg29 + schedule_mfi.frame_size;

	while (in_sched_functions(pc))
		pc = unwind_stack(task, &sp, pc, &ra);
#endif

out:
	return pc;
}

/*
 * Don't forget that the stack pointer must be aligned on a 8 bytes
 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
 */
unsigned long arch_align_stack(unsigned long sp)
{
	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
		sp -= get_random_int() & ~PAGE_MASK;

	return sp & ALMASK;
}
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>
7bcf7717	14	#include <linux/tick.h>
1da177e4 LT	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>
94109102	29	#include <linux/random.h>
1da177e4	30
94109102	31	#include <asm/asm.h>
1da177e4 LT	32	#include <asm/bootinfo.h>
1da177e4 LT	33	#include <asm/cpu.h>
e50c0a8f	34	#include <asm/dsp.h>
1da177e4 LT	35	#include <asm/fpu.h>
	36	#include <asm/pgtable.h>
	37	#include <asm/system.h>
	38	#include <asm/mipsregs.h>
	39	#include <asm/processor.h>
	40	#include <asm/uaccess.h>
	41	#include <asm/io.h>
	42	#include <asm/elf.h>
	43	#include <asm/isadep.h>
	44	#include <asm/inst.h>
1df0f0ff	45	#include <asm/stacktrace.h>
1da177e4	46
1da177e4 LT	47	/*
	48	* The idle thread. There's no useful work to be done, so just try to conserve
	49	* power and have a low exit latency (ie sit in a loop waiting for somebody to
	50	* say that they'd like to reschedule)
	51	*/
b3f6df9f	52	void __noreturn cpu_idle(void)
1da177e4 LT	53	{
	54	/* endless idle loop with no priority at all */
	55	while (1) {
7bcf7717	56	tick_nohz_stop_sched_tick();
41c594ab	57	while (!need_resched()) {
c68644d3	58	#ifdef CONFIG_SMTC_IDLE_HOOK_DEBUG
447deafb RB	59	extern void smtc_idle_loop_hook(void);
447deafb RB	60
41c594ab	61	smtc_idle_loop_hook();
c68644d3	62	#endif
1da177e4 LT	63	if (cpu_wait)
1da177e4 LT	64	(*cpu_wait)();
41c594ab	65	}
7bcf7717	66	tick_nohz_restart_sched_tick();
5bfb5d69	67	preempt_enable_no_resched();
1da177e4	68	schedule();
5bfb5d69	69	preempt_disable();
1da177e4 LT	70	}
	71	}
	72
	73	asmlinkage void ret_from_fork(void);
	74
	75	void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
	76	{
	77	unsigned long status;
	78
	79	/* New thread loses kernel privileges. */
bbaf238b	80	status = regs->cp0_status & ~(ST0_CU0\|ST0_CU1\|ST0_FR\|KU_MASK);
875d43e7	81	#ifdef CONFIG_64BIT
293c5bd1	82	status \|= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR;
1da177e4 LT	83	#endif
	84	status \|= KU_USER;
	85	regs->cp0_status = status;
	86	clear_used_math();
e04582b7	87	clear_fpu_owner();
e50c0a8f RB	88	if (cpu_has_dsp)
e50c0a8f RB	89	__init_dsp();
1da177e4 LT	90	regs->cp0_epc = pc;
	91	regs->regs[29] = sp;
	92	current_thread_info()->addr_limit = USER_DS;
	93	}
	94
	95	void exit_thread(void)
	96	{
	97	}
	98
	99	void flush_thread(void)
	100	{
	101	}
	102
	103	int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
	104	unsigned long unused, struct task_struct p, struct pt_regs regs)
	105	{
75bb07e7	106	struct thread_info *ti = task_thread_info(p);
1da177e4 LT	107	struct pt_regs *childregs;
1da177e4 LT	108	long childksp;
3c37026d	109	p->set_child_tid = p->clear_child_tid = NULL;
1da177e4	110
75bb07e7	111	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
1da177e4 LT	112
	113	preempt_disable();
	114
e50c0a8f	115	if (is_fpu_owner())
1da177e4	116	save_fp(p);
e50c0a8f RB	117
	118	if (cpu_has_dsp)
	119	save_dsp(p);
1da177e4 LT	120
	121	preempt_enable();
	122
	123	/* set up new TSS. */
	124	childregs = (struct pt_regs *) childksp - 1;
	125	childregs = regs;
	126	childregs->regs[7] = 0; /* Clear error flag */
	127
	128	#if defined(CONFIG_BINFMT_IRIX)
	129	if (current->personality != PER_LINUX) {
	130	/* Under IRIX things are a little different. */
	131	childregs->regs[3] = 1;
	132	regs->regs[3] = 0;
	133	}
	134	#endif
	135	childregs->regs[2] = 0; /* Child gets zero as return value */
	136	regs->regs[2] = p->pid;
	137
	138	if (childregs->cp0_status & ST0_CU0) {
	139	childregs->regs[28] = (unsigned long) ti;
	140	childregs->regs[29] = childksp;
	141	ti->addr_limit = KERNEL_DS;
	142	} else {
	143	childregs->regs[29] = usp;
	144	ti->addr_limit = USER_DS;
	145	}
	146	p->thread.reg29 = (unsigned long) childregs;
	147	p->thread.reg31 = (unsigned long) ret_from_fork;
	148
	149	/*
	150	* New tasks lose permission to use the fpu. This accelerates context
	151	* switching for most programs since they don't use the fpu.
	152	*/
	153	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2\|ST0_CU1);
	154	childregs->cp0_status &= ~(ST0_CU2\|ST0_CU1);
	155	clear_tsk_thread_flag(p, TIF_USEDFPU);
	156
f088fc84 RB	157	#ifdef CONFIG_MIPS_MT_FPAFF
	158	/*
	159	* FPU affinity support is cleaner if we track the
	160	* user-visible CPU affinity from the very beginning.
	161	* The generic cpus_allowed mask will already have
	162	* been copied from the parent before copy_thread
	163	* is invoked.
	164	*/
	165	p->thread.user_cpus_allowed = p->cpus_allowed;
	166	#endif /* CONFIG_MIPS_MT_FPAFF */
	167
3c37026d RB	168	if (clone_flags & CLONE_SETTLS)
	169	ti->tp_value = regs->regs[7];
	170
1da177e4 LT	171	return 0;
	172	}
	173
	174	/* Fill in the fpu structure for a core dump.. */
	175	int dump_fpu(struct pt_regs regs, elf_fpregset_t r)
	176	{
	177	memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));
	178
	179	return 1;
	180	}
	181
d56efda4	182	void elf_dump_regs(elf_greg_t gp, struct pt_regs regs)
1da177e4 LT	183	{
	184	int i;
	185
	186	for (i = 0; i < EF_R0; i++)
	187	gp[i] = 0;
	188	gp[EF_R0] = 0;
	189	for (i = 1; i <= 31; i++)
	190	gp[EF_R0 + i] = regs->regs[i];
	191	gp[EF_R26] = 0;
	192	gp[EF_R27] = 0;
	193	gp[EF_LO] = regs->lo;
	194	gp[EF_HI] = regs->hi;
	195	gp[EF_CP0_EPC] = regs->cp0_epc;
	196	gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
	197	gp[EF_CP0_STATUS] = regs->cp0_status;
	198	gp[EF_CP0_CAUSE] = regs->cp0_cause;
	199	#ifdef EF_UNUSED0
	200	gp[EF_UNUSED0] = 0;
	201	#endif
	202	}
	203
49a89efb	204	int dump_task_regs(struct task_struct tsk, elf_gregset_t regs)
71e0e556	205	{
40bc9c67	206	elf_dump_regs(*regs, task_pt_regs(tsk));
71e0e556 RB	207	return 1;
	208	}
	209
49a89efb	210	int dump_task_fpu(struct task_struct t, elf_fpregset_t fpr)
1da177e4 LT	211	{
	212	memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
	213
	214	return 1;
	215	}
	216
	217	/*
	218	* Create a kernel thread
	219	*/
b3f6df9f	220	static void __noreturn kernel_thread_helper(void arg, int (fn)(void *))
1da177e4 LT	221	{
	222	do_exit(fn(arg));
	223	}
	224
	225	long kernel_thread(int (fn)(void ), void *arg, unsigned long flags)
	226	{
	227	struct pt_regs regs;
	228
	229	memset(&regs, 0, sizeof(regs));
	230
	231	regs.regs[4] = (unsigned long) arg;
	232	regs.regs[5] = (unsigned long) fn;
	233	regs.cp0_epc = (unsigned long) kernel_thread_helper;
	234	regs.cp0_status = read_c0_status();
	235	#if defined(CONFIG_CPU_R3000) \|\| defined(CONFIG_CPU_TX39XX)
e5d77754 MR	236	regs.cp0_status = (regs.cp0_status & ~(ST0_KUP \| ST0_IEP \| ST0_IEC)) \|
e5d77754 MR	237	((regs.cp0_status & (ST0_KUC \| ST0_IEC)) << 2);
1da177e4 LT	238	#else
	239	regs.cp0_status \|= ST0_EXL;
	240	#endif
	241
	242	/* Ok, create the new process.. */
	243	return do_fork(flags \| CLONE_VM \| CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
	244	}
	245
b5943182 FBH	246	/*
	247	*
	248	*/
	249	struct mips_frame_info {
	250	void *func;
	251	unsigned long func_size;
	252	int frame_size;
	253	int pc_offset;
	254	};
dc953df1	255
c0efbb6d FBH	256	static inline int is_ra_save_ins(union mips_instruction *ip)
	257	{
	258	/* sw / sd $ra, offset($sp) */
	259	return (ip->i_format.opcode == sw_op \|\| ip->i_format.opcode == sd_op) &&
	260	ip->i_format.rs == 29 &&
	261	ip->i_format.rt == 31;
	262	}
	263
	264	static inline int is_jal_jalr_jr_ins(union mips_instruction *ip)
	265	{
	266	if (ip->j_format.opcode == jal_op)
	267	return 1;
	268	if (ip->r_format.opcode != spec_op)
	269	return 0;
	270	return ip->r_format.func == jalr_op \|\| ip->r_format.func == jr_op;
	271	}
	272
	273	static inline int is_sp_move_ins(union mips_instruction *ip)
	274	{
	275	/* addiu/daddiu sp,sp,-imm */
	276	if (ip->i_format.rs != 29 \|\| ip->i_format.rt != 29)
	277	return 0;
	278	if (ip->i_format.opcode == addiu_op \|\| ip->i_format.opcode == daddiu_op)
	279	return 1;
	280	return 0;
	281	}
	282
f66686f7	283	static int get_frame_info(struct mips_frame_info *info)
1da177e4	284	{
c0efbb6d	285	union mips_instruction *ip = info->func;
29b376ff FBH	286	unsigned max_insns = info->func_size / sizeof(union mips_instruction);
29b376ff FBH	287	unsigned i;
c0efbb6d	288
1da177e4	289	info->pc_offset = -1;
63077519	290	info->frame_size = 0;
1da177e4	291
29b376ff FBH	292	if (!ip)
	293	goto err;
	294
	295	if (max_insns == 0)
	296	max_insns = 128U; /* unknown function size */
	297	max_insns = min(128U, max_insns);
	298
c0efbb6d FBH	299	for (i = 0; i < max_insns; i++, ip++) {
	300
	301	if (is_jal_jalr_jr_ins(ip))
63077519	302	break;
0cceb4aa FBH	303	if (!info->frame_size) {
	304	if (is_sp_move_ins(ip))
	305	info->frame_size = - ip->i_format.simmediate;
	306	continue;
63077519	307	}
0cceb4aa	308	if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
63077519 AN	309	info->pc_offset =
63077519 AN	310	ip->i_format.simmediate / sizeof(long);
0cceb4aa	311	break;
1da177e4 LT	312	}
1da177e4 LT	313	}
f66686f7 AN	314	if (info->frame_size && info->pc_offset >= 0) /* nested */
	315	return 0;
	316	if (info->pc_offset < 0) /* leaf */
	317	return 1;
	318	/* prologue seems boggus... */
29b376ff	319	err:
f66686f7	320	return -1;
1da177e4 LT	321	}
1da177e4 LT	322
b5943182 FBH	323	static struct mips_frame_info schedule_mfi __read_mostly;
b5943182 FBH	324
1da177e4 LT	325	static int __init frame_info_init(void)
1da177e4 LT	326	{
b5943182	327	unsigned long size = 0;
63077519	328	#ifdef CONFIG_KALLSYMS
b5943182	329	unsigned long ofs;
b5943182	330
55b74283	331	kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs);
63077519	332	#endif
b5943182 FBH	333	schedule_mfi.func = schedule;
	334	schedule_mfi.func_size = size;
	335
	336	get_frame_info(&schedule_mfi);
6057a798 FBH	337
	338	/*
	339	* Without schedule() frame info, result given by
	340	* thread_saved_pc() and get_wchan() are not reliable.
	341	*/
b5943182	342	if (schedule_mfi.pc_offset < 0)
6057a798	343	printk("Can't analyze schedule() prologue at %p\n", schedule);
63077519	344
1da177e4 LT	345	return 0;
	346	}
	347
	348	arch_initcall(frame_info_init);
	349
	350	/*
	351	* Return saved PC of a blocked thread.
	352	*/
	353	unsigned long thread_saved_pc(struct task_struct *tsk)
	354	{
	355	struct thread_struct *t = &tsk->thread;
	356
	357	/* New born processes are a special case */
	358	if (t->reg31 == (unsigned long) ret_from_fork)
	359	return t->reg31;
b5943182	360	if (schedule_mfi.pc_offset < 0)
1da177e4	361	return 0;
b5943182	362	return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
1da177e4 LT	363	}
1da177e4 LT	364
1da177e4	365
f66686f7	366	#ifdef CONFIG_KALLSYMS
4d157d5e FBH	367	/* used by show_backtrace() */
4d157d5e FBH	368	unsigned long unwind_stack(struct task_struct task, unsigned long sp,
1924600c	369	unsigned long pc, unsigned long *ra)
f66686f7 AN	370	{
	371	unsigned long stack_page;
	372	struct mips_frame_info info;
f66686f7	373	unsigned long size, ofs;
4d157d5e	374	int leaf;
1924600c AN	375	extern void ret_from_irq(void);
1924600c AN	376	extern void ret_from_exception(void);
f66686f7 AN	377
	378	stack_page = (unsigned long)task_stack_page(task);
	379	if (!stack_page)
	380	return 0;
	381
1924600c AN	382	/*
	383	* If we reached the bottom of interrupt context,
	384	* return saved pc in pt_regs.
	385	*/
	386	if (pc == (unsigned long)ret_from_irq \|\|
	387	pc == (unsigned long)ret_from_exception) {
	388	struct pt_regs *regs;
	389	if (*sp >= stack_page &&
	390	sp + sizeof(regs) <= stack_page + THREAD_SIZE - 32) {
	391	regs = (struct pt_regs )sp;
	392	pc = regs->cp0_epc;
	393	if (__kernel_text_address(pc)) {
	394	*sp = regs->regs[29];
	395	*ra = regs->regs[31];
	396	return pc;
	397	}
	398	}
	399	return 0;
	400	}
55b74283	401	if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
f66686f7	402	return 0;
1fd69098 FBH	403	/*
	404	* Return ra if an exception occured at the first instruction
	405	*/
1924600c AN	406	if (unlikely(ofs == 0)) {
	407	pc = *ra;
	408	*ra = 0;
	409	return pc;
	410	}
f66686f7 AN	411
	412	info.func = (void *)(pc - ofs);
	413	info.func_size = ofs; /* analyze from start to ofs */
4d157d5e FBH	414	leaf = get_frame_info(&info);
4d157d5e FBH	415	if (leaf < 0)
f66686f7	416	return 0;
4d157d5e FBH	417
	418	if (*sp < stack_page \|\|
	419	*sp + info.frame_size > stack_page + THREAD_SIZE - 32)
f66686f7 AN	420	return 0;
f66686f7 AN	421
4d157d5e FBH	422	if (leaf)
	423	/*
	424	* For some extreme cases, get_frame_info() can
	425	* consider wrongly a nested function as a leaf
	426	* one. In that cases avoid to return always the
	427	* same value.
	428	*/
1924600c	429	pc = pc != ra ? ra : 0;
4d157d5e FBH	430	else
	431	pc = ((unsigned long )(sp))[info.pc_offset];
	432
	433	*sp += info.frame_size;
1924600c	434	*ra = 0;
4d157d5e	435	return __kernel_text_address(pc) ? pc : 0;
f66686f7 AN	436	}
f66686f7 AN	437	#endif
b5943182 FBH	438
	439	/*
	440	* get_wchan - a maintenance nightmare^W^Wpain in the ass ...
	441	*/
	442	unsigned long get_wchan(struct task_struct *task)
	443	{
	444	unsigned long pc = 0;
	445	#ifdef CONFIG_KALLSYMS
	446	unsigned long sp;
1924600c	447	unsigned long ra = 0;
b5943182 FBH	448	#endif
	449
	450	if (!task \|\| task == current \|\| task->state == TASK_RUNNING)
	451	goto out;
	452	if (!task_stack_page(task))
	453	goto out;
	454
	455	pc = thread_saved_pc(task);
	456
	457	#ifdef CONFIG_KALLSYMS
	458	sp = task->thread.reg29 + schedule_mfi.frame_size;
	459
	460	while (in_sched_functions(pc))
1924600c	461	pc = unwind_stack(task, &sp, pc, &ra);
b5943182 FBH	462	#endif
	463
	464	out:
	465	return pc;
	466	}
94109102 FBH	467
	468	/*
	469	* Don't forget that the stack pointer must be aligned on a 8 bytes
	470	* boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
	471	*/
	472	unsigned long arch_align_stack(unsigned long sp)
	473	{
	474	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
	475	sp -= get_random_int() & ~PAGE_MASK;
	476
	477	return sp & ALMASK;
	478	}