[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/sched.h>
#include <linux/tick.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/export.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/personality.h>
#include <linux/sys.h>
#include <linux/user.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/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)
{
	int cpu;

	/* CPU is going idle. */
	cpu = smp_processor_id();

	/* endless idle loop with no priority at all */
	while (1) {
		tick_nohz_idle_enter();
		rcu_idle_enter();
		while (!need_resched() && cpu_online(cpu)) {
#ifdef CONFIG_MIPS_MT_SMTC
			extern void smtc_idle_loop_hook(void);

			smtc_idle_loop_hook();
#endif

			if (cpu_wait) {
				/* Don't trace irqs off for idle */
				stop_critical_timings();
				(*cpu_wait)();
				start_critical_timings();
			}
		}
#ifdef CONFIG_HOTPLUG_CPU
		if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map))
			play_dead();
#endif
		rcu_idle_exit();
		tick_nohz_idle_exit();
		schedule_preempt_disabled();
	}
}

asmlinkage void ret_from_fork(void);
asmlinkage void ret_from_kernel_thread(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;
}

void exit_thread(void)
{
}

void flush_thread(void)
{
}

int copy_thread(unsigned long clone_flags, unsigned long usp,
	unsigned long arg, struct task_struct *p)
{
	struct thread_info *ti = task_thread_info(p);
	struct pt_regs *childregs, *regs = current_pt_regs();
	unsigned 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;
	/*  Put the stack after the struct pt_regs.  */
	childksp = (unsigned long) childregs;
	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
	if (unlikely(p->flags & PF_KTHREAD)) {
		unsigned long status = p->thread.cp0_status;
		memset(childregs, 0, sizeof(struct pt_regs));
		ti->addr_limit = KERNEL_DS;
		p->thread.reg16 = usp; /* fn */
		p->thread.reg17 = arg;
		p->thread.reg29 = childksp;
		p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
		status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
			 ((status & (ST0_KUC | ST0_IEC)) << 2);
#else
		status |= ST0_EXL;
#endif
		childregs->cp0_status = status;
		return 0;
	}
	*childregs = *regs;
	childregs->regs[7] = 0; /* Clear error flag */
	childregs->regs[2] = 0; /* Child gets zero as return value */
	if (usp)
		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.
	 */
	childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);

#ifdef CONFIG_MIPS_MT_SMTC
	/*
	 * SMTC restores TCStatus after Status, and the CU bits
	 * are aliased there.
	 */
	childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1);
#endif
	clear_tsk_thread_flag(p, TIF_USEDFPU);

#ifdef CONFIG_MIPS_MT_FPAFF
	clear_tsk_thread_flag(p, TIF_FPUBOUND);
#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;
}

/*
 *
 */
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
/* generic stack unwinding function */
unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
					      unsigned long *sp,
					      unsigned long pc,
					      unsigned long *ra)
{
	struct mips_frame_info info;
	unsigned long size, ofs;
	int leaf;
	extern void ret_from_irq(void);
	extern void ret_from_exception(void);

	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 occurred 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;
}
EXPORT_SYMBOL(unwind_stack_by_address);

/* 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 = (unsigned long)task_stack_page(task);
	return unwind_stack_by_address(stack_page, sp, pc, ra);
}
#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	11	#include <linux/errno.h>
1da177e4	12	#include <linux/sched.h>
7bcf7717	13	#include <linux/tick.h>
1da177e4 LT	14	#include <linux/kernel.h>
	15	#include <linux/mm.h>
	16	#include <linux/stddef.h>
	17	#include <linux/unistd.h>
cae39d13	18	#include <linux/export.h>
1da177e4	19	#include <linux/ptrace.h>
1da177e4 LT	20	#include <linux/mman.h>
	21	#include <linux/personality.h>
	22	#include <linux/sys.h>
	23	#include <linux/user.h>
1da177e4 LT	24	#include <linux/init.h>
1da177e4 LT	25	#include <linux/completion.h>
63077519	26	#include <linux/kallsyms.h>
94109102	27	#include <linux/random.h>
1da177e4	28
94109102	29	#include <asm/asm.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>
1da177e4 LT	34	#include <asm/pgtable.h>
1da177e4 LT	35	#include <asm/mipsregs.h>
	36	#include <asm/processor.h>
	37	#include <asm/uaccess.h>
	38	#include <asm/io.h>
	39	#include <asm/elf.h>
	40	#include <asm/isadep.h>
	41	#include <asm/inst.h>
1df0f0ff	42	#include <asm/stacktrace.h>
1da177e4	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	*/
b3f6df9f	49	void __noreturn cpu_idle(void)
1da177e4	50	{
1b2bc75c RB	51	int cpu;
	52
	53	/* CPU is going idle. */
	54	cpu = smp_processor_id();
	55
1da177e4 LT	56	/* endless idle loop with no priority at all */
1da177e4 LT	57	while (1) {
1268fbc7 FW	58	tick_nohz_idle_enter();
1268fbc7 FW	59	rcu_idle_enter();
1b2bc75c	60	while (!need_resched() && cpu_online(cpu)) {
9cc12363	61	#ifdef CONFIG_MIPS_MT_SMTC
447deafb RB	62	extern void smtc_idle_loop_hook(void);
447deafb RB	63
41c594ab	64	smtc_idle_loop_hook();
c68644d3	65	#endif
7a7ac952 WZ	66
	67	if (cpu_wait) {
	68	/* Don't trace irqs off for idle */
	69	stop_critical_timings();
1da177e4	70	(*cpu_wait)();
7a7ac952 WZ	71	start_critical_timings();
7a7ac952 WZ	72	}
41c594ab	73	}
1b2bc75c	74	#ifdef CONFIG_HOTPLUG_CPU
8add1ecb	75	if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map))
1b2bc75c RB	76	play_dead();
1b2bc75c RB	77	#endif
1268fbc7 FW	78	rcu_idle_exit();
1268fbc7 FW	79	tick_nohz_idle_exit();
bd2f5536	80	schedule_preempt_disabled();
1da177e4 LT	81	}
	82	}
	83
	84	asmlinkage void ret_from_fork(void);
8f54bcac	85	asmlinkage void ret_from_kernel_thread(void);
1da177e4 LT	86
	87	void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
	88	{
	89	unsigned long status;
	90
	91	/* New thread loses kernel privileges. */
bbaf238b	92	status = regs->cp0_status & ~(ST0_CU0\|ST0_CU1\|ST0_FR\|KU_MASK);
875d43e7	93	#ifdef CONFIG_64BIT
293c5bd1	94	status \|= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR;
1da177e4 LT	95	#endif
	96	status \|= KU_USER;
	97	regs->cp0_status = status;
	98	clear_used_math();
e04582b7	99	clear_fpu_owner();
e50c0a8f RB	100	if (cpu_has_dsp)
e50c0a8f RB	101	__init_dsp();
1da177e4 LT	102	regs->cp0_epc = pc;
1da177e4 LT	103	regs->regs[29] = sp;
1da177e4 LT	104	}
	105
	106	void exit_thread(void)
	107	{
	108	}
	109
	110	void flush_thread(void)
	111	{
	112	}
	113
6f2c55b8	114	int copy_thread(unsigned long clone_flags, unsigned long usp,
afa86fc4	115	unsigned long arg, struct task_struct *p)
1da177e4	116	{
75bb07e7	117	struct thread_info *ti = task_thread_info(p);
afa86fc4	118	struct pt_regs childregs, regs = current_pt_regs();
484889fc	119	unsigned long childksp;
3c37026d	120	p->set_child_tid = p->clear_child_tid = NULL;
1da177e4	121
75bb07e7	122	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
1da177e4 LT	123
	124	preempt_disable();
	125
e50c0a8f	126	if (is_fpu_owner())
1da177e4	127	save_fp(p);
e50c0a8f RB	128
	129	if (cpu_has_dsp)
	130	save_dsp(p);
1da177e4 LT	131
	132	preempt_enable();
	133
	134	/* set up new TSS. */
	135	childregs = (struct pt_regs *) childksp - 1;
484889fc DD	136	/* Put the stack after the struct pt_regs. */
484889fc DD	137	childksp = (unsigned long) childregs;
8f54bcac AV	138	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2\|ST0_CU1);
	139	if (unlikely(p->flags & PF_KTHREAD)) {
	140	unsigned long status = p->thread.cp0_status;
	141	memset(childregs, 0, sizeof(struct pt_regs));
	142	ti->addr_limit = KERNEL_DS;
	143	p->thread.reg16 = usp; /* fn */
	144	p->thread.reg17 = arg;
	145	p->thread.reg29 = childksp;
	146	p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
	147	#if defined(CONFIG_CPU_R3000) \|\| defined(CONFIG_CPU_TX39XX)
	148	status = (status & ~(ST0_KUP \| ST0_IEP \| ST0_IEC)) \|
	149	((status & (ST0_KUC \| ST0_IEC)) << 2);
	150	#else
	151	status \|= ST0_EXL;
	152	#endif
	153	childregs->cp0_status = status;
	154	return 0;
	155	}
1da177e4	156	childregs = regs;
70342287 RB	157	childregs->regs[7] = 0; /* Clear error flag */
70342287 RB	158	childregs->regs[2] = 0; /* Child gets zero as return value */
64b3122d AV	159	if (usp)
64b3122d AV	160	childregs->regs[29] = usp;
8f54bcac	161	ti->addr_limit = USER_DS;
1da177e4	162
1da177e4 LT	163	p->thread.reg29 = (unsigned long) childregs;
	164	p->thread.reg31 = (unsigned long) ret_from_fork;
	165
	166	/*
	167	* New tasks lose permission to use the fpu. This accelerates context
	168	* switching for most programs since they don't use the fpu.
	169	*/
1da177e4	170	childregs->cp0_status &= ~(ST0_CU2\|ST0_CU1);
1da177e4	171
9cc12363	172	#ifdef CONFIG_MIPS_MT_SMTC
f088fc84	173	/*
9cc12363 KK	174	* SMTC restores TCStatus after Status, and the CU bits
9cc12363 KK	175	* are aliased there.
f088fc84	176	*/
9cc12363 KK	177	childregs->cp0_tcstatus &= ~(ST0_CU2\|ST0_CU1);
9cc12363 KK	178	#endif
1da177e4 LT	179	clear_tsk_thread_flag(p, TIF_USEDFPU);
1da177e4 LT	180
f088fc84	181	#ifdef CONFIG_MIPS_MT_FPAFF
6657fe0a	182	clear_tsk_thread_flag(p, TIF_FPUBOUND);
f088fc84 RB	183	#endif /* CONFIG_MIPS_MT_FPAFF */
f088fc84 RB	184
3c37026d RB	185	if (clone_flags & CLONE_SETTLS)
	186	ti->tp_value = regs->regs[7];
	187
1da177e4 LT	188	return 0;
	189	}
	190
	191	/* Fill in the fpu structure for a core dump.. */
	192	int dump_fpu(struct pt_regs regs, elf_fpregset_t r)
	193	{
	194	memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));
	195
	196	return 1;
	197	}
	198
d56efda4	199	void elf_dump_regs(elf_greg_t gp, struct pt_regs regs)
1da177e4 LT	200	{
	201	int i;
	202
	203	for (i = 0; i < EF_R0; i++)
	204	gp[i] = 0;
	205	gp[EF_R0] = 0;
	206	for (i = 1; i <= 31; i++)
	207	gp[EF_R0 + i] = regs->regs[i];
	208	gp[EF_R26] = 0;
	209	gp[EF_R27] = 0;
	210	gp[EF_LO] = regs->lo;
	211	gp[EF_HI] = regs->hi;
	212	gp[EF_CP0_EPC] = regs->cp0_epc;
	213	gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
	214	gp[EF_CP0_STATUS] = regs->cp0_status;
	215	gp[EF_CP0_CAUSE] = regs->cp0_cause;
	216	#ifdef EF_UNUSED0
	217	gp[EF_UNUSED0] = 0;
	218	#endif
	219	}
	220
49a89efb	221	int dump_task_regs(struct task_struct tsk, elf_gregset_t regs)
71e0e556	222	{
40bc9c67	223	elf_dump_regs(*regs, task_pt_regs(tsk));
71e0e556 RB	224	return 1;
	225	}
	226
49a89efb	227	int dump_task_fpu(struct task_struct t, elf_fpregset_t fpr)
1da177e4 LT	228	{
	229	memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
	230
	231	return 1;
	232	}
	233
b5943182 FBH	234	/*
	235	*
	236	*/
	237	struct mips_frame_info {
	238	void *func;
	239	unsigned long func_size;
	240	int frame_size;
	241	int pc_offset;
	242	};
dc953df1	243
c0efbb6d FBH	244	static inline int is_ra_save_ins(union mips_instruction *ip)
	245	{
	246	/* sw / sd $ra, offset($sp) */
	247	return (ip->i_format.opcode == sw_op \|\| ip->i_format.opcode == sd_op) &&
	248	ip->i_format.rs == 29 &&
	249	ip->i_format.rt == 31;
	250	}
	251
	252	static inline int is_jal_jalr_jr_ins(union mips_instruction *ip)
	253	{
	254	if (ip->j_format.opcode == jal_op)
	255	return 1;
	256	if (ip->r_format.opcode != spec_op)
	257	return 0;
	258	return ip->r_format.func == jalr_op \|\| ip->r_format.func == jr_op;
	259	}
	260
	261	static inline int is_sp_move_ins(union mips_instruction *ip)
	262	{
	263	/* addiu/daddiu sp,sp,-imm */
	264	if (ip->i_format.rs != 29 \|\| ip->i_format.rt != 29)
	265	return 0;
	266	if (ip->i_format.opcode == addiu_op \|\| ip->i_format.opcode == daddiu_op)
	267	return 1;
	268	return 0;
	269	}
	270
f66686f7	271	static int get_frame_info(struct mips_frame_info *info)
1da177e4	272	{
c0efbb6d	273	union mips_instruction *ip = info->func;
29b376ff FBH	274	unsigned max_insns = info->func_size / sizeof(union mips_instruction);
29b376ff FBH	275	unsigned i;
c0efbb6d	276
1da177e4	277	info->pc_offset = -1;
63077519	278	info->frame_size = 0;
1da177e4	279
29b376ff FBH	280	if (!ip)
	281	goto err;
	282
	283	if (max_insns == 0)
	284	max_insns = 128U; /* unknown function size */
	285	max_insns = min(128U, max_insns);
	286
c0efbb6d FBH	287	for (i = 0; i < max_insns; i++, ip++) {
	288
	289	if (is_jal_jalr_jr_ins(ip))
63077519	290	break;
0cceb4aa FBH	291	if (!info->frame_size) {
	292	if (is_sp_move_ins(ip))
	293	info->frame_size = - ip->i_format.simmediate;
	294	continue;
63077519	295	}
0cceb4aa	296	if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
63077519 AN	297	info->pc_offset =
63077519 AN	298	ip->i_format.simmediate / sizeof(long);
0cceb4aa	299	break;
1da177e4 LT	300	}
1da177e4 LT	301	}
f66686f7 AN	302	if (info->frame_size && info->pc_offset >= 0) /* nested */
	303	return 0;
	304	if (info->pc_offset < 0) /* leaf */
	305	return 1;
	306	/* prologue seems boggus... */
29b376ff	307	err:
f66686f7	308	return -1;
1da177e4 LT	309	}
1da177e4 LT	310
b5943182 FBH	311	static struct mips_frame_info schedule_mfi __read_mostly;
b5943182 FBH	312
1da177e4 LT	313	static int __init frame_info_init(void)
1da177e4 LT	314	{
b5943182	315	unsigned long size = 0;
63077519	316	#ifdef CONFIG_KALLSYMS
b5943182	317	unsigned long ofs;
b5943182	318
55b74283	319	kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs);
63077519	320	#endif
b5943182 FBH	321	schedule_mfi.func = schedule;
	322	schedule_mfi.func_size = size;
	323
	324	get_frame_info(&schedule_mfi);
6057a798 FBH	325
	326	/*
	327	* Without schedule() frame info, result given by
	328	* thread_saved_pc() and get_wchan() are not reliable.
	329	*/
b5943182	330	if (schedule_mfi.pc_offset < 0)
6057a798	331	printk("Can't analyze schedule() prologue at %p\n", schedule);
63077519	332
1da177e4 LT	333	return 0;
	334	}
	335
	336	arch_initcall(frame_info_init);
	337
	338	/*
	339	* Return saved PC of a blocked thread.
	340	*/
	341	unsigned long thread_saved_pc(struct task_struct *tsk)
	342	{
	343	struct thread_struct *t = &tsk->thread;
	344
	345	/* New born processes are a special case */
	346	if (t->reg31 == (unsigned long) ret_from_fork)
	347	return t->reg31;
b5943182	348	if (schedule_mfi.pc_offset < 0)
1da177e4	349	return 0;
b5943182	350	return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
1da177e4 LT	351	}
1da177e4 LT	352
1da177e4	353
f66686f7	354	#ifdef CONFIG_KALLSYMS
94ea09c6 DK	355	/* generic stack unwinding function */
	356	unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
	357	unsigned long *sp,
	358	unsigned long pc,
	359	unsigned long *ra)
f66686f7	360	{
f66686f7	361	struct mips_frame_info info;
f66686f7	362	unsigned long size, ofs;
4d157d5e	363	int leaf;
1924600c AN	364	extern void ret_from_irq(void);
1924600c AN	365	extern void ret_from_exception(void);
f66686f7	366
f66686f7 AN	367	if (!stack_page)
	368	return 0;
	369
1924600c AN	370	/*
	371	* If we reached the bottom of interrupt context,
	372	* return saved pc in pt_regs.
	373	*/
	374	if (pc == (unsigned long)ret_from_irq \|\|
	375	pc == (unsigned long)ret_from_exception) {
	376	struct pt_regs *regs;
	377	if (*sp >= stack_page &&
	378	sp + sizeof(regs) <= stack_page + THREAD_SIZE - 32) {
	379	regs = (struct pt_regs )sp;
	380	pc = regs->cp0_epc;
	381	if (__kernel_text_address(pc)) {
	382	*sp = regs->regs[29];
	383	*ra = regs->regs[31];
	384	return pc;
	385	}
	386	}
	387	return 0;
	388	}
55b74283	389	if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
f66686f7	390	return 0;
1fd69098	391	/*
25985edc	392	* Return ra if an exception occurred at the first instruction
1fd69098	393	*/
1924600c AN	394	if (unlikely(ofs == 0)) {
	395	pc = *ra;
	396	*ra = 0;
	397	return pc;
	398	}
f66686f7 AN	399
	400	info.func = (void *)(pc - ofs);
	401	info.func_size = ofs; /* analyze from start to ofs */
4d157d5e FBH	402	leaf = get_frame_info(&info);
4d157d5e FBH	403	if (leaf < 0)
f66686f7	404	return 0;
4d157d5e FBH	405
	406	if (*sp < stack_page \|\|
	407	*sp + info.frame_size > stack_page + THREAD_SIZE - 32)
f66686f7 AN	408	return 0;
f66686f7 AN	409
4d157d5e FBH	410	if (leaf)
	411	/*
	412	* For some extreme cases, get_frame_info() can
	413	* consider wrongly a nested function as a leaf
	414	* one. In that cases avoid to return always the
	415	* same value.
	416	*/
1924600c	417	pc = pc != ra ? ra : 0;
4d157d5e FBH	418	else
	419	pc = ((unsigned long )(sp))[info.pc_offset];
	420
	421	*sp += info.frame_size;
1924600c	422	*ra = 0;
4d157d5e	423	return __kernel_text_address(pc) ? pc : 0;
f66686f7	424	}
94ea09c6 DK	425	EXPORT_SYMBOL(unwind_stack_by_address);
	426
	427	/* used by show_backtrace() */
	428	unsigned long unwind_stack(struct task_struct task, unsigned long sp,
	429	unsigned long pc, unsigned long *ra)
	430	{
	431	unsigned long stack_page = (unsigned long)task_stack_page(task);
	432	return unwind_stack_by_address(stack_page, sp, pc, ra);
	433	}
f66686f7	434	#endif
b5943182 FBH	435
	436	/*
	437	* get_wchan - a maintenance nightmare^W^Wpain in the ass ...
	438	*/
	439	unsigned long get_wchan(struct task_struct *task)
	440	{
	441	unsigned long pc = 0;
	442	#ifdef CONFIG_KALLSYMS
	443	unsigned long sp;
1924600c	444	unsigned long ra = 0;
b5943182 FBH	445	#endif
	446
	447	if (!task \|\| task == current \|\| task->state == TASK_RUNNING)
	448	goto out;
	449	if (!task_stack_page(task))
	450	goto out;
	451
	452	pc = thread_saved_pc(task);
	453
	454	#ifdef CONFIG_KALLSYMS
	455	sp = task->thread.reg29 + schedule_mfi.frame_size;
	456
	457	while (in_sched_functions(pc))
1924600c	458	pc = unwind_stack(task, &sp, pc, &ra);
b5943182 FBH	459	#endif
	460
	461	out:
	462	return pc;
	463	}
94109102 FBH	464
	465	/*
	466	* Don't forget that the stack pointer must be aligned on a 8 bytes
	467	* boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
	468	*/
	469	unsigned long arch_align_stack(unsigned long sp)
	470	{
	471	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
	472	sp -= get_random_int() & ~PAGE_MASK;
	473
	474	return sp & ALMASK;
	475	}