[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
 * Copyright (C) 2013  Imagination Technologies Ltd.
 */
#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/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/msa.h>
#include <asm/pgtable.h>
#include <asm/mipsregs.h>
#include <asm/processor.h>
#include <asm/reg.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>
#include <asm/irq_regs.h>

#ifdef CONFIG_HOTPLUG_CPU
void arch_cpu_idle_dead(void)
{
	/* What the heck is this check doing ? */
	if (!cpu_isset(smp_processor_id(), cpu_callin_map))
		play_dead();
}
#endif

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);
	status |= KU_USER;
	regs->cp0_status = status;
	clear_used_math();
	clear_fpu_owner();
	init_dsp();
	clear_thread_flag(TIF_USEDMSA);
	clear_thread_flag(TIF_MSA_CTX_LIVE);
	disable_msa();
	regs->cp0_epc = pc;
	regs->regs[29] = sp;
}

void exit_thread(void)
{
}

void flush_thread(void)
{
}

int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
	/*
	 * Save any process state which is live in hardware registers to the
	 * parent context prior to duplication. This prevents the new child
	 * state becoming stale if the parent is preempted before copy_thread()
	 * gets a chance to save the parent's live hardware registers to the
	 * child context.
	 */
	preempt_disable();

	if (is_msa_enabled())
		save_msa(current);
	else if (is_fpu_owner())
		_save_fp(current);

	save_dsp(current);

	preempt_enable();

	*dst = *src;
	return 0;
}

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;

	/* 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);

	clear_tsk_thread_flag(p, TIF_USEDFPU);
	clear_tsk_thread_flag(p, TIF_USEDMSA);
	clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE);

#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;
}

#ifdef CONFIG_CC_STACKPROTECTOR
#include <linux/stackprotector.h>
unsigned long __stack_chk_guard __read_mostly;
EXPORT_SYMBOL(__stack_chk_guard);
#endif

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

#define J_TARGET(pc,target)	\
		(((unsigned long)(pc) & 0xf0000000) | ((target) << 2))

static inline int is_ra_save_ins(union mips_instruction *ip)
{
#ifdef CONFIG_CPU_MICROMIPS
	union mips_instruction mmi;

	/*
	 * swsp ra,offset
	 * swm16 reglist,offset(sp)
	 * swm32 reglist,offset(sp)
	 * sw32 ra,offset(sp)
	 * jradiussp - NOT SUPPORTED
	 *
	 * microMIPS is way more fun...
	 */
	if (mm_insn_16bit(ip->halfword[0])) {
		mmi.word = (ip->halfword[0] << 16);
		return (mmi.mm16_r5_format.opcode == mm_swsp16_op &&
			mmi.mm16_r5_format.rt == 31) ||
		       (mmi.mm16_m_format.opcode == mm_pool16c_op &&
			mmi.mm16_m_format.func == mm_swm16_op);
	}
	else {
		mmi.halfword[0] = ip->halfword[1];
		mmi.halfword[1] = ip->halfword[0];
		return (mmi.mm_m_format.opcode == mm_pool32b_op &&
			mmi.mm_m_format.rd > 9 &&
			mmi.mm_m_format.base == 29 &&
			mmi.mm_m_format.func == mm_swm32_func) ||
		       (mmi.i_format.opcode == mm_sw32_op &&
			mmi.i_format.rs == 29 &&
			mmi.i_format.rt == 31);
	}
#else
	/* 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;
#endif
}

static inline int is_jump_ins(union mips_instruction *ip)
{
#ifdef CONFIG_CPU_MICROMIPS
	/*
	 * jr16,jrc,jalr16,jalr16
	 * jal
	 * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
	 * jraddiusp - NOT SUPPORTED
	 *
	 * microMIPS is kind of more fun...
	 */
	union mips_instruction mmi;

	mmi.word = (ip->halfword[0] << 16);

	if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&
	    (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||
	    ip->j_format.opcode == mm_jal32_op)
		return 1;
	if (ip->r_format.opcode != mm_pool32a_op ||
			ip->r_format.func != mm_pool32axf_op)
		return 0;
	return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op;
#else
	if (ip->j_format.opcode == j_op)
		return 1;
	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;
#endif
}

static inline int is_sp_move_ins(union mips_instruction *ip)
{
#ifdef CONFIG_CPU_MICROMIPS
	/*
	 * addiusp -imm
	 * addius5 sp,-imm
	 * addiu32 sp,sp,-imm
	 * jradiussp - NOT SUPPORTED
	 *
	 * microMIPS is not more fun...
	 */
	if (mm_insn_16bit(ip->halfword[0])) {
		union mips_instruction mmi;

		mmi.word = (ip->halfword[0] << 16);
		return (mmi.mm16_r3_format.opcode == mm_pool16d_op &&
			mmi.mm16_r3_format.simmediate && mm_addiusp_func) ||
		       (mmi.mm16_r5_format.opcode == mm_pool16d_op &&
			mmi.mm16_r5_format.rt == 29);
	}
	return ip->mm_i_format.opcode == mm_addiu32_op &&
	       ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29;
#else
	/* 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;
#endif
	return 0;
}

static int get_frame_info(struct mips_frame_info *info)
{
#ifdef CONFIG_CPU_MICROMIPS
	union mips_instruction *ip = (void *) (((char *) info->func) - 1);
#else
	union mips_instruction *ip = info->func;
#endif
	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_jump_ins(ip))
			break;
		if (!info->frame_size) {
			if (is_sp_move_ins(ip))
			{
#ifdef CONFIG_CPU_MICROMIPS
				if (mm_insn_16bit(ip->halfword[0]))
				{
					unsigned short tmp;

					if (ip->halfword[0] & mm_addiusp_func)
					{
						tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
						info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));
					} else {
						tmp = (ip->halfword[0] >> 1);
						info->frame_size = -(signed short)(tmp & 0xf);
					}
					ip = (void *) &ip->halfword[1];
					ip--;
				} else
#endif
				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;

#ifdef CONFIG_KALLSYMS
static unsigned long get___schedule_addr(void)
{
	return kallsyms_lookup_name("__schedule");
}
#else
static unsigned long get___schedule_addr(void)
{
	union mips_instruction *ip = (void *)schedule;
	int max_insns = 8;
	int i;

	for (i = 0; i < max_insns; i++, ip++) {
		if (ip->j_format.opcode == j_op)
			return J_TARGET(ip, ip->j_format.target);
	}
	return 0;
}
#endif

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

	addr = get___schedule_addr();
	if (!addr)
		addr = (unsigned long)schedule;

#ifdef CONFIG_KALLSYMS
	kallsyms_lookup_size_offset(addr, &size, &ofs);
#endif
	schedule_mfi.func = (void *)addr;
	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;
}

static void arch_dump_stack(void *info)
{
	struct pt_regs *regs;

	regs = get_irq_regs();

	if (regs)
		show_regs(regs);

	dump_stack();
}

void arch_trigger_all_cpu_backtrace(bool include_self)
{
	smp_call_function(arch_dump_stack, NULL, 1);
}
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.
1da177e4 LT	9	* Copyright (C) 2004 Thiemo Seufer
34c2f668	10	* Copyright (C) 2013 Imagination Technologies Ltd.
1da177e4	11	*/
1da177e4	12	#include <linux/errno.h>
1da177e4	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>
cae39d13	19	#include <linux/export.h>
1da177e4	20	#include <linux/ptrace.h>
1da177e4 LT	21	#include <linux/mman.h>
	22	#include <linux/personality.h>
	23	#include <linux/sys.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	33	#include <asm/fpu.h>
1db1af84	34	#include <asm/msa.h>
1da177e4	35	#include <asm/pgtable.h>
1da177e4 LT	36	#include <asm/mipsregs.h>
1da177e4 LT	37	#include <asm/processor.h>
60be939c	38	#include <asm/reg.h>
1da177e4 LT	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>
1df0f0ff	44	#include <asm/stacktrace.h>
856839b7	45	#include <asm/irq_regs.h>
1da177e4	46
cdbedc61 TG	47	#ifdef CONFIG_HOTPLUG_CPU
cdbedc61 TG	48	void arch_cpu_idle_dead(void)
1da177e4	49	{
cdbedc61 TG	50	/* What the heck is this check doing ? */
	51	if (!cpu_isset(smp_processor_id(), cpu_callin_map))
	52	play_dead();
	53	}
	54	#endif
1b2bc75c	55
1da177e4	56	asmlinkage void ret_from_fork(void);
8f54bcac	57	asmlinkage void ret_from_kernel_thread(void);
1da177e4 LT	58
	59	void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
	60	{
	61	unsigned long status;
	62
	63	/* New thread loses kernel privileges. */
bbaf238b	64	status = regs->cp0_status & ~(ST0_CU0\|ST0_CU1\|ST0_FR\|KU_MASK);
1da177e4 LT	65	status \|= KU_USER;
	66	regs->cp0_status = status;
	67	clear_used_math();
e04582b7	68	clear_fpu_owner();
a3056b1c	69	init_dsp();
7daef8f2	70	clear_thread_flag(TIF_USEDMSA);
1db1af84 PB	71	clear_thread_flag(TIF_MSA_CTX_LIVE);
1db1af84 PB	72	disable_msa();
1da177e4 LT	73	regs->cp0_epc = pc;
1da177e4 LT	74	regs->regs[29] = sp;
1da177e4 LT	75	}
	76
	77	void exit_thread(void)
	78	{
	79	}
	80
	81	void flush_thread(void)
	82	{
	83	}
	84
39148e94 JH	85	int arch_dup_task_struct(struct task_struct dst, struct task_struct src)
	86	{
	87	/*
	88	* Save any process state which is live in hardware registers to the
	89	* parent context prior to duplication. This prevents the new child
	90	* state becoming stale if the parent is preempted before copy_thread()
	91	* gets a chance to save the parent's live hardware registers to the
	92	* child context.
	93	*/
	94	preempt_disable();
	95
	96	if (is_msa_enabled())
	97	save_msa(current);
	98	else if (is_fpu_owner())
	99	_save_fp(current);
	100
	101	save_dsp(current);
	102
	103	preempt_enable();
	104
	105	dst = src;
	106	return 0;
	107	}
	108
6f2c55b8	109	int copy_thread(unsigned long clone_flags, unsigned long usp,
afa86fc4	110	unsigned long arg, struct task_struct *p)
1da177e4	111	{
75bb07e7	112	struct thread_info *ti = task_thread_info(p);
afa86fc4	113	struct pt_regs childregs, regs = current_pt_regs();
484889fc	114	unsigned long childksp;
3c37026d	115	p->set_child_tid = p->clear_child_tid = NULL;
1da177e4	116
75bb07e7	117	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
1da177e4	118
1da177e4 LT	119	/* set up new TSS. */
1da177e4 LT	120	childregs = (struct pt_regs *) childksp - 1;
484889fc DD	121	/* Put the stack after the struct pt_regs. */
484889fc DD	122	childksp = (unsigned long) childregs;
8f54bcac AV	123	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2\|ST0_CU1);
	124	if (unlikely(p->flags & PF_KTHREAD)) {
	125	unsigned long status = p->thread.cp0_status;
	126	memset(childregs, 0, sizeof(struct pt_regs));
	127	ti->addr_limit = KERNEL_DS;
	128	p->thread.reg16 = usp; /* fn */
	129	p->thread.reg17 = arg;
	130	p->thread.reg29 = childksp;
	131	p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
	132	#if defined(CONFIG_CPU_R3000) \|\| defined(CONFIG_CPU_TX39XX)
	133	status = (status & ~(ST0_KUP \| ST0_IEP \| ST0_IEC)) \|
	134	((status & (ST0_KUC \| ST0_IEC)) << 2);
	135	#else
	136	status \|= ST0_EXL;
	137	#endif
	138	childregs->cp0_status = status;
	139	return 0;
	140	}
1da177e4	141	childregs = regs;
70342287 RB	142	childregs->regs[7] = 0; /* Clear error flag */
70342287 RB	143	childregs->regs[2] = 0; /* Child gets zero as return value */
64b3122d AV	144	if (usp)
64b3122d AV	145	childregs->regs[29] = usp;
8f54bcac	146	ti->addr_limit = USER_DS;
1da177e4	147
1da177e4 LT	148	p->thread.reg29 = (unsigned long) childregs;
	149	p->thread.reg31 = (unsigned long) ret_from_fork;
	150
	151	/*
	152	* New tasks lose permission to use the fpu. This accelerates context
	153	* switching for most programs since they don't use the fpu.
	154	*/
1da177e4	155	childregs->cp0_status &= ~(ST0_CU2\|ST0_CU1);
1da177e4	156
1da177e4	157	clear_tsk_thread_flag(p, TIF_USEDFPU);
7daef8f2 PB	158	clear_tsk_thread_flag(p, TIF_USEDMSA);
7daef8f2 PB	159	clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE);
1da177e4	160
f088fc84	161	#ifdef CONFIG_MIPS_MT_FPAFF
6657fe0a	162	clear_tsk_thread_flag(p, TIF_FPUBOUND);
f088fc84 RB	163	#endif /* CONFIG_MIPS_MT_FPAFF */
f088fc84 RB	164
3c37026d RB	165	if (clone_flags & CLONE_SETTLS)
	166	ti->tp_value = regs->regs[7];
	167
1da177e4 LT	168	return 0;
	169	}
	170
36ecafc5 GF	171	#ifdef CONFIG_CC_STACKPROTECTOR
	172	#include <linux/stackprotector.h>
	173	unsigned long __stack_chk_guard __read_mostly;
	174	EXPORT_SYMBOL(__stack_chk_guard);
	175	#endif
	176
b5943182 FBH	177	struct mips_frame_info {
	178	void *func;
	179	unsigned long func_size;
	180	int frame_size;
	181	int pc_offset;
	182	};
dc953df1	183
5000653e TW	184	#define J_TARGET(pc,target) \
	185	(((unsigned long)(pc) & 0xf0000000) \| ((target) << 2))
	186
c0efbb6d FBH	187	static inline int is_ra_save_ins(union mips_instruction *ip)
c0efbb6d FBH	188	{
34c2f668 LY	189	#ifdef CONFIG_CPU_MICROMIPS
	190	union mips_instruction mmi;
	191
	192	/*
	193	* swsp ra,offset
	194	* swm16 reglist,offset(sp)
	195	* swm32 reglist,offset(sp)
	196	* sw32 ra,offset(sp)
	197	* jradiussp - NOT SUPPORTED
	198	*
	199	* microMIPS is way more fun...
	200	*/
	201	if (mm_insn_16bit(ip->halfword[0])) {
	202	mmi.word = (ip->halfword[0] << 16);
635c9907 RB	203	return (mmi.mm16_r5_format.opcode == mm_swsp16_op &&
	204	mmi.mm16_r5_format.rt == 31) \|\|
	205	(mmi.mm16_m_format.opcode == mm_pool16c_op &&
	206	mmi.mm16_m_format.func == mm_swm16_op);
34c2f668 LY	207	}
	208	else {
	209	mmi.halfword[0] = ip->halfword[1];
	210	mmi.halfword[1] = ip->halfword[0];
635c9907 RB	211	return (mmi.mm_m_format.opcode == mm_pool32b_op &&
	212	mmi.mm_m_format.rd > 9 &&
	213	mmi.mm_m_format.base == 29 &&
	214	mmi.mm_m_format.func == mm_swm32_func) \|\|
	215	(mmi.i_format.opcode == mm_sw32_op &&
	216	mmi.i_format.rs == 29 &&
	217	mmi.i_format.rt == 31);
34c2f668 LY	218	}
34c2f668 LY	219	#else
c0efbb6d FBH	220	/* sw / sd $ra, offset($sp) */
	221	return (ip->i_format.opcode == sw_op \|\| ip->i_format.opcode == sd_op) &&
	222	ip->i_format.rs == 29 &&
	223	ip->i_format.rt == 31;
34c2f668	224	#endif
c0efbb6d FBH	225	}
c0efbb6d FBH	226
e7438c4b	227	static inline int is_jump_ins(union mips_instruction *ip)
c0efbb6d	228	{
34c2f668 LY	229	#ifdef CONFIG_CPU_MICROMIPS
	230	/*
	231	* jr16,jrc,jalr16,jalr16
	232	* jal
	233	* jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
	234	* jraddiusp - NOT SUPPORTED
	235	*
	236	* microMIPS is kind of more fun...
	237	*/
	238	union mips_instruction mmi;
	239
	240	mmi.word = (ip->halfword[0] << 16);
	241
	242	if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&
	243	(mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) \|\|
	244	ip->j_format.opcode == mm_jal32_op)
	245	return 1;
	246	if (ip->r_format.opcode != mm_pool32a_op \|\|
	247	ip->r_format.func != mm_pool32axf_op)
	248	return 0;
635c9907	249	return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op;
34c2f668	250	#else
e7438c4b TW	251	if (ip->j_format.opcode == j_op)
e7438c4b TW	252	return 1;
c0efbb6d FBH	253	if (ip->j_format.opcode == jal_op)
	254	return 1;
	255	if (ip->r_format.opcode != spec_op)
	256	return 0;
	257	return ip->r_format.func == jalr_op \|\| ip->r_format.func == jr_op;
34c2f668	258	#endif
c0efbb6d FBH	259	}
	260
	261	static inline int is_sp_move_ins(union mips_instruction *ip)
	262	{
34c2f668 LY	263	#ifdef CONFIG_CPU_MICROMIPS
	264	/*
	265	* addiusp -imm
	266	* addius5 sp,-imm
	267	* addiu32 sp,sp,-imm
	268	* jradiussp - NOT SUPPORTED
	269	*
	270	* microMIPS is not more fun...
	271	*/
	272	if (mm_insn_16bit(ip->halfword[0])) {
	273	union mips_instruction mmi;
	274
	275	mmi.word = (ip->halfword[0] << 16);
635c9907 RB	276	return (mmi.mm16_r3_format.opcode == mm_pool16d_op &&
	277	mmi.mm16_r3_format.simmediate && mm_addiusp_func) \|\|
	278	(mmi.mm16_r5_format.opcode == mm_pool16d_op &&
	279	mmi.mm16_r5_format.rt == 29);
34c2f668	280	}
635c9907 RB	281	return ip->mm_i_format.opcode == mm_addiu32_op &&
635c9907 RB	282	ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29;
34c2f668	283	#else
c0efbb6d FBH	284	/* addiu/daddiu sp,sp,-imm */
	285	if (ip->i_format.rs != 29 \|\| ip->i_format.rt != 29)
	286	return 0;
	287	if (ip->i_format.opcode == addiu_op \|\| ip->i_format.opcode == daddiu_op)
	288	return 1;
34c2f668	289	#endif
c0efbb6d FBH	290	return 0;
	291	}
	292
f66686f7	293	static int get_frame_info(struct mips_frame_info *info)
1da177e4	294	{
34c2f668 LY	295	#ifdef CONFIG_CPU_MICROMIPS
	296	union mips_instruction ip = (void ) (((char *) info->func) - 1);
	297	#else
c0efbb6d	298	union mips_instruction *ip = info->func;
34c2f668	299	#endif
29b376ff FBH	300	unsigned max_insns = info->func_size / sizeof(union mips_instruction);
29b376ff FBH	301	unsigned i;
c0efbb6d	302
1da177e4	303	info->pc_offset = -1;
63077519	304	info->frame_size = 0;
1da177e4	305
29b376ff FBH	306	if (!ip)
	307	goto err;
	308
	309	if (max_insns == 0)
	310	max_insns = 128U; /* unknown function size */
	311	max_insns = min(128U, max_insns);
	312
c0efbb6d FBH	313	for (i = 0; i < max_insns; i++, ip++) {
c0efbb6d FBH	314
e7438c4b	315	if (is_jump_ins(ip))
63077519	316	break;
0cceb4aa FBH	317	if (!info->frame_size) {
0cceb4aa FBH	318	if (is_sp_move_ins(ip))
34c2f668 LY	319	{
	320	#ifdef CONFIG_CPU_MICROMIPS
	321	if (mm_insn_16bit(ip->halfword[0]))
	322	{
	323	unsigned short tmp;
	324
	325	if (ip->halfword[0] & mm_addiusp_func)
	326	{
	327	tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
	328	info->frame_size = -(signed short)(tmp \| ((tmp & 0x100) ? 0xfe00 : 0));
	329	} else {
	330	tmp = (ip->halfword[0] >> 1);
	331	info->frame_size = -(signed short)(tmp & 0xf);
	332	}
	333	ip = (void *) &ip->halfword[1];
	334	ip--;
	335	} else
	336	#endif
0cceb4aa	337	info->frame_size = - ip->i_format.simmediate;
34c2f668	338	}
0cceb4aa	339	continue;
63077519	340	}
0cceb4aa	341	if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
63077519 AN	342	info->pc_offset =
63077519 AN	343	ip->i_format.simmediate / sizeof(long);
0cceb4aa	344	break;
1da177e4 LT	345	}
1da177e4 LT	346	}
f66686f7 AN	347	if (info->frame_size && info->pc_offset >= 0) /* nested */
	348	return 0;
	349	if (info->pc_offset < 0) /* leaf */
	350	return 1;
	351	/* prologue seems boggus... */
29b376ff	352	err:
f66686f7	353	return -1;
1da177e4 LT	354	}
1da177e4 LT	355
b5943182 FBH	356	static struct mips_frame_info schedule_mfi __read_mostly;
b5943182 FBH	357
5000653e TW	358	#ifdef CONFIG_KALLSYMS
	359	static unsigned long get___schedule_addr(void)
	360	{
	361	return kallsyms_lookup_name("__schedule");
	362	}
	363	#else
	364	static unsigned long get___schedule_addr(void)
	365	{
	366	union mips_instruction ip = (void )schedule;
	367	int max_insns = 8;
	368	int i;
	369
	370	for (i = 0; i < max_insns; i++, ip++) {
	371	if (ip->j_format.opcode == j_op)
	372	return J_TARGET(ip, ip->j_format.target);
	373	}
	374	return 0;
	375	}
	376	#endif
	377
1da177e4 LT	378	static int __init frame_info_init(void)
1da177e4 LT	379	{
b5943182	380	unsigned long size = 0;
63077519	381	#ifdef CONFIG_KALLSYMS
b5943182	382	unsigned long ofs;
5000653e TW	383	#endif
5000653e TW	384	unsigned long addr;
b5943182	385
5000653e TW	386	addr = get___schedule_addr();
	387	if (!addr)
	388	addr = (unsigned long)schedule;
	389
	390	#ifdef CONFIG_KALLSYMS
	391	kallsyms_lookup_size_offset(addr, &size, &ofs);
63077519	392	#endif
5000653e	393	schedule_mfi.func = (void *)addr;
b5943182 FBH	394	schedule_mfi.func_size = size;
	395
	396	get_frame_info(&schedule_mfi);
6057a798 FBH	397
	398	/*
	399	* Without schedule() frame info, result given by
	400	* thread_saved_pc() and get_wchan() are not reliable.
	401	*/
b5943182	402	if (schedule_mfi.pc_offset < 0)
6057a798	403	printk("Can't analyze schedule() prologue at %p\n", schedule);
63077519	404
1da177e4 LT	405	return 0;
	406	}
	407
	408	arch_initcall(frame_info_init);
	409
	410	/*
	411	* Return saved PC of a blocked thread.
	412	*/
	413	unsigned long thread_saved_pc(struct task_struct *tsk)
	414	{
	415	struct thread_struct *t = &tsk->thread;
	416
	417	/* New born processes are a special case */
	418	if (t->reg31 == (unsigned long) ret_from_fork)
	419	return t->reg31;
b5943182	420	if (schedule_mfi.pc_offset < 0)
1da177e4	421	return 0;
b5943182	422	return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
1da177e4 LT	423	}
1da177e4 LT	424
1da177e4	425
f66686f7	426	#ifdef CONFIG_KALLSYMS
94ea09c6 DK	427	/* generic stack unwinding function */
	428	unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
	429	unsigned long *sp,
	430	unsigned long pc,
	431	unsigned long *ra)
f66686f7	432	{
f66686f7	433	struct mips_frame_info info;
f66686f7	434	unsigned long size, ofs;
4d157d5e	435	int leaf;
1924600c AN	436	extern void ret_from_irq(void);
1924600c AN	437	extern void ret_from_exception(void);
f66686f7	438
f66686f7 AN	439	if (!stack_page)
	440	return 0;
	441
1924600c AN	442	/*
	443	* If we reached the bottom of interrupt context,
	444	* return saved pc in pt_regs.
	445	*/
	446	if (pc == (unsigned long)ret_from_irq \|\|
	447	pc == (unsigned long)ret_from_exception) {
	448	struct pt_regs *regs;
	449	if (*sp >= stack_page &&
	450	sp + sizeof(regs) <= stack_page + THREAD_SIZE - 32) {
	451	regs = (struct pt_regs )sp;
	452	pc = regs->cp0_epc;
	453	if (__kernel_text_address(pc)) {
	454	*sp = regs->regs[29];
	455	*ra = regs->regs[31];
	456	return pc;
	457	}
	458	}
	459	return 0;
	460	}
55b74283	461	if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
f66686f7	462	return 0;
1fd69098	463	/*
25985edc	464	* Return ra if an exception occurred at the first instruction
1fd69098	465	*/
1924600c AN	466	if (unlikely(ofs == 0)) {
	467	pc = *ra;
	468	*ra = 0;
	469	return pc;
	470	}
f66686f7 AN	471
	472	info.func = (void *)(pc - ofs);
	473	info.func_size = ofs; /* analyze from start to ofs */
4d157d5e FBH	474	leaf = get_frame_info(&info);
4d157d5e FBH	475	if (leaf < 0)
f66686f7	476	return 0;
4d157d5e FBH	477
	478	if (*sp < stack_page \|\|
	479	*sp + info.frame_size > stack_page + THREAD_SIZE - 32)
f66686f7 AN	480	return 0;
f66686f7 AN	481
4d157d5e FBH	482	if (leaf)
	483	/*
	484	* For some extreme cases, get_frame_info() can
	485	* consider wrongly a nested function as a leaf
	486	* one. In that cases avoid to return always the
	487	* same value.
	488	*/
1924600c	489	pc = pc != ra ? ra : 0;
4d157d5e FBH	490	else
	491	pc = ((unsigned long )(sp))[info.pc_offset];
	492
	493	*sp += info.frame_size;
1924600c	494	*ra = 0;
4d157d5e	495	return __kernel_text_address(pc) ? pc : 0;
f66686f7	496	}
94ea09c6 DK	497	EXPORT_SYMBOL(unwind_stack_by_address);
	498
	499	/* used by show_backtrace() */
	500	unsigned long unwind_stack(struct task_struct task, unsigned long sp,
	501	unsigned long pc, unsigned long *ra)
	502	{
	503	unsigned long stack_page = (unsigned long)task_stack_page(task);
	504	return unwind_stack_by_address(stack_page, sp, pc, ra);
	505	}
f66686f7	506	#endif
b5943182 FBH	507
	508	/*
	509	* get_wchan - a maintenance nightmare^W^Wpain in the ass ...
	510	*/
	511	unsigned long get_wchan(struct task_struct *task)
	512	{
	513	unsigned long pc = 0;
	514	#ifdef CONFIG_KALLSYMS
	515	unsigned long sp;
1924600c	516	unsigned long ra = 0;
b5943182 FBH	517	#endif
	518
	519	if (!task \|\| task == current \|\| task->state == TASK_RUNNING)
	520	goto out;
	521	if (!task_stack_page(task))
	522	goto out;
	523
	524	pc = thread_saved_pc(task);
	525
	526	#ifdef CONFIG_KALLSYMS
	527	sp = task->thread.reg29 + schedule_mfi.frame_size;
	528
	529	while (in_sched_functions(pc))
1924600c	530	pc = unwind_stack(task, &sp, pc, &ra);
b5943182 FBH	531	#endif
	532
	533	out:
	534	return pc;
	535	}
94109102 FBH	536
	537	/*
	538	* Don't forget that the stack pointer must be aligned on a 8 bytes
	539	* boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
	540	*/
	541	unsigned long arch_align_stack(unsigned long sp)
	542	{
	543	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
	544	sp -= get_random_int() & ~PAGE_MASK;
	545
	546	return sp & ALMASK;
	547	}
856839b7 ES	548
	549	static void arch_dump_stack(void *info)
	550	{
	551	struct pt_regs *regs;
	552
	553	regs = get_irq_regs();
	554
	555	if (regs)
	556	show_regs(regs);
	557
	558	dump_stack();
	559	}
	560
	561	void arch_trigger_all_cpu_backtrace(bool include_self)
	562	{
	563	smp_call_function(arch_dump_stack, NULL, 1);
	564	}