[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 ([email protected])
 * 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/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>

#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);
#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;
};

#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;
}
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 ([email protected])
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>
	24	#include <linux/user.h>
1da177e4 LT	25	#include <linux/init.h>
1da177e4 LT	26	#include <linux/completion.h>
63077519	27	#include <linux/kallsyms.h>
94109102	28	#include <linux/random.h>
1da177e4	29
94109102	30	#include <asm/asm.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>
1da177e4 LT	35	#include <asm/pgtable.h>
1da177e4 LT	36	#include <asm/mipsregs.h>
	37	#include <asm/processor.h>
	38	#include <asm/uaccess.h>
	39	#include <asm/io.h>
	40	#include <asm/elf.h>
	41	#include <asm/isadep.h>
	42	#include <asm/inst.h>
1df0f0ff	43	#include <asm/stacktrace.h>
1da177e4	44
cdbedc61 TG	45	#ifdef CONFIG_HOTPLUG_CPU
cdbedc61 TG	46	void arch_cpu_idle_dead(void)
1da177e4	47	{
cdbedc61 TG	48	/* What the heck is this check doing ? */
	49	if (!cpu_isset(smp_processor_id(), cpu_callin_map))
	50	play_dead();
	51	}
	52	#endif
1b2bc75c	53
1da177e4	54	asmlinkage void ret_from_fork(void);
8f54bcac	55	asmlinkage void ret_from_kernel_thread(void);
1da177e4 LT	56
	57	void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
	58	{
	59	unsigned long status;
	60
	61	/* New thread loses kernel privileges. */
bbaf238b	62	status = regs->cp0_status & ~(ST0_CU0\|ST0_CU1\|ST0_FR\|KU_MASK);
875d43e7	63	#ifdef CONFIG_64BIT
293c5bd1	64	status \|= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR;
1da177e4 LT	65	#endif
	66	status \|= KU_USER;
	67	regs->cp0_status = status;
	68	clear_used_math();
e04582b7	69	clear_fpu_owner();
e50c0a8f RB	70	if (cpu_has_dsp)
e50c0a8f RB	71	__init_dsp();
1da177e4 LT	72	regs->cp0_epc = pc;
1da177e4 LT	73	regs->regs[29] = sp;
1da177e4 LT	74	}
	75
	76	void exit_thread(void)
	77	{
	78	}
	79
	80	void flush_thread(void)
	81	{
	82	}
	83
6f2c55b8	84	int copy_thread(unsigned long clone_flags, unsigned long usp,
afa86fc4	85	unsigned long arg, struct task_struct *p)
1da177e4	86	{
75bb07e7	87	struct thread_info *ti = task_thread_info(p);
afa86fc4	88	struct pt_regs childregs, regs = current_pt_regs();
484889fc	89	unsigned long childksp;
3c37026d	90	p->set_child_tid = p->clear_child_tid = NULL;
1da177e4	91
75bb07e7	92	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
1da177e4 LT	93
	94	preempt_disable();
	95
e50c0a8f	96	if (is_fpu_owner())
1da177e4	97	save_fp(p);
e50c0a8f RB	98
	99	if (cpu_has_dsp)
	100	save_dsp(p);
1da177e4 LT	101
	102	preempt_enable();
	103
	104	/* set up new TSS. */
	105	childregs = (struct pt_regs *) childksp - 1;
484889fc DD	106	/* Put the stack after the struct pt_regs. */
484889fc DD	107	childksp = (unsigned long) childregs;
8f54bcac AV	108	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2\|ST0_CU1);
	109	if (unlikely(p->flags & PF_KTHREAD)) {
	110	unsigned long status = p->thread.cp0_status;
	111	memset(childregs, 0, sizeof(struct pt_regs));
	112	ti->addr_limit = KERNEL_DS;
	113	p->thread.reg16 = usp; /* fn */
	114	p->thread.reg17 = arg;
	115	p->thread.reg29 = childksp;
	116	p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
	117	#if defined(CONFIG_CPU_R3000) \|\| defined(CONFIG_CPU_TX39XX)
	118	status = (status & ~(ST0_KUP \| ST0_IEP \| ST0_IEC)) \|
	119	((status & (ST0_KUC \| ST0_IEC)) << 2);
	120	#else
	121	status \|= ST0_EXL;
	122	#endif
	123	childregs->cp0_status = status;
	124	return 0;
	125	}
1da177e4	126	childregs = regs;
70342287 RB	127	childregs->regs[7] = 0; /* Clear error flag */
70342287 RB	128	childregs->regs[2] = 0; /* Child gets zero as return value */
64b3122d AV	129	if (usp)
64b3122d AV	130	childregs->regs[29] = usp;
8f54bcac	131	ti->addr_limit = USER_DS;
1da177e4	132
1da177e4 LT	133	p->thread.reg29 = (unsigned long) childregs;
	134	p->thread.reg31 = (unsigned long) ret_from_fork;
	135
	136	/*
	137	* New tasks lose permission to use the fpu. This accelerates context
	138	* switching for most programs since they don't use the fpu.
	139	*/
1da177e4	140	childregs->cp0_status &= ~(ST0_CU2\|ST0_CU1);
1da177e4	141
9cc12363	142	#ifdef CONFIG_MIPS_MT_SMTC
f088fc84	143	/*
9cc12363 KK	144	* SMTC restores TCStatus after Status, and the CU bits
9cc12363 KK	145	* are aliased there.
f088fc84	146	*/
9cc12363 KK	147	childregs->cp0_tcstatus &= ~(ST0_CU2\|ST0_CU1);
9cc12363 KK	148	#endif
1da177e4 LT	149	clear_tsk_thread_flag(p, TIF_USEDFPU);
1da177e4 LT	150
f088fc84	151	#ifdef CONFIG_MIPS_MT_FPAFF
6657fe0a	152	clear_tsk_thread_flag(p, TIF_FPUBOUND);
f088fc84 RB	153	#endif /* CONFIG_MIPS_MT_FPAFF */
f088fc84 RB	154
3c37026d RB	155	if (clone_flags & CLONE_SETTLS)
	156	ti->tp_value = regs->regs[7];
	157
1da177e4 LT	158	return 0;
	159	}
	160
	161	/* Fill in the fpu structure for a core dump.. */
	162	int dump_fpu(struct pt_regs regs, elf_fpregset_t r)
	163	{
	164	memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));
	165
	166	return 1;
	167	}
	168
d56efda4	169	void elf_dump_regs(elf_greg_t gp, struct pt_regs regs)
1da177e4 LT	170	{
	171	int i;
	172
	173	for (i = 0; i < EF_R0; i++)
	174	gp[i] = 0;
	175	gp[EF_R0] = 0;
	176	for (i = 1; i <= 31; i++)
	177	gp[EF_R0 + i] = regs->regs[i];
	178	gp[EF_R26] = 0;
	179	gp[EF_R27] = 0;
	180	gp[EF_LO] = regs->lo;
	181	gp[EF_HI] = regs->hi;
	182	gp[EF_CP0_EPC] = regs->cp0_epc;
	183	gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
	184	gp[EF_CP0_STATUS] = regs->cp0_status;
	185	gp[EF_CP0_CAUSE] = regs->cp0_cause;
	186	#ifdef EF_UNUSED0
	187	gp[EF_UNUSED0] = 0;
	188	#endif
	189	}
	190
49a89efb	191	int dump_task_regs(struct task_struct tsk, elf_gregset_t regs)
71e0e556	192	{
40bc9c67	193	elf_dump_regs(*regs, task_pt_regs(tsk));
71e0e556 RB	194	return 1;
	195	}
	196
49a89efb	197	int dump_task_fpu(struct task_struct t, elf_fpregset_t fpr)
1da177e4 LT	198	{
	199	memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
	200
	201	return 1;
	202	}
	203
b5943182 FBH	204	/*
	205	*
	206	*/
	207	struct mips_frame_info {
	208	void *func;
	209	unsigned long func_size;
	210	int frame_size;
	211	int pc_offset;
	212	};
dc953df1	213
5000653e TW	214	#define J_TARGET(pc,target) \
	215	(((unsigned long)(pc) & 0xf0000000) \| ((target) << 2))
	216
c0efbb6d FBH	217	static inline int is_ra_save_ins(union mips_instruction *ip)
c0efbb6d FBH	218	{
34c2f668 LY	219	#ifdef CONFIG_CPU_MICROMIPS
	220	union mips_instruction mmi;
	221
	222	/*
	223	* swsp ra,offset
	224	* swm16 reglist,offset(sp)
	225	* swm32 reglist,offset(sp)
	226	* sw32 ra,offset(sp)
	227	* jradiussp - NOT SUPPORTED
	228	*
	229	* microMIPS is way more fun...
	230	*/
	231	if (mm_insn_16bit(ip->halfword[0])) {
	232	mmi.word = (ip->halfword[0] << 16);
	233	return ((mmi.mm16_r5_format.opcode == mm_swsp16_op &&
	234	mmi.mm16_r5_format.rt == 31) \|\|
	235	(mmi.mm16_m_format.opcode == mm_pool16c_op &&
	236	mmi.mm16_m_format.func == mm_swm16_op));
	237	}
	238	else {
	239	mmi.halfword[0] = ip->halfword[1];
	240	mmi.halfword[1] = ip->halfword[0];
	241	return ((mmi.mm_m_format.opcode == mm_pool32b_op &&
	242	mmi.mm_m_format.rd > 9 &&
	243	mmi.mm_m_format.base == 29 &&
	244	mmi.mm_m_format.func == mm_swm32_func) \|\|
	245	(mmi.i_format.opcode == mm_sw32_op &&
	246	mmi.i_format.rs == 29 &&
	247	mmi.i_format.rt == 31));
	248	}
	249	#else
c0efbb6d FBH	250	/* sw / sd $ra, offset($sp) */
	251	return (ip->i_format.opcode == sw_op \|\| ip->i_format.opcode == sd_op) &&
	252	ip->i_format.rs == 29 &&
	253	ip->i_format.rt == 31;
34c2f668	254	#endif
c0efbb6d FBH	255	}
c0efbb6d FBH	256
e7438c4b	257	static inline int is_jump_ins(union mips_instruction *ip)
c0efbb6d	258	{
34c2f668 LY	259	#ifdef CONFIG_CPU_MICROMIPS
	260	/*
	261	* jr16,jrc,jalr16,jalr16
	262	* jal
	263	* jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
	264	* jraddiusp - NOT SUPPORTED
	265	*
	266	* microMIPS is kind of more fun...
	267	*/
	268	union mips_instruction mmi;
	269
	270	mmi.word = (ip->halfword[0] << 16);
	271
	272	if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&
	273	(mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) \|\|
	274	ip->j_format.opcode == mm_jal32_op)
	275	return 1;
	276	if (ip->r_format.opcode != mm_pool32a_op \|\|
	277	ip->r_format.func != mm_pool32axf_op)
	278	return 0;
	279	return (((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op);
	280	#else
e7438c4b TW	281	if (ip->j_format.opcode == j_op)
e7438c4b TW	282	return 1;
c0efbb6d FBH	283	if (ip->j_format.opcode == jal_op)
	284	return 1;
	285	if (ip->r_format.opcode != spec_op)
	286	return 0;
	287	return ip->r_format.func == jalr_op \|\| ip->r_format.func == jr_op;
34c2f668	288	#endif
c0efbb6d FBH	289	}
	290
	291	static inline int is_sp_move_ins(union mips_instruction *ip)
	292	{
34c2f668 LY	293	#ifdef CONFIG_CPU_MICROMIPS
	294	/*
	295	* addiusp -imm
	296	* addius5 sp,-imm
	297	* addiu32 sp,sp,-imm
	298	* jradiussp - NOT SUPPORTED
	299	*
	300	* microMIPS is not more fun...
	301	*/
	302	if (mm_insn_16bit(ip->halfword[0])) {
	303	union mips_instruction mmi;
	304
	305	mmi.word = (ip->halfword[0] << 16);
	306	return ((mmi.mm16_r3_format.opcode == mm_pool16d_op &&
	307	mmi.mm16_r3_format.simmediate && mm_addiusp_func) \|\|
	308	(mmi.mm16_r5_format.opcode == mm_pool16d_op &&
	309	mmi.mm16_r5_format.rt == 29));
	310	}
	311	return (ip->mm_i_format.opcode == mm_addiu32_op &&
	312	ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29);
	313	#else
c0efbb6d FBH	314	/* addiu/daddiu sp,sp,-imm */
	315	if (ip->i_format.rs != 29 \|\| ip->i_format.rt != 29)
	316	return 0;
	317	if (ip->i_format.opcode == addiu_op \|\| ip->i_format.opcode == daddiu_op)
	318	return 1;
34c2f668	319	#endif
c0efbb6d FBH	320	return 0;
	321	}
	322
f66686f7	323	static int get_frame_info(struct mips_frame_info *info)
1da177e4	324	{
34c2f668 LY	325	#ifdef CONFIG_CPU_MICROMIPS
	326	union mips_instruction ip = (void ) (((char *) info->func) - 1);
	327	#else
c0efbb6d	328	union mips_instruction *ip = info->func;
34c2f668	329	#endif
29b376ff FBH	330	unsigned max_insns = info->func_size / sizeof(union mips_instruction);
29b376ff FBH	331	unsigned i;
c0efbb6d	332
1da177e4	333	info->pc_offset = -1;
63077519	334	info->frame_size = 0;
1da177e4	335
29b376ff FBH	336	if (!ip)
	337	goto err;
	338
	339	if (max_insns == 0)
	340	max_insns = 128U; /* unknown function size */
	341	max_insns = min(128U, max_insns);
	342
c0efbb6d FBH	343	for (i = 0; i < max_insns; i++, ip++) {
c0efbb6d FBH	344
e7438c4b	345	if (is_jump_ins(ip))
63077519	346	break;
0cceb4aa FBH	347	if (!info->frame_size) {
0cceb4aa FBH	348	if (is_sp_move_ins(ip))
34c2f668 LY	349	{
	350	#ifdef CONFIG_CPU_MICROMIPS
	351	if (mm_insn_16bit(ip->halfword[0]))
	352	{
	353	unsigned short tmp;
	354
	355	if (ip->halfword[0] & mm_addiusp_func)
	356	{
	357	tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
	358	info->frame_size = -(signed short)(tmp \| ((tmp & 0x100) ? 0xfe00 : 0));
	359	} else {
	360	tmp = (ip->halfword[0] >> 1);
	361	info->frame_size = -(signed short)(tmp & 0xf);
	362	}
	363	ip = (void *) &ip->halfword[1];
	364	ip--;
	365	} else
	366	#endif
0cceb4aa	367	info->frame_size = - ip->i_format.simmediate;
34c2f668	368	}
0cceb4aa	369	continue;
63077519	370	}
0cceb4aa	371	if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
63077519 AN	372	info->pc_offset =
63077519 AN	373	ip->i_format.simmediate / sizeof(long);
0cceb4aa	374	break;
1da177e4 LT	375	}
1da177e4 LT	376	}
f66686f7 AN	377	if (info->frame_size && info->pc_offset >= 0) /* nested */
	378	return 0;
	379	if (info->pc_offset < 0) /* leaf */
	380	return 1;
	381	/* prologue seems boggus... */
29b376ff	382	err:
f66686f7	383	return -1;
1da177e4 LT	384	}
1da177e4 LT	385
b5943182 FBH	386	static struct mips_frame_info schedule_mfi __read_mostly;
b5943182 FBH	387
5000653e TW	388	#ifdef CONFIG_KALLSYMS
	389	static unsigned long get___schedule_addr(void)
	390	{
	391	return kallsyms_lookup_name("__schedule");
	392	}
	393	#else
	394	static unsigned long get___schedule_addr(void)
	395	{
	396	union mips_instruction ip = (void )schedule;
	397	int max_insns = 8;
	398	int i;
	399
	400	for (i = 0; i < max_insns; i++, ip++) {
	401	if (ip->j_format.opcode == j_op)
	402	return J_TARGET(ip, ip->j_format.target);
	403	}
	404	return 0;
	405	}
	406	#endif
	407
1da177e4 LT	408	static int __init frame_info_init(void)
1da177e4 LT	409	{
b5943182	410	unsigned long size = 0;
63077519	411	#ifdef CONFIG_KALLSYMS
b5943182	412	unsigned long ofs;
5000653e TW	413	#endif
5000653e TW	414	unsigned long addr;
b5943182	415
5000653e TW	416	addr = get___schedule_addr();
	417	if (!addr)
	418	addr = (unsigned long)schedule;
	419
	420	#ifdef CONFIG_KALLSYMS
	421	kallsyms_lookup_size_offset(addr, &size, &ofs);
63077519	422	#endif
5000653e	423	schedule_mfi.func = (void *)addr;
b5943182 FBH	424	schedule_mfi.func_size = size;
	425
	426	get_frame_info(&schedule_mfi);
6057a798 FBH	427
	428	/*
	429	* Without schedule() frame info, result given by
	430	* thread_saved_pc() and get_wchan() are not reliable.
	431	*/
b5943182	432	if (schedule_mfi.pc_offset < 0)
6057a798	433	printk("Can't analyze schedule() prologue at %p\n", schedule);
63077519	434
1da177e4 LT	435	return 0;
	436	}
	437
	438	arch_initcall(frame_info_init);
	439
	440	/*
	441	* Return saved PC of a blocked thread.
	442	*/
	443	unsigned long thread_saved_pc(struct task_struct *tsk)
	444	{
	445	struct thread_struct *t = &tsk->thread;
	446
	447	/* New born processes are a special case */
	448	if (t->reg31 == (unsigned long) ret_from_fork)
	449	return t->reg31;
b5943182	450	if (schedule_mfi.pc_offset < 0)
1da177e4	451	return 0;
b5943182	452	return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
1da177e4 LT	453	}
1da177e4 LT	454
1da177e4	455
f66686f7	456	#ifdef CONFIG_KALLSYMS
94ea09c6 DK	457	/* generic stack unwinding function */
	458	unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
	459	unsigned long *sp,
	460	unsigned long pc,
	461	unsigned long *ra)
f66686f7	462	{
f66686f7	463	struct mips_frame_info info;
f66686f7	464	unsigned long size, ofs;
4d157d5e	465	int leaf;
1924600c AN	466	extern void ret_from_irq(void);
1924600c AN	467	extern void ret_from_exception(void);
f66686f7	468
f66686f7 AN	469	if (!stack_page)
	470	return 0;
	471
1924600c AN	472	/*
	473	* If we reached the bottom of interrupt context,
	474	* return saved pc in pt_regs.
	475	*/
	476	if (pc == (unsigned long)ret_from_irq \|\|
	477	pc == (unsigned long)ret_from_exception) {
	478	struct pt_regs *regs;
	479	if (*sp >= stack_page &&
	480	sp + sizeof(regs) <= stack_page + THREAD_SIZE - 32) {
	481	regs = (struct pt_regs )sp;
	482	pc = regs->cp0_epc;
	483	if (__kernel_text_address(pc)) {
	484	*sp = regs->regs[29];
	485	*ra = regs->regs[31];
	486	return pc;
	487	}
	488	}
	489	return 0;
	490	}
55b74283	491	if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
f66686f7	492	return 0;
1fd69098	493	/*
25985edc	494	* Return ra if an exception occurred at the first instruction
1fd69098	495	*/
1924600c AN	496	if (unlikely(ofs == 0)) {
	497	pc = *ra;
	498	*ra = 0;
	499	return pc;
	500	}
f66686f7 AN	501
	502	info.func = (void *)(pc - ofs);
	503	info.func_size = ofs; /* analyze from start to ofs */
4d157d5e FBH	504	leaf = get_frame_info(&info);
4d157d5e FBH	505	if (leaf < 0)
f66686f7	506	return 0;
4d157d5e FBH	507
	508	if (*sp < stack_page \|\|
	509	*sp + info.frame_size > stack_page + THREAD_SIZE - 32)
f66686f7 AN	510	return 0;
f66686f7 AN	511
4d157d5e FBH	512	if (leaf)
	513	/*
	514	* For some extreme cases, get_frame_info() can
	515	* consider wrongly a nested function as a leaf
	516	* one. In that cases avoid to return always the
	517	* same value.
	518	*/
1924600c	519	pc = pc != ra ? ra : 0;
4d157d5e FBH	520	else
	521	pc = ((unsigned long )(sp))[info.pc_offset];
	522
	523	*sp += info.frame_size;
1924600c	524	*ra = 0;
4d157d5e	525	return __kernel_text_address(pc) ? pc : 0;
f66686f7	526	}
94ea09c6 DK	527	EXPORT_SYMBOL(unwind_stack_by_address);
	528
	529	/* used by show_backtrace() */
	530	unsigned long unwind_stack(struct task_struct task, unsigned long sp,
	531	unsigned long pc, unsigned long *ra)
	532	{
	533	unsigned long stack_page = (unsigned long)task_stack_page(task);
	534	return unwind_stack_by_address(stack_page, sp, pc, ra);
	535	}
f66686f7	536	#endif
b5943182 FBH	537
	538	/*
	539	* get_wchan - a maintenance nightmare^W^Wpain in the ass ...
	540	*/
	541	unsigned long get_wchan(struct task_struct *task)
	542	{
	543	unsigned long pc = 0;
	544	#ifdef CONFIG_KALLSYMS
	545	unsigned long sp;
1924600c	546	unsigned long ra = 0;
b5943182 FBH	547	#endif
	548
	549	if (!task \|\| task == current \|\| task->state == TASK_RUNNING)
	550	goto out;
	551	if (!task_stack_page(task))
	552	goto out;
	553
	554	pc = thread_saved_pc(task);
	555
	556	#ifdef CONFIG_KALLSYMS
	557	sp = task->thread.reg29 + schedule_mfi.frame_size;
	558
	559	while (in_sched_functions(pc))
1924600c	560	pc = unwind_stack(task, &sp, pc, &ra);
b5943182 FBH	561	#endif
	562
	563	out:
	564	return pc;
	565	}
94109102 FBH	566
	567	/*
	568	* Don't forget that the stack pointer must be aligned on a 8 bytes
	569	* boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
	570	*/
	571	unsigned long arch_align_stack(unsigned long sp)
	572	{
	573	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
	574	sp -= get_random_int() & ~PAGE_MASK;
	575
	576	return sp & ALMASK;
	577	}