[mirror_ubuntu-artful-kernel.git] / arch / mips / kernel / process.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
 * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org)
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 * Copyright (C) 2004 Thiemo Seufer
 * 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

void arch_cpu_idle(void)
{
#ifdef CONFIG_MIPS_MT_SMTC
	extern void smtc_idle_loop_hook(void);

	smtc_idle_loop_hook();
#endif
	if (cpu_wait)
		(*cpu_wait)();
	else
		local_irq_enable();
}

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)
{
#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_jal_jalr_jr_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 == 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_jal_jalr_jr_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;

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