linux/arch/mips/kernel/process.c

581 lines
14 KiB
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
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;
}
#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;
}