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6b0022305f
linux/arch/sh/kernel/traps.c
Paul Mundt 6b0022305f sh: Proper show_stack/show_trace() implementation. 
This splits out some of the previous show_stack() implementation which
was mostly doing the show_trace() work without actually dumping any of
the stack contents. This now gets split in to two sections, where we
do the fetching of the stack pointer and subsequent stack dumping in
show_stack(), while moving the call trace in to show_trace().

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2006-10-19 16:30:31 +09:00

812 lines
18 KiB
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/*
* 'traps.c' handles hardware traps and faults after we have saved some
* state in 'entry.S'.
*
* SuperH version: Copyright (C) 1999 Niibe Yutaka
* Copyright (C) 2000 Philipp Rumpf
* Copyright (C) 2000 David Howells
* Copyright (C) 2002 - 2006 Paul Mundt
*
* 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.
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/atomic.h>
#include <asm/processor.h>
#include <asm/sections.h>
#ifdef CONFIG_SH_KGDB
#include <asm/kgdb.h>
#define CHK_REMOTE_DEBUG(regs) \
{ \
if (kgdb_debug_hook && !user_mode(regs))\
(*kgdb_debug_hook)(regs); \
}
#else
#define CHK_REMOTE_DEBUG(regs)
#endif
#ifdef CONFIG_CPU_SH2
#define TRAP_RESERVED_INST 4
#define TRAP_ILLEGAL_SLOT_INST 6
#else
#define TRAP_RESERVED_INST 12
#define TRAP_ILLEGAL_SLOT_INST 13
#endif
static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
{
unsigned long p;
int i;
printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
for (p = bottom & ~31; p < top; ) {
printk("%04lx: ", p & 0xffff);
for (i = 0; i < 8; i++, p += 4) {
unsigned int val;
if (p < bottom || p >= top)
printk(" ");
else {
if (__get_user(val, (unsigned int __user *)p)) {
printk("\n");
return;
}
printk("%08x ", val);
}
}
printk("\n");
}
}
DEFINE_SPINLOCK(die_lock);
void die(const char * str, struct pt_regs * regs, long err)
{
static int die_counter;
console_verbose();
spin_lock_irq(&die_lock);
bust_spinlocks(1);
printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
CHK_REMOTE_DEBUG(regs);
print_modules();
show_regs(regs);
printk("Process: %s (pid: %d, stack limit = %p)\n",
current->comm, current->pid, task_stack_page(current) + 1);
if (!user_mode(regs) || in_interrupt())
dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
(unsigned long)task_stack_page(current));
bust_spinlocks(0);
spin_unlock_irq(&die_lock);
do_exit(SIGSEGV);
}
static inline void die_if_kernel(const char *str, struct pt_regs *regs,
long err)
{
if (!user_mode(regs))
die(str, regs, err);
}
static int handle_unaligned_notify_count = 10;
/*
* try and fix up kernelspace address errors
* - userspace errors just cause EFAULT to be returned, resulting in SEGV
* - kernel/userspace interfaces cause a jump to an appropriate handler
* - other kernel errors are bad
* - return 0 if fixed-up, -EFAULT if non-fatal (to the kernel) fault
*/
static int die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
{
if (!user_mode(regs)) {
const struct exception_table_entry *fixup;
fixup = search_exception_tables(regs->pc);
if (fixup) {
regs->pc = fixup->fixup;
return 0;
}
die(str, regs, err);
}
return -EFAULT;
}
/*
* handle an instruction that does an unaligned memory access by emulating the
* desired behaviour
* - note that PC _may not_ point to the faulting instruction
* (if that instruction is in a branch delay slot)
* - return 0 if emulation okay, -EFAULT on existential error
*/
static int handle_unaligned_ins(u16 instruction, struct pt_regs *regs)
{
int ret, index, count;
unsigned long *rm, *rn;
unsigned char *src, *dst;
index = (instruction>>8)&15; /* 0x0F00 */
rn = &regs->regs[index];
index = (instruction>>4)&15; /* 0x00F0 */
rm = &regs->regs[index];
count = 1<<(instruction&3);
ret = -EFAULT;
switch (instruction>>12) {
case 0: /* mov.[bwl] to/from memory via r0+rn */
if (instruction & 8) {
/* from memory */
src = (unsigned char*) *rm;
src += regs->regs[0];
dst = (unsigned char*) rn;
*(unsigned long*)dst = 0;
#ifdef __LITTLE_ENDIAN__
if (copy_from_user(dst, src, count))
goto fetch_fault;
if ((count == 2) && dst[1] & 0x80) {
dst[2] = 0xff;
dst[3] = 0xff;
}
#else
dst += 4-count;
if (__copy_user(dst, src, count))
goto fetch_fault;
if ((count == 2) && dst[2] & 0x80) {
dst[0] = 0xff;
dst[1] = 0xff;
}
#endif
} else {
/* to memory */
src = (unsigned char*) rm;
#if !defined(__LITTLE_ENDIAN__)
src += 4-count;
#endif
dst = (unsigned char*) *rn;
dst += regs->regs[0];
if (copy_to_user(dst, src, count))
goto fetch_fault;
}
ret = 0;
break;
case 1: /* mov.l Rm,@(disp,Rn) */
src = (unsigned char*) rm;
dst = (unsigned char*) *rn;
dst += (instruction&0x000F)<<2;
if (copy_to_user(dst,src,4))
goto fetch_fault;
ret = 0;
break;
case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
if (instruction & 4)
*rn -= count;
src = (unsigned char*) rm;
dst = (unsigned char*) *rn;
#if !defined(__LITTLE_ENDIAN__)
src += 4-count;
#endif
if (copy_to_user(dst, src, count))
goto fetch_fault;
ret = 0;
break;
case 5: /* mov.l @(disp,Rm),Rn */
src = (unsigned char*) *rm;
src += (instruction&0x000F)<<2;
dst = (unsigned char*) rn;
*(unsigned long*)dst = 0;
if (copy_from_user(dst,src,4))
goto fetch_fault;
ret = 0;
break;
case 6: /* mov.[bwl] from memory, possibly with post-increment */
src = (unsigned char*) *rm;
if (instruction & 4)
*rm += count;
dst = (unsigned char*) rn;
*(unsigned long*)dst = 0;
#ifdef __LITTLE_ENDIAN__
if (copy_from_user(dst, src, count))
goto fetch_fault;
if ((count == 2) && dst[1] & 0x80) {
dst[2] = 0xff;
dst[3] = 0xff;
}
#else
dst += 4-count;
if (copy_from_user(dst, src, count))
goto fetch_fault;
if ((count == 2) && dst[2] & 0x80) {
dst[0] = 0xff;
dst[1] = 0xff;
}
#endif
ret = 0;
break;
case 8:
switch ((instruction&0xFF00)>>8) {
case 0x81: /* mov.w R0,@(disp,Rn) */
src = (unsigned char*) &regs->regs[0];
#if !defined(__LITTLE_ENDIAN__)
src += 2;
#endif
dst = (unsigned char*) *rm; /* called Rn in the spec */
dst += (instruction&0x000F)<<1;
if (copy_to_user(dst, src, 2))
goto fetch_fault;
ret = 0;
break;
case 0x85: /* mov.w @(disp,Rm),R0 */
src = (unsigned char*) *rm;
src += (instruction&0x000F)<<1;
dst = (unsigned char*) &regs->regs[0];
*(unsigned long*)dst = 0;
#if !defined(__LITTLE_ENDIAN__)
dst += 2;
#endif
if (copy_from_user(dst, src, 2))
goto fetch_fault;
#ifdef __LITTLE_ENDIAN__
if (dst[1] & 0x80) {
dst[2] = 0xff;
dst[3] = 0xff;
}
#else
if (dst[2] & 0x80) {
dst[0] = 0xff;
dst[1] = 0xff;
}
#endif
ret = 0;
break;
}
break;
}
return ret;
fetch_fault:
/* Argh. Address not only misaligned but also non-existent.
* Raise an EFAULT and see if it's trapped
*/
return die_if_no_fixup("Fault in unaligned fixup", regs, 0);
}
/*
* emulate the instruction in the delay slot
* - fetches the instruction from PC+2
*/
static inline int handle_unaligned_delayslot(struct pt_regs *regs)
{
u16 instruction;
if (copy_from_user(&instruction, (u16 *)(regs->pc+2), 2)) {
/* the instruction-fetch faulted */
if (user_mode(regs))
return -EFAULT;
/* kernel */
die("delay-slot-insn faulting in handle_unaligned_delayslot", regs, 0);
}
return handle_unaligned_ins(instruction,regs);
}
/*
* handle an instruction that does an unaligned memory access
* - have to be careful of branch delay-slot instructions that fault
* SH3:
* - if the branch would be taken PC points to the branch
* - if the branch would not be taken, PC points to delay-slot
* SH4:
* - PC always points to delayed branch
* - return 0 if handled, -EFAULT if failed (may not return if in kernel)
*/
/* Macros to determine offset from current PC for branch instructions */
/* Explicit type coercion is used to force sign extension where needed */
#define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
#define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
static int handle_unaligned_access(u16 instruction, struct pt_regs *regs)
{
u_int rm;
int ret, index;
index = (instruction>>8)&15; /* 0x0F00 */
rm = regs->regs[index];
/* shout about the first ten userspace fixups */
if (user_mode(regs) && handle_unaligned_notify_count>0) {
handle_unaligned_notify_count--;
printk("Fixing up unaligned userspace access in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
current->comm,current->pid,(u16*)regs->pc,instruction);
}
ret = -EFAULT;
switch (instruction&0xF000) {
case 0x0000:
if (instruction==0x000B) {
/* rts */
ret = handle_unaligned_delayslot(regs);
if (ret==0)
regs->pc = regs->pr;
}
else if ((instruction&0x00FF)==0x0023) {
/* braf @Rm */
ret = handle_unaligned_delayslot(regs);
if (ret==0)
regs->pc += rm + 4;
}
else if ((instruction&0x00FF)==0x0003) {
/* bsrf @Rm */
ret = handle_unaligned_delayslot(regs);
if (ret==0) {
regs->pr = regs->pc + 4;
regs->pc += rm + 4;
}
}
else {
/* mov.[bwl] to/from memory via r0+rn */
goto simple;
}
break;
case 0x1000: /* mov.l Rm,@(disp,Rn) */
goto simple;
case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
goto simple;
case 0x4000:
if ((instruction&0x00FF)==0x002B) {
/* jmp @Rm */
ret = handle_unaligned_delayslot(regs);
if (ret==0)
regs->pc = rm;
}
else if ((instruction&0x00FF)==0x000B) {
/* jsr @Rm */
ret = handle_unaligned_delayslot(regs);
if (ret==0) {
regs->pr = regs->pc + 4;
regs->pc = rm;
}
}
else {
/* mov.[bwl] to/from memory via r0+rn */
goto simple;
}
break;
case 0x5000: /* mov.l @(disp,Rm),Rn */
goto simple;
case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
goto simple;
case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
switch (instruction&0x0F00) {
case 0x0100: /* mov.w R0,@(disp,Rm) */
goto simple;
case 0x0500: /* mov.w @(disp,Rm),R0 */
goto simple;
case 0x0B00: /* bf lab - no delayslot*/
break;
case 0x0F00: /* bf/s lab */
ret = handle_unaligned_delayslot(regs);
if (ret==0) {
#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
if ((regs->sr & 0x00000001) != 0)
regs->pc += 4; /* next after slot */
else
#endif
regs->pc += SH_PC_8BIT_OFFSET(instruction);
}
break;
case 0x0900: /* bt lab - no delayslot */
break;
case 0x0D00: /* bt/s lab */
ret = handle_unaligned_delayslot(regs);
if (ret==0) {
#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
if ((regs->sr & 0x00000001) == 0)
regs->pc += 4; /* next after slot */
else
#endif
regs->pc += SH_PC_8BIT_OFFSET(instruction);
}
break;
}
break;
case 0xA000: /* bra label */
ret = handle_unaligned_delayslot(regs);
if (ret==0)
regs->pc += SH_PC_12BIT_OFFSET(instruction);
break;
case 0xB000: /* bsr label */
ret = handle_unaligned_delayslot(regs);
if (ret==0) {
regs->pr = regs->pc + 4;
regs->pc += SH_PC_12BIT_OFFSET(instruction);
}
break;
}
return ret;
/* handle non-delay-slot instruction */
simple:
ret = handle_unaligned_ins(instruction,regs);
if (ret==0)
regs->pc += 2;
return ret;
}
/*
* Handle various address error exceptions
*/
asmlinkage void do_address_error(struct pt_regs *regs,
unsigned long writeaccess,
unsigned long address)
{
unsigned long error_code;
mm_segment_t oldfs;
u16 instruction;
int tmp;
asm volatile("stc r2_bank,%0": "=r" (error_code));
oldfs = get_fs();
if (user_mode(regs)) {
local_irq_enable();
current->thread.error_code = error_code;
current->thread.trap_no = (writeaccess) ? 8 : 7;
/* bad PC is not something we can fix */
if (regs->pc & 1)
goto uspace_segv;
set_fs(USER_DS);
if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {
/* Argh. Fault on the instruction itself.
This should never happen non-SMP
*/
set_fs(oldfs);
goto uspace_segv;
}
tmp = handle_unaligned_access(instruction, regs);
set_fs(oldfs);
if (tmp==0)
return; /* sorted */
uspace_segv:
printk(KERN_NOTICE "Killing process \"%s\" due to unaligned access\n", current->comm);
force_sig(SIGSEGV, current);
} else {
if (regs->pc & 1)
die("unaligned program counter", regs, error_code);
set_fs(KERNEL_DS);
if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {
/* Argh. Fault on the instruction itself.
This should never happen non-SMP
*/
set_fs(oldfs);
die("insn faulting in do_address_error", regs, 0);
}
handle_unaligned_access(instruction, regs);
set_fs(oldfs);
}
}
#ifdef CONFIG_SH_DSP
/*
* SH-DSP support gerg@snapgear.com.
*/
int is_dsp_inst(struct pt_regs *regs)
{
unsigned short inst;
/*
* Safe guard if DSP mode is already enabled or we're lacking
* the DSP altogether.
*/
if (!(cpu_data->flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
return 0;
get_user(inst, ((unsigned short *) regs->pc));
inst &= 0xf000;
/* Check for any type of DSP or support instruction */
if ((inst == 0xf000) || (inst == 0x4000))
return 1;
return 0;
}
#else
#define is_dsp_inst(regs) (0)
#endif /* CONFIG_SH_DSP */
extern int do_fpu_inst(unsigned short, struct pt_regs*);
asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs regs)
{
unsigned long error_code;
struct task_struct *tsk = current;
#ifdef CONFIG_SH_FPU_EMU
unsigned short inst;
int err;
get_user(inst, (unsigned short*)regs.pc);
err = do_fpu_inst(inst, &regs);
if (!err) {
regs.pc += 2;
return;
}
/* not a FPU inst. */
#endif
#ifdef CONFIG_SH_DSP
/* Check if it's a DSP instruction */
if (is_dsp_inst(&regs)) {
/* Enable DSP mode, and restart instruction. */
regs.sr |= SR_DSP;
return;
}
#endif
asm volatile("stc r2_bank, %0": "=r" (error_code));
local_irq_enable();
tsk->thread.error_code = error_code;
tsk->thread.trap_no = TRAP_RESERVED_INST;
CHK_REMOTE_DEBUG(&regs);
force_sig(SIGILL, tsk);
die_if_no_fixup("reserved instruction", &regs, error_code);
}
#ifdef CONFIG_SH_FPU_EMU
static int emulate_branch(unsigned short inst, struct pt_regs* regs)
{
/*
* bfs: 8fxx: PC+=d*2+4;
* bts: 8dxx: PC+=d*2+4;
* bra: axxx: PC+=D*2+4;
* bsr: bxxx: PC+=D*2+4 after PR=PC+4;
* braf:0x23: PC+=Rn*2+4;
* bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
* jmp: 4x2b: PC=Rn;
* jsr: 4x0b: PC=Rn after PR=PC+4;
* rts: 000b: PC=PR;
*/
if ((inst & 0xfd00) == 0x8d00) {
regs->pc += SH_PC_8BIT_OFFSET(inst);
return 0;
}
if ((inst & 0xe000) == 0xa000) {
regs->pc += SH_PC_12BIT_OFFSET(inst);
return 0;
}
if ((inst & 0xf0df) == 0x0003) {
regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
return 0;
}
if ((inst & 0xf0df) == 0x400b) {
regs->pc = regs->regs[(inst & 0x0f00) >> 8];
return 0;
}
if ((inst & 0xffff) == 0x000b) {
regs->pc = regs->pr;
return 0;
}
return 1;
}
#endif
asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs regs)
{
unsigned long error_code;
struct task_struct *tsk = current;
#ifdef CONFIG_SH_FPU_EMU
unsigned short inst;
get_user(inst, (unsigned short *)regs.pc + 1);
if (!do_fpu_inst(inst, &regs)) {
get_user(inst, (unsigned short *)regs.pc);
if (!emulate_branch(inst, &regs))
return;
/* fault in branch.*/
}
/* not a FPU inst. */
#endif
asm volatile("stc r2_bank, %0": "=r" (error_code));
local_irq_enable();
tsk->thread.error_code = error_code;
tsk->thread.trap_no = TRAP_RESERVED_INST;
CHK_REMOTE_DEBUG(&regs);
force_sig(SIGILL, tsk);
die_if_no_fixup("illegal slot instruction", &regs, error_code);
}
asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs regs)
{
long ex;
asm volatile("stc r2_bank, %0" : "=r" (ex));
die_if_kernel("exception", &regs, ex);
}
#if defined(CONFIG_SH_STANDARD_BIOS)
void *gdb_vbr_vector;
static inline void __init gdb_vbr_init(void)
{
register unsigned long vbr;
/*
* Read the old value of the VBR register to initialise
* the vector through which debug and BIOS traps are
* delegated by the Linux trap handler.
*/
asm volatile("stc vbr, %0" : "=r" (vbr));
gdb_vbr_vector = (void *)(vbr + 0x100);
printk("Setting GDB trap vector to 0x%08lx\n",
(unsigned long)gdb_vbr_vector);
}
#endif
void __init per_cpu_trap_init(void)
{
extern void *vbr_base;
#ifdef CONFIG_SH_STANDARD_BIOS
gdb_vbr_init();
#endif
/* NOTE: The VBR value should be at P1
(or P2, virtural "fixed" address space).
It's definitely should not in physical address. */
asm volatile("ldc %0, vbr"
: /* no output */
: "r" (&vbr_base)
: "memory");
}
void __init trap_init(void)
{
extern void *exception_handling_table[];
exception_handling_table[TRAP_RESERVED_INST]
= (void *)do_reserved_inst;
exception_handling_table[TRAP_ILLEGAL_SLOT_INST]
= (void *)do_illegal_slot_inst;
#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
defined(CONFIG_SH_FPU_EMU)
/*
* For SH-4 lacking an FPU, treat floating point instructions as
* reserved. They'll be handled in the math-emu case, or faulted on
* otherwise.
*/
/* entry 64 corresponds to EXPEVT=0x800 */
exception_handling_table[64] = (void *)do_reserved_inst;
exception_handling_table[65] = (void *)do_illegal_slot_inst;
#endif
/* Setup VBR for boot cpu */
per_cpu_trap_init();
}
void show_trace(struct task_struct *tsk, unsigned long *sp,
struct pt_regs *regs)
{
unsigned long addr;
if (regs && user_mode(regs))
return;
printk("\nCall trace: ");
#ifdef CONFIG_KALLSYMS
printk("\n");
#endif
while (!kstack_end(sp)) {
addr = *sp++;
if (kernel_text_address(addr))
print_ip_sym(addr);
}
printk("\n");
}
void show_stack(struct task_struct *tsk, unsigned long *sp)
{
unsigned long stack;
if (!tsk)
tsk = current;
if (tsk == current)
sp = (unsigned long *)current_stack_pointer;
else
sp = (unsigned long *)tsk->thread.sp;
stack = (unsigned long)sp;
dump_mem("Stack: ", stack, THREAD_SIZE +
(unsigned long)task_stack_page(tsk));
show_trace(tsk, sp, NULL);
}
void dump_stack(void)
{
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
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