/*
* linux/arch/arm26/kernel/traps.c
*
* Copyright (C) 1995-2002 Russell King
* Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
* Copyright (C) 2003 Ian Molton (ARM26)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 'traps.c' handles hardware exceptions after we have saved some state in
* 'linux/arch/arm26/lib/traps.S'. Mostly a debugging aid, but will probably
* kill the offending process.
*/
#include <linux/module.h>
#include <linux/config.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/personality.h>
#include <linux/ptrace.h>
#include <linux/elf.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <asm/atomic.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/semaphore.h>
#include "ptrace.h"
extern void c_backtrace (unsigned long fp, int pmode);
extern void show_pte(struct mm_struct *mm, unsigned long addr);
const char *processor_modes[] = { "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" };
static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" "*bad reason*"};
/*
* Stack pointers should always be within the kernels view of
* physical memory. If it is not there, then we can't dump
* out any information relating to the stack.
*/
static int verify_stack(unsigned long sp)
{
if (sp < PAGE_OFFSET || (sp > (unsigned long)high_memory && high_memory != 0))
return -EFAULT;
return 0;
}
/*
* Dump out the contents of some memory nicely...
*/
static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
{
unsigned long p = bottom & ~31;
mm_segment_t fs;
int i;
/*
* We need to switch to kernel mode so that we can use __get_user
* to safely read from kernel space. Note that we now dump the
* code first, just in case the backtrace kills us.
*/
fs = get_fs();
set_fs(KERNEL_DS);
printk("%s", str);
printk("(0x%08lx to 0x%08lx)\n", 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 {
__get_user(val, (unsigned long *)p);
printk("%08x ", val);
}
}
printk ("\n");
}
set_fs(fs);
}
static void dump_instr(struct pt_regs *regs)
{
unsigned long addr = instruction_pointer(regs);
const int width = 8;
mm_segment_t fs;
int i;
/*
* We need to switch to kernel mode so that we can use __get_user
* to safely read from kernel space. Note that we now dump the
* code first, just in case the backtrace kills us.
*/
fs = get_fs();
set_fs(KERNEL_DS);
printk("Code: ");
for (i = -4; i < 1; i++) {
unsigned int val, bad;
bad = __get_user(val, &((u32 *)addr)[i]);
if (!bad)
printk(i == 0 ? "(%0*x) " : "%0*x ", width, val);
else {
printk("bad PC value.");
break;
}
}
printk("\n");
set_fs(fs);
}
/*static*/ void __dump_stack(struct task_struct *tsk, unsigned long sp)
{
dump_mem("Stack: ", sp, 8192+(unsigned long)tsk->thread_info);
}
void dump_stack(void)
{
#ifdef CONFIG_DEBUG_ERRORS
__backtrace();
#endif
}
EXPORT_SYMBOL(dump_stack);
//FIXME - was a static fn
void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
{
unsigned int fp;
int ok = 1;
printk("Backtrace: ");
fp = regs->ARM_fp;
if (!fp) {
printk("no frame pointer");
ok = 0;
} else if (verify_stack(fp)) {
printk("invalid frame pointer 0x%08x", fp);
ok = 0;
} else if (fp < (unsigned long)(tsk->thread_info + 1))
printk("frame pointer underflow");
printk("\n");
if (ok)
c_backtrace(fp, processor_mode(regs));
}
/* FIXME - this is probably wrong.. */
void show_stack(struct task_struct *task, unsigned long *sp) {
dump_mem("Stack: ", (unsigned long)sp, 8192+(unsigned long)task->thread_info);
}
DEFINE_SPINLOCK(die_lock);
/*
* This function is protected against re-entrancy.
*/
NORET_TYPE void die(const char *str, struct pt_regs *regs, int err)
{
struct task_struct *tsk = current;
console_verbose();
spin_lock_irq(&die_lock);
printk("Internal error: %s: %x\n", str, err);
printk("CPU: %d\n", smp_processor_id());
show_regs(regs);
printk("Process %s (pid: %d, stack limit = 0x%p)\n",
current->comm, current->pid, tsk->thread_info + 1);
if (!user_mode(regs) || in_interrupt()) {
__dump_stack(tsk, (unsigned long)(regs + 1));
dump_backtrace(regs, tsk);
dump_instr(regs);
}
while(1);
spin_unlock_irq(&die_lock);
do_exit(SIGSEGV);
}
void die_if_kernel(const char *str, struct pt_regs *regs, int err)
{
if (user_mode(regs))
return;
die(str, regs, err);
}
static DECLARE_MUTEX(undef_sem);
static int (*undef_hook)(struct pt_regs *);
int request_undef_hook(int (*fn)(struct pt_regs *))
{
int ret = -EBUSY;
down(&undef_sem);
if (undef_hook == NULL) {
undef_hook = fn;
ret = 0;
}
up(&undef_sem);
return ret;
}
int release_undef_hook(int (*fn)(struct pt_regs *))
{
int ret = -EINVAL;
down(&undef_sem);
if (undef_hook == fn) {
undef_hook = NULL;
ret = 0;
}
up(&undef_sem);
return ret;
}
static int undefined_extension(struct pt_regs *regs, unsigned int op)
{
switch (op) {
case 1: /* 0xde01 / 0x?7f001f0 */
ptrace_break(current, regs);
return 0;
}
return 1;
}
asmlinkage void do_undefinstr(struct pt_regs *regs)
{
siginfo_t info;
void *pc;
regs->ARM_pc -= 4;
pc = (unsigned long *)instruction_pointer(regs); /* strip PSR */
if (user_mode(regs)) {
u32 instr;
get_user(instr, (u32 *)pc);
if ((instr & 0x0fff00ff) == 0x07f000f0 &&
undefined_extension(regs, (instr >> 8) & 255) == 0) {
regs->ARM_pc += 4;
return;
}
} else {
if (undef_hook && undef_hook(regs) == 0) {
regs->ARM_pc += 4;
return;
}
}
#ifdef CONFIG_DEBUG_USER
printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",
current->comm, current->pid, pc);
dump_instr(regs);
#endif
current->thread.error_code = 0;
current->thread.trap_no = 6;
info.si_signo = SIGILL;
info.si_errno = 0;
info.si_code = ILL_ILLOPC;
info.si_addr = pc;
force_sig_info(SIGILL, &info, current);
die_if_kernel("Oops - undefined instruction", regs, 0);
}
asmlinkage void do_excpt(unsigned long address, struct pt_regs *regs, int mode)
{
siginfo_t info;
#ifdef CONFIG_DEBUG_USER
printk(KERN_INFO "%s (%d): address exception: pc=%08lx\n",
current->comm, current->pid, instruction_pointer(regs));
dump_instr(regs);
#endif
current->thread.error_code = 0;
current->thread.trap_no = 11;
info.si_signo = SIGBUS;
info.si_errno = 0;
info.si_code = BUS_ADRERR;
info.si_addr = (void *)address;
force_sig_info(SIGBUS, &info, current);
die_if_kernel("Oops - address exception", regs, mode);
}
asmlinkage void do_unexp_fiq (struct pt_regs *regs)
{
#ifndef CONFIG_IGNORE_FIQ
printk("Hmm. Unexpected FIQ received, but trying to continue\n");
printk("You may have a hardware problem...\n");
#endif
}
/*
* bad_mode handles the impossible case in the vectors. If you see one of
* these, then it's extremely serious, and could mean you have buggy hardware.
* It never returns, and never tries to sync. We hope that we can at least
* dump out some state information...
*/
asmlinkage void bad_mode(struct pt_regs *regs, int reason, int proc_mode)
{
unsigned int vectors = vectors_base();
console_verbose();
printk(KERN_CRIT "Bad mode in %s handler detected: mode %s\n",
handler[reason<5?reason:4], processor_modes[proc_mode]);
/*
* Dump out the vectors and stub routines. Maybe a better solution
* would be to dump them out only if we detect that they are corrupted.
*/
dump_mem(KERN_CRIT "Vectors: ", vectors, vectors + 0x40);
dump_mem(KERN_CRIT "Stubs: ", vectors + 0x200, vectors + 0x4b8);
die("Oops", regs, 0);
local_irq_disable();
panic("bad mode");
}
static int bad_syscall(int n, struct pt_regs *regs)
{
struct thread_info *thread = current_thread_info();
siginfo_t info;
if (current->personality != PER_LINUX && thread->exec_domain->handler) {
thread->exec_domain->handler(n, regs);
return regs->ARM_r0;
}
#ifdef CONFIG_DEBUG_USER
printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n",
current->pid, current->comm, n);
dump_instr(regs);
#endif
info.si_signo = SIGILL;
info.si_errno = 0;
info.si_code = ILL_ILLTRP;
info.si_addr = (void *)instruction_pointer(regs) - 4;
force_sig_info(SIGILL, &info, current);
die_if_kernel("Oops", regs, n);
return regs->ARM_r0;
}
static inline void
do_cache_op(unsigned long start, unsigned long end, int flags)
{
struct vm_area_struct *vma;
if (end < start)
return;
vma = find_vma(current->active_mm, start);
if (vma && vma->vm_start < end) {
if (start < vma->vm_start)
start = vma->vm_start;
if (end > vma->vm_end)
end = vma->vm_end;
}
}
/*
* Handle all unrecognised system calls.
* 0x9f0000 - 0x9fffff are some more esoteric system calls
*/
#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
asmlinkage int arm_syscall(int no, struct pt_regs *regs)
{
siginfo_t info;
if ((no >> 16) != 0x9f)
return bad_syscall(no, regs);
switch (no & 0xffff) {
case 0: /* branch through 0 */
info.si_signo = SIGSEGV;
info.si_errno = 0;
info.si_code = SEGV_MAPERR;
info.si_addr = NULL;
force_sig_info(SIGSEGV, &info, current);
die_if_kernel("branch through zero", regs, 0);
return 0;
case NR(breakpoint): /* SWI BREAK_POINT */
ptrace_break(current, regs);
return regs->ARM_r0;
case NR(cacheflush):
return 0;
case NR(usr26):
break;
default:
/* Calls 9f00xx..9f07ff are defined to return -ENOSYS
if not implemented, rather than raising SIGILL. This
way the calling program can gracefully determine whether
a feature is supported. */
if (no <= 0x7ff)
return -ENOSYS;
break;
}
#ifdef CONFIG_DEBUG_USER
/*
* experience shows that these seem to indicate that
* something catastrophic has happened
*/
printk("[%d] %s: arm syscall %d\n", current->pid, current->comm, no);
dump_instr(regs);
if (user_mode(regs)) {
show_regs(regs);
c_backtrace(regs->ARM_fp, processor_mode(regs));
}
#endif
info.si_signo = SIGILL;
info.si_errno = 0;
info.si_code = ILL_ILLTRP;
info.si_addr = (void *)instruction_pointer(regs) - 4;
force_sig_info(SIGILL, &info, current);
die_if_kernel("Oops", regs, no);
return 0;
}
void __bad_xchg(volatile void *ptr, int size)
{
printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
__builtin_return_address(0), ptr, size);
BUG();
}
/*
* A data abort trap was taken, but we did not handle the instruction.
* Try to abort the user program, or panic if it was the kernel.
*/
asmlinkage void
baddataabort(int code, unsigned long instr, struct pt_regs *regs)
{
unsigned long addr = instruction_pointer(regs);
siginfo_t info;
#ifdef CONFIG_DEBUG_USER
printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n",
current->pid, current->comm, code, instr);
dump_instr(regs);
show_pte(current->mm, addr);
#endif
info.si_signo = SIGILL;
info.si_errno = 0;
info.si_code = ILL_ILLOPC;
info.si_addr = (void *)addr;
force_sig_info(SIGILL, &info, current);
die_if_kernel("unknown data abort code", regs, instr);
}
volatile void __bug(const char *file, int line, void *data)
{
printk(KERN_CRIT"kernel BUG at %s:%d!", file, line);
if (data)
printk(KERN_CRIT" - extra data = %p", data);
printk("\n");
*(int *)0 = 0;
}
void __readwrite_bug(const char *fn)
{
printk("%s called, but not implemented", fn);
BUG();
}
void __pte_error(const char *file, int line, unsigned long val)
{
printk("%s:%d: bad pte %08lx.\n", file, line, val);
}
void __pmd_error(const char *file, int line, unsigned long val)
{
printk("%s:%d: bad pmd %08lx.\n", file, line, val);
}
void __pgd_error(const char *file, int line, unsigned long val)
{
printk("%s:%d: bad pgd %08lx.\n", file, line, val);
}
asmlinkage void __div0(void)
{
printk("Division by zero in kernel.\n");
dump_stack();
}
void abort(void)
{
BUG();
/* if that doesn't kill us, halt */
panic("Oops failed to kill thread");
}
void __init trap_init(void)
{
extern void __trap_init(unsigned long);
unsigned long base = vectors_base();
__trap_init(base);
if (base != 0)
printk(KERN_DEBUG "Relocating machine vectors to 0x%08lx\n",
base);
}
