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/*
* linux/arch/arm/kernel/traps.c
*
* Copyright (C) 1995, 1996 Russell King
* Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
*
* 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/arm/lib/traps.S'. Mostly a debugging aid, but will probably
* kill the offending process.
*/
#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 "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" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
"UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
"USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
"UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
};
static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" };
/*
* 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)
return -EFAULT;
return 0;
}
/*
* Dump out the contents of some memory nicely...
*/
void dump_mem(unsigned long bottom, unsigned long top)
{
unsigned long p = bottom & ~31;
int i;
for (p = bottom & ~31; p < top;) {
printk("%08lx: ", p);
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);
}
if (i == 3)
printk(" ");
}
printk ("\n");
}
}
/*
* These constants are for searching for possible module text
* segments. VMALLOC_OFFSET comes from mm/vmalloc.c; MODULE_RANGE is
* a guess of how much space is likely to be vmalloced.
*/
#define VMALLOC_OFFSET (8*1024*1024)
#define MODULE_RANGE (8*1024*1024)
static void dump_instr(struct pt_regs *regs)
{
unsigned long addr = instruction_pointer(regs);
const int thumb = thumb_mode(regs);
const int width = thumb ? 4 : 8;
int i;
printk("Code: ");
for (i = -2; i < 3; i++) {
unsigned int val, bad;
if (thumb)
bad = __get_user(val, &((u16 *)addr)[i]);
else
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");
}
static void dump_stack(struct task_struct *tsk, unsigned long sp)
{
printk("Stack:\n");
dump_mem(sp - 16, 8192+(unsigned long)tsk);
}
static 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 < 4096+(unsigned long)tsk)
printk("frame pointer underflow");
printk("\n");
if (ok)
c_backtrace(fp, processor_mode(regs));
}
/*
* This is called from SysRq-T (show_task) to display the current
* call trace for each process. Very useful.
*/
void show_trace_task(struct task_struct *tsk)
{
if (tsk != current) {
unsigned int fp = tsk->thread.save->fp;
c_backtrace(fp, 0x10);
}
}
spinlock_t die_lock = SPIN_LOCK_UNLOCKED;
/*
* 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, stackpage=%08lx)\n",
current->comm, current->pid, 4096+(unsigned long)tsk);
if (!user_mode(regs) || in_interrupt()) {
mm_segment_t fs;
/*
* 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);
dump_stack(tsk, (unsigned long)(regs + 1));
dump_backtrace(regs, tsk);
dump_instr(regs);
set_fs(fs);
}
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);
}
asmlinkage void do_undefinstr(int address, struct pt_regs *regs, int mode)
{
unsigned long *pc;
siginfo_t info;
/*
* According to the ARM ARM, PC is 2 or 4 bytes ahead, depending
* whether we're in Thumb mode or not.
*/
regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
pc = (unsigned long *)instruction_pointer(regs);
#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, mode);
}
#ifdef CONFIG_CPU_26
asmlinkage void do_excpt(int 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);
}
#endif
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();
mm_segment_t fs;
console_verbose();
printk(KERN_CRIT "Bad mode in %s handler detected: mode %s\n",
handler[reason], processor_modes[proc_mode]);
/*
* 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);
/*
* 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.
*/
printk(KERN_CRIT "Vectors:\n");
dump_mem(vectors, 0x40);
printk(KERN_CRIT "Stubs:\n");
dump_mem(vectors + 0x200, 0x4b8);
set_fs(fs);
die("Oops", regs, 0);
cli();
panic("bad mode");
}
static int bad_syscall(int n, struct pt_regs *regs)
{
siginfo_t info;
/* You might think just testing `handler' would be enough, but PER_LINUX
* points it to no_lcall7 to catch undercover SVr4 binaries. Gutted.
*/
if (current->personality != PER_LINUX && current->exec_domain->handler) {
/* Hand it off to iBCS. The extra parameter and consequent type
* forcing is necessary because of the weird ARM calling convention.
*/
current->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) -
(thumb_mode(regs) ? 2 : 4);
force_sig_info(SIGILL, &info, current);
die_if_kernel("Oops", regs, n);
return regs->ARM_r0;
}
/*
* 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 */
/*
* The PC is always left pointing at the next
* instruction. Fix this.
*/
regs->ARM_pc -= 4;
__ptrace_cancel_bpt(current);
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_BRKPT;
info.si_addr = (void *)instruction_pointer(regs) -
(thumb_mode(regs) ? 2 : 4);
force_sig_info(SIGTRAP, &info, current);
return regs->ARM_r0;
#ifdef CONFIG_CPU_32
/*
* Flush a region from virtual address 'r0' to virtual address 'r1'
* _inclusive_. There is no alignment requirement on either address;
* user space does not need to know the hardware cache layout.
*
* r2 contains flags. It should ALWAYS be passed as ZERO until it
* is defined to be something else. For now we ignore it, but may
* the fires of hell burn in your belly if you break this rule. ;)
*
* (at a later date, we may want to allow this call to not flush
* various aspects of the cache. Passing '0' will guarantee that
* everything necessary gets flushed to maintain consistency in
* the specified region).
*/
case NR(cacheflush):
cpu_cache_clean_invalidate_range(regs->ARM_r0, regs->ARM_r1, 1);
return 0;
case NR(usr26):
if (!(elf_hwcap & HWCAP_26BIT))
break;
regs->ARM_cpsr &= ~0x10;
return regs->ARM_r0;
case NR(usr32):
if (!(elf_hwcap & HWCAP_26BIT))
break;
regs->ARM_cpsr |= 0x10;
return regs->ARM_r0;
#else
case NR(cacheflush):
return 0;
case NR(usr26):
case NR(usr32):
break;
#endif
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) -
(thumb_mode(regs) ? 2 : 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);
}
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");
__backtrace();
}
void abort(void)
{
void *lr = __builtin_return_address(0);
printk(KERN_CRIT "abort() called from %p! (Please "
"report to rmk@arm.linux.org.uk)\n", lr);
BUG();
/* if that doesn't kill us, halt */
panic("Oops failed to kill thread");
}
void __init trap_init(void)
{
extern void __trap_init(void *);
__trap_init((void *)vectors_base());
if (vectors_base() != 0)
printk(KERN_DEBUG "Relocating machine vectors to 0x%08x\n",
vectors_base());
#ifdef CONFIG_CPU_32
modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
#endif
}
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