linux/arch/unicore32/kernel/traps.c

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/*
* linux/arch/unicore32/kernel/traps.c
*
* Code specific to PKUnity SoC and UniCore ISA
*
* Copyright (C) 2001-2010 GUAN Xue-tao
*
* 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.
* Mostly a debugging aid, but will probably kill the offending process.
*/
#include <linux/module.h>
#include <linux/signal.h>
#include <linux/spinlock.h>
#include <linux/personality.h>
#include <linux/kallsyms.h>
#include <linux/kdebug.h>
#include <linux/uaccess.h>
#include <linux/delay.h>
#include <linux/hardirq.h>
#include <linux/init.h>
#include <linux/atomic.h>
#include <linux/unistd.h>
#include <asm/cacheflush.h>
#include <asm/traps.h>
#include "setup.h"
static void dump_mem(const char *, const char *, unsigned long, unsigned long);
void dump_backtrace_entry(unsigned long where,
unsigned long from, unsigned long frame)
{
#ifdef CONFIG_KALLSYMS
printk(KERN_DEFAULT "[<%08lx>] (%pS) from [<%08lx>] (%pS)\n",
where, (void *)where, from, (void *)from);
#else
printk(KERN_DEFAULT "Function entered at [<%08lx>] from [<%08lx>]\n",
where, from);
#endif
}
/*
* 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 != NULL))
return -EFAULT;
return 0;
}
/*
* Dump out the contents of some memory nicely...
*/
static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
unsigned long top)
{
unsigned long first;
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(KERN_DEFAULT "%s%s(0x%08lx to 0x%08lx)\n",
lvl, str, bottom, top);
for (first = bottom & ~31; first < top; first += 32) {
unsigned long p;
char str[sizeof(" 12345678") * 8 + 1];
memset(str, ' ', sizeof(str));
str[sizeof(str) - 1] = '\0';
for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
if (p >= bottom && p < top) {
unsigned long val;
if (__get_user(val, (unsigned long *)p) == 0)
sprintf(str + i * 9, " %08lx", val);
else
sprintf(str + i * 9, " ????????");
}
}
printk(KERN_DEFAULT "%s%04lx:%s\n", lvl, first & 0xffff, str);
}
set_fs(fs);
}
static void dump_instr(const char *lvl, struct pt_regs *regs)
{
unsigned long addr = instruction_pointer(regs);
const int width = 8;
mm_segment_t fs;
char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
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);
for (i = -4; i < 1; i++) {
unsigned int val, bad;
bad = __get_user(val, &((u32 *)addr)[i]);
if (!bad)
p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
width, val);
else {
p += sprintf(p, "bad PC value");
break;
}
}
printk(KERN_DEFAULT "%sCode: %s\n", lvl, str);
set_fs(fs);
}
static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
{
unsigned int fp, mode;
int ok = 1;
printk(KERN_DEFAULT "Backtrace: ");
if (!tsk)
tsk = current;
if (regs) {
fp = regs->UCreg_fp;
mode = processor_mode(regs);
} else if (tsk != current) {
fp = thread_saved_fp(tsk);
mode = 0x10;
} else {
asm("mov %0, fp" : "=r" (fp) : : "cc");
mode = 0x10;
}
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)end_of_stack(tsk))
printk("frame pointer underflow");
printk("\n");
if (ok)
c_backtrace(fp, mode);
}
void show_stack(struct task_struct *tsk, unsigned long *sp)
{
dump_backtrace(NULL, tsk);
barrier();
}
static int __die(const char *str, int err, struct thread_info *thread,
struct pt_regs *regs)
{
struct task_struct *tsk = thread->task;
static int die_counter;
int ret;
printk(KERN_EMERG "Internal error: %s: %x [#%d]\n",
str, err, ++die_counter);
/* trap and error numbers are mostly meaningless on UniCore */
ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, \
SIGSEGV);
if (ret == NOTIFY_STOP)
return ret;
print_modules();
__show_regs(regs);
printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n",
TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
if (!user_mode(regs) || in_interrupt()) {
dump_mem(KERN_EMERG, "Stack: ", regs->UCreg_sp,
THREAD_SIZE + (unsigned long)task_stack_page(tsk));
dump_backtrace(regs, tsk);
dump_instr(KERN_EMERG, regs);
}
return ret;
}
DEFINE_SPINLOCK(die_lock);
/*
* This function is protected against re-entrancy.
*/
void die(const char *str, struct pt_regs *regs, int err)
{
struct thread_info *thread = current_thread_info();
int ret;
oops_enter();
spin_lock_irq(&die_lock);
console_verbose();
bust_spinlocks(1);
ret = __die(str, err, thread, regs);
bust_spinlocks(0);
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
spin_unlock_irq(&die_lock);
oops_exit();
if (in_interrupt())
panic("Fatal exception in interrupt");
if (panic_on_oops)
panic("Fatal exception");
if (ret != NOTIFY_STOP)
do_exit(SIGSEGV);
}
void uc32_notify_die(const char *str, struct pt_regs *regs,
struct siginfo *info, unsigned long err, unsigned long trap)
{
if (user_mode(regs)) {
current->thread.error_code = err;
current->thread.trap_no = trap;
force_sig_info(info->si_signo, info, current);
} else
die(str, regs, err);
}
/*
* 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, unsigned int reason)
{
console_verbose();
printk(KERN_CRIT "Bad mode detected with reason 0x%x\n", reason);
die("Oops - bad mode", regs, 0);
local_irq_disable();
panic("bad mode");
}
void __pte_error(const char *file, int line, unsigned long val)
{
printk(KERN_DEFAULT "%s:%d: bad pte %08lx.\n", file, line, val);
}
void __pmd_error(const char *file, int line, unsigned long val)
{
printk(KERN_DEFAULT "%s:%d: bad pmd %08lx.\n", file, line, val);
}
void __pgd_error(const char *file, int line, unsigned long val)
{
printk(KERN_DEFAULT "%s:%d: bad pgd %08lx.\n", file, line, val);
}
asmlinkage void __div0(void)
{
printk(KERN_DEFAULT "Division by zero in kernel.\n");
dump_stack();
}
EXPORT_SYMBOL(__div0);
void abort(void)
{
BUG();
/* if that doesn't kill us, halt */
panic("Oops failed to kill thread");
}
EXPORT_SYMBOL(abort);
void __init trap_init(void)
{
return;
}
void __init early_trap_init(void)
{
unsigned long vectors = VECTORS_BASE;
/*
* Copy the vectors, stubs (in entry-unicore.S)
* into the vector page, mapped at 0xffff0000, and ensure these
* are visible to the instruction stream.
*/
memcpy((void *)vectors,
__vectors_start,
__vectors_end - __vectors_start);
memcpy((void *)vectors + 0x200,
__stubs_start,
__stubs_end - __stubs_start);
early_signal_init();
flush_icache_range(vectors, vectors + PAGE_SIZE);
}