traps.c

Go to the documentation of this file.

/*
 *  linux/arch/cris/traps.c
 *
 *  Here we handle the break vectors not used by the system call
 *  mechanism, as well as some general stack/register dumping
 *  things.
 *
 *  Copyright (C) 2000-2007 Axis Communications AB
 *
 *  Authors:   Bjorn Wesen
 *             Hans-Peter Nilsson
 *
 */

#include <linux/init.h>
#include <linux/module.h>

#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <arch/system.h>

extern void arch_enable_nmi(void);
extern void stop_watchdog(void);
extern void reset_watchdog(void);
extern void show_registers(struct pt_regs *regs);

#ifdef CONFIG_DEBUG_BUGVERBOSE
extern void handle_BUG(struct pt_regs *regs);
#else
#define handle_BUG(regs)
#endif

static int kstack_depth_to_print = 24;

void (*nmi_handler)(struct pt_regs *);

void
show_trace(unsigned long *stack)
{
    unsigned long addr, module_start, module_end;
    extern char _stext, _etext;
    int i;

    printk("\nCall Trace: ");

    i = 1;
    module_start = VMALLOC_START;
    module_end = VMALLOC_END;

    while (((long)stack & (THREAD_SIZE-1)) != 0) {
        if (__get_user(addr, stack)) {
            /* This message matches "failing address" marked
               s390 in ksymoops, so lines containing it will
               not be filtered out by ksymoops.  */
            printk("Failing address 0x%lx\n", (unsigned long)stack);
            break;
        }
        stack++;

        /*
         * If the address is either in the text segment of the
         * kernel, or in the region which contains vmalloc'ed
         * memory, it *may* be the address of a calling
         * routine; if so, print it so that someone tracing
         * down the cause of the crash will be able to figure
         * out the call path that was taken.
         */
        if (((addr >= (unsigned long)&_stext) &&
             (addr <= (unsigned long)&_etext)) ||
            ((addr >= module_start) && (addr <= module_end))) {
            if (i && ((i % 8) == 0))
                printk("\n       ");
            printk("[<%08lx>] ", addr);
            i++;
        }
    }
}

/*
 * These constants are for searching for possible module text
 * segments. MODULE_RANGE is a guess of how much space is likely
 * to be vmalloced.
 */

#define MODULE_RANGE (8*1024*1024)

/*
 * The output (format, strings and order) is adjusted to be usable with
 * ksymoops-2.4.1 with some necessary CRIS-specific patches.  Please don't
 * change it unless you're serious about adjusting ksymoops and syncing
 * with the ksymoops maintainer.
 */

void
show_stack(struct task_struct *task, unsigned long *sp)
{
    unsigned long *stack, addr;
    int i;

    /*
     * debugging aid: "show_stack(NULL);" prints a
     * back trace.
     */

    if (sp == NULL) {
        if (task)
            sp = (unsigned long*)task->thread.ksp;
        else
            sp = (unsigned long*)rdsp();
    }

    stack = sp;

    printk("\nStack from %08lx:\n       ", (unsigned long)stack);
    for (i = 0; i < kstack_depth_to_print; i++) {
        if (((long)stack & (THREAD_SIZE-1)) == 0)
            break;
        if (i && ((i % 8) == 0))
            printk("\n       ");
        if (__get_user(addr, stack)) {
            /* This message matches "failing address" marked
               s390 in ksymoops, so lines containing it will
               not be filtered out by ksymoops.  */
            printk("Failing address 0x%lx\n", (unsigned long)stack);
            break;
        }
        stack++;
        printk("%08lx ", addr);
    }
    show_trace(sp);
}

#if 0
/* displays a short stack trace */

int
show_stack(void)
{
    unsigned long *sp = (unsigned long *)rdusp();
    int i;

    printk("Stack dump [0x%08lx]:\n", (unsigned long)sp);
    for (i = 0; i < 16; i++)
        printk("sp + %d: 0x%08lx\n", i*4, sp[i]);
    return 0;
}
#endif

void
dump_stack(void)
{
    show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);

void
set_nmi_handler(void (*handler)(struct pt_regs *))
{
    nmi_handler = handler;
    arch_enable_nmi();
}

#ifdef CONFIG_DEBUG_NMI_OOPS
void
oops_nmi_handler(struct pt_regs *regs)
{
    stop_watchdog();
    oops_in_progress = 1;
    printk("NMI!\n");
    show_registers(regs);
    oops_in_progress = 0;
}

static int __init
oops_nmi_register(void)
{
    set_nmi_handler(oops_nmi_handler);
    return 0;
}

__initcall(oops_nmi_register);

#endif

/*
 * This gets called from entry.S when the watchdog has bitten. Show something
 * similar to an Oops dump, and if the kernel is configured to be a nice
 * doggy, then halt instead of reboot.
 */
void
watchdog_bite_hook(struct pt_regs *regs)
{
#ifdef CONFIG_ETRAX_WATCHDOG_NICE_DOGGY
    local_irq_disable();
    stop_watchdog();
    show_registers(regs);

    while (1)
        ; /* Do nothing. */
#else
    show_registers(regs);
#endif
}

/* This is normally the Oops function. */
void
die_if_kernel(const char *str, struct pt_regs *regs, long err)
{
    if (user_mode(regs))
        return;

#ifdef CONFIG_ETRAX_WATCHDOG_NICE_DOGGY
    /*
     * This printout might take too long and could trigger
     * the watchdog normally. If NICE_DOGGY is set, simply
     * stop the watchdog during the printout.
     */
    stop_watchdog();
#endif

    handle_BUG(regs);

    printk("%s: %04lx\n", str, err & 0xffff);

    show_registers(regs);

    oops_in_progress = 0;

#ifdef CONFIG_ETRAX_WATCHDOG_NICE_DOGGY
    reset_watchdog();
#endif
    do_exit(SIGSEGV);
}

void __init
trap_init(void)
{
    /* Nothing needs to be done */
}