path: root/arch/sh/kernel/traps_32.c

/*
 * '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 - 2010 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/kernel.h>
#include <linux/ptrace.h>
#include <linux/hardirq.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/io.h>
#include <linux/bug.h>
#include <linux/debug_locks.h>
#include <linux/kdebug.h>
#include <linux/kexec.h>
#include <linux/limits.h>
#include <linux/sysfs.h>
#include <linux/uaccess.h>
#include <linux/perf_event.h>
#include <asm/system.h>
#include <asm/alignment.h>
#include <asm/fpu.h>
#include <asm/kprobes.h>

#ifdef CONFIG_CPU_SH2
# define TRAP_RESERVED_INST	4
# define TRAP_ILLEGAL_SLOT_INST	6
# define TRAP_ADDRESS_ERROR	9
# ifdef CONFIG_CPU_SH2A
#  define TRAP_UBC		12
#  define TRAP_FPU_ERROR	13
#  define TRAP_DIVZERO_ERROR	17
#  define TRAP_DIVOVF_ERROR	18
# endif
#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");
	}
}

static DEFINE_SPINLOCK(die_lock);

void die(const char * str, struct pt_regs * regs, long err)
{
	static int die_counter;

	oops_enter();

	spin_lock_irq(&die_lock);
	console_verbose();
	bust_spinlocks(1);

	printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
	print_modules();
	show_regs(regs);

	printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
			task_pid_nr(current), 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));

	notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);

	bust_spinlocks(0);
	add_taint(TAINT_DIE);
	spin_unlock_irq(&die_lock);
	oops_exit();

	if (kexec_should_crash(current))
		crash_kexec(regs);

	if (in_interrupt())
		panic("Fatal exception in interrupt");

	if (panic_on_oops)
		panic("Fatal exception");

	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);
}

/*
 * 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
 */
static void 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;
		}

		die(str, regs, err);
	}
}

static inline void sign_extend(unsigned int count, unsigned char *dst)
{
#ifdef __LITTLE_ENDIAN__
	if ((count == 1) && dst[0] & 0x80) {
		dst[1] = 0xff;
		dst[2] = 0xff;
		dst[3] = 0xff;
	}
	if ((count == 2) && dst[1] & 0x80) {
		dst[2] = 0xff;
		dst[3] = 0xff;
	}
#else
	if ((count == 1) && dst[3] & 0x80) {
		dst[2] = 0xff;
		dst[1] = 0xff;
		dst[0] = 0xff;
	}
	if ((count == 2) && dst[2] & 0x80) {
		dst[1] = 0xff;
		dst[0] = 0xff;
	}
#endif
}

static struct mem_access