traps.c

linux-2.6.15.6

/*
 *  linux/arch/i386/traps.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Pentium III FXSR, SSE support
 *	Gareth Hughes <[e-mail]>, May 2000
 */

/*
 * 'Traps.c' handles hardware traps and faults after we have saved some
 * state in 'asm.s'.
 */
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/highmem.h>
#include <linux/kallsyms.h>
#include <linux/ptrace.h>
#include <linux/utsname.h>
#include <linux/kprobes.h>
#include <linux/kexec.h>

#ifdef CONFIG_EISA
#include <linux/ioport.h>
#include <linux/eisa.h>
#endif

#ifdef CONFIG_MCA
#include <linux/mca.h>
#endif

#include <asm/processor.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/atomic.h>
#include <asm/debugreg.h>
#include <asm/desc.h>
#include <asm/i387.h>
#include <asm/nmi.h>

#include <asm/smp.h>
#include <asm/arch_hooks.h>
#include <asm/kdebug.h>

#include <linux/module.h>

#include "mach_traps.h"

asmlinkage int system_call(void);

struct desc_struct default_ldt[] = { { 0, 0 }, { 0, 0 }, { 0, 0 },
		{ 0, 0 }, { 0, 0 } };

/* Do we ignore FPU interrupts ? */
char ignore_fpu_irq = 0;

/*
 * The IDT has to be page-aligned to simplify the Pentium
 * F0 0F bug workaround.. We have a special link segment
 * for this.
 */
struct desc_struct idt_table[256] __attribute__((__section__(".data.idt"))) = { {0, 0}, };

asmlinkage void divide_error(void);
asmlinkage void debug(void);
asmlinkage void nmi(void);
asmlinkage void int3(void);
asmlinkage void overflow(void);
asmlinkage void bounds(void);
asmlinkage void invalid_op(void);
asmlinkage void device_not_available(void);
asmlinkage void coprocessor_segment_overrun(void);
asmlinkage void invalid_TSS(void);
asmlinkage void segment_not_present(void);
asmlinkage void stack_segment(void);
asmlinkage void general_protection(void);
asmlinkage void page_fault(void);
asmlinkage void coprocessor_error(void);
asmlinkage void simd_coprocessor_error(void);
asmlinkage void alignment_check(void);
asmlinkage void spurious_interrupt_bug(void);
asmlinkage void machine_check(void);

static int kstack_depth_to_print = 24;
struct notifier_block *i386die_chain;
static DEFINE_SPINLOCK(die_notifier_lock);

int register_die_notifier(struct notifier_block *nb)
{
	int err = 0;
	unsigned long flags;
	spin_lock_irqsave(&die_notifier_lock, flags);
	err = notifier_chain_register(&i386die_chain, nb);
	spin_unlock_irqrestore(&die_notifier_lock, flags);
	return err;
}
EXPORT_SYMBOL(register_die_notifier);

static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
{
	return	p > (void *)tinfo &&
		p < (void *)tinfo + THREAD_SIZE - 3;
}

static inline unsigned long print_context_stack(struct thread_info *tinfo,
				unsigned long *stack, unsigned long ebp)
{
	unsigned long addr;

#ifdef	CONFIG_FRAME_POINTER
	while (valid_stack_ptr(tinfo, (void *)ebp)) {
		addr = *(unsigned long *)(ebp + 4);
		printk(" [<%08lx>] ", addr);
		print_symbol("%s", addr);
		printk("\n");
		ebp = *(unsigned long *)ebp;
	}
#else
	while (valid_stack_ptr(tinfo, stack)) {
		addr = *stack++;
		if (__kernel_text_address(addr)) {
			printk(" [<%08lx>]", addr);
			print_symbol(" %s", addr);
			printk("\n");
		}
	}
#endif
	return ebp;
}

void show_trace(struct task_struct *task, unsigned long * stack)
{
	unsigned long ebp;

	if (!task)
		task = current;

	if (task == current) {
		/* Grab ebp right from our regs */
		asm ("movl %%ebp, %0" : "=r" (ebp) : );
	} else {
		/* ebp is the last reg pushed by switch_to */
		ebp = *(unsigned long *) task->thread.esp;
	}

	while (1) {
		struct thread_info *context;
		context = (struct thread_info *)
			((unsigned long)stack & (~(THREAD_SIZE - 1)));
		ebp = print_context_stack(context, stack, ebp);
		stack = (unsigned long*)context->previous_esp;
		if (!stack)
			break;
		printk(" =======================\n");
	}
}

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

	if (esp == NULL) {
		if (task)
			esp = (unsigned long*)task->thread.esp;
		else
			esp = (unsigned long *)&esp;
	}

	stack = esp;
	for(i = 0; i < kstack_depth_to_print; i++) {
		if (kstack_end(stack))
			break;
		if (i && ((i % 8) == 0))
			printk("\n       ");
		printk("%08lx ", *stack++);
	}
	printk("\nCall Trace:\n");
	show_trace(task, esp);
}

/*
 * The architecture-independent dump_stack generator
 */
void dump_stack(void)
{
	unsigned long stack;

	show_trace(current, &stack);
}

EXPORT_SYMBOL(dump_stack);

void show_registers(struct pt_regs *regs)
{
	int i;
	int in_kernel = 1;
	unsigned long esp;
	unsigned short ss;

	esp = (unsigned long) (&regs->esp);
	savesegment(ss, ss);
	if (user_mode(regs)) {
		in_kernel = 0;
		esp = regs->esp;
		ss = regs->xss & 0xffff;
	}
	print_modules();
	printk("CPU:    %d\nEIP:    %04x:[<%08lx>]    %s VLI\nEFLAGS: %08lx"
			"   (%s) \n",
		smp_processor_id(), 0xffff & regs->xcs, regs->eip,
		print_tainted(), regs->eflags, system_utsname.release);
	print_symbol("EIP is at %s\n", regs->eip);
	printk("eax: %08lx   ebx: %08lx   ecx: %08lx   edx: %08lx\n",
		regs->eax, regs->ebx, regs->ecx, regs->edx);
	printk("esi: %08lx   edi: %08lx   ebp: %08lx   esp: %08lx\n",
		regs->esi, regs->edi, regs->ebp, esp);
	printk("ds: %04x   es: %04x   ss: %04x\n",
		regs->xds & 0xffff, regs->xes & 0xffff, ss);
	printk("Process %s (pid: %d, threadinfo=%p task=%p)",
		current->comm, current->pid, current_thread_info(), current);
	/*
	 * When in-kernel, we also print out the stack and code at the
	 * time of the fault..
	 */
	if (in_kernel) {
		u8 __user *eip;

		printk("\nStack: ");
		show_stack(NULL, (unsigned long*)esp);

		printk("Code: ");

		eip = (u8 __user *)regs->eip - 43;
		for (i = 0; i < 64; i++, eip++) {
			unsigned char c;

			if (eip < (u8 __user *)PAGE_OFFSET || __get_user(c, eip)) {
				printk(" Bad EIP value.");
				break;
			}
			if (eip == (u8 __user *)regs->eip)
				printk("<%02x> ", c);
			else
				printk("%02x ", c);
		}
	}
	printk("\n");
}	

static void handle_BUG(struct pt_regs *regs)
{
	unsigned short ud2;
	unsigned short line;
	char *file;
	char c;
	unsigned long eip;

	eip = regs->eip;

	if (eip < PAGE_OFFSET)
		goto no_bug;
	if (__get_user(ud2, (unsigned short __user *)eip))
		goto no_bug;
	if (ud2 != 0x0b0f)
		goto no_bug;
	if (__get_user(line, (unsigned short __user *)(eip + 2)))
		goto bug;
	if (__get_user(file, (char * __user *)(eip + 4)) ||
		(unsigned long)file < PAGE_OFFSET || __get_user(c, file))
		file = "<bad filename>";

	printk("------------[ cut here ]------------\n");
	printk(KERN_ALERT "kernel BUG at %s:%d!\n", file, line);

no_bug:
	return;

	/* Here we know it was a BUG but file-n-line is unavailable */
bug:
	printk("Kernel BUG\n");
}

/* This is gone through when something in the kernel
 * has done something bad and is about to be terminated.
*/
void die(const char * str, struct pt_regs * regs, long err)
{
	static struct {
		spinlock_t lock;
		u32 lock_owner;
		int lock_owner_depth;
	} die = {
		.lock =			SPIN_LOCK_UNLOCKED,
		.lock_owner =		-1,
		.lock_owner_depth =	0
	};
	static int die_counter;

	if (die.lock_owner != raw_smp_processor_id()) {
		console_verbose();
		spin_lock_irq(&die.lock);
		die.lock_owner = smp_processor_id();
		die.lock_owner_depth = 0;
		bust_spinlocks(1);
	}

	if (++die.lock_owner_depth < 3) {
		int nl = 0;
		handle_BUG(regs);
		printk(KERN_ALERT "%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
#ifdef CONFIG_PREEMPT
		printk("PREEMPT ");
		nl = 1;
#endif
#ifdef CONFIG_SMP
		printk("SMP ");
		nl = 1;
#endif
#ifdef CONFIG_DEBUG_PAGEALLOC
		printk("DEBUG_PAGEALLOC");
		nl = 1;
#endif
		if (nl)
			printk("\n");
	notify_die(DIE_OOPS, (char *)str, regs, err, 255, SIGSEGV);
		show_registers(regs);
  	} else
		printk(KERN_ERR "Recursive die() failure, output suppressed\n");

	bust_spinlocks(0);
	die.lock_owner = -1;
	spin_unlock_irq(&die.lock);

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

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

	if (panic_on_oops) {
		printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
		ssleep(5);
		panic("Fatal exception");
	}
	do_exit(SIGSEGV);
}

static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
{
	if (!user_mode_vm(regs))
		die(str, regs, err);
}

static void __kprobes do_trap(int trapnr, int signr, char *str, int vm86,
			      struct pt_regs * regs, long error_code,
			      siginfo_t *info)
{
	struct task_struct *tsk = current;
	tsk->thread.error_code = error_code;
	tsk->thread.trap_no = trapnr;

	if (regs->eflags & VM_MASK) {
		if (vm86)
			goto vm86_trap;
		goto trap_signal;
	}

	if (!user_mode(regs))
		goto kernel_trap;

	trap_signal: {
		if (info)
			force_sig_info(signr, info, tsk);
		else
			force_sig(signr, tsk);
		return;
	}

	kernel_trap: {
		if (!fixup_exception(regs))
			die(str, regs, error_code);
		return;
	}

	vm86_trap: {
		int ret = handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr);
		if (ret) goto trap_signal;
		return;
	}
}

#define DO_ERROR(trapnr, signr, str, name) \
fastcall void do_##name(struct pt_regs * regs, long error_code) \
{ \
	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
						== NOTIFY_STOP) \
		return; \
	do_trap(trapnr, signr, str, 0, regs, error_code, NULL); \
}

#define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
fastcall void do_##name(struct pt_regs * regs, long error_code) \
{ \
	siginfo_t info; \
	info.si_signo = signr; \
	info.si_errno = 0; \
	info.si_code = sicode; \
	info.si_addr = (void __user *)siaddr; \
	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
						== NOTIFY_STOP) \
		return; \
	do_trap(trapnr, signr, str, 0, regs, error_code, &info); \
}

#define DO_VM86_ERROR(trapnr, signr, str, name) \
fastcall void do_##name(struct pt_regs * regs, long error_code) \
{ \
	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
						== NOTIFY_STOP) \
		return; \
	do_trap(trapnr, signr, str, 1, regs, error_code, NULL); \
}

#define DO_VM86_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
fastcall void do_##name(struct pt_regs * regs, long error_code) \
{ \
	siginfo_t info; \
	info.si_signo = signr; \
	info.si_errno = 0; \
	info.si_code = sicode; \
	info.si_addr = (void __user *)siaddr; \
	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
						== NOTIFY_STOP) \
		return; \
	do_trap(trapnr, signr, str, 1, regs, error_code, &info); \
}

DO_VM86_ERROR_INFO( 0, SIGFPE,  "divide error", divide_error, FPE_INTDIV, regs->eip)
#ifndef CONFIG_KPROBES
DO_VM86_ERROR( 3, SIGTRAP, "int3", int3)
#endif
DO_VM86_ERROR( 4, SIGSEGV, "overflow", overflow)
DO_VM86_ERROR( 5, SIGSEGV, "bounds", bounds)
DO_ERROR_INFO( 6, SIGILL,  "invalid operand", invalid_op, ILL_ILLOPN, regs->eip)
DO_ERROR( 9, SIGFPE,  "coprocessor segment overrun", coprocessor_segment_overrun)
DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
DO_ERROR(11, SIGBUS,  "segment not present", segment_not_present)
DO_ERROR(12, SIGBUS,  "stack segment", stack_segment)
DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0)

fastcall void __kprobes do_general_protection(struct pt_regs * regs,
					      long error_code)
{
	int cpu = get_cpu();
	struct tss_struct *tss = &per_cpu(init_tss, cpu);
	struct thread_struct *thread = &current->thread;

	/*
	 * Perform the lazy TSS's I/O bitmap copy. If the TSS has an
	 * invalid offset set (the LAZY one) and the faulting thread has
	 * a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS
	 * and we set the offset field correctly. Then we let the CPU to
	 * restart the faulting instruction.
	 */
	if (tss->io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY &&
	    thread->io_bitmap_ptr) {
		memcpy(tss->io_bitmap, thread->io_bitmap_ptr,
		       thread->io_bitmap_max);
		/*
		 * If the previously set map was extending to higher ports
		 * than the current one, pad extra space with 0xff (no access).
		 */
		if (thread->io_bitmap_max < tss->io_bitmap_max)
			memset((char *) tss->io_bitmap +
				thread->io_bitmap_max, 0xff,
				tss->io_bitmap_max - thread->io_bitmap_max);
		tss->io_bitmap_max = thread->io_bitmap_max;
		tss->io_bitmap_base = IO_BITMAP_OFFSET;
		tss->io_bitmap_owner = thread;
		put_cpu();
		return;
	}
	put_cpu();

	current->thread.error_code = error_code;
	current->thread.trap_no = 13;

	if (regs->eflags & VM_MASK)
		goto gp_in_vm86;

	if (!user_mode(regs))
		goto gp_in_kernel;

	current->thread.error_code = error_code;
	current->thread.trap_no = 13;
	force_sig(SIGSEGV, current);
	return;

gp_in_vm86:
	local_irq_enable();
	handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
	return;

gp_in_kernel:
	if (!fixup_exception(regs)) {
		if (notify_die(DIE_GPF, "general protection fault", regs,
				error_code, 13, SIGSEGV) == NOTIFY_STOP)
			return;
		die("general protection fault", regs, error_code);
	}
}

static void mem_parity_error(unsigned char reason, struct pt_regs * regs)
{
	printk("Uhhuh. NMI received. Dazed and confused, but trying to continue\n");
	printk("You probably have a hardware problem with your RAM chips\n");

	/* Clear and disable the memory parity error line. */
	clear_mem_error(reason);
}

static void io_check_error(unsigned char reason, struct pt_regs * regs)
{
	unsigned long i;

	printk("NMI: IOCK error (debug interrupt?)\n");
	show_registers(regs);

	/* Re-enable the IOCK line, wait for a few seconds */
	reason = (reason & 0xf) | 8;
	outb(reason, 0x61);
	i = 2000;
	while (--i) udelay(1000);
	reason &= ~8;
	outb(reason, 0x61);
}

static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
{
#ifdef CONFIG_MCA
	/* Might actually be able to figure out what the guilty party
	* is. */
	if( MCA_bus ) {
		mca_handle_nmi();
		return;