~ubuntu-branches/ubuntu/precise/linux-lowlatency/precise-proposed

/*

 *  Copyright (C) 1991, 1992  Linus Torvalds

 *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs

 *

 *  Pentium III FXSR, SSE support

 *	Gareth Hughes <gareth@valinux.com>, May 2000

 */

/*

 * Handle hardware traps and faults.

 */

#include <linux/interrupt.h>

#include <linux/kallsyms.h>

#include <linux/spinlock.h>

#include <linux/kprobes.h>

#include <linux/uaccess.h>

#include <linux/kdebug.h>

#include <linux/kgdb.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/ptrace.h>

#include <linux/string.h>

#include <linux/delay.h>

#include <linux/errno.h>

#include <linux/kexec.h>

#include <linux/sched.h>

#include <linux/timer.h>

#include <linux/init.h>

#include <linux/bug.h>

#include <linux/nmi.h>

#include <linux/mm.h>

#include <linux/smp.h>

#include <linux/io.h>

#ifdef CONFIG_EISA

#include <linux/ioport.h>

#include <linux/eisa.h>

#endif

#ifdef CONFIG_MCA

#include <linux/mca.h>

#endif

#if defined(CONFIG_EDAC)

#include <linux/edac.h>

#endif

#include <asm/kmemcheck.h>

#include <asm/stacktrace.h>

#include <asm/processor.h>

#include <asm/debugreg.h>

#include <linux/atomic.h>

#include <asm/system.h>

#include <asm/traps.h>

#include <asm/desc.h>

#include <asm/i387.h>

#include <asm/mce.h>

#include <asm/mach_traps.h>

#ifdef CONFIG_X86_64

#include <asm/x86_init.h>

#include <asm/pgalloc.h>

#include <asm/proto.h>

#else

#include <asm/processor-flags.h>

#include <asm/setup.h>

asmlinkage int system_call(void);

/* Do we ignore FPU interrupts ? */

char ignore_fpu_irq;

/*

 * The IDT has to be page-aligned to simplify the Pentium

 * F0 0F bug workaround.

 */

gate_desc idt_table[NR_VECTORS] __page_aligned_data = { { { { 0, 0 } } }, };

#endif

DECLARE_BITMAP(used_vectors, NR_VECTORS);

EXPORT_SYMBOL_GPL(used_vectors);

static inline void conditional_sti(struct pt_regs *regs)

{

	if (regs->flags & X86_EFLAGS_IF)

		local_irq_enable();

}

static inline void preempt_conditional_sti(struct pt_regs *regs)

{

	inc_preempt_count();

	if (regs->flags & X86_EFLAGS_IF)

		local_irq_enable();

}

static inline void conditional_cli(struct pt_regs *regs)

{

	if (regs->flags & X86_EFLAGS_IF)

		local_irq_disable();

}

static inline void preempt_conditional_cli(struct pt_regs *regs)

{

	if (regs->flags & X86_EFLAGS_IF)

		local_irq_disable();

	dec_preempt_count();

}

#ifdef CONFIG_X86_32

static inline int

__compare_user_cs_desc(const struct desc_struct *desc1,

	const struct desc_struct *desc2)

{

	return ((desc1->limit0 != desc2->limit0) ||

		(desc1->limit != desc2->limit) ||

		(desc1->base0 != desc2->base0) ||

		(desc1->base1 != desc2->base1) ||

		(desc1->base2 != desc2->base2));

}

/*

 * lazy-check for CS validity on exec-shield binaries:

 *

 * the original non-exec stack patch was written by

 * Solar Designer <solar at openwall.com>. Thanks!

 */

static int

check_lazy_exec_limit(int cpu, struct pt_regs *regs, long error_code)

{

	struct desc_struct *desc1, *desc2;

	struct vm_area_struct *vma;

	unsigned long limit;

	if (current->mm == NULL)

		return 0;

	limit = -1UL;

	if (current->mm->context.exec_limit != -1UL) {

		limit = PAGE_SIZE;

		spin_lock(&current->mm->page_table_lock);

		for (vma = current->mm->mmap; vma; vma = vma->vm_next)

			if ((vma->vm_flags & VM_EXEC) && (vma->vm_end > limit))

				limit = vma->vm_end;

		vma = get_gate_vma(current);

		if (vma && (vma->vm_flags & VM_EXEC) && (vma->vm_end > limit))

			limit = vma->vm_end;

		spin_unlock(&current->mm->page_table_lock);

		if (limit >= TASK_SIZE)

			limit = -1UL;

		current->mm->context.exec_limit = limit;

	}

	set_user_cs(&current->mm->context.user_cs, limit);

	desc1 = &current->mm->context.user_cs;

	desc2 = get_cpu_gdt_table(cpu) + GDT_ENTRY_DEFAULT_USER_CS;

	if (__compare_user_cs_desc(desc1, desc2)) {

		/*

		 * The CS was not in sync - reload it and retry the

		 * instruction. If the instruction still faults then

		 * we won't hit this branch next time around.

		 */

		if (print_fatal_signals >= 2) {

			printk(KERN_ERR "#GPF fixup (%ld[seg:%lx]) at %08lx, CPU#%d.\n",

				error_code, error_code/8, regs->ip,

				smp_processor_id());

			printk(KERN_ERR "exec_limit: %08lx, user_cs: %08x/%08x, CPU_cs: %08x/%08x.\n",

				current->mm->context.exec_limit,

				desc1->a, desc1->b, desc2->a, desc2->b);

		}

		load_user_cs_desc(cpu, current->mm);

		return 1;

	}

	return 0;

}

#endif

static void __kprobes

do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,

	long error_code, siginfo_t *info)

{

	struct task_struct *tsk = current;

#ifdef CONFIG_X86_32

	if (regs->flags & X86_VM_MASK) {

		/*

		 * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.

		 * On nmi (interrupt 2), do_trap should not be called.

		 */

		if (trapnr < 6)

			goto vm86_trap;

		goto trap_signal;

	}

#endif

	if (!user_mode(regs))

		goto kernel_trap;

#ifdef CONFIG_X86_32

trap_signal:

#endif

	/*

	 * We want error_code and trap_no set for userspace faults and

	 * kernelspace faults which result in die(), but not

	 * kernelspace faults which are fixed up.  die() gives the

	 * process no chance to handle the signal and notice the

	 * kernel fault information, so that won't result in polluting

	 * the information about previously queued, but not yet

	 * delivered, faults.  See also do_general_protection below.

	 */

	tsk->thread.error_code = error_code;

	tsk->thread.trap_no = trapnr;

#ifdef CONFIG_X86_64

	if (show_unhandled_signals && unhandled_signal(tsk, signr) &&

	    printk_ratelimit()) {

		printk(KERN_INFO

		       "%s[%d] trap %s ip:%lx sp:%lx error:%lx",

		       tsk->comm, tsk->pid, str,

		       regs->ip, regs->sp, error_code);

		print_vma_addr(" in ", regs->ip);

		printk("\n");

	}

#endif

	if (info)

		force_sig_info(signr, info, tsk);

	else

		force_sig(signr, tsk);

	return;

kernel_trap:

	if (!fixup_exception(regs)) {

		tsk->thread.error_code = error_code;

		tsk->thread.trap_no = trapnr;

		die(str, regs, error_code);

	}

	return;

#ifdef CONFIG_X86_32

vm86_trap:

	if (handle_vm86_trap((struct kernel_vm86_regs *) regs,

						error_code, trapnr))

		goto trap_signal;

	return;

#endif

}

#define DO_ERROR(trapnr, signr, str, name)				\

dotraplinkage void do_##name(struct pt_regs *regs, long error_code)	\

{									\

	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)	\

							== NOTIFY_STOP)	\

		return;							\

	conditional_sti(regs);						\

	do_trap(trapnr, signr, str, regs, error_code, NULL);		\

}

#define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr)		\

dotraplinkage 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;							\

	conditional_sti(regs);						\

	do_trap(trapnr, signr, str, regs, error_code, &info);		\

}

DO_ERROR_INFO(0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->ip)

DO_ERROR(4, SIGSEGV, "overflow", overflow)

DO_ERROR(5, SIGSEGV, "bounds", bounds)

DO_ERROR_INFO(6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip)

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)

#ifdef CONFIG_X86_32

DO_ERROR(12, SIGBUS, "stack segment", stack_segment)

#endif

DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)

#ifdef CONFIG_X86_64

/* Runs on IST stack */

dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)

{

	if (notify_die(DIE_TRAP, "stack segment", regs, error_code,

			12, SIGBUS) == NOTIFY_STOP)

		return;

	preempt_conditional_sti(regs);

	do_trap(12, SIGBUS, "stack segment", regs, error_code, NULL);

	preempt_conditional_cli(regs);

}

dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)

{

	static const char str[] = "double fault";

	struct task_struct *tsk = current;

	/* Return not checked because double check cannot be ignored */

	notify_die(DIE_TRAP, str, regs, error_code, 8, SIGSEGV);

	tsk->thread.error_code = error_code;

	tsk->thread.trap_no = 8;

	/*

	 * This is always a kernel trap and never fixable (and thus must

	 * never return).

	 */

	for (;;)

		die(str, regs, error_code);

}

#endif

dotraplinkage void __kprobes

do_general_protection(struct pt_regs *regs, long error_code)

{

	struct task_struct *tsk;

	conditional_sti(regs);

#ifdef CONFIG_X86_32

	if (regs->flags & X86_VM_MASK)

		goto gp_in_vm86;

#endif

	tsk = current;

	if (!user_mode(regs))

		goto gp_in_kernel;

#ifdef CONFIG_X86_32

{

	int cpu;

	int ok;

	cpu = get_cpu();

	ok = check_lazy_exec_limit(cpu, regs, error_code);

	put_cpu();

	if (ok)

		return;

	if (print_fatal_signals) {

		printk(KERN_ERR "#GPF(%ld[seg:%lx]) at %08lx, CPU#%d.\n",

			error_code, error_code/8, regs->ip, smp_processor_id());

		printk(KERN_ERR "exec_limit: %08lx, user_cs: %08x/%08x.\n",

			current->mm->context.exec_limit,

			current->mm->context.user_cs.a,

			current->mm->context.user_cs.b);

	}

}

#endif /*CONFIG_X86_32*/

	tsk->thread.error_code = error_code;

	tsk->thread.trap_no = 13;

	if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&

			printk_ratelimit()) {

		printk(KERN_INFO

			"%s[%d] general protection ip:%lx sp:%lx error:%lx",

			tsk->comm, task_pid_nr(tsk),

			regs->ip, regs->sp, error_code);

		print_vma_addr(" in ", regs->ip);

		printk("\n");

	}

	force_sig(SIGSEGV, tsk);

	return;

#ifdef CONFIG_X86_32

gp_in_vm86:

	local_irq_enable();

	handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);

	return;

#endif

gp_in_kernel:

	if (fixup_exception(regs))

		return;

	tsk->thread.error_code = error_code;

	tsk->thread.trap_no = 13;

	if (notify_die(DIE_GPF, "general protection fault", regs,

				error_code, 13, SIGSEGV) == NOTIFY_STOP)

		return;

	die("general protection fault", regs, error_code);

}

/* May run on IST stack. */

dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)

{

#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP

	if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)

			== NOTIFY_STOP)

		return;

#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */

#ifdef CONFIG_KPROBES

	if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)

			== NOTIFY_STOP)

		return;

#else

	if (notify_die(DIE_TRAP, "int3", regs, error_code, 3, SIGTRAP)

			== NOTIFY_STOP)

		return;

#endif

	preempt_conditional_sti(regs);

	do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);

	preempt_conditional_cli(regs);

}

#ifdef CONFIG_X86_64

/*

 * Help handler running on IST stack to switch back to user stack

 * for scheduling or signal handling. The actual stack switch is done in

 * entry.S

 */

asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)

{

	struct pt_regs *regs = eregs;

	/* Did already sync */

	if (eregs == (struct pt_regs *)eregs->sp)

		;

	/* Exception from user space */

	else if (user_mode(eregs))

		regs = task_pt_regs(current);

	/*

	 * Exception from kernel and interrupts are enabled. Move to

	 * kernel process stack.

	 */

	else if (eregs->flags & X86_EFLAGS_IF)

		regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));

	if (eregs != regs)

		*regs = *eregs;

	return regs;

}

#endif

/*

 * Our handling of the processor debug registers is non-trivial.

 * We do not clear them on entry and exit from the kernel. Therefore

 * it is possible to get a watchpoint trap here from inside the kernel.

 * However, the code in ./ptrace.c has ensured that the user can

 * only set watchpoints on userspace addresses. Therefore the in-kernel

 * watchpoint trap can only occur in code which is reading/writing

 * from user space. Such code must not hold kernel locks (since it

 * can equally take a page fault), therefore it is safe to call

 * force_sig_info even though that claims and releases locks.

 *

 * Code in ./signal.c ensures that the debug control register

 * is restored before we deliver any signal, and therefore that

 * user code runs with the correct debug control register even though

 * we clear it here.

 *

 * Being careful here means that we don't have to be as careful in a

 * lot of more complicated places (task switching can be a bit lazy

 * about restoring all the debug state, and ptrace doesn't have to

 * find every occurrence of the TF bit that could be saved away even

 * by user code)

 *

 * May run on IST stack.

 */

dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)

{

	struct task_struct *tsk = current;

	int user_icebp = 0;

	unsigned long dr6;

	int si_code;

	get_debugreg(dr6, 6);

	/* Filter out all the reserved bits which are preset to 1 */

	dr6 &= ~DR6_RESERVED;

	/*

	 * If dr6 has no reason to give us about the origin of this trap,

	 * then it's very likely the result of an icebp/int01 trap.

	 * User wants a sigtrap for that.

	 */

	if (!dr6 && user_mode(regs))

		user_icebp = 1;

	/* Catch kmemcheck conditions first of all! */

	if ((dr6 & DR_STEP) && kmemcheck_trap(regs))

		return;

	/* DR6 may or may not be cleared by the CPU */

	set_debugreg(0, 6);

	/*

	 * The processor cleared BTF, so don't mark that we need it set.

	 */

	clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP);

	/* Store the virtualized DR6 value */

	tsk->thread.debugreg6 = dr6;

	if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,

							SIGTRAP) == NOTIFY_STOP)

		return;

	/* It's safe to allow irq's after DR6 has been saved */

	preempt_conditional_sti(regs);

	if (regs->flags & X86_VM_MASK) {

		handle_vm86_trap((struct kernel_vm86_regs *) regs,

				error_code, 1);

		preempt_conditional_cli(regs);

		return;

	}

	/*

	 * Single-stepping through system calls: ignore any exceptions in

	 * kernel space, but re-enable TF when returning to user mode.

	 *

	 * We already checked v86 mode above, so we can check for kernel mode

	 * by just checking the CPL of CS.

	 */

	if ((dr6 & DR_STEP) && !user_mode(regs)) {

		tsk->thread.debugreg6 &= ~DR_STEP;

		set_tsk_thread_flag(tsk, TIF_SINGLESTEP);

		regs->flags &= ~X86_EFLAGS_TF;

	}

	si_code = get_si_code(tsk->thread.debugreg6);

	if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)

		send_sigtrap(tsk, regs, error_code, si_code);

	preempt_conditional_cli(regs);

	return;

}

/*

 * Note that we play around with the 'TS' bit in an attempt to get

 * the correct behaviour even in the presence of the asynchronous

 * IRQ13 behaviour

 */

void math_error(struct pt_regs *regs, int error_code, int trapnr)

{

	struct task_struct *task = current;

	siginfo_t info;

	unsigned short err;

	char *str = (trapnr == 16) ? "fpu exception" : "simd exception";

	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)

		return;

	conditional_sti(regs);

	if (!user_mode_vm(regs))

	{

		if (!fixup_exception(regs)) {

			task->thread.error_code = error_code;

			task->thread.trap_no = trapnr;

			die(str, regs, error_code);

		}

		return;

	}

	/*

	 * Save the info for the exception handler and clear the error.

	 */

	save_init_fpu(task);

	task->thread.trap_no = trapnr;

	task->thread.error_code = error_code;

	info.si_signo = SIGFPE;

	info.si_errno = 0;

	info.si_addr = (void __user *)regs->ip;

	if (trapnr == 16) {

		unsigned short cwd, swd;

		/*

		 * (~cwd & swd) will mask out exceptions that are not set to unmasked

		 * status.  0x3f is the exception bits in these regs, 0x200 is the

		 * C1 reg you need in case of a stack fault, 0x040 is the stack

		 * fault bit.  We should only be taking one exception at a time,

		 * so if this combination doesn't produce any single exception,

		 * then we have a bad program that isn't synchronizing its FPU usage

		 * and it will suffer the consequences since we won't be able to

		 * fully reproduce the context of the exception

		 */

		cwd = get_fpu_cwd(task);

		swd = get_fpu_swd(task);

		err = swd & ~cwd;

	} else {

		/*

		 * The SIMD FPU exceptions are handled a little differently, as there

		 * is only a single status/control register.  Thus, to determine which

		 * unmasked exception was caught we must mask the exception mask bits

		 * at 0x1f80, and then use these to mask the exception bits at 0x3f.

		 */

		unsigned short mxcsr = get_fpu_mxcsr(task);

		err = ~(mxcsr >> 7) & mxcsr;

	}

	if (err & 0x001) {	/* Invalid op */

		/*

		 * swd & 0x240 == 0x040: Stack Underflow

		 * swd & 0x240 == 0x240: Stack Overflow

		 * User must clear the SF bit (0x40) if set

		 */

		info.si_code = FPE_FLTINV;

	} else if (err & 0x004) { /* Divide by Zero */

		info.si_code = FPE_FLTDIV;

	} else if (err & 0x008) { /* Overflow */

		info.si_code = FPE_FLTOVF;

	} else if (err & 0x012) { /* Denormal, Underflow */

		info.si_code = FPE_FLTUND;

	} else if (err & 0x020) { /* Precision */

		info.si_code = FPE_FLTRES;

	} else {

		/*

		 * If we're using IRQ 13, or supposedly even some trap 16

		 * implementations, it's possible we get a spurious trap...

		 */

		return;		/* Spurious trap, no error */

	}

	force_sig_info(SIGFPE, &info, task);

}

dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)

{

#ifdef CONFIG_X86_32

	ignore_fpu_irq = 1;

#endif

	math_error(regs, error_code, 16);

}

dotraplinkage void

do_simd_coprocessor_error(struct pt_regs *regs, long error_code)

{

	math_error(regs, error_code, 19);

}

dotraplinkage void

do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)

{

	conditional_sti(regs);

#if 0

	/* No need to warn about this any longer. */

	printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n");

#endif

}

asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)

{

}

asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)

{

}

/*

 * This gets called with the process already owning the

 * FPU state, and with CR0.TS cleared. It just needs to

 * restore the FPU register state.

 */

void __math_state_restore(struct task_struct *tsk)

{

	/* We need a safe address that is cheap to find and that is already

	   in L1. We've just brought in "tsk->thread.has_fpu", so use that */

#define safe_address (tsk->thread.has_fpu)

	/* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception

	   is pending.  Clear the x87 state here by setting it to fixed

	   values. safe_address is a random variable that should be in L1 */

	alternative_input(

		ASM_NOP8 ASM_NOP2,

		"emms\n\t"	  	/* clear stack tags */

		"fildl %P[addr]",	/* set F?P to defined value */

		X86_FEATURE_FXSAVE_LEAK,

		[addr] "m" (safe_address));

	/*

	 * Paranoid restore. send a SIGSEGV if we fail to restore the state.

	 */

	if (unlikely(restore_fpu_checking(tsk))) {

		__thread_fpu_end(tsk);

		force_sig(SIGSEGV, tsk);

		return;

	}

}

/*

 * 'math_state_restore()' saves the current math information in the

 * old math state array, and gets the new ones from the current task

 *

 * Careful.. There are problems with IBM-designed IRQ13 behaviour.

 * Don't touch unless you *really* know how it works.

 *

 * Must be called with kernel preemption disabled (eg with local

 * local interrupts as in the case of do_device_not_available).

 */

void math_state_restore(void)

{

	struct task_struct *tsk = current;

	if (!tsk_used_math(tsk)) {

		local_irq_enable();

		/*

		 * does a slab alloc which can sleep

		 */

		if (init_fpu(tsk)) {

			/*

			 * ran out of memory!

			 */

			do_group_exit(SIGKILL);

			return;

		}

		local_irq_disable();

	}

	__thread_fpu_begin(tsk);

	__math_state_restore(tsk);

	tsk->fpu_counter++;

}

EXPORT_SYMBOL_GPL(math_state_restore);

dotraplinkage void __kprobes

do_device_not_available(struct pt_regs *regs, long error_code)

{

#ifdef CONFIG_MATH_EMULATION

	if (read_cr0() & X86_CR0_EM) {

		struct math_emu_info info = { };

		conditional_sti(regs);

		info.regs = regs;

		math_emulate(&info);

		return;

	}

#endif

	math_state_restore(); /* interrupts still off */

#ifdef CONFIG_X86_32

	conditional_sti(regs);

#endif

}

#ifdef CONFIG_X86_32

/*

 * The fixup code for errors in iret jumps to here (iret_exc). It loses

 * the original trap number and erorr code. The bogus trap 32 and error

 * code 0 are what the vanilla kernel delivers via:

 * DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0, 1)

 *

 * NOTE: Because of the final "1" in the macro we need to enable interrupts.

 *

 * In case of a general protection fault in the iret instruction, we

 * need to check for a lazy CS update for exec-shield.

 */

dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)

{

	int ok;

	int cpu;

	local_irq_enable();

	cpu = get_cpu();

	ok = check_lazy_exec_limit(cpu, regs, error_code);

	put_cpu();

	if (!ok && notify_die(DIE_TRAP, "iret exception", regs,

		error_code, 32, SIGSEGV) != NOTIFY_STOP) {

			siginfo_t info;

			info.si_signo = SIGSEGV;

			info.si_errno = 0;

			info.si_code = ILL_BADSTK;

			info.si_addr = 0;

			do_trap(32, SIGSEGV, "iret exception", regs, error_code, &info);

	}

}

#endif

/* Set of traps needed for early debugging. */

void __init early_trap_init(void)

{

	set_intr_gate_ist(1, &debug, DEBUG_STACK);

	/* int3 can be called from all */

	set_system_intr_gate_ist(3, &int3, DEBUG_STACK);

	set_intr_gate(14, &page_fault);

	load_idt(&idt_descr);

}

void __init trap_init(void)

{

	int i;

#ifdef CONFIG_EISA

	void __iomem *p = early_ioremap(0x0FFFD9, 4);

	if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))

		EISA_bus = 1;

	early_iounmap(p, 4);

#endif

	set_intr_gate(0, &divide_error);

	set_intr_gate_ist(2, &nmi, NMI_STACK);

	/* int4 can be called from all */

	set_system_intr_gate(4, &overflow);

	set_intr_gate(5, &bounds);

	set_intr_gate(6, &invalid_op);

	set_intr_gate(7, &device_not_available);

#ifdef CONFIG_X86_32

	set_task_gate(8, GDT_ENTRY_DOUBLEFAULT_TSS);

#else

	set_intr_gate_ist(8, &double_fault, DOUBLEFAULT_STACK);

#endif

	set_intr_gate(9, &coprocessor_segment_overrun);

	set_intr_gate(10, &invalid_TSS);

	set_intr_gate(11, &segment_not_present);

	set_intr_gate_ist(12, &stack_segment, STACKFAULT_STACK);

	set_intr_gate(13, &general_protection);

	set_intr_gate(15, &spurious_interrupt_bug);

	set_intr_gate(16, &coprocessor_error);