path: root/arch/x86/kernel/traps.c

/*
 *  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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/context_tracking.h>
#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/export.h>
#include <linux/ptrace.h>
#include <linux/uprobes.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/kexec.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.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>
#include <linux/hardirq.h>
#include <linux/atomic.h>

#include <asm/stacktrace.h>
#include <asm/processor.h>
#include <asm/debugreg.h>
#include <asm/realmode.h>
#include <asm/text-patching.h>
#include <asm/ftrace.h>
#include <asm/traps.h>
#include <asm/desc.h>
#include <asm/fpu/api.h>
#include <asm/cpu.h>
#include <asm/cpu_entry_area.h>
#include <asm/mce.h>
#include <asm/fixmap.h>
#include <asm/mach_traps.h>
#include <asm/alternative.h>
#include <asm/fpu/xstate.h>
#include <asm/vm86.h>
#include <asm/umip.h>
#include <asm/insn.h>
#include <asm/insn-eval.h>
#include <asm/vdso.h>

#ifdef CONFIG_X86_64
#include <asm/x86_init.h>
#include <asm/proto.h>
#else
#include <asm/processor-flags.h>
#include <asm/setup.h>
#include <asm/proto.h>
#endif

DECLARE_BITMAP(system_vectors, NR_VECTORS);

static inline void cond_local_irq_enable(struct pt_regs *regs)
{
	if (regs->flags & X86_EFLAGS_IF)
		local_irq_enable();
}

static inline void cond_local_irq_disable(struct pt_regs *regs)
{
	if (regs->flags & X86_EFLAGS_IF)
		local_irq_disable();
}

__always_inline int is_valid_bugaddr(unsigned long addr)
{
	if (addr < TASK_SIZE_MAX)
		return 0;

	/*
	 * We got #UD, if the text isn't readable we'd have gotten
	 * a different exception.
	 */
	return *(unsigned short *)addr == INSN_UD2;
}

static nokprobe_inline int
do_trap_no_signal(struct task_struct *tsk, int trapnr, const char *str,
		  struct pt_regs *regs,	long error_code)
{
	if (v8086_mode(regs)) {
		/*
		 * Traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
		 * On nmi (interrupt 2), do_trap should not be called.
		 */
		if (trapnr < X86_TRAP_UD) {
			if (!handle_vm86_trap((struct kernel_vm86_regs *) regs,
						error_code, trapnr))
				return 0;
		}
	} else if (!user_mode(regs)) {
		if (fixup_exception(regs, trapnr, error_code, 0))
			return 0;

		tsk->thread.error_code = error_code;
		tsk->thread.trap_nr = trapnr;
		die(str, regs, error_code);
	} else {
		if (fixup_vdso_exception(regs, trapnr, error_code, 0))
			return 0;
	}

	/*
	 * We want error_code and trap_nr 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 exc_general_protection below.
	 */
	tsk->thread.error_code = error_code;
	tsk->thread.trap_nr = trapnr;

	return -1;
}

static void