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/*
* 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 <asm/stacktrace.h>
#include <asm/processor.h>
#include <asm/debugreg.h>
#include <linux/atomic.h>
#include <asm/text-patching.h>
#include <asm/ftrace.h>
#include <asm/traps.h>
#include <asm/desc.h>
#include <asm/fpu/internal.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/trace/mpx.h>
#include <asm/mpx.h>
#include <asm/vm86.h>
#include <asm/umip.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>
#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();
}
/*
* In IST context, we explicitly disable preemption. This serves two
* purposes: it makes it much less likely that we would accidentally
* schedule in IST context and it will force a warning if we somehow
* manage to schedule by accident.
*/
void ist_enter(struct pt_regs *regs)
{
if (user_mode(regs)) {
RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
} else {
/*
* We might have interrupted pretty much anything. In
* fact, if we're a machine check, we can even interrupt
* NMI processing. We don't want in_nmi() to return true,
* but we need to notify RCU.
*/
rcu_nmi_enter();
}
preempt_disable();
/* This code is a bit fragile. Test it. */
RCU_LOCKDEP_WARN(!rcu_is_watching(), "ist_enter didn't work");
}
NOKPROBE_SYMBOL(ist_enter);
void ist_exit(struct pt_regs *regs)
{
preempt_enable_no_resched();
if (!user_mode(regs))
rcu_nmi_exit();
}
/**
* ist_begin_non_atomic() - begin a non-atomic section in an IST exception
* @regs: regs passed to the IST exception handler
*
* IST exception handlers normally cannot schedule. As a special
* exception, if the exception interrupted userspace code (i.e.
* user_mode(regs) would return true) and the exception was not
* a double fault, it can be safe to schedule. ist_begin_non_atomic()
* begins a non-atomic section within an ist_enter()/ist_exit() region.
* Callers are responsible for enabling interrupts themselves inside
* the non-atomic section, and callers must call ist_end_non_atomic()
* before ist_exit().
*/
void ist_begin_non_atomic(struct pt_regs *regs)
{
BUG_ON(!user_mode(regs));
/*
* Sanity check: we need to be on the normal thread stack. This
* will catch asm bugs and any attempt to use ist_preempt_enable
* from double_fault.
*/
BUG_ON(!on_thread_stack());
preempt_enable_no_resched();
}
/**
* ist_end_non_atomic() - begin a non-atomic section in an IST exception
*
* Ends a non-atomic section started with ist_begin_non_atomic().
*/
void ist_end_non_atomic(void)
{
preempt_disable();
}
int is_valid_bugaddr(unsigned long addr)
{
unsigned short ud;
if (addr < TASK_SIZE_MAX)
return 0;
if (probe_kernel_address((unsigned short *)addr, ud))
return 0;
return ud == INSN_UD0 || ud == INSN_UD2;
}
int fixup_bug(struct pt_regs *regs, int trapnr)
{
if (trapnr != X86_TRAP_UD)
return 0;
switch (report_bug(regs->ip, regs)) {
case BUG_TRAP_TYPE_NONE:
case BUG_TRAP_TYPE_BUG:
break;
case BUG_TRAP_TYPE_WARN:
regs->ip += LEN_UD2;
return 1;
}
return 0;
}
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);
}
/*
* 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 do_general_protection below.
*/
tsk->thread.error_code = error_code;
tsk->thread.trap_nr = trapnr;
return -1;
}
static void show_signal(struct task_struct *tsk, int signr,
const
|