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Diffstat (limited to 'arch/x86/kernel/nmi.c')
-rw-r--r--arch/x86/kernel/nmi.c75
1 files changed, 15 insertions, 60 deletions
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index bdcc5146de96..2de365f15684 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -303,7 +303,7 @@ NOKPROBE_SYMBOL(unknown_nmi_error);
static DEFINE_PER_CPU(bool, swallow_nmi);
static DEFINE_PER_CPU(unsigned long, last_nmi_rip);
-static void default_do_nmi(struct pt_regs *regs)
+static noinstr void default_do_nmi(struct pt_regs *regs)
{
unsigned char reason = 0;
int handled;
@@ -329,6 +329,9 @@ static void default_do_nmi(struct pt_regs *regs)
__this_cpu_write(last_nmi_rip, regs->ip);
+ instrumentation_begin();
+ trace_hardirqs_off_finish();
+
handled = nmi_handle(NMI_LOCAL, regs);
__this_cpu_add(nmi_stats.normal, handled);
if (handled) {
@@ -342,7 +345,7 @@ static void default_do_nmi(struct pt_regs *regs)
*/
if (handled > 1)
__this_cpu_write(swallow_nmi, true);
- return;
+ goto out;
}
/*
@@ -374,7 +377,7 @@ static void default_do_nmi(struct pt_regs *regs)
#endif
__this_cpu_add(nmi_stats.external, 1);
raw_spin_unlock(&nmi_reason_lock);
- return;
+ goto out;
}
raw_spin_unlock(&nmi_reason_lock);
@@ -412,8 +415,12 @@ static void default_do_nmi(struct pt_regs *regs)
__this_cpu_add(nmi_stats.swallow, 1);
else
unknown_nmi_error(reason, regs);
+
+out:
+ if (regs->flags & X86_EFLAGS_IF)
+ trace_hardirqs_on_prepare();
+ instrumentation_end();
}
-NOKPROBE_SYMBOL(default_do_nmi);
/*
* NMIs can page fault or hit breakpoints which will cause it to lose
@@ -467,44 +474,9 @@ enum nmi_states {
};
static DEFINE_PER_CPU(enum nmi_states, nmi_state);
static DEFINE_PER_CPU(unsigned long, nmi_cr2);
+static DEFINE_PER_CPU(unsigned long, nmi_dr7);
-#ifdef CONFIG_X86_64
-/*
- * In x86_64, we need to handle breakpoint -> NMI -> breakpoint. Without
- * some care, the inner breakpoint will clobber the outer breakpoint's
- * stack.
- *
- * If a breakpoint is being processed, and the debug stack is being
- * used, if an NMI comes in and also hits a breakpoint, the stack
- * pointer will be set to the same fixed address as the breakpoint that
- * was interrupted, causing that stack to be corrupted. To handle this
- * case, check if the stack that was interrupted is the debug stack, and
- * if so, change the IDT so that new breakpoints will use the current
- * stack and not switch to the fixed address. On return of the NMI,
- * switch back to the original IDT.
- */
-static DEFINE_PER_CPU(int, update_debug_stack);
-
-static bool notrace is_debug_stack(unsigned long addr)
-{
- struct cea_exception_stacks *cs = __this_cpu_read(cea_exception_stacks);
- unsigned long top = CEA_ESTACK_TOP(cs, DB);
- unsigned long bot = CEA_ESTACK_BOT(cs, DB1);
-
- if (__this_cpu_read(debug_stack_usage))
- return true;
- /*
- * Note, this covers the guard page between DB and DB1 as well to
- * avoid two checks. But by all means @addr can never point into
- * the guard page.
- */
- return addr >= bot && addr < top;
-}
-NOKPROBE_SYMBOL(is_debug_stack);
-#endif
-
-dotraplinkage notrace void
-do_nmi(struct pt_regs *regs, long error_code)
+DEFINE_IDTENTRY_RAW(exc_nmi)
{
if (IS_ENABLED(CONFIG_SMP) && cpu_is_offline(smp_processor_id()))
return;
@@ -517,18 +489,7 @@ do_nmi(struct pt_regs *regs, long error_code)
this_cpu_write(nmi_cr2, read_cr2());
nmi_restart:
-#ifdef CONFIG_X86_64
- /*
- * If we interrupted a breakpoint, it is possible that
- * the nmi handler will have breakpoints too. We need to
- * change the IDT such that breakpoints that happen here
- * continue to use the NMI stack.
- */
- if (unlikely(is_debug_stack(regs->sp))) {
- debug_stack_set_zero();
- this_cpu_write(update_debug_stack, 1);
- }
-#endif
+ this_cpu_write(nmi_dr7, local_db_save());
nmi_enter();
@@ -539,12 +500,7 @@ nmi_restart:
nmi_exit();
-#ifdef CONFIG_X86_64
- if (unlikely(this_cpu_read(update_debug_stack))) {
- debug_stack_reset();
- this_cpu_write(update_debug_stack, 0);
- }
-#endif
+ local_db_restore(this_cpu_read(nmi_dr7));
if (unlikely(this_cpu_read(nmi_cr2) != read_cr2()))
write_cr2(this_cpu_read(nmi_cr2));
@@ -554,7 +510,6 @@ nmi_restart:
if (user_mode(regs))
mds_user_clear_cpu_buffers();
}
-NOKPROBE_SYMBOL(do_nmi);
void stop_nmi(void)
{