lockdep: fixup irq tracing

Ensure we fixup the IRQ state before we hit any locking code.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/kprobes_32.c

@@ -564,12 +564,7 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs)
 
 	resume_execution(cur, regs, kcb);
 	regs->eflags |= kcb->kprobe_saved_eflags;
-#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
-	if (raw_irqs_disabled_flags(regs->eflags))
-		trace_hardirqs_off();
-	else
-		trace_hardirqs_on();
-#endif
+	trace_hardirqs_fixup_flags(regs->eflags);
 
 	/*Restore back the original saved kprobes variables and continue. */
 	if (kcb->kprobe_status == KPROBE_REENTER) {

arch/x86/kernel/kprobes_64.c

@@ -551,12 +551,7 @@ int __kprobes post_kprobe_handler(struct pt_regs *regs)
 
 	resume_execution(cur, regs, kcb);
 	regs->eflags |= kcb->kprobe_saved_rflags;
-#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
-	if (raw_irqs_disabled_flags(regs->eflags))
-		trace_hardirqs_off();
-	else
-		trace_hardirqs_on();
-#endif
+	trace_hardirqs_fixup_flags(regs->eflags);
 
 	/* Restore the original saved kprobes variables and continue. */
 	if (kcb->kprobe_status == KPROBE_REENTER) {

arch/x86/kernel/traps_32.c

@@ -789,6 +789,8 @@ void restart_nmi(void)
 #ifdef CONFIG_KPROBES
 fastcall void __kprobes do_int3(struct pt_regs *regs, long error_code)
 {
+	trace_hardirqs_fixup();
+
 	if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
 			== NOTIFY_STOP)
 		return;

arch/x86/kernel/traps_64.c

@@ -807,6 +807,8 @@ asmlinkage __kprobes void default_do_nmi(struct pt_regs *regs)
 /* runs on IST stack. */
 asmlinkage void __kprobes do_int3(struct pt_regs * regs, long error_code)
 {
+	trace_hardirqs_fixup();
+
 	if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP) == NOTIFY_STOP) {
 		return;
 	}

arch/x86/mm/fault_32.c

@@ -303,6 +303,11 @@ fastcall void __kprobes do_page_fault(struct pt_regs *regs,
 	int write, si_code;
 	int fault;
 
+	/*
+	 * We can fault from pretty much anywhere, with unknown IRQ state.
+	 */
+	trace_hardirqs_fixup();
+
 	/* get the address */
         address = read_cr2();
 

arch/x86/mm/fault_64.c

@@ -304,6 +304,11 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	unsigned long flags;
 	siginfo_t info;
 
+	/*
+	 * We can fault from pretty much anywhere, with unknown IRQ state.
+	 */
+	trace_hardirqs_fixup();
+
 	tsk = current;
 	mm = tsk->mm;
 	prefetchw(&mm->mmap_sem);

include/asm-x86/irqflags_32.h

@@ -129,6 +129,27 @@ static inline int raw_irqs_disabled(void)
 
 	return raw_irqs_disabled_flags(flags);
 }
+
+/*
+ * makes the traced hardirq state match with the machine state
+ *
+ * should be a rarely used function, only in places where its
+ * otherwise impossible to know the irq state, like in traps.
+ */
+static inline void trace_hardirqs_fixup_flags(unsigned long flags)
+{
+	if (raw_irqs_disabled_flags(flags))
+		trace_hardirqs_off();
+	else
+		trace_hardirqs_on();
+}
+
+static inline void trace_hardirqs_fixup(void)
+{
+	unsigned long flags = __raw_local_save_flags();
+
+	trace_hardirqs_fixup_flags(flags);
+}
 #endif /* __ASSEMBLY__ */
 
 /*

include/asm-x86/irqflags_64.h

@@ -111,6 +111,26 @@ static inline int raw_irqs_disabled(void)
 	return raw_irqs_disabled_flags(flags);
 }
 
+/*
+ * makes the traced hardirq state match with the machine state
+ *
+ * should be a rarely used function, only in places where its
+ * otherwise impossible to know the irq state, like in traps.
+ */
+static inline void trace_hardirqs_fixup_flags(unsigned long flags)
+{
+	if (raw_irqs_disabled_flags(flags))
+		trace_hardirqs_off();
+	else
+		trace_hardirqs_on();
+}
+
+static inline void trace_hardirqs_fixup(void)
+{
+	unsigned long flags = __raw_local_save_flags();
+
+	trace_hardirqs_fixup_flags(flags);
+}
 /*
  * Used in the idle loop; sti takes one instruction cycle
  * to complete: