x86, NMI: Remove DIE_NMI_IPI

With priorities in place and no one really understanding the difference between
DIE_NMI and DIE_NMI_IPI, just remove DIE_NMI_IPI and convert everyone to DIE_NMI.

This also simplifies default_do_nmi() a little bit.  Instead of calling the
die_notifier in both the if and else part, just pull it out and call it before
the if-statement.  This has the side benefit of avoiding a call to the ioport
to see if there is an external NMI sitting around until after the (more frequent)
internal NMIs are dealt with.

Patch-Inspired-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1294348732-15030-5-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 8 insertions, 11 deletions

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index c7fd1cea0374..23f6ac05d04c 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -394,6 +394,14 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
         unsigned char reason = 0;
         int cpu;
 
+        /*
+         * CPU-specific NMI must be processed before non-CPU-specific
+         * NMI, otherwise we may lose it, because the CPU-specific
+         * NMI can not be detected/processed on other CPUs.
+         */
+        if (notify_die(DIE_NMI, "nmi", regs, 0, 2, SIGINT) == NOTIFY_STOP)
+                return;
+
         cpu = smp_processor_id();
 
         /* Only the BSP gets external NMIs from the system. */
@@ -401,21 +409,10 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
                 reason = get_nmi_reason();
 
         if (!(reason & NMI_REASON_MASK)) {
-                if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
-                                                                == NOTIFY_STOP)
-                        return;
-
-#ifdef CONFIG_X86_LOCAL_APIC
-                if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
-                                                        == NOTIFY_STOP)
-                        return;
-#endif
                 unknown_nmi_error(reason, regs);
 
                 return;
         }
-        if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
-                return;
 
         /* AK: following checks seem to be broken on modern chipsets. FIXME */
         if (reason & NMI_REASON_SERR)