[PATCH -tip 1/2 resend] x86, nmi: Define a name for NMI control port

Cyrill Gorcunov
2011-03-02T15:32:35Z

Also add a comment anout why we need in-out operations.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
---

Ingo I hope this time I've resolved MUA space injection.

arch/x86/include/asm/mach_traps.h | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)

Index: linux-2.6.git/arch/x86/include/asm/mach_traps.h
=====================================================================
--- linux-2.6.git.orig/arch/x86/include/asm/mach_traps.h
+++ linux-2.6.git/arch/x86/include/asm/mach_traps.h
@@ -8,6 +8,7 @@
#include <asm/mc146818rtc.h>

#define NMI_REASON_PORT 0x61
+#define NMI_ENABLE_PORT 0x70 /* Real-Time Clock Address Register as well */

#define NMI_REASON_SERR 0x80
#define NMI_REASON_IOCHK 0x40
@@ -30,12 +31,19 @@ static inline void reassert_nmi(void)
old_reg = current_lock_cmos_reg();
else
lock_cmos(0); /* register doesn't matter here */
- outb(0x8f, 0x70);
- inb(0x71); /* dummy */
- outb(0x0f, 0x70);
- inb(0x71); /* dummy */
+
+ /*
+ * This will cause the NMI output to transition low
+ * then high if there are any pending NMI sources. The
+ * CPU's NMI input logic will then register a new NMI.
+ */
+ outb(0x8f, NMI_ENABLE_PORT);
+ inb(0x71); /* dummy */
+ outb(0x0f, NMI_ENABLE_PORT);
+ inb(0x71); /* dummy */
+
if (old_reg >= 0)
- outb(old_reg, 0x70);
+ outb(old_reg, NMI_ENABLE_PORT);
else
unlock_cmos();
}

--
Cyrill