linux/arch/x86/include/asm/mach_traps.h
Jacob Pan 064a59b6dd x86/mrst: Avoid reporting wrong nmi status
Moorestown/Medfield platform does not have port 0x61 to report
NMI status, nor does it have external NMI sources. The only NMI
sources are from lapic, as results of perf counter overflow or
IPI, e.g. NMI watchdog or spin lock debug.

Reading port 0x61 on Moorestown will return 0xff which misled
NMI handlers to false critical errors such memory parity error.
The subsequent ioport access for NMI handling can also cause
undefined behavior on Moorestown.

This patch allows kernel process NMI due to watchdog or backrace
dump without unnecessary hangs.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
[hand applied]
Signed-off-by: Alan Cox <alan@linux.intel.com>
2011-11-10 16:21:01 +01:00

44 lines
974 B
C

/*
* Machine specific NMI handling for generic.
* Split out from traps.c by Osamu Tomita <tomita@cinet.co.jp>
*/
#ifndef _ASM_X86_MACH_DEFAULT_MACH_TRAPS_H
#define _ASM_X86_MACH_DEFAULT_MACH_TRAPS_H
#include <asm/mc146818rtc.h>
#define NMI_REASON_PORT 0x61
#define NMI_REASON_SERR 0x80
#define NMI_REASON_IOCHK 0x40
#define NMI_REASON_MASK (NMI_REASON_SERR | NMI_REASON_IOCHK)
#define NMI_REASON_CLEAR_SERR 0x04
#define NMI_REASON_CLEAR_IOCHK 0x08
#define NMI_REASON_CLEAR_MASK 0x0f
static inline unsigned char default_get_nmi_reason(void)
{
return inb(NMI_REASON_PORT);
}
static inline void reassert_nmi(void)
{
int old_reg = -1;
if (do_i_have_lock_cmos())
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 */
if (old_reg >= 0)
outb(old_reg, 0x70);
else
unlock_cmos();
}
#endif /* _ASM_X86_MACH_DEFAULT_MACH_TRAPS_H */