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linux-next/arch/x86/include/asm/nmi.h
Li Zhong 72b3fb2471 x86/nmi: Fix page faults by nmiaction if kmemcheck is enabled
This patch tries to fix the problem of page fault exception
caused by accessing nmiaction structure in nmi if kmemcheck
is enabled.

If kmemcheck is enabled, the memory allocated through slab are
in pages that are marked non-present, so that some checks could
be done in the page fault handling code ( e.g. whether the
memory is read before written to ).

As nmiaction is allocated in this way, so it resides in a
non-present page. Then there is a page fault while the nmi code
accessing the nmiaction structure, which would then cause a
warning by WARN_ON_ONCE(in_nmi()) in kmemcheck_fault(), called
by do_page_fault().

This significantly simplifies the code as well, as the whole
dynamic allocation dance goes away.

v2: as Peter suggested, changed the nmiaction to use static
    storage.

v3: as Peter suggested, use macro to shorten the codes. Also
    keep the original usage of register_nmi_handler, so users of
    this call doesn't need change.

Tested-by: Seiji Aguchi <seiji.aguchi@hds.com>
Fixes: https://lkml.org/lkml/2012/3/2/356
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
[ simplified the wrappers ]
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: thomas.mingarelli@hp.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1333051877-15755-4-git-send-email-dzickus@redhat.com
[ tidied the patch a bit ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-04-25 12:44:06 +02:00

66 lines
1.4 KiB
C

#ifndef _ASM_X86_NMI_H
#define _ASM_X86_NMI_H
#include <linux/pm.h>
#include <asm/irq.h>
#include <asm/io.h>
#ifdef CONFIG_X86_LOCAL_APIC
extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);
extern int reserve_perfctr_nmi(unsigned int);
extern void release_perfctr_nmi(unsigned int);
extern int reserve_evntsel_nmi(unsigned int);
extern void release_evntsel_nmi(unsigned int);
struct ctl_table;
extern int proc_nmi_enabled(struct ctl_table *, int ,
void __user *, size_t *, loff_t *);
extern int unknown_nmi_panic;
void arch_trigger_all_cpu_backtrace(void);
#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
#endif
#define NMI_FLAG_FIRST 1
enum {
NMI_LOCAL=0,
NMI_UNKNOWN,
NMI_SERR,
NMI_IO_CHECK,
NMI_MAX
};
#define NMI_DONE 0
#define NMI_HANDLED 1
typedef int (*nmi_handler_t)(unsigned int, struct pt_regs *);
struct nmiaction {
struct list_head list;
nmi_handler_t handler;
unsigned int flags;
const char *name;
};
#define register_nmi_handler(t, fn, fg, n) \
({ \
static struct nmiaction fn##_na = { \
.handler = (fn), \
.name = (n), \
.flags = (fg), \
}; \
__register_nmi_handler((t), &fn##_na); \
})
int __register_nmi_handler(unsigned int, struct nmiaction *);
void unregister_nmi_handler(unsigned int, const char *);
void stop_nmi(void);
void restart_nmi(void);
void local_touch_nmi(void);
#endif /* _ASM_X86_NMI_H */