linux_dsm_epyc7002/arch/x86/include/asm/nmi.h
Changbin Du 248ed51048 x86/nmi: Remove irq_work from the long duration NMI handler
First, printk() is NMI-context safe now since the safe printk() has been
implemented and it already has an irq_work to make NMI-context safe.

Second, this NMI irq_work actually does not work if a NMI handler causes
panic by watchdog timeout. It has no chance to run in such case, while
the safe printk() will flush its per-cpu buffers before panicking.

While at it, repurpose the irq_work callback into a function which
concentrates the NMI duration checking and makes the code easier to
follow.

 [ bp: Massage. ]

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200111125427.15662-1-changbin.du@gmail.com
2020-01-11 15:55:39 +01:00

67 lines
1.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_NMI_H
#define _ASM_X86_NMI_H
#include <linux/irq_work.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;
#endif /* CONFIG_X86_LOCAL_APIC */
#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;
u64 max_duration;
unsigned long flags;
const char *name;
};
#define register_nmi_handler(t, fn, fg, n, init...) \
({ \
static struct nmiaction init 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 */