nmi.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _ASM_X86_NMI_H
  3#define _ASM_X86_NMI_H
  4
  5#include <linux/irq_work.h>
  6#include <linux/pm.h>
  7#include <asm/irq.h>
  8#include <asm/io.h>
  9
 10#ifdef CONFIG_X86_LOCAL_APIC
 11
 12extern int reserve_perfctr_nmi(unsigned int);
 13extern void release_perfctr_nmi(unsigned int);
 14extern int reserve_evntsel_nmi(unsigned int);
 15extern void release_evntsel_nmi(unsigned int);
 16
 17#endif /* CONFIG_X86_LOCAL_APIC */
 18
 19extern int unknown_nmi_panic;
 20extern int panic_on_unrecovered_nmi;
 21extern int panic_on_io_nmi;
 22
 23/* NMI handler flags */
 24#define NMI_FLAG_FIRST	1
 25
 26/**
 27 * enum - NMI types.
 28 * @NMI_LOCAL:    Local NMI, CPU-specific NMI generated by the Local APIC.
 29 * @NMI_UNKNOWN:  Unknown NMI, the source of the NMI may not be identified.
 30 * @NMI_SERR:     System Error NMI, typically triggered by PCI errors.
 31 * @NMI_IO_CHECK: I/O Check NMI, related to I/O errors.
 32 * @NMI_MAX:      Maximum value for NMI types.
 33 *
 34 * NMI types are used to categorize NMIs and to dispatch them to the
 35 * appropriate handler.
 36 */
 37enum {
 38	NMI_LOCAL=0,
 39	NMI_UNKNOWN,
 40	NMI_SERR,
 41	NMI_IO_CHECK,
 42	NMI_MAX
 43};
 44
 45/* NMI handler return values */
 46#define NMI_DONE	0
 47#define NMI_HANDLED	1
 48
 49typedef int (*nmi_handler_t)(unsigned int, struct pt_regs *);
 50
 51struct nmiaction {
 52	struct list_head	list;
 53	nmi_handler_t		handler;
 54	u64			max_duration;
 55	unsigned long		flags;
 56	const char		*name;
 57};
 58
 59/**
 60 * register_nmi_handler - Register a handler for a specific NMI type
 61 * @t:    NMI type (e.g. NMI_LOCAL)
 62 * @fn:   The NMI handler
 63 * @fg:   Flags associated with the NMI handler
 64 * @n:    Name of the NMI handler
 65 * @init: Optional __init* attributes for struct nmiaction
 66 *
 67 * Adds the provided handler to the list of handlers for the specified
 68 * NMI type. Handlers flagged with NMI_FLAG_FIRST would be executed first.
 69 *
 70 * Sometimes the source of an NMI can't be reliably determined which
 71 * results in an NMI being tagged as "unknown". Register an additional
 72 * handler using the NMI type - NMI_UNKNOWN to handle such cases. The
 73 * caller would get one last chance to assume responsibility for the
 74 * NMI.
 75 *
 76 * Return: 0 on success, or an error code on failure.
 77 */
 78#define register_nmi_handler(t, fn, fg, n, init...)	\
 79({							\
 80	static struct nmiaction init fn##_na = {	\
 81		.list = LIST_HEAD_INIT(fn##_na.list),	\
 82		.handler = (fn),			\
 83		.name = (n),				\
 84		.flags = (fg),				\
 85	};						\
 86	__register_nmi_handler((t), &fn##_na);		\
 87})
 88
 89int __register_nmi_handler(unsigned int, struct nmiaction *);
 90
 91/**
 92 * unregister_nmi_handler - Unregister a handler for a specific NMI type
 93 * @type: NMI type (e.g. NMI_LOCAL)
 94 * @name: Name of the NMI handler used during registration
 95 *
 96 * Removes the handler associated with the specified NMI type from the
 97 * NMI handler list. The "name" is used as a lookup key to identify the
 98 * handler.
 99 */
100void unregister_nmi_handler(unsigned int type, const char *name);
101
102void set_emergency_nmi_handler(unsigned int type, nmi_handler_t handler);
103
104void stop_nmi(void);
105void restart_nmi(void);
106void local_touch_nmi(void);
107
108#endif /* _ASM_X86_NMI_H */