diff options
| -rw-r--r-- | arch/x86/include/asm/nmi.h | 18 | ||||
| -rw-r--r-- | arch/x86/kernel/nmi.c | 153 |
2 files changed, 171 insertions, 0 deletions
diff --git a/arch/x86/include/asm/nmi.h b/arch/x86/include/asm/nmi.h index 4886a68f267..480b69b7575 100644 --- a/arch/x86/include/asm/nmi.h +++ b/arch/x86/include/asm/nmi.h @@ -42,6 +42,24 @@ void arch_trigger_all_cpu_backtrace(void); #define NMI_LOCAL_NORMAL_PRIOR (NMI_LOCAL_BIT | NMI_NORMAL_PRIOR) #define NMI_LOCAL_LOW_PRIOR (NMI_LOCAL_BIT | NMI_LOW_PRIOR) +#define NMI_FLAG_FIRST 1 + +enum { + NMI_LOCAL=0, + NMI_UNKNOWN, + NMI_MAX +}; + +#define NMI_DONE 0 +#define NMI_HANDLED 1 + +typedef int (*nmi_handler_t)(unsigned int, struct pt_regs *); + +int register_nmi_handler(unsigned int, nmi_handler_t, unsigned long, + const char *); + +void unregister_nmi_handler(unsigned int, const char *); + void stop_nmi(void); void restart_nmi(void); diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 68d758aca8c..327748d4f6b 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -13,6 +13,9 @@ #include <linux/kprobes.h> #include <linux/kdebug.h> #include <linux/nmi.h> +#include <linux/delay.h> +#include <linux/hardirq.h> +#include <linux/slab.h> #if defined(CONFIG_EDAC) #include <linux/edac.h> @@ -21,6 +24,33 @@ #include <linux/atomic.h> #include <asm/traps.h> #include <asm/mach_traps.h> +#include <asm/nmi.h> + +#define NMI_MAX_NAMELEN 16 +struct nmiaction { + struct list_head list; + nmi_handler_t handler; + unsigned int flags; + char *name; +}; + +struct nmi_desc { + spinlock_t lock; + struct list_head head; +}; + +static struct nmi_desc nmi_desc[NMI_MAX] = +{ + { + .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[0].lock), + .head = LIST_HEAD_INIT(nmi_desc[0].head), + }, + { + .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[1].lock), + .head = LIST_HEAD_INIT(nmi_desc[1].head), + }, + +}; static int ignore_nmis; @@ -38,6 +68,129 @@ static int __init setup_unknown_nmi_panic(char *str) } __setup("unknown_nmi_panic", setup_unknown_nmi_panic); +#define nmi_to_desc(type) (&nmi_desc[type]) + +static int notrace __kprobes nmi_handle(unsigned int type, struct pt_regs *regs) +{ + struct nmi_desc *desc = nmi_to_desc(type); + struct nmiaction *a; + int handled=0; + + rcu_read_lock(); + + /* + * NMIs are edge-triggered, which means if you have enough + * of them concurrently, you can lose some because only one + * can be latched at any given time. Walk the whole list + * to handle those situations. + */ + list_for_each_entry_rcu(a, &desc->head, list) { + + handled += a->handler(type, regs); + + } + + rcu_read_unlock(); + + /* return total number of NMI events handled */ + return handled; +} + +static int __setup_nmi(unsigned int type, struct nmiaction *action) +{ + struct nmi_desc *desc = nmi_to_desc(type); + unsigned long flags; + + spin_lock_irqsave(&desc->lock, flags); + + /* + * some handlers need to be executed first otherwise a fake + * event confuses some handlers (kdump uses this flag) + */ + if (action->flags & NMI_FLAG_FIRST) + list_add_rcu(&action->list, &desc->head); + else + list_add_tail_rcu(&action->list, &desc->head); + + spin_unlock_irqrestore(&desc->lock, flags); + return 0; +} + +static struct nmiaction *__free_nmi(unsigned int type, const char *name) +{ + struct nmi_desc *desc = nmi_to_desc(type); + struct nmiaction *n; + unsigned long flags; + + spin_lock_irqsave(&desc->lock, flags); + + list_for_each_entry_rcu(n, &desc->head, list) { + /* + * the name passed in to describe the nmi handler + * is used as the lookup key + */ + if (!strcmp(n->name, name)) { + WARN(in_nmi(), + "Trying to free NMI (%s) from NMI context!\n", n->name); + list_del_rcu(&n->list); + break; + } + } + + spin_unlock_irqrestore(&desc->lock, flags); + synchronize_rcu(); + return (n); +} + +int register_nmi_handler(unsigned int type, nmi_handler_t handler, + unsigned long nmiflags, const char *devname) +{ + struct nmiaction *action; + int retval = -ENOMEM; + + if (!handler) + return -EINVAL; + + action = kzalloc(sizeof(struct nmiaction), GFP_KERNEL); + if (!action) + goto fail_action; + + action->handler = handler; + action->flags = nmiflags; + action->name = kstrndup(devname, NMI_MAX_NAMELEN, GFP_KERNEL); + if (!action->name) + goto fail_action_name; + + retval = __setup_nmi(type, action); + + if (retval) + goto fail_setup_nmi; + + return retval; + +fail_setup_nmi: + kfree(action->name); +fail_action_name: + kfree(action); +fail_action: + + return retval; +} +EXPORT_SYMBOL_GPL(register_nmi_handler); + +void unregister_nmi_handler(unsigned int type, const char *name) +{ + struct nmiaction *a; + + a = __free_nmi(type, name); + if (a) { + kfree(a->name); + kfree(a); + } +} + +EXPORT_SYMBOL_GPL(unregister_nmi_handler); + static notrace __kprobes void pci_serr_error(unsigned char reason, struct pt_regs *regs) { |