diff options
Diffstat (limited to 'arch/x86/kernel/nmi.c')
| -rw-r--r-- | arch/x86/kernel/nmi.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c new file mode 100644 index 00000000000..68d758aca8c --- /dev/null +++ b/arch/x86/kernel/nmi.c @@ -0,0 +1,178 @@ +/* + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs + * + * Pentium III FXSR, SSE support + * Gareth Hughes <gareth@valinux.com>, May 2000 + */ + +/* + * Handle hardware traps and faults. + */ +#include <linux/spinlock.h> +#include <linux/kprobes.h> +#include <linux/kdebug.h> +#include <linux/nmi.h> + +#if defined(CONFIG_EDAC) +#include <linux/edac.h> +#endif + +#include <linux/atomic.h> +#include <asm/traps.h> +#include <asm/mach_traps.h> + +static int ignore_nmis; + +int unknown_nmi_panic; +/* + * Prevent NMI reason port (0x61) being accessed simultaneously, can + * only be used in NMI handler. + */ +static DEFINE_RAW_SPINLOCK(nmi_reason_lock); + +static int __init setup_unknown_nmi_panic(char *str) +{ + unknown_nmi_panic = 1; + return 1; +} +__setup("unknown_nmi_panic", setup_unknown_nmi_panic); + +static notrace __kprobes void +pci_serr_error(unsigned char reason, struct pt_regs *regs) +{ + pr_emerg("NMI: PCI system error (SERR) for reason %02x on CPU %d.\n", + reason, smp_processor_id()); + + /* + * On some machines, PCI SERR line is used to report memory + * errors. EDAC makes use of it. + */ +#if defined(CONFIG_EDAC) + if (edac_handler_set()) { + edac_atomic_assert_error(); + return; + } +#endif + + if (panic_on_unrecovered_nmi) + panic("NMI: Not continuing"); + + pr_emerg("Dazed and confused, but trying to continue\n"); + + /* Clear and disable the PCI SERR error line. */ + reason = (reason & NMI_REASON_CLEAR_MASK) | NMI_REASON_CLEAR_SERR; + outb(reason, NMI_REASON_PORT); +} + +static notrace __kprobes void +io_check_error(unsigned char reason, struct pt_regs *regs) +{ + unsigned long i; + + pr_emerg( + "NMI: IOCK error (debug interrupt?) for reason %02x on CPU %d.\n", + reason, smp_processor_id()); + show_registers(regs); + + if (panic_on_io_nmi) + panic("NMI IOCK error: Not continuing"); + + /* Re-enable the IOCK line, wait for a few seconds */ + reason = (reason & NMI_REASON_CLEAR_MASK) | NMI_REASON_CLEAR_IOCHK; + outb(reason, NMI_REASON_PORT); + + i = 20000; + while (--i) { + touch_nmi_watchdog(); + udelay(100); + } + + reason &= ~NMI_REASON_CLEAR_IOCHK; + outb(reason, NMI_REASON_PORT); +} + +static notrace __kprobes void +unknown_nmi_error(unsigned char reason, struct pt_regs *regs) +{ + if (notify_die(DIE_NMIUNKNOWN, "nmi", regs, reason, 2, SIGINT) == + NOTIFY_STOP) + return; +#ifdef CONFIG_MCA + /* + * Might actually be able to figure out what the guilty party + * is: + */ + if (MCA_bus) { + mca_handle_nmi(); + return; + } +#endif + pr_emerg("Uhhuh. NMI received for unknown reason %02x on CPU %d.\n", + reason, smp_processor_id()); + + pr_emerg("Do you have a strange power saving mode enabled?\n"); + if (unknown_nmi_panic || panic_on_unrecovered_nmi) + panic("NMI: Not continuing"); + + pr_emerg("Dazed and confused, but trying to continue\n"); +} + +static notrace __kprobes void default_do_nmi(struct pt_regs *regs) +{ + unsigned char reason = 0; + + /* + * CPU-specific NMI must be processed before non-CPU-specific + * NMI, otherwise we may lose it, because the CPU-specific + * NMI can not be detected/processed on other CPUs. + */ + if (notify_die(DIE_NMI, "nmi", regs, 0, 2, SIGINT) == NOTIFY_STOP) + return; + + /* Non-CPU-specific NMI: NMI sources can be processed on any CPU */ + raw_spin_lock(&nmi_reason_lock); + reason = get_nmi_reason(); + + if (reason & NMI_REASON_MASK) { + if (reason & NMI_REASON_SERR) + pci_serr_error(reason, regs); + else if (reason & NMI_REASON_IOCHK) + io_check_error(reason, regs); +#ifdef CONFIG_X86_32 + /* + * Reassert NMI in case it became active + * meanwhile as it's edge-triggered: + */ + reassert_nmi(); +#endif + raw_spin_unlock(&nmi_reason_lock); + return; + } + raw_spin_unlock(&nmi_reason_lock); + + unknown_nmi_error(reason, regs); +} + +dotraplinkage notrace __kprobes void +do_nmi(struct pt_regs *regs, long error_code) +{ + nmi_enter(); + + inc_irq_stat(__nmi_count); + + if (!ignore_nmis) + default_do_nmi(regs); + + nmi_exit(); +} + +void stop_nmi(void) +{ + ignore_nmis++; +} + +void restart_nmi(void) +{ + ignore_nmis--; +} |