/*
* 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--;
}
