From: Maxim Uvarov Date: Thu, 9 Aug 2012 15:14:24 +0000 (-0700) Subject: x86/nmi: Add new NMI queues to deal with IO_CHK and SERR X-Git-Tag: v2.6.39-400.9.0~424^2 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=c41ad91b6c205af786ca456fa5cf70f16b359636;p=users%2Fjedix%2Flinux-maple.git x86/nmi: Add new NMI queues to deal with IO_CHK and SERR In discussions with Thomas Mingarelli about hpwdt, he explained to me some issues they were some when using their virtual NMI button to test the hpwdt driver. It turns out the virtual NMI button used on HP's machines do no send unknown NMIs but instead send IO_CHK NMIs. The way the kernel code is written, the hpwdt driver can not register itself against that type of NMI and therefore can not successfully capture system information before panic'ing. To solve this I created two new NMI queues to allow driver to register against the IO_CHK and SERR NMIs. Or in the hpwdt all three (if you include unknown NMIs too). The change is straightforward and just mimics what the unknown NMI does. Reported-and-tested-by: Thomas Mingarelli Signed-off-by: Don Zickus Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/1333051877-15755-3-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar Conflicts: arch/x86/kernel/nmi.c drivers/watchdog/hpwdt.c --- diff --git a/arch/x86/include/asm/nmi.h b/arch/x86/include/asm/nmi.h index 480b69b75756..897fd775b629 100644 --- a/arch/x86/include/asm/nmi.h +++ b/arch/x86/include/asm/nmi.h @@ -47,6 +47,8 @@ void arch_trigger_all_cpu_backtrace(void); enum { NMI_LOCAL=0, NMI_UNKNOWN, + NMI_SERR, + NMI_IO_CHECK, NMI_MAX }; diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 3d795f077b15..fc9a4ea091fe 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -49,6 +49,14 @@ static struct nmi_desc nmi_desc[NMI_MAX] = .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[1].lock), .head = LIST_HEAD_INIT(nmi_desc[1].head), }, + { + .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[2].lock), + .head = LIST_HEAD_INIT(nmi_desc[2].head), + }, + { + .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[3].lock), + .head = LIST_HEAD_INIT(nmi_desc[3].head), + }, }; @@ -103,6 +111,15 @@ static int __setup_nmi(unsigned int type, struct nmiaction *action) spin_lock_irqsave(&desc->lock, flags); + /* + * most handlers of type NMI_UNKNOWN never return because + * they just assume the NMI is theirs. Just a sanity check + * to manage expectations + */ + WARN_ON_ONCE(type == NMI_UNKNOWN && !list_empty(&desc->head)); + WARN_ON_ONCE(type == NMI_SERR && !list_empty(&desc->head)); + WARN_ON_ONCE(type == NMI_IO_CHECK && !list_empty(&desc->head)); + /* * some handlers need to be executed first otherwise a fake * event confuses some handlers (kdump uses this flag) @@ -194,6 +211,10 @@ EXPORT_SYMBOL_GPL(unregister_nmi_handler); static notrace __kprobes void pci_serr_error(unsigned char reason, struct pt_regs *regs) { + /* check to see if anyone registered against these types of errors */ + if (nmi_handle(NMI_SERR, regs, false)) + return; + pr_emerg("NMI: PCI system error (SERR) for reason %02x on CPU %d.\n", reason, smp_processor_id()); @@ -223,6 +244,10 @@ io_check_error(unsigned char reason, struct pt_regs *regs) { unsigned long i; + /* check to see if anyone registered against these types of errors */ + if (nmi_handle(NMI_IO_CHECK, regs, false)) + return; + pr_emerg( "NMI: IOCK error (debug interrupt?) for reason %02x on CPU %d.\n", reason, smp_processor_id()); diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c index 57a848bc070e..40fece9f4afd 100644 --- a/drivers/watchdog/hpwdt.c +++ b/drivers/watchdog/hpwdt.c @@ -744,17 +744,15 @@ static int __devinit hpwdt_init_nmi_decoding(struct pci_dev *dev) * die notify list to handle a critical NMI. The default is to * be last so other users of the NMI signal can function. */ - if (priority) - die_notifier.priority = 0x7FFFFFFF; - - retval = register_die_notifier(&die_notifier); - if (retval != 0) { - dev_warn(&dev->dev, - "Unable to register a die notifier (err=%d).\n", - retval); - if (cru_rom_addr) - iounmap(cru_rom_addr); - } + retval = register_nmi_handler(NMI_UNKNOWN, hpwdt_pretimeout, 0, "hpwdt"); + if (retval) + goto error; + retval = register_nmi_handler(NMI_SERR, hpwdt_pretimeout, 0, "hpwdt"); + if (retval) + goto error1; + retval = register_nmi_handler(NMI_IO_CHECK, hpwdt_pretimeout, 0, "hpwdt"); + if (retval) + goto error2; dev_info(&dev->dev, "HP Watchdog Timer Driver: NMI decoding initialized" @@ -763,6 +761,18 @@ static int __devinit hpwdt_init_nmi_decoding(struct pci_dev *dev) (allow_kdump == 0) ? "OFF" : "ON", (priority == 0) ? "LAST" : "FIRST"); return 0; + +error2: + unregister_nmi_handler(NMI_SERR, "hpwdt"); +error1: + unregister_nmi_handler(NMI_UNKNOWN, "hpwdt"); +error: + dev_warn(&dev->dev, + "Unable to register a die notifier (err=%d).\n", + retval); + if (cru_rom_addr) + iounmap(cru_rom_addr); + return retval; } static void hpwdt_exit_nmi_decoding(void)