From 6f290b4e016d6c61511542cf6d9ebdef1965978e Mon Sep 17 00:00:00 2001 From: Aristeu Rozanski Date: Mon, 27 Oct 2008 12:42:34 -0400 Subject: x86, NMI watchdog: add support to enable and disable IOAPIC NMI Impact: change/improve the way /proc/sys/kernel/nmi_watchdog works This patch adds support to enable/disable IOAPIC NMI watchdog in runtime via procfs. Signed-off-by: Aristeu Rozanski Cc: "Maciej W. Rozycki" Signed-off-by: Ingo Molnar --- arch/x86/kernel/nmi.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'arch/x86/kernel/nmi.c') diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 2c97f07..2c005fa 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -340,6 +340,8 @@ void stop_apic_nmi_watchdog(void *unused) return; if (nmi_watchdog == NMI_LOCAL_APIC) lapic_watchdog_stop(); + else + __acpi_nmi_disable(NULL); __get_cpu_var(wd_enabled) = 0; atomic_dec(&nmi_active); } @@ -465,6 +467,24 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason) #ifdef CONFIG_SYSCTL +static void enable_ioapic_nmi_watchdog_single(void *unused) +{ + __get_cpu_var(wd_enabled) = 1; + atomic_inc(&nmi_active); + __acpi_nmi_enable(NULL); +} + +static void enable_ioapic_nmi_watchdog(void) +{ + on_each_cpu(enable_ioapic_nmi_watchdog_single, NULL, 1); + touch_nmi_watchdog(); +} + +static void disable_ioapic_nmi_watchdog(void) +{ + on_each_cpu(stop_apic_nmi_watchdog, NULL, 1); +} + static int __init setup_unknown_nmi_panic(char *str) { unknown_nmi_panic = 1; @@ -507,6 +527,11 @@ int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file, enable_lapic_nmi_watchdog(); else disable_lapic_nmi_watchdog(); + } else if (nmi_watchdog == NMI_IO_APIC) { + if (nmi_watchdog_enabled) + enable_ioapic_nmi_watchdog(); + else + disable_ioapic_nmi_watchdog(); } else { printk(KERN_WARNING "NMI watchdog doesn't know what hardware to touch\n"); -- cgit v1.1 From 7d5a78cd98c3a5eb83bd6a061c5ea6ef1e9b8fcb Mon Sep 17 00:00:00 2001 From: Aristeu Rozanski Date: Mon, 27 Oct 2008 12:42:35 -0400 Subject: x86, NMI watchdog: disable NMIs on LVT0 in case NMI watchdog is not working Impact: change NMI watchdog detection and disabling sequence Currently, if the NMI watchdog fails using IOAPIC method, it'll only disable interrupts on 8259 if the timer is passing thru it. This patch disables NMI delivery on LINT0 if the NMI watchdog initial test fails, just for safety. Signed-off-by: Aristeu Rozanski Cc: "Maciej W. Rozycki" Signed-off-by: Ingo Molnar --- arch/x86/kernel/nmi.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) (limited to 'arch/x86/kernel/nmi.c') diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 2c005fa..13316cf 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -131,6 +131,11 @@ static void report_broken_nmi(int cpu, int *prev_nmi_count) atomic_dec(&nmi_active); } +static void __acpi_nmi_disable(void *__unused) +{ + apic_write(APIC_LVT0, APIC_DM_NMI | APIC_LVT_MASKED); +} + int __init check_nmi_watchdog(void) { unsigned int *prev_nmi_count; @@ -179,8 +184,12 @@ int __init check_nmi_watchdog(void) kfree(prev_nmi_count); return 0; error: - if (nmi_watchdog == NMI_IO_APIC && !timer_through_8259) - disable_8259A_irq(0); + if (nmi_watchdog == NMI_IO_APIC) { + if (!timer_through_8259) + disable_8259A_irq(0); + on_each_cpu(__acpi_nmi_disable, NULL, 1); + } + #ifdef CONFIG_X86_32 timer_ack = 0; #endif @@ -285,11 +294,6 @@ void acpi_nmi_enable(void) on_each_cpu(__acpi_nmi_enable, NULL, 1); } -static void __acpi_nmi_disable(void *__unused) -{ - apic_write(APIC_LVT0, APIC_DM_NMI | APIC_LVT_MASKED); -} - /* * Disable timer based NMIs on all CPUs: */ -- cgit v1.1 From b062f841b569791d3054e975cd85f48562161565 Mon Sep 17 00:00:00 2001 From: Cyrill Gorcunov Date: Thu, 30 Oct 2008 19:16:46 +0300 Subject: x86: nmi - add sensible names to nmi_watchdog boot param Impact: introduce nmi_watchdog=lapic and nmi_watchdog=ioapic aliases Add sensible names as "lapic" and "ioapic" to nmi_watchdog boot parameter. Sometimes it is not that easy to recall what exactly nmi_watchdog=1 does mean so we allow the using of symbolic names here. Old numeric values remain valid. Signed-off-by: Cyrill Gorcunov Signed-off-by: Ingo Molnar --- arch/x86/kernel/nmi.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'arch/x86/kernel/nmi.c') diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 2c97f07..c4869e4 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -199,12 +199,17 @@ static int __init setup_nmi_watchdog(char *str) ++str; } - get_option(&str, &nmi); - - if (nmi >= NMI_INVALID) - return 0; + if (!strncmp(str, "lapic", 5)) + nmi_watchdog = NMI_LOCAL_APIC; + else if (!strncmp(str, "ioapic", 6)) + nmi_watchdog = NMI_IO_APIC; + else { + get_option(&str, &nmi); + if (nmi >= NMI_INVALID) + return 0; + nmi_watchdog = nmi; + } - nmi_watchdog = nmi; return 1; } __setup("nmi_watchdog=", setup_nmi_watchdog); -- cgit v1.1