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linux-stable/arch/x86/kernel/apic/hw_nmi.c

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nmi_watchdog: Add new, generic implementation, using perf events This is a new generic nmi_watchdog implementation using the perf events infrastructure as suggested by Ingo. The implementation is simple, just create an in-kernel perf event and register an overflow handler to check for cpu lockups. I created a generic implementation that lives in kernel/ and the hardware specific part that for now lives in arch/x86. This approach has a number of advantages: - It simplifies the x86 PMU implementation in the long run, in that it removes the hardcoded low-level PMU implementation that was the NMI watchdog before. - It allows new NMI watchdog features to be added in a central place. - It allows other architectures to enable the NMI watchdog, as long as they have perf events (that provide NMIs) implemented. - It also allows for more graceful co-existence of existing perf events apps and the NMI watchdog - before these changes the relationship was exclusive. (The NMI watchdog will 'spend' a perf event when enabled. In later iterations we might be able to piggyback from an existing NMI event without having to allocate a hardware event for the NMI watchdog - turning this into a no-hardware-cost feature.) As for compatibility, we'll keep the old NMI watchdog code as well until the new one can 100% replace it on all CPUs, old and new alike. That might take some time as the NMI watchdog has been ported to many CPU models. I have done light testing to make sure the framework works correctly and it does. v2: Set the correct timeout values based on the old nmi watchdog Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: gorcunov@gmail.com Cc: aris@redhat.com Cc: peterz@infradead.org LKML-Reference: <1265424425-31562-3-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-06 02:47:04 +00:00
/*
* HW NMI watchdog support
*
* started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
*
* Arch specific calls to support NMI watchdog
*
* Bits copied from original nmi.c file
*
*/
x86, watchdog: Fix build error in hw_nmi.c On some configs the following build error triggers: arch/x86/kernel/apic/hw_nmi.c:35: error: 'apic' undeclared (first use in this function) arch/x86/kernel/apic/hw_nmi.c:35: error: (Each undeclared identifier is reported only once arch/x86/kernel/apic/hw_nmi.c:35: error: for each function it appears in.) Because asm/apic.h was only included implicitly. Include it explicitly. Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> LKML-Reference: <1273713674-8434-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-13 07:12:39 +00:00
#include <asm/apic.h>
x86: Fix trigger_all_cpu_backtrace() implementation The following change fixes the x86 implementation of trigger_all_cpu_backtrace(), which was previously (accidentally, as far as I can tell) disabled to always return false as on architectures that do not implement this function. trigger_all_cpu_backtrace(), as defined in include/linux/nmi.h, should call arch_trigger_all_cpu_backtrace() if available, or return false if the underlying arch doesn't implement this function. x86 did provide a suitable arch_trigger_all_cpu_backtrace() implementation, but it wasn't actually being used because it was declared in asm/nmi.h, which linux/nmi.h doesn't include. Also, linux/nmi.h couldn't easily be fixed by including asm/nmi.h, because that file is not available on all architectures. I am proposing to fix this by moving the x86 definition of arch_trigger_all_cpu_backtrace() to asm/irq.h. Tested via: echo l > /proc/sysrq-trigger Before the change, this uses a fallback implementation which shows backtraces on active CPUs (using smp_call_function_interrupt() ) After the change, this shows NMI backtraces on all CPUs Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1370518875-1346-1-git-send-email-walken@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-06 11:41:15 +00:00
#include <asm/nmi.h>
nmi_watchdog: Add new, generic implementation, using perf events This is a new generic nmi_watchdog implementation using the perf events infrastructure as suggested by Ingo. The implementation is simple, just create an in-kernel perf event and register an overflow handler to check for cpu lockups. I created a generic implementation that lives in kernel/ and the hardware specific part that for now lives in arch/x86. This approach has a number of advantages: - It simplifies the x86 PMU implementation in the long run, in that it removes the hardcoded low-level PMU implementation that was the NMI watchdog before. - It allows new NMI watchdog features to be added in a central place. - It allows other architectures to enable the NMI watchdog, as long as they have perf events (that provide NMIs) implemented. - It also allows for more graceful co-existence of existing perf events apps and the NMI watchdog - before these changes the relationship was exclusive. (The NMI watchdog will 'spend' a perf event when enabled. In later iterations we might be able to piggyback from an existing NMI event without having to allocate a hardware event for the NMI watchdog - turning this into a no-hardware-cost feature.) As for compatibility, we'll keep the old NMI watchdog code as well until the new one can 100% replace it on all CPUs, old and new alike. That might take some time as the NMI watchdog has been ported to many CPU models. I have done light testing to make sure the framework works correctly and it does. v2: Set the correct timeout values based on the old nmi watchdog Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: gorcunov@gmail.com Cc: aris@redhat.com Cc: peterz@infradead.org LKML-Reference: <1265424425-31562-3-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-06 02:47:04 +00:00
#include <linux/cpumask.h>
x86: Move trigger_all_cpu_backtrace to its own die_notifier As part of the transition of the nmi watchdog to something more generic, the trigger_all_cpu_backtrace code is getting left behind. Put it in its own die_notifier so it can still be used. V2: - use arch_spin_locks Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-6-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-05-07 21:11:48 +00:00
#include <linux/kdebug.h>
#include <linux/notifier.h>
#include <linux/kprobes.h>
nmi_watchdog: Add new, generic implementation, using perf events This is a new generic nmi_watchdog implementation using the perf events infrastructure as suggested by Ingo. The implementation is simple, just create an in-kernel perf event and register an overflow handler to check for cpu lockups. I created a generic implementation that lives in kernel/ and the hardware specific part that for now lives in arch/x86. This approach has a number of advantages: - It simplifies the x86 PMU implementation in the long run, in that it removes the hardcoded low-level PMU implementation that was the NMI watchdog before. - It allows new NMI watchdog features to be added in a central place. - It allows other architectures to enable the NMI watchdog, as long as they have perf events (that provide NMIs) implemented. - It also allows for more graceful co-existence of existing perf events apps and the NMI watchdog - before these changes the relationship was exclusive. (The NMI watchdog will 'spend' a perf event when enabled. In later iterations we might be able to piggyback from an existing NMI event without having to allocate a hardware event for the NMI watchdog - turning this into a no-hardware-cost feature.) As for compatibility, we'll keep the old NMI watchdog code as well until the new one can 100% replace it on all CPUs, old and new alike. That might take some time as the NMI watchdog has been ported to many CPU models. I have done light testing to make sure the framework works correctly and it does. v2: Set the correct timeout values based on the old nmi watchdog Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: gorcunov@gmail.com Cc: aris@redhat.com Cc: peterz@infradead.org LKML-Reference: <1265424425-31562-3-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-06 02:47:04 +00:00
#include <linux/nmi.h>
#include <linux/module.h>
x86: Stop including <linux/delay.h> in two asm header files Stop including <linux/delay.h> in x86 header files which don't need it. This will let the compiler complain when this header is not included by source files when it should, so that contributors can fix the problem before building on other architectures starts to fail. Credits go to Geert for the idea. Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: James E.J. Bottomley <James.Bottomley@suse.de> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> LKML-Reference: <20110325152014.297890ec@endymion.delvare> [ this also fixes an upstream build bug in drivers/media/rc/ite-cir.c ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-25 14:20:14 +00:00
#include <linux/delay.h>
nmi_watchdog: Add new, generic implementation, using perf events This is a new generic nmi_watchdog implementation using the perf events infrastructure as suggested by Ingo. The implementation is simple, just create an in-kernel perf event and register an overflow handler to check for cpu lockups. I created a generic implementation that lives in kernel/ and the hardware specific part that for now lives in arch/x86. This approach has a number of advantages: - It simplifies the x86 PMU implementation in the long run, in that it removes the hardcoded low-level PMU implementation that was the NMI watchdog before. - It allows new NMI watchdog features to be added in a central place. - It allows other architectures to enable the NMI watchdog, as long as they have perf events (that provide NMIs) implemented. - It also allows for more graceful co-existence of existing perf events apps and the NMI watchdog - before these changes the relationship was exclusive. (The NMI watchdog will 'spend' a perf event when enabled. In later iterations we might be able to piggyback from an existing NMI event without having to allocate a hardware event for the NMI watchdog - turning this into a no-hardware-cost feature.) As for compatibility, we'll keep the old NMI watchdog code as well until the new one can 100% replace it on all CPUs, old and new alike. That might take some time as the NMI watchdog has been ported to many CPU models. I have done light testing to make sure the framework works correctly and it does. v2: Set the correct timeout values based on the old nmi watchdog Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: gorcunov@gmail.com Cc: aris@redhat.com Cc: peterz@infradead.org LKML-Reference: <1265424425-31562-3-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-06 02:47:04 +00:00
x86, nmi_watchdog: Remove the old nmi_watchdog Now that we have a new nmi_watchdog that is more generic and sits on top of the perf subsystem, we really do not need the old nmi_watchdog any more. In addition, the old nmi_watchdog doesn't really work if you are using the default clocksource, hpet. The old nmi_watchdog code relied on local apic interrupts to determine if the cpu is still alive. With hpet as the clocksource, these interrupts don't increment any more and the old nmi_watchdog triggers false postives. This piece removes the old nmi_watchdog code and stubs out any variables and functions calls. The stubs are the same ones used by the new nmi_watchdog code, so it should be well tested. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: fweisbec@gmail.com Cc: gorcunov@openvz.org LKML-Reference: <1289578944-28564-2-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-12 16:22:23 +00:00
#ifdef CONFIG_HARDLOCKUP_DETECTOR
watchdog: Change the default timeout and configure nmi watchdog period based on watchdog_thresh Before the conversion of the NMI watchdog to perf event, the watchdog timeout was 5 seconds. Now it is 60 seconds. For my particular application, netbooks, 5 seconds was a better timeout. With a short timeout, we catch faults earlier and are able to send back a panic. With a 60 second timeout, the user is unlikely to wait and will instead hit the power button, causing us to lose the panic info. This change configures the NMI period to watchdog_thresh and sets the softlockup_thresh to watchdog_thresh * 2. In addition, watchdog_thresh was reduced to 10 seconds as suggested by Ingo Molnar. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Cc: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/1306127423-3347-4-git-send-email-msb@chromium.org Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <20110517071642.GF22305@elte.hu>
2011-05-23 05:10:23 +00:00
u64 hw_nmi_get_sample_period(int watchdog_thresh)
nmi_watchdog: Compile and portability fixes The original patch was x86_64 centric. Changed the code to make it less so. ested by building and running on a powerpc. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: peterz@infradead.org Cc: gorcunov@gmail.com Cc: aris@redhat.com LKML-Reference: <1266013161-31197-2-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-12 22:19:19 +00:00
{
watchdog: Change the default timeout and configure nmi watchdog period based on watchdog_thresh Before the conversion of the NMI watchdog to perf event, the watchdog timeout was 5 seconds. Now it is 60 seconds. For my particular application, netbooks, 5 seconds was a better timeout. With a short timeout, we catch faults earlier and are able to send back a panic. With a 60 second timeout, the user is unlikely to wait and will instead hit the power button, causing us to lose the panic info. This change configures the NMI period to watchdog_thresh and sets the softlockup_thresh to watchdog_thresh * 2. In addition, watchdog_thresh was reduced to 10 seconds as suggested by Ingo Molnar. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Cc: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/1306127423-3347-4-git-send-email-msb@chromium.org Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <20110517071642.GF22305@elte.hu>
2011-05-23 05:10:23 +00:00
return (u64)(cpu_khz) * 1000 * watchdog_thresh;
nmi_watchdog: Compile and portability fixes The original patch was x86_64 centric. Changed the code to make it less so. ested by building and running on a powerpc. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: peterz@infradead.org Cc: gorcunov@gmail.com Cc: aris@redhat.com LKML-Reference: <1266013161-31197-2-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-12 22:19:19 +00:00
}
x86, nmi_watchdog: Remove the old nmi_watchdog Now that we have a new nmi_watchdog that is more generic and sits on top of the perf subsystem, we really do not need the old nmi_watchdog any more. In addition, the old nmi_watchdog doesn't really work if you are using the default clocksource, hpet. The old nmi_watchdog code relied on local apic interrupts to determine if the cpu is still alive. With hpet as the clocksource, these interrupts don't increment any more and the old nmi_watchdog triggers false postives. This piece removes the old nmi_watchdog code and stubs out any variables and functions calls. The stubs are the same ones used by the new nmi_watchdog code, so it should be well tested. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: fweisbec@gmail.com Cc: gorcunov@openvz.org LKML-Reference: <1289578944-28564-2-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-12 16:22:23 +00:00
#endif
nmi_watchdog: Compile and portability fixes The original patch was x86_64 centric. Changed the code to make it less so. ested by building and running on a powerpc. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: peterz@infradead.org Cc: gorcunov@gmail.com Cc: aris@redhat.com LKML-Reference: <1266013161-31197-2-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-12 22:19:19 +00:00
x86: Address 'unused' warning in hw_nmi.c again arch/x86/kernel/apic/hw_nmi.c:29: warning: backtrace_mask defined but not used commit 0e2af2a9(x86, hw_nmi: Move backtrace_mask declaration under ARCH_HAS_NMI_WATCHDOG) addressed this warning, but it was reintroduced by commit 5f2b0ba4(x86, nmi_watchdog: Remove the old nmi_watchdog). Move backtrace_mask into the #ifdef arch_trigger_all_cpu_backtrace section again. Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <AANLkTi=rcc38QzoKa6LFy4m++-p_9=Zt4_kDQE=GeKxf@mail.gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-12-09 08:47:34 +00:00
#ifdef arch_trigger_all_cpu_backtrace
x86, hw_nmi: Move backtrace_mask declaration under ARCH_HAS_NMI_WATCHDOG backtrace_mask has been used under the code context of ARCH_HAS_NMI_WATCHDOG. So put it into that context. We were warned by the following warning: arch/x86/kernel/apic/hw_nmi.c:21: warning: ‘backtrace_mask’ defined but not used Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com> Signed-off-by: Don Zickus <dzickus@redhat.com> LKML-Reference: <1289573455-3410-2-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-12 14:50:54 +00:00
/* For reliability, we're prepared to waste bits here. */
static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
x86: Avoid calling arch_trigger_all_cpu_backtrace() at the same time The spin_lock_debug/rcu_cpu_stall detector uses trigger_all_cpu_backtrace() to dump cpu backtrace. Therefore it is possible that trigger_all_cpu_backtrace() could be called at the same time on different CPUs, which triggers and 'unknown reason NMI' warning. The following case illustrates the problem: CPU1 CPU2 ... CPU N trigger_all_cpu_backtrace() set "backtrace_mask" to cpu mask | generate NMI interrupts generate NMI interrupts ... \ | / \ | / The "backtrace_mask" will be cleaned by the first NMI interrupt at nmi_watchdog_tick(), then the following NMI interrupts generated by other cpus's arch_trigger_all_cpu_backtrace() will be taken as unknown reason NMI interrupts. This patch uses a test_and_set to avoid the problem, and stop the arch_trigger_all_cpu_backtrace() from calling to avoid dumping a double cpu backtrace info when there is already a trigger_all_cpu_backtrace() in progress. Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com> Reviewed-by: Bruce Ashfield <bruce.ashfield@windriver.com> Cc: fweisbec@gmail.com LKML-Reference: <1294198689-15447-2-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Don Zickus <dzickus@redhat.com>
2011-01-05 03:38:08 +00:00
/* "in progress" flag of arch_trigger_all_cpu_backtrace */
static unsigned long backtrace_flag;
nmi_watchdog: Add new, generic implementation, using perf events This is a new generic nmi_watchdog implementation using the perf events infrastructure as suggested by Ingo. The implementation is simple, just create an in-kernel perf event and register an overflow handler to check for cpu lockups. I created a generic implementation that lives in kernel/ and the hardware specific part that for now lives in arch/x86. This approach has a number of advantages: - It simplifies the x86 PMU implementation in the long run, in that it removes the hardcoded low-level PMU implementation that was the NMI watchdog before. - It allows new NMI watchdog features to be added in a central place. - It allows other architectures to enable the NMI watchdog, as long as they have perf events (that provide NMIs) implemented. - It also allows for more graceful co-existence of existing perf events apps and the NMI watchdog - before these changes the relationship was exclusive. (The NMI watchdog will 'spend' a perf event when enabled. In later iterations we might be able to piggyback from an existing NMI event without having to allocate a hardware event for the NMI watchdog - turning this into a no-hardware-cost feature.) As for compatibility, we'll keep the old NMI watchdog code as well until the new one can 100% replace it on all CPUs, old and new alike. That might take some time as the NMI watchdog has been ported to many CPU models. I have done light testing to make sure the framework works correctly and it does. v2: Set the correct timeout values based on the old nmi watchdog Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: gorcunov@gmail.com Cc: aris@redhat.com Cc: peterz@infradead.org LKML-Reference: <1265424425-31562-3-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-06 02:47:04 +00:00
void arch_trigger_all_cpu_backtrace(void)
{
int i;
x86: Avoid calling arch_trigger_all_cpu_backtrace() at the same time The spin_lock_debug/rcu_cpu_stall detector uses trigger_all_cpu_backtrace() to dump cpu backtrace. Therefore it is possible that trigger_all_cpu_backtrace() could be called at the same time on different CPUs, which triggers and 'unknown reason NMI' warning. The following case illustrates the problem: CPU1 CPU2 ... CPU N trigger_all_cpu_backtrace() set "backtrace_mask" to cpu mask | generate NMI interrupts generate NMI interrupts ... \ | / \ | / The "backtrace_mask" will be cleaned by the first NMI interrupt at nmi_watchdog_tick(), then the following NMI interrupts generated by other cpus's arch_trigger_all_cpu_backtrace() will be taken as unknown reason NMI interrupts. This patch uses a test_and_set to avoid the problem, and stop the arch_trigger_all_cpu_backtrace() from calling to avoid dumping a double cpu backtrace info when there is already a trigger_all_cpu_backtrace() in progress. Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com> Reviewed-by: Bruce Ashfield <bruce.ashfield@windriver.com> Cc: fweisbec@gmail.com LKML-Reference: <1294198689-15447-2-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Don Zickus <dzickus@redhat.com>
2011-01-05 03:38:08 +00:00
if (test_and_set_bit(0, &backtrace_flag))
/*
* If there is already a trigger_all_cpu_backtrace() in progress
* (backtrace_flag == 1), don't output double cpu dump infos.
*/
return;
nmi_watchdog: Add new, generic implementation, using perf events This is a new generic nmi_watchdog implementation using the perf events infrastructure as suggested by Ingo. The implementation is simple, just create an in-kernel perf event and register an overflow handler to check for cpu lockups. I created a generic implementation that lives in kernel/ and the hardware specific part that for now lives in arch/x86. This approach has a number of advantages: - It simplifies the x86 PMU implementation in the long run, in that it removes the hardcoded low-level PMU implementation that was the NMI watchdog before. - It allows new NMI watchdog features to be added in a central place. - It allows other architectures to enable the NMI watchdog, as long as they have perf events (that provide NMIs) implemented. - It also allows for more graceful co-existence of existing perf events apps and the NMI watchdog - before these changes the relationship was exclusive. (The NMI watchdog will 'spend' a perf event when enabled. In later iterations we might be able to piggyback from an existing NMI event without having to allocate a hardware event for the NMI watchdog - turning this into a no-hardware-cost feature.) As for compatibility, we'll keep the old NMI watchdog code as well until the new one can 100% replace it on all CPUs, old and new alike. That might take some time as the NMI watchdog has been ported to many CPU models. I have done light testing to make sure the framework works correctly and it does. v2: Set the correct timeout values based on the old nmi watchdog Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: gorcunov@gmail.com Cc: aris@redhat.com Cc: peterz@infradead.org LKML-Reference: <1265424425-31562-3-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-06 02:47:04 +00:00
cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
printk(KERN_INFO "sending NMI to all CPUs:\n");
apic->send_IPI_all(NMI_VECTOR);
/* Wait for up to 10 seconds for all CPUs to do the backtrace */
for (i = 0; i < 10 * 1000; i++) {
if (cpumask_empty(to_cpumask(backtrace_mask)))
break;
mdelay(1);
}
x86: Avoid calling arch_trigger_all_cpu_backtrace() at the same time The spin_lock_debug/rcu_cpu_stall detector uses trigger_all_cpu_backtrace() to dump cpu backtrace. Therefore it is possible that trigger_all_cpu_backtrace() could be called at the same time on different CPUs, which triggers and 'unknown reason NMI' warning. The following case illustrates the problem: CPU1 CPU2 ... CPU N trigger_all_cpu_backtrace() set "backtrace_mask" to cpu mask | generate NMI interrupts generate NMI interrupts ... \ | / \ | / The "backtrace_mask" will be cleaned by the first NMI interrupt at nmi_watchdog_tick(), then the following NMI interrupts generated by other cpus's arch_trigger_all_cpu_backtrace() will be taken as unknown reason NMI interrupts. This patch uses a test_and_set to avoid the problem, and stop the arch_trigger_all_cpu_backtrace() from calling to avoid dumping a double cpu backtrace info when there is already a trigger_all_cpu_backtrace() in progress. Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com> Reviewed-by: Bruce Ashfield <bruce.ashfield@windriver.com> Cc: fweisbec@gmail.com LKML-Reference: <1294198689-15447-2-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Don Zickus <dzickus@redhat.com>
2011-01-05 03:38:08 +00:00
clear_bit(0, &backtrace_flag);
smp_mb__after_clear_bit();
nmi_watchdog: Add new, generic implementation, using perf events This is a new generic nmi_watchdog implementation using the perf events infrastructure as suggested by Ingo. The implementation is simple, just create an in-kernel perf event and register an overflow handler to check for cpu lockups. I created a generic implementation that lives in kernel/ and the hardware specific part that for now lives in arch/x86. This approach has a number of advantages: - It simplifies the x86 PMU implementation in the long run, in that it removes the hardcoded low-level PMU implementation that was the NMI watchdog before. - It allows new NMI watchdog features to be added in a central place. - It allows other architectures to enable the NMI watchdog, as long as they have perf events (that provide NMIs) implemented. - It also allows for more graceful co-existence of existing perf events apps and the NMI watchdog - before these changes the relationship was exclusive. (The NMI watchdog will 'spend' a perf event when enabled. In later iterations we might be able to piggyback from an existing NMI event without having to allocate a hardware event for the NMI watchdog - turning this into a no-hardware-cost feature.) As for compatibility, we'll keep the old NMI watchdog code as well until the new one can 100% replace it on all CPUs, old and new alike. That might take some time as the NMI watchdog has been ported to many CPU models. I have done light testing to make sure the framework works correctly and it does. v2: Set the correct timeout values based on the old nmi watchdog Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: gorcunov@gmail.com Cc: aris@redhat.com Cc: peterz@infradead.org LKML-Reference: <1265424425-31562-3-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-06 02:47:04 +00:00
}
x86: Move trigger_all_cpu_backtrace to its own die_notifier As part of the transition of the nmi watchdog to something more generic, the trigger_all_cpu_backtrace code is getting left behind. Put it in its own die_notifier so it can still be used. V2: - use arch_spin_locks Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-6-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-05-07 21:11:48 +00:00
static int __kprobes
x86, nmi: Wire up NMI handlers to new routines Just convert all the files that have an nmi handler to the new routines. Most of it is straight forward conversion. A couple of places needed some tweaking like kgdb which separates the debug notifier from the nmi handler and mce removes a call to notify_die. [Thanks to Ying for finding out the history behind that mce call https://lkml.org/lkml/2010/5/27/114 And Boris responding that he would like to remove that call because of it https://lkml.org/lkml/2011/9/21/163] The things that get converted are the registeration/unregistration routines and the nmi handler itself has its args changed along with code removal to check which list it is on (most are on one NMI list except for kgdb which has both an NMI routine and an NMI Unknown routine). Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Corey Minyard <minyard@acm.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Robert Richter <robert.richter@amd.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Corey Minyard <minyard@acm.org> Cc: Jack Steiner <steiner@sgi.com> Link: http://lkml.kernel.org/r/1317409584-23662-4-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-09-30 19:06:21 +00:00
arch_trigger_all_cpu_backtrace_handler(unsigned int cmd, struct pt_regs *regs)
x86: Move trigger_all_cpu_backtrace to its own die_notifier As part of the transition of the nmi watchdog to something more generic, the trigger_all_cpu_backtrace code is getting left behind. Put it in its own die_notifier so it can still be used. V2: - use arch_spin_locks Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-6-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-05-07 21:11:48 +00:00
{
x86: Only call smp_processor_id in non-preempt cases There are some paths that walk the die_chain with preemption on. Make sure we are in an NMI call before we start doing anything. This was triggered by do_general_protection calling notify_die with DIE_GPF. Reported-by: Jan Kiszka <jan.kiszka@web.de> Signed-off-by: Don Zickus <dzickus@redhat.com> LKML-Reference: <1294198689-15447-1-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-05 03:38:07 +00:00
int cpu;
x86: Move trigger_all_cpu_backtrace to its own die_notifier As part of the transition of the nmi watchdog to something more generic, the trigger_all_cpu_backtrace code is getting left behind. Put it in its own die_notifier so it can still be used. V2: - use arch_spin_locks Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-6-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-05-07 21:11:48 +00:00
x86: Only call smp_processor_id in non-preempt cases There are some paths that walk the die_chain with preemption on. Make sure we are in an NMI call before we start doing anything. This was triggered by do_general_protection calling notify_die with DIE_GPF. Reported-by: Jan Kiszka <jan.kiszka@web.de> Signed-off-by: Don Zickus <dzickus@redhat.com> LKML-Reference: <1294198689-15447-1-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-05 03:38:07 +00:00
cpu = smp_processor_id();
x86: Move trigger_all_cpu_backtrace to its own die_notifier As part of the transition of the nmi watchdog to something more generic, the trigger_all_cpu_backtrace code is getting left behind. Put it in its own die_notifier so it can still be used. V2: - use arch_spin_locks Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-6-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-05-07 21:11:48 +00:00
if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
arch_spin_lock(&lock);
printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
show_regs(regs);
arch_spin_unlock(&lock);
cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
x86, nmi: Wire up NMI handlers to new routines Just convert all the files that have an nmi handler to the new routines. Most of it is straight forward conversion. A couple of places needed some tweaking like kgdb which separates the debug notifier from the nmi handler and mce removes a call to notify_die. [Thanks to Ying for finding out the history behind that mce call https://lkml.org/lkml/2010/5/27/114 And Boris responding that he would like to remove that call because of it https://lkml.org/lkml/2011/9/21/163] The things that get converted are the registeration/unregistration routines and the nmi handler itself has its args changed along with code removal to check which list it is on (most are on one NMI list except for kgdb which has both an NMI routine and an NMI Unknown routine). Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Corey Minyard <minyard@acm.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Robert Richter <robert.richter@amd.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Corey Minyard <minyard@acm.org> Cc: Jack Steiner <steiner@sgi.com> Link: http://lkml.kernel.org/r/1317409584-23662-4-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-09-30 19:06:21 +00:00
return NMI_HANDLED;
x86: Move trigger_all_cpu_backtrace to its own die_notifier As part of the transition of the nmi watchdog to something more generic, the trigger_all_cpu_backtrace code is getting left behind. Put it in its own die_notifier so it can still be used. V2: - use arch_spin_locks Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-6-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-05-07 21:11:48 +00:00
}
x86, nmi: Wire up NMI handlers to new routines Just convert all the files that have an nmi handler to the new routines. Most of it is straight forward conversion. A couple of places needed some tweaking like kgdb which separates the debug notifier from the nmi handler and mce removes a call to notify_die. [Thanks to Ying for finding out the history behind that mce call https://lkml.org/lkml/2010/5/27/114 And Boris responding that he would like to remove that call because of it https://lkml.org/lkml/2011/9/21/163] The things that get converted are the registeration/unregistration routines and the nmi handler itself has its args changed along with code removal to check which list it is on (most are on one NMI list except for kgdb which has both an NMI routine and an NMI Unknown routine). Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Corey Minyard <minyard@acm.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Robert Richter <robert.richter@amd.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Corey Minyard <minyard@acm.org> Cc: Jack Steiner <steiner@sgi.com> Link: http://lkml.kernel.org/r/1317409584-23662-4-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-09-30 19:06:21 +00:00
return NMI_DONE;
x86: Move trigger_all_cpu_backtrace to its own die_notifier As part of the transition of the nmi watchdog to something more generic, the trigger_all_cpu_backtrace code is getting left behind. Put it in its own die_notifier so it can still be used. V2: - use arch_spin_locks Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-6-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-05-07 21:11:48 +00:00
}
static int __init register_trigger_all_cpu_backtrace(void)
{
x86, nmi: Wire up NMI handlers to new routines Just convert all the files that have an nmi handler to the new routines. Most of it is straight forward conversion. A couple of places needed some tweaking like kgdb which separates the debug notifier from the nmi handler and mce removes a call to notify_die. [Thanks to Ying for finding out the history behind that mce call https://lkml.org/lkml/2010/5/27/114 And Boris responding that he would like to remove that call because of it https://lkml.org/lkml/2011/9/21/163] The things that get converted are the registeration/unregistration routines and the nmi handler itself has its args changed along with code removal to check which list it is on (most are on one NMI list except for kgdb which has both an NMI routine and an NMI Unknown routine). Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Corey Minyard <minyard@acm.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Robert Richter <robert.richter@amd.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Corey Minyard <minyard@acm.org> Cc: Jack Steiner <steiner@sgi.com> Link: http://lkml.kernel.org/r/1317409584-23662-4-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-09-30 19:06:21 +00:00
register_nmi_handler(NMI_LOCAL, arch_trigger_all_cpu_backtrace_handler,
0, "arch_bt");
x86: Move trigger_all_cpu_backtrace to its own die_notifier As part of the transition of the nmi watchdog to something more generic, the trigger_all_cpu_backtrace code is getting left behind. Put it in its own die_notifier so it can still be used. V2: - use arch_spin_locks Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-6-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-05-07 21:11:48 +00:00
return 0;
}
early_initcall(register_trigger_all_cpu_backtrace);
nmi_watchdog: Fix undefined 'apic' build bug Ingo provided me a config that fails to compile with: arch/x86/built-in.o: In function `arch_trigger_all_cpu_backtrace': (.text+0x17e78): undefined reference to `apic' make: *** [.tmp_vmlinux1] Error 1 I realized I changed the compile behaviour of the nmi code by not wrapping it with CONFIG_LOCAL_APIC. To fix this I add a compile check for ARCH_HAS_NMI_WATCHDOG around arch_trigger_all_cpu_backtrace. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: a.p.zijlstra@chello.nl Cc: gorcunov@gmail.com Cc: aris@redhat.com LKML-Reference: <1266548212-24243-1-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-19 02:56:52 +00:00
#endif
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