path: root/arch
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authorMichel Lespinasse <walken@google.com>2013-06-06 04:41:15 -0700
committerIngo Molnar <mingo@kernel.org>2013-06-20 14:00:21 +0200
commitb52e0a7c4e4100f8683af508664e60e1603070f9 (patch)
tree1688d563baa6a011bb2945d79050ecb008da9821 /arch
parent949785996ec2250fa958fc3a924e5186e9a8fa2c (diff)
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>
Diffstat (limited to 'arch')
3 files changed, 7 insertions, 3 deletions
diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index ba870bb6dd8..57873beb329 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -41,4 +41,9 @@ extern int vector_used_by_percpu_irq(unsigned int vector);
extern void init_ISA_irqs(void);
+void arch_trigger_all_cpu_backtrace(void);
+#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
#endif /* _ASM_X86_IRQ_H */
diff --git a/arch/x86/include/asm/nmi.h b/arch/x86/include/asm/nmi.h
index c0fa356e90d..86f9301903c 100644
--- a/arch/x86/include/asm/nmi.h
+++ b/arch/x86/include/asm/nmi.h
@@ -18,9 +18,7 @@ extern int proc_nmi_enabled(struct ctl_table *, int ,
void __user *, size_t *, loff_t *);
extern int unknown_nmi_panic;
-void arch_trigger_all_cpu_backtrace(void);
-#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
+#endif /* CONFIG_X86_LOCAL_APIC */
#define NMI_FLAG_FIRST 1
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index 31cb9ae992b..a698d7165c9 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -9,6 +9,7 @@
#include <asm/apic.h>
+#include <asm/nmi.h>
#include <linux/cpumask.h>
#include <linux/kdebug.h>