diff options
| -rw-r--r-- | arch/x86/kernel/ftrace.c | 4 | ||||
| -rw-r--r-- | include/linux/ftrace_irq.h | 8 | ||||
| -rw-r--r-- | kernel/trace/ring_buffer.c | 43 |
3 files changed, 15 insertions, 40 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 918073c6681b..d74d75e0952d 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -113,7 +113,7 @@ static void ftrace_mod_code(void) MCOUNT_INSN_SIZE); } -void arch_ftrace_nmi_enter(void) +void ftrace_nmi_enter(void) { atomic_inc(&nmi_running); /* Must have nmi_running seen before reading write flag */ @@ -124,7 +124,7 @@ void arch_ftrace_nmi_enter(void) } } -void arch_ftrace_nmi_exit(void) +void ftrace_nmi_exit(void) { /* Finish all executions before clearing nmi_running */ smp_wmb(); diff --git a/include/linux/ftrace_irq.h b/include/linux/ftrace_irq.h index 29de6779a963..dca7bf8cffe2 100644 --- a/include/linux/ftrace_irq.h +++ b/include/linux/ftrace_irq.h @@ -3,14 +3,6 @@ #ifdef CONFIG_FTRACE_NMI_ENTER -extern void arch_ftrace_nmi_enter(void); -extern void arch_ftrace_nmi_exit(void); -#else -static inline void arch_ftrace_nmi_enter(void) { } -static inline void arch_ftrace_nmi_exit(void) { } -#endif - -#ifdef CONFIG_RING_BUFFER extern void ftrace_nmi_enter(void); extern void ftrace_nmi_exit(void); #else diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index a60a6a852f42..5ee344417cd5 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -8,6 +8,7 @@ #include <linux/spinlock.h> #include <linux/debugfs.h> #include <linux/uaccess.h> +#include <linux/hardirq.h> #include <linux/module.h> #include <linux/percpu.h> #include <linux/mutex.h> @@ -20,35 +21,6 @@ #include "trace.h" /* - * Since the write to the buffer is still not fully lockless, - * we must be careful with NMIs. The locks in the writers - * are taken when a write crosses to a new page. The locks - * protect against races with the readers (this will soon - * be fixed with a lockless solution). - * - * Because we can not protect against NMIs, and we want to - * keep traces reentrant, we need to manage what happens - * when we are in an NMI. - */ -static DEFINE_PER_CPU(int, rb_in_nmi); - -void ftrace_nmi_enter(void) -{ - __get_cpu_var(rb_in_nmi)++; - /* call arch specific handler too */ - arch_ftrace_nmi_enter(); -} - -void ftrace_nmi_exit(void) -{ - arch_ftrace_nmi_exit(); - __get_cpu_var(rb_in_nmi)--; - /* NMIs are not recursive */ - WARN_ON_ONCE(__get_cpu_var(rb_in_nmi)); -} - - -/* * A fast way to enable or disable all ring buffers is to * call tracing_on or tracing_off. Turning off the ring buffers * prevents all ring buffers from being recorded to. @@ -1027,12 +999,23 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, local_irq_save(flags); /* + * Since the write to the buffer is still not + * fully lockless, we must be careful with NMIs. + * The locks in the writers are taken when a write + * crosses to a new page. The locks protect against + * races with the readers (this will soon be fixed + * with a lockless solution). + * + * Because we can not protect against NMIs, and we + * want to keep traces reentrant, we need to manage + * what happens when we are in an NMI. + * * NMIs can happen after we take the lock. * If we are in an NMI, only take the lock * if it is not already taken. Otherwise * simply fail. */ - if (unlikely(__get_cpu_var(rb_in_nmi))) { + if (unlikely(in_nmi())) { if (!__raw_spin_trylock(&cpu_buffer->lock)) goto out_unlock; } else |