forked from luck/tmp_suning_uos_patched
ring-buffer: use generic version of in_nmi
Impact: clean up Now that a generic in_nmi is available, this patch removes the special code in the ring_buffer and implements the in_nmi generic version instead. With this change, I was also able to rename the "arch_ftrace_nmi_enter" back to "ftrace_nmi_enter" and remove the code from the ring buffer. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
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@ -113,7 +113,7 @@ static void ftrace_mod_code(void)
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MCOUNT_INSN_SIZE);
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}
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void arch_ftrace_nmi_enter(void)
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void ftrace_nmi_enter(void)
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{
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atomic_inc(&nmi_running);
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/* Must have nmi_running seen before reading write flag */
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@ -124,7 +124,7 @@ void arch_ftrace_nmi_enter(void)
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}
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}
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void arch_ftrace_nmi_exit(void)
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void ftrace_nmi_exit(void)
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{
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/* Finish all executions before clearing nmi_running */
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smp_wmb();
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@ -3,14 +3,6 @@
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#ifdef CONFIG_FTRACE_NMI_ENTER
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extern void arch_ftrace_nmi_enter(void);
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extern void arch_ftrace_nmi_exit(void);
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#else
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static inline void arch_ftrace_nmi_enter(void) { }
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static inline void arch_ftrace_nmi_exit(void) { }
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#endif
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#ifdef CONFIG_RING_BUFFER
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extern void ftrace_nmi_enter(void);
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extern void ftrace_nmi_exit(void);
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#else
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@ -8,6 +8,7 @@
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#include <linux/spinlock.h>
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#include <linux/debugfs.h>
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#include <linux/uaccess.h>
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#include <linux/hardirq.h>
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#include <linux/module.h>
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#include <linux/percpu.h>
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#include <linux/mutex.h>
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@ -19,35 +20,6 @@
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#include "trace.h"
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/*
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* Since the write to the buffer is still not fully lockless,
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* we must be careful with NMIs. The locks in the writers
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* are taken when a write crosses to a new page. The locks
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* protect against races with the readers (this will soon
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* be fixed with a lockless solution).
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*
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* Because we can not protect against NMIs, and we want to
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* keep traces reentrant, we need to manage what happens
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* when we are in an NMI.
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*/
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static DEFINE_PER_CPU(int, rb_in_nmi);
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void ftrace_nmi_enter(void)
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{
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__get_cpu_var(rb_in_nmi)++;
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/* call arch specific handler too */
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arch_ftrace_nmi_enter();
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}
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void ftrace_nmi_exit(void)
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{
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arch_ftrace_nmi_exit();
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__get_cpu_var(rb_in_nmi)--;
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/* NMIs are not recursive */
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WARN_ON_ONCE(__get_cpu_var(rb_in_nmi));
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}
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/*
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* A fast way to enable or disable all ring buffers is to
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* call tracing_on or tracing_off. Turning off the ring buffers
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@ -1027,12 +999,23 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
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local_irq_save(flags);
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/*
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* Since the write to the buffer is still not
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* fully lockless, we must be careful with NMIs.
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* The locks in the writers are taken when a write
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* crosses to a new page. The locks protect against
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* races with the readers (this will soon be fixed
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* with a lockless solution).
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*
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* Because we can not protect against NMIs, and we
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* want to keep traces reentrant, we need to manage
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* what happens when we are in an NMI.
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*
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* NMIs can happen after we take the lock.
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* If we are in an NMI, only take the lock
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* if it is not already taken. Otherwise
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* simply fail.
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*/
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if (unlikely(__get_cpu_var(rb_in_nmi))) {
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if (unlikely(in_nmi())) {
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if (!__raw_spin_trylock(&cpu_buffer->lock))
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goto out_unlock;
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} else
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