diff options
| -rw-r--r-- | arch/x86/kernel/dumpstack.c | 6 | ||||
| -rw-r--r-- | include/linux/ftrace.h | 13 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 1 | ||||
| -rw-r--r-- | kernel/trace/trace_hw_branches.c | 29 |
4 files changed, 41 insertions, 8 deletions
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 6b1f6f6f8661..077c9ea655fc 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -14,6 +14,7 @@ #include <linux/bug.h> #include <linux/nmi.h> #include <linux/sysfs.h> +#include <linux/ftrace.h> #include <asm/stacktrace.h> @@ -195,6 +196,11 @@ unsigned __kprobes long oops_begin(void) int cpu; unsigned long flags; + /* notify the hw-branch tracer so it may disable tracing and + add the last trace to the trace buffer - + the earlier this happens, the more useful the trace. */ + trace_hw_branch_oops(); + oops_enter(); /* racy, but better than risking deadlock. */ diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 054721487574..9f7880d87c39 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -496,4 +496,17 @@ static inline int test_tsk_trace_graph(struct task_struct *tsk) #endif /* CONFIG_TRACING */ + +#ifdef CONFIG_HW_BRANCH_TRACER + +void trace_hw_branch(u64 from, u64 to); +void trace_hw_branch_oops(void); + +#else /* CONFIG_HW_BRANCH_TRACER */ + +static inline void trace_hw_branch(u64 from, u64 to) {} +static inline void trace_hw_branch_oops(void) {} + +#endif /* CONFIG_HW_BRANCH_TRACER */ + #endif /* _LINUX_FTRACE_H */ diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 54b72781e920..b96037d970df 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -438,7 +438,6 @@ void trace_function(struct trace_array *tr, void trace_graph_return(struct ftrace_graph_ret *trace); int trace_graph_entry(struct ftrace_graph_ent *trace); -void trace_hw_branch(struct trace_array *tr, u64 from, u64 to); void tracing_start_cmdline_record(void); void tracing_stop_cmdline_record(void); diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c index 398195397c75..e56df2c7d679 100644 --- a/kernel/trace/trace_hw_branches.c +++ b/kernel/trace/trace_hw_branches.c @@ -40,6 +40,7 @@ static DEFINE_PER_CPU(unsigned char[SIZEOF_BTS], buffer); #define this_buffer per_cpu(buffer, smp_processor_id()) static int __read_mostly trace_hw_branches_enabled; +static struct trace_array *hw_branch_trace __read_mostly; /* @@ -128,6 +129,8 @@ static struct notifier_block bts_hotcpu_notifier __cpuinitdata = { static int bts_trace_init(struct trace_array *tr) { + hw_branch_trace = tr; + register_hotcpu_notifier(&bts_hotcpu_notifier); tracing_reset_online_cpus(tr); bts_trace_start(tr); @@ -170,8 +173,9 @@ static enum print_line_t bts_trace_print_line(struct trace_iterator *iter) return TRACE_TYPE_UNHANDLED; } -void trace_hw_branch(struct trace_array *tr, u64 from, u64 to) +void trace_hw_branch(u64 from, u64 to) { + struct trace_array *tr = hw_branch_trace; struct ring_buffer_event *event; struct hw_branch_entry *entry; unsigned long irq1, irq2; @@ -204,8 +208,7 @@ void trace_hw_branch(struct trace_array *tr, u64 from, u64 to) local_irq_restore(irq1); } -static void trace_bts_at(struct trace_array *tr, - const struct bts_trace *trace, void *at) +static void trace_bts_at(const struct bts_trace *trace, void *at) { struct bts_struct bts; int err = 0; @@ -220,7 +223,7 @@ static void trace_bts_at(struct trace_array *tr, switch (bts.qualifier) { case BTS_BRANCH: - trace_hw_branch(tr, bts.variant.lbr.from, bts.variant.lbr.to); + trace_hw_branch(bts.variant.lbr.from, bts.variant.lbr.to); break; } } @@ -236,12 +239,15 @@ static void trace_bts_cpu(void *arg) const struct bts_trace *trace; unsigned char *at; - if (!this_tracer) + if (unlikely(!tr)) return; if (unlikely(atomic_read(&tr->data[raw_smp_processor_id()]->disabled))) return; + if (unlikely(!this_tracer)) + return; + ds_suspend_bts(this_tracer); trace = ds_read_bts(this_tracer); if (!trace) @@ -249,11 +255,11 @@ static void trace_bts_cpu(void *arg) for (at = trace->ds.top; (void *)at < trace->ds.end; at += trace->ds.size) - trace_bts_at(tr, trace, at); + trace_bts_at(trace, at); for (at = trace->ds.begin; (void *)at < trace->ds.top; at += trace->ds.size) - trace_bts_at(tr, trace, at); + trace_bts_at(trace, at); out: ds_resume_bts(this_tracer); @@ -268,6 +274,15 @@ static void trace_bts_prepare(struct trace_iterator *iter) mutex_unlock(&bts_tracer_mutex); } +void trace_hw_branch_oops(void) +{ + mutex_lock(&bts_tracer_mutex); + + trace_bts_cpu(hw_branch_trace); + + mutex_unlock(&bts_tracer_mutex); +} + struct tracer bts_tracer __read_mostly = { .name = "hw-branch-tracer", |