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authorFrederic Weisbecker <fweisbec@gmail.com>2010-03-04 21:15:56 +0100
committerFrederic Weisbecker <fweisbec@gmail.com>2010-03-10 14:39:35 +0100
commit5331d7b84613b8325362dde53dc2bff2fb87d351 (patch)
tree60f4bf4fdaf31b612eefc291bf6b558dc4c8d947 /kernel
parent61e67fb9d3ed13e6a7f58652ae4979b9c872fa57 (diff)
perf: Introduce new perf_fetch_caller_regs() for hot regs snapshot
Events that trigger overflows by interrupting a context can use get_irq_regs() or task_pt_regs() to retrieve the state when the event triggered. But this is not the case for some other class of events like trace events as tracepoints are executed in the same context than the code that triggered the event. It means we need a different api to capture the regs there, namely we need a hot snapshot to get the most important informations for perf: the instruction pointer to get the event origin, the frame pointer for the callchain, the code segment for user_mode() tests (we always use __KERNEL_CS as trace events always occur from the kernel) and the eflags for further purposes. v2: rename perf_save_regs to perf_fetch_caller_regs as per Masami's suggestion. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Masami Hiramatsu <mhiramat@redhat.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Archs <linux-arch@vger.kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/perf_event.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 52c69a34d69..359d7f690c2 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -2786,6 +2786,11 @@ __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
return NULL;
}
+__weak
+void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip)
+{
+}
+
/*
* Output
*/