The following commit has been merged into the perf/core branch of tip:
Commit-ID: 548e1f6c76e1eb80ba29edd4286b9b9f2c37f5bf
Gitweb:
https://git.kernel.org/tip/548e1f6c76e1eb80ba29edd4286b9b9f2c37f5bf
Author: Adrian Hunter <[email protected]>
AuthorDate: Tue, 12 May 2020 15:19:15 +03:00
Committer: Peter Zijlstra <[email protected]>
CommitterDate: Mon, 15 Jun 2020 14:09:50 +02:00
ftrace: Add perf text poke events for ftrace trampolines
Add perf text poke events for ftrace trampolines when created and when
freed.
There can be 3 text_poke events for ftrace trampolines:
1. NULL -> trampoline
By ftrace_update_trampoline() when !ops->trampoline
Trampoline created
2. [e.g. on x86] CALL rel32 -> CALL rel32
By arch_ftrace_update_trampoline() when ops->trampoline and
ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP
[e.g. on x86] via text_poke_bp() which generates text poke events
Trampoline-called function target updated
3. trampoline -> NULL
By ftrace_trampoline_free() when ops->trampoline and
ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP
Trampoline freed
Signed-off-by: Adrian Hunter <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
kernel/trace/ftrace.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 2baaf77..d6bba73 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2791,6 +2791,13 @@ static void ftrace_trampoline_free(struct ftrace_ops
*ops)
{
if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
ops->trampoline) {
+ /*
+ * Record the text poke event before the ksymbol unregister
+ * event.
+ */
+ perf_event_text_poke((void *)ops->trampoline,
+ (void *)ops->trampoline,
+ ops->trampoline_size, NULL, 0);
perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
ops->trampoline, ops->trampoline_size,
true, FTRACE_TRAMPOLINE_SYM);
@@ -6816,6 +6823,13 @@ static void ftrace_update_trampoline(struct ftrace_ops
*ops)
perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
ops->trampoline, ops->trampoline_size, false,
FTRACE_TRAMPOLINE_SYM);
+ /*
+ * Record the perf text poke event after the ksymbol register
+ * event.
+ */
+ perf_event_text_poke((void *)ops->trampoline, NULL, 0,
+ (void *)ops->trampoline,
+ ops->trampoline_size);
}
}
