Messages in this thread Patch in this message | | | From | Adrian Hunter <> | Subject | [PATCH V7 08/15] ftrace: Add perf text poke events for ftrace trampolines | Date | Tue, 12 May 2020 15:19:15 +0300 |
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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 <adrian.hunter@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- kernel/trace/ftrace.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1103a8fcf142..abdf8f415a6e 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2802,6 +2802,13 @@ 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); @@ -6826,6 +6833,13 @@ 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); } } -- 2.17.1
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