From 548e1f6c76e1eb80ba29edd4286b9b9f2c37f5bf Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Tue, 12 May 2020 15:19:15 +0300 Subject: [PATCH] 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 Signed-off-by: Peter Zijlstra (Intel) Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200512121922.8997-9-adrian.hunter@intel.com --- 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); } } -- 2.7.4