From dd9ddf466ad7a5d2e247925d81ebb0b878bf3b76 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Tue, 12 May 2020 15:19:14 +0300 Subject: [PATCH] ftrace: Add perf ksymbol events for ftrace trampolines Symbols are needed for tools to describe instruction addresses. Pages allocated for ftrace's purposes need symbols to be created for them. Add such symbols to be visible via perf ksymbol events. Signed-off-by: Adrian Hunter Signed-off-by: Peter Zijlstra (Intel) Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200512121922.8997-8-adrian.hunter@intel.com --- include/uapi/linux/perf_event.h | 2 +- kernel/trace/ftrace.c | 14 ++++++++++++-- 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index e1a4179144a13..52ca2093831cc 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -1051,7 +1051,7 @@ enum perf_record_ksymbol_type { PERF_RECORD_KSYMBOL_TYPE_BPF = 1, /* * Out of line code such as kprobe-replaced instructions or optimized - * kprobes. + * kprobes or ftrace trampolines. */ PERF_RECORD_KSYMBOL_TYPE_OOL = 2, PERF_RECORD_KSYMBOL_TYPE_MAX /* non-ABI */ diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 31675b209db2a..2baaf77165372 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2790,8 +2790,13 @@ static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops) static void ftrace_trampoline_free(struct ftrace_ops *ops) { if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) && - ops->trampoline) + ops->trampoline) { + perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, + ops->trampoline, ops->trampoline_size, + true, FTRACE_TRAMPOLINE_SYM); + /* Remove from kallsyms after the perf events */ ftrace_remove_trampoline_from_kallsyms(ops); + } arch_ftrace_trampoline_free(ops); } @@ -6805,8 +6810,13 @@ static void ftrace_update_trampoline(struct ftrace_ops *ops) arch_ftrace_update_trampoline(ops); if (ops->trampoline && ops->trampoline != trampoline && - (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) + (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) { + /* Add to kallsyms before the perf events */ ftrace_add_trampoline_to_kallsyms(ops); + perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, + ops->trampoline, ops->trampoline_size, false, + FTRACE_TRAMPOLINE_SYM); + } } void ftrace_init_trace_array(struct trace_array *tr) -- 2.30.2