From 1e032f7cfa141b4424827b0ecb0ea899f84e182e Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 15 May 2019 14:39:05 +0900 Subject: perf-probe: Add user memory access attribute support Add user memory access attribute for kprobe event arguments. If a given 'local variable' is in user-space, User can specify memory access method by '@user' suffix. This is not only for string but also for data structure. If we access a field of data structure in user memory from kernel on some arch, it will fail. e.g. perf probe -a "sched_setscheduler param->sched_priority" This will fail to access the "param->sched_priority" because the param is __user pointer. Instead, we can now specify @user suffix for such argument. perf probe -a "sched_setscheduler param->sched_priority@user" Note that kernel memory access with "@user" must always fail on any arch. Link: http://lkml.kernel.org/r/155789874562.26965.10836126971405890891.stgit@devnote2 Acked-by: Ingo Molnar Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- tools/perf/util/probe-file.h | 1 + 1 file changed, 1 insertion(+) (limited to 'tools/perf/util/probe-file.h') diff --git a/tools/perf/util/probe-file.h b/tools/perf/util/probe-file.h index 2a249182f2a6..986c1c94f64f 100644 --- a/tools/perf/util/probe-file.h +++ b/tools/perf/util/probe-file.h @@ -70,6 +70,7 @@ int probe_cache__show_all_caches(struct strfilter *filter); bool probe_type_is_available(enum probe_type type); bool kretprobe_offset_is_supported(void); bool uprobe_ref_ctr_is_supported(void); +bool user_access_is_supported(void); #else /* ! HAVE_LIBELF_SUPPORT */ static inline struct probe_cache *probe_cache__new(const char *tgt __maybe_unused, struct nsinfo *nsi __maybe_unused) { -- cgit v1.2.3-58-ga151