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| author | Masami Hiramatsu <mhiramat@kernel.org> | 2019-05-15 14:39:05 +0900 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2019-05-25 23:04:42 -0400 |
| commit | 1e032f7cfa141b4424827b0ecb0ea899f84e182e (patch) | |
| tree | 929053b3dc3a806529788e54d9700f556b48911b /tools/perf/util/probe-file.c | |
| parent | bdf2b8cbf076568f7d17dc62467348d409142298 (diff) | |
| download | lwn-1e032f7cfa141b4424827b0ecb0ea899f84e182e.tar.gz lwn-1e032f7cfa141b4424827b0ecb0ea899f84e182e.zip | |
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 <mingo@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'tools/perf/util/probe-file.c')
| -rw-r--r-- | tools/perf/util/probe-file.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c index 4062bc4412a9..89ce1a9c3798 100644 --- a/tools/perf/util/probe-file.c +++ b/tools/perf/util/probe-file.c @@ -1015,6 +1015,7 @@ enum ftrace_readme { FTRACE_README_PROBE_TYPE_X = 0, FTRACE_README_KRETPROBE_OFFSET, FTRACE_README_UPROBE_REF_CTR, + FTRACE_README_USER_ACCESS, FTRACE_README_END, }; @@ -1027,6 +1028,7 @@ static struct { DEFINE_TYPE(FTRACE_README_PROBE_TYPE_X, "*type: * x8/16/32/64,*"), DEFINE_TYPE(FTRACE_README_KRETPROBE_OFFSET, "*place (kretprobe): *"), DEFINE_TYPE(FTRACE_README_UPROBE_REF_CTR, "*ref_ctr_offset*"), + DEFINE_TYPE(FTRACE_README_USER_ACCESS, "*[u]<offset>*"), }; static bool scan_ftrace_readme(enum ftrace_readme type) @@ -1087,3 +1089,8 @@ bool uprobe_ref_ctr_is_supported(void) { return scan_ftrace_readme(FTRACE_README_UPROBE_REF_CTR); } + +bool user_access_is_supported(void) +{ + return scan_ftrace_readme(FTRACE_README_USER_ACCESS); +} |