Hi, Here is a couple of patches to enable debuginfod support on perf probe command. This allows users to access debuginfo binary from remote device.
Since the perf-probe heavily depends on the debuginfo, debuginfod gives us many benefits on the perf probe command on remote machine, especially for the embedded devices. Here is an example (copied from [2/2]) 1. at first you need to start debuginfod on the host machine. -F option scans local debuginfo binary. (You don't need to pass the source tree, but you must keep the source tree untouched) (host) $ cd PATH/TO/KBUILD/DIR/ (host) $ debuginfod -F . ... 2. In the remote machine, you need to set DEBUGINFOD_URLS. debuginfod uses 8002 tcp port. (remote) # export DEBUGINFOD_URLS="http://$HOST_IP:8002/"; 3. Then you can use the perf probe (it can refer the source code) (remote) # perf probe -L vfs_read <vfs_read@...> 0 ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) { 2 ssize_t ret; if (!(file->f_mode & FMODE_READ)) return -EBADF; 6 if (!(file->f_mode & FMODE_CAN_READ)) return -EINVAL; 8 if (unlikely(!access_ok(buf, count))) return -EFAULT; 11 ret = rw_verify_area(READ, file, pos, count); 12 if (ret) return ret; if (count > MAX_RW_COUNT) ... (remote) # perf probe -a "vfs_read count" Added new event: probe:vfs_read (on vfs_read with count) (remote) # perf probe -l probe:vfs_read (on vfs_read@ksrc/linux/fs/read_write.c with count) Thank you, --- Masami Hiramatsu (2): perf probe: Fix to adjust symbol address with correct reloc_sym address perf probe: Fall back to debuginfod query if debuginfo and source not found tools/perf/util/probe-event.c | 60 +++++++++++++++++++++++++++++++++++++--- tools/perf/util/probe-finder.c | 56 ++++++++++++++++++++++++++++++++++--- tools/perf/util/probe-finder.h | 7 +++-- 3 files changed, 112 insertions(+), 11 deletions(-) -- Masami Hiramatsu (Linaro) <mhira...@kernel.org>
