linux/tools
Lexi Shao 1a86f4ba5c perf symbols: Ignore $a/$d symbols for ARM modules
On anARM machine, kernel symbols from modules can be resolved to $a
instead of printing the actual symbol name. Ignore symbols starting with
"$" when building kallsyms rbtree.

A sample stacktrace is shown as follows:

  c0f2e39c schedule_hrtimeout+0x14 ([kernel.kallsyms])
  bf4a66d8 $a+0x78 ([test_module])
  c0a4f5f4 kthread+0x15c ([kernel.kallsyms])
  c0a001f8 ret_from_fork+0x14 ([kernel.kallsyms])

On an ARM machine, $a/$d symbols are used by the compiler to mark the
beginning of code/data part in code section. These symbols are filtered
out when linking vmlinux(see scripts/kallsyms.c ignored_prefixes), but
are left on modules. So there are $a symbols in /proc/kallsyms which
share the same addresses with the actual module symbols and confuses
perf when resolving symbols.

After this patch, the module symbol name is printed:

  c0f2e39c schedule_hrtimeout+0x14 ([kernel.kallsyms])
  bf4a66d8 test_func+0x78 ([test_module])
  c0a4f5f4 kthread+0x15c ([kernel.kallsyms])
  c0a001f8 ret_from_fork+0x14 ([kernel.kallsyms])

Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Lexi Shao <shaolexi@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: QiuXi <qiuxi1@huawei.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Wangbing <wangbing6@huawei.com>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
Link: https://lore.kernel.org/r/20211029065038.39449-2-shaolexi@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-11-07 12:27:38 -03:00
..
accounting
arch Merge remote-tracking branch 'torvalds/master' into perf/core 2021-11-06 15:49:33 -03:00
bootconfig bootconfig: Cleanup dummy headers in tools/bootconfig 2021-10-10 22:16:02 -04:00
bpf bpftool: Switch to libbpf's hashmap for PIDs/names references 2021-10-25 17:31:39 -07:00
build tools: Bump minimum LLVM C++ std to GNU++14 2021-11-04 09:31:30 -03:00
cgroup
counter tools/counter: Create Counter tools 2021-10-17 10:54:16 +01:00
debugging tools: Fix "the the" in a message in kernel-chktaint 2021-06-13 17:01:17 -06:00
edid
firewire
firmware
gpio
hv
iio
include Merge remote-tracking branch 'torvalds/master' into perf/core 2021-11-06 15:49:33 -03:00
io_uring tools/io_uring/io_uring-cp: sync with liburing example 2021-08-13 08:58:11 -06:00
kvm/kvm_stat KVM: kvm_stat: do not show halt_wait_ns 2021-10-18 14:07:18 -04:00
laptop
leds
lib Merge remote-tracking branch 'torvalds/master' into perf/core 2021-11-06 15:49:33 -03:00
memory-model tools/memory-model: Document data_race(READ_ONCE()) 2021-07-27 11:48:55 -07:00
objtool Tracing updates for 5.16: 2021-11-01 20:05:19 -07:00
pci tools: PCI: Zero-initialize param 2021-08-05 11:01:30 +01:00
pcmcia
perf perf symbols: Ignore $a/$d symbols for ARM modules 2021-11-07 12:27:38 -03:00
power tools/power/x86/intel-speed-select: v1.10 release 2021-06-18 15:29:32 +02:00
rcu tools/rcu: Add an extract-stall script 2021-09-16 10:31:26 -07:00
scripts tools, build: Add RISC-V to HOSTARCH parsing 2021-11-01 17:08:21 +01:00
spi
testing powerpc updates for 5.16 2021-11-05 08:15:46 -07:00
thermal/tmon tools/thermal/tmon: Add cross compiling support 2021-08-14 15:33:19 +02:00
time
tracing tools/latency-collector: Use correct size when writing queue_full_warning 2021-10-25 22:27:19 -04:00
usb usb: testusb: Fix for showing the connection speed 2021-09-14 10:31:41 +02:00
virtio tools/virtio: fix build 2021-08-11 06:44:24 -04:00
vm tools/vm/page-types: remove dependency on opt_file for idle page tracking 2021-09-24 16:13:35 -07:00
wmi
Makefile tools/counter: Create Counter tools 2021-10-17 10:54:16 +01:00