6.6-stable review patch. If anyone has any objections, please let me know.
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From: Matt Bobrowski mattbobrowski@google.com
[ Upstream commit 27746aaf1b20172f0859546c4a3e82eca459f680 ]
Gracefully skip the test_perf_branches_hw subtest on platforms that do not support LBR or require specialized perf event attributes to enable branch sampling.
For example, AMD's Milan (Zen 3) supports BRS rather than traditional LBR. This requires specific configurations (attr.type = PERF_TYPE_RAW, attr.config = RETIRED_TAKEN_BRANCH_INSTRUCTIONS) that differ from the generic setup used within this test. Notably, it also probably doesn't hold much value to special case perf event configurations for selected micro architectures.
Fixes: 67306f84ca78c ("selftests/bpf: Add bpf_read_branch_records() selftest") Signed-off-by: Matt Bobrowski mattbobrowski@google.com Acked-by: Song Liu song@kernel.org Link: https://lore.kernel.org/r/20251120142059.2836181-1-mattbobrowski@google.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/testing/selftests/bpf/prog_tests/perf_branches.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/perf_branches.c b/tools/testing/selftests/bpf/prog_tests/perf_branches.c index bc24f83339d64..06c7986131d96 100644 --- a/tools/testing/selftests/bpf/prog_tests/perf_branches.c +++ b/tools/testing/selftests/bpf/prog_tests/perf_branches.c @@ -116,11 +116,11 @@ static void test_perf_branches_hw(void) pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
/* - * Some setups don't support branch records (virtual machines, !x86), - * so skip test in this case. + * Some setups don't support LBR (virtual machines, !x86, AMD Milan Zen + * 3 which only supports BRS), so skip test in this case. */ if (pfd < 0) { - if (errno == ENOENT || errno == EOPNOTSUPP) { + if (errno == ENOENT || errno == EOPNOTSUPP || errno == EINVAL) { printf("%s:SKIP:no PERF_SAMPLE_BRANCH_STACK\n", __func__); test__skip();