6.8-stable review patch. If anyone has any objections, please let me know.
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From: Pu Lehui pulehui@huawei.com
[ Upstream commit ea6873118493019474abbf57d5a800da365734df ]
RISC-V perf driver does not yet support branch sampling. Although the specification is in the works [0], it is best to disable such events until support is available, otherwise we will get unexpected results. Due to this reason, two riscv bpf testcases get_branch_snapshot and perf_branches/perf_branches_hw fail.
Link: https://github.com/riscv/riscv-control-transfer-records [0] Fixes: f5bfa23f576f ("RISC-V: Add a perf core library for pmu drivers") Signed-off-by: Pu Lehui pulehui@huawei.com Reviewed-by: Atish Patra atishp@rivosinc.com Reviewed-by: Conor Dooley conor.dooley@microchip.com Link: https://lore.kernel.org/r/20240312012053.1178140-1-pulehui@huaweicloud.com Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/perf/riscv_pmu.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/perf/riscv_pmu.c b/drivers/perf/riscv_pmu.c index c78a6fd6c57f6..b4efdddb2ad91 100644 --- a/drivers/perf/riscv_pmu.c +++ b/drivers/perf/riscv_pmu.c @@ -313,6 +313,10 @@ static int riscv_pmu_event_init(struct perf_event *event) u64 event_config = 0; uint64_t cmask;
+ /* driver does not support branch stack sampling */ + if (has_branch_stack(event)) + return -EOPNOTSUPP; + hwc->flags = 0; mapped_event = rvpmu->event_map(event, &event_config); if (mapped_event < 0) {