Unverified Commit ea687311 authored by Pu Lehui's avatar Pu Lehui Committed by Palmer Dabbelt
Browse files

drivers/perf: riscv: Disable PERF_SAMPLE_BRANCH_* while not supported 

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: f5bfa23f ("RISC-V: Add a perf core library for pmu drivers")
Signed-off-by: default avatarPu Lehui <pulehui@huawei.com>
Reviewed-by: default avatarAtish Patra <atishp@rivosinc.com>
Reviewed-by: default avatarConor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240312012053.1178140-1-pulehui@huaweicloud.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 4b0bf9a0

drivers/perf/riscv_pmu.c

+4 −0
Original line number Diff line number Diff line
@@ -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) {