From: Pu Lehui <pulehui@huaweicloud.com>
To: linux-riscv@lists.infradead.org, bpf@vger.kernel.org
Cc: "Atish Patra" <atishp@atishpatra.org>,
"Conor Dooley" <conor@kernel.org>,
"Anup Patel" <anup@brainfault.org>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
"Björn Töpel" <bjorn@kernel.org>, "Pu Lehui" <pulehui@huawei.com>,
"Pu Lehui" <pulehui@huaweicloud.com>
Subject: [PATCH v2] drivers/perf: riscv: Disable PERF_SAMPLE_BRANCH_* while not supported
Date: Tue, 12 Mar 2024 01:20:53 +0000 [thread overview]
Message-ID: <20240312012053.1178140-1-pulehui@huaweicloud.com> (raw)
From: Pu Lehui <pulehui@huawei.com>
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>
---
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 c78a6fd6c57f..b4efdddb2ad9 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) {
--
2.34.1
next reply other threads:[~2024-03-12 1:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-12 1:20 Pu Lehui [this message]
2024-03-12 12:52 ` [PATCH v2] drivers/perf: riscv: Disable PERF_SAMPLE_BRANCH_* while not supported Conor Dooley
2024-03-12 19:12 ` Atish Patra
2024-03-27 14:00 ` patchwork-bot+linux-riscv
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