[ Upstream commit 9794563d4d053b1b46a0cc91901f0a11d8678c19 ]
Now that it's possible to capture LBR on AMD CPU from BPF at arbitrary point, there is no reason to artificially limit this feature to just sampling events. So corresponding check is removed. AFAIU, there is no correctness implications of doing this (and it was possible to bypass this check by just setting perf_event's sample_period to 1 anyways, so it doesn't guard all that much).
Signed-off-by: Andrii Nakryiko andrii@kernel.org Signed-off-by: Ingo Molnar mingo@kernel.org Reviewed-by: Sandipan Das sandipan.das@amd.com Link: https://lore.kernel.org/r/20240402022118.1046049-5-andrii@kernel.org Signed-off-by: Leon Hwang leon.hwang@linux.dev --- arch/x86/events/amd/lbr.c | 4 ---- 1 file changed, 4 deletions(-)
diff --git a/arch/x86/events/amd/lbr.c b/arch/x86/events/amd/lbr.c index 33d0a45c0cd3..19c7b76e21bc 100644 --- a/arch/x86/events/amd/lbr.c +++ b/arch/x86/events/amd/lbr.c @@ -310,10 +310,6 @@ int amd_pmu_lbr_hw_config(struct perf_event *event) { int ret = 0;
- /* LBR is not recommended in counting mode */ - if (!is_sampling_event(event)) - return -EINVAL; - ret = amd_pmu_lbr_setup_filter(event); if (!ret) event->attach_state |= PERF_ATTACH_SCHED_CB;