From b1862199be6098855b598b69f5098d2fb4cecfcb Mon Sep 17 00:00:00 2001 From: "Suzuki K. Poulose" Date: Tue, 17 Mar 2015 18:15:00 +0000 Subject: drivers: cci: reject groups spanning multiple HW PMUs The perf core implicitly rejects events spanning multiple HW PMUs, as in these cases the event->ctx will differ. However this validation is performed after pmu::event_init() is called in perf_init_event(), and thus pmu::event_init() may be called with a group leader from a different HW PMU. The CCI PMU driver does not take this fact into account, and assumes that the any other hardware event belongs to the CCI. There are two issues with it : 1) It is wrong and we should reject such groups. 2) Validation allocates an temporary idx for this non-cci event, which leads to wrong calculation of the counter availability, and eventually lesser number of events in the group. This patch updates the CCI PMU driver to first test for and reject events from other PMUs, which is the right thing to do. Cc: Will Deacon Acked-by: Mark Rutland Acked-by: Peter Ziljstra (Intel) Signed-off-by: Suzuki K. Poulose Signed-off-by: Will Deacon --- drivers/bus/arm-cci.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) (limited to 'drivers/bus/arm-cci.c') diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c index 84fd66057dad..68ef6f2aa24d 100644 --- a/drivers/bus/arm-cci.c +++ b/drivers/bus/arm-cci.c @@ -660,12 +660,21 @@ static void cci_pmu_del(struct perf_event *event, int flags) } static int -validate_event(struct cci_pmu_hw_events *hw_events, - struct perf_event *event) +validate_event(struct pmu *cci_pmu, + struct cci_pmu_hw_events *hw_events, + struct perf_event *event) { if (is_software_event(event)) return 1; + /* + * Reject groups spanning multiple HW PMUs (e.g. CPU + CCI). The + * core perf code won't check that the pmu->ctx == leader->ctx + * until after pmu->event_init(event). + */ + if (event->pmu != cci_pmu) + return 0; + if (event->state < PERF_EVENT_STATE_OFF) return 1; @@ -687,15 +696,15 @@ validate_group(struct perf_event *event) .used_mask = CPU_BITS_NONE, }; - if (!validate_event(&fake_pmu, leader)) + if (!validate_event(event->pmu, &fake_pmu, leader)) return -EINVAL; list_for_each_entry(sibling, &leader->sibling_list, group_entry) { - if (!validate_event(&fake_pmu, sibling)) + if (!validate_event(event->pmu, &fake_pmu, sibling)) return -EINVAL; } - if (!validate_event(&fake_pmu, event)) + if (!validate_event(event->pmu, &fake_pmu, event)) return -EINVAL; return 0; -- cgit v1.2.3