From 4c04e74c69338140164425abe9cd97394de9f356 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Fri, 12 Oct 2018 10:31:58 -0700 Subject: [PATCH] sparc: Fix single-pcr perf event counter management. [ Upstream commit cfdc3170d214046b9509183fe9b9544dc644d40b ] It is important to clear the hw->state value for non-stopped events when they are added into the PMU. Otherwise when the event is scheduled out, we won't read the counter because HES_UPTODATE is still set. This breaks 'perf stat' and similar use cases, causing all the events to show zero. This worked for multi-pcr because we make explicit sparc_pmu_start() calls in calculate_multiple_pcrs(). calculate_single_pcr() doesn't do this because the idea there is to accumulate all of the counter settings into the single pcr value. So we have to add explicit hw->state handling there. Like x86, we use the PERF_HES_ARCH bit to track truly stopped events so that we don't accidently start them on a reload. Related to all of this, sparc_pmu_start() is missing a userpage update so add it. Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/sparc/kernel/perf_event.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c index 710f327..71e7f77 100644 --- a/arch/sparc/kernel/perf_event.c +++ b/arch/sparc/kernel/perf_event.c @@ -926,6 +926,8 @@ static void read_in_all_counters(struct cpu_hw_events *cpuc) sparc_perf_event_update(cp, &cp->hw, cpuc->current_idx[i]); cpuc->current_idx[i] = PIC_NO_INDEX; + if (cp->hw.state & PERF_HES_STOPPED) + cp->hw.state |= PERF_HES_ARCH; } } } @@ -958,10 +960,12 @@ static void calculate_single_pcr(struct cpu_hw_events *cpuc) enc = perf_event_get_enc(cpuc->events[i]); cpuc->pcr[0] &= ~mask_for_index(idx); - if (hwc->state & PERF_HES_STOPPED) + if (hwc->state & PERF_HES_ARCH) { cpuc->pcr[0] |= nop_for_index(idx); - else + } else { cpuc->pcr[0] |= event_encoding(enc, idx); + hwc->state = 0; + } } out: cpuc->pcr[0] |= cpuc->event[0]->hw.config_base; @@ -987,6 +991,9 @@ static void calculate_multiple_pcrs(struct cpu_hw_events *cpuc) cpuc->current_idx[i] = idx; + if (cp->hw.state & PERF_HES_ARCH) + continue; + sparc_pmu_start(cp, PERF_EF_RELOAD); } out: @@ -1078,6 +1085,8 @@ static void sparc_pmu_start(struct perf_event *event, int flags) event->hw.state = 0; sparc_pmu_enable_event(cpuc, &event->hw, idx); + + perf_event_update_userpage(event); } static void sparc_pmu_stop(struct perf_event *event, int flags) @@ -1370,9 +1379,9 @@ static int sparc_pmu_add(struct perf_event *event, int ef_flags) cpuc->events[n0] = event->hw.event_base; cpuc->current_idx[n0] = PIC_NO_INDEX; - event->hw.state = PERF_HES_UPTODATE; + event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED; if (!(ef_flags & PERF_EF_START)) - event->hw.state |= PERF_HES_STOPPED; + event->hw.state |= PERF_HES_ARCH; /* * If group events scheduling transaction was started, -- 2.7.4