4.4-stable review patch. If anyone has any objections, please let me know.
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From: "David S. Miller" davem@davemloft.net
[ 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 davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/sparc/kernel/perf_event.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)
--- 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 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
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(stru
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->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_eve 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,