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Subject[ 39/42] sparc64: Fix bit twiddling in sparc_pmu_enable_event().
Date
3.4-stable review patch.  If anyone has any objections, please let me know.

------------------


From: "David S. Miller" <davem@davemloft.net>

[ Upstream commit e793d8c6740f8fe704fa216e95685f4d92c4c4b9 ]

There was a serious disconnect in the logic happening in
sparc_pmu_disable_event() vs. sparc_pmu_enable_event().

Event disable is implemented by programming a NOP event into the PCR.

However, event enable was not reversing this operation. Instead, it
was setting the User/Priv/Hypervisor trace enable bits.

That's not sparc_pmu_enable_event()'s job, that's what
sparc_pmu_enable() and sparc_pmu_disable() do .

The intent of sparc_pmu_enable_event() is clear, since it first clear
out the event type encoding field. So fix this by OR'ing in the event
encoding rather than the trace enable bits.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/sparc/kernel/perf_event.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -557,11 +557,13 @@ static u64 nop_for_index(int idx)

static inline void sparc_pmu_enable_event(struct cpu_hw_events *cpuc, struct hw_perf_event *hwc, int idx)
{
- u64 val, mask = mask_for_index(idx);
+ u64 enc, val, mask = mask_for_index(idx);
+
+ enc = perf_event_get_enc(cpuc->events[idx]);

val = cpuc->pcr;
val &= ~mask;
- val |= hwc->config;
+ val |= event_encoding(enc, idx);
cpuc->pcr = val;

pcr_ops->write(cpuc->pcr);



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