[ 3.5.y.z extended stable ] Patch "sparc64: Fix bit twiddling in sparc_pmu_enable_event()." has been added to staging queue

[Herton Ronaldo Krzesinski]

This is a note to let you know that I have just added a patch titled

    sparc64: Fix bit twiddling in sparc_pmu_enable_event().

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

>From bb842de60c67703d45e1d05c9cbef179d4bd626d Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem at davemloft.net>
Date: Tue, 16 Oct 2012 13:05:25 -0700
Subject: [PATCH] sparc64: Fix bit twiddling in sparc_pmu_enable_event().

commit e793d8c6740f8fe704fa216e95685f4d92c4c4b9 upstream.

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 at davemloft.net>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 arch/sparc/kernel/perf_event.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index b0cce26..ac18037 100644
--- 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);
--
1.7.9.5