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| author | Stephane Eranian <eranian@google.com> | 2012-08-24 13:34:34 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-08-27 06:48:19 (GMT) |
| commit | e3e45c01ae690e65f2650e5288b9af802e95a136 (patch) | |
| tree | 8a1032f058653b75bd0d4c975e93e1c4316a44db /arch | |
| parent | 9acb172543aecb783e2e1e53e3f447d4c0f5c150 (diff) | |
| download | linux-e3e45c01ae690e65f2650e5288b9af802e95a136.tar.xz | |
perf/x86: Fix microcode revision check for SNB-PEBS
The following patch makes the microcode update code path
actually invoke the perf_check_microcode() function and
thus potentially renabling SNB PEBS.
By default, CONFIG_MICROCODE_OLD_INTERFACE is
forced to Y in arch/x86/Kconfig. There is no
way to disable this. That means that the code
path used in arch/x86/kernel/microcode_core.c
did not include the call to perf_check_microcode().
Thus, even though the microcode was updated to a
version that fixes the SNB PEBS problem, perf_event
would still return EOPNOTSUPP when enabling precise
sampling.
This patch simply adds a call to perf_check_microcode()
in the call path used when OLD_INTERFACE=y.
Signed-off-by: Stephane Eranian <eranian@google.com>
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: peterz@infradead.org
Cc: andi@firstfloor.org
Link: http://lkml.kernel.org/r/20120824133434.GA8014@quad
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/microcode_core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c index 4873e62..9e5bcf1 100644 --- a/arch/x86/kernel/microcode_core.c +++ b/arch/x86/kernel/microcode_core.c @@ -225,6 +225,9 @@ static ssize_t microcode_write(struct file *file, const char __user *buf, if (do_microcode_update(buf, len) == 0) ret = (ssize_t)len; + if (ret > 0) + perf_check_microcode(); + mutex_unlock(µcode_mutex); put_online_cpus(); |