Commit-ID: e3e45c01ae690e65f2650e5288b9af802e95a136 Gitweb: http://git.kernel.org/tip/e3e45c01ae690e65f2650e5288b9af802e95a136 Author: Stephane Eranian <eranian@xxxxxxxxxx> AuthorDate: Fri, 24 Aug 2012 15:34:34 +0200 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Mon, 27 Aug 2012 08:48:19 +0200 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@xxxxxxxxxx> Acked-by: Borislav Petkov <borislav.petkov@xxxxxxx> Cc: peterz@xxxxxxxxxxxxx Cc: andi@xxxxxxxxxxxxxx Link: http://lkml.kernel.org/r/20120824133434.GA8014@quad Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- 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(); -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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