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Date: Fri, 8 Aug 2014 13:40:07 -0700 From: Kamal Mostafa <kamal@...onical.com> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org, kernel-team@...ts.ubuntu.com Cc: Michael Ellerman <mpe@...erman.id.au>, Benjamin Herrenschmidt <benh@...nel.crashing.org>, Kamal Mostafa <kamal@...onical.com> Subject: [PATCH 3.13 184/259] powerpc/perf: Fix MMCR2 handling for EBB 3.13.11.6 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Ellerman <mpe@...erman.id.au> commit 8903461c9bc56fcb041fb92d054e2529951770b6 upstream. In the recent commit b50a6c584bb4 "Clear MMCR2 when enabling PMU", I screwed up the handling of MMCR2 for tasks using EBB. We must make sure we set MMCR2 *before* ebb_switch_in(), otherwise we overwrite the value of MMCR2 that userspace may have written. That potentially breaks a task that uses EBB and manually uses MMCR2 for event freezing. Fixes: b50a6c584bb4 ("powerpc/perf: Clear MMCR2 when enabling PMU") Signed-off-by: Michael Ellerman <mpe@...erman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@...nel.crashing.org> Signed-off-by: Kamal Mostafa <kamal@...onical.com> --- arch/powerpc/perf/core-book3s.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index 57a8ff9..36a8bdd 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -1159,14 +1159,14 @@ static void power_pmu_enable(struct pmu *pmu) cpuhw->mmcr[0] |= MMCR0_PMXE | MMCR0_FCECE; out_enable: + if (ppmu->flags & PPMU_ARCH_207S) + mtspr(SPRN_MMCR2, 0); + mmcr0 = ebb_switch_in(ebb, cpuhw->mmcr[0]); mb(); write_mmcr0(cpuhw, mmcr0); - if (ppmu->flags & PPMU_ARCH_207S) - mtspr(SPRN_MMCR2, 0); - /* * Enable instruction sampling if necessary */ -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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