| From 41bf85e23b59d1d42635df8ae0129869b61073d7 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Tue, 6 Apr 2021 12:16:01 -0400 |
| Subject: powerpc/perf: Fix PMU constraint check for EBB events |
| |
| From: Athira Rajeev <atrajeev@linux.vnet.ibm.com> |
| |
| [ Upstream commit 10f8f96179ecc7f69c927f6d231f6d02736cea83 ] |
| |
| The power PMU group constraints includes check for EBB events to make |
| sure all events in a group must agree on EBB. This will prevent |
| scheduling EBB and non-EBB events together. But in the existing check, |
| settings for constraint mask and value is interchanged. Patch fixes the |
| same. |
| |
| Before the patch, PMU selftest "cpu_event_pinned_vs_ebb_test" fails with |
| below in dmesg logs. This happens because EBB event gets enabled along |
| with a non-EBB cpu event. |
| |
| [35600.453346] cpu_event_pinne[41326]: illegal instruction (4) |
| at 10004a18 nip 10004a18 lr 100049f8 code 1 in |
| cpu_event_pinned_vs_ebb_test[10000000+10000] |
| |
| Test results after the patch: |
| |
| $ ./pmu/ebb/cpu_event_pinned_vs_ebb_test |
| test: cpu_event_pinned_vs_ebb |
| tags: git_version:v5.12-rc5-93-gf28c3125acd3-dirty |
| Binding to cpu 8 |
| EBB Handler is at 0x100050c8 |
| read error on event 0x7fffe6bd4040! |
| PM_RUN_INST_CMPL: result 9872 running/enabled 37930432 |
| success: cpu_event_pinned_vs_ebb |
| |
| This bug was hidden by other logic until commit 1908dc911792 (perf: |
| Tweak perf_event_attr::exclusive semantics). |
| |
| Fixes: 4df489991182 ("powerpc/perf: Add power8 EBB support") |
| Reported-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> |
| Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> |
| [mpe: Mention commit 1908dc911792] |
| Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
| Link: https://lore.kernel.org/r/1617725761-1464-1-git-send-email-atrajeev@linux.vnet.ibm.com |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| arch/powerpc/perf/isa207-common.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c |
| index 6ab5b272090a..58448f0e4721 100644 |
| --- a/arch/powerpc/perf/isa207-common.c |
| +++ b/arch/powerpc/perf/isa207-common.c |
| @@ -400,8 +400,8 @@ ebb_bhrb: |
| * EBB events are pinned & exclusive, so this should never actually |
| * hit, but we leave it as a fallback in case. |
| */ |
| - mask |= CNST_EBB_VAL(ebb); |
| - value |= CNST_EBB_MASK; |
| + mask |= CNST_EBB_MASK; |
| + value |= CNST_EBB_VAL(ebb); |
| |
| *maskp = mask; |
| *valp = value; |
| -- |
| 2.30.2 |
| |