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.vn... 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;