From: Kajol Jain kjain@linux.ibm.com
[ Upstream commit 505d31650ba96d6032313480fdb566d289a4698c ]
Thresh compare bits for a event is used to program thresh compare field in Monitor Mode Control Register A (MMCRA: 8-18 bits for power10). When scheduling events as a group, all events in that group should match value in threshold bits. Otherwise event open for the sibling events should fail. But in the current code, incase thresh compare bits are not valid, we are not failing in group_constraint function which can result in invalid group schduling.
Fix the issue by returning -1 incase event is threshold and threshold compare value is not valid in group_constraint function.
Patch also fixes the p10_thresh_cmp_val function to return -1, incase threshold bits are not valid and changes corresponding check in is_thresh_cmp_valid function to return false only when the thresh_cmp value is less then 0.
Thresh control bits in the event code is used to program thresh_ctl field in Monitor Mode Control Register A (MMCRA: 48-55). In below example, the scheduling of group events PM_MRK_INST_CMPL (3534401e0) and PM_THRESH_MET (34340101ec) is expected to fail as both event request different thresh control bits.
Result before the patch changes:
[command]# perf stat -e "{r35340401e0,r34340101ec}" sleep 1
Performance counter stats for 'sleep 1':
8,482 r35340401e0 0 r34340101ec
1.001474838 seconds time elapsed
0.001145000 seconds user 0.000000000 seconds sys
Result after the patch changes:
[command]# perf stat -e "{r35340401e0,r34340101ec}" sleep 1
Performance counter stats for 'sleep 1':
<not counted> r35340401e0 <not supported> r34340101ec
1.001499607 seconds time elapsed
0.000204000 seconds user 0.000760000 seconds sys
Fixes: 82d2c16b350f7 ("powerpc/perf: Adds support for programming of Thresholding in P10") Signed-off-by: Kajol Jain kjain@linux.ibm.com Reviewed-by: Athira Rajeev atrajeev@linux.vnet.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20220506061015.43916-1-kjain@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/perf/isa207-common.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c index f92bf5f6b74f..b910a5a5d209 100644 --- a/arch/powerpc/perf/isa207-common.c +++ b/arch/powerpc/perf/isa207-common.c @@ -108,7 +108,7 @@ static void mmcra_sdar_mode(u64 event, unsigned long *mmcra) *mmcra |= MMCRA_SDAR_MODE_TLB; }
-static u64 p10_thresh_cmp_val(u64 value) +static int p10_thresh_cmp_val(u64 value) { int exp = 0; u64 result = value; @@ -139,7 +139,7 @@ static u64 p10_thresh_cmp_val(u64 value) * exponent is also zero. */ if (!(value & 0xC0) && exp) - result = 0; + result = -1; else result = (exp << 8) | value; } @@ -187,7 +187,7 @@ static bool is_thresh_cmp_valid(u64 event) unsigned int cmp, exp;
if (cpu_has_feature(CPU_FTR_ARCH_31)) - return p10_thresh_cmp_val(event) != 0; + return p10_thresh_cmp_val(event) >= 0;
/* * Check the mantissa upper two bits are not zero, unless the @@ -456,7 +456,8 @@ int isa207_get_constraint(u64 event, unsigned long *maskp, unsigned long *valp, value |= CNST_THRESH_CTL_SEL_VAL(event >> EVENT_THRESH_SHIFT); mask |= p10_CNST_THRESH_CMP_MASK; value |= p10_CNST_THRESH_CMP_VAL(p10_thresh_cmp_val(event_config1)); - } + } else if (event_is_threshold(event)) + return -1; } else if (cpu_has_feature(CPU_FTR_ARCH_300)) { if (event_is_threshold(event) && is_thresh_cmp_valid(event)) { mask |= CNST_THRESH_MASK;