[PATCH V3] powerpc/perf: Fix Threshold Event Counter Multiplier width for P10

From: Madhavan Srinivasan <maddy@linux.ibm.com>

Threshold Event Counter Multiplier (TECM) is part of Monitor Mode
Control Register A (MMCRA). This field along with Threshold Event
Counter Exponent (TECE) is used to get threshould counter value.
In Power10, this is a 8bit field, so patch fixes the
current code to modify the MMCRA[TECM] extraction macro to
handle this change. ISA v3.1 says this is a 7 bit field but
POWER10 it's actually 8 bits which will hopefully be fixed
in ISA v3.1 update.

Fixes: 170a315f41c64 ('powerpc/perf: Support to export MMCRA[TEC*] field to userspace')
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Athira Rajeev <redacted>
---
Changelog v2 -> v3:
- Since in POWER10 it's actually 8 bits which will hopefully be
  fixed in ISA3.1 update, bring back the cpu feature check which
  is the appropriate one.

Changelog v1 -> v2:
- Fixed the commit message
- Fixed the condition check to use PVR check for power10
  instead of ISA v3.1 cpu feature check.

 arch/powerpc/perf/isa207-common.c | 3 +++
 arch/powerpc/perf/isa207-common.h | 4 ++++
 2 files changed, 7 insertions(+)

diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c
index 24f0a90..6ab5b27 100644
--- a/arch/powerpc/perf/isa207-common.c
+++ b/arch/powerpc/perf/isa207-common.c

@@ -247,6 +247,9 @@ void isa207_get_mem_weight(u64 *weight)
 	u64 sier = mfspr(SPRN_SIER);
 	u64 val = (sier & ISA207_SIER_TYPE_MASK) >> ISA207_SIER_TYPE_SHIFT;
 
+	if (cpu_has_feature(CPU_FTR_ARCH_31))
+		mantissa = P10_MMCRA_THR_CTR_MANT(mmcra);
+
 	if (val == 0 || val == 7)
 		*weight = 0;
 	else

diff --git a/arch/powerpc/perf/isa207-common.h b/arch/powerpc/perf/isa207-common.h
index 4208764..454b32c 100644
--- a/arch/powerpc/perf/isa207-common.h
+++ b/arch/powerpc/perf/isa207-common.h

@@ -231,6 +231,10 @@
 #define MMCRA_THR_CTR_EXP(v)		(((v) >> MMCRA_THR_CTR_EXP_SHIFT) &\
 						MMCRA_THR_CTR_EXP_MASK)
 
+#define P10_MMCRA_THR_CTR_MANT_MASK	0xFFul
+#define P10_MMCRA_THR_CTR_MANT(v)	(((v) >> MMCRA_THR_CTR_MANT_SHIFT) &\
+						P10_MMCRA_THR_CTR_MANT_MASK)
+
 /* MMCRA Threshold Compare bit constant for power9 */
 #define p9_MMCRA_THR_CMP_SHIFT	45
 

-- 
1.8.3.1

On Tue, 15 Dec 2020 03:56:18 -0500, Athira Rajeev wrote:

Threshold Event Counter Multiplier (TECM) is part of Monitor Mode
Control Register A (MMCRA). This field along with Threshold Event
Counter Exponent (TECE) is used to get threshould counter value.
In Power10, this is a 8bit field, so patch fixes the
current code to modify the MMCRA[TECM] extraction macro to
handle this change. ISA v3.1 says this is a 7 bit field but
POWER10 it's actually 8 bits which will hopefully be fixed
in ISA v3.1 update.

Applied to powerpc/next.

[1/1] powerpc/perf: Fix Threshold Event Counter Multiplier width for P10
      https://git.kernel.org/powerpc/c/ef0e3b650f8ddc54bb70868852f50642ee3ae765

cheers