powerpc/perf: Fix thresholding counter data for unknown type

MMCRA[34:36] and MMCRA[38:44] expose the thresholding counter value.
Thresholding counter can be used to count latency cycles such as
load miss to reload. But threshold counter value is not relevant
when the sampled instruction type is unknown or reserved. Patch to
fix the thresholding counter value to zero when sampled instruction
type is unknown or reserved.

Fixes: 170a315f('powerpc/perf: Support to export MMCRA[TEC*] field to userspace')
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/perf/isa207-common.c

@@ -226,7 +226,12 @@ void isa207_get_mem_weight(u64 *weight)
 	u64 mmcra = mfspr(SPRN_MMCRA);
 	u64 exp = MMCRA_THR_CTR_EXP(mmcra);
 	u64 mantissa = MMCRA_THR_CTR_MANT(mmcra);
+	u64 sier = mfspr(SPRN_SIER);
+	u64 val = (sier & ISA207_SIER_TYPE_MASK) >> ISA207_SIER_TYPE_SHIFT;
 
+	if (val == 0 || val == 7)
+		*weight = 0;
+	else
 		*weight = mantissa << (2 * exp);
 }