powerpc/perf: Drop the check for SIAR_VALID

In power10 DD1, there is an issue that causes the SIAR_VALID bit of
the SIER (Sampled Instruction Event Register) to not be set. But the
SIAR_VALID bit is used for fetching the instruction address from the
SIAR (Sampled Instruction Address Register), and marked events are
sampled only if the SIAR_VALID bit is set. So drop the check for
SIAR_VALID and return true always incase of power10 DD1.
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201021085329.384535-2-maddy@linux.ibm.com

arch/powerpc/perf/core-book3s.c

@@ -350,7 +350,14 @@ static inline int siar_valid(struct pt_regs *regs)
 	int marked = mmcra & MMCRA_SAMPLE_ENABLE;
 
 	if (marked) {
-		if (ppmu->flags & PPMU_HAS_SIER)
+		/*
+		 * SIER[SIAR_VALID] is not set for some
+		 * marked events on power10 DD1, so drop
+		 * the check for SIER[SIAR_VALID] and return true.
+		 */
+		if (ppmu->flags & PPMU_P10_DD1)
+			return 0x1;
+		else if (ppmu->flags & PPMU_HAS_SIER)
 			return regs->dar & SIER_SIAR_VALID;
 
 		if (ppmu->flags & PPMU_SIAR_VALID)