powerpc/perf: Use MSR to report privilege level on P9 DD1

SIER and SIAR are not updated correctly for some samples, so force the
use of MSR and regs->nip instead for misc_flag updates. This is done by
adding a new ppmu flag and updating the use_siar logic in
perf_read_regs() to use it, and dropping the PPMU_HAS_SIER flag.

Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
[mpe: Rename flag to PPMU_NO_SIAR, and also drop PPMU_HAS_SIER]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/perf_event_server.h

@@ -65,6 +65,7 @@ struct power_pmu {
 #define PPMU_HAS_SSLOT		0x00000020 /* Has sampled slot in MMCRA */
 #define PPMU_HAS_SIER		0x00000040 /* Has SIER */
 #define PPMU_ARCH_207S		0x00000080 /* PMC is architecture v2.07S */
+#define PPMU_NO_SIAR		0x00000100 /* Do not use SIAR */
 
 /*
  * Values for flags to get_alternatives()

arch/powerpc/perf/core-book3s.c

@@ -295,6 +295,8 @@ static inline void perf_read_regs(struct pt_regs *regs)
 	 */
 	if (TRAP(regs) != 0xf00)
 		use_siar = 0;
+	else if ((ppmu->flags & PPMU_NO_SIAR))
+		use_siar = 0;
 	else if (marked)
 		use_siar = 1;
 	else if ((ppmu->flags & PPMU_NO_CONT_SAMPLING))

arch/powerpc/perf/power9-pmu.c

@@ -384,7 +384,7 @@ static struct power_pmu power9_isa207_pmu = {
 	.bhrb_filter_map	= power9_bhrb_filter_map,
 	.get_constraint		= isa207_get_constraint,
 	.disable_pmc		= isa207_disable_pmc,
-	.flags			= PPMU_HAS_SIER | PPMU_ARCH_207S,
+	.flags			= PPMU_NO_SIAR | PPMU_ARCH_207S,
 	.n_generic		= ARRAY_SIZE(power9_generic_events),
 	.generic_events		= power9_generic_events,
 	.cache_events		= &power9_cache_events,