powerpc/perf: Fix reading of MSR[HV/PR] bits in trace-imc

IMC trace-mode uses MSR[HV/PR] bits to set the cpumode for the
instruction pointer captured in each sample. The bits are fetched from
the third double word of the trace record. Reading third double word
from IMC trace record should use be64_to_cpu() along with READ_ONCE
inorder to fetch correct MSR[HV/PR] bits. Patch addresses this change.

Currently we are using PERF_RECORD_MISC_HYPERVISOR as cpumode if MSR
HV is 1 and PR is 0 which means the address is from host counter. But
using PERF_RECORD_MISC_HYPERVISOR for host counter data will fail to
resolve the address -> symbol during "perf report" because perf tools
side uses PERF_RECORD_MISC_KERNEL to represent the host counter data.
Therefore, fix the trace imc sample data to use
PERF_RECORD_MISC_KERNEL as cpumode for host kernel information.

Fixes: 77ca3951 ("powerpc/perf: Add kernel support for new MSR[HV PR] bits in trace-imc")
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1598424029-1662-1-git-send-email-atrajeev@linux.vnet.ibm.com

arch/powerpc/perf/imc-pmu.c

@@ -1289,7 +1289,7 @@ static int trace_imc_prepare_sample(struct trace_imc_data *mem,
 	header->misc = 0;
 
 	if (cpu_has_feature(CPU_FTR_ARCH_31)) {
-		switch (IMC_TRACE_RECORD_VAL_HVPR(mem->val)) {
+		switch (IMC_TRACE_RECORD_VAL_HVPR(be64_to_cpu(READ_ONCE(mem->val)))) {
 		case 0:/* when MSR HV and PR not set in the trace-record */
 			header->misc |= PERF_RECORD_MISC_GUEST_KERNEL;
 			break;
@@ -1297,7 +1297,7 @@ static int trace_imc_prepare_sample(struct trace_imc_data *mem,
 			header->misc |= PERF_RECORD_MISC_GUEST_USER;
 			break;
 		case 2: /* MSR HV is 1 and PR is 0 */
-			header->misc |= PERF_RECORD_MISC_HYPERVISOR;
+			header->misc |= PERF_RECORD_MISC_KERNEL;
 			break;
 		case 3: /* MSR HV is 1 and PR is 1 */
 			header->misc |= PERF_RECORD_MISC_USER;