From 82715a0f332843d3a1830d7ebc9ac7c99a00c880 Mon Sep 17 00:00:00 2001
From: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Date: Wed, 26 Aug 2020 02:40:29 -0400
Subject: [PATCH] powerpc/perf: Fix reading of MSR[HV/PR] bits in trace-imc
References: jsc#SLE-13513
Patch-mainline: v5.9-rc3
Git-commit: 82715a0f332843d3a1830d7ebc9ac7c99a00c880
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: 77ca3951cc37 ("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
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/perf/imc-pmu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
index a45d694a5d5d..62d0b54086f8 100644
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/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;
--
2.28.0