[PATCH v2] powerpc/perf: Add kernel support for new MSR[HV PR] bits in trace-imc

[PATCH v2] powerpc/perf: Add kernel support for new MSR[HV PR] bits in trace-imc

[Madhavan Srinivasan]

From: Anju T Sudhakar <anju@linux.vnet.ibm.com>

IMC trace-mode record has MSR[HV PR] bits added in the third DW.
These bits can be used to set the cpumode for the instruction pointer
captured in each sample.

Add support in kernel to use these bits to set the cpumode for
each sample.

Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com> 
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
---
Changelog v1:
- Changed check to use CPU_FTR_ARCH_31

 arch/powerpc/include/asm/imc-pmu.h |  5 +++++
 arch/powerpc/perf/imc-pmu.c        | 29 ++++++++++++++++++++++++-----
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/imc-pmu.h b/arch/powerpc/include/asm/imc-pmu.h
index 4da4fcba0684..4f897993b710 100644
--- a/arch/powerpc/include/asm/imc-pmu.h
+++ b/arch/powerpc/include/asm/imc-pmu.h
@@ -99,6 +99,11 @@ struct trace_imc_data {
  */
 #define IMC_TRACE_RECORD_TB1_MASK      0x3ffffffffffULL
 
+/*
+ * Bit 0:1 in third DW of IMC trace record
+ * specifies the MSR[HV PR] values.
+ */
+#define IMC_TRACE_RECORD_VAL_HVPR(x)	((x) >> 62)
 
 /*
  * Device tree parser code detects IMC pmu support and
diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
index 0edcfd0b491d..a45d694a5d5d 100644
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/arch/powerpc/perf/imc-pmu.c
@@ -1288,11 +1288,30 @@ static int trace_imc_prepare_sample(struct trace_imc_data *mem,
 	header->size = sizeof(*header) + event->header_size;
 	header->misc = 0;
 
-	if (is_kernel_addr(data->ip))
-		header->misc |= PERF_RECORD_MISC_KERNEL;
-	else
-		header->misc |= PERF_RECORD_MISC_USER;
-
+	if (cpu_has_feature(CPU_FTR_ARCH_31)) {
+		switch (IMC_TRACE_RECORD_VAL_HVPR(mem->val)) {
+		case 0:/* when MSR HV and PR not set in the trace-record */
+			header->misc |= PERF_RECORD_MISC_GUEST_KERNEL;
+			break;
+		case 1: /* MSR HV is 0 and PR is 1 */
+			header->misc |= PERF_RECORD_MISC_GUEST_USER;
+			break;
+		case 2: /* MSR HV is 1 and PR is 0 */
+			header->misc |= PERF_RECORD_MISC_HYPERVISOR;
+			break;
+		case 3: /* MSR HV is 1 and PR is 1 */
+			header->misc |= PERF_RECORD_MISC_USER;
+			break;
+		default:
+			pr_info("IMC: Unable to set the flag based on MSR bits\n");
+			break;
+		}
+	} else {
+		if (is_kernel_addr(data->ip))
+			header->misc |= PERF_RECORD_MISC_KERNEL;
+		else
+			header->misc |= PERF_RECORD_MISC_USER;
+	}
 	perf_event_header__init_id(header, data, event);
 
 	return 0;
-- 
2.26.2

Re: [PATCH v2] powerpc/perf: Add kernel support for new MSR[HV PR] bits in trace-imc

[Michael Ellerman]

On Mon, 13 Jul 2020 20:16:23 +0530, Madhavan Srinivasan wrote:
> IMC trace-mode record has MSR[HV PR] bits added in the third DW.
> These bits can be used to set the cpumode for the instruction pointer
> captured in each sample.
> 
> Add support in kernel to use these bits to set the cpumode for
> each sample.

Applied to powerpc/next.

[1/1] powerpc/perf: Add kernel support for new MSR[HV PR] bits in trace-imc
      https://git.kernel.org/powerpc/c/77ca3951cc37727ae8361d583a30da7a1b84e427

cheers