Subject: [PATCH v2 09/10] tools/perf: Add perf tools support for extended register capability in powerpc

From: Athira Rajeev <[email-masked]>
Date: Wed, 1 Jul 2020 05:21:01 -0400

From: Anju T Sudhakar <[email-masked]>

Add extended regs to sample_reg_mask in the tool side to use
with `-I?` option. Perf tools side uses extended mask to display
the platform supported register names (with -I? option) to the user
and also send this mask to the kernel to capture the extended registers
in each sample. Hence decide the mask value based on the processor
version.

Signed-off-by: Anju T Sudhakar <[email-masked]>
[Decide extended mask at run time based on platform]
Signed-off-by: Athira Rajeev <[email-masked]>
Reviewed-by: Madhavan Srinivasan <[email-masked]>
---
 tools/arch/powerpc/include/uapi/asm/perf_regs.h | 14 ++++++-
 tools/perf/arch/powerpc/include/perf_regs.h     |  5 ++-
 tools/perf/arch/powerpc/util/perf_regs.c        | 55 +++++++++++++++++++++++++
 3 files changed, 72 insertions(+), 2 deletions(-)

diff --git a/tools/arch/powerpc/include/uapi/asm/perf_regs.h b/tools/arch/powerpc/include/uapi/asm/perf_regs.h
index f599064..485b1d5 100644
--- a/tools/arch/powerpc/include/uapi/asm/perf_regs.h
+++ b/tools/arch/powerpc/include/uapi/asm/perf_regs.h
@@ -48,6 +48,18 @@ enum perf_event_powerpc_regs {
 	PERF_REG_POWERPC_DSISR,
 	PERF_REG_POWERPC_SIER,
 	PERF_REG_POWERPC_MMCRA,
-	PERF_REG_POWERPC_MAX,
+	/* Extended registers */
+	PERF_REG_POWERPC_MMCR0,
+	PERF_REG_POWERPC_MMCR1,
+	PERF_REG_POWERPC_MMCR2,
+	/* Max regs without the extended regs */
+	PERF_REG_POWERPC_MAX = PERF_REG_POWERPC_MMCRA + 1,
 };
+
+#define PERF_REG_PMU_MASK	((1ULL << PERF_REG_POWERPC_MAX) - 1)
+
+/* PERF_REG_EXTENDED_MASK value for CPU_FTR_ARCH_300 */
+#define PERF_REG_PMU_MASK_300   (((1ULL << (PERF_REG_POWERPC_MMCR2 + 1)) - 1) \
+				- PERF_REG_PMU_MASK)
+
 #endif /* _UAPI_ASM_POWERPC_PERF_REGS_H */
diff --git a/tools/perf/arch/powerpc/include/perf_regs.h b/tools/perf/arch/powerpc/include/perf_regs.h
index e18a355..46ed00d 100644
--- a/tools/perf/arch/powerpc/include/perf_regs.h
+++ b/tools/perf/arch/powerpc/include/perf_regs.h
@@ -64,7 +64,10 @@
 	[PERF_REG_POWERPC_DAR] = "dar",
 	[PERF_REG_POWERPC_DSISR] = "dsisr",
 	[PERF_REG_POWERPC_SIER] = "sier",
-	[PERF_REG_POWERPC_MMCRA] = "mmcra"
+	[PERF_REG_POWERPC_MMCRA] = "mmcra",
+	[PERF_REG_POWERPC_MMCR0] = "mmcr0",
+	[PERF_REG_POWERPC_MMCR1] = "mmcr1",
+	[PERF_REG_POWERPC_MMCR2] = "mmcr2",
 };
 
 static inline const char *perf_reg_name(int id)
diff --git a/tools/perf/arch/powerpc/util/perf_regs.c b/tools/perf/arch/powerpc/util/perf_regs.c
index 0a52429..9179230 100644
--- a/tools/perf/arch/powerpc/util/perf_regs.c
+++ b/tools/perf/arch/powerpc/util/perf_regs.c
@@ -6,9 +6,14 @@
 
 #include "../../../util/perf_regs.h"
 #include "../../../util/debug.h"
+#include "../../../util/event.h"
+#include "../../../util/header.h"
+#include "../../../perf-sys.h"
 
 #include <linux/kernel.h>
 
+#define PVR_POWER9		0x004E
+
 const struct sample_reg sample_reg_masks[] = {
 	SMPL_REG(r0, PERF_REG_POWERPC_R0),
 	SMPL_REG(r1, PERF_REG_POWERPC_R1),
@@ -55,6 +60,9 @@
 	SMPL_REG(dsisr, PERF_REG_POWERPC_DSISR),
 	SMPL_REG(sier, PERF_REG_POWERPC_SIER),
 	SMPL_REG(mmcra, PERF_REG_POWERPC_MMCRA),
+	SMPL_REG(mmcr0, PERF_REG_POWERPC_MMCR0),
+	SMPL_REG(mmcr1, PERF_REG_POWERPC_MMCR1),
+	SMPL_REG(mmcr2, PERF_REG_POWERPC_MMCR2),
 	SMPL_REG_END
 };
 
@@ -163,3 +171,50 @@ int arch_sdt_arg_parse_op(char *old_op, char **new_op)
 
 	return SDT_ARG_VALID;
 }
+
+uint64_t arch__intr_reg_mask(void)
+{
+	struct perf_event_attr attr = {
+		.type                   = PERF_TYPE_HARDWARE,
+		.config                 = PERF_COUNT_HW_CPU_CYCLES,
+		.sample_type            = PERF_SAMPLE_REGS_INTR,
+		.precise_ip             = 1,
+		.disabled               = 1,
+		.exclude_kernel         = 1,
+	};
+	int fd, ret;
+	char buffer[64];
+	u32 version;
+	u64 extended_mask = 0;
+
+	/* Get the PVR value to set the extended
+	 * mask specific to platform
+	 */
+	get_cpuid(buffer, sizeof(buffer));
+	ret = sscanf(buffer, "%u,", &version);
+
+	if (ret != 1) {
+		pr_debug("Failed to get the processor version, unable to output extended registers\n");
+		return PERF_REGS_MASK;
+	}
+
+	if (version == PVR_POWER9)
+		extended_mask = PERF_REG_PMU_MASK_300;
+	else
+		return PERF_REGS_MASK;
+
+	attr.sample_regs_intr = extended_mask;
+	attr.sample_period = 1;
+	event_attr_init(&attr);
+
+	/*
+	 * check if the pmu supports perf extended regs, before
+	 * returning the register mask to sample.
+	 */
+	fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
+	if (fd != -1) {
+		close(fd);
+		return (extended_mask | PERF_REGS_MASK);
+	}
+	return PERF_REGS_MASK;
+}
-- 
1.8.3.1