Re: [PATCH V3 2/2] tools/perf: Add perf tools support for extended register capability in powerpc

From: Madhavan Srinivasan
Date: Tue May 26 2020 - 03:29:41 EST




On 5/20/20 3:15 PM, Athira Rajeev wrote:
From: Anju T Sudhakar <anju@xxxxxxxxxxxxxxxxxx>

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 <anju@xxxxxxxxxxxxxxxxxx>
[Decide extended mask at run time based on platform]
Signed-off-by: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>

Reviewed-by: Madhavan Srinivasan <maddy@xxxxxxxxxxxxx>

---
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;
+}