[PATCH 35/75] perf cs-etm: Support for ARM A32/T32 instruction sets in CoreSight trace

Arnaldo Carvalho de Melo
2018-12-06T21:28:59Z

From: Robert Walker <robert.walker@arm.com>

This patch adds support for generating instruction samples from trace of
AArch32 programs using the A32 and T32 instruction sets.

T32 has variable 2 or 4 byte instruction size, so the conversion between
addresses and instruction counts requires extra information from the
trace decoder, requiring version 0.10.0 of OpenCSD. A check for the
OpenCSD library version has been added to the feature check for OpenCSD.

Signed-off-by: Robert Walker <robert.walker@arm.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1543839526-30348-1-git-send-email-robert.walker@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/build/feature/test-libopencsd.c | 8 +++
.../perf/util/cs-etm-decoder/cs-etm-decoder.c | 29 ++++++++
.../perf/util/cs-etm-decoder/cs-etm-decoder.h | 10 +++
tools/perf/util/cs-etm.c | 70 ++++++++-----------
4 files changed, 78 insertions(+), 39 deletions(-)

diff --git a/tools/build/feature/test-libopencsd.c b/tools/build/feature/test-libopencsd.c
index 5ff1246e6194..d68eb4fb40cc 100644
--- a/tools/build/feature/test-libopencsd.c
+++ b/tools/build/feature/test-libopencsd.c
@@ -1,6 +1,14 @@
// SPDX-License-Identifier: GPL-2.0
#include <opencsd/c_api/opencsd_c_api.h>

+/*
+ * Check OpenCSD library version is sufficient to provide required features
+ */
+#define OCSD_MIN_VER ((0 << 16) | (10 << 8) | (0))
+#if !defined(OCSD_VER_NUM) || (OCSD_VER_NUM < OCSD_MIN_VER)
+#error "OpenCSD >= 0.10.0 is required"
+#endif
+
int main(void)
{
(void)ocsd_get_version();
diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
index 938def6d0bb9..5efb616bd609 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
@@ -263,9 +263,12 @@ static void cs_etm_decoder__clear_buffer(struct cs_etm_decoder *decoder)
decoder->tail = 0;
decoder->packet_count = 0;
for (i = 0; i < MAX_BUFFER; i++) {
+ decoder->packet_buffer[i].isa = CS_ETM_ISA_UNKNOWN;
decoder->packet_buffer[i].start_addr = CS_ETM_INVAL_ADDR;
decoder->packet_buffer[i].end_addr = CS_ETM_INVAL_ADDR;
+ decoder->packet_buffer[i].instr_count = 0;
decoder->packet_buffer[i].last_instr_taken_branch = false;
+ decoder->packet_buffer[i].last_instr_size = 0;
decoder->packet_buffer[i].exc = false;
decoder->packet_buffer[i].exc_ret = false;
decoder->packet_buffer[i].cpu = INT_MIN;
@@ -294,11 +297,15 @@ cs_etm_decoder__buffer_packet(struct cs_etm_decoder *decoder,
decoder->packet_count++;

decoder->packet_buffer[et].sample_type = sample_type;
+ decoder->packet_buffer[et].isa = CS_ETM_ISA_UNKNOWN;
decoder->packet_buffer[et].exc = false;
decoder->packet_buffer[et].exc_ret = false;
decoder->packet_buffer[et].cpu = *((int *)inode->priv);
decoder->packet_buffer[et].start_addr = CS_ETM_INVAL_ADDR;
decoder->packet_buffer[et].end_addr = CS_ETM_INVAL_ADDR;
+ decoder->packet_buffer[et].instr_count = 0;
+ decoder->packet_buffer[et].last_instr_taken_branch = false;
+ decoder->packet_buffer[et].last_instr_size = 0;

if (decoder->packet_count == MAX_BUFFER - 1)
return OCSD_RESP_WAIT;
@@ -321,8 +328,28 @@ cs_etm_decoder__buffer_range(struct cs_etm_decoder *decoder,

packet = &decoder->packet_buffer[decoder->tail];

+ switch (elem->isa) {
+ case ocsd_isa_aarch64:
+ packet->isa = CS_ETM_ISA_A64;
+ break;
+ case ocsd_isa_arm:
+ packet->isa = CS_ETM_ISA_A32;
+ break;
+ case ocsd_isa_thumb2:
+ packet->isa = CS_ETM_ISA_T32;
+ break;
+ case ocsd_isa_tee:
+ case ocsd_isa_jazelle:
+ case ocsd_isa_custom:
+ case ocsd_isa_unknown:
+ default:
+ packet->isa = CS_ETM_ISA_UNKNOWN;
+ }
+
packet->start_addr = elem->st_addr;
packet->end_addr = elem->en_addr;
+ packet->instr_count = elem->num_instr_range;
+
switch (elem->last_i_type) {
case OCSD_INSTR_BR:
case OCSD_INSTR_BR_INDIRECT:
@@ -336,6 +363,8 @@ cs_etm_decoder__buffer_range(struct cs_etm_decoder *decoder,
break;
}

+ packet->last_instr_size = elem->last_instr_sz;
+
return ret;
}

diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
index 612b5755f742..9351bd10d864 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
@@ -28,11 +28,21 @@ enum cs_etm_sample_type {
CS_ETM_TRACE_ON = 1 << 1,
};

+enum cs_etm_isa {
+ CS_ETM_ISA_UNKNOWN,
+ CS_ETM_ISA_A64,
+ CS_ETM_ISA_A32,
+ CS_ETM_ISA_T32,
+};
+
struct cs_etm_packet {
enum cs_etm_sample_type sample_type;
+ enum cs_etm_isa isa;
u64 start_addr;
u64 end_addr;
+ u32 instr_count;
u8 last_instr_taken_branch;
+ u8 last_instr_size;
u8 exc;
u8 exc_ret;
int cpu;
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 73430b73570d..48ad217bf0df 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -31,14 +31,6 @@

#define MAX_TIMESTAMP (~0ULL)

-/*
- * A64 instructions are always 4 bytes
- *
- * Only A64 is supported, so can use this constant for converting between
- * addresses and instruction counts, calculting offsets etc
- */
-#define A64_INSTR_SIZE 4
-
struct cs_etm_auxtrace {
struct auxtrace auxtrace;
struct auxtrace_queues queues;
@@ -510,21 +502,17 @@ static inline void cs_etm__reset_last_branch_rb(struct cs_etm_queue *etmq)
etmq->last_branch_rb->nr = 0;
}

-static inline u64 cs_etm__last_executed_instr(struct cs_etm_packet *packet)
-{
- /* Returns 0 for the CS_ETM_TRACE_ON packet */
- if (packet->sample_type == CS_ETM_TRACE_ON)
- return 0;
+static inline int cs_etm__t32_instr_size(struct cs_etm_queue *etmq,
+ u64 addr) {
+ u8 instrBytes[2];

+ cs_etm__mem_access(etmq, addr, ARRAY_SIZE(instrBytes), instrBytes);
/*
- * The packet records the execution range with an exclusive end address
- *
- * A64 instructions are constant size, so the last executed
- * instruction is A64_INSTR_SIZE before the end address
- * Will need to do instruction level decode for T32 instructions as
- * they can be variable size (not yet supported).
+ * T32 instruction size is indicated by bits[15:11] of the first
+ * 16-bit word of the instruction: 0b11101, 0b11110 and 0b11111
+ * denote a 32-bit instruction.
*/
- return packet->end_addr - A64_INSTR_SIZE;
+ return ((instrBytes[1] & 0xF8) >= 0xE8) ? 4 : 2;
}

static inline u64 cs_etm__first_executed_instr(struct cs_etm_packet *packet)
@@ -536,27 +524,32 @@ static inline u64 cs_etm__first_executed_instr(struct cs_etm_packet *packet)
return packet->start_addr;
}

-static inline u64 cs_etm__instr_count(const struct cs_etm_packet *packet)
+static inline
+u64 cs_etm__last_executed_instr(const struct cs_etm_packet *packet)
{
- /*
- * Only A64 instructions are currently supported, so can get
- * instruction count by dividing.
- * Will need to do instruction level decode for T32 instructions as
- * they can be variable size (not yet supported).
- */
- return (packet->end_addr - packet->start_addr) / A64_INSTR_SIZE;
+ /* Returns 0 for the CS_ETM_TRACE_ON packet */
+ if (packet->sample_type == CS_ETM_TRACE_ON)
+ return 0;
+
+ return packet->end_addr - packet->last_instr_size;
}

-static inline u64 cs_etm__instr_addr(const struct cs_etm_packet *packet,
+static inline u64 cs_etm__instr_addr(struct cs_etm_queue *etmq,
+ const struct cs_etm_packet *packet,
u64 offset)
{
- /*
- * Only A64 instructions are currently supported, so can get
- * instruction address by muliplying.
- * Will need to do instruction level decode for T32 instructions as
- * they can be variable size (not yet supported).
- */
- return packet->start_addr + offset * A64_INSTR_SIZE;
+ if (packet->isa == CS_ETM_ISA_T32) {
+ u64 addr = packet->start_addr;
+
+ while (offset > 0) {
+ addr += cs_etm__t32_instr_size(etmq, addr);
+ offset--;
+ }
+ return addr;
+ }
+
+ /* Assume a 4 byte instruction size (A32/A64) */
+ return packet->start_addr + offset * 4;
}

static void cs_etm__update_last_branch_rb(struct cs_etm_queue *etmq)
@@ -888,9 +881,8 @@ static int cs_etm__sample(struct cs_etm_queue *etmq)
struct cs_etm_auxtrace *etm = etmq->etm;
struct cs_etm_packet *tmp;
int ret;
- u64 instrs_executed;
+ u64 instrs_executed = etmq->packet->instr_count;

- instrs_executed = cs_etm__instr_count(etmq->packet);
etmq->period_instructions += instrs_executed;

/*
@@ -920,7 +912,7 @@ static int cs_etm__sample(struct cs_etm_queue *etmq)
* executed, but PC has not advanced to next instruction)
*/
u64 offset = (instrs_executed - instrs_over - 1);
- u64 addr = cs_etm__instr_addr(etmq->packet, offset);
+ u64 addr = cs_etm__instr_addr(etmq, etmq->packet, offset);

ret = cs_etm__synth_instruction_sample(
etmq, addr, etm->instructions_sample_period);
--
2.19.2