[PATCH] perf: Support for Arm A32/T32 instruction sets in CoreSight trace
From: Robert Walker
Date: Wed Aug 22 2018 - 12:04:45 EST
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 0.9.1 of OpenCSD. A check for the new struct
member has been added to the feature check for OpenCSD.
Signed-off-by: Robert Walker <robert.walker@xxxxxxx>
---
tools/build/feature/test-libopencsd.c | 7 +++
tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 27 ++++++++++
tools/perf/util/cs-etm-decoder/cs-etm-decoder.h | 10 ++++
tools/perf/util/cs-etm.c | 71 +++++++++++--------------
4 files changed, 75 insertions(+), 40 deletions(-)
diff --git a/tools/build/feature/test-libopencsd.c b/tools/build/feature/test-libopencsd.c
index 5ff1246..d96b2df 100644
--- a/tools/build/feature/test-libopencsd.c
+++ b/tools/build/feature/test-libopencsd.c
@@ -3,6 +3,13 @@
int main(void)
{
+ /*
+ * Requires ocsd_generic_trace_elem.num_instr_range introduced in
+ * OpenCSD 0.9
+ */
+ ocsd_generic_trace_elem elem;
+ (void)elem.num_instr_range;
+
(void)ocsd_get_version();
return 0;
}
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 938def6..73d8384 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 +297,13 @@ 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;
if (decoder->packet_count == MAX_BUFFER - 1)
return OCSD_RESP_WAIT;
@@ -321,8 +326,28 @@ 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 +361,8 @@ 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 612b575..9a10eda 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;
+ u64 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 2ae6402..579f52a 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;
@@ -492,21 +484,16 @@ 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];
- /*
- * 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).
+ cs_etm__mem_access(etmq, addr, 2, instrBytes);
+ /* 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)
@@ -518,27 +505,32 @@ 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)
@@ -867,9 +859,8 @@ 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;
/*
@@ -899,7 +890,7 @@ 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);
--
2.7.4