[PATCH V3 1/3] perf intel-pt/bts: Tidy instruction buffer size usage

[Adrian Hunter]

Tidy instruction buffer size usage in preparation for copying the
instruction bytes onto samples.

The instruction buffer is presently used for debugging, so rename its size
macro from INTEL_PT_INSN_DBG_BUF_SZ to INTEL_PT_INSN_BUF_SZ, and use it
everywhere.

Note that the maximum instruction size is 15 which is a less efficient size
to copy than 16, which is why a separate buffer size is used.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
 tools/perf/util/intel-bts.c                              |  8 +++-----
 tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.c | 13 ++++++-------
 tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.h |  6 ++----
 tools/perf/util/intel-pt-decoder/intel-pt-log.c          |  4 ++--
 tools/perf/util/intel-pt.c                               |  8 +++-----
 5 files changed, 16 insertions(+), 23 deletions(-)

diff --git a/tools/perf/util/intel-bts.c b/tools/perf/util/intel-bts.c
index f545ec1e758a..8bc7fec817d7 100644
--- a/tools/perf/util/intel-bts.c
+++ b/tools/perf/util/intel-bts.c
@@ -319,15 +319,12 @@ static int intel_bts_get_next_insn(struct intel_bts_queue *btsq, u64 ip)
 	struct machine *machine = btsq->bts->machine;
 	struct thread *thread;
 	struct addr_location al;
-	unsigned char buf[1024];
-	size_t bufsz;
+	unsigned char buf[INTEL_PT_INSN_BUF_SZ];
 	ssize_t len;
 	int x86_64;
 	uint8_t cpumode;
 	int err = -1;
 
-	bufsz = intel_pt_insn_max_size();
-
 	if (machine__kernel_ip(machine, ip))
 		cpumode = PERF_RECORD_MISC_KERNEL;
 	else
@@ -341,7 +338,8 @@ static int intel_bts_get_next_insn(struct intel_bts_queue *btsq, u64 ip)
 	if (!al.map || !al.map->dso)
 		goto out_put;
 
-	len = dso__data_read_addr(al.map->dso, al.map, machine, ip, buf, bufsz);
+	len = dso__data_read_addr(al.map->dso, al.map, machine, ip, buf,
+				  INTEL_PT_INSN_BUF_SZ);
 	if (len <= 0)
 		goto out_put;
 
diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.c
index d23138c06665..5f95cd442075 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.c
@@ -27,6 +27,10 @@
 
 #include "intel-pt-insn-decoder.h"
 
+#if INTEL_PT_INSN_BUF_SZ < MAX_INSN_SIZE
+#error Instruction buffer size too small
+#endif
+
 /* Based on branch_type() from perf_event_intel_lbr.c */
 static void intel_pt_insn_decoder(struct insn *insn,
 				  struct intel_pt_insn *intel_pt_insn)
@@ -166,10 +170,10 @@ int intel_pt_get_insn(const unsigned char *buf, size_t len, int x86_64,
 	if (!insn_complete(&insn) || insn.length > len)
 		return -1;
 	intel_pt_insn_decoder(&insn, intel_pt_insn);
-	if (insn.length < INTEL_PT_INSN_DBG_BUF_SZ)
+	if (insn.length < INTEL_PT_INSN_BUF_SZ)
 		memcpy(intel_pt_insn->buf, buf, insn.length);
 	else
-		memcpy(intel_pt_insn->buf, buf, INTEL_PT_INSN_DBG_BUF_SZ);
+		memcpy(intel_pt_insn->buf, buf, INTEL_PT_INSN_BUF_SZ);
 	return 0;
 }
 
@@ -211,11 +215,6 @@ int intel_pt_insn_desc(const struct intel_pt_insn *intel_pt_insn, char *buf,
 	return 0;
 }
 
-size_t intel_pt_insn_max_size(void)
-{
-	return MAX_INSN_SIZE;
-}
-
 int intel_pt_insn_type(enum intel_pt_insn_op op)
 {
 	switch (op) {
diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.h b/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.h
index b0adbf37323e..37ec5627ae9b 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.h
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.h
@@ -20,7 +20,7 @@
 #include <stdint.h>
 
 #define INTEL_PT_INSN_DESC_MAX		32
-#define INTEL_PT_INSN_DBG_BUF_SZ	16
+#define INTEL_PT_INSN_BUF_SZ		16
 
 enum intel_pt_insn_op {
 	INTEL_PT_OP_OTHER,
@@ -47,7 +47,7 @@ struct intel_pt_insn {
 	enum intel_pt_insn_branch	branch;
 	int				length;
 	int32_t				rel;
-	unsigned char			buf[INTEL_PT_INSN_DBG_BUF_SZ];
+	unsigned char			buf[INTEL_PT_INSN_BUF_SZ];
 };
 
 int intel_pt_get_insn(const unsigned char *buf, size_t len, int x86_64,
@@ -58,8 +58,6 @@ const char *intel_pt_insn_name(enum intel_pt_insn_op op);
 int intel_pt_insn_desc(const struct intel_pt_insn *intel_pt_insn, char *buf,
 		       size_t buf_len);
 
-size_t intel_pt_insn_max_size(void);
-
 int intel_pt_insn_type(enum intel_pt_insn_op op);
 
 #endif
diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-log.c b/tools/perf/util/intel-pt-decoder/intel-pt-log.c
index 319bef33a64b..e02bc7b166a0 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-log.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-log.c
@@ -119,8 +119,8 @@ void __intel_pt_log_insn(struct intel_pt_insn *intel_pt_insn, uint64_t ip)
 	if (intel_pt_log_open())
 		return;
 
-	if (len > INTEL_PT_INSN_DBG_BUF_SZ)
-		len = INTEL_PT_INSN_DBG_BUF_SZ;
+	if (len > INTEL_PT_INSN_BUF_SZ)
+		len = INTEL_PT_INSN_BUF_SZ;
 	intel_pt_print_data(intel_pt_insn->buf, len, ip, 8);
 	if (intel_pt_insn_desc(intel_pt_insn, desc, INTEL_PT_INSN_DESC_MAX) > 0)
 		fprintf(f, "%s\n", desc);
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index dc041d4368c8..815a14d8904b 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -428,8 +428,7 @@ static int intel_pt_walk_next_insn(struct intel_pt_insn *intel_pt_insn,
 	struct machine *machine = ptq->pt->machine;
 	struct thread *thread;
 	struct addr_location al;
-	unsigned char buf[1024];
-	size_t bufsz;
+	unsigned char buf[INTEL_PT_INSN_BUF_SZ];
 	ssize_t len;
 	int x86_64;
 	u8 cpumode;
@@ -440,8 +439,6 @@ static int intel_pt_walk_next_insn(struct intel_pt_insn *intel_pt_insn,
 	if (to_ip && *ip == to_ip)
 		goto out_no_cache;
 
-	bufsz = intel_pt_insn_max_size();
-
 	if (*ip >= ptq->pt->kernel_start)
 		cpumode = PERF_RECORD_MISC_KERNEL;
 	else
@@ -493,7 +490,8 @@ static int intel_pt_walk_next_insn(struct intel_pt_insn *intel_pt_insn,
 
 		while (1) {
 			len = dso__data_read_offset(al.map->dso, machine,
-						    offset, buf, bufsz);
+						    offset, buf,
+						    INTEL_PT_INSN_BUF_SZ);
 			if (len <= 0)
 				return -EINVAL;
 
-- 
1.9.1