perf intel-pt/bts: Tidy instruction buffer size usage

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 <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/intel-bts.c

···
 	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;
···
 	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;
 

tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.c

···
 
 #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)
···
 	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;
 }
 
···
 		break;
 	}
 	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)

tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.h

···
 #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,
···
 	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,
···
 
 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);
 

tools/perf/util/intel-pt-decoder/intel-pt-log.c

···
 	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);

tools/perf/util/intel-pt.c

···
 	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;
···
 
 	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;
···
 
 		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;