perf dlfilter: Add insn() to perf_dlfilter_fns

Add a function, for use by dlfilters, to return instruction bytes.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210627131818.810-8-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Author: ahunter6

tools/perf/Documentation/perf-dlfilter.txt

@@ -124,7 +124,8 @@ struct perf_dlfilter_fns {
 	const struct perf_dlfilter_al *(*resolve_addr)(void *ctx);
 	char **(*args)(void *ctx, int *dlargc);
 	__s32 (*resolve_address)(void *ctx, __u64 address, struct perf_dlfilter_al *al);
-	void *(*reserved[124])(void *);
+	const __u8 *(*insn)(void *ctx, __u32 *length);
+	void *(*reserved[123])(void *);
 };
 ----
 
@@ -137,6 +138,8 @@ struct perf_dlfilter_fns {
 'resolve_address' provides information about 'address'. al->size must be set
 before calling. Returns 0 on success, -1 otherwise.
 
+'insn' returns instruction bytes and length.
+
 The perf_dlfilter_al structure
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

tools/perf/util/dlfilter.c

@@ -17,6 +17,7 @@
 #include "dso.h"
 #include "map.h"
 #include "thread.h"
+#include "trace-event.h"
 #include "symbol.h"
 #include "dlfilter.h"
 #include "perf_dlfilter.h"
@@ -177,11 +178,42 @@ static __s32 dlfilter__resolve_address(void *ctx, __u64 address, struct perf_dlf
 	return 0;
 }
 
+static const __u8 *dlfilter__insn(void *ctx, __u32 *len)
+{
+	struct dlfilter *d = (struct dlfilter *)ctx;
+
+	if (!len)
+		return NULL;
+
+	*len = 0;
+
+	if (!d->ctx_valid)
+		return NULL;
+
+	if (d->sample->ip && !d->sample->insn_len) {
+		struct addr_location *al = d->al;
+
+		if (!al->thread && machine__resolve(d->machine, al, d->sample) < 0)
+			return NULL;
+
+		if (al->thread->maps && al->thread->maps->machine)
+			script_fetch_insn(d->sample, al->thread, al->thread->maps->machine);
+	}
+
+	if (!d->sample->insn_len)
+		return NULL;
+
+	*len = d->sample->insn_len;
+
+	return (__u8 *)d->sample->insn;
+}
+
 static const struct perf_dlfilter_fns perf_dlfilter_fns = {
 	.resolve_ip      = dlfilter__resolve_ip,
 	.resolve_addr    = dlfilter__resolve_addr,
 	.args            = dlfilter__args,
 	.resolve_address = dlfilter__resolve_address,
+	.insn            = dlfilter__insn,
 };
 
 static char *find_dlfilter(const char *file)

tools/perf/util/perf_dlfilter.h

@@ -97,8 +97,10 @@ struct perf_dlfilter_fns {
 	 * calling). Returns 0 on success, -1 otherwise.
 	 */
 	__s32 (*resolve_address)(void *ctx, __u64 address, struct perf_dlfilter_al *al);
+	/* Return instruction bytes and length */
+	const __u8 *(*insn)(void *ctx, __u32 *length);
 	/* Reserved */
-	void *(*reserved[124])(void *);
+	void *(*reserved[123])(void *);
 };
 
 /*