perf dlfilter: Add attr() to perf_dlfilter_fns

Add a function, for use by dlfilters, to return the perf_event_attr
structure.
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/20210627131818.810-10-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-dlfilter.txt

@@ -126,7 +126,8 @@ struct perf_dlfilter_fns {
 	__s32 (*resolve_address)(void *ctx, __u64 address, struct perf_dlfilter_al *al);
 	const __u8 *(*insn)(void *ctx, __u32 *length);
 	const char *(*srcline)(void *ctx, __u32 *line_number);
-	void *(*reserved[122])(void *);
+	struct perf_event_attr *(*attr)(void *ctx);
+	void *(*reserved[121])(void *);
 };
 ----
 
@@ -143,6 +144,8 @@ before calling. Returns 0 on success, -1 otherwise.
 
 'srcline' return source file name and line number.
 
+'attr' returns perf_event_attr, refer <linux/perf_event.h>.
+
 The perf_dlfilter_al structure
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

tools/perf/util/dlfilter.c

@@ -235,6 +235,16 @@ static const char *dlfilter__srcline(void *ctx, __u32 *line_no)
 	return srcfile;
 }
 
+static struct perf_event_attr *dlfilter__attr(void *ctx)
+{
+	struct dlfilter *d = (struct dlfilter *)ctx;
+
+	if (!d->ctx_valid)
+		return NULL;
+
+	return &d->evsel->core.attr;
+}
+
 static const struct perf_dlfilter_fns perf_dlfilter_fns = {
 	.resolve_ip      = dlfilter__resolve_ip,
 	.resolve_addr    = dlfilter__resolve_addr,
@@ -242,6 +252,7 @@ static const struct perf_dlfilter_fns perf_dlfilter_fns = {
 	.resolve_address = dlfilter__resolve_address,
 	.insn            = dlfilter__insn,
 	.srcline         = dlfilter__srcline,
+	.attr            = dlfilter__attr,
 };
 
 static char *find_dlfilter(const char *file)

tools/perf/util/perf_dlfilter.h

@@ -101,8 +101,10 @@ struct perf_dlfilter_fns {
 	const __u8 *(*insn)(void *ctx, __u32 *length);
 	/* Return source file name and line number */
 	const char *(*srcline)(void *ctx, __u32 *line_number);
+	/* Return perf_event_attr, refer <linux/perf_event.h> */
+	struct perf_event_attr *(*attr)(void *ctx);
 	/* Reserved */
-	void *(*reserved[122])(void *);
+	void *(*reserved[121])(void *);
 };
 
 /*