[PATCH v2 4/5] perf tools: Use machine->root_dir to find /proc/kallsyms

[Namhyung Kim <namhyung@kernel.org>]

This is for test functions to find the kallsyms correctly.  It can find
the machine from the kernel maps and use its root_dir.  This is helpful
to setup fake /proc directory for testing.

Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/util/symbol.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index b533fbf17a8b19a3..6ddbf4427c60dace 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -2002,6 +2002,7 @@ static char *dso__find_kallsyms(struct dso *dso, struct map *map)
 	char sbuild_id[SBUILD_ID_SIZE];
 	bool is_host = false;
 	char path[PATH_MAX];
+	struct maps *kmaps = map__kmaps(map);
 
 	if (!dso__has_build_id(dso)) {
 		/*
@@ -2038,8 +2039,13 @@ static char *dso__find_kallsyms(struct dso *dso, struct map *map)
 		return strdup(path);
 
 	/* Use current /proc/kallsyms if possible */
-	if (is_host) {
 proc_kallsyms:
+	if (kmaps) {
+		struct machine *machine = maps__machine(kmaps);
+
+		scnprintf(path, sizeof(path), "%s/proc/kallsyms", machine->root_dir);
+		return strdup(path);
+	} else if (is_host) {
 		return strdup("/proc/kallsyms");
 	}
 
-- 
2.52.0.158.g65b55ccf14-goog