[PATCH 1/2] perf: support specify vdso path in cmdline

[Changbin Du]

The vdso dumped from process memory (in buildid-cache) lacks debugging
info. To annotate vdso symbols with source lines we need specify a
debugging version.

For x86, we can find them from your local build as
arch/x86/entry/vdso/vdso{32,64}.so.dbg. Or they may reside in
/lib/modules/<version>/vdso/vdso{32,64}.so on Ubuntu. But notice that
the buildid has to match.

$ sudo perf record -a
$ sudo perf report --objdump=llvm-objdump \
  --vdso arch/x86/entry/vdso/vdso64.so.dbg,arch/x86/entry/vdso/vdso32.so.dbg

When doing cross platform analysis, we also need specify the vdso path if
we are interested in its symbols.

Signed-off-by: Changbin Du <changbin.du@xxxxxxxxxx>
---
 tools/perf/builtin-annotate.c |  2 +
 tools/perf/builtin-c2c.c      |  2 +
 tools/perf/builtin-inject.c   |  2 +
 tools/perf/builtin-report.c   |  2 +
 tools/perf/builtin-script.c   |  2 +
 tools/perf/builtin-top.c      |  2 +
 tools/perf/util/symbol.c      | 74 +++++++++++++++++++++++++++++++++++
 tools/perf/util/symbol_conf.h |  5 +++
 8 files changed, 91 insertions(+)

diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
index 50d2fb222d48..ff466882065d 100644
--- a/tools/perf/builtin-annotate.c
+++ b/tools/perf/builtin-annotate.c
@@ -742,6 +742,8 @@ int cmd_annotate(int argc, const char **argv)
 		   "file", "vmlinux pathname"),
 	OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
 		    "load module symbols - WARNING: use only with -k and LIVE kernel"),
+	OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
+		     parse_vdso_pathnames),
 	OPT_BOOLEAN('l', "print-line", &annotate_opts.print_lines,
 		    "print matching source lines (may be slow)"),
 	OPT_BOOLEAN('P', "full-paths", &annotate_opts.full_path,
diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index c157bd31f2e5..4764f9139661 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -3018,6 +3018,8 @@ static int perf_c2c__report(int argc, const char **argv)
 	const struct option options[] = {
 	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
 		   "file", "vmlinux pathname"),
+	OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
+		     parse_vdso_pathnames),
 	OPT_STRING('i', "input", &input_name, "file",
 		   "the input file to process"),
 	OPT_INCR('N', "node-info", &c2c.node_info,
diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index a212678d47be..e774e83d0a0f 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -2247,6 +2247,8 @@ int cmd_inject(int argc, const char **argv)
 			    "don't load vmlinux even if found"),
 		OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name, "file",
 			   "kallsyms pathname"),
+		OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
+		     parse_vdso_pathnames),
 		OPT_BOOLEAN('f', "force", &data.force, "don't complain, do it"),
 		OPT_CALLBACK_OPTARG(0, "itrace", &inject.itrace_synth_opts,
 				    NULL, "opts", "Instruction Tracing options\n"
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 69618fb0110b..a64b48460dce 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -1324,6 +1324,8 @@ int cmd_report(int argc, const char **argv)
                     "don't load vmlinux even if found"),
 	OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name,
 		   "file", "kallsyms pathname"),
+	OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
+		     parse_vdso_pathnames),
 	OPT_BOOLEAN('f', "force", &symbol_conf.force, "don't complain, do it"),
 	OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
 		    "load module symbols - WARNING: use only with -k and LIVE kernel"),
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index c16224b1fef3..2e358922a8d1 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -3965,6 +3965,8 @@ int cmd_script(int argc, const char **argv)
 		   "file", "vmlinux pathname"),
 	OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name,
 		   "file", "kallsyms pathname"),
+	OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
+		     parse_vdso_pathnames),
 	OPT_BOOLEAN('G', "hide-call-graph", &no_callchain,
 		    "When printing symbols do not display call chain"),
 	OPT_CALLBACK(0, "symfs", NULL, "directory",
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 1d6aef51c122..a3cce4e76eb9 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1479,6 +1479,8 @@ int cmd_top(int argc, const char **argv)
 		   "file", "kallsyms pathname"),
 	OPT_BOOLEAN('K', "hide_kernel_symbols", &top.hide_kernel_symbols,
 		    "hide kernel symbols"),
+	OPT_CALLBACK(0, "vdso", NULL, "vdso1[,vdso2]", "vdso pathnames",
+		     parse_vdso_pathnames),
 	OPT_CALLBACK('m', "mmap-pages", &opts->mmap_pages, "pages",
 		     "number of mmap data pages", evlist__parse_mmap_pages),
 	OPT_INTEGER('r', "realtime", &top.realtime_prio,
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 9e5940b5bc59..8d040039a7ce 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -19,6 +19,7 @@
 #include "build-id.h"
 #include "cap.h"
 #include "dso.h"
+#include "vdso.h"
 #include "util.h" // lsdir()
 #include "debug.h"
 #include "event.h"
@@ -44,6 +45,7 @@
 
 static int dso__load_kernel_sym(struct dso *dso, struct map *map);
 static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map);
+static int dso__load_vdso_sym(struct dso *dso, struct map *map);
 static bool symbol__is_idle(const char *name);
 
 int vmlinux_path__nr_entries;
@@ -1833,6 +1835,12 @@ int dso__load(struct dso *dso, struct map *map)
 		goto out;
 	}
 
+	if (dso__is_vdso(dso)) {
+		ret = dso__load_vdso_sym(dso, map);
+		if (ret > 0)
+			goto out;
+	}
+
 	dso__set_adjust_symbols(dso, false);
 
 	if (perfmap) {
@@ -2349,6 +2357,72 @@ static int vmlinux_path__init(struct perf_env *env)
 	return -1;
 }
 
+int parse_vdso_pathnames(const struct option *opt __maybe_unused,
+			 const char *arg, int unset __maybe_unused)
+{
+	char *tmp, *tok, *str = strdup(arg);
+	unsigned int i = 0;
+
+	for (tok = strtok_r(str, ",", &tmp); tok && i < ARRAY_SIZE(symbol_conf.vdso_name);
+	     tok = strtok_r(NULL, ",", &tmp)) {
+		symbol_conf.vdso_name[i++] = strdup(tok);
+	}
+
+	free(str);
+	return 0;
+}
+
+static int dso__load_vdso(struct dso *dso, struct map *map,
+			  const char *vdso)
+{
+	int err = -1;
+	struct symsrc ss;
+	char symfs_vdso[PATH_MAX];
+
+	if (vdso[0] == '/')
+		snprintf(symfs_vdso, sizeof(symfs_vdso), "%s", vdso);
+	else
+		symbol__join_symfs(symfs_vdso, vdso);
+
+	if (symsrc__init(&ss, dso, symfs_vdso, DSO_BINARY_TYPE__SYSTEM_PATH_DSO))
+		return -1;
+
+	/*
+	 * dso__load_sym() may copy 'dso' which will result in the copies having
+	 * an incorrect long name unless we set it here first.
+	 */
+	dso__set_long_name(dso, vdso, false);
+	dso__set_binary_type(dso, DSO_BINARY_TYPE__SYSTEM_PATH_DSO);
+
+	err = dso__load_sym(dso, map, &ss, &ss, 0);
+	symsrc__destroy(&ss);
+
+	if (err > 0) {
+		dso__set_loaded(dso);
+		pr_debug("Using %s for %s symbols\n", symfs_vdso, dso__short_name(dso));
+	}
+
+	return err;
+}
+
+static int dso__load_vdso_sym(struct dso *dso, struct map *map)
+{
+	int ret;
+
+	if (!dso__is_vdso(dso))
+		return -1;
+
+	for (unsigned int i = 0; i < ARRAY_SIZE(symbol_conf.vdso_name); i++) {
+		if (symbol_conf.vdso_name[i] != NULL) {
+			ret = dso__load_vdso(dso, map, symbol_conf.vdso_name[i]);
+			if (ret > 0)
+				return ret;
+		}
+	}
+
+	return -1;
+}
+
 int setup_list(struct strlist **list, const char *list_str,
 		      const char *list_name)
 {
diff --git a/tools/perf/util/symbol_conf.h b/tools/perf/util/symbol_conf.h
index c114bbceef40..108356e3c981 100644
--- a/tools/perf/util/symbol_conf.h
+++ b/tools/perf/util/symbol_conf.h
@@ -3,6 +3,7 @@
 #define __PERF_SYMBOL_CONF 1
 
 #include <stdbool.h>
+#include <subcmd/parse-options.h>
 
 struct strlist;
 struct intlist;
@@ -55,6 +56,7 @@ struct symbol_conf {
 	const char	*default_guest_vmlinux_name,
 			*default_guest_kallsyms,
 			*default_guest_modules;
+	const char	*vdso_name[2];
 	const char	*guestmount;
 	const char	*dso_list_str,
 			*comm_list_str,
@@ -85,4 +87,7 @@ struct symbol_conf {
 
 extern struct symbol_conf symbol_conf;
 
+int parse_vdso_pathnames(const struct option *opt __maybe_unused,
+			 const char *arg, int unset __maybe_unused);
+
 #endif // __PERF_SYMBOL_CONF
-- 
2.34.1