[PATCH v6 1/8] perf: support specify vdso path in cmdline
From: Changbin Du
Date: Wed Jul 24 2024 - 22:16:38 EST
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
Samples: 17K of event 'cycles:P', 4000 Hz, Event count (approx.): 1760
__vdso_clock_gettime /work/linux-host/arch/x86/entry/vdso/vdso64.so.d
Percent│ movq -48(%rbp),%rsi
│ testq %rax,%rax
│ ; return vread_hvclock();
│ movq %rax,%rdx
│ ; if (unlikely(!vdso_cycles_ok(cycles)))
│ ↑ js eb
│ ↑ jmp 74
│ ; ts->tv_sec = vdso_ts->sec;
0.02 │147: leaq 2(%rbx),%rax
│ shlq $4, %rax
│ addq %r10,%rax
│ ; while ((seq = READ_ONCE(vd->seq)) & 1) {
9.38 │152: movl (%r10),%ecx
When doing cross platform analysis, we also need specify the vdso path if
we are interested in its symbols.
v2: update documentation.
Signed-off-by: Changbin Du <changbin.du@xxxxxxxxxx>
---
tools/perf/Documentation/perf-annotate.txt | 3 +
tools/perf/Documentation/perf-c2c.txt | 3 +
tools/perf/Documentation/perf-inject.txt | 3 +
tools/perf/Documentation/perf-report.txt | 3 +
tools/perf/Documentation/perf-script.txt | 3 +
tools/perf/Documentation/perf-top.txt | 3 +
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/disasm.c | 7 +-
tools/perf/util/symbol.c | 82 +++++++++++++++++++++-
tools/perf/util/symbol_conf.h | 5 ++
15 files changed, 119 insertions(+), 5 deletions(-)
diff --git a/tools/perf/Documentation/perf-annotate.txt b/tools/perf/Documentation/perf-annotate.txt
index b95524bea021..4b6692f9a793 100644
--- a/tools/perf/Documentation/perf-annotate.txt
+++ b/tools/perf/Documentation/perf-annotate.txt
@@ -58,6 +58,9 @@ OPTIONS
--ignore-vmlinux::
Ignore vmlinux files.
+--vdso=<vdso1[,vdso2]>::
+ Specify vdso pathnames. You can specify up to two for multiarch-support.
+
--itrace::
Options for decoding instruction tracing data. The options are:
diff --git a/tools/perf/Documentation/perf-c2c.txt b/tools/perf/Documentation/perf-c2c.txt
index 856f0dfb8e5a..7c07efca7542 100644
--- a/tools/perf/Documentation/perf-c2c.txt
+++ b/tools/perf/Documentation/perf-c2c.txt
@@ -71,6 +71,9 @@ REPORT OPTIONS
--vmlinux=<file>::
vmlinux pathname
+--vdso=<vdso1[,vdso2]>::
+ Specify vdso pathnames. You can specify up to two for multiarch-support.
+
-v::
--verbose::
Be more verbose (show counter open errors, etc).
diff --git a/tools/perf/Documentation/perf-inject.txt b/tools/perf/Documentation/perf-inject.txt
index c972032f4ca0..3c88967b4c7f 100644
--- a/tools/perf/Documentation/perf-inject.txt
+++ b/tools/perf/Documentation/perf-inject.txt
@@ -62,6 +62,9 @@ OPTIONS
--kallsyms=<file>::
kallsyms pathname
+--vdso=<vdso1[,vdso2]>::
+ Specify vdso pathnames. You can specify up to two for multiarch-support.
+
--itrace::
Decode Instruction Tracing data, replacing it with synthesized events.
Options are:
diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index d2b1593ef700..8a3ba5f74cac 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -345,6 +345,9 @@ OPTIONS
Load module symbols. WARNING: This should only be used with -k and
a LIVE kernel.
+--vdso=<vdso1[,vdso2]>::
+ Specify vdso pathnames. You can specify up to two for multiarch-support.
+
-f::
--force::
Don't do ownership validation.
diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
index ff086ef05a0c..48f9974ca4c5 100644
--- a/tools/perf/Documentation/perf-script.txt
+++ b/tools/perf/Documentation/perf-script.txt
@@ -296,6 +296,9 @@ OPTIONS
--kallsyms=<file>::
kallsyms pathname
+--vdso=<vdso1[,vdso2]>::
+ Specify vdso pathnames. You can specify up to two for multiarch-support.
+
--symfs=<directory>::
Look for files with symbols relative to this directory.
diff --git a/tools/perf/Documentation/perf-top.txt b/tools/perf/Documentation/perf-top.txt
index 667e5102075e..99f53b5b336b 100644
--- a/tools/perf/Documentation/perf-top.txt
+++ b/tools/perf/Documentation/perf-top.txt
@@ -80,6 +80,9 @@ Default is to monitor all CPUS.
--kallsyms=<file>::
kallsyms pathname
+--vdso=<vdso1[,vdso2]>::
+ Specify vdso pathnames. You can specify up to two for multiarch-support.
+
-m <pages>::
--mmap-pages=<pages>::
Number of mmap data pages (must be a power of two) or size
diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
index b10b7f005658..e0aa657e6ca0 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 6edc0d4ce6fb..00ddf4f06324 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -1321,6 +1321,8 @@ 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 e8cbbf10d361..3a4cee6f2d2f 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1488,6 +1488,8 @@ 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/disasm.c b/tools/perf/util/disasm.c
index e10558b79504..7e26d5215640 100644
--- a/tools/perf/util/disasm.c
+++ b/tools/perf/util/disasm.c
@@ -16,6 +16,7 @@
#include "debug.h"
#include "disasm.h"
#include "dso.h"
+#include "vdso.h"
#include "env.h"
#include "evsel.h"
#include "map.h"
@@ -1126,7 +1127,7 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
if (pos && strlen(pos) < SBUILD_ID_SIZE - 2)
dirname(build_id_path);
- if (dso__is_kcore(dso))
+ if (dso__is_kcore(dso) || dso__is_vdso(dso))
goto fallback;
len = readlink(build_id_path, linkname, sizeof(linkname) - 1);
@@ -1134,7 +1135,7 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
goto fallback;
linkname[len] = '\0';
- if (strstr(linkname, DSO__NAME_KALLSYMS) ||
+ if (strstr(linkname, DSO__NAME_KALLSYMS) || strstr(linkname, DSO__NAME_VDSO) ||
access(filename, R_OK)) {
fallback:
/*
@@ -1142,7 +1143,7 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
* cache, or is just a kallsyms file, well, lets hope that this
* DSO is the same as when 'perf record' ran.
*/
- if (dso__kernel(dso) && dso__long_name(dso)[0] == '/')
+ if ((dso__kernel(dso) || dso__is_vdso(dso)) && dso__long_name(dso)[0] == '/')
snprintf(filename, filename_size, "%s", dso__long_name(dso));
else
__symbol__join_symfs(filename, filename_size, dso__long_name(dso));
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 19eb623e0826..ad3b7b929e94 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;
@@ -1832,6 +1834,12 @@ 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) {
@@ -2016,12 +2024,14 @@ int dso__load_vmlinux(struct dso *dso, struct map *map,
dso__set_binary_type(dso, DSO_BINARY_TYPE__VMLINUX);
err = dso__load_sym(dso, map, &ss, &ss, 0);
- symsrc__destroy(&ss);
-
if (err > 0) {
dso__set_loaded(dso);
pr_debug("Using %s for symbols\n", symfs_vmlinux);
+
+ if (symsrc__has_symtab(&ss) && !dso__symsrc_filename(dso))
+ dso__set_symsrc_filename(dso, strdup(symfs_vmlinux));
}
+ symsrc__destroy(&ss);
return err;
}
@@ -2348,6 +2358,74 @@ 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);
+ if (err > 0) {
+ dso__set_loaded(dso);
+ pr_debug("Using %s for %s symbols\n", symfs_vdso, dso__short_name(dso));
+
+ if (symsrc__has_symtab(&ss) && !dso__symsrc_filename(dso))
+ dso__set_symsrc_filename(dso, strdup(symfs_vdso));
+ }
+ symsrc__destroy(&ss);
+
+ 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 657cfa5af43c..deaec9a60904 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;
@@ -56,6 +57,7 @@ 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,
@@ -86,4 +88,7 @@ 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