[tip:perf/urgent] perf machine: Read also the end of the kernel

tip-bot for Jiri Olsa
2019-05-28T21:30:01Z

Commit-ID: ed9adb2035b5be5896d465b19040262be5f4a824
Gitweb: https://git.kernel.org/tip/ed9adb2035b5be5896d465b19040262be5f4a824
Author: Jiri Olsa <jolsa@kernel.org>
AuthorDate: Wed, 8 May 2019 15:20:03 +0200
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 28 May 2019 09:52:23 -0300

perf machine: Read also the end of the kernel

We mark the end of kernel based on the first module, but that could
cover some bpf program maps. Reading _etext symbol if it's present to
get precise kernel map end.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: http://lkml.kernel.org/r/20190508132010.14512-6-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/machine.c | 27 ++++++++++++++++++---------
1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 28a9541c4835..dc7aafe45a2b 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -924,7 +924,8 @@ const char *ref_reloc_sym_names[] = {"_text", "_stext", NULL};
* symbol_name if it's not that important.
*/
static int machine__get_running_kernel_start(struct machine *machine,
- const char **symbol_name, u64 *start)
+ const char **symbol_name,
+ u64 *start, u64 *end)
{
char filename[PATH_MAX];
int i, err = -1;
@@ -949,6 +950,11 @@ static int machine__get_running_kernel_start(struct machine *machine,
*symbol_name = name;

*start = addr;
+
+ err = kallsyms__get_function_start(filename, "_etext", &addr);
+ if (!err)
+ *end = addr;
+
return 0;
}

@@ -1441,7 +1447,7 @@ int machine__create_kernel_maps(struct machine *machine)
struct dso *kernel = machine__get_kernel(machine);
const char *name = NULL;
struct map *map;
- u64 addr = 0;
+ u64 start = 0, end = ~0ULL;
int ret;

if (kernel == NULL)
@@ -1460,9 +1466,9 @@ int machine__create_kernel_maps(struct machine *machine)
"continuing anyway...\n", machine->pid);
}

- if (!machine__get_running_kernel_start(machine, &name, &addr)) {
+ if (!machine__get_running_kernel_start(machine, &name, &start, &end)) {
if (name &&
- map__set_kallsyms_ref_reloc_sym(machine->vmlinux_map, name, addr)) {
+ map__set_kallsyms_ref_reloc_sym(machine->vmlinux_map, name, start)) {
machine__destroy_kernel_maps(machine);
ret = -1;
goto out_put;
@@ -1472,16 +1478,19 @@ int machine__create_kernel_maps(struct machine *machine)
* we have a real start address now, so re-order the kmaps
* assume it's the last in the kmaps
*/
- machine__update_kernel_mmap(machine, addr, ~0ULL);
+ machine__update_kernel_mmap(machine, start, end);
}

if (machine__create_extra_kernel_maps(machine, kernel))
pr_debug("Problems creating extra kernel maps, continuing anyway...\n");

- /* update end address of the kernel map using adjacent module address */
- map = map__next(machine__kernel_map(machine));
- if (map)
- machine__set_kernel_mmap(machine, addr, map->start);
+ if (end == ~0ULL) {
+ /* update end address of the kernel map using adjacent module address */
+ map = map__next(machine__kernel_map(machine));
+ if (map)
+ machine__set_kernel_mmap(machine, start, map->start);
+ }
+
out_put:
dso__put(kernel);
return ret;