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Subject[PATCH RFC 05/19] perf tools: Use the _stest symbol to identify the kernel map when loading kcore
Date
The first symbol is not necessarily in the kernel text.  Instead of using
the first symbol, use the _stest symbol to identify the kernel map when
loading kcore.

This allows for the introduction of symbols to identify the x86_64 KPTI
entry trampolines.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
tools/perf/util/symbol.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index f48dc157c2bd..4a39f4d0a174 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1149,7 +1149,7 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
bool is_64_bit;
int err, fd;
char kcore_filename[PATH_MAX];
- struct symbol *sym;
+ u64 stext;

if (!kmaps)
return -EINVAL;
@@ -1198,13 +1198,13 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
old_map = next;
}

- /* Find the kernel map using the first symbol */
- sym = dso__first_symbol(dso);
- list_for_each_entry(new_map, &md.maps, node) {
- if (sym && sym->start >= new_map->start &&
- sym->start < new_map->end) {
- replacement_map = new_map;
- break;
+ /* Find the kernel map using the '_stext' symbol */
+ if (!kallsyms__get_function_start(kallsyms_filename, "_stext", &stext)) {
+ list_for_each_entry(new_map, &md.maps, node) {
+ if (stext >= new_map->start && stext < new_map->end) {
+ replacement_map = new_map;
+ break;
+ }
}
}

--
1.9.1
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