[PATCH V2 3/5] Force MAPPING_TYPE__IDENTIY for PIE
Leo Yan
leo.yan at arm.com
Tue Aug 27 12:55:52 PDT 2024
On 8/26/2024 10:35 PM, Steve Clevenger wrote:
>
> Changes in V2:
> - Updated mailing list distribution
>
> Use dso__is_pie() to check whether the DSO file is a Position
> Independent Executable (PIE). If PIE, change the MAPPING_TYPE to
> MAPPING_TYPE__IDENTITY so a zero map pgoff (text offset) is passed
> into the script.
>
>
> Signed-off-by: Steve Clevenger <scclevenger at os.amperecomputing.com>
> ---
> tools/perf/util/map.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> index e1d14936a60d..df7c06fc373e 100644
> --- a/tools/perf/util/map.c
> +++ b/tools/perf/util/map.c
> @@ -171,8 +171,11 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
> assert(!dso__kernel(dso));
> map__init(result, start, start + len, pgoff, dso);
>
> + if (map->pgoff && !no_dso)
> + no_dso = dso__is_pie(dso); // PIE check
Here the logic is whatever the `pgoff` is (zero or non-zero), we need to
always set the mapping type as MAPPING_TYPE__IDENTITY. It is no need to check
pgoff and is no matter with 'no_dso'. So we can simply check dso__is_pie() and
set IDENTITY flag for the true case.
if (dso__is_pie(dso)) {
map__set_mapping_type(map, MAPPING_TYPE__IDENTITY);
} else if (anon || no_dso) {
...
}
BTW, please rebase the series on the top of the perf-tools-next branch [1], I
saw this patch has merging conflict on it.
Thanks,
Leo
[1] https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git
branch: perf-tools-next
> +
> if (anon || no_dso) {
> - map->mapping_type = MAPPING_TYPE__IDENTITY;
> + map__set_mapping_type(map, MAPPING_TYPE__IDENTITY);
>
> /*
> * Set memory without DSO as loaded. All map__find_*
> --
> 2.25.1
>
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