From 600d9e0c87940da9b0fdeff492bf888df852d40c Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Fri, 4 Dec 2020 09:13:43 +0100 Subject: elf: Add glibc-hwcaps subdirectory support to ld.so cache processing This recognizes the DL_CACHE_HWCAP_EXTENSION flag in cache entries, and picks the supported cache entry with the highest priority. The elf/tst-glibc-hwcaps-prepend-cache test documents a non-desired aspect of the current cache implementation: If the cache selects a DSO that does not exist on disk, _dl_map_object falls back to open_path, which may or may not find an alternative implementation. This is an existing limitation that also applies to the legacy hwcaps processing for ld.so.cache. Reviewed-by: Adhemerval Zanella --- elf/dl-hwcaps.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'elf/dl-hwcaps.h') diff --git a/elf/dl-hwcaps.h b/elf/dl-hwcaps.h index ab39d8a46d..e6fcac6edc 100644 --- a/elf/dl-hwcaps.h +++ b/elf/dl-hwcaps.h @@ -132,4 +132,23 @@ _dl_hwcaps_subdirs_build_bitmask (int subdirs, int active) return mask ^ ((1U << inactive) - 1); } +/* Pre-computed glibc-hwcaps subdirectory priorities. Used in + dl-cache.c to quickly find the proprieties for the stored HWCAP + names. */ +struct dl_hwcaps_priority +{ + /* The name consists of name_length bytes at name (not necessarily + null-terminated). */ + const char *name; + uint32_t name_length; + + /* Priority of this name. A positive number. */ + uint32_t priority; +}; + +/* Pre-computed hwcaps priorities. Set up by + _dl_important_hwcaps. */ +extern struct dl_hwcaps_priority *_dl_hwcaps_priorities attribute_hidden; +extern uint32_t _dl_hwcaps_priorities_length attribute_hidden; + #endif /* _DL_HWCAPS_H */ -- cgit 1.4.1