diff options
Diffstat (limited to 'elf')
| -rw-r--r-- | elf/dl-open.c | 6 | ||||
| -rw-r--r-- | elf/dl-reloc.c | 39 |
2 files changed, 44 insertions, 1 deletions
diff --git a/elf/dl-open.c b/elf/dl-open.c index 0e74996473..7dd18b7d97 100644 --- a/elf/dl-open.c +++ b/elf/dl-open.c @@ -34,6 +34,12 @@ #include <dl-dst.h> +#ifdef SHARED +/* Giving this initialized value preallocates some surplus bytes in the + static TLS area, see __libc_setup_tls (libc-tls.c). */ +size_t _dl_tls_static_size = 576; +#endif + extern ElfW(Addr) _dl_sysdep_start (void **start_argptr, void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum, diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c index 16017b3933..37c4be2049 100644 --- a/elf/dl-reloc.c +++ b/elf/dl-reloc.c @@ -35,6 +35,33 @@ #endif +#ifdef USE_TLS +/* We are trying to perform a static TLS relocation in MAP, but it was + dynamically loaded. This can only work if there is enough surplus in + the static TLS area already allocated for each running thread. If this + object's TLS segment is too big to fit, we return false. If it fits, + we set MAP->l_tls_offset and return true. */ +static bool +allocate_static_tls (struct link_map *map) +{ + size_t offset = roundup (GL(dl_tls_static_used), map->l_tls_align); + if (offset + map->l_tls_blocksize > (GL(dl_tls_static_size) +# if TLS_TCB_AT_TP + - TLS_TCB_SIZE +# elif TLS_DTV_AT_TP + /* dl_tls_static_used includes the TCB at the beginning. */ +# else +# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined" +# endif + )) + return false; + map->l_tls_offset = offset; + GL(dl_tls_static_used) = offset + map->l_tls_blocksize; + return true; +} +#endif + + void _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[], int lazy, int consider_profiling) @@ -159,9 +186,19 @@ _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[], l->l_lookup_cache.value = _lr; })) \ : l->l_addr) + /* This macro is used as a callback from elf_machine_rel{a,} when a + static TLS reloc is about to be performed. Since (in dl-load.c) we + permit dynamic loading of objects that might use such relocs, we + have to check whether each use is actually doable. If the object + whose TLS segment the reference resolves to was allocated space in + the static TLS block at startup, then it's ok. Otherwise, we make + an attempt to allocate it in surplus space on the fly. If that + can't be done, we fall back to the error that DF_STATIC_TLS is + intended to produce. */ #define CHECK_STATIC_TLS(map, sym_map) \ do { \ - if (__builtin_expect ((sym_map)->l_tls_offset == 0, 0)) \ + if (__builtin_expect ((sym_map)->l_tls_offset == 0, 0) \ + && !allocate_static_tls (sym_map)) \ { \ errstring = N_("shared object cannot be dlopen()ed"); \ INTUSE(_dl_signal_error) (0, (map)->l_name, NULL, errstring); \ |