diff options
Diffstat (limited to 'sysdeps/aarch64/tlsdesc.c')
| -rw-r--r-- | sysdeps/aarch64/tlsdesc.c | 36 |
1 files changed, 24 insertions, 12 deletions
diff --git a/sysdeps/aarch64/tlsdesc.c b/sysdeps/aarch64/tlsdesc.c index 4821f8c08a..9f3ff9b662 100644 --- a/sysdeps/aarch64/tlsdesc.c +++ b/sysdeps/aarch64/tlsdesc.c @@ -25,6 +25,7 @@ #include <dl-tlsdesc.h> #include <dl-unmap-segments.h> #include <tlsdeschtab.h> +#include <atomic.h> /* The following functions take an entry_check_offset argument. It's computed by the caller as an offset between its entry point and the @@ -39,11 +40,15 @@ void attribute_hidden -_dl_tlsdesc_resolve_rela_fixup (struct tlsdesc volatile *td, - struct link_map *l) +_dl_tlsdesc_resolve_rela_fixup (struct tlsdesc *td, struct link_map *l) { - const ElfW(Rela) *reloc = td->arg; + const ElfW(Rela) *reloc = atomic_load_relaxed (&td->arg); + /* After GL(dl_load_lock) is grabbed only one caller can see td->entry in + initial state in _dl_tlsdesc_resolve_early_return_p, other concurrent + callers will return and retry calling td->entry. The updated td->entry + synchronizes with the single writer so all read accesses here can use + relaxed order. */ if (_dl_tlsdesc_resolve_early_return_p (td, (void*)(D_PTR (l, l_info[ADDRIDX (DT_TLSDESC_PLT)]) + l->l_addr))) return; @@ -86,8 +91,10 @@ _dl_tlsdesc_resolve_rela_fixup (struct tlsdesc volatile *td, if (!sym) { - td->arg = (void*) reloc->r_addend; - td->entry = _dl_tlsdesc_undefweak; + atomic_store_relaxed (&td->arg, (void *) reloc->r_addend); + /* This release store synchronizes with the ldar acquire load + instruction in _dl_tlsdesc_undefweak. */ + atomic_store_release (&td->entry, _dl_tlsdesc_undefweak); } else { @@ -96,16 +103,22 @@ _dl_tlsdesc_resolve_rela_fixup (struct tlsdesc volatile *td, # else if (!TRY_STATIC_TLS (l, result)) { - td->arg = _dl_make_tlsdesc_dynamic (result, sym->st_value + void *p = _dl_make_tlsdesc_dynamic (result, sym->st_value + reloc->r_addend); - td->entry = _dl_tlsdesc_dynamic; + atomic_store_relaxed (&td->arg, p); + /* This release store synchronizes with the ldar acquire load + instruction in _dl_tlsdesc_dynamic. */ + atomic_store_release (&td->entry, _dl_tlsdesc_dynamic); } else # endif { - td->arg = (void*) (sym->st_value + result->l_tls_offset + void *p = (void*) (sym->st_value + result->l_tls_offset + reloc->r_addend); - td->entry = _dl_tlsdesc_return; + atomic_store_relaxed (&td->arg, p); + /* This release store synchronizes with the ldar acquire load + instruction in _dl_tlsdesc_return_lazy. */ + atomic_store_release (&td->entry, _dl_tlsdesc_return_lazy); } } @@ -120,11 +133,10 @@ _dl_tlsdesc_resolve_rela_fixup (struct tlsdesc volatile *td, void attribute_hidden -_dl_tlsdesc_resolve_hold_fixup (struct tlsdesc volatile *td, - void *caller) +_dl_tlsdesc_resolve_hold_fixup (struct tlsdesc *td, void *caller) { /* Maybe we're lucky and can return early. */ - if (caller != td->entry) + if (caller != atomic_load_relaxed (&td->entry)) return; /* Locking here will stop execution until the running resolver runs |