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authorRoland McGrath <roland@gnu.org>2002-11-05 03:01:37 +0000
committerRoland McGrath <roland@gnu.org>2002-11-05 03:01:37 +0000
commitc56baa872be4a23813de943f90b1808767eb9430 (patch)
tree737acf138fbfbf32779bd9a9e02c9c8e7d6a6da7 /elf/dl-reloc.c
parent2f0f157e1c222a91a74d3a14292c28538972fa63 (diff)
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2002-11-03 Roland McGrath <roland@redhat.com>
* sysdeps/generic/ldsodefs.h (struct rtld_global): New member `_dl_tls_static_used'. * sysdeps/generic/libc-tls.c (_dl_tls_static_used): New variable. (__libc_setup_tls): Initialize it. Let the initial value of _dl_tls_static_size indicate some surplus space in the computed value. * elf/dl-open.c (_dl_tls_static_size): New variable. * sysdeps/generic/dl-tls.c (_dl_determine_tlsoffset): Initialize _dl_tls_static_used. Add some surplus space into _dl_tls_static_size. * elf/dl-reloc.c [USE_TLS] (allocate_static_tls): New function. (CHECK_STATIC_TLS): Use it. * elf/dl-close.c (_dl_close): Adjust _dl_tls_static_used when the closed objects occupied a trailing contiguous chunk of static TLS area.
Diffstat (limited to 'elf/dl-reloc.c')
-rw-r--r--elf/dl-reloc.c39
1 files changed, 38 insertions, 1 deletions
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); \