elf: Move static TLS size and alignment into _rtld_global_ro

This helps to clarify that the caching of these fields in libpthread
(in __static_tls_size, __static_tls_align_m1) is unnecessary.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Florian Weimer 2021-05-17 09:59:14 +02:00
parent 0b3e92bdf3
commit 9dc21009a4
4 changed files with 26 additions and 18 deletions

View File

@ -53,14 +53,14 @@ _dl_try_allocate_static_tls (struct link_map *map, bool optional)
/* If we've already used the variable with dynamic access, or if the /* If we've already used the variable with dynamic access, or if the
alignment requirements are too high, fail. */ alignment requirements are too high, fail. */
if (map->l_tls_offset == FORCED_DYNAMIC_TLS_OFFSET if (map->l_tls_offset == FORCED_DYNAMIC_TLS_OFFSET
|| map->l_tls_align > GL(dl_tls_static_align)) || map->l_tls_align > GLRO (dl_tls_static_align))
{ {
fail: fail:
return -1; return -1;
} }
#if TLS_TCB_AT_TP #if TLS_TCB_AT_TP
size_t freebytes = GL(dl_tls_static_size) - GL(dl_tls_static_used); size_t freebytes = GLRO (dl_tls_static_size) - GL(dl_tls_static_used);
if (freebytes < TLS_TCB_SIZE) if (freebytes < TLS_TCB_SIZE)
goto fail; goto fail;
freebytes -= TLS_TCB_SIZE; freebytes -= TLS_TCB_SIZE;
@ -89,7 +89,7 @@ _dl_try_allocate_static_tls (struct link_map *map, bool optional)
+ map->l_tls_firstbyte_offset); + map->l_tls_firstbyte_offset);
size_t used = offset + map->l_tls_blocksize; size_t used = offset + map->l_tls_blocksize;
if (used > GL(dl_tls_static_size)) if (used > GLRO (dl_tls_static_size))
goto fail; goto fail;
/* Account optional static TLS surplus usage. */ /* Account optional static TLS surplus usage. */

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@ -300,9 +300,9 @@ _dl_determine_tlsoffset (void)
} }
GL(dl_tls_static_used) = offset; GL(dl_tls_static_used) = offset;
GL(dl_tls_static_size) = (roundup (offset + GLRO(dl_tls_static_surplus), GLRO (dl_tls_static_size) = (roundup (offset + GLRO(dl_tls_static_surplus),
max_align) max_align)
+ TLS_TCB_SIZE); + TLS_TCB_SIZE);
#elif TLS_DTV_AT_TP #elif TLS_DTV_AT_TP
/* The TLS blocks start right after the TCB. */ /* The TLS blocks start right after the TCB. */
size_t offset = TLS_TCB_SIZE; size_t offset = TLS_TCB_SIZE;
@ -345,14 +345,14 @@ _dl_determine_tlsoffset (void)
} }
GL(dl_tls_static_used) = offset; GL(dl_tls_static_used) = offset;
GL(dl_tls_static_size) = roundup (offset + GLRO(dl_tls_static_surplus), GLRO (dl_tls_static_size) = roundup (offset + GLRO(dl_tls_static_surplus),
TLS_TCB_ALIGN); TLS_TCB_ALIGN);
#else #else
# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined" # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
#endif #endif
/* The alignment requirement for the static TLS block. */ /* The alignment requirement for the static TLS block. */
GL(dl_tls_static_align) = max_align; GLRO (dl_tls_static_align) = max_align;
} }
#endif /* SHARED */ #endif /* SHARED */
@ -391,8 +391,8 @@ allocate_dtv (void *result)
void void
_dl_get_tls_static_info (size_t *sizep, size_t *alignp) _dl_get_tls_static_info (size_t *sizep, size_t *alignp)
{ {
*sizep = GL(dl_tls_static_size); *sizep = GLRO (dl_tls_static_size);
*alignp = GL(dl_tls_static_align); *alignp = GLRO (dl_tls_static_align);
} }
/* Derive the location of the pointer to the start of the original /* Derive the location of the pointer to the start of the original
@ -416,7 +416,7 @@ void *
_dl_allocate_tls_storage (void) _dl_allocate_tls_storage (void)
{ {
void *result; void *result;
size_t size = GL(dl_tls_static_size); size_t size = GLRO (dl_tls_static_size);
#if TLS_DTV_AT_TP #if TLS_DTV_AT_TP
/* Memory layout is: /* Memory layout is:
@ -427,7 +427,7 @@ _dl_allocate_tls_storage (void)
/* Perform the allocation. Reserve space for the required alignment /* Perform the allocation. Reserve space for the required alignment
and the pointer to the original allocation. */ and the pointer to the original allocation. */
size_t alignment = GL(dl_tls_static_align); size_t alignment = GLRO (dl_tls_static_align);
void *allocated = malloc (size + alignment + sizeof (void *)); void *allocated = malloc (size + alignment + sizeof (void *));
if (__glibc_unlikely (allocated == NULL)) if (__glibc_unlikely (allocated == NULL))
return NULL; return NULL;
@ -436,7 +436,7 @@ _dl_allocate_tls_storage (void)
#if TLS_TCB_AT_TP #if TLS_TCB_AT_TP
/* The TCB follows the TLS blocks, which determine the alignment. /* The TCB follows the TLS blocks, which determine the alignment.
(TCB alignment requirements have been taken into account when (TCB alignment requirements have been taken into account when
calculating GL(dl_tls_static_align).) */ calculating GLRO (dl_tls_static_align).) */
void *aligned = (void *) roundup ((uintptr_t) allocated, alignment); void *aligned = (void *) roundup ((uintptr_t) allocated, alignment);
result = aligned + size - TLS_TCB_SIZE; result = aligned + size - TLS_TCB_SIZE;

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@ -51,6 +51,12 @@ __rtld_static_init (struct link_map *map)
dl->_dl_hwcap2 = _dl_hwcap2; dl->_dl_hwcap2 = _dl_hwcap2;
extern __typeof (dl->_dl_pagesize) _dl_pagesize attribute_hidden; extern __typeof (dl->_dl_pagesize) _dl_pagesize attribute_hidden;
dl->_dl_pagesize = _dl_pagesize; dl->_dl_pagesize = _dl_pagesize;
extern __typeof (dl->_dl_tls_static_align) _dl_tls_static_align
attribute_hidden;
dl->_dl_tls_static_align = _dl_tls_static_align;
extern __typeof (dl->_dl_tls_static_size) _dl_tls_static_size
attribute_hidden;
dl->_dl_tls_static_size = _dl_tls_static_size;
__rtld_static_init_arch (map, dl); __rtld_static_init_arch (map, dl);
} }

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@ -437,12 +437,8 @@ struct rtld_global
} *_dl_tls_dtv_slotinfo_list; } *_dl_tls_dtv_slotinfo_list;
/* Number of modules in the static TLS block. */ /* Number of modules in the static TLS block. */
EXTERN size_t _dl_tls_static_nelem; EXTERN size_t _dl_tls_static_nelem;
/* Size of the static TLS block. */
EXTERN size_t _dl_tls_static_size;
/* Size actually allocated in the static TLS block. */ /* Size actually allocated in the static TLS block. */
EXTERN size_t _dl_tls_static_used; EXTERN size_t _dl_tls_static_used;
/* Alignment requirement of the static TLS block. */
EXTERN size_t _dl_tls_static_align;
/* Remaining amount of static TLS that may be used for optimizing /* Remaining amount of static TLS that may be used for optimizing
dynamic TLS access (e.g. with TLSDESC). */ dynamic TLS access (e.g. with TLSDESC). */
EXTERN size_t _dl_tls_static_optional; EXTERN size_t _dl_tls_static_optional;
@ -610,6 +606,12 @@ struct rtld_global_ro
binaries, don't honor for PIEs). */ binaries, don't honor for PIEs). */
EXTERN ElfW(Addr) _dl_use_load_bias; EXTERN ElfW(Addr) _dl_use_load_bias;
/* Size of the static TLS block. */
EXTERN size_t _dl_tls_static_size;
/* Alignment requirement of the static TLS block. */
EXTERN size_t _dl_tls_static_align;
/* Size of surplus space in the static TLS area for dynamically /* Size of surplus space in the static TLS area for dynamically
loaded modules with IE-model TLS or for TLSDESC optimization. loaded modules with IE-model TLS or for TLSDESC optimization.
See comments in elf/dl-tls.c where it is initialized. */ See comments in elf/dl-tls.c where it is initialized. */