[11/23] elf: Move static TLS size and alignment into _rtld_global_ro

Message ID 310d3f42a889e5fd9651cd1be3917f490666630c.1620838411.git.fweimer@redhat.com
State New
Headers show
Series
  • nptl: Move almost all remaining functions into libc
Related show

Commit Message

Andreas K. Huettel via Libc-alpha May 12, 2021, 4:58 p.m.
This helps to clarify that the caching of these fields in libpthread
(in __static_tls_size, __static_tls_align_m1) is unnecessary.
---
 elf/dl-reloc.c             |  6 +++---
 elf/dl-tls.c               | 22 +++++++++++-----------
 elf/rtld_static_init.c     |  6 ++++++
 sysdeps/generic/ldsodefs.h | 10 ++++++----
 4 files changed, 26 insertions(+), 18 deletions(-)

-- 
2.31.1

Comments

Andreas K. Huettel via Libc-alpha May 13, 2021, 7:45 p.m. | #1
On 12/05/2021 13:58, Florian Weimer via Libc-alpha wrote:
> This helps to clarify that the caching of these fields in libpthread

> (in __static_tls_size, __static_tls_align_m1) is unnecessary.


LGTM.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>


> ---

>  elf/dl-reloc.c             |  6 +++---

>  elf/dl-tls.c               | 22 +++++++++++-----------

>  elf/rtld_static_init.c     |  6 ++++++

>  sysdeps/generic/ldsodefs.h | 10 ++++++----

>  4 files changed, 26 insertions(+), 18 deletions(-)

> 

> diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c

> index bb9ca1a101..e13a672ade 100644

> --- a/elf/dl-reloc.c

> +++ b/elf/dl-reloc.c

> @@ -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

>       alignment requirements are too high, fail.  */

>    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:

>        return -1;

>      }

>  

>  #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)

>      goto fail;

>    freebytes -= TLS_TCB_SIZE;

> @@ -89,7 +89,7 @@ _dl_try_allocate_static_tls (struct link_map *map, bool optional)

>  		   + map->l_tls_firstbyte_offset);

>    size_t used = offset + map->l_tls_blocksize;

>  

> -  if (used > GL(dl_tls_static_size))

> +  if (used > GLRO (dl_tls_static_size))

>      goto fail;

>  

>    /* Account optional static TLS surplus usage.  */


Ok.

> diff --git a/elf/dl-tls.c b/elf/dl-tls.c

> index 67781bc108..91031c2b72 100644

> --- a/elf/dl-tls.c

> +++ b/elf/dl-tls.c

> @@ -300,9 +300,9 @@ _dl_determine_tlsoffset (void)

>      }

>  

>    GL(dl_tls_static_used) = offset;

> -  GL(dl_tls_static_size) = (roundup (offset + GLRO(dl_tls_static_surplus),

> -				     max_align)

> -			    + TLS_TCB_SIZE);

> +  GLRO (dl_tls_static_size) = (roundup (offset + GLRO(dl_tls_static_surplus),

> +					max_align)

> +			       + TLS_TCB_SIZE);


Ok.

>  #elif TLS_DTV_AT_TP

>    /* The TLS blocks start right after the TCB.  */

>    size_t offset = TLS_TCB_SIZE;

> @@ -345,14 +345,14 @@ _dl_determine_tlsoffset (void)

>      }

>  

>    GL(dl_tls_static_used) = offset;

> -  GL(dl_tls_static_size) = roundup (offset + GLRO(dl_tls_static_surplus),

> -				    TLS_TCB_ALIGN);

> +  GLRO (dl_tls_static_size) = roundup (offset + GLRO(dl_tls_static_surplus),

> +				       TLS_TCB_ALIGN);

>  #else

>  # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"

>  #endif

>  

>    /* The alignment requirement for the static TLS block.  */

> -  GL(dl_tls_static_align) = max_align;

> +  GLRO (dl_tls_static_align) = max_align;

>  }

>  #endif /* SHARED */

>  

> @@ -391,8 +391,8 @@ allocate_dtv (void *result)

>  void

>  _dl_get_tls_static_info (size_t *sizep, size_t *alignp)

>  {

> -  *sizep = GL(dl_tls_static_size);

> -  *alignp = GL(dl_tls_static_align);

> +  *sizep = GLRO (dl_tls_static_size);

> +  *alignp = GLRO (dl_tls_static_align);

>  }

>  

>  /* Derive the location of the pointer to the start of the original

> @@ -416,7 +416,7 @@ void *

>  _dl_allocate_tls_storage (void)

>  {

>    void *result;

> -  size_t size = GL(dl_tls_static_size);

> +  size_t size = GLRO (dl_tls_static_size);

>  

>  #if TLS_DTV_AT_TP

>    /* Memory layout is:

> @@ -427,7 +427,7 @@ _dl_allocate_tls_storage (void)

>  

>    /* Perform the allocation.  Reserve space for the required alignment

>       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 *));

>    if (__glibc_unlikely (allocated == NULL))

>      return NULL;

> @@ -436,7 +436,7 @@ _dl_allocate_tls_storage (void)

>  #if TLS_TCB_AT_TP

>    /* The TCB follows the TLS blocks, which determine the alignment.

>       (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);

>    result = aligned + size - TLS_TCB_SIZE;

>  


Ok.

> diff --git a/elf/rtld_static_init.c b/elf/rtld_static_init.c

> index cd823096d6..bded6bd2d4 100644

> --- a/elf/rtld_static_init.c

> +++ b/elf/rtld_static_init.c

> @@ -51,6 +51,12 @@ __rtld_static_init (struct link_map *map)

>    dl->_dl_hwcap2 = _dl_hwcap2;

>    extern __typeof (dl->_dl_pagesize) _dl_pagesize attribute_hidden;

>    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);

>  }


Ok.

> diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h

> index c288f3a2a1..e383aa1dc3 100644

> --- a/sysdeps/generic/ldsodefs.h

> +++ b/sysdeps/generic/ldsodefs.h

> @@ -437,12 +437,8 @@ struct rtld_global

>    } *_dl_tls_dtv_slotinfo_list;

>    /* Number of modules in the static TLS block.  */

>    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.  */

>    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

>       dynamic TLS access (e.g. with TLSDESC).  */

>    EXTERN size_t _dl_tls_static_optional;

> @@ -610,6 +606,12 @@ struct rtld_global_ro

>       binaries, don't honor for PIEs).  */

>    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

>       loaded modules with IE-model TLS or for TLSDESC optimization.

>       See comments in elf/dl-tls.c where it is initialized.  */

> 


Ok.

Patch

diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c
index bb9ca1a101..e13a672ade 100644
--- a/elf/dl-reloc.c
+++ b/elf/dl-reloc.c
@@ -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
      alignment requirements are too high, fail.  */
   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:
       return -1;
     }
 
 #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)
     goto fail;
   freebytes -= TLS_TCB_SIZE;
@@ -89,7 +89,7 @@  _dl_try_allocate_static_tls (struct link_map *map, bool optional)
 		   + map->l_tls_firstbyte_offset);
   size_t used = offset + map->l_tls_blocksize;
 
-  if (used > GL(dl_tls_static_size))
+  if (used > GLRO (dl_tls_static_size))
     goto fail;
 
   /* Account optional static TLS surplus usage.  */
diff --git a/elf/dl-tls.c b/elf/dl-tls.c
index 67781bc108..91031c2b72 100644
--- a/elf/dl-tls.c
+++ b/elf/dl-tls.c
@@ -300,9 +300,9 @@  _dl_determine_tlsoffset (void)
     }
 
   GL(dl_tls_static_used) = offset;
-  GL(dl_tls_static_size) = (roundup (offset + GLRO(dl_tls_static_surplus),
-				     max_align)
-			    + TLS_TCB_SIZE);
+  GLRO (dl_tls_static_size) = (roundup (offset + GLRO(dl_tls_static_surplus),
+					max_align)
+			       + TLS_TCB_SIZE);
 #elif TLS_DTV_AT_TP
   /* The TLS blocks start right after the TCB.  */
   size_t offset = TLS_TCB_SIZE;
@@ -345,14 +345,14 @@  _dl_determine_tlsoffset (void)
     }
 
   GL(dl_tls_static_used) = offset;
-  GL(dl_tls_static_size) = roundup (offset + GLRO(dl_tls_static_surplus),
-				    TLS_TCB_ALIGN);
+  GLRO (dl_tls_static_size) = roundup (offset + GLRO(dl_tls_static_surplus),
+				       TLS_TCB_ALIGN);
 #else
 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
 #endif
 
   /* The alignment requirement for the static TLS block.  */
-  GL(dl_tls_static_align) = max_align;
+  GLRO (dl_tls_static_align) = max_align;
 }
 #endif /* SHARED */
 
@@ -391,8 +391,8 @@  allocate_dtv (void *result)
 void
 _dl_get_tls_static_info (size_t *sizep, size_t *alignp)
 {
-  *sizep = GL(dl_tls_static_size);
-  *alignp = GL(dl_tls_static_align);
+  *sizep = GLRO (dl_tls_static_size);
+  *alignp = GLRO (dl_tls_static_align);
 }
 
 /* Derive the location of the pointer to the start of the original
@@ -416,7 +416,7 @@  void *
 _dl_allocate_tls_storage (void)
 {
   void *result;
-  size_t size = GL(dl_tls_static_size);
+  size_t size = GLRO (dl_tls_static_size);
 
 #if TLS_DTV_AT_TP
   /* Memory layout is:
@@ -427,7 +427,7 @@  _dl_allocate_tls_storage (void)
 
   /* Perform the allocation.  Reserve space for the required alignment
      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 *));
   if (__glibc_unlikely (allocated == NULL))
     return NULL;
@@ -436,7 +436,7 @@  _dl_allocate_tls_storage (void)
 #if TLS_TCB_AT_TP
   /* The TCB follows the TLS blocks, which determine the alignment.
      (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);
   result = aligned + size - TLS_TCB_SIZE;
 
diff --git a/elf/rtld_static_init.c b/elf/rtld_static_init.c
index cd823096d6..bded6bd2d4 100644
--- a/elf/rtld_static_init.c
+++ b/elf/rtld_static_init.c
@@ -51,6 +51,12 @@  __rtld_static_init (struct link_map *map)
   dl->_dl_hwcap2 = _dl_hwcap2;
   extern __typeof (dl->_dl_pagesize) _dl_pagesize attribute_hidden;
   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);
 }
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index c288f3a2a1..e383aa1dc3 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -437,12 +437,8 @@  struct rtld_global
   } *_dl_tls_dtv_slotinfo_list;
   /* Number of modules in the static TLS block.  */
   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.  */
   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
      dynamic TLS access (e.g. with TLSDESC).  */
   EXTERN size_t _dl_tls_static_optional;
@@ -610,6 +606,12 @@  struct rtld_global_ro
      binaries, don't honor for PIEs).  */
   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
      loaded modules with IE-model TLS or for TLSDESC optimization.
      See comments in elf/dl-tls.c where it is initialized.  */