glibc/SOURCES/glibc-rh1991001-11.patch

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2021-12-24 04:19:18 +00:00
commit 2208066603a136f95cfb815ca9281262e6465784
Author: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date: Thu Feb 11 13:24:47 2021 +0000
elf: Remove lazy tlsdesc relocation related code
Remove generic tlsdesc code related to lazy tlsdesc processing since
lazy tlsdesc relocation is no longer supported. This includes removing
GL(dl_load_lock) from _dl_make_tlsdesc_dynamic which is only called at
load time when that lock is already held.
Added a documentation comment too.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
diff --git a/elf/tlsdeschtab.h b/elf/tlsdeschtab.h
index fea9eefe72edcd6b..c20857e5b4264f00 100644
--- a/elf/tlsdeschtab.h
+++ b/elf/tlsdeschtab.h
@@ -78,6 +78,10 @@ map_generation (struct link_map *map)
return GL(dl_tls_generation) + 1;
}
+/* Returns the data pointer for a given map and tls offset that is used
+ to fill in one of the GOT entries referenced by a TLSDESC relocation
+ when using dynamic TLS. This requires allocation, returns NULL on
+ allocation failure. */
void *
_dl_make_tlsdesc_dynamic (struct link_map *map, size_t ti_offset)
{
@@ -85,18 +89,12 @@ _dl_make_tlsdesc_dynamic (struct link_map *map, size_t ti_offset)
void **entry;
struct tlsdesc_dynamic_arg *td, test;
- /* FIXME: We could use a per-map lock here, but is it worth it? */
- __rtld_lock_lock_recursive (GL(dl_load_lock));
-
ht = map->l_mach.tlsdesc_table;
if (! ht)
{
ht = htab_create ();
if (! ht)
- {
- __rtld_lock_unlock_recursive (GL(dl_load_lock));
- return 0;
- }
+ return 0;
map->l_mach.tlsdesc_table = ht;
}
@@ -104,15 +102,11 @@ _dl_make_tlsdesc_dynamic (struct link_map *map, size_t ti_offset)
test.tlsinfo.ti_offset = ti_offset;
entry = htab_find_slot (ht, &test, 1, hash_tlsdesc, eq_tlsdesc);
if (! entry)
- {
- __rtld_lock_unlock_recursive (GL(dl_load_lock));
- return 0;
- }
+ return 0;
if (*entry)
{
td = *entry;
- __rtld_lock_unlock_recursive (GL(dl_load_lock));
return td;
}
@@ -122,44 +116,9 @@ _dl_make_tlsdesc_dynamic (struct link_map *map, size_t ti_offset)
thread. */
td->gen_count = map_generation (map);
td->tlsinfo = test.tlsinfo;
-
- __rtld_lock_unlock_recursive (GL(dl_load_lock));
return td;
}
# endif /* SHARED */
-/* The idea of the following two functions is to stop multiple threads
- from attempting to resolve the same TLS descriptor without busy
- waiting. Ideally, we should be able to release the lock right
- after changing td->entry, and then using say a condition variable
- or a futex wake to wake up any waiting threads, but let's try to
- avoid introducing such dependencies. */
-
-static int
-__attribute__ ((unused))
-_dl_tlsdesc_resolve_early_return_p (struct tlsdesc volatile *td, void *caller)
-{
- if (caller != atomic_load_relaxed (&td->entry))
- return 1;
-
- __rtld_lock_lock_recursive (GL(dl_load_lock));
- if (caller != atomic_load_relaxed (&td->entry))
- {
- __rtld_lock_unlock_recursive (GL(dl_load_lock));
- return 1;
- }
-
- atomic_store_relaxed (&td->entry, _dl_tlsdesc_resolve_hold);
-
- return 0;
-}
-
-static void
-__attribute__ ((unused))
-_dl_tlsdesc_wake_up_held_fixups (void)
-{
- __rtld_lock_unlock_recursive (GL(dl_load_lock));
-}
-
#endif
diff --git a/sysdeps/aarch64/tlsdesc.c b/sysdeps/aarch64/tlsdesc.c
index 357465f23d76e2bd..1ead73ab8250e29c 100644
--- a/sysdeps/aarch64/tlsdesc.c
+++ b/sysdeps/aarch64/tlsdesc.c
@@ -22,7 +22,6 @@
#include <tls.h>
#include <dl-tlsdesc.h>
#include <dl-unmap-segments.h>
-#define _dl_tlsdesc_resolve_hold 0
#include <tlsdeschtab.h>
/* Unmap the dynamic object, but also release its TLS descriptor table
diff --git a/sysdeps/arm/tlsdesc.c b/sysdeps/arm/tlsdesc.c
index d142d7a2c91e9adb..b78e3f65785bf587 100644
--- a/sysdeps/arm/tlsdesc.c
+++ b/sysdeps/arm/tlsdesc.c
@@ -20,7 +20,6 @@
#include <tls.h>
#include <dl-tlsdesc.h>
#include <dl-unmap-segments.h>
-#define _dl_tlsdesc_resolve_hold 0
#include <tlsdeschtab.h>
/* Unmap the dynamic object, but also release its TLS descriptor table
diff --git a/sysdeps/i386/tlsdesc.c b/sysdeps/i386/tlsdesc.c
index 1b4227c8381e1b3d..c242ffce726d50e4 100644
--- a/sysdeps/i386/tlsdesc.c
+++ b/sysdeps/i386/tlsdesc.c
@@ -20,7 +20,6 @@
#include <tls.h>
#include <dl-tlsdesc.h>
#include <dl-unmap-segments.h>
-#define _dl_tlsdesc_resolve_hold 0
#include <tlsdeschtab.h>
/* Unmap the dynamic object, but also release its TLS descriptor table
diff --git a/sysdeps/x86_64/tlsdesc.c b/sysdeps/x86_64/tlsdesc.c
index 61a19ae26944c84f..a9325827d0e5e31b 100644
--- a/sysdeps/x86_64/tlsdesc.c
+++ b/sysdeps/x86_64/tlsdesc.c
@@ -20,7 +20,6 @@
#include <tls.h>
#include <dl-tlsdesc.h>
#include <dl-unmap-segments.h>
-#define _dl_tlsdesc_resolve_hold 0
#include <tlsdeschtab.h>
/* Unmap the dynamic object, but also release its TLS descriptor table