diff options
Diffstat (limited to 'nptl/sysdeps')
| -rw-r--r-- | nptl/sysdeps/x86_64/tls.h | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/nptl/sysdeps/x86_64/tls.h b/nptl/sysdeps/x86_64/tls.h index 4212038ab5..e39eb5f69d 100644 --- a/nptl/sysdeps/x86_64/tls.h +++ b/nptl/sysdeps/x86_64/tls.h @@ -188,7 +188,7 @@ typedef struct The contained asm must *not* be marked volatile since otherwise assignments like - pthread_descr self = thread_self(); + pthread_descr self = thread_self(); do not get optimized away. */ # define THREAD_SELF \ ({ struct pthread *__self; \ @@ -404,7 +404,12 @@ extern void _dl_x86_64_restore_sse (void); # define RTLD_CHECK_FOREIGN_CALL \ (THREAD_GETMEM (THREAD_SELF, header.rtld_must_xmm_save) != 0) +/* NB: Don't use the xchg operation because that would imply a lock + prefix which is expensive and unnecessary. The cache line is also + not contested at all. */ # define RTLD_ENABLE_FOREIGN_CALL \ + int old_rtld_must_xmm_save = THREAD_GETMEM (THREAD_SELF, \ + header.rtld_must_xmm_save); \ THREAD_SETMEM (THREAD_SELF, header.rtld_must_xmm_save, 1) # define RTLD_PREPARE_FOREIGN_CALL \ @@ -419,7 +424,8 @@ extern void _dl_x86_64_restore_sse (void); do { \ if (THREAD_GETMEM (THREAD_SELF, header.rtld_must_xmm_save) == 0) \ _dl_x86_64_restore_sse (); \ - THREAD_SETMEM (THREAD_SELF, header.rtld_must_xmm_save, 0); \ + THREAD_SETMEM (THREAD_SELF, header.rtld_must_xmm_save, \ + old_rtld_must_xmm_save); \ } while (0) # endif |