diff options
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | sysdeps/x86_64/start.S | 17 |
2 files changed, 13 insertions, 9 deletions
@@ -1,5 +1,10 @@ 2016-06-09 H.J. Lu <hongjiu.lu@intel.com> + * sysdeps/x86_64/start.S (_start): Always indirect branch to + __libc_start_main via GOT. + +2016-06-09 H.J. Lu <hongjiu.lu@intel.com> + * sysdeps/x86_64/memcopy.h: New file. * sysdeps/x86_64/wordcopy.c: Likewise. diff --git a/sysdeps/x86_64/start.S b/sysdeps/x86_64/start.S index 2369b69ec3..f1b961f5ba 100644 --- a/sysdeps/x86_64/start.S +++ b/sysdeps/x86_64/start.S @@ -102,23 +102,22 @@ ENTRY (_start) mov __libc_csu_init@GOTPCREL(%rip), %RCX_LP mov main@GOTPCREL(%rip), %RDI_LP - - /* Call the user's main function, and exit with its value. - But let the libc call main. Since __libc_start_main is - called very early, lazy binding isn't relevant here. Use - indirect branch via GOT to avoid extra branch to PLT slot. */ - call *__libc_start_main@GOTPCREL(%rip) #else /* Pass address of our own entry points to .fini and .init. */ mov $__libc_csu_fini, %R8_LP mov $__libc_csu_init, %RCX_LP mov $main, %RDI_LP +#endif /* Call the user's main function, and exit with its value. - But let the libc call main. */ - call __libc_start_main -#endif + But let the libc call main. Since __libc_start_main in + libc.so is called very early, lazy binding isn't relevant + here. Use indirect branch via GOT to avoid extra branch + to PLT slot. In case of static executable, ld in binutils + 2.26 or above can convert indirect branch into direct + branch. */ + call *__libc_start_main@GOTPCREL(%rip) hlt /* Crash if somehow `exit' does return. */ END (_start) |