From 4088d8dd29ce0629eeaa7cceca02414c85d98e05 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 28 Sep 2017 15:28:00 -0700 Subject: x86: Allow undefined _DYNAMIC in static executable When --enable-static-pie is used to build static PIE, _DYNAMIC is used to compute the load address of static PIE. But _DYNAMIC is undefined when creating static executable. This patch makes _DYNAMIC weak in PIE libc.a so that it can be undefined. * sysdeps/i386/dl-machine.h (elf_machine_load_address): Allow undefined _DYNAMIC in PIE libc.a. * sysdeps/x86_64/dl-machine.h (elf_machine_load_address): Likewse. --- sysdeps/i386/dl-machine.h | 11 +++++++++-- sysdeps/x86_64/dl-machine.h | 11 +++++++++-- 2 files changed, 18 insertions(+), 4 deletions(-) (limited to 'sysdeps') diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h index 2e17eba..242c692 100644 --- a/sysdeps/i386/dl-machine.h +++ b/sysdeps/i386/dl-machine.h @@ -54,8 +54,15 @@ elf_machine_load_address (void) /* Compute the difference between the runtime address of _DYNAMIC as seen by a GOTOFF reference, and the link-time address found in the special unrelocated first GOT entry. */ - extern Elf32_Dyn bygotoff[] asm ("_DYNAMIC") attribute_hidden; - return (Elf32_Addr) &bygotoff - elf_machine_dynamic (); +#ifndef SHARED + extern Elf32_Dyn _DYNAMIC[] __attribute__((weak, visibility ("hidden"))); + if (!_DYNAMIC) + return 0; +#endif + /* The address of dynamic must be taken as non-weak to avoid dynamic + relocation. */ + extern Elf32_Dyn dynamic[] asm ("_DYNAMIC") attribute_hidden; + return (Elf32_Addr) &dynamic - elf_machine_dynamic (); } /* Set up the loaded object described by L so its unrelocated PLT diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h index 6a04cbc..a79e5ca 100644 --- a/sysdeps/x86_64/dl-machine.h +++ b/sysdeps/x86_64/dl-machine.h @@ -55,8 +55,15 @@ elf_machine_load_address (void) /* Compute the difference between the runtime address of _DYNAMIC as seen by an IP-relative reference, and the link-time address found in the special unrelocated first GOT entry. */ - extern ElfW(Dyn) _DYNAMIC[] attribute_hidden; - return (ElfW(Addr)) &_DYNAMIC - elf_machine_dynamic (); +#ifndef SHARED + extern ElfW(Dyn) _DYNAMIC[] __attribute__((weak, visibility ("hidden"))); + if (!_DYNAMIC) + return 0; +#endif + /* The address of dynamic must be taken as non-weak to avoid dynamic + relocation. */ + extern ElfW(Dyn) dynamic[] asm ("_DYNAMIC") attribute_hidden; + return (ElfW(Addr)) &dynamic - elf_machine_dynamic (); } /* Set up the loaded object described by L so its unrelocated PLT -- cgit v1.1