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Revert x86: Allow undefined _DYNAMIC in static executable

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This code is used in non-PIE static executable and static PIE.  It checks
if _DYNAMIC is undefined before using it to compute load address.  But
not all targets can convert access _DYNAMIC via GOT, which needs dynamic
relocation, to PC-relative at link-time.

	* sysdeps/i386/dl-machine.h (elf_machine_load_address): Don't
	allow undefined _DYNAMIC in PIE libc.a.
	* sysdeps/x86_64/dl-machine.h (elf_machine_load_address):
	Likewse.
This commit is contained in:
H.J. Lu 2017-10-03 17:48:55 -07:00
parent 0c609d19e3
commit 02d2d8927d
3 changed files with 11 additions and 18 deletions
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7
ChangeLog
View File

@ -1,3 +1,10 @@
2017-10-03 H.J. Lu <hongjiu.lu@intel.com>
* sysdeps/i386/dl-machine.h (elf_machine_load_address): Don't
allow undefined _DYNAMIC in PIE libc.a.
* sysdeps/x86_64/dl-machine.h (elf_machine_load_address):
Likewse.
2017-10-03 H.J. Lu <hongjiu.lu@intel.com>
* sysdeps/mips/dl-machine.h (elf_machine_load_address): Don't

11
sysdeps/i386/dl-machine.h
View File

@ -54,15 +54,8 @@ 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. */
#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 ();
extern Elf32_Dyn bygotoff[] asm ("_DYNAMIC") attribute_hidden;
return (Elf32_Addr) &bygotoff - elf_machine_dynamic ();
}
/* Set up the loaded object described by L so its unrelocated PLT

11
sysdeps/x86_64/dl-machine.h
View File

@ -55,15 +55,8 @@ 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. */
#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 ();
extern ElfW(Dyn) _DYNAMIC[] attribute_hidden;
return (ElfW(Addr)) &_DYNAMIC - elf_machine_dynamic ();
}
/* Set up the loaded object described by L so its unrelocated PLT