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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.
This commit is contained in:
H.J. Lu 2017-09-28 15:28:00 -07:00
parent 4d3693ec1c
commit 4088d8dd29
3 changed files with 25 additions and 4 deletions
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7
ChangeLog
View File

@ -1,3 +1,10 @@
2017-09-28 H.J. Lu <hongjiu.lu@intel.com>
* 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.
2017-09-28 Wilco Dijkstra <wdijkstr@arm.com> 2017-09-28 Wilco Dijkstra <wdijkstr@arm.com>
* sysdeps/alpha/fpu/bits/mathinline.h: Delete file. * sysdeps/alpha/fpu/bits/mathinline.h: Delete file.

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

@ -54,8 +54,15 @@ elf_machine_load_address (void)
/* Compute the difference between the runtime address of _DYNAMIC as seen /* Compute the difference between the runtime address of _DYNAMIC as seen
by a GOTOFF reference, and the link-time address found in the special by a GOTOFF reference, and the link-time address found in the special
unrelocated first GOT entry. */ unrelocated first GOT entry. */
extern Elf32_Dyn bygotoff[] asm ("_DYNAMIC") attribute_hidden; #ifndef SHARED
return (Elf32_Addr) &bygotoff - elf_machine_dynamic (); 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 /* Set up the loaded object described by L so its unrelocated PLT

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

@ -55,8 +55,15 @@ elf_machine_load_address (void)
/* Compute the difference between the runtime address of _DYNAMIC as seen /* Compute the difference between the runtime address of _DYNAMIC as seen
by an IP-relative reference, and the link-time address found in the by an IP-relative reference, and the link-time address found in the
special unrelocated first GOT entry. */ special unrelocated first GOT entry. */
extern ElfW(Dyn) _DYNAMIC[] attribute_hidden; #ifndef SHARED
return (ElfW(Addr)) &_DYNAMIC - elf_machine_dynamic (); 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 /* Set up the loaded object described by L so its unrelocated PLT