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Add extern_protected_data and set it for x86

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Re-apply: commit ca3fe95e46

With copy relocation, address of protected data defined in the shared
library may be external.  This patch adds extern_protected_data and
changes _bfd_elf_symbol_refs_local_p to return false for protected data
if extern_protected_data is true.

This patch will break building shared libraries with protected data
symbols using GCCs older than GCC 5 without the bug fix for

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65248

GCC backport request should be made in the GCC bug report above.

To get correct run-time behavior on Linux, glibc 2.22 or above are
required, which have the bug fix for

https://sourceware.org/bugzilla/show_bug.cgi?id=17711

Backports for glibc 2.21, 2.20, 2.19 and 2.18 are on hjl/pr17711/2.21,
hjl/pr17711/2.20, hjl/pr17711/2.19 and hjl/pr17711/2.18 branches,
respectively, at

https://sourceware.org/git/?p=glibc.git;a=summary

bfd/

	PR ld/pr15228
	PR ld/pr17709
	* elf-bfd.h (elf_backend_data): Add extern_protected_data.
	* elf32-i386.c (elf_backend_extern_protected_data): New.
	Defined to 1.
	* elf64-x86-64.c (elf_backend_extern_protected_data): Likewise.
	* elflink.c (_bfd_elf_adjust_dynamic_copy): Don't error on
	copy relocs against protected symbols if extern_protected_data
	is true.
	(_bfd_elf_symbol_refs_local_p): Don't return true on protected
	non-function symbols if extern_protected_data is true.
	* elfxx-target.h (elf_backend_extern_protected_data): New.
	Default to 0.
	(elfNN_bed): Initialize extern_protected_data with
	elf_backend_extern_protected_data.

ld/testsuite/

	PR ld/pr15228
	PR ld/pr17709
	* ld-i386/i386.exp (i386tests): Add a test for PR ld/17709.
	* ld-i386/pr17709-nacl.rd: New file.
	* ld-i386/pr17709.rd: Likewise.
	* ld-i386/pr17709a.s: Likewise.
	* ld-i386/pr17709b.s: Likewise.
	* ld-i386/protected3.d: Updated.
	* ld-i386/protected3.s: Likewise.
	* ld-x86-64/pr17709-nacl.rd: New file.
	* ld-x86-64/pr17709.rd: Likewise.
	* ld-x86-64/pr17709a.s: Likewise.
	* ld-x86-64/pr17709b.s: Likewise.
	* ld-x86-64/protected3.d: Updated.
	* ld-x86-64/protected3.s: Likewise.
	* ld-x86-64/x86-64.exp (x86_64tests): Add a test for PR ld/17709.
This commit is contained in:
H.J. Lu
2015-03-05 06:34:39 -08:00
parent de3db44c87
commit f74839702e
21 changed files with 112 additions and 8 deletions
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9
bfd/elflink.c
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@@ -2673,7 +2673,9 @@ _bfd_elf_adjust_dynamic_copy (struct bfd_link_info *info,
/* Increment the size of DYNBSS to make room for the symbol. */
dynbss->size += h->size;
if (h->protected_def)
/* No error if extern_protected_data is true. */
if (h->protected_def
&& !get_elf_backend_data (dynbss->owner)->extern_protected_data)
info->callbacks->einfo
(_("%P: copy reloc against protected `%T' is dangerous\n"),
h->root.root.string);
@@ -2833,8 +2835,9 @@ _bfd_elf_symbol_refs_local_p (struct elf_link_hash_entry *h,
bed = get_elf_backend_data (hash_table->dynobj);
/* STV_PROTECTED non-function symbols are local. */
if (!bed->is_function_type (h->type))
/* If extern_protected_data is false, STV_PROTECTED non-function
symbols are local. */
if (!bed->extern_protected_data && !bed->is_function_type (h->type))
return TRUE;
/* Function pointer equality tests may require that STV_PROTECTED