FreeChainXenon/binutils-gdb
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions
94687 commits 2 branches 0 tags 423 MiB
Commit graph

3 commits

Author SHA1 Message Date
H.J. Lu
bd7ab16b45 x86-64: Generate branch with PLT32 relocation 
Since there is no need to prepare for PLT branch on x86-64, generate
R_X86_64_PLT32, instead of R_X86_64_PC32, if possible, which can be
used as a marker for 32-bit PC-relative branches.

To compile Linux kernel, this patch:

From: "H.J. Lu" <hjl.tools@gmail.com>
Subject: [PATCH] x86: Treat R_X86_64_PLT32 as R_X86_64_PC32

On i386, there are 2 types of PLTs, PIC and non-PIC.  PIE and shared
objects must use PIC PLT.  To use PIC PLT, you need to load
_GLOBAL_OFFSET_TABLE_ into EBX first.  There is no need for that on
x86-64 since x86-64 uses PC-relative PLT.

On x86-64, for 32-bit PC-relative branches, we can generate PLT32
relocation, instead of PC32 relocation, which can also be used as
a marker for 32-bit PC-relative branches.  Linker can always reduce
PLT32 relocation to PC32 if function is defined locally.   Local
functions should use PC32 relocation.  As far as Linux kernel is
concerned, R_X86_64_PLT32 can be treated the same as R_X86_64_PC32
since Linux kernel doesn't use PLT.

is needed.  It is available on hjl/plt32/master branch at

https://github.com/hjl-tools/linux

bfd/

	PR gas/22791
	* elf64-x86-64.c (is_32bit_relative_branch): Removed.
	(elf_x86_64_relocate_section): Check PIC relocations in PIE.
	Remove is_32bit_relative_branch usage.  Disallow PC32 reloc
	against protected function in shared object.

gas/

	PR gas/22791
	* config/tc-i386.c (need_plt32_p): New function.
	(output_jump): Generate BFD_RELOC_X86_64_PLT32 if possible.
	(md_estimate_size_before_relax): Likewise.
	* testsuite/gas/i386/reloc64.d: Updated.
	* testsuite/gas/i386/x86-64-jump.d: Likewise.
	* testsuite/gas/i386/x86-64-mpx-branch-1.d: Likewise.
	* testsuite/gas/i386/x86-64-mpx-branch-2.d: Likewise.
	* testsuite/gas/i386/x86-64-relax-2.d: Likewise.
	* testsuite/gas/i386/x86-64-relax-3.d: Likewise.
	* testsuite/gas/i386/ilp32/reloc64.d: Likewise.
	* testsuite/gas/i386/ilp32/x86-64-branch.d: Likewise.

ld/

	PR gas/22791
	* testsuite/ld-x86-64/mpx1c.rd: Updated.
	* testsuite/ld-x86-64/pr22791-1.err: New file.
	* testsuite/ld-x86-64/pr22791-1a.c: Likewise.
	* testsuite/ld-x86-64/pr22791-1b.s: Likewise.
	* testsuite/ld-x86-64/pr22791-2.rd: Likewise.
	* testsuite/ld-x86-64/pr22791-2a.s: Likewise.
	* testsuite/ld-x86-64/pr22791-2b.c: Likewise.
	* testsuite/ld-x86-64/pr22791-2c.s: Likewise.
	* testsuite/ld-x86-64/x86-64.exp: Run PR ld/22791 tests.
 2018-02-13 07:34:36 -08:00
Igor Zamyatin
d258b82828 Add -z bndplt to generate BND prefix in PLT entries 
This patch adds "-z bndplt" option Linux/x86-64 linker to generate BND
prefix in PLT entries.  It also updated Linux/x86-64 assembler not to
generate R_X86_64_PLT32_BND nor R_X86_64_PC32_BND relocations.

bfd/

2014-11-18  Igor Zamyatin  <igor.zamyatin@intel.com>

	* elf64-x86-64.c (elf_x86_64_check_relocs): Enable MPX PLT only
	for -z bndplt.

gas/

2014-11-18  Igor Zamyatin  <igor.zamyatin@intel.com>

	* config/tc-i386-intel.c (i386_operator): Remove last argument
	from lex_got call.
	* config/tc-i386.c (reloc): Remove bnd_prefix from parameters'
	list.  Return always BFD_RELOC_32_PCREL.
	* (output_branch): Remove condition for BFD_RELOC_X86_64_PC32_BND.
	* (output_jump): Update call to reloc accordingly.
	* (output_interseg_jump): Likewise.
	* (output_disp): Likewise.
	* (output_imm): Likewise.
	* (x86_cons_fix_new): Likewise.
	* (lex_got): Remove bnd_prefix from parameters' list in macro and
	declarations. Don't use BFD_RELOC_X86_64_PLT32_BND.
	* (x86_cons): Update call to lex_got accordingly.
	* (i386_immediate): Likewise.
	* (i386_displacement): Likewise.
	* (md_apply_fix): Don't use BFD_RELOC_X86_64_PLT32_BND nor
	BFD_RELOC_X86_64_PC32_BND.
	* (tc_gen_reloc): Likewise.

include/

2014-11-18  Igor Zamyatin  <igor.zamyatin@intel.com>

	* bfdlink.h (struct bfd_link_info): Add bndplt.

ld/

2014-11-18  Igor Zamyatin  <igor.zamyatin@intel.com>

	* emulparams/elf_x86_64.sh (BNDPLT): Set to yes for x86_64.
	* emultempl/elf32.em (gld${EMULATION_NAME}_handle_option): Handle
	"-z bndplt" if BNDPLT is yes.
	(gld${EMULATION_NAME}_list_options): Add "-z bndplt" entry.
	* ld.texinfo: Add description for bndplt.

ld/testsuite/

2014-11-18  Igor Zamyatin  <igor.zamyatin@intel.com>

	* testsuite/ld-x86-64/bnd-ifunc-1.d: Add bndplt option.
	* testsuite/ld-x86-64/bnd-ifunc-2.d: Likewise.
	* testsuite/ld-x86-64/bnd-plt-1.d: Likewise.  Update dissassembly
	sections.
	* testsuite/ld-x86-64/mpx.exp: Handle mpx3 and mpx4 tests.
	* testsuite/ld-x86-64/mpx1a.rd: Remove _BND from relocation name.
	* testsuite/ld-x86-64/mpx1c.rd: Likewise.
	* testsuite/ld-x86-64/mpx2a.rd: Likewise.
	* testsuite/ld-x86-64/mpx2c.rd: Likewise.
	* testsuite/ld-x86-64/mpx3.dd: New file.
	* testsuite/ld-x86-64/mpx3a.s: Likewise.
	* testsuite/ld-x86-64/mpx3b.s: Likewise.
	* testsuite/ld-x86-64/mpx4.dd: Likewise.
	* testsuite/ld-x86-64/mpx4a.s: Likewise.
	* testsuite/ld-x86-64/mpx4b.s: Likewise.
 2014-11-18 05:40:17 -08:00
H.J. Lu
c33205431a Add R_X86_64_PC32_BND and R_X86_64_PLT32_BND 
bfd/

	* elf64-x86-64.c (x86_64_elf_howto_table): Add R_X86_64_PC32_BND
	and R_X86_64_PLT32_BND.
	(R_X86_64_standard): Replace R_X86_64_RELATIVE64 with
	R_X86_64_PLT32_BND.
	(IS_X86_64_PCREL_TYPE): Add R_X86_64_PLT32_BND.
	(x86_64_reloc_map): Add BFD_RELOC_X86_64_PC32_BND and
	BFD_RELOC_X86_64_PLT32_BND.
	(elf_x86_64_check_relocs): Handle R_X86_64_PC32_BND and
	R_X86_64_PLT32_BND.
	(elf_x86_64_gc_sweep_hook): Likewise.
	(elf_x86_64_relocate_section): Likewise.
	* reloc.c (bfd_reloc_code_real): Add BFD_RELOC_X86_64_PC32_BND
	and BFD_RELOC_X86_64_PLT32_BND.
	* bfd-in2.h: Regenerated.
	* libbfd.h: Likewise.

gas/

	* config/tc-i386.c (reloc): Add an argument, bnd_prefix, to
	indicate if instruction has the BND prefix.  Return
	BFD_RELOC_X86_64_PC32_BND instead of BFD_RELOC_32_PCREL if
	bnd_prefix isn't zero.
	(output_branch): Pass BFD_RELOC_X86_64_PC32_BND to frag_var
	if needed.
	(output_jump): Update reloc call.
	(output_interseg_jump): Likewise.
	(output_disp): Likewise.
	(output_imm): Likewise.
	(x86_cons_fix_new): Likewise.
	(lex_got): Add an argument, bnd_prefix, to indicate if
	instruction has the BND prefix.  Use BFD_RELOC_X86_64_PLT32_BND
	if needed.
	(x86_cons): Update lex_got call.
	(i386_immediate): Likewise.
	(i386_displacement): Likewise.
	(md_apply_fix): Handle BFD_RELOC_X86_64_PC32_BND and
	BFD_RELOC_X86_64_PLT32_BND.
	(tc_gen_reloc): Likewise.
	* config/tc-i386-intel.c (i386_operator): Update lex_got call.

gas/testsuite/

	* gas/i386/i386.exp: Run x86-64-mpx-branch-1 and
	x86-64-mpx-branch-2 on 64-bit ELF targets.
	* gas/i386/x86-64-mpx-branch-1.d: New file.
	* gas/i386/x86-64-mpx-branch-1.s: Likewise.
	* gas/i386/x86-64-mpx-branch-2.d: Likewise.
	* gas/i386/x86-64-mpx-branch-2.s: Likewise.

include/elf/

	* x86-64.h: Add R_X86_64_PC32_BND and R_X86_64_PLT32_BND.

ld/testsuite/

	* ld-x86-64/mpx.exp: New file.
	* ld-x86-64/mpx1.out: Likewise.
	* ld-x86-64/mpx1a.c: Likewise.
	* ld-x86-64/mpx1a.rd: Likewise.
	* ld-x86-64/mpx1b.c: Likewise.
	* ld-x86-64/mpx1c.c: Likewise.
	* ld-x86-64/mpx1c.rd: Likewise.
 2013-11-17 08:57:56 -08:00