Browse Source
commit a7664973b2
Author: Jan Beulich <jbeulich@suse.com>
Date: Mon Apr 26 10:41:35 2021 +0200
x86: correct overflow checking for 16-bit PC-relative relocs
caused linker failure when building 16-bit program in a 32-bit ELF
container. Update GNU_PROPERTY_X86_FEATURE_2_USED with
#define GNU_PROPERTY_X86_FEATURE_2_CODE16 (1U << 12)
to indicate that 16-bit mode instructions are used in the input object:
https://groups.google.com/g/x86-64-abi/c/UvvXWeHIGMA
to indicate that 16-bit mode instructions are used in the object to
allow linker to properly perform relocation overflow check for 16-bit
PC-relative relocations in 16-bit mode instructions.
1. Update x86 assembler to always generate the GNU property note with
GNU_PROPERTY_X86_FEATURE_2_CODE16 for .code16 in ELF object.
2. Update i386 and x86-64 linkers to use 16-bit PC16 relocations if
input object is marked with GNU_PROPERTY_X86_FEATURE_2_CODE16.
bfd/
PR ld/27905
* elf32-i386.c: Include "libiberty.h".
(elf_howto_table): Add 16-bit R_386_PC16 entry.
(elf_i386_rtype_to_howto): Add a BFD argument. Use 16-bit
R_386_PC16 if input has 16-bit mode instructions.
(elf_i386_info_to_howto_rel): Update elf_i386_rtype_to_howto
call.
(elf_i386_tls_transition): Likewise.
(elf_i386_relocate_section): Likewise.
* elf64-x86-64.c (x86_64_elf_howto_table): Add 16-bit
R_X86_64_PC16 entry.
(elf_x86_64_rtype_to_howto): Use 16-bit R_X86_64_PC16 if input
has 16-bit mode instructions.
* elfxx-x86.c (_bfd_x86_elf_parse_gnu_properties): Set
elf_x86_has_code16 if relocatable input is marked with
GNU_PROPERTY_X86_FEATURE_2_CODE16.
* elfxx-x86.h (elf_x86_obj_tdata): Add has_code16.
(elf_x86_has_code16): New.
binutils/
PR ld/27905
* readelf.c (decode_x86_feature_2): Support
GNU_PROPERTY_X86_FEATURE_2_CODE16.
gas/
PR ld/27905
* config/tc-i386.c (set_code_flag): Update x86_feature_2_used
with GNU_PROPERTY_X86_FEATURE_2_CODE16 for .code16 in ELF
object.
(set_16bit_gcc_code_flag): Likewise.
(x86_cleanup): Always generate the GNU property note if
x86_feature_2_used isn't 0.
* testsuite/gas/i386/code16-2.d: New file.
* testsuite/gas/i386/code16-2.s: Likewise.
* testsuite/gas/i386/x86-64-code16-2.d: Likewise.
* testsuite/gas/i386/i386.exp: Run code16-2 and x86-64-code16-2.
include/
PR ld/27905
* elf/common.h (GNU_PROPERTY_X86_FEATURE_2_CODE16): New.
ld/
PR ld/27905
* testsuite/ld-i386/code16.d: New file.
* testsuite/ld-i386/code16.t: Likewise.
* testsuite/ld-x86-64/code16.d: Likewise.
* testsuite/ld-x86-64/code16.t: Likewise.
* testsuite/ld-i386/i386.exp: Run code16.
* testsuite/ld-x86-64/x86-64.exp: Likewise.
binutils-2_37-branch
H.J. Lu
5 years ago
22 changed files with 223 additions and 25 deletions
@ -0,0 +1,8 @@ |
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#name: i386 code16 2 |
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#as: -mx86-used-note=no --generate-missing-build-notes=no |
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#readelf: -n |
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Displaying notes found in: .note.gnu.property |
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[ ]+Owner[ ]+Data size[ ]+Description |
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GNU 0x[0-9a-f]+ NT_GNU_PROPERTY_TYPE_0 |
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Properties: x86 feature used: x86, CODE16 |
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@ -0,0 +1,10 @@ |
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.code16gcc |
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.text |
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.section .text.default_process_op.isra.0,"ax",@progbits |
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.type default_process_op.isra.0, @function |
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default_process_op.isra.0: |
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ret |
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.section .text.mpt_scsi_process_op,"ax",@progbits |
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.type mpt_scsi_process_op, @function |
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mpt_scsi_process_op: |
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jmp default_process_op.isra.0 |
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@ -0,0 +1,9 @@ |
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#source: code16-2.s |
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#name: x86-64 code16 2 |
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#as: -mx86-used-note=no --generate-missing-build-notes=no |
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#readelf: -n |
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|
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Displaying notes found in: .note.gnu.property |
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[ ]+Owner[ ]+Data size[ ]+Description |
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GNU 0x[0-9a-f]+ NT_GNU_PROPERTY_TYPE_0 |
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Properties: x86 feature used: x86, CODE16 |
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@ -0,0 +1,19 @@ |
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#name: i386 R_386_PC16 reloc in 16-bit mode |
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#as: --32 -mx86-used-note=no --generate-missing-build-notes=no |
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#source: ${srcdir}/../../../gas/testsuite/gas/i386/code16-2.s |
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#ld: -T code16.t |
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#objdump: -dw -Mi8086 |
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.*: +file format .* |
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Disassembly of section .text.default_process_op.isra.0: |
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0+737c <default_process_op.isra.0>: |
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+[a-f0-9]+: 66 c3 retl |
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Disassembly of section .text.mpt_scsi_process_op: |
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0+f869 <mpt_scsi_process_op>: |
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+[a-f0-9]+: e9 10 7b jmp 737c <default_process_op.isra.0> |
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#pass |
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@ -0,0 +1,7 @@ |
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OUTPUT_FORMAT("elf32-i386") |
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OUTPUT_ARCH("i386") |
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SECTIONS |
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{ |
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.text.default_process_op.isra.0 0x737c : { *(.text.default_process_op.isra.0) } |
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.text.mpt_scsi_process_op 0xf869 : { *(.text.mpt_scsi_process_op) } |
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} |
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@ -0,0 +1,19 @@ |
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#name: x86-64 R_X86_64_PC16 reloc in 16-bit mode |
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#as: --64 -mx86-used-note=no --generate-missing-build-notes=no |
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#source: ${srcdir}/../../../gas/testsuite/gas/i386/code16-2.s |
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#ld: -T code16.t |
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#objdump: -dw -Mi8086 |
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.*: +file format .* |
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Disassembly of section .text.default_process_op.isra.0: |
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0+737c <default_process_op.isra.0>: |
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+[a-f0-9]+: 66 c3 retl |
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Disassembly of section .text.mpt_scsi_process_op: |
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0+f869 <mpt_scsi_process_op>: |
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+[a-f0-9]+: e9 10 7b jmp 737c <default_process_op.isra.0> |
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#pass |
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@ -0,0 +1,7 @@ |
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OUTPUT_FORMAT("elf64-x86-64") |
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OUTPUT_ARCH("i386:x86-64") |
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SECTIONS |
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{ |
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.text.default_process_op.isra.0 0x737c : { *(.text.default_process_op.isra.0) } |
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.text.mpt_scsi_process_op 0xf869 : { *(.text.mpt_scsi_process_op) } |
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} |
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