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Intel Control-flow Enforcement Technology (CET) instructions: https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-en forcement-technology-preview.pdf includes Indirect Branch Tracking (IBT) and Shadow Stack (SHSTK). GNU_PROPERTY_X86_FEATURE_1_IBT is added to GNU program property to indicate that all executable sections are compatible with IBT when ENDBR instruction starts each valid target where an indirect branch instruction can land. Linker sets GNU_PROPERTY_X86_FEATURE_1_IBT on output only if it is set on all relocatable inputs. On an IBT capable processor, the following steps should be taken: 1. When loading an executable without an interpreter, enable IBT and lock IBT if GNU_PROPERTY_X86_FEATURE_1_IBT is set on the executable. 2. When loading an executable with an interpreter, enable IBT if GNU_PROPERTY_X86_FEATURE_1_IBT is set on the interpreter. a. If GNU_PROPERTY_X86_FEATURE_1_IBT isn't set on the executable, disable IBT. b. Lock IBT. 3. If IBT is enabled, when loading a shared object without GNU_PROPERTY_X86_FEATURE_1_IBT: a. If legacy interwork is allowed, then mark all pages in executable PT_LOAD segments in legacy code page bitmap. Failure of legacy code page bitmap allocation causes an error. b. If legacy interwork isn't allowed, it causes an error. GNU_PROPERTY_X86_FEATURE_1_SHSTK is added to GNU program property to indicate that all executable sections are compatible with SHSTK where return address popped from shadow stack always matches return address popped from normal stack. Linker sets GNU_PROPERTY_X86_FEATURE_1_SHSTK on output only if it is set on all relocatable inputs. On a SHSTK capable processor, the following steps should be taken: 1. When loading an executable without an interpreter, enable SHSTK if GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on the executable. 2. When loading an executable with an interpreter, enable SHSTK if GNU_PROPERTY_X86_FEATURE_1_SHSTK is set on interpreter. a. If GNU_PROPERTY_X86_FEATURE_1_SHSTK isn't set on the executable or any shared objects loaded via the DT_NEEDED tag, disable SHSTK. b. Otherwise lock SHSTK. 3. After SHSTK is enabled, it is an error to load a shared object without GNU_PROPERTY_X86_FEATURE_1_SHSTK. To enable CET support in glibc, --enable-cet is required to configure glibc. When CET is enabled, both compiler and assembler must support CET. Otherwise, it is a configure-time error. To support CET run-time control, 1. _dl_x86_feature_1 is added to the writable ld.so namespace to indicate if IBT or SHSTK are enabled at run-time. It should be initialized by init_cpu_features. 2. For dynamic executables: a. A l_cet field is added to struct link_map to indicate if IBT or SHSTK is enabled in an ELF module. _dl_process_pt_note or _rtld_process_pt_note is called to process PT_NOTE segment for GNU program property and set l_cet. b. _dl_open_check is added to check IBT and SHSTK compatibilty when dlopening a shared object. 3. Replace i386 _dl_runtime_resolve and _dl_runtime_profile with _dl_runtime_resolve_shstk and _dl_runtime_profile_shstk, respectively if SHSTK is enabled. CET run-time control can be changed via GLIBC_TUNABLES with $ export GLIBC_TUNABLES=glibc.tune.x86_shstk=[permissive|on|off] $ export GLIBC_TUNABLES=glibc.tune.x86_ibt=[permissive|on|off] 1. permissive: SHSTK is disabled when dlopening a legacy ELF module. 2. on: IBT or SHSTK are always enabled, regardless if there are IBT or SHSTK bits in GNU program property. 3. off: IBT or SHSTK are always disabled, regardless if there are IBT or SHSTK bits in GNU program property. <cet.h> from CET-enabled GCC is automatically included by assembly codes to add GNU_PROPERTY_X86_FEATURE_1_IBT and GNU_PROPERTY_X86_FEATURE_1_SHSTK to GNU program property. _CET_ENDBR is added at the entrance of all assembly functions whose address may be taken. _CET_NOTRACK is used to insert NOTRACK prefix with indirect jump table to support IBT. It is defined as notrack when _CET_NOTRACK is defined in <cet.h>. [BZ #21598] * configure.ac: Add --enable-cet. * configure: Regenerated. * elf/Makefille (all-built-dso): Add a comment. * elf/dl-load.c (filebuf): Moved before "dynamic-link.h". Include <dl-prop.h>. (_dl_map_object_from_fd): Call _dl_process_pt_note on PT_NOTE segment. * elf/dl-open.c: Include <dl-prop.h>. (dl_open_worker): Call _dl_open_check. * elf/rtld.c: Include <dl-prop.h>. (dl_main): Call _rtld_process_pt_note on PT_NOTE segment. Call _rtld_main_check. * sysdeps/generic/dl-prop.h: New file. * sysdeps/i386/dl-cet.c: Likewise. * sysdeps/unix/sysv/linux/x86/cpu-features.c: Likewise. * sysdeps/unix/sysv/linux/x86/dl-cet.h: Likewise. * sysdeps/x86/cet-tunables.h: Likewise. * sysdeps/x86/check-cet.awk: Likewise. * sysdeps/x86/configure: Likewise. * sysdeps/x86/configure.ac: Likewise. * sysdeps/x86/dl-cet.c: Likewise. * sysdeps/x86/dl-procruntime.c: Likewise. * sysdeps/x86/dl-prop.h: Likewise. * sysdeps/x86/libc-start.h: Likewise. * sysdeps/x86/link_map.h: Likewise. * sysdeps/i386/dl-trampoline.S (_dl_runtime_resolve): Add _CET_ENDBR. (_dl_runtime_profile): Likewise. (_dl_runtime_resolve_shstk): New. (_dl_runtime_profile_shstk): Likewise. * sysdeps/linux/x86/Makefile (sysdep-dl-routines): Add dl-cet if CET is enabled. (CFLAGS-.o): Add -fcf-protection if CET is enabled. (CFLAGS-.os): Likewise. (CFLAGS-.op): Likewise. (CFLAGS-.oS): Likewise. (asm-CPPFLAGS): Add -fcf-protection -include cet.h if CET is enabled. (tests-special): Add $(objpfx)check-cet.out. (cet-built-dso): New. (+$(cet-built-dso:=.note)): Likewise. (common-generated): Add $(cet-built-dso:$(common-objpfx)%=%.note). ($(objpfx)check-cet.out): New. (generated): Add check-cet.out. * sysdeps/x86/cpu-features.c: Include <dl-cet.h> and <cet-tunables.h>. (TUNABLE_CALLBACK (set_x86_ibt)): New prototype. (TUNABLE_CALLBACK (set_x86_shstk)): Likewise. (init_cpu_features): Call get_cet_status to check CET status and update dl_x86_feature_1 with CET status. Call TUNABLE_CALLBACK (set_x86_ibt) and TUNABLE_CALLBACK (set_x86_shstk). Disable and lock CET in libc.a. * sysdeps/x86/cpu-tunables.c: Include <cet-tunables.h>. (TUNABLE_CALLBACK (set_x86_ibt)): New function. (TUNABLE_CALLBACK (set_x86_shstk)): Likewise. * sysdeps/x86/sysdep.h (_CET_NOTRACK): New. (_CET_ENDBR): Define if not defined. (ENTRY): Add _CET_ENDBR. * sysdeps/x86/dl-tunables.list (glibc.tune): Add x86_ibt and x86_shstk. * sysdeps/x86_64/dl-trampoline.h (_dl_runtime_resolve): Add _CET_ENDBR. (_dl_runtime_profile): Likewise.
288 lines
7.7 KiB
ArmAsm
288 lines
7.7 KiB
ArmAsm
/* PLT trampolines. i386 version.
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Copyright (C) 2004-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include <link-defines.h>
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#ifdef HAVE_MPX_SUPPORT
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# define PRESERVE_BND_REGS_PREFIX bnd
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#else
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# define PRESERVE_BND_REGS_PREFIX .byte 0xf2
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#endif
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.text
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.globl _dl_runtime_resolve
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.type _dl_runtime_resolve, @function
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cfi_startproc
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.align 16
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_dl_runtime_resolve:
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cfi_adjust_cfa_offset (8)
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_CET_ENDBR
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pushl %eax # Preserve registers otherwise clobbered.
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cfi_adjust_cfa_offset (4)
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pushl %ecx
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cfi_adjust_cfa_offset (4)
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pushl %edx
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cfi_adjust_cfa_offset (4)
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movl 16(%esp), %edx # Copy args pushed by PLT in register. Note
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movl 12(%esp), %eax # that `fixup' takes its parameters in regs.
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call _dl_fixup # Call resolver.
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popl %edx # Get register content back.
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cfi_adjust_cfa_offset (-4)
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movl (%esp), %ecx
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movl %eax, (%esp) # Store the function address.
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movl 4(%esp), %eax
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ret $12 # Jump to function address.
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cfi_endproc
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.size _dl_runtime_resolve, .-_dl_runtime_resolve
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# The SHSTK compatible version.
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.text
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.globl _dl_runtime_resolve_shstk
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.type _dl_runtime_resolve_shstk, @function
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cfi_startproc
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.align 16
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_dl_runtime_resolve_shstk:
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cfi_adjust_cfa_offset (8)
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_CET_ENDBR
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pushl %eax # Preserve registers otherwise clobbered.
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cfi_adjust_cfa_offset (4)
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pushl %edx
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cfi_adjust_cfa_offset (4)
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movl 12(%esp), %edx # Copy args pushed by PLT in register. Note
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movl 8(%esp), %eax # that `fixup' takes its parameters in regs.
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call _dl_fixup # Call resolver.
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movl (%esp), %edx # Get register content back.
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movl %eax, %ecx # Store the function address.
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movl 4(%esp), %eax # Get register content back.
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addl $16, %esp # Adjust stack: PLT1 + PLT2 + %eax + %edx
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cfi_adjust_cfa_offset (-16)
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jmp *%ecx # Jump to function address.
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cfi_endproc
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.size _dl_runtime_resolve_shstk, .-_dl_runtime_resolve_shstk
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#ifndef PROF
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# The SHSTK compatible version.
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.globl _dl_runtime_profile_shstk
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.type _dl_runtime_profile_shstk, @function
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cfi_startproc
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.align 16
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_dl_runtime_profile_shstk:
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cfi_adjust_cfa_offset (8)
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_CET_ENDBR
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pushl %esp
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cfi_adjust_cfa_offset (4)
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addl $8, (%esp) # Account for the pushed PLT data
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pushl %ebp
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cfi_adjust_cfa_offset (4)
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pushl %eax # Preserve registers otherwise clobbered.
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cfi_adjust_cfa_offset (4)
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pushl %ecx
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cfi_adjust_cfa_offset (4)
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pushl %edx
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cfi_adjust_cfa_offset (4)
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movl %esp, %ecx
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subl $8, %esp
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cfi_adjust_cfa_offset (8)
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movl $-1, 4(%esp)
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leal 4(%esp), %edx
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movl %edx, (%esp)
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pushl %ecx # Address of the register structure
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cfi_adjust_cfa_offset (4)
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movl 40(%esp), %ecx # Load return address
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movl 36(%esp), %edx # Copy args pushed by PLT in register. Note
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movl 32(%esp), %eax # that `fixup' takes its parameters in regs.
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call _dl_profile_fixup # Call resolver.
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cfi_adjust_cfa_offset (-8)
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movl (%esp), %edx
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testl %edx, %edx
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jns 1f
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movl 4(%esp), %edx # Get register content back.
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movl %eax, %ecx # Store the function address.
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movl 12(%esp), %eax # Get register content back.
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# Adjust stack: PLT1 + PLT2 + %esp + %ebp + %eax + %ecx + %edx
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# + free.
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addl $32, %esp
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cfi_adjust_cfa_offset (-32)
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jmp *%ecx # Jump to function address.
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cfi_endproc
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.size _dl_runtime_profile_shstk, .-_dl_runtime_profile_shstk
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.globl _dl_runtime_profile
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.type _dl_runtime_profile, @function
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cfi_startproc
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.align 16
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_dl_runtime_profile:
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cfi_adjust_cfa_offset (8)
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_CET_ENDBR
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pushl %esp
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cfi_adjust_cfa_offset (4)
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addl $8, (%esp) # Account for the pushed PLT data
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pushl %ebp
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cfi_adjust_cfa_offset (4)
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pushl %eax # Preserve registers otherwise clobbered.
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cfi_adjust_cfa_offset (4)
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pushl %ecx
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cfi_adjust_cfa_offset (4)
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pushl %edx
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cfi_adjust_cfa_offset (4)
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movl %esp, %ecx
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subl $8, %esp
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cfi_adjust_cfa_offset (8)
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movl $-1, 4(%esp)
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leal 4(%esp), %edx
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movl %edx, (%esp)
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pushl %ecx # Address of the register structure
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cfi_adjust_cfa_offset (4)
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movl 40(%esp), %ecx # Load return address
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movl 36(%esp), %edx # Copy args pushed by PLT in register. Note
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movl 32(%esp), %eax # that `fixup' takes its parameters in regs.
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call _dl_profile_fixup # Call resolver.
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cfi_adjust_cfa_offset (-8)
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movl (%esp), %edx
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testl %edx, %edx
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jns 1f
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popl %edx
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cfi_adjust_cfa_offset (-4)
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popl %edx # Get register content back.
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cfi_adjust_cfa_offset (-4)
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movl (%esp), %ecx
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movl %eax, (%esp) # Store the function address.
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movl 4(%esp), %eax
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ret $20 # Jump to function address.
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/*
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+32 return address
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+28 PLT1
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+24 PLT2
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+20 %esp
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+16 %ebp
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+12 %eax
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+8 %ecx
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+4 %edx
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%esp free
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*/
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cfi_adjust_cfa_offset (8)
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1: movl %ebx, (%esp)
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cfi_rel_offset (ebx, 0)
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movl %edx, %ebx # This is the frame buffer size
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pushl %edi
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cfi_adjust_cfa_offset (4)
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cfi_rel_offset (edi, 0)
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pushl %esi
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cfi_adjust_cfa_offset (4)
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cfi_rel_offset (esi, 0)
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leal 44(%esp), %esi
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movl %ebx, %ecx
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orl $4, %ebx # Increase frame size if necessary to align
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# stack for the function call
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andl $~3, %ebx
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movl %esp, %edi
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subl %ebx, %edi
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movl %esp, %ebx
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cfi_def_cfa_register (ebx)
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movl %edi, %esp
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shrl $2, %ecx
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rep
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movsl
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movl (%ebx), %esi
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cfi_restore (esi)
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movl 4(%ebx), %edi
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cfi_restore (edi)
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/*
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%ebx+40 return address
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%ebx+36 PLT1
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%ebx+32 PLT2
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%ebx+28 %esp
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%ebx+24 %ebp
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%ebx+20 %eax
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%ebx+16 %ecx
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%ebx+12 %edx
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%ebx+8 %ebx
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%ebx+4 free
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%ebx free
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%esp copied stack frame
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*/
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movl %eax, (%ebx)
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movl 12(%ebx), %edx
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movl 16(%ebx), %ecx
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movl 20(%ebx), %eax
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call *(%ebx)
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movl %ebx, %esp
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cfi_def_cfa_register (esp)
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movl 8(%esp), %ebx
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cfi_restore (ebx)
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/*
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+40 return address
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+36 PLT1
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+32 PLT2
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+28 %esp
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+24 %ebp
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+20 %eax
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+16 %ecx
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+12 %edx
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+8 free
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+4 free
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%esp free
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*/
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#if LONG_DOUBLE_SIZE != 12
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# error "long double size must be 12 bytes"
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#endif
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# Allocate space for La_i86_retval and subtract 12 free bytes.
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subl $(LRV_SIZE - 12), %esp
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cfi_adjust_cfa_offset (LRV_SIZE - 12)
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movl %eax, LRV_EAX_OFFSET(%esp)
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movl %edx, LRV_EDX_OFFSET(%esp)
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fstpt LRV_ST0_OFFSET(%esp)
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fstpt LRV_ST1_OFFSET(%esp)
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#ifdef HAVE_MPX_SUPPORT
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bndmov %bnd0, LRV_BND0_OFFSET(%esp)
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bndmov %bnd1, LRV_BND1_OFFSET(%esp)
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#else
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.byte 0x66,0x0f,0x1b,0x44,0x24,LRV_BND0_OFFSET
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.byte 0x66,0x0f,0x1b,0x4c,0x24,LRV_BND1_OFFSET
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#endif
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pushl %esp
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cfi_adjust_cfa_offset (4)
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# Address of La_i86_regs area.
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leal (LRV_SIZE + 4)(%esp), %ecx
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# PLT2
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movl (LRV_SIZE + 4 + LR_SIZE)(%esp), %eax
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# PLT1
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movl (LRV_SIZE + 4 + LR_SIZE + 4)(%esp), %edx
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call _dl_call_pltexit
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movl LRV_EAX_OFFSET(%esp), %eax
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movl LRV_EDX_OFFSET(%esp), %edx
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fldt LRV_ST1_OFFSET(%esp)
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fldt LRV_ST0_OFFSET(%esp)
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#ifdef HAVE_MPX_SUPPORT
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bndmov LRV_BND0_OFFSET(%esp), %bnd0
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bndmov LRV_BND1_OFFSET(%esp), %bnd1
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#else
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.byte 0x66,0x0f,0x1a,0x44,0x24,LRV_BND0_OFFSET
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.byte 0x66,0x0f,0x1a,0x4c,0x24,LRV_BND1_OFFSET
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#endif
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# Restore stack before return.
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addl $(LRV_SIZE + 4 + LR_SIZE + 4), %esp
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cfi_adjust_cfa_offset (-(LRV_SIZE + 4 + LR_SIZE + 4))
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PRESERVE_BND_REGS_PREFIX
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ret
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cfi_endproc
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.size _dl_runtime_profile, .-_dl_runtime_profile
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#endif
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