serenity/Libraries/LibELF/Arch/i386/plt_trampoline.S
Andrew Kaster 331f37d1a8 LibELF: Re-organize ELFDynamicObject::load and add PLT trampoline
ELFDynamicObject::load looks a lot better with all the steps
re-organized into helpers.

Add plt_trampoline.S to handle PLT fixups for lazy loading.
Add the needed trampoline-trampolines in ELFDynamicObject to get to
the proper relocations and to return the symbol back to the assembly
method to call into from the PLT once we return back to user code.
2020-01-01 23:54:06 +01:00

58 lines
2.2 KiB
ArmAsm

/*-
* Copyright (c) 1998, 2002 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas and by Charles M. Hannum.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/**
* This asm method is copied from NetBSD. We changed the internal method that
* gets called and the name, but it's still essentially the same as
* _rtld_bind_start from libexec/ld.elf_so/arch/i386/rtld_start.S
*/
.align 4
.globl _plt_trampoline
.hidden _plt_trampoline
.type _plt_trampoline,@function
_plt_trampoline: # (obj, reloff)
pushf # save registers
pushl %eax
pushl %ecx
pushl %edx
pushl 20(%esp) # Copy of reloff
pushl 20(%esp) # Copy of obj
call _fixup_plt_entry # Call the binder
addl $8,%esp # pop binder args
movl %eax,20(%esp) # Store function to be called in obj
popl %edx
popl %ecx
popl %eax
popf
leal 4(%esp),%esp # Discard reloff, do not change eflags
ret