1 /* Machine-dependent ELF dynamic relocation inline functions.  x32 version.
2    Copyright (C) 2012-2021 Free Software Foundation, Inc.
3    This file is part of the GNU C Library.
4 
5    The GNU C Library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Lesser General Public
7    License as published by the Free Software Foundation; either
8    version 2.1 of the License, or (at your option) any later version.
9 
10    The GNU C Library is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13    Lesser General Public License for more details.
14 
15    You should have received a copy of the GNU Lesser General Public
16    License along with the GNU C Library; if not, see
17    <https://www.gnu.org/licenses/>.  */
18 
19 /* Must allow <sysdeps/x86_64/dl-machine.h> to be included more than once.
20    See #ifdef RESOLVE_MAP in sysdeps/x86_64/dl-machine.h.  */
21 #include <sysdeps/x86_64/dl-machine.h>
22 
23 #ifndef _X32_DL_MACHINE_H
24 #define _X32_DL_MACHINE_H
25 
26 #undef ARCH_LA_PLTENTER
27 #undef ARCH_LA_PLTEXIT
28 #undef RTLD_START
29 
30 /* Names of the architecture-specific auditing callback functions.  */
31 #define ARCH_LA_PLTENTER x32_gnu_pltenter
32 #define ARCH_LA_PLTEXIT x32_gnu_pltexit
33 
34 /* Initial entry point code for the dynamic linker.
35    The C function `_dl_start' is the real entry point;
36    its return value is the user program's entry point.  */
37 #define RTLD_START asm ("\n\
38 .text\n\
39 	.p2align 4\n\
40 .globl _start\n\
41 .globl _dl_start_user\n\
42 _start:\n\
43 	movl %esp, %edi\n\
44 	call _dl_start\n\
45 _dl_start_user:\n\
46 	# Save the user entry point address in %r12.\n\
47 	movl %eax, %r12d\n\
48 	# See if we were run as a command with the executable file\n\
49 	# name as an extra leading argument.\n\
50 	movl _dl_skip_args(%rip), %eax\n\
51 	# Pop the original argument count.\n\
52 	movl (%rsp), %edx\n\
53 	# Adjust the stack pointer to skip _dl_skip_args words.\n\
54 	lea 4(%rsp,%rax,4), %esp\n\
55 	# Subtract _dl_skip_args from argc.\n\
56 	subl %eax, %edx\n\
57 	# Push argc back on the stack.\n\
58 	subl $4, %esp\n\
59 	movl %edx, (%rsp)\n\
60 	# Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env)\n\
61 	# argc -> rsi\n\
62 	movl %edx, %esi\n\
63 	# Save %rsp value in %r13.\n\
64 	movl %esp, %r13d\n\
65 	# And align stack for the _dl_init call.\n\
66 	and $-16, %esp\n\
67 	# _dl_loaded -> rdi\n\
68 	movl _rtld_local(%rip), %edi\n\
69 	# env -> rcx\n\
70 	lea 8(%r13,%rdx,4), %ecx\n\
71 	# argv -> rdx\n\
72 	lea 4(%r13), %edx\n\
73 	# Clear %rbp to mark outermost frame obviously even for constructors.\n\
74 	xorl %ebp, %ebp\n\
75 	# Call the function to run the initializers.\n\
76 	call _dl_init\n\
77 	# Pass our finalizer function to the user in %rdx, as per ELF ABI.\n\
78 	lea _dl_fini(%rip), %edx\n\
79 	# And make sure %rsp points to argc stored on the stack.\n\
80 	movl %r13d, %esp\n\
81 	# Jump to the user's entry point.\n\
82 	jmp *%r12\n\
83 .previous\n\
84 ");
85 
86 #endif /* !_X32_DL_MACHINE_H */
87