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/* Copyright 2020-2024 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <asm/unistd.h>
/* Define these for each architecture:
1) RETURN_ADDRESS_REGNO: The register number representing the return
address in the DWARF CFI. It can be easily be looked up using
`readelf --debug-dump=frames-interp` on an existing binary of that
architecture, where it says `ra=X`.
2) exit_0: a sequence of instruction to execute the exit syscall with
argument 0. */
#if defined(__x86_64__)
# define RETURN_ADDRESS_REGNO 16
.macro exit_0
mov $__NR_exit, %rax
mov $0, %rdi
syscall
.endm
#elif defined(__i386__)
# define RETURN_ADDRESS_REGNO 8
.macro exit_0
mov $__NR_exit, %eax
mov $0, %ebx
int $0x80
.endm
#elif defined(__aarch64__)
# define RETURN_ADDRESS_REGNO 30
.macro exit_0
mov x0, #0
mov x8, #__NR_exit
svc #0
.endm
#elif defined(__arm__)
# define RETURN_ADDRESS_REGNO 14
.macro exit_0
ldr r7, =__NR_exit
ldr r0, =0
swi 0x0
.endm
#elif defined __powerpc64__
# define RETURN_ADDRESS_REGNO 65
.macro exit_0
li 0, __NR_exit /* r0 - contains system call number */
li 3, 0 /* r3 - contains first argument for sys call */
sc
.endm
#else
# error "Unsupported architecture"
#endif
/* The following assembly program mimics this pseudo C program, where
everything has been inlined:
1 void bar(void) {
2 nop;
3 }
4
5 void foo(void) {
6 nop;
7 bar();
8 nop;
9 }
10
11 void _start(void) {
12 nop;
13 foo();
14 nop;
15 exit(0);
16 }
*/
#if defined __powerpc64__
# if _CALL_ELF == 2
.abiversion 2 /* Tell gdb what ELF version to use. */
.global _start
_start:
# else
.abiversion 1 /* Tell gdb what ELF version to use. */
.align 2
.global _start
.section ".opd", "aw"
.align 3
_start:
.quad ._start,.TOC.@tocbase,0
.previous
.type ._start,@function
._start:
# endif
#else
.global _start
_start:
#endif
.cfi_startproc
/* State that the return address for this frame is undefined. */
.cfi_undefined RETURN_ADDRESS_REGNO
.global __cu_low_pc
__cu_low_pc:
.global __start_low_pc
__start_low_pc:
/* Line 12 */
nop
.global __foo_low_pc
__foo_low_pc:
/* Line 6 */
nop
.global __bar_low_pc
__bar_low_pc:
/* Line 2 */
nop
.global __bar_high_pc
__bar_high_pc:
/* Line 8 */
nop
.global __foo_high_pc
__foo_high_pc:
/* Line 14 */
nop
/* Line 15 */
exit_0
.cfi_endproc
.global __start_high_pc
__start_high_pc:
.global __cu_high_pc
__cu_high_pc:
#ifdef __arm__
.section .note.GNU-stack,"",%progbits
#else
.section .note.GNU-stack,"",@progbits
#endif
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