1 // SPDX-License-Identifier: GPL-2.0+
2
3 /*
4 * Part of fork context switch microbenchmark.
5 *
6 * Copyright 2018, Anton Blanchard, IBM Corp.
7 */
8
9 #define _GNU_SOURCE
10 #include <sys/syscall.h>
11
_start(void)12 void _start(void)
13 {
14 asm volatile (
15 "li %%r0, %[sys_exit];"
16 "li %%r3, 0;"
17 "sc;"
18 :
19 : [sys_exit] "i" (SYS_exit)
20 /*
21 * "sc" will clobber r0, r3-r13, cr0, ctr, xer and memory.
22 * Even though sys_exit never returns, handle clobber
23 * registers.
24 */
25 : "r0", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10",
26 "r11", "r12", "r13", "cr0", "ctr", "xer", "memory"
27 );
28 }
29