1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * Start assembly for snippets 4 * 5 * Copyright (c) 2021 IBM Corp. 6 * 7 * Authors: 8 * Janosch Frank <frankja@linux.ibm.com> 9 */ 10#include <asm/sigp.h> 11 12.section .init 13 .globl start 14start: 15 larl %r1, initial_cr0 16 lctlg %c0, %c0, 0(%r1) 17 /* XOR all registers with themselves to clear them fully. */ 18 .irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 19 xgr \i,\i 20 .endr 21 /* 0x3000 is the stack page for now */ 22 lghi %r15, stackptr 23 sam64 24 brasl %r14, main 25 /* 26 * If main() returns, we stop the CPU with the code below. We also 27 * route some functions that are required by the libc (but not usable 28 * from snippets) to the CPU stop code below, so that snippets can 29 * still be linked against the libc code (to use non-related functions 30 * like memset() etc.) 31 */ 32.global puts 33.global exit 34puts: 35exit: 36 /* For now let's only use cpu 0 in snippets so this will always work. */ 37 xgr %r0, %r0 38 sigp %r2, %r0, SIGP_STOP 39 40initial_cr0: 41 /* enable AFP-register control, so FP regs (+BFP instr) can be used */ 42 .quad 0x0000000000040000 43