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