za-fork-asm.S (979B)
1// SPDX-License-Identifier: GPL-2.0-only 2// Copyright (C) 2021 ARM Limited. 3 4#include "sme-inst.h" 5 6.arch_extension sve 7 8#define MAGIC 42 9 10#define MAXVL 2048 11#define MAXVL_B (MAXVL / 8) 12 13.pushsection .text 14.data 15.align 4 16scratch: 17 .space MAXVL_B 18.popsection 19 20.globl fork_test 21fork_test: 22 smstart_za 23 24 // For simplicity just set one word in one vector, other tests 25 // cover general data corruption issues. 26 ldr x0, =scratch 27 mov x1, #MAGIC 28 str x1, [x0] 29 mov w12, wzr 30 _ldr_za 12, 0 // ZA.H[W12] loaded from [X0] 31 32 // Tail call into the C portion that does the fork & verify 33 b fork_test_c 34 35.globl verify_fork 36verify_fork: 37 // SVCR should have ZA=1, SM=0 38 mrs x0, S3_3_C4_C2_2 39 and x1, x0, #3 40 cmp x1, #2 41 beq 1f 42 mov x0, xzr 43 b 100f 441: 45 46 // ZA should still have the value we loaded 47 ldr x0, =scratch 48 mov w12, wzr 49 _str_za 12, 0 // ZA.H[W12] stored to [X0] 50 ldr x1, [x0] 51 cmp x1, #MAGIC 52 beq 2f 53 mov x0, xzr 54 b 100f 55 562: 57 // All tests passed 58 mov x0, #1 59100: 60 ret 61