1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * linux/arch/arm/include/asm/neon.h 4 * 5 * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org> 6 */ 7 8 #include <asm/hwcap.h> 9 10 #define cpu_has_neon() (!!(elf_hwcap & HWCAP_NEON)) 11 12 #ifdef __ARM_NEON__ 13 14 /* 15 * If you are affected by the BUILD_BUG below, it probably means that you are 16 * using NEON code /and/ calling the kernel_neon_begin() function from the same 17 * compilation unit. To prevent issues that may arise from GCC reordering or 18 * generating(1) NEON instructions outside of these begin/end functions, the 19 * only supported way of using NEON code in the kernel is by isolating it in a 20 * separate compilation unit, and calling it from another unit from inside a 21 * kernel_neon_begin/kernel_neon_end pair. 22 * 23 * (1) Current GCC (4.7) might generate NEON instructions at O3 level if 24 * -mpfu=neon is set. 25 */ 26 27 #define kernel_neon_begin() \ 28 BUILD_BUG_ON_MSG(1, "kernel_neon_begin() called from NEON code") 29 30 #else 31 void kernel_neon_begin(void); 32 #endif 33 void kernel_neon_end(void); 34