1 /* 2 * linux/arch/arm/include/asm/neon.h 3 * 4 * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 11 #include <asm/hwcap.h> 12 13 #define cpu_has_neon() (!!(elf_hwcap & HWCAP_NEON)) 14 15 #ifdef __ARM_NEON__ 16 17 /* 18 * If you are affected by the BUILD_BUG below, it probably means that you are 19 * using NEON code /and/ calling the kernel_neon_begin() function from the same 20 * compilation unit. To prevent issues that may arise from GCC reordering or 21 * generating(1) NEON instructions outside of these begin/end functions, the 22 * only supported way of using NEON code in the kernel is by isolating it in a 23 * separate compilation unit, and calling it from another unit from inside a 24 * kernel_neon_begin/kernel_neon_end pair. 25 * 26 * (1) Current GCC (4.7) might generate NEON instructions at O3 level if 27 * -mpfu=neon is set. 28 */ 29 30 #define kernel_neon_begin() \ 31 BUILD_BUG_ON_MSG(1, "kernel_neon_begin() called from NEON code") 32 33 #else 34 void kernel_neon_begin(void); 35 #endif 36 void kernel_neon_end(void); 37