Ard Biesheuvel | 73c132c | 2013-05-16 11:41:48 +0200 | [diff] [blame] | 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); |