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73c132c1 AB |
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); |