cregit-Linux how code gets into the kernel

Release 4.9 lib/raid6/neon.c

Directory: lib/raid6
/*
 * linux/lib/raid6/neon.c - RAID6 syndrome calculation using ARM NEON intrinsics
 *
 * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/raid/pq.h>

#ifdef __KERNEL__
#include <asm/neon.h>
#else

#define kernel_neon_begin()

#define kernel_neon_end()

#define cpu_has_neon()		(1)
#endif

/*
 * There are 2 reasons these wrappers are kept in a separate compilation unit
 * from the actual implementations in neonN.c (generated from neon.uc by
 * unroll.awk):
 * - the actual implementations use NEON intrinsics, and the GCC support header
 *   (arm_neon.h) is not fully compatible (type wise) with the kernel;
 * - the neonN.c files are compiled with -mfpu=neon and optimization enabled,
 *   and we have to make sure that we never use *any* NEON/VFP instructions
 *   outside a kernel_neon_begin()/kernel_neon_end() pair.
 */


#define RAID6_NEON_WRAPPER(_n)						\
	static void raid6_neon ## _n ## _gen_syndrome(int disks,        \
                                        size_t bytes, void **ptrs)      \
        {                                                               \
                void raid6_neon ## _n  ## _gen_syndrome_real(int,       \
                                                unsigned long, void**); \
                kernel_neon_begin();                                    \
                raid6_neon ## _n ## _gen_syndrome_real(disks,           \
                                        (unsigned long)bytes, ptrs);    \
                kernel_neon_end();                                      \
        }                                                               \
        static void raid6_neon ## _n ## _xor_syndrome(int disks,        \
                                        int start, int stop,            \
                                        size_t bytes, void **ptrs)      \
        {                                                               \
                void raid6_neon ## _n  ## _xor_syndrome_real(int,       \
                                int, int, unsigned long, void**);       \
                kernel_neon_begin();                                    \
                raid6_neon ## _n ## _xor_syndrome_real(disks,           \
                        start, stop, (unsigned long)bytes, ptrs);       \
                kernel_neon_end();                                      \
        }                                                               \
        struct raid6_calls const raid6_neonx ## _n = {                  \
                raid6_neon ## _n ## _gen_syndrome,                      \
                raid6_neon ## _n ## _xor_syndrome,                      \
                raid6_have_neon,                                        \
                "neonx" #_n,                                            \
                0                                                       \
        }


static int raid6_have_neon(void) { return cpu_has_neon(); }

Contributors

PersonTokensPropCommitsCommitProp
ard biesheuvelard biesheuvel12100.00%1100.00%
Total12100.00%1100.00%

RAID6_NEON_WRAPPER(1); RAID6_NEON_WRAPPER(2); RAID6_NEON_WRAPPER(4); RAID6_NEON_WRAPPER(8);

Overall Contributors

PersonTokensPropCommitsCommitProp
ard biesheuvelard biesheuvel68100.00%2100.00%
Total68100.00%2100.00%
Directory: lib/raid6