glue_helper.h

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/*
 * Shared glue code for 128bit block ciphers
 */

#ifndef _CRYPTO_GLUE_HELPER_H
#define _CRYPTO_GLUE_HELPER_H

#include <linux/kernel.h>
#include <linux/crypto.h>
#include <asm/i387.h>
#include <crypto/b128ops.h>

typedef void (*common_glue_func_t)(void *ctx, u8 *dst, const u8 *src);
typedef void (*common_glue_cbc_func_t)(void *ctx, u128 *dst, const u128 *src);
typedef void (*common_glue_ctr_func_t)(void *ctx, u128 *dst, const u128 *src,
                       u128 *iv);

#define GLUE_FUNC_CAST(fn) ((common_glue_func_t)(fn))
#define GLUE_CBC_FUNC_CAST(fn) ((common_glue_cbc_func_t)(fn))
#define GLUE_CTR_FUNC_CAST(fn) ((common_glue_ctr_func_t)(fn))

struct common_glue_func_entry {
    unsigned int num_blocks; /* number of blocks that @fn will process */
    union {
        common_glue_func_t ecb;
        common_glue_cbc_func_t cbc;
        common_glue_ctr_func_t ctr;
    } fn_u;
};

struct common_glue_ctx {
    unsigned int num_funcs;
    int fpu_blocks_limit; /* -1 means fpu not needed at all */

    /*
     * First funcs entry must have largest num_blocks and last funcs entry
     * must have num_blocks == 1!
     */
    struct common_glue_func_entry funcs[];
};

static inline bool glue_fpu_begin(unsigned int bsize, int fpu_blocks_limit,
                  struct blkcipher_desc *desc,
                  bool fpu_enabled, unsigned int nbytes)
{
    if (likely(fpu_blocks_limit < 0))
        return false;

    if (fpu_enabled)
        return true;

    /*
     * Vector-registers are only used when chunk to be processed is large
     * enough, so do not enable FPU until it is necessary.
     */
    if (nbytes < bsize * (unsigned int)fpu_blocks_limit)
        return false;

    if (desc) {
        /* prevent sleeping if FPU is in use */
        desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
    }

    kernel_fpu_begin();
    return true;
}

static inline void glue_fpu_end(bool fpu_enabled)
{
    if (fpu_enabled)
        kernel_fpu_end();
}

static inline void u128_to_be128(be128 *dst, const u128 *src)
{
    dst->a = cpu_to_be64(src->a);
    dst->b = cpu_to_be64(src->b);
}

static inline void be128_to_u128(u128 *dst, const be128 *src)
{
    dst->a = be64_to_cpu(src->a);
    dst->b = be64_to_cpu(src->b);
}

static inline void u128_inc(u128 *i)
{
    i->b++;
    if (!i->b)
        i->a++;
}

extern int glue_ecb_crypt_128bit(const struct common_glue_ctx *gctx,
                 struct blkcipher_desc *desc,
                 struct scatterlist *dst,
                 struct scatterlist *src, unsigned int nbytes);

extern int glue_cbc_encrypt_128bit(const common_glue_func_t fn,
                   struct blkcipher_desc *desc,
                   struct scatterlist *dst,
                   struct scatterlist *src,
                   unsigned int nbytes);

extern int glue_cbc_decrypt_128bit(const struct common_glue_ctx *gctx,
                   struct blkcipher_desc *desc,
                   struct scatterlist *dst,
                   struct scatterlist *src,
                   unsigned int nbytes);

extern int glue_ctr_crypt_128bit(const struct common_glue_ctx *gctx,
                 struct blkcipher_desc *desc,
                 struct scatterlist *dst,
                 struct scatterlist *src, unsigned int nbytes);

#endif /* _CRYPTO_GLUE_HELPER_H */