linux-IllusionX/crypto/scatterwalk.h
Herbert Xu 9547737799 [CRYPTO] Add alignmask for low-level cipher implementations
The VIA Padlock device requires the input and output buffers to
be aligned on 16-byte boundaries.  This patch adds the alignmask
attribute for low-level cipher implementations to indicate their
alignment requirements.

The mid-level crypt() function will copy the input/output buffers
if they are not aligned correctly before they are passed to the
low-level implementation.

Strictly speaking, some of the software implementations require
the buffers to be aligned on 4-byte boundaries as they do 32-bit
loads.  However, it is not clear whether it is better to copy
the buffers or pay the penalty for unaligned loads/stores.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-06 13:52:09 -07:00

69 lines
2 KiB
C

/*
* Cryptographic API.
*
* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
* Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
* Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#ifndef _CRYPTO_SCATTERWALK_H
#define _CRYPTO_SCATTERWALK_H
#include <linux/mm.h>
#include <asm/scatterlist.h>
struct scatter_walk {
struct scatterlist *sg;
struct page *page;
void *data;
unsigned int len_this_page;
unsigned int len_this_segment;
unsigned int offset;
};
/* Define sg_next is an inline routine now in case we want to change
scatterlist to a linked list later. */
static inline struct scatterlist *sg_next(struct scatterlist *sg)
{
return sg + 1;
}
static inline int scatterwalk_samebuf(struct scatter_walk *walk_in,
struct scatter_walk *walk_out)
{
return walk_in->page == walk_out->page &&
walk_in->offset == walk_out->offset;
}
static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
unsigned int nbytes)
{
return nbytes > walk->len_this_page ? walk->len_this_page : nbytes;
}
static inline void scatterwalk_advance(struct scatter_walk *walk,
unsigned int nbytes)
{
walk->data += nbytes;
walk->offset += nbytes;
walk->len_this_page -= nbytes;
walk->len_this_segment -= nbytes;
}
static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
unsigned int alignmask)
{
return !(walk->offset & alignmask);
}
void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
int scatterwalk_copychunks(void *buf, struct scatter_walk *walk, size_t nbytes, int out);
void scatterwalk_map(struct scatter_walk *walk, int out);
void scatterwalk_done(struct scatter_walk *walk, int out, int more);
#endif /* _CRYPTO_SCATTERWALK_H */