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https://github.com/torvalds/linux
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9547737799
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>
70 lines
2 KiB
C
70 lines
2 KiB
C
/*
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* Cryptographic API.
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*
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* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
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* Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
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* Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#ifndef _CRYPTO_SCATTERWALK_H
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#define _CRYPTO_SCATTERWALK_H
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#include <linux/mm.h>
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#include <asm/scatterlist.h>
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struct scatter_walk {
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struct scatterlist *sg;
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struct page *page;
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void *data;
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unsigned int len_this_page;
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unsigned int len_this_segment;
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unsigned int offset;
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};
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/* Define sg_next is an inline routine now in case we want to change
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scatterlist to a linked list later. */
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static inline struct scatterlist *sg_next(struct scatterlist *sg)
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{
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return sg + 1;
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}
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static inline int scatterwalk_samebuf(struct scatter_walk *walk_in,
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struct scatter_walk *walk_out)
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{
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return walk_in->page == walk_out->page &&
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walk_in->offset == walk_out->offset;
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}
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static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
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unsigned int nbytes)
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{
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return nbytes > walk->len_this_page ? walk->len_this_page : nbytes;
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}
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static inline void scatterwalk_advance(struct scatter_walk *walk,
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unsigned int nbytes)
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{
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walk->data += nbytes;
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walk->offset += nbytes;
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walk->len_this_page -= nbytes;
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walk->len_this_segment -= nbytes;
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}
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static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
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unsigned int alignmask)
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{
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return !(walk->offset & alignmask);
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}
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void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
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int scatterwalk_copychunks(void *buf, struct scatter_walk *walk, size_t nbytes, int out);
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void scatterwalk_map(struct scatter_walk *walk, int out);
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void scatterwalk_done(struct scatter_walk *walk, int out, int more);
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#endif /* _CRYPTO_SCATTERWALK_H */
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