134 lines
3.7 KiB
C
134 lines
3.7 KiB
C
/*
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* Cryptographic scatter and gather helpers.
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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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* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
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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 <crypto/algapi.h>
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#include <linux/highmem.h>
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#include <linux/kernel.h>
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#include <linux/scatterlist.h>
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static inline void scatterwalk_crypto_chain(struct scatterlist *head,
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struct scatterlist *sg,
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int chain, int num)
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{
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if (chain) {
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head->length += sg->length;
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sg = sg_next(sg);
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}
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if (sg)
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sg_chain(head, num, sg);
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else
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sg_mark_end(head);
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}
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static inline unsigned long 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 !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
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(int)(walk_in->offset - walk_out->offset));
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}
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static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
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{
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unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
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unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
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return len_this_page > len ? len : len_this_page;
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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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unsigned int len_this_page = scatterwalk_pagelen(walk);
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return nbytes > len_this_page ? 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->offset += 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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static inline struct page *scatterwalk_page(struct scatter_walk *walk)
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{
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return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
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}
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static inline void scatterwalk_unmap(void *vaddr)
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{
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kunmap_atomic(vaddr);
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}
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static inline void scatterwalk_start(struct scatter_walk *walk,
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struct scatterlist *sg)
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{
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walk->sg = sg;
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walk->offset = sg->offset;
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}
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static inline void *scatterwalk_map(struct scatter_walk *walk)
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{
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return kmap_atomic(scatterwalk_page(walk)) +
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offset_in_page(walk->offset);
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}
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static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,
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unsigned int more)
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{
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if (out) {
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struct page *page;
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page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
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/* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
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* PageSlab cannot be optimised away per se due to
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* use of volatile pointer.
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*/
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if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
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flush_dcache_page(page);
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}
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if (more && walk->offset >= walk->sg->offset + walk->sg->length)
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scatterwalk_start(walk, sg_next(walk->sg));
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}
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static inline void scatterwalk_done(struct scatter_walk *walk, int out,
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int more)
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{
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if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
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!(walk->offset & (PAGE_SIZE - 1)))
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scatterwalk_pagedone(walk, out, more);
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}
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void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
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size_t nbytes, int out);
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void *scatterwalk_map(struct scatter_walk *walk);
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void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
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unsigned int start, unsigned int nbytes, int out);
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struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
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struct scatterlist *src,
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unsigned int len);
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#endif /* _CRYPTO_SCATTERWALK_H */
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