/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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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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#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, int num)
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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 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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