Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0-or-later */
       2             : /*
       3             :  * Cryptographic scatter and gather helpers.
       4             :  *
       5             :  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
       6             :  * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
       7             :  * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
       8             :  * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
       9             :  */
      10             : 
      11             : #ifndef _CRYPTO_SCATTERWALK_H
      12             : #define _CRYPTO_SCATTERWALK_H
      13             : 
      14             : #include <crypto/algapi.h>
      15             : #include <linux/highmem.h>
      16             : #include <linux/kernel.h>
      17             : #include <linux/scatterlist.h>
      18             : 
      19           0 : static inline void scatterwalk_crypto_chain(struct scatterlist *head,
      20             :                                             struct scatterlist *sg, int num)
      21             : {
      22           0 :         if (sg)
      23           0 :                 sg_chain(head, num, sg);
      24             :         else
      25           0 :                 sg_mark_end(head);
      26           0 : }
      27             : 
      28           0 : static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
      29             : {
      30           0 :         unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
      31           0 :         unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
      32           0 :         return len_this_page > len ? len : len_this_page;
      33             : }
      34             : 
      35           0 : static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
      36             :                                              unsigned int nbytes)
      37             : {
      38           0 :         unsigned int len_this_page = scatterwalk_pagelen(walk);
      39           0 :         return nbytes > len_this_page ? len_this_page : nbytes;
      40             : }
      41             : 
      42           0 : static inline void scatterwalk_advance(struct scatter_walk *walk,
      43             :                                        unsigned int nbytes)
      44             : {
      45           0 :         walk->offset += nbytes;
      46             : }
      47             : 
      48             : static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
      49             :                                                unsigned int alignmask)
      50             : {
      51             :         return !(walk->offset & alignmask);
      52             : }
      53             : 
      54           0 : static inline struct page *scatterwalk_page(struct scatter_walk *walk)
      55             : {
      56           0 :         return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
      57             : }
      58             : 
      59           0 : static inline void scatterwalk_unmap(void *vaddr)
      60             : {
      61           0 :         kunmap_atomic(vaddr);
      62           0 : }
      63             : 
      64           0 : static inline void scatterwalk_start(struct scatter_walk *walk,
      65             :                                      struct scatterlist *sg)
      66             : {
      67           0 :         walk->sg = sg;
      68           0 :         walk->offset = sg->offset;
      69           0 : }
      70             : 
      71           0 : static inline void *scatterwalk_map(struct scatter_walk *walk)
      72             : {
      73           0 :         return kmap_atomic(scatterwalk_page(walk)) +
      74           0 :                offset_in_page(walk->offset);
      75             : }
      76             : 
      77           0 : static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,
      78             :                                         unsigned int more)
      79             : {
      80           0 :         if (out) {
      81             :                 struct page *page;
      82             : 
      83             :                 page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
      84             :                 /* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
      85             :                  * PageSlab cannot be optimised away per se due to
      86             :                  * use of volatile pointer.
      87             :                  */
      88             :                 if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
      89             :                         flush_dcache_page(page);
      90             :         }
      91             : 
      92           0 :         if (more && walk->offset >= walk->sg->offset + walk->sg->length)
      93           0 :                 scatterwalk_start(walk, sg_next(walk->sg));
      94           0 : }
      95             : 
      96           0 : static inline void scatterwalk_done(struct scatter_walk *walk, int out,
      97             :                                     int more)
      98             : {
      99           0 :         if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
     100             :             !(walk->offset & (PAGE_SIZE - 1)))
     101           0 :                 scatterwalk_pagedone(walk, out, more);
     102           0 : }
     103             : 
     104             : void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
     105             :                             size_t nbytes, int out);
     106             : void *scatterwalk_map(struct scatter_walk *walk);
     107             : 
     108             : void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
     109             :                               unsigned int start, unsigned int nbytes, int out);
     110             : 
     111             : struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
     112             :                                      struct scatterlist *src,
     113             :                                      unsigned int len);
     114             : 
     115             : #endif  /* _CRYPTO_SCATTERWALK_H */