cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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dm-verity-fec.h (4350B)

      1/* SPDX-License-Identifier: GPL-2.0-or-later */
      2/*
      3 * Copyright (C) 2015 Google, Inc.
      4 *
      5 * Author: Sami Tolvanen <samitolvanen@google.com>
      6 */
      7
      8#ifndef DM_VERITY_FEC_H
      9#define DM_VERITY_FEC_H
     10
     11#include "dm-verity.h"
     12#include <linux/rslib.h>
     13
     14/* Reed-Solomon(M, N) parameters */
     15#define DM_VERITY_FEC_RSM		255
     16#define DM_VERITY_FEC_MAX_RSN		253
     17#define DM_VERITY_FEC_MIN_RSN		231	/* ~10% space overhead */
     18
     19/* buffers for deinterleaving and decoding */
     20#define DM_VERITY_FEC_BUF_PREALLOC	1	/* buffers to preallocate */
     21#define DM_VERITY_FEC_BUF_RS_BITS	4	/* 1 << RS blocks per buffer */
     22/* we need buffers for at most 1 << block size RS blocks */
     23#define DM_VERITY_FEC_BUF_MAX \
     24	(1 << (PAGE_SHIFT - DM_VERITY_FEC_BUF_RS_BITS))
     25
     26/* maximum recursion level for verity_fec_decode */
     27#define DM_VERITY_FEC_MAX_RECURSION	4
     28
     29#define DM_VERITY_OPT_FEC_DEV		"use_fec_from_device"
     30#define DM_VERITY_OPT_FEC_BLOCKS	"fec_blocks"
     31#define DM_VERITY_OPT_FEC_START		"fec_start"
     32#define DM_VERITY_OPT_FEC_ROOTS		"fec_roots"
     33
     34/* configuration */
     35struct dm_verity_fec {
     36	struct dm_dev *dev;	/* parity data device */
     37	struct dm_bufio_client *data_bufio;	/* for data dev access */
     38	struct dm_bufio_client *bufio;		/* for parity data access */
     39	size_t io_size;		/* IO size for roots */
     40	sector_t start;		/* parity data start in blocks */
     41	sector_t blocks;	/* number of blocks covered */
     42	sector_t rounds;	/* number of interleaving rounds */
     43	sector_t hash_blocks;	/* blocks covered after v->hash_start */
     44	unsigned char roots;	/* number of parity bytes, M-N of RS(M, N) */
     45	unsigned char rsn;	/* N of RS(M, N) */
     46	mempool_t rs_pool;	/* mempool for fio->rs */
     47	mempool_t prealloc_pool;	/* mempool for preallocated buffers */
     48	mempool_t extra_pool;	/* mempool for extra buffers */
     49	mempool_t output_pool;	/* mempool for output */
     50	struct kmem_cache *cache;	/* cache for buffers */
     51};
     52
     53/* per-bio data */
     54struct dm_verity_fec_io {
     55	struct rs_control *rs;	/* Reed-Solomon state */
     56	int erasures[DM_VERITY_FEC_MAX_RSN];	/* erasures for decode_rs8 */
     57	u8 *bufs[DM_VERITY_FEC_BUF_MAX];	/* bufs for deinterleaving */
     58	unsigned nbufs;		/* number of buffers allocated */
     59	u8 *output;		/* buffer for corrected output */
     60	size_t output_pos;
     61	unsigned level;		/* recursion level */
     62};
     63
     64#ifdef CONFIG_DM_VERITY_FEC
     65
     66/* each feature parameter requires a value */
     67#define DM_VERITY_OPTS_FEC	8
     68
     69extern bool verity_fec_is_enabled(struct dm_verity *v);
     70
     71extern int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io,
     72			     enum verity_block_type type, sector_t block,
     73			     u8 *dest, struct bvec_iter *iter);
     74
     75extern unsigned verity_fec_status_table(struct dm_verity *v, unsigned sz,
     76					char *result, unsigned maxlen);
     77
     78extern void verity_fec_finish_io(struct dm_verity_io *io);
     79extern void verity_fec_init_io(struct dm_verity_io *io);
     80
     81extern bool verity_is_fec_opt_arg(const char *arg_name);
     82extern int verity_fec_parse_opt_args(struct dm_arg_set *as,
     83				     struct dm_verity *v, unsigned *argc,
     84				     const char *arg_name);
     85
     86extern void verity_fec_dtr(struct dm_verity *v);
     87
     88extern int verity_fec_ctr_alloc(struct dm_verity *v);
     89extern int verity_fec_ctr(struct dm_verity *v);
     90
     91#else /* !CONFIG_DM_VERITY_FEC */
     92
     93#define DM_VERITY_OPTS_FEC	0
     94
     95static inline bool verity_fec_is_enabled(struct dm_verity *v)
     96{
     97	return false;
     98}
     99
    100static inline int verity_fec_decode(struct dm_verity *v,
    101				    struct dm_verity_io *io,
    102				    enum verity_block_type type,
    103				    sector_t block, u8 *dest,
    104				    struct bvec_iter *iter)
    105{
    106	return -EOPNOTSUPP;
    107}
    108
    109static inline unsigned verity_fec_status_table(struct dm_verity *v,
    110					       unsigned sz, char *result,
    111					       unsigned maxlen)
    112{
    113	return sz;
    114}
    115
    116static inline void verity_fec_finish_io(struct dm_verity_io *io)
    117{
    118}
    119
    120static inline void verity_fec_init_io(struct dm_verity_io *io)
    121{
    122}
    123
    124static inline bool verity_is_fec_opt_arg(const char *arg_name)
    125{
    126	return false;
    127}
    128
    129static inline int verity_fec_parse_opt_args(struct dm_arg_set *as,
    130					    struct dm_verity *v,
    131					    unsigned *argc,
    132					    const char *arg_name)
    133{
    134	return -EINVAL;
    135}
    136
    137static inline void verity_fec_dtr(struct dm_verity *v)
    138{
    139}
    140
    141static inline int verity_fec_ctr_alloc(struct dm_verity *v)
    142{
    143	return 0;
    144}
    145
    146static inline int verity_fec_ctr(struct dm_verity *v)
    147{
    148	return 0;
    149}
    150
    151#endif /* CONFIG_DM_VERITY_FEC */
    152
    153#endif /* DM_VERITY_FEC_H */