1 /* SPDX-License-Identifier: GPL-2.0 */
2 
3 #ifndef _CRYPTO_ECB_CBC_HELPER_H
4 #define _CRYPTO_ECB_CBC_HELPER_H
5 
6 #include <crypto/internal/skcipher.h>
7 #include <asm/fpu/api.h>
8 
9 /*
10  * Mode helpers to instantiate parameterized skcipher ECB/CBC modes without
11  * having to rely on indirect calls and retpolines.
12  */
13 
14 #define ECB_WALK_START(req, bsize, fpu_blocks) do {			\
15 	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));	\
16 	const int __bsize = (bsize);					\
17 	struct skcipher_walk walk;					\
18 	int err = skcipher_walk_virt(&walk, (req), false);		\
19 	while (walk.nbytes > 0) {					\
20 		unsigned int nbytes = walk.nbytes;			\
21 		bool do_fpu = (fpu_blocks) != -1 &&			\
22 			      nbytes >= (fpu_blocks) * __bsize;		\
23 		const u8 *src = walk.src.virt.addr;			\
24 		u8 *dst = walk.dst.virt.addr;				\
25 		u8 __maybe_unused buf[(bsize)];				\
26 		if (do_fpu) kernel_fpu_begin()
27 
28 #define CBC_WALK_START(req, bsize, fpu_blocks)				\
29 	ECB_WALK_START(req, bsize, fpu_blocks)
30 
31 #define ECB_WALK_ADVANCE(blocks) do {					\
32 	dst += (blocks) * __bsize;					\
33 	src += (blocks) * __bsize;					\
34 	nbytes -= (blocks) * __bsize;					\
35 } while (0)
36 
37 #define ECB_BLOCK(blocks, func) do {					\
38 	while (nbytes >= (blocks) * __bsize) {				\
39 		(func)(ctx, dst, src);					\
40 		ECB_WALK_ADVANCE(blocks);				\
41 	}								\
42 } while (0)
43 
44 #define CBC_ENC_BLOCK(func) do {					\
45 	const u8 *__iv = walk.iv;					\
46 	while (nbytes >= __bsize) {					\
47 		crypto_xor_cpy(dst, src, __iv, __bsize);		\
48 		(func)(ctx, dst, dst);					\
49 		__iv = dst;						\
50 		ECB_WALK_ADVANCE(1);					\
51 	}								\
52 	memcpy(walk.iv, __iv, __bsize);					\
53 } while (0)
54 
55 #define CBC_DEC_BLOCK(blocks, func) do {				\
56 	while (nbytes >= (blocks) * __bsize) {				\
57 		const u8 *__iv = src + ((blocks) - 1) * __bsize;	\
58 		if (dst == src)						\
59 			__iv = memcpy(buf, __iv, __bsize);		\
60 		(func)(ctx, dst, src);					\
61 		crypto_xor(dst, walk.iv, __bsize);			\
62 		memcpy(walk.iv, __iv, __bsize);				\
63 		ECB_WALK_ADVANCE(blocks);				\
64 	}								\
65 } while (0)
66 
67 #define ECB_WALK_END()							\
68 		if (do_fpu) kernel_fpu_end();				\
69 		err = skcipher_walk_done(&walk, nbytes);		\
70 	}								\
71 	return err;							\
72 } while (0)
73 
74 #define CBC_WALK_END() ECB_WALK_END()
75 
76 #endif
77