aboutsummaryrefslogtreecommitdiffstats
path: root/target/linux/generic/backport-5.4/080-wireguard-0005-crypto-arm64-chacha-depend-on-generic-chacha-library.patch
blob: eca55ed0376ed77f7e8a0afdd821e8323d8d591c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
From 527b7f4f3e244c58e07fdb7d850acb45821e1c52 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@kernel.org>
Date: Fri, 8 Nov 2019 13:22:11 +0100
Subject: [PATCH 005/124] crypto: arm64/chacha - depend on generic chacha
 library instead of crypto driver

commit c77da4867cbb7841177275dbb250f5c09679fae4 upstream.

Depend on the generic ChaCha library routines instead of pulling in the
generic ChaCha skcipher driver, which is more than we need, and makes
managing the dependencies between the generic library, generic driver,
accelerated library and driver more complicated.

While at it, drop the logic to prefer the scalar code on short inputs.
Turning the NEON on and off is cheap these days, and one major use case
for ChaCha20 is ChaCha20-Poly1305, which is guaranteed to hit the scalar
path upon every invocation  (when doing the Poly1305 nonce generation)

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 arch/arm64/crypto/Kconfig            |  2 +-
 arch/arm64/crypto/chacha-neon-glue.c | 40 +++++++++++++++-------------
 2 files changed, 23 insertions(+), 19 deletions(-)

--- a/arch/arm64/crypto/Kconfig
+++ b/arch/arm64/crypto/Kconfig
@@ -103,7 +103,7 @@ config CRYPTO_CHACHA20_NEON
 	tristate "ChaCha20, XChaCha20, and XChaCha12 stream ciphers using NEON instructions"
 	depends on KERNEL_MODE_NEON
 	select CRYPTO_BLKCIPHER
-	select CRYPTO_CHACHA20
+	select CRYPTO_LIB_CHACHA_GENERIC
 
 config CRYPTO_NHPOLY1305_NEON
 	tristate "NHPoly1305 hash function using NEON instructions (for Adiantum)"
--- a/arch/arm64/crypto/chacha-neon-glue.c
+++ b/arch/arm64/crypto/chacha-neon-glue.c
@@ -68,7 +68,7 @@ static int chacha_neon_stream_xor(struct
 
 	err = skcipher_walk_virt(&walk, req, false);
 
-	crypto_chacha_init(state, ctx, iv);
+	chacha_init_generic(state, ctx->key, iv);
 
 	while (walk.nbytes > 0) {
 		unsigned int nbytes = walk.nbytes;
@@ -76,10 +76,16 @@ static int chacha_neon_stream_xor(struct
 		if (nbytes < walk.total)
 			nbytes = rounddown(nbytes, walk.stride);
 
-		kernel_neon_begin();
-		chacha_doneon(state, walk.dst.virt.addr, walk.src.virt.addr,
-			      nbytes, ctx->nrounds);
-		kernel_neon_end();
+		if (!crypto_simd_usable()) {
+			chacha_crypt_generic(state, walk.dst.virt.addr,
+					     walk.src.virt.addr, nbytes,
+					     ctx->nrounds);
+		} else {
+			kernel_neon_begin();
+			chacha_doneon(state, walk.dst.virt.addr,
+				      walk.src.virt.addr, nbytes, ctx->nrounds);
+			kernel_neon_end();
+		}
 		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
 	}
 
@@ -91,9 +97,6 @@ static int chacha_neon(struct skcipher_r
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
 
-	if (req->cryptlen <= CHACHA_BLOCK_SIZE || !crypto_simd_usable())
-		return crypto_chacha_crypt(req);
-
 	return chacha_neon_stream_xor(req, ctx, req->iv);
 }
 
@@ -105,14 +108,15 @@ static int xchacha_neon(struct skcipher_
 	u32 state[16];
 	u8 real_iv[16];
 
-	if (req->cryptlen <= CHACHA_BLOCK_SIZE || !crypto_simd_usable())
-		return crypto_xchacha_crypt(req);
-
-	crypto_chacha_init(state, ctx, req->iv);
+	chacha_init_generic(state, ctx->key, req->iv);
 
-	kernel_neon_begin();
-	hchacha_block_neon(state, subctx.key, ctx->nrounds);
-	kernel_neon_end();
+	if (crypto_simd_usable()) {
+		kernel_neon_begin();
+		hchacha_block_neon(state, subctx.key, ctx->nrounds);
+		kernel_neon_end();
+	} else {
+		hchacha_block_generic(state, subctx.key, ctx->nrounds);
+	}
 	subctx.nrounds = ctx->nrounds;
 
 	memcpy(&real_iv[0], req->iv + 24, 8);
@@ -134,7 +138,7 @@ static struct skcipher_alg algs[] = {
 		.ivsize			= CHACHA_IV_SIZE,
 		.chunksize		= CHACHA_BLOCK_SIZE,
 		.walksize		= 5 * CHACHA_BLOCK_SIZE,
-		.setkey			= crypto_chacha20_setkey,
+		.setkey			= chacha20_setkey,
 		.encrypt		= chacha_neon,
 		.decrypt		= chacha_neon,
 	}, {
@@ -150,7 +154,7 @@ static struct skcipher_alg algs[] = {
 		.ivsize			= XCHACHA_IV_SIZE,
 		.chunksize		= CHACHA_BLOCK_SIZE,
 		.walksize		= 5 * CHACHA_BLOCK_SIZE,
-		.setkey			= crypto_chacha20_setkey,
+		.setkey			= chacha20_setkey,
 		.encrypt		= xchacha_neon,
 		.decrypt		= xchacha_neon,
 	}, {
@@ -166,7 +170,7 @@ static struct skcipher_alg algs[] = {
 		.ivsize			= XCHACHA_IV_SIZE,
 		.chunksize		= CHACHA_BLOCK_SIZE,
 		.walksize		= 5 * CHACHA_BLOCK_SIZE,
-		.setkey			= crypto_chacha12_setkey,
+		.setkey			= chacha12_setkey,
 		.encrypt		= xchacha_neon,
 		.decrypt		= xchacha_neon,
 	}