diff options
author | Mandeep Singh Baines <msb@chromium.org> | 2011-08-05 21:46:27 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-08-06 14:26:52 -0400 |
commit | 1eb19a12bd2214cdcad5273d472b062a4ba97fa1 (patch) | |
tree | a88b76f31a4ea5e3631581be249759fcf4b05a08 /lib | |
parent | de96355c111679dd6e2c5c73e25e814c72510c58 (diff) |
lib/sha1: use the git implementation of SHA-1
For ChromiumOS, we use SHA-1 to verify the integrity of the root
filesystem. The speed of the kernel sha-1 implementation has a major
impact on our boot performance.
To improve boot performance, we investigated using the heavily optimized
sha-1 implementation used in git. With the git sha-1 implementation, we
see a 11.7% improvement in boot time.
10 reboots, remove slowest/fastest.
Before:
Mean: 6.58 seconds Stdev: 0.14
After (with git sha-1, this patch):
Mean: 5.89 seconds Stdev: 0.07
The other cool thing about the git SHA-1 implementation is that it only
needs 64 bytes of stack for the workspace while the original kernel
implementation needed 320 bytes.
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Cc: Nicolas Pitre <nico@cam.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David S. Miller <davem@davemloft.net>
Cc: linux-crypto@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/sha1.c | 212 |
1 files changed, 158 insertions, 54 deletions
diff --git a/lib/sha1.c b/lib/sha1.c index 4c45fd50e913..f33271dd00cb 100644 --- a/lib/sha1.c +++ b/lib/sha1.c | |||
@@ -1,31 +1,72 @@ | |||
1 | /* | 1 | /* |
2 | * SHA transform algorithm, originally taken from code written by | 2 | * SHA1 routine optimized to do word accesses rather than byte accesses, |
3 | * Peter Gutmann, and placed in the public domain. | 3 | * and to avoid unnecessary copies into the context array. |
4 | * | ||
5 | * This was based on the git SHA1 implementation. | ||
4 | */ | 6 | */ |
5 | 7 | ||
6 | #include <linux/kernel.h> | 8 | #include <linux/kernel.h> |
7 | #include <linux/module.h> | 9 | #include <linux/module.h> |
8 | #include <linux/cryptohash.h> | 10 | #include <linux/bitops.h> |
11 | #include <asm/unaligned.h> | ||
9 | 12 | ||
10 | /* The SHA f()-functions. */ | 13 | /* |
14 | * If you have 32 registers or more, the compiler can (and should) | ||
15 | * try to change the array[] accesses into registers. However, on | ||
16 | * machines with less than ~25 registers, that won't really work, | ||
17 | * and at least gcc will make an unholy mess of it. | ||
18 | * | ||
19 | * So to avoid that mess which just slows things down, we force | ||
20 | * the stores to memory to actually happen (we might be better off | ||
21 | * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as | ||
22 | * suggested by Artur Skawina - that will also make gcc unable to | ||
23 | * try to do the silly "optimize away loads" part because it won't | ||
24 | * see what the value will be). | ||
25 | * | ||
26 | * Ben Herrenschmidt reports that on PPC, the C version comes close | ||
27 | * to the optimized asm with this (ie on PPC you don't want that | ||
28 | * 'volatile', since there are lots of registers). | ||
29 | * | ||
30 | * On ARM we get the best code generation by forcing a full memory barrier | ||
31 | * between each SHA_ROUND, otherwise gcc happily get wild with spilling and | ||
32 | * the stack frame size simply explode and performance goes down the drain. | ||
33 | */ | ||
11 | 34 | ||
12 | #define f1(x,y,z) (z ^ (x & (y ^ z))) /* x ? y : z */ | 35 | #ifdef CONFIG_X86 |
13 | #define f2(x,y,z) (x ^ y ^ z) /* XOR */ | 36 | #define setW(x, val) (*(volatile __u32 *)&W(x) = (val)) |
14 | #define f3(x,y,z) ((x & y) + (z & (x ^ y))) /* majority */ | 37 | #elif defined(CONFIG_ARM) |
38 | #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0) | ||
39 | #else | ||
40 | #define setW(x, val) (W(x) = (val)) | ||
41 | #endif | ||
15 | 42 | ||
16 | /* The SHA Mysterious Constants */ | 43 | /* This "rolls" over the 512-bit array */ |
44 | #define W(x) (array[(x)&15]) | ||
17 | 45 | ||
18 | #define K1 0x5A827999L /* Rounds 0-19: sqrt(2) * 2^30 */ | 46 | /* |
19 | #define K2 0x6ED9EBA1L /* Rounds 20-39: sqrt(3) * 2^30 */ | 47 | * Where do we get the source from? The first 16 iterations get it from |
20 | #define K3 0x8F1BBCDCL /* Rounds 40-59: sqrt(5) * 2^30 */ | 48 | * the input data, the next mix it from the 512-bit array. |
21 | #define K4 0xCA62C1D6L /* Rounds 60-79: sqrt(10) * 2^30 */ | 49 | */ |
50 | #define SHA_SRC(t) get_unaligned_be32((__u32 *)data + t) | ||
51 | #define SHA_MIX(t) rol32(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1) | ||
52 | |||
53 | #define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \ | ||
54 | __u32 TEMP = input(t); setW(t, TEMP); \ | ||
55 | E += TEMP + rol32(A,5) + (fn) + (constant); \ | ||
56 | B = ror32(B, 2); } while (0) | ||
57 | |||
58 | #define T_0_15(t, A, B, C, D, E) SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E ) | ||
59 | #define T_16_19(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E ) | ||
60 | #define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E ) | ||
61 | #define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc, A, B, C, D, E ) | ||
62 | #define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6, A, B, C, D, E ) | ||
22 | 63 | ||
23 | /** | 64 | /** |
24 | * sha_transform - single block SHA1 transform | 65 | * sha_transform - single block SHA1 transform |
25 | * | 66 | * |
26 | * @digest: 160 bit digest to update | 67 | * @digest: 160 bit digest to update |
27 | * @data: 512 bits of data to hash | 68 | * @data: 512 bits of data to hash |
28 | * @W: 80 words of workspace (see note) | 69 | * @array: 16 words of workspace (see note) |
29 | * | 70 | * |
30 | * This function generates a SHA1 digest for a single 512-bit block. | 71 | * This function generates a SHA1 digest for a single 512-bit block. |
31 | * Be warned, it does not handle padding and message digest, do not | 72 | * Be warned, it does not handle padding and message digest, do not |
@@ -36,47 +77,111 @@ | |||
36 | * to clear the workspace. This is left to the caller to avoid | 77 | * to clear the workspace. This is left to the caller to avoid |
37 | * unnecessary clears between chained hashing operations. | 78 | * unnecessary clears between chained hashing operations. |
38 | */ | 79 | */ |
39 | void sha_transform(__u32 *digest, const char *in, __u32 *W) | 80 | void sha_transform(__u32 *digest, const char *data, __u32 *array) |
40 | { | 81 | { |
41 | __u32 a, b, c, d, e, t, i; | 82 | __u32 A, B, C, D, E; |
42 | 83 | ||
43 | for (i = 0; i < 16; i++) | 84 | A = digest[0]; |
44 | W[i] = be32_to_cpu(((const __be32 *)in)[i]); | 85 | B = digest[1]; |
45 | 86 | C = digest[2]; | |
46 | for (i = 0; i < 64; i++) | 87 | D = digest[3]; |
47 | W[i+16] = rol32(W[i+13] ^ W[i+8] ^ W[i+2] ^ W[i], 1); | 88 | E = digest[4]; |
48 | 89 | ||
49 | a = digest[0]; | 90 | /* Round 1 - iterations 0-16 take their input from 'data' */ |
50 | b = digest[1]; | 91 | T_0_15( 0, A, B, C, D, E); |
51 | c = digest[2]; | 92 | T_0_15( 1, E, A, B, C, D); |
52 | d = digest[3]; | 93 | T_0_15( 2, D, E, A, B, C); |
53 | e = digest[4]; | 94 | T_0_15( 3, C, D, E, A, B); |
54 | 95 | T_0_15( 4, B, C, D, E, A); | |
55 | for (i = 0; i < 20; i++) { | 96 | T_0_15( 5, A, B, C, D, E); |
56 | t = f1(b, c, d) + K1 + rol32(a, 5) + e + W[i]; | 97 | T_0_15( 6, E, A, B, C, D); |
57 | e = d; d = c; c = rol32(b, 30); b = a; a = t; | 98 | T_0_15( 7, D, E, A, B, C); |
58 | } | 99 | T_0_15( 8, C, D, E, A, B); |
59 | 100 | T_0_15( 9, B, C, D, E, A); | |
60 | for (; i < 40; i ++) { | 101 | T_0_15(10, A, B, C, D, E); |
61 | t = f2(b, c, d) + K2 + rol32(a, 5) + e + W[i]; | 102 | T_0_15(11, E, A, B, C, D); |
62 | e = d; d = c; c = rol32(b, 30); b = a; a = t; | 103 | T_0_15(12, D, E, A, B, C); |
63 | } | 104 | T_0_15(13, C, D, E, A, B); |
64 | 105 | T_0_15(14, B, C, D, E, A); | |
65 | for (; i < 60; i ++) { | 106 | T_0_15(15, A, B, C, D, E); |
66 | t = f3(b, c, d) + K3 + rol32(a, 5) + e + W[i]; | 107 | |
67 | e = d; d = c; c = rol32(b, 30); b = a; a = t; | 108 | /* Round 1 - tail. Input from 512-bit mixing array */ |
68 | } | 109 | T_16_19(16, E, A, B, C, D); |
69 | 110 | T_16_19(17, D, E, A, B, C); | |
70 | for (; i < 80; i ++) { | 111 | T_16_19(18, C, D, E, A, B); |
71 | t = f2(b, c, d) + K4 + rol32(a, 5) + e + W[i]; | 112 | T_16_19(19, B, C, D, E, A); |
72 | e = d; d = c; c = rol32(b, 30); b = a; a = t; | 113 | |
73 | } | 114 | /* Round 2 */ |
74 | 115 | T_20_39(20, A, B, C, D, E); | |
75 | digest[0] += a; | 116 | T_20_39(21, E, A, B, C, D); |
76 | digest[1] += b; | 117 | T_20_39(22, D, E, A, B, C); |
77 | digest[2] += c; | 118 | T_20_39(23, C, D, E, A, B); |
78 | digest[3] += d; | 119 | T_20_39(24, B, C, D, E, A); |
79 | digest[4] += e; | 120 | T_20_39(25, A, B, C, D, E); |
121 | T_20_39(26, E, A, B, C, D); | ||
122 | T_20_39(27, D, E, A, B, C); | ||
123 | T_20_39(28, C, D, E, A, B); | ||
124 | T_20_39(29, B, C, D, E, A); | ||
125 | T_20_39(30, A, B, C, D, E); | ||
126 | T_20_39(31, E, A, B, C, D); | ||
127 | T_20_39(32, D, E, A, B, C); | ||
128 | T_20_39(33, C, D, E, A, B); | ||
129 | T_20_39(34, B, C, D, E, A); | ||
130 | T_20_39(35, A, B, C, D, E); | ||
131 | T_20_39(36, E, A, B, C, D); | ||
132 | T_20_39(37, D, E, A, B, C); | ||
133 | T_20_39(38, C, D, E, A, B); | ||
134 | T_20_39(39, B, C, D, E, A); | ||
135 | |||
136 | /* Round 3 */ | ||
137 | T_40_59(40, A, B, C, D, E); | ||
138 | T_40_59(41, E, A, B, C, D); | ||
139 | T_40_59(42, D, E, A, B, C); | ||
140 | T_40_59(43, C, D, E, A, B); | ||
141 | T_40_59(44, B, C, D, E, A); | ||
142 | T_40_59(45, A, B, C, D, E); | ||
143 | T_40_59(46, E, A, B, C, D); | ||
144 | T_40_59(47, D, E, A, B, C); | ||
145 | T_40_59(48, C, D, E, A, B); | ||
146 | T_40_59(49, B, C, D, E, A); | ||
147 | T_40_59(50, A, B, C, D, E); | ||
148 | T_40_59(51, E, A, B, C, D); | ||
149 | T_40_59(52, D, E, A, B, C); | ||
150 | T_40_59(53, C, D, E, A, B); | ||
151 | T_40_59(54, B, C, D, E, A); | ||
152 | T_40_59(55, A, B, C, D, E); | ||
153 | T_40_59(56, E, A, B, C, D); | ||
154 | T_40_59(57, D, E, A, B, C); | ||
155 | T_40_59(58, C, D, E, A, B); | ||
156 | T_40_59(59, B, C, D, E, A); | ||
157 | |||
158 | /* Round 4 */ | ||
159 | T_60_79(60, A, B, C, D, E); | ||
160 | T_60_79(61, E, A, B, C, D); | ||
161 | T_60_79(62, D, E, A, B, C); | ||
162 | T_60_79(63, C, D, E, A, B); | ||
163 | T_60_79(64, B, C, D, E, A); | ||
164 | T_60_79(65, A, B, C, D, E); | ||
165 | T_60_79(66, E, A, B, C, D); | ||
166 | T_60_79(67, D, E, A, B, C); | ||
167 | T_60_79(68, C, D, E, A, B); | ||
168 | T_60_79(69, B, C, D, E, A); | ||
169 | T_60_79(70, A, B, C, D, E); | ||
170 | T_60_79(71, E, A, B, C, D); | ||
171 | T_60_79(72, D, E, A, B, C); | ||
172 | T_60_79(73, C, D, E, A, B); | ||
173 | T_60_79(74, B, C, D, E, A); | ||
174 | T_60_79(75, A, B, C, D, E); | ||
175 | T_60_79(76, E, A, B, C, D); | ||
176 | T_60_79(77, D, E, A, B, C); | ||
177 | T_60_79(78, C, D, E, A, B); | ||
178 | T_60_79(79, B, C, D, E, A); | ||
179 | |||
180 | digest[0] += A; | ||
181 | digest[1] += B; | ||
182 | digest[2] += C; | ||
183 | digest[3] += D; | ||
184 | digest[4] += E; | ||
80 | } | 185 | } |
81 | EXPORT_SYMBOL(sha_transform); | 186 | EXPORT_SYMBOL(sha_transform); |
82 | 187 | ||
@@ -92,4 +197,3 @@ void sha_init(__u32 *buf) | |||
92 | buf[3] = 0x10325476; | 197 | buf[3] = 0x10325476; |
93 | buf[4] = 0xc3d2e1f0; | 198 | buf[4] = 0xc3d2e1f0; |
94 | } | 199 | } |
95 | |||