Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
lib/crypto: aes: Drop 'volatile' from aes_sbox and aes_inv_sbox
The volatile keyword is no longer necessary or useful on aes_sbox and
aes_inv_sbox, since the table prefetching is now done using a helper
function that casts to volatile itself and also includes an optimization
barrier. Since it prevents some compiler optimizations, remove it.
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20260112192035.10427-36-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
+3
-7
+3
-7
lib/crypto/aes.c
+3
-7
lib/crypto/aes.c
···
11
11
#include <linux/module.h>
12
12
#include <linux/unaligned.h>
13
13
14
-
/*
15
-
* Emit the sbox as volatile const to prevent the compiler from doing
16
-
* constant folding on sbox references involving fixed indexes.
17
-
*/
18
-
static volatile const u8 ____cacheline_aligned aes_sbox[] = {
14
+
static const u8 ____cacheline_aligned aes_sbox[] = {
19
15
0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5,
20
16
0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
21
17
0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
···
46
50
0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16,
47
51
};
48
52
49
-
static volatile const u8 ____cacheline_aligned aes_inv_sbox[] = {
53
+
static const u8 ____cacheline_aligned aes_inv_sbox[] = {
50
54
0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38,
51
55
0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
52
56
0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87,
···
426
430
w[3] = w3;
427
431
} while (--n);
428
432
429
-
aes_prefetch((const void *)aes_inv_sbox, sizeof(aes_inv_sbox));
433
+
aes_prefetch(aes_inv_sbox, sizeof(aes_inv_sbox));
430
434
put_unaligned_le32(declast_quarterround(w, 0, *rkp++), &out[0]);
431
435
put_unaligned_le32(declast_quarterround(w, 1, *rkp++), &out[4]);
432
436
put_unaligned_le32(declast_quarterround(w, 2, *rkp++), &out[8]);