From fbfeca74043777b48add294089cd4c4f68ed3377 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 12 Jan 2026 11:20:33 -0800 Subject: [PATCH] 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 Link: https://lore.kernel.org/r/20260112192035.10427-36-ebiggers@kernel.org Signed-off-by: Eric Biggers --- lib/crypto/aes.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/lib/crypto/aes.c b/lib/crypto/aes.c index b7ab2d0c4e593..b73e19f1bb950 100644 --- a/lib/crypto/aes.c +++ b/lib/crypto/aes.c @@ -11,11 +11,7 @@ #include #include -/* - * Emit the sbox as volatile const to prevent the compiler from doing - * constant folding on sbox references involving fixed indexes. - */ -static volatile const u8 ____cacheline_aligned aes_sbox[] = { +static const u8 ____cacheline_aligned aes_sbox[] = { 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, @@ -50,7 +46,7 @@ static volatile const u8 ____cacheline_aligned aes_sbox[] = { 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16, }; -static volatile const u8 ____cacheline_aligned aes_inv_sbox[] = { +static const u8 ____cacheline_aligned aes_inv_sbox[] = { 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, @@ -430,7 +426,7 @@ static void __maybe_unused aes_decrypt_generic(const u32 inv_rndkeys[], w[3] = w3; } while (--n); - aes_prefetch((const void *)aes_inv_sbox, sizeof(aes_inv_sbox)); + aes_prefetch(aes_inv_sbox, sizeof(aes_inv_sbox)); put_unaligned_le32(declast_quarterround(w, 0, *rkp++), &out[0]); put_unaligned_le32(declast_quarterround(w, 1, *rkp++), &out[4]); put_unaligned_le32(declast_quarterround(w, 2, *rkp++), &out[8]); -- 2.47.3