linux/arch/arm64/crypto/aes-ce-core.S
Ard Biesheuvel 019cd46984 crypto: arm64/aes-ce-cipher - move assembler code to .S file
Most crypto drivers involving kernel mode NEON take care to put the code
that actually touches the NEON register file in a separate compilation
unit, to prevent the compiler from reordering code that preserves or
restores the NEON context with code that may corrupt it. This is
necessary because we currently have no way to express the restrictions
imposed upon use of the NEON in kernel mode in a way that the compiler
understands.

However, in the case of aes-ce-cipher, it did not seem unreasonable to
deviate from this rule, given how it does not seem possible for the
compiler to reorder cross object function calls with asm blocks whose
in- and output constraints reflect that it reads from and writes to
memory.

Now that LTO is being proposed for the arm64 kernel, it is time to
revisit this. The link time optimization may replace the function
calls to kernel_neon_begin() and kernel_neon_end() with instantiations
of the IR that make up its implementation, allowing further reordering
with the asm block.

So let's clean this up, and move the asm() blocks into a separate .S
file.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-By: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-29 17:33:30 +11:00

88 lines
1.8 KiB
ArmAsm

/*
* Copyright (C) 2013 - 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
.arch armv8-a+crypto
ENTRY(__aes_ce_encrypt)
sub w3, w3, #2
ld1 {v0.16b}, [x2]
ld1 {v1.4s}, [x0], #16
cmp w3, #10
bmi 0f
bne 3f
mov v3.16b, v1.16b
b 2f
0: mov v2.16b, v1.16b
ld1 {v3.4s}, [x0], #16
1: aese v0.16b, v2.16b
aesmc v0.16b, v0.16b
2: ld1 {v1.4s}, [x0], #16
aese v0.16b, v3.16b
aesmc v0.16b, v0.16b
3: ld1 {v2.4s}, [x0], #16
subs w3, w3, #3
aese v0.16b, v1.16b
aesmc v0.16b, v0.16b
ld1 {v3.4s}, [x0], #16
bpl 1b
aese v0.16b, v2.16b
eor v0.16b, v0.16b, v3.16b
st1 {v0.16b}, [x1]
ret
ENDPROC(__aes_ce_encrypt)
ENTRY(__aes_ce_decrypt)
sub w3, w3, #2
ld1 {v0.16b}, [x2]
ld1 {v1.4s}, [x0], #16
cmp w3, #10
bmi 0f
bne 3f
mov v3.16b, v1.16b
b 2f
0: mov v2.16b, v1.16b
ld1 {v3.4s}, [x0], #16
1: aesd v0.16b, v2.16b
aesimc v0.16b, v0.16b
2: ld1 {v1.4s}, [x0], #16
aesd v0.16b, v3.16b
aesimc v0.16b, v0.16b
3: ld1 {v2.4s}, [x0], #16
subs w3, w3, #3
aesd v0.16b, v1.16b
aesimc v0.16b, v0.16b
ld1 {v3.4s}, [x0], #16
bpl 1b
aesd v0.16b, v2.16b
eor v0.16b, v0.16b, v3.16b
st1 {v0.16b}, [x1]
ret
ENDPROC(__aes_ce_decrypt)
/*
* __aes_ce_sub() - use the aese instruction to perform the AES sbox
* substitution on each byte in 'input'
*/
ENTRY(__aes_ce_sub)
dup v1.4s, w0
movi v0.16b, #0
aese v0.16b, v1.16b
umov w0, v0.s[0]
ret
ENDPROC(__aes_ce_sub)
ENTRY(__aes_ce_invert)
ld1 {v0.4s}, [x1]
aesimc v1.16b, v0.16b
st1 {v1.4s}, [x0]
ret
ENDPROC(__aes_ce_invert)