From d1bb1c32f945e70d2b31aad715d2e620833f55d1 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Thu, 12 Dec 2024 13:28:41 -0800
Subject: [PATCH] crypto: x86/aes-xts - make the register aliases per-function

Since aes-xts-avx-x86_64.S contains multiple functions, move the
register aliases for the parameters and local variables of the XTS
update function into the macro that generates that function.  Then add
register aliases to aes_xts_encrypt_iv() to improve readability there.
This makes aes-xts-avx-x86_64.S consistent with the GCM assembly files.

No change in the generated code.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
 arch/x86/crypto/aes-xts-avx-x86_64.S | 61 +++++++++++++++-------------
 1 file changed, 33 insertions(+), 28 deletions(-)

diff --git a/arch/x86/crypto/aes-xts-avx-x86_64.S b/arch/x86/crypto/aes-xts-avx-x86_64.S
index 580e733960522..ca69e6480cb68 100644
--- a/arch/x86/crypto/aes-xts-avx-x86_64.S
+++ b/arch/x86/crypto/aes-xts-avx-x86_64.S
@@ -80,22 +80,6 @@
 	.byte	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80
 .text
 
-// Function parameters
-.set	KEY,		%rdi	// Initially points to crypto_aes_ctx, then is
-				// advanced to point to 7th-from-last round key
-.set	SRC,		%rsi	// Pointer to next source data
-.set	DST,		%rdx	// Pointer to next destination data
-.set	LEN,		%ecx	// Remaining length in bytes
-.set	LEN8,		%cl
-.set	LEN64,		%rcx
-.set	TWEAK,		%r8	// Pointer to next tweak
-
-// %rax holds the AES key length in bytes.
-.set	KEYLEN,		%eax
-.set	KEYLEN64,	%rax
-
-// %r9-r11 are available as temporaries.
-
 .macro	_define_Vi	i
 .if VL == 16
 	.set	V\i,		%xmm\i
@@ -121,6 +105,22 @@
 .endr
 .endif
 
+	// Function parameters
+	.set	KEY,		%rdi	// Initially points to crypto_aes_ctx, then is
+					// advanced to point to 7th-from-last round key
+	.set	SRC,		%rsi	// Pointer to next source data
+	.set	DST,		%rdx	// Pointer to next destination data
+	.set	LEN,		%ecx	// Remaining length in bytes
+	.set	LEN8,		%cl
+	.set	LEN64,		%rcx
+	.set	TWEAK,		%r8	// Pointer to next tweak
+
+	// %rax holds the AES key length in bytes.
+	.set	KEYLEN,		%eax
+	.set	KEYLEN64,	%rax
+
+	// %r9-r11 are available as temporaries.
+
 	// V0-V3 hold the data blocks during the main loop, or temporary values
 	// otherwise.  V4-V5 hold temporary values.
 
@@ -728,24 +728,29 @@
 // void aes_xts_encrypt_iv(const struct crypto_aes_ctx *tweak_key,
 //			   u8 iv[AES_BLOCK_SIZE]);
 SYM_TYPED_FUNC_START(aes_xts_encrypt_iv)
-	vmovdqu		(%rsi), %xmm0
-	vpxor		(%rdi), %xmm0, %xmm0
-	movl		480(%rdi), %eax		// AES key length
-	lea		-16(%rdi, %rax, 4), %rdi
-	cmp		$24, %eax
+	.set	TWEAK_KEY,	%rdi
+	.set	IV,		%rsi
+	.set	KEYLEN,		%eax
+	.set	KEYLEN64,	%rax
+
+	vmovdqu		(IV), %xmm0
+	vpxor		(TWEAK_KEY), %xmm0, %xmm0
+	movl		480(TWEAK_KEY), KEYLEN
+	lea		-16(TWEAK_KEY, KEYLEN64, 4), TWEAK_KEY
+	cmp		$24, KEYLEN
 	jl		.Lencrypt_iv_aes128
 	je		.Lencrypt_iv_aes192
-	vaesenc		-6*16(%rdi), %xmm0, %xmm0
-	vaesenc		-5*16(%rdi), %xmm0, %xmm0
+	vaesenc		-6*16(TWEAK_KEY), %xmm0, %xmm0
+	vaesenc		-5*16(TWEAK_KEY), %xmm0, %xmm0
 .Lencrypt_iv_aes192:
-	vaesenc		-4*16(%rdi), %xmm0, %xmm0
-	vaesenc		-3*16(%rdi), %xmm0, %xmm0
+	vaesenc		-4*16(TWEAK_KEY), %xmm0, %xmm0
+	vaesenc		-3*16(TWEAK_KEY), %xmm0, %xmm0
 .Lencrypt_iv_aes128:
 .irp i, -2,-1,0,1,2,3,4,5,6
-	vaesenc		\i*16(%rdi), %xmm0, %xmm0
+	vaesenc		\i*16(TWEAK_KEY), %xmm0, %xmm0
 .endr
-	vaesenclast	7*16(%rdi), %xmm0, %xmm0
-	vmovdqu		%xmm0, (%rsi)
+	vaesenclast	7*16(TWEAK_KEY), %xmm0, %xmm0
+	vmovdqu		%xmm0, (IV)
 	RET
 SYM_FUNC_END(aes_xts_encrypt_iv)
 
-- 
2.47.2