[PATCH v2 4/8] crypto: x86/aes-xts - make the register aliases per-function

[Eric Biggers <ebiggers@kernel.org>]

From: Eric Biggers <ebiggers@google.com>

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>
---
 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 580e73396052..ca69e6480cb6 100644
--- a/arch/x86/crypto/aes-xts-avx-x86_64.S
+++ b/arch/x86/crypto/aes-xts-avx-x86_64.S
@@ -78,26 +78,10 @@
 	.byte	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
 	.byte	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80
 	.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
 .elseif VL == 32
 	.set	V\i,		%ymm\i
@@ -119,10 +103,26 @@
 .irp i, 16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31
 	_define_Vi	\i
 .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.
 
 	// V6-V9 hold XTS tweaks.  Each 128-bit lane holds one tweak.
 	.set	TWEAK0_XMM,	%xmm6
@@ -726,28 +726,33 @@
 .endm
 
 // 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)
 
 // Below are the actual AES-XTS encryption and decryption functions,
 // instantiated from the above macro.  They all have the following prototype:
-- 
2.47.1