linux-kernel - [PATCH] arm64/crypto: remove non-standard notation

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Message-Id: <20180820224032.53194-1-ndesaulniers@google.com>
Date:   Mon, 20 Aug 2018 15:40:32 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     ard.biesheuvel@...aro.org
Cc:     Nick Desaulniers <ndesaulniers@...gle.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        linux-crypto@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] arm64/crypto: remove non-standard notation

It seems that:
ldr q8, =0x30000000200000001

is a GNU as convience notation for:
ldr q8, .Lconstant
.Lconstant
.word 0x00000001
.word 0x00000002
.word 0x00000003
.word 0x00000000

based on this comment in binutils' source [0]. I've asked for this
non-standard convience notation to be added to other assemblers [1], but
until then, we can remove it and get equivalent disassembly:

before:
00000000000009d4 <neon_aes_ctr_encrypt>:
...
     a48:       9c000ac8        ldr     q8, ba0 <neon_aes_ctr_encrypt+0x1cc>
...
     ba0:       00000001        .word   0x00000001
     ba4:       00000002        .word   0x00000002
     ba8:       00000003        .word   0x00000003
     bac:       00000000        .word   0x00000000

after:

00000000000009d4 <neon_aes_ctr_encrypt>:
...
     a48:       9c000aa8        ldr     q8, b9c <neon_aes_ctr_encrypt+0x1c8>
...
     b9c:       00000001        .word   0x00000001
     ba0:       00000002        .word   0x00000002
     ba4:       00000003        .word   0x00000003
     ba8:       00000000        .word   0x00000000

[0] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=blob;f=gas/testsuite/gas/aarch64/programmer-friendly.s;h=6254c6476efdc848648b05068be0574e7addc85d;hb=HEAD#l11
[1] https://bugs.llvm.org/show_bug.cgi?id=38642

Signed-off-by: Nick Desaulniers <ndesaulniers@...gle.com>
---
 arch/arm64/crypto/aes-modes.S | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/crypto/aes-modes.S b/arch/arm64/crypto/aes-modes.S
index 483a7130cf0e..9288c5b0eca2 100644
--- a/arch/arm64/crypto/aes-modes.S
+++ b/arch/arm64/crypto/aes-modes.S
@@ -232,7 +232,7 @@ AES_ENTRY(aes_ctr_encrypt)
 	bmi		.Lctr1x
 	cmn		w6, #4			/* 32 bit overflow? */
 	bcs		.Lctr1x
-	ldr		q8, =0x30000000200000001	/* addends 1,2,3[,0] */
+	ldr		q8, .Laddends /* addends 1,2,3[,0] */
 	dup		v7.4s, w6
 	mov		v0.16b, v4.16b
 	add		v7.4s, v7.4s, v8.4s
@@ -295,6 +295,12 @@ AES_ENTRY(aes_ctr_encrypt)
 	rev		x7, x7
 	ins		v4.d[0], x7
 	b		.Lctrcarrydone
+
+.Laddends:
+	.word	0x00000001
+	.word	0x00000002
+	.word	0x00000003
+	.word	0x00000000
 AES_ENDPROC(aes_ctr_encrypt)
 	.ltorg
 
-- 
2.18.0.865.gffc8e1a3cd6-goog