[PATCH] lib/crypto: arm64/sha512-ce: Drop compatibility macros for older binutils

[Eric Biggers]

Now that the oldest supported binutils version is 2.30, the macros that
emit the SHA-512 instructions as '.inst' words are no longer needed.  So
drop them.  No change in the generated machine code.

Changed from the original patch by Ard Biesheuvel:
(https://lore.kernel.org/r/20250515142702.2592942-2-ardb+git@google.com):
 - Reduced scope to just SHA-512
 - Added comment that explains why "sha3" is used instead of "sha2"

Signed-off-by: Eric Biggers <ebiggers at kernel.org>
---

This patch is targeting libcrypto-next

 lib/crypto/arm64/sha512-ce-core.S | 27 +++++++--------------------
 1 file changed, 7 insertions(+), 20 deletions(-)

diff --git a/lib/crypto/arm64/sha512-ce-core.S b/lib/crypto/arm64/sha512-ce-core.S
index 7d870a435ea38..eaa485244af52 100644
--- a/lib/crypto/arm64/sha512-ce-core.S
+++ b/lib/crypto/arm64/sha512-ce-core.S
@@ -10,30 +10,17 @@
  */
 
 #include <linux/linkage.h>
 #include <asm/assembler.h>
 
-	.irp		b,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
-	.set		.Lq\b, \b
-	.set		.Lv\b\().2d, \b
-	.endr
-
-	.macro		sha512h, rd, rn, rm
-	.inst		0xce608000 | .L\rd | (.L\rn << 5) | (.L\rm << 16)
-	.endm
-
-	.macro		sha512h2, rd, rn, rm
-	.inst		0xce608400 | .L\rd | (.L\rn << 5) | (.L\rm << 16)
-	.endm
-
-	.macro		sha512su0, rd, rn
-	.inst		0xcec08000 | .L\rd | (.L\rn << 5)
-	.endm
-
-	.macro		sha512su1, rd, rn, rm
-	.inst		0xce608800 | .L\rd | (.L\rn << 5) | (.L\rm << 16)
-	.endm
+	/*
+	 * While SHA-512 is part of the SHA-2 family of algorithms, the
+	 * corresponding arm64 instructions are actually part of the "sha3" CPU
+	 * feature.  (Except in binutils 2.30 through 2.42, which used "sha2".
+	 * But "sha3" implies "sha2", so "sha3" still works in those versions.)
+	 */
+	.arch		armv8-a+sha3
 
 	/*
 	 * The SHA-512 round constants
 	 */
 	.section	".rodata", "a"

base-commit: 66be847cc4c2e82fb50190b52b05b3bb0ef57999
-- 
2.50.1