sha/asm/sha512-armv4.pl: adapt for use in Linux kernel context.

Follow-up to sha256-armv4.pl in cooperation with Ard Biesheuvel
(Linaro) and Sami Tolvanen (Google).

(Imported from upstream's b1a5d1c652086257930a1f62ae51c9cdee654b2c.)

Change-Id: Ibc4f289cc8f499924ade8d6b8d494f53bc08bda7
Reviewed-on: https://boringssl-review.googlesource.com/4467
Reviewed-by: Adam Langley <agl@google.com>

crypto/sha/asm/sha512-armv4.pl

@@ -5,6 +5,8 @@
 # project. The module is, however, dual licensed under OpenSSL and
 # CRYPTOGAMS licenses depending on where you obtain it. For further
 # details see http://www.openssl.org/~appro/cryptogams/.
+#
+# Permission to use under GPL terms is granted.
 # ====================================================================
 
 # SHA512 block procedure for ARMv4. September 2007.
@@ -136,6 +138,9 @@ $code.=<<___;
 	teq	$t0,#$magic
 
 	ldr	$t3,[sp,#$Coff+0]	@ c.lo
+#if __ARM_ARCH__>=7
+	it	eq			@ Thumb2 thing, sanity check in ARM
+#endif
 	orreq	$Ktbl,$Ktbl,#1
 	@ Sigma0(x)	(ROTR((x),28) ^ ROTR((x),34) ^ ROTR((x),39))
 	@ LO		lo>>28^hi<<4  ^ hi>>2^lo<<30 ^ hi>>7^lo<<25
@@ -173,7 +178,17 @@ $code.=<<___;
 ___
 }
 $code=<<___;
-#include "arm_arch.h"
+#ifndef __KERNEL__
+# include "arm_arch.h"
+# define VFP_ABI_PUSH	vstmdb	sp!,{d8-d15}
+# define VFP_ABI_POP	vldmia	sp!,{d8-d15}
+#else
+# define __ARM_ARCH__ __LINUX_ARM_ARCH__
+# define __ARM_MAX_ARCH__ 7
+# define VFP_ABI_PUSH
+# define VFP_ABI_POP
+#endif
+
 #ifdef __ARMEL__
 # define LO 0
 # define HI 4
@@ -185,7 +200,18 @@ $code=<<___;
 #endif
 
 .text
+#if __ARM_ARCH__<7
 .code	32
+#else
+.syntax unified
+# ifdef __thumb2__
+#  define adrl adr
+.thumb
+# else
+.code   32
+# endif
+#endif
+
 .type	K512,%object
 .align	5
 K512:
@@ -230,7 +256,7 @@ WORD64(0x3c9ebe0a,0x15c9bebc, 0x431d67c4,0x9c100d4c)
 WORD64(0x4cc5d4be,0xcb3e42b6, 0x597f299c,0xfc657e2a)
 WORD64(0x5fcb6fab,0x3ad6faec, 0x6c44198c,0x4a475817)
 .size	K512,.-K512
-#if __ARM_MAX_ARCH__>=7
+#if __ARM_MAX_ARCH__>=7 && !defined(__KERNEL__)
 .LOPENSSL_armcap:
 .word	OPENSSL_armcap_P-sha512_block_data_order
 .skip	32-4
@@ -241,14 +267,18 @@ WORD64(0x5fcb6fab,0x3ad6faec, 0x6c44198c,0x4a475817)
 .global	sha512_block_data_order
 .type	sha512_block_data_order,%function
 sha512_block_data_order:
+#if __ARM_ARCH__<7
 	sub	r3,pc,#8		@ sha512_block_data_order
-	add	$len,$inp,$len,lsl#7	@ len to point at the end of inp
+#else
-#if __ARM_MAX_ARCH__>=7
+	adr	r3,sha512_block_data_order
+#endif
+#if __ARM_MAX_ARCH__>=7 && !defined(__KERNEL__)
 	ldr	r12,.LOPENSSL_armcap
 	ldr	r12,[r3,r12]		@ OPENSSL_armcap_P
 	tst	r12,#1
 	bne	.LNEON
 #endif
+	add	$len,$inp,$len,lsl#7	@ len to point at the end of inp
 	stmdb	sp!,{r4-r12,lr}
 	sub	$Ktbl,r3,#672		@ K512
 	sub	sp,sp,#9*8
@@ -362,6 +392,9 @@ $code.=<<___;
 ___
 	&BODY_00_15(0x17);
 $code.=<<___;
+#if __ARM_ARCH__>=7
+	ittt	eq			@ Thumb2 thing, sanity check in ARM
+#endif
 	ldreq	$t0,[sp,#`$Xoff+8*(16-1)`+0]
 	ldreq	$t1,[sp,#`$Xoff+8*(16-1)`+4]
 	beq	.L16_79
@@ -446,6 +479,7 @@ $code.=<<___;
 	moveq	pc,lr			@ be binary compatible with V4, yet
 	bx	lr			@ interoperable with Thumb ISA:-)
 #endif
+.size	sha512_block_data_order,.-sha512_block_data_order
 ___
 
 {
@@ -552,11 +586,15 @@ $code.=<<___;
 .arch	armv7-a
 .fpu	neon
 
+.global	sha512_block_data_order_neon
+.type	sha512_block_data_order_neon,%function
 .align	4
+sha512_block_data_order_neon:
 .LNEON:
 	dmb				@ errata #451034 on early Cortex A8
-	vstmdb	sp!,{d8-d15}		@ ABI specification says so
+	add	$len,$inp,$len,lsl#7	@ len to point at the end of inp
-	sub	$Ktbl,r3,#672		@ K512
+	VFP_ABI_PUSH
+	adrl	$Ktbl,K512
 	vldmia	$ctx,{$A-$H}		@ load context
 .Loop_neon:
 ___
@@ -581,16 +619,16 @@ $code.=<<___;
 	sub		$Ktbl,#640	@ rewind K512
 	bne		.Loop_neon
 
-	vldmia	sp!,{d8-d15}		@ epilogue
+	VFP_ABI_POP
 	ret				@ bx lr
+.size	sha512_block_data_order_neon,.-sha512_block_data_order_neon
 #endif
 ___
 }
 $code.=<<___;
-.size	sha512_block_data_order,.-sha512_block_data_order
 .asciz	"SHA512 block transform for ARMv4/NEON, CRYPTOGAMS by <appro\@openssl.org>"
 .align	2
-#if __ARM_MAX_ARCH__>=7
+#if __ARM_MAX_ARCH__>=7 && !defined(__KERNEL__)
 .comm	OPENSSL_armcap_P,4,4
 .hidden	OPENSSL_armcap_P
 #endif
@@ -599,5 +637,14 @@ ___
 $code =~ s/\`([^\`]*)\`/eval $1/gem;
 $code =~ s/\bbx\s+lr\b/.word\t0xe12fff1e/gm;	# make it possible to compile with -march=armv4
 $code =~ s/\bret\b/bx	lr/gm;
+
+open SELF,$0;
+while(<SELF>) {
+	next if (/^#!/);
+	last if (!s/^#/@/ and !/^$/);
+	print;
+}
+close SELF;
+
 print $code;
 close STDOUT; # enforce flush