crypto: arm/blake2s - fix for big endian

The new ARM BLAKE2s code doesn't work correctly (fails the self-tests)
in big endian kernel builds because it doesn't swap the endianness of
the message words when loading them.  Fix this.

Fixes: 5172d322d3 ("crypto: arm/blake2s - add ARM scalar optimized BLAKE2s")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/arm/crypto/blake2s-core.S

@@ -8,6 +8,7 @@
  */
 
 #include <linux/linkage.h>
+#include <asm/assembler.h>
 
 	// Registers used to hold message words temporarily.  There aren't
 	// enough ARM registers to hold the whole message block, so we have to
@@ -38,6 +39,23 @@
 #endif
 .endm
 
+.macro _le32_bswap	a, tmp
+#ifdef __ARMEB__
+	rev_l		\a, \tmp
+#endif
+.endm
+
+.macro _le32_bswap_8x	a, b, c, d, e, f, g, h,  tmp
+	_le32_bswap	\a, \tmp
+	_le32_bswap	\b, \tmp
+	_le32_bswap	\c, \tmp
+	_le32_bswap	\d, \tmp
+	_le32_bswap	\e, \tmp
+	_le32_bswap	\f, \tmp
+	_le32_bswap	\g, \tmp
+	_le32_bswap	\h, \tmp
+.endm
+
 // Execute a quarter-round of BLAKE2s by mixing two columns or two diagonals.
 // (a0, b0, c0, d0) and (a1, b1, c1, d1) give the registers containing the two
 // columns/diagonals.  s0-s1 are the word offsets to the message words the first
@@ -180,8 +198,10 @@ ENTRY(blake2s_compress_arch)
 	tst		r1, #3
 	bne		.Lcopy_block_misaligned
 	ldmia		r1!, {r2-r9}
+	_le32_bswap_8x	r2, r3, r4, r5, r6, r7, r8, r9,  r14
 	stmia		r12!, {r2-r9}
 	ldmia		r1!, {r2-r9}
+	_le32_bswap_8x	r2, r3, r4, r5, r6, r7, r8, r9,  r14
 	stmia		r12, {r2-r9}
 .Lcopy_block_done:
 	str		r1, [sp, #68]		// Update message pointer
@@ -268,6 +288,7 @@ ENTRY(blake2s_compress_arch)
 1:
 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
 	ldr		r3, [r1], #4
+	_le32_bswap	r3, r4
 #else
 	ldrb		r3, [r1, #0]
 	ldrb		r4, [r1, #1]