ARM: crypto: add NEON accelerated XOR implementation

Add a source file xor-neon.c (which is really just the reference
C implementation passed through the GCC vectorizer) and hook it
up to the XOR framework.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/arch/arm/lib/xor-neon.c b/arch/arm/lib/xor-neon.c
new file mode 100644
index 000000000000..f485e5a2af4b
--- /dev/null
+++ b/arch/arm/lib/xor-neon.c
@@ -0,0 +1,42 @@
+/*
+ * linux/arch/arm/lib/xor-neon.c
+ *
+ * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/raid/xor.h>
+
+#ifndef __ARM_NEON__
+#error You should compile this file with '-mfloat-abi=softfp -mfpu=neon'
+#endif
+
+/*
+ * Pull in the reference implementations while instructing GCC (through
+ * -ftree-vectorize) to attempt to exploit implicit parallelism and emit
+ * NEON instructions.
+ */
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
+#pragma GCC optimize "tree-vectorize"
+#else
+/*
+ * While older versions of GCC do not generate incorrect code, they fail to
+ * recognize the parallel nature of these functions, and emit plain ARM code,
+ * which is known to be slower than the optimized ARM code in asm-arm/xor.h.
+ */
+#warning This code requires at least version 4.6 of GCC
+#endif
+
+#pragma GCC diagnostic ignored "-Wunused-variable"
+#include <asm-generic/xor.h>
+
+struct xor_block_template const xor_block_neon_inner = {
+        .name   = "__inner_neon__",
+        .do_2   = xor_8regs_2,
+        .do_3   = xor_8regs_3,
+        .do_4   = xor_8regs_4,
+        .do_5   = xor_8regs_5,
+};