summaryrefslogtreecommitdiff
path: root/lib/raid6/neon.c
diff options
context:
space:
mode:
authorArd Biesheuvel <ard.biesheuvel@linaro.org>2013-05-16 17:20:32 +0200
committerArd Biesheuvel <ard.biesheuvel@linaro.org>2013-07-08 22:09:18 +0100
commit7d11965ddb9b9b1e0a5d13c58345ada1ccbc663b (patch)
tree9aec7ff11372f0194f288c13c7c83ff6ef40c87b /lib/raid6/neon.c
parent01956597cbc46df072f20f90a40eebe356200c38 (diff)
lib/raid6: add ARM-NEON accelerated syndrome calculation
Rebased/reworked a patch contributed by Rob Herring that uses NEON intrinsics to perform the RAID-6 syndrome calculations. It uses the existing unroll.awk code to generate several unrolled versions of which the best performing one is selected at boot time. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Nicolas Pitre <nico@linaro.org> Cc: hpa@linux.intel.com
Diffstat (limited to 'lib/raid6/neon.c')
-rw-r--r--lib/raid6/neon.c58
1 files changed, 58 insertions, 0 deletions
diff --git a/lib/raid6/neon.c b/lib/raid6/neon.c
new file mode 100644
index 000000000000..36ad4705df1a
--- /dev/null
+++ b/lib/raid6/neon.c
@@ -0,0 +1,58 @@
+/*
+ * linux/lib/raid6/neon.c - RAID6 syndrome calculation using ARM NEON intrinsics
+ *
+ * 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/pq.h>
+
+#ifdef __KERNEL__
+#include <asm/neon.h>
+#else
+#define kernel_neon_begin()
+#define kernel_neon_end()
+#define cpu_has_neon() (1)
+#endif
+
+/*
+ * There are 2 reasons these wrappers are kept in a separate compilation unit
+ * from the actual implementations in neonN.c (generated from neon.uc by
+ * unroll.awk):
+ * - the actual implementations use NEON intrinsics, and the GCC support header
+ * (arm_neon.h) is not fully compatible (type wise) with the kernel;
+ * - the neonN.c files are compiled with -mfpu=neon and optimization enabled,
+ * and we have to make sure that we never use *any* NEON/VFP instructions
+ * outside a kernel_neon_begin()/kernel_neon_end() pair.
+ */
+
+#define RAID6_NEON_WRAPPER(_n) \
+ static void raid6_neon ## _n ## _gen_syndrome(int disks, \
+ size_t bytes, void **ptrs) \
+ { \
+ void raid6_neon ## _n ## _gen_syndrome_real(int, \
+ unsigned long, void**); \
+ kernel_neon_begin(); \
+ raid6_neon ## _n ## _gen_syndrome_real(disks, \
+ (unsigned long)bytes, ptrs); \
+ kernel_neon_end(); \
+ } \
+ struct raid6_calls const raid6_neonx ## _n = { \
+ raid6_neon ## _n ## _gen_syndrome, \
+ raid6_have_neon, \
+ "neonx" #_n, \
+ 0 \
+ }
+
+static int raid6_have_neon(void)
+{
+ return cpu_has_neon();
+}
+
+RAID6_NEON_WRAPPER(1);
+RAID6_NEON_WRAPPER(2);
+RAID6_NEON_WRAPPER(4);
+RAID6_NEON_WRAPPER(8);