datapath: Backport for architecture hash library.

[sliver-openvswitch.git] / datapath / linux / compat / hash-x86.c

diff --git a/datapath/linux/compat/hash-x86.c b/datapath/linux/compat/hash-x86.c
new file mode 100644 (file)
index 0000000..ca259b9
--- /dev/null
+++ b/datapath/linux/compat/hash-x86.c
@@ -0,0 +1,95 @@
+/*
+ * Some portions derived from code covered by the following notice:
+ *
+ * Copyright (c) 2010-2013 Intel Corporation. All rights reserved.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *   * Neither the name of Intel Corporation nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/version.h>
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3,14,0)
+
+#ifdef CONFIG_X86
+
+#include <linux/hash.h>
+
+#include <asm/processor.h>
+#include <asm/cpufeature.h>
+
+static inline u32 crc32_u32(u32 crc, u32 val)
+{
+       asm ("crc32l %1,%0\n" : "+r" (crc) : "rm" (val));
+       return crc;
+}
+
+static u32 intel_crc4_2_hash(const void *data, u32 len, u32 seed)
+{
+       const u32 *p32 = (const u32 *) data;
+       u32 i, tmp = 0;
+
+       for (i = 0; i < len / 4; i++)
+               seed = crc32_u32(*p32++, seed);
+
+       switch (3 - (len & 0x03)) {
+       case 0:
+               tmp |= *((const u8 *) p32 + 2) << 16;
+               /* fallthrough */
+       case 1:
+               tmp |= *((const u8 *) p32 + 1) << 8;
+               /* fallthrough */
+       case 2:
+               tmp |= *((const u8 *) p32);
+               seed = crc32_u32(tmp, seed);
+       default:
+               break;
+       }
+
+       return seed;
+}
+
+static u32 intel_crc4_2_hash2(const u32 *data, u32 len, u32 seed)
+{
+       const u32 *p32 = (const u32 *) data;
+       u32 i;
+
+       for (i = 0; i < len; i++)
+               seed = crc32_u32(*p32++, seed);
+
+       return seed;
+}
+
+void setup_arch_fast_hash(struct fast_hash_ops *ops)
+{
+       if (cpu_has_xmm4_2) {
+               ops->hash  = intel_crc4_2_hash;
+               ops->hash2 = intel_crc4_2_hash2;
+       }
+}
+
+#endif /* CONFIG_X86 */
+#endif /* < 3.14 */