7 files changed, 180 insertions, 2 deletions

diff --git a/arch/x86/include/asm/hash.h b/arch/x86/include/asm/hash.h
new file mode 100644
index 000000000000..e8c58f88b1d4
--- /dev/null
+++ b/arch/x86/include/asm/hash.h
@@ -0,0 +1,7 @@
+#ifndef _ASM_X86_HASH_H
+#define _ASM_X86_HASH_H
+
+struct fast_hash_ops;
+extern void setup_arch_fast_hash(struct fast_hash_ops *ops);
+
+#endif /* _ASM_X86_HASH_H */
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 992d63bb154f..eabcb6e6a900 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -24,7 +24,7 @@ lib-$(CONFIG_SMP) += rwlock.o
 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
 lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o
 
-obj-y += msr.o msr-reg.o msr-reg-export.o
+obj-y += msr.o msr-reg.o msr-reg-export.o hash.o
 
 ifeq ($(CONFIG_X86_32),y)
         obj-y += atomic64_32.o
diff --git a/arch/x86/lib/hash.c b/arch/x86/lib/hash.c
new file mode 100644
index 000000000000..3056702e81fb
--- /dev/null
+++ b/arch/x86/lib/hash.c
@@ -0,0 +1,88 @@
+/*
+ * 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/hash.h>
+
+#include <asm/processor.h>
+#include <asm/cpufeature.h>
+#include <asm/hash.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;
+        }
+}
diff --git a/include/asm-generic/hash.h b/include/asm-generic/hash.h
new file mode 100644
index 000000000000..05cb3421ee7e
--- /dev/null
+++ b/include/asm-generic/hash.h
@@ -0,0 +1,9 @@
+#ifndef __ASM_GENERIC_HASH_H
+#define __ASM_GENERIC_HASH_H
+
+struct arch_hash_ops;
+static inline void setup_arch_fast_hash(struct arch_hash_ops *ops)
+{
+}
+
+#endif /* __ASM_GENERIC_HASH_H */
diff --git a/include/linux/hash.h b/include/linux/hash.h
index f09a0ae4d858..bd1754c7ecef 100644
--- a/include/linux/hash.h
+++ b/include/linux/hash.h
@@ -15,6 +15,7 @@
  */
 
 #include <asm/types.h>
+#include <asm/hash.h>
 #include <linux/compiler.h>
 
 /* 2^31 + 2^29 - 2^25 + 2^22 - 2^19 - 2^16 + 1 */
@@ -78,4 +79,39 @@ static inline u32 hash32_ptr(const void *ptr)
 #endif
         return (u32)val;
 }
+
+struct fast_hash_ops {
+        u32 (*hash)(const void *data, u32 len, u32 seed);
+        u32 (*hash2)(const u32 *data, u32 len, u32 seed);
+};
+
+/**
+ *      arch_fast_hash - Caclulates a hash over a given buffer that can have
+ *                       arbitrary size. This function will eventually use an
+ *                       architecture-optimized hashing implementation if
+ *                       available, and trades off distribution for speed.
+ *
+ *      @data: buffer to hash
+ *      @len: length of buffer in bytes
+ *      @seed: start seed
+ *
+ *      Returns 32bit hash.
+ */
+extern u32 arch_fast_hash(const void *data, u32 len, u32 seed);
+
+/**
+ *      arch_fast_hash2 - Caclulates a hash over a given buffer that has a
+ *                        size that is of a multiple of 32bit words. This
+ *                        function will eventually use an architecture-
+ *                        optimized hashing implementation if available,
+ *                        and trades off distribution for speed.
+ *
+ *      @data: buffer to hash (must be 32bit padded)
+ *      @len: number of 32bit words
+ *      @seed: start seed
+ *
+ *      Returns 32bit hash.
+ */
+extern u32 arch_fast_hash2(const u32 *data, u32 len, u32 seed);
+
 #endif /* _LINUX_HASH_H */
diff --git a/lib/Makefile b/lib/Makefile
index a459c31e8c6b..d0f79c547d97 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -26,7 +26,7 @@ obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
          bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \
          gcd.o lcm.o list_sort.o uuid.o flex_array.o iovec.o clz_ctz.o \
          bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o \
-         percpu-refcount.o percpu_ida.o
+         percpu-refcount.o percpu_ida.o hash.o
 obj-y += string_helpers.o
 obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
 obj-y += kstrtox.o
diff --git a/lib/hash.c b/lib/hash.c
new file mode 100644
index 000000000000..b89f06a2d606
--- /dev/null
+++ b/lib/hash.c
@@ -0,0 +1,38 @@
+/* General purpose hashing library
+ *
+ * That's a start of a kernel hashing library, which can be extended
+ * with further algorithms in future. arch_fast_hash{2,}() will
+ * eventually resolve to an architecture optimized implementation.
+ *
+ * Copyright 2013 Francesco Fusco <ffusco@redhat.com>
+ * Copyright 2013 Daniel Borkmann <dborkman@redhat.com>
+ * Copyright 2013 Thomas Graf <tgraf@redhat.com>
+ * Licensed under the GNU General Public License, version 2.0 (GPLv2)
+ */
+
+#include <linux/jhash.h>
+#include <linux/hash.h>
+
+static struct fast_hash_ops arch_hash_ops __read_mostly = {
+        .hash  = jhash,
+        .hash2 = jhash2,
+};
+
+u32 arch_fast_hash(const void *data, u32 len, u32 seed)
+{
+        return arch_hash_ops.hash(data, len, seed);
+}
+EXPORT_SYMBOL_GPL(arch_fast_hash);
+
+u32 arch_fast_hash2(const u32 *data, u32 len, u32 seed)
+{
+        return arch_hash_ops.hash2(data, len, seed);
+}
+EXPORT_SYMBOL_GPL(arch_fast_hash2);
+
+static int __init hashlib_init(void)
+{
+        setup_arch_fast_hash(&arch_hash_ops);
+        return 0;
+}
+early_initcall(hashlib_init);