diff options
| -rw-r--r-- | arch/x86/include/asm/hash.h | 7 | ||||
| -rw-r--r-- | arch/x86/lib/Makefile | 2 | ||||
| -rw-r--r-- | arch/x86/lib/hash.c | 88 | ||||
| -rw-r--r-- | include/asm-generic/hash.h | 9 | ||||
| -rw-r--r-- | include/linux/hash.h | 36 | ||||
| -rw-r--r-- | lib/Makefile | 2 | ||||
| -rw-r--r-- | lib/hash.c | 38 |
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 0000000..e8c58f8 --- /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 992d63b..eabcb6e 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 0000000..3056702 --- /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 0000000..05cb342 --- /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 f09a0ae..bd1754c 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 a459c31..d0f79c5 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 0000000..b89f06a --- /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); |
