<linux/hash.h>: Add support for architecture-specific functions
This is just the infrastructure; there are no users yet. This is modelled on CONFIG_ARCH_RANDOM; a CONFIG_ symbol declares the existence of <asm/hash.h>. That file may define its own versions of various functions, and define HAVE_* symbols (no CONFIG_ prefix!) to suppress the generic ones. Included is a self-test (in lib/test_hash.c) that verifies the basics. It is NOT in general required that the arch-specific functions compute the same thing as the generic, but if a HAVE_* symbol is defined with the value 1, then equality is tested. Signed-off-by: George Spelvin <linux@sciencehorizons.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Andreas Schwab <schwab@linux-m68k.org> Cc: Philippe De Muyter <phdm@macq.eu> Cc: linux-m68k@lists.linux-m68k.org Cc: Alistair Francis <alistai@xilinx.com> Cc: Michal Simek <michal.simek@xilinx.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: uclinux-h8-devel@lists.sourceforge.jphifive-unleashed-5.1
George Spelvin
parent
2a18da7a9c
commit
468a942852
|
|
@ -589,6 +589,14 @@ config HAVE_STACK_VALIDATION
|
|||
Architecture supports the 'objtool check' host tool command, which
|
||||
performs compile-time stack metadata validation.
|
||||
|
||||
config HAVE_ARCH_HASH
|
||||
bool
|
||||
default n
|
||||
help
|
||||
If this is set, the architecture provides an <asm/hash.h>
|
||||
file which provides platform-specific implementations of some
|
||||
functions in <linux/hash.h> or fs/namei.c.
|
||||
|
||||
#
|
||||
# ABI hall of shame
|
||||
#
|
||||
|
|
|
|||
|
|
@ -1788,7 +1788,11 @@ static int walk_component(struct nameidata *nd, int flags)
|
|||
|
||||
#include <asm/word-at-a-time.h>
|
||||
|
||||
#ifdef CONFIG_64BIT
|
||||
#ifdef HASH_MIX
|
||||
|
||||
/* Architecture provides HASH_MIX and fold_hash() in <asm/hash.h> */
|
||||
|
||||
#elif defined(CONFIG_64BIT)
|
||||
/*
|
||||
* Register pressure in the mixing function is an issue, particularly
|
||||
* on 32-bit x86, but almost any function requires one state value and
|
||||
|
|
|
|||
|
|
@ -41,19 +41,40 @@
|
|||
#define GOLDEN_RATIO_32 0x61C88647
|
||||
#define GOLDEN_RATIO_64 0x61C8864680B583EBull
|
||||
|
||||
#ifdef CONFIG_HAVE_ARCH_HASH
|
||||
/* This header may use the GOLDEN_RATIO_xx constants */
|
||||
#include <asm/hash.h>
|
||||
#endif
|
||||
|
||||
static inline u32 __hash_32(u32 val)
|
||||
/*
|
||||
* The _generic versions exist only so lib/test_hash.c can compare
|
||||
* the arch-optimized versions with the generic.
|
||||
*
|
||||
* Note that if you change these, any <asm/hash.h> that aren't updated
|
||||
* to match need to have their HAVE_ARCH_* define values updated so the
|
||||
* self-test will not false-positive.
|
||||
*/
|
||||
#ifndef HAVE_ARCH__HASH_32
|
||||
#define __hash_32 __hash_32_generic
|
||||
#endif
|
||||
static inline u32 __hash_32_generic(u32 val)
|
||||
{
|
||||
return val * GOLDEN_RATIO_32;
|
||||
}
|
||||
|
||||
static inline u32 hash_32(u32 val, unsigned int bits)
|
||||
#ifndef HAVE_ARCH_HASH_32
|
||||
#define hash_32 hash_32_generic
|
||||
#endif
|
||||
static inline u32 hash_32_generic(u32 val, unsigned int bits)
|
||||
{
|
||||
/* High bits are more random, so use them. */
|
||||
return __hash_32(val) >> (32 - bits);
|
||||
}
|
||||
|
||||
static __always_inline u32 hash_64(u64 val, unsigned int bits)
|
||||
#ifndef HAVE_ARCH_HASH_64
|
||||
#define hash_64 hash_64_generic
|
||||
#endif
|
||||
static __always_inline u32 hash_64_generic(u64 val, unsigned int bits)
|
||||
{
|
||||
#if BITS_PER_LONG == 64
|
||||
/* 64x64-bit multiply is efficient on all 64-bit processors */
|
||||
|
|
|
|||
|
|
@ -1815,6 +1815,17 @@ config TEST_RHASHTABLE
|
|||
|
||||
If unsure, say N.
|
||||
|
||||
config TEST_HASH
|
||||
tristate "Perform selftest on hash functions"
|
||||
default n
|
||||
help
|
||||
Enable this option to test the kernel's integer (<linux/hash,h>)
|
||||
and string (<linux/stringhash.h>) hash functions on boot
|
||||
(or module load).
|
||||
|
||||
This is intended to help people writing architecture-specific
|
||||
optimized versions. If unsure, say N.
|
||||
|
||||
endmenu # runtime tests
|
||||
|
||||
config PROVIDE_OHCI1394_DMA_INIT
|
||||
|
|
|
|||
|
|
@ -48,6 +48,7 @@ obj-$(CONFIG_TEST_HEXDUMP) += test_hexdump.o
|
|||
obj-y += kstrtox.o
|
||||
obj-$(CONFIG_TEST_BPF) += test_bpf.o
|
||||
obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
|
||||
obj-$(CONFIG_TEST_HASH) += test_hash.o
|
||||
obj-$(CONFIG_TEST_KASAN) += test_kasan.o
|
||||
obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o
|
||||
obj-$(CONFIG_TEST_LKM) += test_module.o
|
||||
|
|
|
|||
|
|
@ -0,0 +1,250 @@
|
|||
/*
|
||||
* Test cases for <linux/hash.h> and <linux/stringhash.h>
|
||||
* This just verifies that various ways of computing a hash
|
||||
* produce the same thing and, for cases where a k-bit hash
|
||||
* value is requested, is of the requested size.
|
||||
*
|
||||
* We fill a buffer with a 255-byte null-terminated string,
|
||||
* and use both full_name_hash() and hashlen_string() to hash the
|
||||
* substrings from i to j, where 0 <= i < j < 256.
|
||||
*
|
||||
* The returned values are used to check that __hash_32() and
|
||||
* __hash_32_generic() compute the same thing. Likewise hash_32()
|
||||
* and hash_64().
|
||||
*/
|
||||
|
||||
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt "\n"
|
||||
|
||||
#include <linux/compiler.h>
|
||||
#include <linux/types.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/hash.h>
|
||||
#include <linux/stringhash.h>
|
||||
#include <linux/printk.h>
|
||||
|
||||
/* 32-bit XORSHIFT generator. Seed must not be zero. */
|
||||
static u32 __init __attribute_const__
|
||||
xorshift(u32 seed)
|
||||
{
|
||||
seed ^= seed << 13;
|
||||
seed ^= seed >> 17;
|
||||
seed ^= seed << 5;
|
||||
return seed;
|
||||
}
|
||||
|
||||
/* Given a non-zero x, returns a non-zero byte. */
|
||||
static u8 __init __attribute_const__
|
||||
mod255(u32 x)
|
||||
{
|
||||
x = (x & 0xffff) + (x >> 16); /* 1 <= x <= 0x1fffe */
|
||||
x = (x & 0xff) + (x >> 8); /* 1 <= x <= 0x2fd */
|
||||
x = (x & 0xff) + (x >> 8); /* 1 <= x <= 0x100 */
|
||||
x = (x & 0xff) + (x >> 8); /* 1 <= x <= 0xff */
|
||||
return x;
|
||||
}
|
||||
|
||||
/* Fill the buffer with non-zero bytes. */
|
||||
static void __init
|
||||
fill_buf(char *buf, size_t len, u32 seed)
|
||||
{
|
||||
size_t i;
|
||||
|
||||
for (i = 0; i < len; i++) {
|
||||
seed = xorshift(seed);
|
||||
buf[i] = mod255(seed);
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Test the various integer hash functions. h64 (or its low-order bits)
|
||||
* is the integer to hash. hash_or accumulates the OR of the hash values,
|
||||
* which are later checked to see that they cover all the requested bits.
|
||||
*
|
||||
* Because these functions (as opposed to the string hashes) are all
|
||||
* inline, the code being tested is actually in the module, and you can
|
||||
* recompile and re-test the module without rebooting.
|
||||
*/
|
||||
static bool __init
|
||||
test_int_hash(unsigned long long h64, u32 hash_or[2][33])
|
||||
{
|
||||
int k;
|
||||
u32 h0 = (u32)h64, h1, h2;
|
||||
|
||||
/* Test __hash32 */
|
||||
hash_or[0][0] |= h1 = __hash_32(h0);
|
||||
#ifdef HAVE_ARCH__HASH_32
|
||||
hash_or[1][0] |= h2 = __hash_32_generic(h0);
|
||||
#if HAVE_ARCH__HASH_32 == 1
|
||||
if (h1 != h2) {
|
||||
pr_err("__hash_32(%#x) = %#x != __hash_32_generic() = %#x",
|
||||
h0, h1, h2);
|
||||
return false;
|
||||
}
|
||||
#endif
|
||||
#endif
|
||||
|
||||
/* Test k = 1..32 bits */
|
||||
for (k = 1; k <= 32; k++) {
|
||||
u32 const m = ((u32)2 << (k-1)) - 1; /* Low k bits set */
|
||||
|
||||
/* Test hash_32 */
|
||||
hash_or[0][k] |= h1 = hash_32(h0, k);
|
||||
if (h1 > m) {
|
||||
pr_err("hash_32(%#x, %d) = %#x > %#x", h0, k, h1, m);
|
||||
return false;
|
||||
}
|
||||
#ifdef HAVE_ARCH_HASH_32
|
||||
h2 = hash_32_generic(h0, k);
|
||||
#if HAVE_ARCH_HASH_32 == 1
|
||||
if (h1 != h2) {
|
||||
pr_err("hash_32(%#x, %d) = %#x != hash_32_generic() "
|
||||
" = %#x", h0, k, h1, h2);
|
||||
return false;
|
||||
}
|
||||
#else
|
||||
if (h2 > m) {
|
||||
pr_err("hash_32_generic(%#x, %d) = %#x > %#x",
|
||||
h0, k, h1, m);
|
||||
return false;
|
||||
}
|
||||
#endif
|
||||
#endif
|
||||
/* Test hash_64 */
|
||||
hash_or[1][k] |= h1 = hash_64(h64, k);
|
||||
if (h1 > m) {
|
||||
pr_err("hash_64(%#llx, %d) = %#x > %#x", h64, k, h1, m);
|
||||
return false;
|
||||
}
|
||||
#ifdef HAVE_ARCH_HASH_64
|
||||
h2 = hash_64_generic(h64, k);
|
||||
#if HAVE_ARCH_HASH_64 == 1
|
||||
if (h1 != h2) {
|
||||
pr_err("hash_64(%#llx, %d) = %#x != hash_64_generic() "
|
||||
"= %#x", h64, k, h1, h2);
|
||||
return false;
|
||||
}
|
||||
#else
|
||||
if (h2 > m) {
|
||||
pr_err("hash_64_generic(%#llx, %d) = %#x > %#x",
|
||||
h64, k, h1, m);
|
||||
return false;
|
||||
}
|
||||
#endif
|
||||
#endif
|
||||
}
|
||||
|
||||
(void)h2; /* Suppress unused variable warning */
|
||||
return true;
|
||||
}
|
||||
|
||||
#define SIZE 256 /* Run time is cubic in SIZE */
|
||||
|
||||
static int __init
|
||||
test_hash_init(void)
|
||||
{
|
||||
char buf[SIZE+1];
|
||||
u32 string_or = 0, hash_or[2][33] = { 0 };
|
||||
unsigned tests = 0;
|
||||
unsigned long long h64 = 0;
|
||||
int i, j;
|
||||
|
||||
fill_buf(buf, SIZE, 1);
|
||||
|
||||
/* Test every possible non-empty substring in the buffer. */
|
||||
for (j = SIZE; j > 0; --j) {
|
||||
buf[j] = '\0';
|
||||
|
||||
for (i = 0; i <= j; i++) {
|
||||
u64 hashlen = hashlen_string(buf+i);
|
||||
u32 h0 = full_name_hash(buf+i, j-i);
|
||||
|
||||
/* Check that hashlen_string gets the length right */
|
||||
if (hashlen_len(hashlen) != j-i) {
|
||||
pr_err("hashlen_string(%d..%d) returned length"
|
||||
" %u, expected %d",
|
||||
i, j, hashlen_len(hashlen), j-i);
|
||||
return -EINVAL;
|
||||
}
|
||||
/* Check that the hashes match */
|
||||
if (hashlen_hash(hashlen) != h0) {
|
||||
pr_err("hashlen_string(%d..%d) = %08x != "
|
||||
"full_name_hash() = %08x",
|
||||
i, j, hashlen_hash(hashlen), h0);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
string_or |= h0;
|
||||
h64 = h64 << 32 | h0; /* For use with hash_64 */
|
||||
if (!test_int_hash(h64, hash_or))
|
||||
return -EINVAL;
|
||||
tests++;
|
||||
} /* i */
|
||||
} /* j */
|
||||
|
||||
/* The OR of all the hash values should cover all the bits */
|
||||
if (~string_or) {
|
||||
pr_err("OR of all string hash results = %#x != %#x",
|
||||
string_or, -1u);
|
||||
return -EINVAL;
|
||||
}
|
||||
if (~hash_or[0][0]) {
|
||||
pr_err("OR of all __hash_32 results = %#x != %#x",
|
||||
hash_or[0][0], -1u);
|
||||
return -EINVAL;
|
||||
}
|
||||
#ifdef HAVE_ARCH__HASH_32
|
||||
#if HAVE_ARCH__HASH_32 != 1 /* Test is pointless if results match */
|
||||
if (~hash_or[1][0]) {
|
||||
pr_err("OR of all __hash_32_generic results = %#x != %#x",
|
||||
hash_or[1][0], -1u);
|
||||
return -EINVAL;
|
||||
}
|
||||
#endif
|
||||
#endif
|
||||
|
||||
/* Likewise for all the i-bit hash values */
|
||||
for (i = 1; i <= 32; i++) {
|
||||
u32 const m = ((u32)2 << (i-1)) - 1; /* Low i bits set */
|
||||
|
||||
if (hash_or[0][i] != m) {
|
||||
pr_err("OR of all hash_32(%d) results = %#x "
|
||||
"(%#x expected)", i, hash_or[0][i], m);
|
||||
return -EINVAL;
|
||||
}
|
||||
if (hash_or[1][i] != m) {
|
||||
pr_err("OR of all hash_64(%d) results = %#x "
|
||||
"(%#x expected)", i, hash_or[1][i], m);
|
||||
return -EINVAL;
|
||||
}
|
||||
}
|
||||
|
||||
/* Issue notices about skipped tests. */
|
||||
#ifndef HAVE_ARCH__HASH_32
|
||||
pr_info("__hash_32() has no arch implementation to test.");
|
||||
#elif HAVE_ARCH__HASH_32 != 1
|
||||
pr_info("__hash_32() is arch-specific; not compared to generic.");
|
||||
#endif
|
||||
#ifndef HAVE_ARCH_HASH_32
|
||||
pr_info("hash_32() has no arch implementation to test.");
|
||||
#elif HAVE_ARCH_HASH_32 != 1
|
||||
pr_info("hash_32() is arch-specific; not compared to generic.");
|
||||
#endif
|
||||
#ifndef HAVE_ARCH_HASH_64
|
||||
pr_info("hash_64() has no arch implementation to test.");
|
||||
#elif HAVE_ARCH_HASH_64 != 1
|
||||
pr_info("hash_64() is arch-specific; not compared to generic.");
|
||||
#endif
|
||||
|
||||
pr_notice("%u tests passed.", tests);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void __exit test_hash_exit(void)
|
||||
{
|
||||
}
|
||||
|
||||
module_init(test_hash_init); /* Does everything */
|
||||
module_exit(test_hash_exit); /* Does nothing */
|
||||
|
||||
MODULE_LICENSE("GPL");
|
||||
Loading…
Reference in New Issue