forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
257 lines
6.3 KiB
257 lines
6.3 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
|
* 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, buf+i); |
|
u32 h0 = full_name_hash(buf+i, 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. */ |
|
#ifdef HAVE_ARCH__HASH_32 |
|
#if HAVE_ARCH__HASH_32 != 1 |
|
pr_info("__hash_32() is arch-specific; not compared to generic."); |
|
#endif |
|
#else |
|
pr_info("__hash_32() has no arch implementation to test."); |
|
#endif |
|
#ifdef HAVE_ARCH_HASH_32 |
|
#if HAVE_ARCH_HASH_32 != 1 |
|
pr_info("hash_32() is arch-specific; not compared to generic."); |
|
#endif |
|
#else |
|
pr_info("hash_32() has no arch implementation to test."); |
|
#endif |
|
#ifdef HAVE_ARCH_HASH_64 |
|
#if HAVE_ARCH_HASH_64 != 1 |
|
pr_info("hash_64() is arch-specific; not compared to generic."); |
|
#endif |
|
#else |
|
pr_info("hash_64() has no arch implementation to test."); |
|
#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");
|
|
|