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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240// 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(). */
#include <linux/compiler.h>#include <linux/types.h>#include <linux/module.h>#include <linux/hash.h>#include <linux/stringhash.h>#include <kunit/test.h>
/* 32-bit XORSHIFT generator. Seed must not be zero. */static u32 __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 __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 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); }}
/* Holds most testing variables for the int test. */struct test_hash_params { /* Pointer to integer to be hashed. */ unsigned long long *h64; /* Low 32-bits of integer to be hashed. */ u32 h0; /* Arch-specific hash result. */ u32 h1; /* Generic hash result. */ u32 h2; /* ORed hashes of given size (in bits). */ u32 (*hash_or)[33];};
#ifdef HAVE_ARCH__HASH_32static voidtest_int__hash_32(struct kunit *test, struct test_hash_params *params){ params->hash_or[1][0] |= params->h2 = __hash_32_generic(params->h0);#if HAVE_ARCH__HASH_32 == 1 KUNIT_EXPECT_EQ_MSG(test, params->h1, params->h2, "__hash_32(%#x) = %#x != __hash_32_generic() = %#x", params->h0, params->h1, params->h2);#endif}#endif
#ifdef HAVE_ARCH_HASH_64static voidtest_int_hash_64(struct kunit *test, struct test_hash_params *params, u32 const *m, int *k){ params->h2 = hash_64_generic(*params->h64, *k);#if HAVE_ARCH_HASH_64 == 1 KUNIT_EXPECT_EQ_MSG(test, params->h1, params->h2, "hash_64(%#llx, %d) = %#x != hash_64_generic() = %#x", *params->h64, *k, params->h1, params->h2);#else KUNIT_EXPECT_LE_MSG(test, params->h1, params->h2, "hash_64_generic(%#llx, %d) = %#x > %#x", *params->h64, *k, params->h1, *m);#endif}#endif
/* * 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 voidtest_int_hash(struct kunit *test, unsigned long long h64, u32 hash_or[2][33]){ int k; struct test_hash_params params = { &h64, (u32)h64, 0, 0, hash_or };
/* Test __hash32 */ hash_or[0][0] |= params.h1 = __hash_32(params.h0);#ifdef HAVE_ARCH__HASH_32 test_int__hash_32(test, ¶ms);#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] |= params.h1 = hash_32(params.h0, k); KUNIT_EXPECT_LE_MSG(test, params.h1, m, "hash_32(%#x, %d) = %#x > %#x", params.h0, k, params.h1, m);
/* Test hash_64 */ hash_or[1][k] |= params.h1 = hash_64(h64, k); KUNIT_EXPECT_LE_MSG(test, params.h1, m, "hash_64(%#llx, %d) = %#x > %#x", h64, k, params.h1, m);#ifdef HAVE_ARCH_HASH_64 test_int_hash_64(test, ¶ms, &m, &k);#endif }}
#define SIZE 256 /* Run time is cubic in SIZE */
static void test_string_or(struct kunit *test){ char buf[SIZE+1]; u32 string_or = 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++) { u32 h0 = full_name_hash(buf+i, buf+i, j-i);
string_or |= h0; } /* i */ } /* j */
/* The OR of all the hash values should cover all the bits */ KUNIT_EXPECT_EQ_MSG(test, string_or, -1u, "OR of all string hash results = %#x != %#x", string_or, -1u);}
static void test_hash_or(struct kunit *test){ char buf[SIZE+1]; u32 hash_or[2][33] = { { 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 */ KUNIT_EXPECT_EQ_MSG(test, hashlen_len(hashlen), j-i, "hashlen_string(%d..%d) returned length %u, expected %d", i, j, hashlen_len(hashlen), j-i); /* Check that the hashes match */ KUNIT_EXPECT_EQ_MSG(test, hashlen_hash(hashlen), h0, "hashlen_string(%d..%d) = %08x != full_name_hash() = %08x", i, j, hashlen_hash(hashlen), h0);
h64 = h64 << 32 | h0; /* For use with hash_64 */ test_int_hash(test, h64, hash_or); } /* i */ } /* j */
KUNIT_EXPECT_EQ_MSG(test, hash_or[0][0], -1u, "OR of all __hash_32 results = %#x != %#x", hash_or[0][0], -1u);#ifdef HAVE_ARCH__HASH_32#if HAVE_ARCH__HASH_32 != 1 /* Test is pointless if results match */ KUNIT_EXPECT_EQ_MSG(test, hash_or[1][0], -1u, "OR of all __hash_32_generic results = %#x != %#x", hash_or[1][0], -1u);#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 */
KUNIT_EXPECT_EQ_MSG(test, hash_or[0][i], m, "OR of all hash_32(%d) results = %#x (%#x expected)", i, hash_or[0][i], m); KUNIT_EXPECT_EQ_MSG(test, hash_or[1][i], m, "OR of all hash_64(%d) results = %#x (%#x expected)", i, hash_or[1][i], m); }}
static struct kunit_case hash_test_cases[] __refdata = { KUNIT_CASE(test_string_or), KUNIT_CASE(test_hash_or), {}};
static struct kunit_suite hash_test_suite = { .name = "hash", .test_cases = hash_test_cases,};
kunit_test_suite(hash_test_suite);
MODULE_DESCRIPTION("Test cases for <linux/hash.h> and <linux/stringhash.h>");MODULE_LICENSE("GPL");