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- // 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_32
- static void
- test_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_64
- static void
- test_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 void
- test_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_LICENSE("GPL");
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