| /* |
| * 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. */ |
| #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"); |