/* * Test cases for and * 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 #include #include #include #include #include /* 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