#define GOLDEN_RATIO_32 0x61C88647
#define GOLDEN_RATIO_64 0x61C8864680B583EBull
+#ifdef CONFIG_HAVE_ARCH_HASH
+/* This header may use the GOLDEN_RATIO_xx constants */
+#include <asm/hash.h>
+#endif
-static inline u32 __hash_32(u32 val)
+/*
+ * The _generic versions exist only so lib/test_hash.c can compare
+ * the arch-optimized versions with the generic.
+ *
+ * Note that if you change these, any <asm/hash.h> that aren't updated
+ * to match need to have their HAVE_ARCH_* define values updated so the
+ * self-test will not false-positive.
+ */
+#ifndef HAVE_ARCH__HASH_32
+#define __hash_32 __hash_32_generic
+#endif
+static inline u32 __hash_32_generic(u32 val)
{
return val * GOLDEN_RATIO_32;
}
-static inline u32 hash_32(u32 val, unsigned int bits)
+#ifndef HAVE_ARCH_HASH_32
+#define hash_32 hash_32_generic
+#endif
+static inline u32 hash_32_generic(u32 val, unsigned int bits)
{
/* High bits are more random, so use them. */
return __hash_32(val) >> (32 - bits);
}
-static __always_inline u32 hash_64(u64 val, unsigned int bits)
+#ifndef HAVE_ARCH_HASH_64
+#define hash_64 hash_64_generic
+#endif
+static __always_inline u32 hash_64_generic(u64 val, unsigned int bits)
{
#if BITS_PER_LONG == 64
/* 64x64-bit multiply is efficient on all 64-bit processors */
--- /dev/null
+/*
+ * 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);
+ u32 h0 = full_name_hash(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");
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