linux/lib/test_hash.c

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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, &params);
#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);
hash.h: remove unused define directive Patch series "test_hash.c: refactor into KUnit", v3. We refactored the lib/test_hash.c file into KUnit as part of the student group LKCAMP [1] introductory hackathon for kernel development. This test was pointed to our group by Daniel Latypov [2], so its full conversion into a pure KUnit test was our goal in this patch series, but we ran into many problems relating to it not being split as unit tests, which complicated matters a bit, as the reasoning behind the original tests is quite cryptic for those unfamiliar with hash implementations. Some interesting developments we'd like to highlight are: - In patch 1/5 we noticed that there was an unused define directive that could be removed. - In patch 4/5 we noticed how stringhash and hash tests are all under the lib/test_hash.c file, which might cause some confusion, and we also broke those kernel config entries up. Overall KUnit developments have been made in the other patches in this series: In patches 2/5, 3/5 and 5/5 we refactored the lib/test_hash.c file so as to make it more compatible with the KUnit style, whilst preserving the original idea of the maintainer who designed it (i.e. George Spelvin), which might be undesirable for unit tests, but we assume it is enough for a first patch. This patch (of 5): Currently, there exist hash_32() and __hash_32() functions, which were introduced in a patch [1] targeting architecture specific optimizations. These functions can be overridden on a per-architecture basis to achieve such optimizations. They must set their corresponding define directive (HAVE_ARCH_HASH_32 and HAVE_ARCH__HASH_32, respectively) so that header files can deal with these overrides properly. As the supported 32-bit architectures that have their own hash function implementation (i.e. m68k, Microblaze, H8/300, pa-risc) have only been making use of the (more general) __hash_32() function (which only lacks a right shift operation when compared to the hash_32() function), remove the define directive corresponding to the arch-specific hash_32() implementation. [1] https://lore.kernel.org/lkml/20160525073311.5600.qmail@ns.sciencehorizons.net/ [akpm@linux-foundation.org: hash_32_generic() becomes hash_32()] Link: https://lkml.kernel.org/r/20211208183711.390454-1-isabbasso@riseup.net Link: https://lkml.kernel.org/r/20211208183711.390454-2-isabbasso@riseup.net Reviewed-by: David Gow <davidgow@google.com> Tested-by: David Gow <davidgow@google.com> Co-developed-by: Augusto Durães Camargo <augusto.duraes33@gmail.com> Signed-off-by: Augusto Durães Camargo <augusto.duraes33@gmail.com> Co-developed-by: Enzo Ferreira <ferreiraenzoa@gmail.com> Signed-off-by: Enzo Ferreira <ferreiraenzoa@gmail.com> Signed-off-by: Isabella Basso <isabbasso@riseup.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Brendan Higgins <brendanhiggins@google.com> Cc: Daniel Latypov <dlatypov@google.com> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com> Cc: kernel test robot <lkp@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-20 02:09:02 +00:00
/* 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, &params, &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);
KUnit: add missing MODULE_DESCRIPTION() macros for lib/test_*.ko make allmodconfig && make W=1 C=1 reports for lib/test_*.ko: WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_hexdump.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_dhry.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_firmware.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_sysctl.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_hash.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_ida.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_list_sort.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_min_heap.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_module.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_sort.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_static_keys.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_static_key_base.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_memcat_p.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_blackhole_dev.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_meminit.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_free_pages.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_kprobes.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_ref_tracker.o WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_bits.o Add the missing invocations of the MODULE_DESCRIPTION() macro. Link: https://lkml.kernel.org/r/20240619-md-lib-test-v2-1-301e30eeba1e@quicinc.com Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com> Reviewed-by: Kees Cook <kees@kernel.org> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-19 20:59:15 +00:00
MODULE_DESCRIPTION("Test cases for <linux/hash.h> and <linux/stringhash.h>");
MODULE_LICENSE("GPL");