Unverified Commit 42afe80c authored by Mark Brown's avatar Mark Brown
Browse files

regmap: Specifically test writing 0 as a value to sparse caches 



Since 0 can look a lot like a NULL pointer when used in a cache some clever
data structures might potentially introduce bugs specific to handling it.
Add some explicit testing of storing 0 as a value in a sparse cache, at the
minute there are no issues and this will stop any appearing in the future.

Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Link: https://patch.msgid.link/20240924-regcache-zero-value-v1-1-8a1224214b52@kernel.org


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 21e9a1dd

drivers/base/regmap/regmap-kunit.c

+43 −0
Original line number Diff line number Diff line
@@ -1499,6 +1499,48 @@ static void cache_present(struct kunit *test) 
		KUNIT_ASSERT_TRUE(test, regcache_reg_cached(map, param->from_reg + i));

}



static void cache_write_zero(struct kunit *test)

{

	const struct regmap_test_param *param = test->param_value;

	struct regmap *map;

	struct regmap_config config;

	struct regmap_ram_data *data;

	unsigned int val;

	int i;



	config = test_regmap_config;



	map = gen_regmap(test, &config, &data);

	KUNIT_ASSERT_FALSE(test, IS_ERR(map));

	if (IS_ERR(map))

		return;



	for (i = 0; i < BLOCK_TEST_SIZE; i++)

		data->read[param->from_reg + i] = false;



	/* No defaults so no registers cached. */

	for (i = 0; i < BLOCK_TEST_SIZE; i++)

		KUNIT_ASSERT_FALSE(test, regcache_reg_cached(map, param->from_reg + i));



	/* We didn't trigger any reads */

	for (i = 0; i < BLOCK_TEST_SIZE; i++)

		KUNIT_ASSERT_FALSE(test, data->read[param->from_reg + i]);



	/* Write a zero value */

	KUNIT_EXPECT_EQ(test, 0, regmap_write(map, 1, 0));



	/* Read that zero value back */

	KUNIT_EXPECT_EQ(test, 0, regmap_read(map, 1, &val));

	KUNIT_EXPECT_EQ(test, 0, val);



	/* From the cache? */

	KUNIT_ASSERT_TRUE(test, regcache_reg_cached(map, 1));



	/* Try to throw it away */

	KUNIT_EXPECT_EQ(test, 0, regcache_drop_region(map, 1, 1));

	KUNIT_ASSERT_FALSE(test, regcache_reg_cached(map, 1));

}



/* Check that caching the window register works with sync */

static void cache_range_window_reg(struct kunit *test)

{
@@ -2012,6 +2054,7 @@ static struct kunit_case regmap_test_cases[] = { 
	KUNIT_CASE_PARAM(cache_drop_all_and_sync_no_defaults, sparse_cache_types_gen_params),

	KUNIT_CASE_PARAM(cache_drop_all_and_sync_has_defaults, sparse_cache_types_gen_params),

	KUNIT_CASE_PARAM(cache_present, sparse_cache_types_gen_params),

	KUNIT_CASE_PARAM(cache_write_zero, sparse_cache_types_gen_params),

	KUNIT_CASE_PARAM(cache_range_window_reg, real_cache_types_only_gen_params),



	KUNIT_CASE_PARAM(raw_read_defaults_single, raw_test_types_gen_params),