From 70a640c0efa7667453c3911b13335304ce46ad8b Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 26 Apr 2023 15:35:45 +0200 Subject: [PATCH 1/4] regmap: REGMAP_KUNIT should not select REGMAP Enabling a (modular) test should not silently enable additional kernel functionality, as that may increase the attack vector of a product. Fix this by: 1. making REGMAP visible if CONFIG_KUNIT_ALL_TESTS is enabled, 2. making REGMAP_KUNIT depend on REGMAP instead of selecting it. After this, one can safely enable CONFIG_KUNIT_ALL_TESTS=m to build modules for all appropriate tests for ones system, without pulling in extra unwanted functionality, while still allowing a tester to manually enable REGMAP and its test suite on a system where REGMAP is not enabled by default. Fixes: 2238959b6ad27040 ("regmap: Add some basic kunit tests") Signed-off-by: Geert Uytterhoeven Date: Wed, 17 May 2023 10:20:11 -0500 Subject: [PATCH 2/4] regmap: Account for register length when chunking Currently, when regmap_raw_write() splits the data, it uses the max_raw_write value defined for the bus. For any bus that includes the target register address in the max_raw_write value, the chunked transmission will always exceed the maximum transmission length. To avoid this problem, subtract the length of the register and the padding from the maximum transmission. Signed-off-by: Jim Wylder max_raw_write - map->format.reg_bytes - + map->format.pad_bytes; int ret, i; if (!val_count) @@ -2089,8 +2091,8 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg, if (map->use_single_write) chunk_regs = 1; - else if (map->max_raw_write && val_len > map->max_raw_write) - chunk_regs = map->max_raw_write / val_bytes; + else if (map->max_raw_write && val_len > max_data) + chunk_regs = max_data / val_bytes; chunk_count = val_count / chunk_regs; chunk_bytes = chunk_regs * val_bytes; From 95856d1f3c223c015780fffb8373a827fc4efd2e Mon Sep 17 00:00:00 2001 From: Srinivas Kandagatla Date: Tue, 23 May 2023 16:47:47 +0100 Subject: [PATCH 3/4] regmap: sdw: check for invalid multi-register writes config SoundWire code as it is only supports Bulk register writes and it does not support multi-register writes. Any drivers that set can_multi_write and use regmap_multi_reg_write() will easily endup with programming the hardware incorrectly without any errors. So, add this check in bus code to be able to validate the drivers config. Fixes: 522272047dc6 ("regmap: sdw: Remove 8-bit value size restriction") Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20230523154747.5429-1-srinivas.kandagatla@linaro.org Signed-off-by: Mark Brown --- drivers/base/regmap/regmap-sdw.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/base/regmap/regmap-sdw.c b/drivers/base/regmap/regmap-sdw.c index 09899ae99fc1..159c0b740b00 100644 --- a/drivers/base/regmap/regmap-sdw.c +++ b/drivers/base/regmap/regmap-sdw.c @@ -59,6 +59,10 @@ static int regmap_sdw_config_check(const struct regmap_config *config) if (config->pad_bits != 0) return -ENOTSUPP; + /* Only bulk writes are supported not multi-register writes */ + if (config->can_multi_write) + return -ENOTSUPP; + return 0; } From 0cc6578048e0980d254aee345130cced4912f723 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Tue, 23 May 2023 23:18:19 +0100 Subject: [PATCH 4/4] regmap: maple: Drop the RCU read lock while syncing registers Unfortunately the maple tree requires us to explicitly lock it so we need to take the RCU read lock while iterating. When syncing this means that we end up trying to write out register values while holding the RCU read lock which triggers lockdep issues since that is an atomic context but most buses can't be used in atomic context. Pause the iteration and drop the lock for each register we check to avoid this. Reported-by: Pierre-Louis Bossart Tested-by: Pierre-Louis Bossart Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20230523-regcache-maple-sync-lock-v1-1-530e4d68dfab@kernel.org Signed-off-by: Mark Brown --- drivers/base/regmap/regcache-maple.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/base/regmap/regcache-maple.c b/drivers/base/regmap/regcache-maple.c index 9b1b559107ef..c2e3a0f6c218 100644 --- a/drivers/base/regmap/regcache-maple.c +++ b/drivers/base/regmap/regcache-maple.c @@ -203,15 +203,18 @@ static int regcache_maple_sync(struct regmap *map, unsigned int min, mas_for_each(&mas, entry, max) { for (r = max(mas.index, lmin); r <= min(mas.last, lmax); r++) { + mas_pause(&mas); + rcu_read_unlock(); ret = regcache_sync_val(map, r, entry[r - mas.index]); if (ret != 0) goto out; + rcu_read_lock(); } } -out: rcu_read_unlock(); +out: map->cache_bypass = false; return ret;