kernel/git/stable/linux.git/drivers/acpi/ec.c, branch linux-4.4.y

ACPI: EC: Reference count query handlers under lock

2020-10-01T09:11:51+00:00

[ Upstream commit 3df663a147fe077a6ee8444ec626738946e65547 ] There is a race condition in acpi_ec_get_query_handler() theoretically allowing query handlers to go away before refernce counting them. In order to avoid it, call kref_get() on query handlers under ec->mutex. Also simplify the code a bit while at it. Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

ACPI / EC: Work around method reentrancy limit in ACPICA for _Qxx

2016-08-20T16:09:27+00:00

commit e1191bd4f62d9086a1a47adc286e7fcffc1fa55c upstream. A regression is caused by the following commit: Commit: 02b771b64b73226052d6e731a0987db3b47281e9 Subject: ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations In this commit, using system workqueue causes that the maximum parallel executions of _Qxx can exceed 255. This violates the method reentrancy limit in ACPICA and generates the following error log: ACPI Error: Method reached maximum reentrancy limit (255) (20150818/dsmethod-341) This patch creates a seperate workqueue and limits the number of parallel _Qxx evaluations down to a configurable value (can be tuned against number of online CPUs). Since EC events are handled after driver probe, we can create the workqueue in acpi_ec_init(). Fixes: 02b771b64b73 (ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations) Link: https://bugzilla.kernel.org/show_bug.cgi?id=135691 Reported-and-tested-by: Helen Buus Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

ACPI-EC: Drop unnecessary check made before calling acpi_ec_delete_query()

2015-11-16T22:29:44+00:00

The acpi_ec_delete_query() function tests whether its argument is NULL and then returns immediately. Thus the test around the call is not needed. This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring [ rjw: Subject ] Signed-off-by: Rafael J. Wysocki

ACPI / EC: Fix a race issue in acpi_ec_guard_event()

2015-09-25T23:46:25+00:00

In acpi_ec_guard_event(), EC transaction state machine variables should be checked with the EC spinlock locked. The bug doesn't trigger any real issue now because this bug can only occur when the ec_event_clearing=event mode is applied while there is no user currently using this mode. Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki

ACPI / EC: Fix query handler related issues

2015-09-25T23:46:24+00:00

1. acpi_ec_remove_query_handlers() This patch refines the query handler removal logic implemented in acpi_ec_remove_query_handler(), making it to invoke new acpi_ec_remove_query_handlers() API, and ensuring all other removal code paths to invoke the new API to honor the reference count of the query handlers. 2. acpi_ec_get_query_handler_by_value() This patch also refines the query handler search logic originally implemented in acpi_ec_query(), collecting it into acpi_ec_get_query_handler_by_value(). And since schedule_work() can ensure the serilization of acpi_ec_event_handler(), we needn't put the mutex_lock() around schedule_work(). Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki

ACPI / EC: Fix a memory leak issue in acpi_ec_query()

2015-09-25T23:44:59+00:00

When query handler is not found, "result" is actually stil 0, and "struct acpi_ec_query" is not NULL, so the deletion code of "struct acpi_ec_query" at the end of the function cannot be invoked. As a consequence, memory leak can be observed. The issue is introduced by this commit: Commit: 02b771b64b73226052d6e731a0987db3b47281e9 Subject: ACPI / EC: Fix an issue caused by the serialized _Qxx This patch fixes such memory leakage. Fixes: 02b771b64b73 (ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations) Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki

Merge branches 'acpi-pci', 'acpi-soc', 'acpi-ec' and 'acpi-osl'

2015-09-01T01:41:19+00:00

* acpi-pci: ACPI, PCI: Penalize legacy IRQ used by ACPI SCI * acpi-soc: ACPI / LPSS: Ignore 10ms delay for Braswell * acpi-ec: ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations * acpi-osl: ACPI / osl: replace custom implementation of readq / writeq

ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations

2015-08-25T01:19:32+00:00

It is proven that Windows evaluates _Qxx handlers in a parallel way. This patch follows this fact, splits _Qxx evaluations from the NOTIFY queue to form a separate queue, so that _Qxx evaluations can be queued up on different CPUs rather than being queued up on a CPU0 bound queue. Event handling related callbacks are also renamed and sorted in this patch. Link: https://bugzilla.kernel.org/show_bug.cgi?id=94411 Reported-and-tested-by: Gabriele Mazzotta Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki

ACPI: Remove FSF mailing addresses

2015-07-08T00:27:32+00:00

There is no need to carry potentially outdated Free Software Foundation mailing address in file headers since the COPYING file includes it. Signed-off-by: Jarkko Nikula Signed-off-by: Rafael J. Wysocki

ACPI / EC: Fix a code coverity issue when QR_EC transactions are failed.

2015-06-15T12:35:59+00:00

When the QR_EC transaction fails, the EC_FLAGS_QUERY_PENDING flag prevents the event handling work queue from being scheduled again. Though there shouldn't be failed QR_EC transactions, and this gap was efficiently used for catching and learning the SCI_EVT clearing timing compliance issues, we need to fix this as we are not fully compatible with all platforms/Windows to handle SCI_EVT clearing timing correctly. Fixing this gives the EC driver the chances to recover from a state machine failure. So this patch fixes this issue. When nr_pending_queries drops to 0, it clears EC_FLAGS_QUERY_PENDING at the proper position for different modes in order to ensure that the SCI_EVT handling can proceed. In order to be clearer for future ec_event_clearing modes, all checks in this patch are written in the inclusive style, not the exclusive style. Cc: 3.16+ # 3.16+ Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki