svn commit: r309400 - head/sys/dev/acpica
Oliver Pinter
oliver.pinter at hardenedbsd.org
Sat Dec 3 20:12:58 UTC 2016
On Fri, Dec 2, 2016 at 9:21 AM, Hans Petter Selasky
<hselasky at freebsd.org> wrote:
> Author: hselasky
> Date: Fri Dec 2 08:21:08 2016
> New Revision: 309400
> URL: https://svnweb.freebsd.org/changeset/base/309400
>
> Log:
> Fix for endless recursion in the ACPI GPE handler during boot.
>
> When handling a GPE ACPI interrupt object the EcSpaceHandler()
> function can be called which checks the EC_EVENT_SCI bit and then
> recurse on the EcGpeQueryHandler() function. If there are multiple GPE
> events pending the EC_EVENT_SCI bit will be set at the next call to
> EcSpaceHandler() causing it to recurse again via the
> EcGpeQueryHandler() function. This leads to a slow never ending
> recursion during boot which prevents proper system startup, because
> the EC_EVENT_SCI bit never gets cleared in this scenario.
>
> The behaviour is reproducible with the ALASKA AMI in combination with
> a newer Skylake based mainboard in the following way:
>
> Enter BIOS and adjust the clock one hour forward. Save and exit the
> BIOS. System fails to boot due to the above mentioned bug in
> EcGpeQueryHandler() which was observed recursing multiple times.
>
> This patch adds a simple recursion guard to the EcGpeQueryHandler()
> function and also also adds logic to detect if new GPE events occurred
> during the execution of EcGpeQueryHandler() and then loop on this
> function instead of recursing.
>
> Reviewed by: jhb
> MFC after: 2 weeks
>
> Modified:
> head/sys/dev/acpica/acpi_ec.c
I have similar error since the latest BIOS update on my gigabyte
H170N-Wifi board. The curiosity of the BIOS update was after upgrading
to this version, there are no possibility to rollback to older
version.
The other weird thing, is that MFCing back this patch does not help. I
get stucked lock in acmtx mutex, as you
could see from the attached log. The other interesting is the ACPI
error at boot time:
[1] ACPI Error: Mutex [0x0] is not acquired, cannot release
(20160527/utmutex-386)
[1] ACPI Error: Could not release AML Interpreter mutex (20160527/exutils-147)
[1] ACPI Error: Mutex [0x0] is not acquired, cannot release
(20160527/utmutex-386)
[1] ACPI Error: Could not release AML Interpreter mutex (20160527/exutils-147)
[1] cpu1: <ACPI CPU> on acpi0
[1] ACPI Error: Mutex [0x0] is not acquired, cannot release
(20160527/utmutex-386)
[1] ACPI Error: Could not release AML Interpreter mutex (20160527/exutils-147)
[1] ACPI Error: Mutex [0x0] is not acquired, cannot release
(20160527/utmutex-386)
[1] ACPI Error: Could not release AML Interpreter mutex (20160527/exutils-147)
(This error is on 10-STABLE.)
>
> Modified: head/sys/dev/acpica/acpi_ec.c
> ==============================================================================
> --- head/sys/dev/acpica/acpi_ec.c Fri Dec 2 08:15:52 2016 (r309399)
> +++ head/sys/dev/acpica/acpi_ec.c Fri Dec 2 08:21:08 2016 (r309400)
> @@ -613,16 +613,14 @@ EcCheckStatus(struct acpi_ec_softc *sc,
> }
>
> static void
> -EcGpeQueryHandler(void *Context)
> +EcGpeQueryHandlerSub(struct acpi_ec_softc *sc)
> {
> - struct acpi_ec_softc *sc = (struct acpi_ec_softc *)Context;
> UINT8 Data;
> ACPI_STATUS Status;
> int retry;
> char qxx[5];
>
> ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
> - KASSERT(Context != NULL, ("EcGpeQueryHandler called with NULL"));
>
> /* Serialize user access with EcSpaceHandler(). */
> Status = EcLock(sc);
> @@ -647,7 +645,6 @@ EcGpeQueryHandler(void *Context)
> EC_EVENT_INPUT_BUFFER_EMPTY)))
> break;
> }
> - sc->ec_sci_pend = FALSE;
> if (ACPI_FAILURE(Status)) {
> EcUnlock(sc);
> device_printf(sc->ec_dev, "GPE query failed: %s\n",
> @@ -678,6 +675,29 @@ EcGpeQueryHandler(void *Context)
> }
> }
>
> +static void
> +EcGpeQueryHandler(void *Context)
> +{
> + struct acpi_ec_softc *sc = (struct acpi_ec_softc *)Context;
> + int pending;
> +
> + KASSERT(Context != NULL, ("EcGpeQueryHandler called with NULL"));
> +
> + do {
> + /* Read the current pending count */
> + pending = atomic_load_acq_int(&sc->ec_sci_pend);
> +
> + /* Call GPE handler function */
> + EcGpeQueryHandlerSub(sc);
> +
> + /*
> + * Try to reset the pending count to zero. If this fails we
> + * know another GPE event has occurred while handling the
> + * current GPE event and need to loop.
> + */
> + } while (!atomic_cmpset_int(&sc->ec_sci_pend, pending, 0));
> +}
> +
> /*
> * The GPE handler is called when IBE/OBF or SCI events occur. We are
> * called from an unknown lock context.
> @@ -706,13 +726,14 @@ EcGpeHandler(ACPI_HANDLE GpeDevice, UINT
> * It will run the query and _Qxx method later, under the lock.
> */
> EcStatus = EC_GET_CSR(sc);
> - if ((EcStatus & EC_EVENT_SCI) && !sc->ec_sci_pend) {
> + if ((EcStatus & EC_EVENT_SCI) &&
> + atomic_fetchadd_int(&sc->ec_sci_pend, 1) == 0) {
> CTR0(KTR_ACPI, "ec gpe queueing query handler");
> Status = AcpiOsExecute(OSL_GPE_HANDLER, EcGpeQueryHandler, Context);
> - if (ACPI_SUCCESS(Status))
> - sc->ec_sci_pend = TRUE;
> - else
> + if (ACPI_FAILURE(Status)) {
> printf("EcGpeHandler: queuing GPE query handler failed\n");
> + atomic_store_rel_int(&sc->ec_sci_pend, 0);
> + }
> }
> return (ACPI_REENABLE_GPE);
> }
> @@ -759,7 +780,8 @@ EcSpaceHandler(UINT32 Function, ACPI_PHY
> * we call it directly here since our thread taskq is not active yet.
> */
> if (cold || rebooting || sc->ec_suspending) {
> - if ((EC_GET_CSR(sc) & EC_EVENT_SCI)) {
> + if ((EC_GET_CSR(sc) & EC_EVENT_SCI) &&
> + atomic_fetchadd_int(&sc->ec_sci_pend, 1) == 0) {
> CTR0(KTR_ACPI, "ec running gpe handler directly");
> EcGpeQueryHandler(sc);
> }
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