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authorHans Petter Selasky <hselasky@FreeBSD.org>2016-12-19 10:00:56 +0000
committerHans Petter Selasky <hselasky@FreeBSD.org>2016-12-19 10:00:56 +0000
commit16bcbf27a74b6e137bb50cbc47a3b9bd44727044 (patch)
tree113a1da15b8014bfdf44e72789882492605dba29
parentebd60d5f50f0b9196eebf9113e734682b18d561f (diff)
downloadsrc-16bcbf27a74b6e137bb50cbc47a3b9bd44727044.tar.gz
src-16bcbf27a74b6e137bb50cbc47a3b9bd44727044.zip
MFC r309400:
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
Notes
Notes: svn path=/stable/8/; revision=310256
-rw-r--r--sys/dev/acpica/acpi_ec.c40
1 files changed, 31 insertions, 9 deletions
diff --git a/sys/dev/acpica/acpi_ec.c b/sys/dev/acpica/acpi_ec.c
index b505af307ad4..d7d7f25f33b2 100644
--- a/sys/dev/acpica/acpi_ec.c
+++ b/sys/dev/acpica/acpi_ec.c
@@ -618,16 +618,14 @@ EcCheckStatus(struct acpi_ec_softc *sc, const char *msg, EC_EVENT event)
}
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);
@@ -654,7 +652,6 @@ EcGpeQueryHandler(void *Context)
else
break;
}
- sc->ec_sci_pend = FALSE;
if (ACPI_FAILURE(Status)) {
EcUnlock(sc);
device_printf(sc->ec_dev, "GPE query failed: %s\n",
@@ -685,6 +682,29 @@ 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.
@@ -713,13 +733,14 @@ EcGpeHandler(void *Context)
* 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 (0);
}
@@ -766,7 +787,8 @@ EcSpaceHandler(UINT32 Function, ACPI_PHYSICAL_ADDRESS Address, UINT32 Width,
* 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);
}