[PATCH] ACPI: bind workqueues to CPU 0 to avoid SMI corruption

Bjorn Helgaas
2009-07-29T21:54:26Z

On some machines, a software-initiated SMI causes corruption unless the
SMI runs on CPU 0. An SMI can be initiated by any AML, but typically it's
done in GPE-related methods that are run via workqueues, so we can avoid
the known corruption cases by binding the workqueues to CPU 0.

References:
http://bugzilla.kernel.org/show_bug.cgi?id=13751
https://bugs.launchpad.net/bugs/157171
https://bugs.launchpad.net/bugs/157691

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
---
drivers/acpi/osl.c | 25 +++++++++++++++++++++++++
1 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 7167071..5691f16 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -189,11 +189,36 @@ acpi_status __init acpi_os_initialize(void)
return AE_OK;
}

+static void bind_to_cpu0(struct work_struct *work)
+{
+ set_cpus_allowed(current, cpumask_of_cpu(0));
+ kfree(work);
+}
+
+static void bind_workqueue(struct workqueue_struct *wq)
+{
+ struct work_struct *work;
+
+ work = kzalloc(sizeof(struct work_struct), GFP_KERNEL);
+ INIT_WORK(work, bind_to_cpu0);
+ queue_work(wq, work);
+}
+
acpi_status acpi_os_initialize1(void)
{
+ /*
+ * On some machines, a software-initiated SMI causes corruption unless
+ * the SMI runs on CPU 0. An SMI can be initiated by any AML, but
+ * typically it's done in GPE-related methods that are run via
+ * workqueues, so we can avoid the known corruption cases by binding
+ * the workqueues to CPU 0.
+ */
kacpid_wq = create_singlethread_workqueue("kacpid");
+ bind_workqueue(kacpid_wq);
kacpi_notify_wq = create_singlethread_workqueue("kacpi_notify");
+ bind_workqueue(kacpi_notify_wq);
kacpi_hotplug_wq = create_singlethread_workqueue("kacpi_hotplug");
+ bind_workqueue(kacpi_hotplug_wq);
BUG_ON(!kacpid_wq);
BUG_ON(!kacpi_notify_wq);
BUG_ON(!kacpi_hotplug_wq);