[PATCH v3 2/5] x86/ioapic: Support hot-removal of IOAPICs present during boot

Rui Wang
2016-08-10T04:18:30Z

IOAPICs present during system boot aren't added to ioapic_list,
thus are unable to be hot-removed. Fix it by calling
acpi_ioapic_add() during root bus enumeration.

Signed-off-by: Rui Wang <rui.y.wang@intel.com>
---
drivers/acpi/pci_root.c | 10 ++++++++++
drivers/pci/setup-bus.c | 5 ++++-
2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index b07eda1..bf601d4 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -614,6 +614,16 @@ static int acpi_pci_root_add(struct acpi_device *device,
if (hotadd) {
pcibios_resource_survey_bus(root->bus);
pci_assign_unassigned_root_bus_resources(root->bus);
+ /*
+ * This is only called for the hotadd case. For the boot-time
+ * case, we need to wait until after PCI initialization in
+ * order to deal with IOAPICs mapped in on a PCI BAR.
+ *
+ * This is currently x86-specific, because acpi_ioapic_add()
+ * is an empty function without CONFIG_ACPI_HOTPLUG_IOAPIC.
+ * And CONFIG_ACPI_HOTPLUG_IOAPIC depends on CONFIG_X86_IO_APIC
+ * (see drivers/acpi/Kconfig).
+ */
acpi_ioapic_add(root->device->handle);
}

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index c74059e..ec538d3 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -25,6 +25,7 @@
#include <linux/ioport.h>
#include <linux/cache.h>
#include <linux/slab.h>
+#include <linux/acpi.h>
#include "pci.h"

unsigned int pci_flags;
@@ -1852,8 +1853,10 @@ void __init pci_assign_unassigned_resources(void)
{
struct pci_bus *root_bus;

- list_for_each_entry(root_bus, &pci_root_buses, node)
+ list_for_each_entry(root_bus, &pci_root_buses, node) {
pci_assign_unassigned_root_bus_resources(root_bus);
+ acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
+ }
}

void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
--
1.8.3.1