On Wed, Jun 08, 2016 at 05:32:44PM +0800, Rui Wang wrote:
> v3: Previous versions break mips. This version fixes it.
>
> 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@xxxxxxxxx>
> ---
> drivers/acpi/internal.h | 2 --
> drivers/acpi/ioapic.c | 7 ++++---
> drivers/acpi/pci_root.c | 2 +-
> drivers/pci/setup-bus.c | 7 ++++++-
> include/linux/acpi.h | 3 +++
> 5 files changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
> index 9bb0773..bb567a7 100644
> --- a/drivers/acpi/internal.h
> +++ b/drivers/acpi/internal.h
> @@ -40,10 +40,8 @@ int acpi_sysfs_init(void);
> void acpi_container_init(void);
> void acpi_memory_hotplug_init(void);
> #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
> -int acpi_ioapic_add(struct acpi_pci_root *root);
> int acpi_ioapic_remove(struct acpi_pci_root *root);
> #else
> -static inline int acpi_ioapic_add(struct acpi_pci_root *root) { return 0; }
> static inline int acpi_ioapic_remove(struct acpi_pci_root *root) { return 0; }
> #endif
> #ifdef CONFIG_ACPI_DOCK
> diff --git a/drivers/acpi/ioapic.c b/drivers/acpi/ioapic.c
> index ccdc8db..0f272e2 100644
> --- a/drivers/acpi/ioapic.c
> +++ b/drivers/acpi/ioapic.c
> @@ -189,16 +189,17 @@ exit:
> return AE_OK;
> }
>
> -int acpi_ioapic_add(struct acpi_pci_root *root)
> +int acpi_ioapic_add(acpi_handle root_handle)
> {
> acpi_status status, retval = AE_OK;
>
> - status = acpi_walk_namespace(ACPI_TYPE_DEVICE, root->device->handle,
> + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, root_handle,
> UINT_MAX, handle_ioapic_add, NULL,
> - root->device->handle, (void **)&retval);
> + root_handle, (void **)&retval);
>
> return ACPI_SUCCESS(status) && ACPI_SUCCESS(retval) ? 0 : -ENODEV;
> }
> +EXPORT_SYMBOL_GPL(acpi_ioapic_add);
>
> int acpi_ioapic_remove(struct acpi_pci_root *root)
> {
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index ae3fe4e..53f5965 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -614,7 +614,7 @@ 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);
> - acpi_ioapic_add(root);
> + acpi_ioapic_add(root->device->handle);
> }
>
> pci_lock_rescan_remove();
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 55641a3..0658921 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;
> @@ -1779,8 +1780,12 @@ 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);
> +#ifdef CONFIG_X86
> + acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
> +#endif
This seems like a strange place to call acpi_ioapic_add(). Your
object is to call acpi_ioapic_add() during root bus enumeration.
I assume we *can't* call acpi_ioapic_add() from acpi_pci_root_add() at
boot time, for some reason you'll explain. But is there a reason we
have to call it from pci_assign_unassigned_resources() (where it
requires an ifdef) instead of from pcibios_assign_resources(), which
is already x86-specific?
In acpi_pci_root_add(), we have this:
acpi_pci_root_add(...)
{
...
if (hotadd)
acpi_ioapic_add(root);
So the obvious question is why don't we just remove the "if (hotadd)"
and call acpi_ioapic_add() always.
I'm sure the reason is some ordering problem, but we need a comment in
acpi_pci_root_add() about why the obvious solution doesn't work.
> + }
> }
>
> void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 288fac5..3ed22df 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -262,6 +262,9 @@ int acpi_unmap_cpu(int cpu);
>
> #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
> int acpi_get_ioapic_id(acpi_handle handle, u32 gsi_base, u64 *phys_addr);
> +int acpi_ioapic_add(acpi_handle root);
> +#else
> +static inline int acpi_ioapic_add(acpi_handle root) { return 0; }
> #endif
>
> int acpi_register_ioapic(acpi_handle handle, u64 phys_addr, u32 gsi_base);
> --
> 1.8.3.1
>
> --
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