Re: [PATCH V4 1/3] x86/ioapic: Support hot-removal of IOAPICs present during boot

[Rui Wang]

On Fri, Jun 24, 2016 1:35 AM Bjorn Helgaas wrote:
> On Thu, Jun 23, 2016 at 01:11:41PM +0800, Rui Wang wrote:
> > On Wed, June 22, 2016 11:15 PM Bjorn Helgaas wrote:
> > > [...]
> > > > @@ -1779,8 +1780,12 @@ void __init
> > > > pci_assign_unassigned_resources(void)
> > > >  {
> > > > struct pci_bus *root_bus;
> > > >
> > > > -   list_for_each_entry(root_bus, _root_buses, node)
> > > > +   list_for_each_entry(root_bus, _root_buses, node) {
> > > > pci_assign_unassigned_root_bus_resources(root_bus);
> > > > +#ifdef CONFIG_X86
> > > > +   acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
> > > > +#endif
> > >
> > > Doesn't this do the right thing even if you omit the #ifdefs, since
> > > you define a stub function below?
> > >
> >
> > No. Without the '#ifdef CONFIG_X86' it breaks MIPS arch. The stub
> > function is within 'ifdef CONFIG_ACPI'. On archs without ACPI it
> > doesn't compile due to 'undefined reference to acpi_ioapic_add'.
> 
> But this *could* be made to work by defining a stub for the non-
> CONFIG_ACPI case.  That's what we generally do to avoid ifdefs in the code.

That can be done. I'll make the change and do some cross-compiling tests first.

Thanks
Rui

Re: [PATCH V4 1/3] x86/ioapic: Support hot-removal of IOAPICs present during boot

[Rui Wang]

On Fri, Jun 24, 2016 1:35 AM Bjorn Helgaas wrote:
> On Thu, Jun 23, 2016 at 01:11:41PM +0800, Rui Wang wrote:
> > On Wed, June 22, 2016 11:15 PM Bjorn Helgaas wrote:
> > > [...]
> > > > @@ -1779,8 +1780,12 @@ void __init
> > > > pci_assign_unassigned_resources(void)
> > > >  {
> > > > struct pci_bus *root_bus;
> > > >
> > > > -   list_for_each_entry(root_bus, _root_buses, node)
> > > > +   list_for_each_entry(root_bus, _root_buses, node) {
> > > > pci_assign_unassigned_root_bus_resources(root_bus);
> > > > +#ifdef CONFIG_X86
> > > > +   acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
> > > > +#endif
> > >
> > > Doesn't this do the right thing even if you omit the #ifdefs, since
> > > you define a stub function below?
> > >
> >
> > No. Without the '#ifdef CONFIG_X86' it breaks MIPS arch. The stub
> > function is within 'ifdef CONFIG_ACPI'. On archs without ACPI it
> > doesn't compile due to 'undefined reference to acpi_ioapic_add'.
> 
> But this *could* be made to work by defining a stub for the non-
> CONFIG_ACPI case.  That's what we generally do to avoid ifdefs in the code.

That can be done. I'll make the change and do some cross-compiling tests first.

Thanks
Rui

Re: [PATCH V4 1/3] x86/ioapic: Support hot-removal of IOAPICs present during boot

[Bjorn Helgaas]

On Thu, Jun 23, 2016 at 01:11:41PM +0800,  wrote:
> From: Rui Wang 
> 
> On Wed, June 22, 2016 11:15 PM Bjorn Helgaas wrote:
> > [...]
> > > @@ -1779,8 +1780,12 @@ void __init
> > > pci_assign_unassigned_resources(void)
> > >  {
> > >   struct pci_bus *root_bus;
> > >
> > > - list_for_each_entry(root_bus, _root_buses, node)
> > > + list_for_each_entry(root_bus, _root_buses, node) {
> > >   pci_assign_unassigned_root_bus_resources(root_bus);
> > > +#ifdef CONFIG_X86
> > > + acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
> > > +#endif
> > 
> > Doesn't this do the right thing even if you omit the #ifdefs, since you
> > define a stub function below?
> > 
> 
> No. Without the '#ifdef CONFIG_X86' it breaks MIPS arch. The stub function is
> within 'ifdef CONFIG_ACPI'. On archs without ACPI it doesn't compile due to
> 'undefined reference to acpi_ioapic_add'.

But this *could* be made to work by defining a stub for the
non-CONFIG_ACPI case.  That's what we generally do to avoid ifdefs in
the code.

Bjorn

Re: [PATCH V4 1/3] x86/ioapic: Support hot-removal of IOAPICs present during boot

[Bjorn Helgaas]

On Thu, Jun 23, 2016 at 01:11:41PM +0800,  wrote:
> From: Rui Wang 
> 
> On Wed, June 22, 2016 11:15 PM Bjorn Helgaas wrote:
> > [...]
> > > @@ -1779,8 +1780,12 @@ void __init
> > > pci_assign_unassigned_resources(void)
> > >  {
> > >   struct pci_bus *root_bus;
> > >
> > > - list_for_each_entry(root_bus, _root_buses, node)
> > > + list_for_each_entry(root_bus, _root_buses, node) {
> > >   pci_assign_unassigned_root_bus_resources(root_bus);
> > > +#ifdef CONFIG_X86
> > > + acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
> > > +#endif
> > 
> > Doesn't this do the right thing even if you omit the #ifdefs, since you
> > define a stub function below?
> > 
> 
> No. Without the '#ifdef CONFIG_X86' it breaks MIPS arch. The stub function is
> within 'ifdef CONFIG_ACPI'. On archs without ACPI it doesn't compile due to
> 'undefined reference to acpi_ioapic_add'.

But this *could* be made to work by defining a stub for the
non-CONFIG_ACPI case.  That's what we generally do to avoid ifdefs in
the code.

Bjorn

Re: [PATCH V4 1/3] x86/ioapic: Support hot-removal of IOAPICs present during boot

From: Rui Wang 

On Wed, June 22, 2016 11:15 PM Bjorn Helgaas wrote:
> [...]
> > @@ -1779,8 +1780,12 @@ void __init
> > pci_assign_unassigned_resources(void)
> >  {
> > struct pci_bus *root_bus;
> >
> > -   list_for_each_entry(root_bus, _root_buses, node)
> > +   list_for_each_entry(root_bus, _root_buses, node) {
> > pci_assign_unassigned_root_bus_resources(root_bus);
> > +#ifdef CONFIG_X86
> > +   acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
> > +#endif
> 
> Doesn't this do the right thing even if you omit the #ifdefs, since you
> define a stub function below?
> 

No. Without the '#ifdef CONFIG_X86' it breaks MIPS arch. The stub function is
within 'ifdef CONFIG_ACPI'. On archs without ACPI it doesn't compile due to
'undefined reference to acpi_ioapic_add'.

Thanks
Rui

Re: [PATCH V4 1/3] x86/ioapic: Support hot-removal of IOAPICs present during boot

From: Rui Wang 

On Wed, June 22, 2016 11:15 PM Bjorn Helgaas wrote:
> [...]
> > @@ -1779,8 +1780,12 @@ void __init
> > pci_assign_unassigned_resources(void)
> >  {
> > struct pci_bus *root_bus;
> >
> > -   list_for_each_entry(root_bus, _root_buses, node)
> > +   list_for_each_entry(root_bus, _root_buses, node) {
> > pci_assign_unassigned_root_bus_resources(root_bus);
> > +#ifdef CONFIG_X86
> > +   acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
> > +#endif
> 
> Doesn't this do the right thing even if you omit the #ifdefs, since you
> define a stub function below?
> 

No. Without the '#ifdef CONFIG_X86' it breaks MIPS arch. The stub function is
within 'ifdef CONFIG_ACPI'. On archs without ACPI it doesn't compile due to
'undefined reference to acpi_ioapic_add'.

Thanks
Rui

Re: [PATCH V4 1/3] x86/ioapic: Support hot-removal of IOAPICs present during boot

[Bjorn Helgaas]

On Wed, Jun 22, 2016 at 03:40:19PM +0800, Rui Wang wrote:
> v4: Add comments explaining when to call acpi_ioapic_add().
> 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 
> ---
>  drivers/acpi/internal.h |  2 --
>  drivers/acpi/ioapic.c   |  7 ---
>  drivers/acpi/pci_root.c | 13 -
>  drivers/pci/setup-bus.c |  7 ++-
>  include/linux/acpi.h|  3 +++
>  5 files changed, 25 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
> index 27cc7fe..6d8e67e 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 **));
> +  root_handle, (void **));
>  
>   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..31e4440 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -614,7 +614,18 @@ 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);
> +
> + /*
> +  * 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);
>   }
>  
>   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 
>  #include 
>  #include 
> +#include 
>  #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, _root_buses, node)
> + list_for_each_entry(root_bus, _root_buses, node) {
>   pci_assign_unassigned_root_bus_resources(root_bus);
> +#ifdef CONFIG_X86
> + acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
> +#endif

Doesn't this do the right thing even if you omit the #ifdefs, since you
define a stub function below?

> + }
>  }
>  
>  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
> 

Re: [PATCH V4 1/3] x86/ioapic: Support hot-removal of IOAPICs present during boot

[Bjorn Helgaas]

On Wed, Jun 22, 2016 at 03:40:19PM +0800, Rui Wang wrote:
> v4: Add comments explaining when to call acpi_ioapic_add().
> 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 
> ---
>  drivers/acpi/internal.h |  2 --
>  drivers/acpi/ioapic.c   |  7 ---
>  drivers/acpi/pci_root.c | 13 -
>  drivers/pci/setup-bus.c |  7 ++-
>  include/linux/acpi.h|  3 +++
>  5 files changed, 25 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
> index 27cc7fe..6d8e67e 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 **));
> +  root_handle, (void **));
>  
>   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..31e4440 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -614,7 +614,18 @@ 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);
> +
> + /*
> +  * 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);
>   }
>  
>   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 
>  #include 
>  #include 
> +#include 
>  #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, _root_buses, node)
> + list_for_each_entry(root_bus, _root_buses, node) {
>   pci_assign_unassigned_root_bus_resources(root_bus);
> +#ifdef CONFIG_X86
> + acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
> +#endif

Doesn't this do the right thing even if you omit the #ifdefs, since you
define a stub function below?

> + }
>  }
>  
>  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
>