[01/13] x86/acpi: Extract ACPI MADT wakeup code into a separate file
Commit Message
In order to prepare for the expansion of support for the ACPI MADT
wakeup method, the relevant code has been moved into a separate file.
A new configuration option has been introduced to clearly indicate
dependencies without the use of ifdefs.
There have been no functional changes.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
arch/x86/Kconfig | 7 +++
arch/x86/include/asm/acpi.h | 5 ++
arch/x86/kernel/acpi/Makefile | 11 ++--
arch/x86/kernel/acpi/boot.c | 86 +-----------------------------
arch/x86/kernel/acpi/madt_wakeup.c | 80 +++++++++++++++++++++++++++
5 files changed, 99 insertions(+), 90 deletions(-)
create mode 100644 arch/x86/kernel/acpi/madt_wakeup.c
Comments
On Thu, 2023-10-05 at 16:13 +0300, Kirill A. Shutemov wrote:
> In order to prepare for the expansion of support for the ACPI MADT
> wakeup method, the relevant code has been moved into a separate file.
> A new configuration option has been introduced to clearly indicate
> dependencies without the use of ifdefs.
Use imperative mood?
- Move the relevant code into ...
- Introduce a new configuration option to ...
>
> There have been no functional changes.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
> arch/x86/Kconfig | 7 +++
> arch/x86/include/asm/acpi.h | 5 ++
> arch/x86/kernel/acpi/Makefile | 11 ++--
> arch/x86/kernel/acpi/boot.c | 86 +-----------------------------
> arch/x86/kernel/acpi/madt_wakeup.c | 80 +++++++++++++++++++++++++++
> 5 files changed, 99 insertions(+), 90 deletions(-)
> create mode 100644 arch/x86/kernel/acpi/madt_wakeup.c
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 3154dbc49cf5..7368d254d01f 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1108,6 +1108,13 @@ config X86_LOCAL_APIC
> depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
> select IRQ_DOMAIN_HIERARCHY
>
> +config X86_ACPI_MADT_WAKEUP
> + def_bool y
> + depends on X86_64
> + depends on ACPI
> + depends on SMP
> + depends on X86_LOCAL_APIC
> +
> config X86_IO_APIC
> def_bool y
> depends on X86_LOCAL_APIC || X86_UP_IOAPIC
> diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
> index c8a7fc23f63c..b536b5a6a57b 100644
> --- a/arch/x86/include/asm/acpi.h
> +++ b/arch/x86/include/asm/acpi.h
> @@ -73,6 +73,11 @@ static inline bool acpi_skip_set_wakeup_address(void)
>
> #define acpi_skip_set_wakeup_address acpi_skip_set_wakeup_address
>
> +union acpi_subtable_headers;
> +
> +int __init acpi_parse_mp_wake(union acpi_subtable_headers *header,
> + const unsigned long end);
> +
> /*
> * Check if the CPU can handle C2 and deeper
> */
> diff --git a/arch/x86/kernel/acpi/Makefile b/arch/x86/kernel/acpi/Makefile
> index fc17b3f136fe..8c7329c88a75 100644
> --- a/arch/x86/kernel/acpi/Makefile
> +++ b/arch/x86/kernel/acpi/Makefile
> @@ -1,11 +1,12 @@
> # SPDX-License-Identifier: GPL-2.0
>
> -obj-$(CONFIG_ACPI) += boot.o
> -obj-$(CONFIG_ACPI_SLEEP) += sleep.o wakeup_$(BITS).o
> -obj-$(CONFIG_ACPI_APEI) += apei.o
> -obj-$(CONFIG_ACPI_CPPC_LIB) += cppc.o
> +obj-$(CONFIG_ACPI) += boot.o
> +obj-$(CONFIG_ACPI_SLEEP) += sleep.o wakeup_$(BITS).o
> +obj-$(CONFIG_ACPI_APEI) += apei.o
> +obj-$(CONFIG_ACPI_CPPC_LIB) += cppc.o
> +obj-$(CONFIG_X86_ACPI_MADT_WAKEUP) += madt_wakeup.o
>
> ifneq ($(CONFIG_ACPI_PROCESSOR),)
> -obj-y += cstate.o
> +obj-y += cstate.o
> endif
unintended code change?
[...]
>
> diff --git a/arch/x86/kernel/acpi/madt_wakeup.c b/arch/x86/kernel/acpi/madt_wakeup.c
> new file mode 100644
> index 000000000000..1b9747bfd5b9
> --- /dev/null
> +++ b/arch/x86/kernel/acpi/madt_wakeup.c
> @@ -0,0 +1,80 @@
> +#include <linux/acpi.h>
> +#include <asm/apic.h>
Functions like memremap(), smp_store_release() and cpu_relax() are used in this
file. Should we explicitly include the relevant headers?
> +
> +/* Physical address of the Multiprocessor Wakeup Structure mailbox */
> +static u64 acpi_mp_wake_mailbox_paddr;
> +/* Virtual address of the Multiprocessor Wakeup Structure mailbox */
> +static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox;
> +
> +static int acpi_wakeup_cpu(int apicid, unsigned long start_ip)
> +{
> + /*
> + * Remap mailbox memory only for the first call to acpi_wakeup_cpu().
> + *
> + * Wakeup of secondary CPUs is fully serialized in the core code.
> + * No need to protect acpi_mp_wake_mailbox from concurrent accesses.
> + */
> + if (!acpi_mp_wake_mailbox) {
> + acpi_mp_wake_mailbox = memremap(acpi_mp_wake_mailbox_paddr,
> + sizeof(*acpi_mp_wake_mailbox),
> + MEMREMAP_WB);
> + }
> +
> + /*
> + * Mailbox memory is shared between the firmware and OS. Firmware will
> + * listen on mailbox command address, and once it receives the wakeup
> + * command, the CPU associated with the given apicid will be booted.
> + *
> + * The value of 'apic_id' and 'wakeup_vector' must be visible to the
> + * firmware before the wakeup command is visible. smp_store_release()
> + * ensures ordering and visibility.
> + */
> + acpi_mp_wake_mailbox->apic_id = apicid;
> + acpi_mp_wake_mailbox->wakeup_vector = start_ip;
> + smp_store_release(&acpi_mp_wake_mailbox->command,
> + ACPI_MP_WAKE_COMMAND_WAKEUP);
> +
> + /*
> + * Wait for the CPU to wake up.
> + *
> + * The CPU being woken up is essentially in a spin loop waiting to be
> + * woken up. It should not take long for it wake up and acknowledge by
> + * zeroing out ->command.
> + *
> + * ACPI specification doesn't provide any guidance on how long kernel
> + * has to wait for a wake up acknowledgement. It also doesn't provide
> + * a way to cancel a wake up request if it takes too long.
> + *
> + * In TDX environment, the VMM has control over how long it takes to
> + * wake up secondary. It can postpone scheduling secondary vCPU
> + * indefinitely. Giving up on wake up request and reporting error opens
> + * possible attack vector for VMM: it can wake up a secondary CPU when
> + * kernel doesn't expect it. Wait until positive result of the wake up
> + * request.
> + */
> + while (READ_ONCE(acpi_mp_wake_mailbox->command))
> + cpu_relax();
> +
> + return 0;
> +}
> +
> +int __init acpi_parse_mp_wake(union acpi_subtable_headers *header,
> + const unsigned long end)
> +{
> + struct acpi_madt_multiproc_wakeup *mp_wake;
> +
> + if (!IS_ENABLED(CONFIG_SMP))
> + return -ENODEV;
Now you have made X86_ACPI_MADT_WAKEUP depend on SMP, and this file will only be
compiled when X86_ACPI_MADT_WAKEUP is turned on. IIUC this essentially means
IS_ENABLED(CONFIG_SMP) will always report true?
> +
> + mp_wake = (struct acpi_madt_multiproc_wakeup *)header;
> + if (BAD_MADT_ENTRY(mp_wake, end))
> + return -EINVAL;
> +
> + acpi_table_print_madt_entry(&header->common);
> +
> + acpi_mp_wake_mailbox_paddr = mp_wake->base_address;
> +
> + apic_update_callback(wakeup_secondary_cpu_64, acpi_wakeup_cpu);
> +
> + return 0;
> +}
On Fri, Oct 06, 2023 at 10:22:54AM +0000, Huang, Kai wrote:
> On Thu, 2023-10-05 at 16:13 +0300, Kirill A. Shutemov wrote:
> > In order to prepare for the expansion of support for the ACPI MADT
> > wakeup method, the relevant code has been moved into a separate file.
> > A new configuration option has been introduced to clearly indicate
> > dependencies without the use of ifdefs.
>
> Use imperative mood?
>
> - Move the relevant code into ...
> - Introduce a new configuration option to ...
Okay.
> > There have been no functional changes.
> >
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > ---
> > arch/x86/Kconfig | 7 +++
> > arch/x86/include/asm/acpi.h | 5 ++
> > arch/x86/kernel/acpi/Makefile | 11 ++--
> > arch/x86/kernel/acpi/boot.c | 86 +-----------------------------
> > arch/x86/kernel/acpi/madt_wakeup.c | 80 +++++++++++++++++++++++++++
> > 5 files changed, 99 insertions(+), 90 deletions(-)
> > create mode 100644 arch/x86/kernel/acpi/madt_wakeup.c
> >
> > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > index 3154dbc49cf5..7368d254d01f 100644
> > --- a/arch/x86/Kconfig
> > +++ b/arch/x86/Kconfig
> > @@ -1108,6 +1108,13 @@ config X86_LOCAL_APIC
> > depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
> > select IRQ_DOMAIN_HIERARCHY
> >
> > +config X86_ACPI_MADT_WAKEUP
> > + def_bool y
> > + depends on X86_64
> > + depends on ACPI
> > + depends on SMP
> > + depends on X86_LOCAL_APIC
> > +
> > config X86_IO_APIC
> > def_bool y
> > depends on X86_LOCAL_APIC || X86_UP_IOAPIC
> > diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
> > index c8a7fc23f63c..b536b5a6a57b 100644
> > --- a/arch/x86/include/asm/acpi.h
> > +++ b/arch/x86/include/asm/acpi.h
> > @@ -73,6 +73,11 @@ static inline bool acpi_skip_set_wakeup_address(void)
> >
> > #define acpi_skip_set_wakeup_address acpi_skip_set_wakeup_address
> >
> > +union acpi_subtable_headers;
> > +
> > +int __init acpi_parse_mp_wake(union acpi_subtable_headers *header,
> > + const unsigned long end);
> > +
> > /*
> > * Check if the CPU can handle C2 and deeper
> > */
> > diff --git a/arch/x86/kernel/acpi/Makefile b/arch/x86/kernel/acpi/Makefile
> > index fc17b3f136fe..8c7329c88a75 100644
> > --- a/arch/x86/kernel/acpi/Makefile
> > +++ b/arch/x86/kernel/acpi/Makefile
> > @@ -1,11 +1,12 @@
> > # SPDX-License-Identifier: GPL-2.0
> >
> > -obj-$(CONFIG_ACPI) += boot.o
> > -obj-$(CONFIG_ACPI_SLEEP) += sleep.o wakeup_$(BITS).o
> > -obj-$(CONFIG_ACPI_APEI) += apei.o
> > -obj-$(CONFIG_ACPI_CPPC_LIB) += cppc.o
> > +obj-$(CONFIG_ACPI) += boot.o
> > +obj-$(CONFIG_ACPI_SLEEP) += sleep.o wakeup_$(BITS).o
> > +obj-$(CONFIG_ACPI_APEI) += apei.o
> > +obj-$(CONFIG_ACPI_CPPC_LIB) += cppc.o
> > +obj-$(CONFIG_X86_ACPI_MADT_WAKEUP) += madt_wakeup.o
> >
> > ifneq ($(CONFIG_ACPI_PROCESSOR),)
> > -obj-y += cstate.o
> > +obj-y += cstate.o
> > endif
>
> unintended code change?
No. It keeps += aligned as they are before the patch.
>
> [...]
>
> >
> > diff --git a/arch/x86/kernel/acpi/madt_wakeup.c b/arch/x86/kernel/acpi/madt_wakeup.c
> > new file mode 100644
> > index 000000000000..1b9747bfd5b9
> > --- /dev/null
> > +++ b/arch/x86/kernel/acpi/madt_wakeup.c
> > @@ -0,0 +1,80 @@
> > +#include <linux/acpi.h>
> > +#include <asm/apic.h>
>
> Functions like memremap(), smp_store_release() and cpu_relax() are used in this
> file. Should we explicitly include the relevant headers?
Okay, will do.
> > +
> > +/* Physical address of the Multiprocessor Wakeup Structure mailbox */
> > +static u64 acpi_mp_wake_mailbox_paddr;
> > +/* Virtual address of the Multiprocessor Wakeup Structure mailbox */
> > +static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox;
> > +
> > +static int acpi_wakeup_cpu(int apicid, unsigned long start_ip)
> > +{
> > + /*
> > + * Remap mailbox memory only for the first call to acpi_wakeup_cpu().
> > + *
> > + * Wakeup of secondary CPUs is fully serialized in the core code.
> > + * No need to protect acpi_mp_wake_mailbox from concurrent accesses.
> > + */
> > + if (!acpi_mp_wake_mailbox) {
> > + acpi_mp_wake_mailbox = memremap(acpi_mp_wake_mailbox_paddr,
> > + sizeof(*acpi_mp_wake_mailbox),
> > + MEMREMAP_WB);
> > + }
> > +
> > + /*
> > + * Mailbox memory is shared between the firmware and OS. Firmware will
> > + * listen on mailbox command address, and once it receives the wakeup
> > + * command, the CPU associated with the given apicid will be booted.
> > + *
> > + * The value of 'apic_id' and 'wakeup_vector' must be visible to the
> > + * firmware before the wakeup command is visible. smp_store_release()
> > + * ensures ordering and visibility.
> > + */
> > + acpi_mp_wake_mailbox->apic_id = apicid;
> > + acpi_mp_wake_mailbox->wakeup_vector = start_ip;
> > + smp_store_release(&acpi_mp_wake_mailbox->command,
> > + ACPI_MP_WAKE_COMMAND_WAKEUP);
> > +
> > + /*
> > + * Wait for the CPU to wake up.
> > + *
> > + * The CPU being woken up is essentially in a spin loop waiting to be
> > + * woken up. It should not take long for it wake up and acknowledge by
> > + * zeroing out ->command.
> > + *
> > + * ACPI specification doesn't provide any guidance on how long kernel
> > + * has to wait for a wake up acknowledgement. It also doesn't provide
> > + * a way to cancel a wake up request if it takes too long.
> > + *
> > + * In TDX environment, the VMM has control over how long it takes to
> > + * wake up secondary. It can postpone scheduling secondary vCPU
> > + * indefinitely. Giving up on wake up request and reporting error opens
> > + * possible attack vector for VMM: it can wake up a secondary CPU when
> > + * kernel doesn't expect it. Wait until positive result of the wake up
> > + * request.
> > + */
> > + while (READ_ONCE(acpi_mp_wake_mailbox->command))
> > + cpu_relax();
> > +
> > + return 0;
> > +}
> > +
> > +int __init acpi_parse_mp_wake(union acpi_subtable_headers *header,
> > + const unsigned long end)
> > +{
> > + struct acpi_madt_multiproc_wakeup *mp_wake;
> > +
> > + if (!IS_ENABLED(CONFIG_SMP))
> > + return -ENODEV;
>
> Now you have made X86_ACPI_MADT_WAKEUP depend on SMP, and this file will only be
> compiled when X86_ACPI_MADT_WAKEUP is turned on. IIUC this essentially means
> IS_ENABLED(CONFIG_SMP) will always report true?
Good catch. I didn't have 'depends SMP' initially, but it triggered build
issue, so I added it, but forgot to drop IS_ENABLED().
> > +
> > + mp_wake = (struct acpi_madt_multiproc_wakeup *)header;
> > + if (BAD_MADT_ENTRY(mp_wake, end))
> > + return -EINVAL;
> > +
> > + acpi_table_print_madt_entry(&header->common);
> > +
> > + acpi_mp_wake_mailbox_paddr = mp_wake->base_address;
> > +
> > + apic_update_callback(wakeup_secondary_cpu_64, acpi_wakeup_cpu);
> > +
> > + return 0;
> > +}
>
Hi Kirill,
On 10/5/2023 6:13 AM, Kirill A. Shutemov wrote:
> In order to prepare for the expansion of support for the ACPI MADT
> wakeup method, the relevant code has been moved into a separate file.
> A new configuration option has been introduced to clearly indicate
> dependencies without the use of ifdefs.
>
> There have been no functional changes.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
> arch/x86/Kconfig | 7 +++
> arch/x86/include/asm/acpi.h | 5 ++
> arch/x86/kernel/acpi/Makefile | 11 ++--
> arch/x86/kernel/acpi/boot.c | 86 +-----------------------------
> arch/x86/kernel/acpi/madt_wakeup.c | 80 +++++++++++++++++++++++++++
> 5 files changed, 99 insertions(+), 90 deletions(-)
> create mode 100644 arch/x86/kernel/acpi/madt_wakeup.c
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 3154dbc49cf5..7368d254d01f 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1108,6 +1108,13 @@ config X86_LOCAL_APIC
> depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
> select IRQ_DOMAIN_HIERARCHY
>
> +config X86_ACPI_MADT_WAKEUP
> + def_bool y
> + depends on X86_64
> + depends on ACPI
> + depends on SMP
> + depends on X86_LOCAL_APIC
> +
> config X86_IO_APIC
> def_bool y
> depends on X86_LOCAL_APIC || X86_UP_IOAPIC
> diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
> index c8a7fc23f63c..b536b5a6a57b 100644
> --- a/arch/x86/include/asm/acpi.h
> +++ b/arch/x86/include/asm/acpi.h
> @@ -73,6 +73,11 @@ static inline bool acpi_skip_set_wakeup_address(void)
>
> #define acpi_skip_set_wakeup_address acpi_skip_set_wakeup_address
>
> +union acpi_subtable_headers;
> +
> +int __init acpi_parse_mp_wake(union acpi_subtable_headers *header,
> + const unsigned long end);
> +
IMO, you don't need to declare acpi_parse_mp_wake() in asm/acpi.h. Since the
only user of this function is in arch/x86/kernel/acpi, you can either create
a header file there or re-use sleep.h.
If you want to leave it here, do you want to protect it with
CONFIG_X86_ACPI_MADT_WAKEUP?
On Fri, Oct 06, 2023 at 11:33:47AM -0700, Kuppuswamy Sathyanarayanan wrote:
> Hi Kirill,
>
> On 10/5/2023 6:13 AM, Kirill A. Shutemov wrote:
> > In order to prepare for the expansion of support for the ACPI MADT
> > wakeup method, the relevant code has been moved into a separate file.
> > A new configuration option has been introduced to clearly indicate
> > dependencies without the use of ifdefs.
> >
> > There have been no functional changes.
> >
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > ---
> > arch/x86/Kconfig | 7 +++
> > arch/x86/include/asm/acpi.h | 5 ++
> > arch/x86/kernel/acpi/Makefile | 11 ++--
> > arch/x86/kernel/acpi/boot.c | 86 +-----------------------------
> > arch/x86/kernel/acpi/madt_wakeup.c | 80 +++++++++++++++++++++++++++
> > 5 files changed, 99 insertions(+), 90 deletions(-)
> > create mode 100644 arch/x86/kernel/acpi/madt_wakeup.c
> >
> > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > index 3154dbc49cf5..7368d254d01f 100644
> > --- a/arch/x86/Kconfig
> > +++ b/arch/x86/Kconfig
> > @@ -1108,6 +1108,13 @@ config X86_LOCAL_APIC
> > depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
> > select IRQ_DOMAIN_HIERARCHY
> >
> > +config X86_ACPI_MADT_WAKEUP
> > + def_bool y
> > + depends on X86_64
> > + depends on ACPI
> > + depends on SMP
> > + depends on X86_LOCAL_APIC
> > +
> > config X86_IO_APIC
> > def_bool y
> > depends on X86_LOCAL_APIC || X86_UP_IOAPIC
> > diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
> > index c8a7fc23f63c..b536b5a6a57b 100644
> > --- a/arch/x86/include/asm/acpi.h
> > +++ b/arch/x86/include/asm/acpi.h
> > @@ -73,6 +73,11 @@ static inline bool acpi_skip_set_wakeup_address(void)
> >
> > #define acpi_skip_set_wakeup_address acpi_skip_set_wakeup_address
> >
> > +union acpi_subtable_headers;
> > +
> > +int __init acpi_parse_mp_wake(union acpi_subtable_headers *header,
> > + const unsigned long end);
> > +
>
> IMO, you don't need to declare acpi_parse_mp_wake() in asm/acpi.h. Since the
> only user of this function is in arch/x86/kernel/acpi, you can either create
> a header file there or re-use sleep.h.
Is it a really a bid deal? I don't see how it fits into sleep.h and
introducing one more header file for one declaration seems excessive.
> If you want to leave it here, do you want to protect it with
> CONFIG_X86_ACPI_MADT_WAKEUP?
Declarations are harmless if nobody uses them. Needless ifdeffery hurts
eyes :P
@@ -1108,6 +1108,13 @@ config X86_LOCAL_APIC
depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
select IRQ_DOMAIN_HIERARCHY
+config X86_ACPI_MADT_WAKEUP
+ def_bool y
+ depends on X86_64
+ depends on ACPI
+ depends on SMP
+ depends on X86_LOCAL_APIC
+
config X86_IO_APIC
def_bool y
depends on X86_LOCAL_APIC || X86_UP_IOAPIC
@@ -73,6 +73,11 @@ static inline bool acpi_skip_set_wakeup_address(void)
#define acpi_skip_set_wakeup_address acpi_skip_set_wakeup_address
+union acpi_subtable_headers;
+
+int __init acpi_parse_mp_wake(union acpi_subtable_headers *header,
+ const unsigned long end);
+
/*
* Check if the CPU can handle C2 and deeper
*/
@@ -1,11 +1,12 @@
# SPDX-License-Identifier: GPL-2.0
-obj-$(CONFIG_ACPI) += boot.o
-obj-$(CONFIG_ACPI_SLEEP) += sleep.o wakeup_$(BITS).o
-obj-$(CONFIG_ACPI_APEI) += apei.o
-obj-$(CONFIG_ACPI_CPPC_LIB) += cppc.o
+obj-$(CONFIG_ACPI) += boot.o
+obj-$(CONFIG_ACPI_SLEEP) += sleep.o wakeup_$(BITS).o
+obj-$(CONFIG_ACPI_APEI) += apei.o
+obj-$(CONFIG_ACPI_CPPC_LIB) += cppc.o
+obj-$(CONFIG_X86_ACPI_MADT_WAKEUP) += madt_wakeup.o
ifneq ($(CONFIG_ACPI_PROCESSOR),)
-obj-y += cstate.o
+obj-y += cstate.o
endif
@@ -66,13 +66,6 @@ static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
static bool acpi_support_online_capable;
#endif
-#ifdef CONFIG_X86_64
-/* Physical address of the Multiprocessor Wakeup Structure mailbox */
-static u64 acpi_mp_wake_mailbox_paddr;
-/* Virtual address of the Multiprocessor Wakeup Structure mailbox */
-static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox;
-#endif
-
#ifdef CONFIG_X86_IO_APIC
/*
* Locks related to IOAPIC hotplug
@@ -357,60 +350,6 @@ acpi_parse_lapic_nmi(union acpi_subtable_headers * header, const unsigned long e
return 0;
}
-
-#ifdef CONFIG_X86_64
-static int acpi_wakeup_cpu(int apicid, unsigned long start_ip)
-{
- /*
- * Remap mailbox memory only for the first call to acpi_wakeup_cpu().
- *
- * Wakeup of secondary CPUs is fully serialized in the core code.
- * No need to protect acpi_mp_wake_mailbox from concurrent accesses.
- */
- if (!acpi_mp_wake_mailbox) {
- acpi_mp_wake_mailbox = memremap(acpi_mp_wake_mailbox_paddr,
- sizeof(*acpi_mp_wake_mailbox),
- MEMREMAP_WB);
- }
-
- /*
- * Mailbox memory is shared between the firmware and OS. Firmware will
- * listen on mailbox command address, and once it receives the wakeup
- * command, the CPU associated with the given apicid will be booted.
- *
- * The value of 'apic_id' and 'wakeup_vector' must be visible to the
- * firmware before the wakeup command is visible. smp_store_release()
- * ensures ordering and visibility.
- */
- acpi_mp_wake_mailbox->apic_id = apicid;
- acpi_mp_wake_mailbox->wakeup_vector = start_ip;
- smp_store_release(&acpi_mp_wake_mailbox->command,
- ACPI_MP_WAKE_COMMAND_WAKEUP);
-
- /*
- * Wait for the CPU to wake up.
- *
- * The CPU being woken up is essentially in a spin loop waiting to be
- * woken up. It should not take long for it wake up and acknowledge by
- * zeroing out ->command.
- *
- * ACPI specification doesn't provide any guidance on how long kernel
- * has to wait for a wake up acknowledgement. It also doesn't provide
- * a way to cancel a wake up request if it takes too long.
- *
- * In TDX environment, the VMM has control over how long it takes to
- * wake up secondary. It can postpone scheduling secondary vCPU
- * indefinitely. Giving up on wake up request and reporting error opens
- * possible attack vector for VMM: it can wake up a secondary CPU when
- * kernel doesn't expect it. Wait until positive result of the wake up
- * request.
- */
- while (READ_ONCE(acpi_mp_wake_mailbox->command))
- cpu_relax();
-
- return 0;
-}
-#endif /* CONFIG_X86_64 */
#endif /* CONFIG_X86_LOCAL_APIC */
#ifdef CONFIG_X86_IO_APIC
@@ -1160,29 +1099,6 @@ static int __init acpi_parse_madt_lapic_entries(void)
}
return 0;
}
-
-#ifdef CONFIG_X86_64
-static int __init acpi_parse_mp_wake(union acpi_subtable_headers *header,
- const unsigned long end)
-{
- struct acpi_madt_multiproc_wakeup *mp_wake;
-
- if (!IS_ENABLED(CONFIG_SMP))
- return -ENODEV;
-
- mp_wake = (struct acpi_madt_multiproc_wakeup *)header;
- if (BAD_MADT_ENTRY(mp_wake, end))
- return -EINVAL;
-
- acpi_table_print_madt_entry(&header->common);
-
- acpi_mp_wake_mailbox_paddr = mp_wake->base_address;
-
- apic_update_callback(wakeup_secondary_cpu_64, acpi_wakeup_cpu);
-
- return 0;
-}
-#endif /* CONFIG_X86_64 */
#endif /* CONFIG_X86_LOCAL_APIC */
#ifdef CONFIG_X86_IO_APIC
@@ -1379,7 +1295,7 @@ static void __init acpi_process_madt(void)
smp_found_config = 1;
}
-#ifdef CONFIG_X86_64
+#ifdef CONFIG_X86_ACPI_MADT_WAKEUP
/*
* Parse MADT MP Wake entry.
*/
new file mode 100644
@@ -0,0 +1,80 @@
+#include <linux/acpi.h>
+#include <asm/apic.h>
+
+/* Physical address of the Multiprocessor Wakeup Structure mailbox */
+static u64 acpi_mp_wake_mailbox_paddr;
+/* Virtual address of the Multiprocessor Wakeup Structure mailbox */
+static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox;
+
+static int acpi_wakeup_cpu(int apicid, unsigned long start_ip)
+{
+ /*
+ * Remap mailbox memory only for the first call to acpi_wakeup_cpu().
+ *
+ * Wakeup of secondary CPUs is fully serialized in the core code.
+ * No need to protect acpi_mp_wake_mailbox from concurrent accesses.
+ */
+ if (!acpi_mp_wake_mailbox) {
+ acpi_mp_wake_mailbox = memremap(acpi_mp_wake_mailbox_paddr,
+ sizeof(*acpi_mp_wake_mailbox),
+ MEMREMAP_WB);
+ }
+
+ /*
+ * Mailbox memory is shared between the firmware and OS. Firmware will
+ * listen on mailbox command address, and once it receives the wakeup
+ * command, the CPU associated with the given apicid will be booted.
+ *
+ * The value of 'apic_id' and 'wakeup_vector' must be visible to the
+ * firmware before the wakeup command is visible. smp_store_release()
+ * ensures ordering and visibility.
+ */
+ acpi_mp_wake_mailbox->apic_id = apicid;
+ acpi_mp_wake_mailbox->wakeup_vector = start_ip;
+ smp_store_release(&acpi_mp_wake_mailbox->command,
+ ACPI_MP_WAKE_COMMAND_WAKEUP);
+
+ /*
+ * Wait for the CPU to wake up.
+ *
+ * The CPU being woken up is essentially in a spin loop waiting to be
+ * woken up. It should not take long for it wake up and acknowledge by
+ * zeroing out ->command.
+ *
+ * ACPI specification doesn't provide any guidance on how long kernel
+ * has to wait for a wake up acknowledgement. It also doesn't provide
+ * a way to cancel a wake up request if it takes too long.
+ *
+ * In TDX environment, the VMM has control over how long it takes to
+ * wake up secondary. It can postpone scheduling secondary vCPU
+ * indefinitely. Giving up on wake up request and reporting error opens
+ * possible attack vector for VMM: it can wake up a secondary CPU when
+ * kernel doesn't expect it. Wait until positive result of the wake up
+ * request.
+ */
+ while (READ_ONCE(acpi_mp_wake_mailbox->command))
+ cpu_relax();
+
+ return 0;
+}
+
+int __init acpi_parse_mp_wake(union acpi_subtable_headers *header,
+ const unsigned long end)
+{
+ struct acpi_madt_multiproc_wakeup *mp_wake;
+
+ if (!IS_ENABLED(CONFIG_SMP))
+ return -ENODEV;
+
+ mp_wake = (struct acpi_madt_multiproc_wakeup *)header;
+ if (BAD_MADT_ENTRY(mp_wake, end))
+ return -EINVAL;
+
+ acpi_table_print_madt_entry(&header->common);
+
+ acpi_mp_wake_mailbox_paddr = mp_wake->base_address;
+
+ apic_update_callback(wakeup_secondary_cpu_64, acpi_wakeup_cpu);
+
+ return 0;
+}