x86/acpi: Extract ACPI MADT wakeup code into a separate file

In order to prepare for the expansion of support for the ACPI MADT
wakeup method, move the relevant code into a separate file.

Introduce a new configuration option 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>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Kai Huang <kai.huang@intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Tao Liu <ltao@redhat.com>
Link: https://lore.kernel.org/r/20240614095904.1345461-2-kirill.shutemov@linux.intel.com

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1d7122a1883e8265fb9be256bf8efa680d02191b..125914536825905b76e5f4a0fa8f05bee2d6c832 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1118,6 +1118,13 @@ config X86_LOCAL_APIC
        depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
        select IRQ_DOMAIN_HIERARCHY
 
+config 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 5af926c050f0944d1981a2a86bd960bc82f66444..ceacac2b335d5e5c4d8b274b2b16435ad8a8ff6d 100644 (file)
--- a/arch/x86/include/asm/acpi.h
+++ b/arch/x86/include/asm/acpi.h
@@ -78,6 +78,11 @@ 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 fc17b3f136fec09f8bb4b517a11d045359982414..2feba7257665adb4ed7ad45c7ba742d7dad72054 100644 (file)
--- a/arch/x86/kernel/acpi/Makefile
+++ b/arch/x86/kernel/acpi/Makefile
@@ -4,6 +4,7 @@ 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_MADT_WAKEUP) += madt_wakeup.o
 
 ifneq ($(CONFIG_ACPI_PROCESSOR),)
 obj-y                          += cstate.o

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 4bf82dbd2a6b5a0b59ba201e397bd06cfdfdbe38..9f4618dcd7046555f79596cdad736375b9772a59 100644 (file)
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -67,13 +67,6 @@ static bool has_lapic_cpus __initdata;
 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
@@ -341,60 +334,6 @@ acpi_parse_lapic_nmi(union acpi_subtable_headers * header, const unsigned long e
 
        return 0;
 }
-
-#ifdef CONFIG_X86_64
-static int acpi_wakeup_cpu(u32 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
@@ -1124,29 +1063,6 @@ 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
@@ -1343,7 +1259,7 @@ static void __init acpi_process_madt(void)
                                smp_found_config = 1;
                        }
 
-#ifdef CONFIG_X86_64
+#ifdef CONFIG_ACPI_MADT_WAKEUP
                        /*
                         * Parse MADT MP Wake entry.
                         */

diff --git a/arch/x86/kernel/acpi/madt_wakeup.c b/arch/x86/kernel/acpi/madt_wakeup.c
new file mode 100644 (file)
index 0000000..7f164d3
--- /dev/null
+++ b/arch/x86/kernel/acpi/madt_wakeup.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/acpi.h>
+#include <linux/io.h>
+#include <asm/apic.h>
+#include <asm/barrier.h>
+#include <asm/processor.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(u32 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 acknowledgment. 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;
+
+       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;
+}