| Message ID | 20210601142103.6378-1-sathyanarayanan.kuppuswamy@linux.intel.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | [v6,1/1] x86/acpi, x86/boot: Add multiprocessor wake-up support | expand |
On Tue, Jun 1, 2021 at 4:21 PM Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> wrote: > > As per ACPI specification r6.4, sec 5.2.12.19, a new sub > structure – multiprocessor wake-up structure - is added to the > ACPI Multiple APIC Description Table (MADT) to describe the > information of the mailbox. If a platform firmware produces the > multiprocessor wake-up structure, then OS may use this new > mailbox-based mechanism to wake up the APs. > > Add ACPI MADT wake table parsing support for x86 platform and if > MADT wake table is present, update apic->wakeup_secondary_cpu with > new API which uses MADT wake mailbox to wake-up CPU. > > Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com> > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > Reviewed-by: Andi Kleen <ak@linux.intel.com> All of my comments have been addressed, so Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > > Changes since v5: > * None ( CCed ACPI list) > > Changes since v4: > * Used smp_store_release() in place of WRITE_ONCE(). > * Addressed some checkpatch warnings. > > Changes since v3: > * Removed acpi_mp_wake_mailbox_init() and moved init code to > acpi_wakeup_cpu(). > * Removed redundant NULL pointer check for acpi_mp_wake_mailbox. > * Added comments/debug prints as per Rafael's suggestion. > * Removed MADT/SVKL ACPI patches from this patchset. It will be > merged via ACPICA submission. > > arch/x86/include/asm/apic.h | 3 ++ > arch/x86/kernel/acpi/boot.c | 96 +++++++++++++++++++++++++++++++++++++ > arch/x86/kernel/apic/apic.c | 8 ++++ > 3 files changed, 107 insertions(+) > > diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h > index 412b51e059c8..3e94e1f402ea 100644 > --- a/arch/x86/include/asm/apic.h > +++ b/arch/x86/include/asm/apic.h > @@ -487,6 +487,9 @@ static inline unsigned int read_apic_id(void) > return apic->get_apic_id(reg); > } > > +typedef int (*wakeup_cpu_handler)(int apicid, unsigned long start_eip); > +extern void acpi_wake_cpu_handler_update(wakeup_cpu_handler handler); > + > extern int default_apic_id_valid(u32 apicid); > extern int default_acpi_madt_oem_check(char *, char *); > extern void default_setup_apic_routing(void); > diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c > index 14cd3186dc77..c51134eb55d0 100644 > --- a/arch/x86/kernel/acpi/boot.c > +++ b/arch/x86/kernel/acpi/boot.c > @@ -65,6 +65,10 @@ int acpi_fix_pin2_polarity __initdata; > static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE; > #endif > > +static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox; > +static u64 acpi_mp_wake_mailbox_paddr; > +static physid_mask_t apic_id_wakemap = PHYSID_MASK_NONE; > + > #ifdef CONFIG_X86_IO_APIC > /* > * Locks related to IOAPIC hotplug > @@ -329,6 +333,68 @@ acpi_parse_lapic_nmi(union acpi_subtable_headers * header, const unsigned long e > return 0; > } > > +static int acpi_wakeup_cpu(int apicid, unsigned long start_ip) > +{ > + u8 timeout = 0xFF; > + > + /* Remap mailbox memory only for the first call to acpi_wakeup_cpu() */ > + if (physids_empty(apic_id_wakemap)) { > + acpi_mp_wake_mailbox = memremap(acpi_mp_wake_mailbox_paddr, > + sizeof(*acpi_mp_wake_mailbox), > + MEMREMAP_WB); > + } > + > + /* > + * According to the ACPI specification r6.4, sec 5.2.12.19, the > + * mailbox-based wakeup mechanism cannot be used more than once > + * for the same CPU, so skip sending wake commands to already > + * awake CPU. > + */ > + if (physid_isset(apicid, apic_id_wakemap)) { > + pr_err("CPU already awake (APIC ID %x), skipping wakeup\n", > + apicid); > + return -EINVAL; > + } > + > + /* > + * Mailbox memory is shared between firmware and OS. Firmware will > + * listen on mailbox command address, and once it receives the wakeup > + * command, CPU associated with the given apicid will be booted. So, > + * the value of apic_id and wakeup_vector has to be set before updating > + * the wakeup command. So use smp_store_release to let the compiler know > + * about it and preserve the order of writes. > + */ > + smp_store_release(&acpi_mp_wake_mailbox->apic_id, apicid); > + smp_store_release(&acpi_mp_wake_mailbox->wakeup_vector, start_ip); > + smp_store_release(&acpi_mp_wake_mailbox->command, > + ACPI_MP_WAKE_COMMAND_WAKEUP); > + > + /* > + * After writing wakeup command, wait for maximum timeout of 0xFF > + * for firmware to reset the command address back zero to indicate > + * the successful reception of command. > + * NOTE: 255 as timeout value is decided based on our experiments. > + * > + * XXX: Change the timeout once ACPI specification comes up with > + * standard maximum timeout value. > + */ > + while (READ_ONCE(acpi_mp_wake_mailbox->command) && timeout--) > + cpu_relax(); > + > + if (timeout) { > + /* > + * If the CPU wakeup process is successful, store the > + * status in apic_id_wakemap to prevent re-wakeup > + * requests. > + */ > + physid_set(apicid, apic_id_wakemap); > + return 0; > + } > + > + /* If timed out (timeout == 0), return error */ > + return -EIO; > +} > + > #endif /*CONFIG_X86_LOCAL_APIC */ > > #ifdef CONFIG_X86_IO_APIC > @@ -1086,6 +1152,30 @@ static int __init acpi_parse_madt_lapic_entries(void) > } > return 0; > } > + > +static int __init acpi_parse_mp_wake(union acpi_subtable_headers *header, > + const unsigned long end) > +{ > + struct acpi_madt_multiproc_wakeup *mp_wake; > + > + if (acpi_mp_wake_mailbox) > + return -EINVAL; > + > + 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; > + > + acpi_wake_cpu_handler_update(acpi_wakeup_cpu); > + > + return 0; > +} > #endif /* CONFIG_X86_LOCAL_APIC */ > > #ifdef CONFIG_X86_IO_APIC > @@ -1284,6 +1374,12 @@ static void __init acpi_process_madt(void) > > smp_found_config = 1; > } > + > + /* > + * Parse MADT MP Wake entry. > + */ > + acpi_table_parse_madt(ACPI_MADT_TYPE_MULTIPROC_WAKEUP, > + acpi_parse_mp_wake, 1); > } > if (error == -EINVAL) { > /* > diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c > index 4f26700f314d..f1b90a4b89e8 100644 > --- a/arch/x86/kernel/apic/apic.c > +++ b/arch/x86/kernel/apic/apic.c > @@ -2554,6 +2554,14 @@ u32 x86_msi_msg_get_destid(struct msi_msg *msg, bool extid) > } > EXPORT_SYMBOL_GPL(x86_msi_msg_get_destid); > > +void __init acpi_wake_cpu_handler_update(wakeup_cpu_handler handler) > +{ > + struct apic **drv; > + > + for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) > + (*drv)->wakeup_secondary_cpu = handler; > +} > + > /* > * Override the generic EOI implementation with an optimized version. > * Only called during early boot when only one CPU is active and with > -- > 2.25.1 >
On 6/1/21 10:36 AM, Rafael J. Wysocki wrote: >> As per ACPI specification r6.4, sec 5.2.12.19, a new sub >> structure – multiprocessor wake-up structure - is added to the >> ACPI Multiple APIC Description Table (MADT) to describe the >> information of the mailbox. If a platform firmware produces the >> multiprocessor wake-up structure, then OS may use this new >> mailbox-based mechanism to wake up the APs. >> >> Add ACPI MADT wake table parsing support for x86 platform and if >> MADT wake table is present, update apic->wakeup_secondary_cpu with >> new API which uses MADT wake mailbox to wake-up CPU. >> >> Co-developed-by: Sean Christopherson<sean.j.christopherson@intel.com> >> Signed-off-by: Sean Christopherson<sean.j.christopherson@intel.com> >> Signed-off-by: Kuppuswamy Sathyanarayanan<sathyanarayanan.kuppuswamy@linux.intel.com> >> Reviewed-by: Andi Kleen<ak@linux.intel.com> > All of my comments have been addressed, so > > Reviewed-by: Rafael J. Wysocki<rafael.j.wysocki@intel.com> Thomas/Peter Z, Gentle ping. Any comments? >
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index 412b51e059c8..3e94e1f402ea 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -487,6 +487,9 @@ static inline unsigned int read_apic_id(void) return apic->get_apic_id(reg); } +typedef int (*wakeup_cpu_handler)(int apicid, unsigned long start_eip); +extern void acpi_wake_cpu_handler_update(wakeup_cpu_handler handler); + extern int default_apic_id_valid(u32 apicid); extern int default_acpi_madt_oem_check(char *, char *); extern void default_setup_apic_routing(void); diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 14cd3186dc77..c51134eb55d0 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -65,6 +65,10 @@ int acpi_fix_pin2_polarity __initdata; static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE; #endif +static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox; +static u64 acpi_mp_wake_mailbox_paddr; +static physid_mask_t apic_id_wakemap = PHYSID_MASK_NONE; + #ifdef CONFIG_X86_IO_APIC /* * Locks related to IOAPIC hotplug @@ -329,6 +333,68 @@ acpi_parse_lapic_nmi(union acpi_subtable_headers * header, const unsigned long e return 0; } +static int acpi_wakeup_cpu(int apicid, unsigned long start_ip) +{ + u8 timeout = 0xFF; + + /* Remap mailbox memory only for the first call to acpi_wakeup_cpu() */ + if (physids_empty(apic_id_wakemap)) { + acpi_mp_wake_mailbox = memremap(acpi_mp_wake_mailbox_paddr, + sizeof(*acpi_mp_wake_mailbox), + MEMREMAP_WB); + } + + /* + * According to the ACPI specification r6.4, sec 5.2.12.19, the + * mailbox-based wakeup mechanism cannot be used more than once + * for the same CPU, so skip sending wake commands to already + * awake CPU. + */ + if (physid_isset(apicid, apic_id_wakemap)) { + pr_err("CPU already awake (APIC ID %x), skipping wakeup\n", + apicid); + return -EINVAL; + } + + /* + * Mailbox memory is shared between firmware and OS. Firmware will + * listen on mailbox command address, and once it receives the wakeup + * command, CPU associated with the given apicid will be booted. So, + * the value of apic_id and wakeup_vector has to be set before updating + * the wakeup command. So use smp_store_release to let the compiler know + * about it and preserve the order of writes. + */ + smp_store_release(&acpi_mp_wake_mailbox->apic_id, apicid); + smp_store_release(&acpi_mp_wake_mailbox->wakeup_vector, start_ip); + smp_store_release(&acpi_mp_wake_mailbox->command, + ACPI_MP_WAKE_COMMAND_WAKEUP); + + /* + * After writing wakeup command, wait for maximum timeout of 0xFF + * for firmware to reset the command address back zero to indicate + * the successful reception of command. + * NOTE: 255 as timeout value is decided based on our experiments. + * + * XXX: Change the timeout once ACPI specification comes up with + * standard maximum timeout value. + */ + while (READ_ONCE(acpi_mp_wake_mailbox->command) && timeout--) + cpu_relax(); + + if (timeout) { + /* + * If the CPU wakeup process is successful, store the + * status in apic_id_wakemap to prevent re-wakeup + * requests. + */ + physid_set(apicid, apic_id_wakemap); + return 0; + } + + /* If timed out (timeout == 0), return error */ + return -EIO; +} + #endif /*CONFIG_X86_LOCAL_APIC */ #ifdef CONFIG_X86_IO_APIC @@ -1086,6 +1152,30 @@ static int __init acpi_parse_madt_lapic_entries(void) } return 0; } + +static int __init acpi_parse_mp_wake(union acpi_subtable_headers *header, + const unsigned long end) +{ + struct acpi_madt_multiproc_wakeup *mp_wake; + + if (acpi_mp_wake_mailbox) + return -EINVAL; + + 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; + + acpi_wake_cpu_handler_update(acpi_wakeup_cpu); + + return 0; +} #endif /* CONFIG_X86_LOCAL_APIC */ #ifdef CONFIG_X86_IO_APIC @@ -1284,6 +1374,12 @@ static void __init acpi_process_madt(void) smp_found_config = 1; } + + /* + * Parse MADT MP Wake entry. + */ + acpi_table_parse_madt(ACPI_MADT_TYPE_MULTIPROC_WAKEUP, + acpi_parse_mp_wake, 1); } if (error == -EINVAL) { /* diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 4f26700f314d..f1b90a4b89e8 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2554,6 +2554,14 @@ u32 x86_msi_msg_get_destid(struct msi_msg *msg, bool extid) } EXPORT_SYMBOL_GPL(x86_msi_msg_get_destid); +void __init acpi_wake_cpu_handler_update(wakeup_cpu_handler handler) +{ + struct apic **drv; + + for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) + (*drv)->wakeup_secondary_cpu = handler; +} + /* * Override the generic EOI implementation with an optimized version. * Only called during early boot when only one CPU is active and with