diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/xen/xen-acpi-cpuhotplug.c | 446 |
1 files changed, 446 insertions, 0 deletions
diff --git a/drivers/xen/xen-acpi-cpuhotplug.c b/drivers/xen/xen-acpi-cpuhotplug.c new file mode 100644 index 000000000..00ab1ece0 --- /dev/null +++ b/drivers/xen/xen-acpi-cpuhotplug.c @@ -0,0 +1,446 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2012 Intel Corporation + * Author: Liu Jinsong <jinsong.liu@intel.com> + * Author: Jiang Yunhong <yunhong.jiang@intel.com> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/types.h> +#include <linux/cpu.h> +#include <linux/acpi.h> +#include <linux/uaccess.h> +#include <acpi/processor.h> +#include <xen/acpi.h> +#include <xen/interface/platform.h> +#include <asm/xen/hypercall.h> + +#define PREFIX "ACPI:xen_cpu_hotplug:" + +#define INSTALL_NOTIFY_HANDLER 0 +#define UNINSTALL_NOTIFY_HANDLER 1 + +static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr); + +/* -------------------------------------------------------------------------- + Driver Interface +-------------------------------------------------------------------------- */ + +static int xen_acpi_processor_enable(struct acpi_device *device) +{ + acpi_status status = 0; + unsigned long long value; + union acpi_object object = { 0 }; + struct acpi_buffer buffer = { sizeof(union acpi_object), &object }; + struct acpi_processor *pr = acpi_driver_data(device); + + if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) { + /* Declared with "Processor" statement; match ProcessorID */ + status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer); + if (ACPI_FAILURE(status)) { + pr_err(PREFIX "Evaluating processor object\n"); + return -ENODEV; + } + + pr->acpi_id = object.processor.proc_id; + } else { + /* Declared with "Device" statement; match _UID */ + status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID, + NULL, &value); + if (ACPI_FAILURE(status)) { + pr_err(PREFIX "Evaluating processor _UID\n"); + return -ENODEV; + } + + pr->acpi_id = value; + } + + pr->id = xen_pcpu_id(pr->acpi_id); + + if (invalid_logical_cpuid(pr->id)) + /* This cpu is not presented at hypervisor, try to hotadd it */ + if (ACPI_FAILURE(xen_acpi_cpu_hotadd(pr))) { + pr_err(PREFIX "Hotadd CPU (acpi_id = %d) failed.\n", + pr->acpi_id); + return -ENODEV; + } + + return 0; +} + +static int xen_acpi_processor_add(struct acpi_device *device) +{ + int ret; + struct acpi_processor *pr; + + if (!device) + return -EINVAL; + + pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL); + if (!pr) + return -ENOMEM; + + pr->handle = device->handle; + strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME); + strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS); + device->driver_data = pr; + + ret = xen_acpi_processor_enable(device); + if (ret) + pr_err(PREFIX "Error when enabling Xen processor\n"); + + return ret; +} + +static int xen_acpi_processor_remove(struct acpi_device *device) +{ + struct acpi_processor *pr; + + if (!device) + return -EINVAL; + + pr = acpi_driver_data(device); + if (!pr) + return -EINVAL; + + kfree(pr); + return 0; +} + +/*-------------------------------------------------------------- + Acpi processor hotplug support +--------------------------------------------------------------*/ + +static int is_processor_present(acpi_handle handle) +{ + acpi_status status; + unsigned long long sta = 0; + + + status = acpi_evaluate_integer(handle, "_STA", NULL, &sta); + + if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_PRESENT)) + return 1; + + /* + * _STA is mandatory for a processor that supports hot plug + */ + if (status == AE_NOT_FOUND) + pr_info(PREFIX "Processor does not support hot plug\n"); + else + pr_info(PREFIX "Processor Device is not present"); + return 0; +} + +static int xen_apic_id(acpi_handle handle) +{ + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; + union acpi_object *obj; + struct acpi_madt_local_apic *lapic; + int apic_id; + + if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer))) + return -EINVAL; + + if (!buffer.length || !buffer.pointer) + return -EINVAL; + + obj = buffer.pointer; + if (obj->type != ACPI_TYPE_BUFFER || + obj->buffer.length < sizeof(*lapic)) { + kfree(buffer.pointer); + return -EINVAL; + } + + lapic = (struct acpi_madt_local_apic *)obj->buffer.pointer; + + if (lapic->header.type != ACPI_MADT_TYPE_LOCAL_APIC || + !(lapic->lapic_flags & ACPI_MADT_ENABLED)) { + kfree(buffer.pointer); + return -EINVAL; + } + + apic_id = (uint32_t)lapic->id; + kfree(buffer.pointer); + buffer.length = ACPI_ALLOCATE_BUFFER; + buffer.pointer = NULL; + + return apic_id; +} + +static int xen_hotadd_cpu(struct acpi_processor *pr) +{ + int cpu_id, apic_id, pxm; + struct xen_platform_op op; + + apic_id = xen_apic_id(pr->handle); + if (apic_id < 0) { + pr_err(PREFIX "Failed to get apic_id for acpi_id %d\n", + pr->acpi_id); + return -ENODEV; + } + + pxm = xen_acpi_get_pxm(pr->handle); + if (pxm < 0) { + pr_err(PREFIX "Failed to get _PXM for acpi_id %d\n", + pr->acpi_id); + return pxm; + } + + op.cmd = XENPF_cpu_hotadd; + op.u.cpu_add.apic_id = apic_id; + op.u.cpu_add.acpi_id = pr->acpi_id; + op.u.cpu_add.pxm = pxm; + + cpu_id = HYPERVISOR_platform_op(&op); + if (cpu_id < 0) + pr_err(PREFIX "Failed to hotadd CPU for acpi_id %d\n", + pr->acpi_id); + + return cpu_id; +} + +static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr) +{ + if (!is_processor_present(pr->handle)) + return AE_ERROR; + + pr->id = xen_hotadd_cpu(pr); + if (invalid_logical_cpuid(pr->id)) + return AE_ERROR; + + /* + * Sync with Xen hypervisor, providing new /sys/.../xen_cpuX + * interface after cpu hotadded. + */ + xen_pcpu_hotplug_sync(); + + return AE_OK; +} + +static int acpi_processor_device_remove(struct acpi_device *device) +{ + pr_debug(PREFIX "Xen does not support CPU hotremove\n"); + + return -ENOSYS; +} + +static void acpi_processor_hotplug_notify(acpi_handle handle, + u32 event, void *data) +{ + struct acpi_processor *pr; + struct acpi_device *device = NULL; + u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */ + int result; + + acpi_scan_lock_acquire(); + + switch (event) { + case ACPI_NOTIFY_BUS_CHECK: + case ACPI_NOTIFY_DEVICE_CHECK: + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "Processor driver received %s event\n", + (event == ACPI_NOTIFY_BUS_CHECK) ? + "ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK")); + + if (!is_processor_present(handle)) + break; + + acpi_bus_get_device(handle, &device); + if (acpi_device_enumerated(device)) + break; + + result = acpi_bus_scan(handle); + if (result) { + pr_err(PREFIX "Unable to add the device\n"); + break; + } + device = NULL; + acpi_bus_get_device(handle, &device); + if (!acpi_device_enumerated(device)) { + pr_err(PREFIX "Missing device object\n"); + break; + } + ost_code = ACPI_OST_SC_SUCCESS; + break; + + case ACPI_NOTIFY_EJECT_REQUEST: + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "received ACPI_NOTIFY_EJECT_REQUEST\n")); + + if (acpi_bus_get_device(handle, &device)) { + pr_err(PREFIX "Device don't exist, dropping EJECT\n"); + break; + } + pr = acpi_driver_data(device); + if (!pr) { + pr_err(PREFIX "Driver data is NULL, dropping EJECT\n"); + break; + } + + /* + * TBD: implement acpi_processor_device_remove if Xen support + * CPU hotremove in the future. + */ + acpi_processor_device_remove(device); + break; + + default: + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "Unsupported event [0x%x]\n", event)); + + /* non-hotplug event; possibly handled by other handler */ + goto out; + } + + (void) acpi_evaluate_ost(handle, event, ost_code, NULL); + +out: + acpi_scan_lock_release(); +} + +static acpi_status is_processor_device(acpi_handle handle) +{ + struct acpi_device_info *info; + char *hid; + acpi_status status; + + status = acpi_get_object_info(handle, &info); + if (ACPI_FAILURE(status)) + return status; + + if (info->type == ACPI_TYPE_PROCESSOR) { + kfree(info); + return AE_OK; /* found a processor object */ + } + + if (!(info->valid & ACPI_VALID_HID)) { + kfree(info); + return AE_ERROR; + } + + hid = info->hardware_id.string; + if ((hid == NULL) || strcmp(hid, ACPI_PROCESSOR_DEVICE_HID)) { + kfree(info); + return AE_ERROR; + } + + kfree(info); + return AE_OK; /* found a processor device object */ +} + +static acpi_status +processor_walk_namespace_cb(acpi_handle handle, + u32 lvl, void *context, void **rv) +{ + acpi_status status; + int *action = context; + + status = is_processor_device(handle); + if (ACPI_FAILURE(status)) + return AE_OK; /* not a processor; continue to walk */ + + switch (*action) { + case INSTALL_NOTIFY_HANDLER: + acpi_install_notify_handler(handle, + ACPI_SYSTEM_NOTIFY, + acpi_processor_hotplug_notify, + NULL); + break; + case UNINSTALL_NOTIFY_HANDLER: + acpi_remove_notify_handler(handle, + ACPI_SYSTEM_NOTIFY, + acpi_processor_hotplug_notify); + break; + default: + break; + } + + /* found a processor; skip walking underneath */ + return AE_CTRL_DEPTH; +} + +static +void acpi_processor_install_hotplug_notify(void) +{ + int action = INSTALL_NOTIFY_HANDLER; + acpi_walk_namespace(ACPI_TYPE_ANY, + ACPI_ROOT_OBJECT, + ACPI_UINT32_MAX, + processor_walk_namespace_cb, NULL, &action, NULL); +} + +static +void acpi_processor_uninstall_hotplug_notify(void) +{ + int action = UNINSTALL_NOTIFY_HANDLER; + acpi_walk_namespace(ACPI_TYPE_ANY, + ACPI_ROOT_OBJECT, + ACPI_UINT32_MAX, + processor_walk_namespace_cb, NULL, &action, NULL); +} + +static const struct acpi_device_id processor_device_ids[] = { + {ACPI_PROCESSOR_OBJECT_HID, 0}, + {ACPI_PROCESSOR_DEVICE_HID, 0}, + {"", 0}, +}; +MODULE_DEVICE_TABLE(acpi, processor_device_ids); + +static struct acpi_driver xen_acpi_processor_driver = { + .name = "processor", + .class = ACPI_PROCESSOR_CLASS, + .ids = processor_device_ids, + .ops = { + .add = xen_acpi_processor_add, + .remove = xen_acpi_processor_remove, + }, +}; + +static int __init xen_acpi_processor_init(void) +{ + int result = 0; + + if (!xen_initial_domain()) + return -ENODEV; + + /* unregister the stub which only used to reserve driver space */ + xen_stub_processor_exit(); + + result = acpi_bus_register_driver(&xen_acpi_processor_driver); + if (result < 0) { + xen_stub_processor_init(); + return result; + } + + acpi_processor_install_hotplug_notify(); + return 0; +} + +static void __exit xen_acpi_processor_exit(void) +{ + if (!xen_initial_domain()) + return; + + acpi_processor_uninstall_hotplug_notify(); + + acpi_bus_unregister_driver(&xen_acpi_processor_driver); + + /* + * stub reserve space again to prevent any chance of native + * driver loading. + */ + xen_stub_processor_init(); + return; +} + +module_init(xen_acpi_processor_init); +module_exit(xen_acpi_processor_exit); +ACPI_MODULE_NAME("xen-acpi-cpuhotplug"); +MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>"); +MODULE_DESCRIPTION("Xen Hotplug CPU Driver"); +MODULE_LICENSE("GPL"); |