- 根目录:
- drivers
- xen
- xen-acpi-cpuhotplug.c
/*
* Copyright (C) 2012 Intel Corporation
* Author: Liu Jinsong <jinsong.liu@intel.com>
* Author: Jiang Yunhong <yunhong.jiang@intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for more
* details.
*/
#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;
pr = acpi_driver_data(device);
if (!pr) {
pr_err(PREFIX "Cannot find driver data\n");
return -EINVAL;
}
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 ((int)pr->id < 0)
/* 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_dom0_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 ((int)pr->id < 0)
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_hotplug_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");