linux/drivers/xen/xen-acpi-cpuhotplug.c

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/*
* 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;
}
Features: - Xen ACPI memory and CPU hotplug drivers - allowing Xen hypervisor to be aware of new CPU and new DIMMs - Cleanups Bug-fixes: - Fixes a long-standing bug in the PV spinlock wherein we did not kick VCPUs that were in a tight loop. - Fixes in the error paths for the event channel machinery. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (GNU/Linux) iQEcBAABAgAGBQJRJS1kAAoJEFjIrFwIi8fJj2YIAMO3/LVUZyojX/d8U9pqrCly lFfEF2UVjcxHJSj0ZFNXt1o3fnYP1SLRlT9u7ZLDjXf6Lmxmw6/C3Haw2wp3DfGq yUR0G/X9CPTBEgMYDdX7bjeTjyURvZcUaFwr+qodaaeL3uXx2pW6621Sc6jRKuia yAFVZMAKeaRrvUUIXjKHtlpRp9LKFdSztShMtYqmFvxEwrJPq2b37caKruoUCa6o X/YO0fvE9QtYD/pG0jsghFmLh/mcr+n9IFMCUXo1Yc9FdQBExtKzABDS5jdpuFND 4aMDE3dqUmHmpbaQhRE7SdblvpyrGdQXL6FSTjvwBgISfLo847CrnRKRgPp0YeA= =LQeU -----END PGP SIGNATURE----- Merge tag 'stable/for-linus-3.9-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen Pull Xen update from Konrad Rzeszutek Wilk: "This has two new ACPI drivers for Xen - a physical CPU offline/online and a memory hotplug. The way this works is that ACPI kicks the drivers and they make the appropiate hypercall to the hypervisor to tell it that there is a new CPU or memory. There also some changes to the Xen ARM ABIs and couple of fixes. One particularly nasty bug in the Xen PV spinlock code was fixed by Stefan Bader - and has been there since the 2.6.32! Features: - Xen ACPI memory and CPU hotplug drivers - allowing Xen hypervisor to be aware of new CPU and new DIMMs - Cleanups Bug-fixes: - Fixes a long-standing bug in the PV spinlock wherein we did not kick VCPUs that were in a tight loop. - Fixes in the error paths for the event channel machinery" Fix up a few semantic conflicts with the ACPI interface changes in drivers/xen/xen-acpi-{cpu,mem}hotplug.c. * tag 'stable/for-linus-3.9-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: xen: event channel arrays are xen_ulong_t and not unsigned long xen: Send spinlock IPI to all waiters xen: introduce xen_remap, use it instead of ioremap xen: close evtchn port if binding to irq fails xen-evtchn: correct comment and error output xen/tmem: Add missing %s in the printk statement. xen/acpi: move xen_acpi_get_pxm under CONFIG_XEN_DOM0 xen/acpi: ACPI cpu hotplug xen/acpi: Move xen_acpi_get_pxm to Xen's acpi.h xen/stub: driver for CPU hotplug xen/acpi: ACPI memory hotplug xen/stub: driver for memory hotplug xen: implement updated XENMEM_add_to_physmap_range ABI xen/smp: Move the common CPU init code a bit to prep for PVH patch.
2013-02-25 00:06:13 +00:00
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 / scan: Add acpi_device objects for all device nodes in the namespace Modify the ACPI namespace scanning code to register a struct acpi_device object for every namespace node representing a device, processor and so on, even if the device represented by that namespace node is reported to be not present and not functional by _STA. There are multiple reasons to do that. First of all, it avoids quite a lot of overhead when struct acpi_device objects are deleted every time acpi_bus_trim() is run and then added again by a subsequent acpi_bus_scan() for the same scope, although the namespace objects they correspond to stay in memory all the time (which always is the case on a vast majority of systems). Second, it will allow user space to see that there are namespace nodes representing devices that are not present at the moment and may be added to the system. It will also allow user space to evaluate _SUN for those nodes to check what physical slots the "missing" devices may be put into and it will make sense to add a sysfs attribute for _STA evaluation after this change (that will be useful for thermal management on some systems). Next, it will help to consolidate the ACPI hotplug handling among subsystems by making it possible to store hotplug-related information in struct acpi_device objects in a standard common way. Finally, it will help to avoid a race condition related to the deletion of ACPI namespace nodes. Namely, namespace nodes may be deleted as a result of a table unload triggered by _EJ0 or _DCK. If a hotplug notification for one of those nodes is triggered right before the deletion and it executes a hotplug callback via acpi_hotplug_execute(), the ACPI handle passed to that callback may be stale when the callback actually runs. One way to work around that is to always pass struct acpi_device pointers to hotplug callbacks after doing a get_device() on the objects in question which eliminates the use-after-free possibility (the ACPI handles in those objects are invalidated by acpi_scan_drop_device(), so they will trigger ACPICA errors on attempts to use them). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-11-22 20:54:37 +00:00
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;
}
ACPI / scan: Add acpi_device objects for all device nodes in the namespace Modify the ACPI namespace scanning code to register a struct acpi_device object for every namespace node representing a device, processor and so on, even if the device represented by that namespace node is reported to be not present and not functional by _STA. There are multiple reasons to do that. First of all, it avoids quite a lot of overhead when struct acpi_device objects are deleted every time acpi_bus_trim() is run and then added again by a subsequent acpi_bus_scan() for the same scope, although the namespace objects they correspond to stay in memory all the time (which always is the case on a vast majority of systems). Second, it will allow user space to see that there are namespace nodes representing devices that are not present at the moment and may be added to the system. It will also allow user space to evaluate _SUN for those nodes to check what physical slots the "missing" devices may be put into and it will make sense to add a sysfs attribute for _STA evaluation after this change (that will be useful for thermal management on some systems). Next, it will help to consolidate the ACPI hotplug handling among subsystems by making it possible to store hotplug-related information in struct acpi_device objects in a standard common way. Finally, it will help to avoid a race condition related to the deletion of ACPI namespace nodes. Namely, namespace nodes may be deleted as a result of a table unload triggered by _EJ0 or _DCK. If a hotplug notification for one of those nodes is triggered right before the deletion and it executes a hotplug callback via acpi_hotplug_execute(), the ACPI handle passed to that callback may be stale when the callback actually runs. One way to work around that is to always pass struct acpi_device pointers to hotplug callbacks after doing a get_device() on the objects in question which eliminates the use-after-free possibility (the ACPI handles in those objects are invalidated by acpi_scan_drop_device(), so they will trigger ACPICA errors on attempts to use them). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2013-11-22 20:54:37 +00:00
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");