linux/drivers/xen/xen-acpi-memhotplug.c
Liu Jinsong 484400ffbf xen/acpi: xen memory hotplug minor updates
Dan Carpenter found current xen memory hotplug logic
has potential issue: at func acpi_memory_get_device()
*mem_device = acpi_driver_data(device);
while the device may be NULL and then dereference.

At native side, Rafael recently updated acpi_memory_get_device(),
dropping acpi_bus_add, adding lock, and avoiding above issue.

This patch updates xen memory hotplug logic accordingly, removing
redundant logic, adding lock, and avoiding dereference.

Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-02-25 07:44:21 -05:00

484 lines
12 KiB
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.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/acpi.h>
#include <acpi/acpi_drivers.h>
#include <xen/acpi.h>
#include <xen/interface/platform.h>
#include <asm/xen/hypercall.h>
#define PREFIX "ACPI:xen_memory_hotplug:"
struct acpi_memory_info {
struct list_head list;
u64 start_addr; /* Memory Range start physical addr */
u64 length; /* Memory Range length */
unsigned short caching; /* memory cache attribute */
unsigned short write_protect; /* memory read/write attribute */
/* copied from buffer getting from _CRS */
unsigned int enabled:1;
};
struct acpi_memory_device {
struct acpi_device *device;
struct list_head res_list;
};
static bool acpi_hotmem_initialized __read_mostly;
static int xen_hotadd_memory(int pxm, struct acpi_memory_info *info)
{
int rc;
struct xen_platform_op op;
op.cmd = XENPF_mem_hotadd;
op.u.mem_add.spfn = info->start_addr >> PAGE_SHIFT;
op.u.mem_add.epfn = (info->start_addr + info->length) >> PAGE_SHIFT;
op.u.mem_add.pxm = pxm;
rc = HYPERVISOR_dom0_op(&op);
if (rc)
pr_err(PREFIX "Xen Hotplug Memory Add failed on "
"0x%lx -> 0x%lx, _PXM: %d, error: %d\n",
(unsigned long)info->start_addr,
(unsigned long)(info->start_addr + info->length),
pxm, rc);
return rc;
}
static int xen_acpi_memory_enable_device(struct acpi_memory_device *mem_device)
{
int pxm, result;
int num_enabled = 0;
struct acpi_memory_info *info;
if (!mem_device)
return -EINVAL;
pxm = xen_acpi_get_pxm(mem_device->device->handle);
if (pxm < 0)
return pxm;
list_for_each_entry(info, &mem_device->res_list, list) {
if (info->enabled) { /* just sanity check...*/
num_enabled++;
continue;
}
if (!info->length)
continue;
result = xen_hotadd_memory(pxm, info);
if (result)
continue;
info->enabled = 1;
num_enabled++;
}
if (!num_enabled)
return -ENODEV;
return 0;
}
static acpi_status
acpi_memory_get_resource(struct acpi_resource *resource, void *context)
{
struct acpi_memory_device *mem_device = context;
struct acpi_resource_address64 address64;
struct acpi_memory_info *info, *new;
acpi_status status;
status = acpi_resource_to_address64(resource, &address64);
if (ACPI_FAILURE(status) ||
(address64.resource_type != ACPI_MEMORY_RANGE))
return AE_OK;
list_for_each_entry(info, &mem_device->res_list, list) {
if ((info->caching == address64.info.mem.caching) &&
(info->write_protect == address64.info.mem.write_protect) &&
(info->start_addr + info->length == address64.minimum)) {
info->length += address64.address_length;
return AE_OK;
}
}
new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
if (!new)
return AE_ERROR;
INIT_LIST_HEAD(&new->list);
new->caching = address64.info.mem.caching;
new->write_protect = address64.info.mem.write_protect;
new->start_addr = address64.minimum;
new->length = address64.address_length;
list_add_tail(&new->list, &mem_device->res_list);
return AE_OK;
}
static int
acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
{
acpi_status status;
struct acpi_memory_info *info, *n;
if (!list_empty(&mem_device->res_list))
return 0;
status = acpi_walk_resources(mem_device->device->handle,
METHOD_NAME__CRS, acpi_memory_get_resource, mem_device);
if (ACPI_FAILURE(status)) {
list_for_each_entry_safe(info, n, &mem_device->res_list, list)
kfree(info);
INIT_LIST_HEAD(&mem_device->res_list);
return -EINVAL;
}
return 0;
}
static int acpi_memory_get_device(acpi_handle handle,
struct acpi_memory_device **mem_device)
{
struct acpi_device *device = NULL;
int result = 0;
acpi_scan_lock_acquire();
acpi_bus_get_device(handle, &device);
if (device)
goto end;
/*
* Now add the notified device. This creates the acpi_device
* and invokes .add function
*/
result = acpi_bus_scan(handle);
if (result) {
pr_warn(PREFIX "ACPI namespace scan failed\n");
result = -EINVAL;
goto out;
}
result = acpi_bus_get_device(handle, &device);
if (result) {
pr_warn(PREFIX "Missing device object\n");
result = -EINVAL;
goto out;
}
end:
*mem_device = acpi_driver_data(device);
if (!(*mem_device)) {
pr_err(PREFIX "driver data not found\n");
result = -ENODEV;
goto out;
}
out:
acpi_scan_lock_release();
return result;
}
static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
{
unsigned long long current_status;
/* Get device present/absent information from the _STA */
if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
"_STA", NULL, &current_status)))
return -ENODEV;
/*
* Check for device status. Device should be
* present/enabled/functioning.
*/
if (!((current_status & ACPI_STA_DEVICE_PRESENT)
&& (current_status & ACPI_STA_DEVICE_ENABLED)
&& (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
return -ENODEV;
return 0;
}
static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
{
pr_debug(PREFIX "Xen does not support memory hotremove\n");
return -ENOSYS;
}
static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
{
struct acpi_memory_device *mem_device;
struct acpi_device *device;
u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
switch (event) {
case ACPI_NOTIFY_BUS_CHECK:
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"\nReceived BUS CHECK notification for device\n"));
/* Fall Through */
case ACPI_NOTIFY_DEVICE_CHECK:
if (event == ACPI_NOTIFY_DEVICE_CHECK)
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"\nReceived DEVICE CHECK notification for device\n"));
if (acpi_memory_get_device(handle, &mem_device)) {
pr_err(PREFIX "Cannot find driver data\n");
break;
}
ost_code = ACPI_OST_SC_SUCCESS;
break;
case ACPI_NOTIFY_EJECT_REQUEST:
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"\nReceived EJECT REQUEST notification for device\n"));
acpi_scan_lock_acquire();
if (acpi_bus_get_device(handle, &device)) {
acpi_scan_lock_release();
pr_err(PREFIX "Device doesn't exist\n");
break;
}
mem_device = acpi_driver_data(device);
if (!mem_device) {
acpi_scan_lock_release();
pr_err(PREFIX "Driver Data is NULL\n");
break;
}
/*
* TBD: implement acpi_memory_disable_device and invoke
* acpi_bus_remove if Xen support hotremove in the future
*/
acpi_memory_disable_device(mem_device);
acpi_scan_lock_release();
break;
default:
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Unsupported event [0x%x]\n", event));
/* non-hotplug event; possibly handled by other handler */
return;
}
(void) acpi_evaluate_hotplug_ost(handle, event, ost_code, NULL);
return;
}
static int xen_acpi_memory_device_add(struct acpi_device *device)
{
int result;
struct acpi_memory_device *mem_device = NULL;
if (!device)
return -EINVAL;
mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
if (!mem_device)
return -ENOMEM;
INIT_LIST_HEAD(&mem_device->res_list);
mem_device->device = device;
sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
device->driver_data = mem_device;
/* Get the range from the _CRS */
result = acpi_memory_get_device_resources(mem_device);
if (result) {
kfree(mem_device);
return result;
}
/*
* For booting existed memory devices, early boot code has recognized
* memory area by EFI/E820. If DSDT shows these memory devices on boot,
* hotplug is not necessary for them.
* For hot-added memory devices during runtime, it need hypercall to
* Xen hypervisor to add memory.
*/
if (!acpi_hotmem_initialized)
return 0;
if (!acpi_memory_check_device(mem_device))
result = xen_acpi_memory_enable_device(mem_device);
return result;
}
static int xen_acpi_memory_device_remove(struct acpi_device *device)
{
struct acpi_memory_device *mem_device = NULL;
if (!device || !acpi_driver_data(device))
return -EINVAL;
mem_device = acpi_driver_data(device);
kfree(mem_device);
return 0;
}
/*
* Helper function to check for memory device
*/
static acpi_status is_memory_device(acpi_handle handle)
{
char *hardware_id;
acpi_status status;
struct acpi_device_info *info;
status = acpi_get_object_info(handle, &info);
if (ACPI_FAILURE(status))
return status;
if (!(info->valid & ACPI_VALID_HID)) {
kfree(info);
return AE_ERROR;
}
hardware_id = info->hardware_id.string;
if ((hardware_id == NULL) ||
(strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
status = AE_ERROR;
kfree(info);
return status;
}
static acpi_status
acpi_memory_register_notify_handler(acpi_handle handle,
u32 level, void *ctxt, void **retv)
{
acpi_status status;
status = is_memory_device(handle);
if (ACPI_FAILURE(status))
return AE_OK; /* continue */
status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
acpi_memory_device_notify, NULL);
/* continue */
return AE_OK;
}
static acpi_status
acpi_memory_deregister_notify_handler(acpi_handle handle,
u32 level, void *ctxt, void **retv)
{
acpi_status status;
status = is_memory_device(handle);
if (ACPI_FAILURE(status))
return AE_OK; /* continue */
status = acpi_remove_notify_handler(handle,
ACPI_SYSTEM_NOTIFY,
acpi_memory_device_notify);
return AE_OK; /* continue */
}
static const struct acpi_device_id memory_device_ids[] = {
{ACPI_MEMORY_DEVICE_HID, 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, memory_device_ids);
static struct acpi_driver xen_acpi_memory_device_driver = {
.name = "acpi_memhotplug",
.class = ACPI_MEMORY_DEVICE_CLASS,
.ids = memory_device_ids,
.ops = {
.add = xen_acpi_memory_device_add,
.remove = xen_acpi_memory_device_remove,
},
};
static int __init xen_acpi_memory_device_init(void)
{
int result;
acpi_status status;
if (!xen_initial_domain())
return -ENODEV;
/* unregister the stub which only used to reserve driver space */
xen_stub_memory_device_exit();
result = acpi_bus_register_driver(&xen_acpi_memory_device_driver);
if (result < 0) {
xen_stub_memory_device_init();
return -ENODEV;
}
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX,
acpi_memory_register_notify_handler,
NULL, NULL, NULL);
if (ACPI_FAILURE(status)) {
pr_warn(PREFIX "walk_namespace failed\n");
acpi_bus_unregister_driver(&xen_acpi_memory_device_driver);
xen_stub_memory_device_init();
return -ENODEV;
}
acpi_hotmem_initialized = true;
return 0;
}
static void __exit xen_acpi_memory_device_exit(void)
{
acpi_status status;
if (!xen_initial_domain())
return;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX,
acpi_memory_deregister_notify_handler,
NULL, NULL, NULL);
if (ACPI_FAILURE(status))
pr_warn(PREFIX "walk_namespace failed\n");
acpi_bus_unregister_driver(&xen_acpi_memory_device_driver);
/*
* stub reserve space again to prevent any chance of native
* driver loading.
*/
xen_stub_memory_device_init();
return;
}
module_init(xen_acpi_memory_device_init);
module_exit(xen_acpi_memory_device_exit);
ACPI_MODULE_NAME("xen-acpi-memhotplug");
MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
MODULE_DESCRIPTION("Xen Hotplug Mem Driver");
MODULE_LICENSE("GPL");