linux-stable/drivers/acpi/nvs.c
Lv Zheng a238317ce8 ACPI: Clean up acpi_os_map/unmap_memory() to eliminate __iomem.
ACPICA doesn't include protections around address space checking, Linux
build tests always complain increased sparse warnings around ACPICA
internal acpi_os_map/unmap_memory() invocations.  This patch tries to fix
this issue permanently.

There are 2 choices left for us to solve this issue:
 1. Add __iomem address space awareness into ACPICA.
 2. Remove sparse checker of __iomem from ACPICA source code.

This patch chooses solution 2, because:
 1.  Most of the acpi_os_map/unmap_memory() invocations are used for ACPICA.
     table mappings, which in fact are not IO addresses.
 2.  The only IO addresses usage is for "system memory space" mapping code in:
      drivers/acpi/acpica/exregion.c
      drivers/acpi/acpica/evrgnini.c
      drivers/acpi/acpica/exregion.c
    The mapped address is accessed in the handler of "system memory space"
    - acpi_ex_system_memory_space_handler().  This function in fact can be
    changed to invoke acpi_os_read/write_memory() so that __iomem can
    always be type-casted in the OSL layer.

According to the above investigation, we drew the following conclusion:
It is not a good idea to introduce __iomem address space awareness into
ACPICA mostly in order to protect non-IO addresses.

We can simply remove __iomem for acpi_os_map/unmap_memory() to remove
__iomem checker for ACPICA code. Then we need to enforce external usages
to invoke other APIs that are aware of __iomem address space.
The external usages are:
 drivers/acpi/apei/einj.c
 drivers/acpi/acpi_extlog.c
 drivers/char/tpm/tpm_acpi.c
 drivers/acpi/nvs.c

This patch thus performs cleanups in this way:
 1. Add acpi_os_map/unmap_iomem() to be invoked by non-ACPICA code.
 2. Remove __iomem from acpi_os_map/unmap_memory().

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-27 18:13:08 +02:00

212 lines
4.6 KiB
C

/*
* nvs.c - Routines for saving and restoring ACPI NVS memory region
*
* Copyright (C) 2008-2011 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
*
* This file is released under the GPLv2.
*/
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include "internal.h"
/* ACPI NVS regions, APEI may use it */
struct nvs_region {
__u64 phys_start;
__u64 size;
struct list_head node;
};
static LIST_HEAD(nvs_region_list);
#ifdef CONFIG_ACPI_SLEEP
static int suspend_nvs_register(unsigned long start, unsigned long size);
#else
static inline int suspend_nvs_register(unsigned long a, unsigned long b)
{
return 0;
}
#endif
int acpi_nvs_register(__u64 start, __u64 size)
{
struct nvs_region *region;
region = kmalloc(sizeof(*region), GFP_KERNEL);
if (!region)
return -ENOMEM;
region->phys_start = start;
region->size = size;
list_add_tail(&region->node, &nvs_region_list);
return suspend_nvs_register(start, size);
}
int acpi_nvs_for_each_region(int (*func)(__u64 start, __u64 size, void *data),
void *data)
{
int rc;
struct nvs_region *region;
list_for_each_entry(region, &nvs_region_list, node) {
rc = func(region->phys_start, region->size, data);
if (rc)
return rc;
}
return 0;
}
#ifdef CONFIG_ACPI_SLEEP
/*
* Platforms, like ACPI, may want us to save some memory used by them during
* suspend and to restore the contents of this memory during the subsequent
* resume. The code below implements a mechanism allowing us to do that.
*/
struct nvs_page {
unsigned long phys_start;
unsigned int size;
void *kaddr;
void *data;
bool unmap;
struct list_head node;
};
static LIST_HEAD(nvs_list);
/**
* suspend_nvs_register - register platform NVS memory region to save
* @start - physical address of the region
* @size - size of the region
*
* The NVS region need not be page-aligned (both ends) and we arrange
* things so that the data from page-aligned addresses in this region will
* be copied into separate RAM pages.
*/
static int suspend_nvs_register(unsigned long start, unsigned long size)
{
struct nvs_page *entry, *next;
pr_info("PM: Registering ACPI NVS region [mem %#010lx-%#010lx] (%ld bytes)\n",
start, start + size - 1, size);
while (size > 0) {
unsigned int nr_bytes;
entry = kzalloc(sizeof(struct nvs_page), GFP_KERNEL);
if (!entry)
goto Error;
list_add_tail(&entry->node, &nvs_list);
entry->phys_start = start;
nr_bytes = PAGE_SIZE - (start & ~PAGE_MASK);
entry->size = (size < nr_bytes) ? size : nr_bytes;
start += entry->size;
size -= entry->size;
}
return 0;
Error:
list_for_each_entry_safe(entry, next, &nvs_list, node) {
list_del(&entry->node);
kfree(entry);
}
return -ENOMEM;
}
/**
* suspend_nvs_free - free data pages allocated for saving NVS regions
*/
void suspend_nvs_free(void)
{
struct nvs_page *entry;
list_for_each_entry(entry, &nvs_list, node)
if (entry->data) {
free_page((unsigned long)entry->data);
entry->data = NULL;
if (entry->kaddr) {
if (entry->unmap) {
iounmap(entry->kaddr);
entry->unmap = false;
} else {
acpi_os_unmap_iomem(entry->kaddr,
entry->size);
}
entry->kaddr = NULL;
}
}
}
/**
* suspend_nvs_alloc - allocate memory necessary for saving NVS regions
*/
int suspend_nvs_alloc(void)
{
struct nvs_page *entry;
list_for_each_entry(entry, &nvs_list, node) {
entry->data = (void *)__get_free_page(GFP_KERNEL);
if (!entry->data) {
suspend_nvs_free();
return -ENOMEM;
}
}
return 0;
}
/**
* suspend_nvs_save - save NVS memory regions
*/
int suspend_nvs_save(void)
{
struct nvs_page *entry;
printk(KERN_INFO "PM: Saving platform NVS memory\n");
list_for_each_entry(entry, &nvs_list, node)
if (entry->data) {
unsigned long phys = entry->phys_start;
unsigned int size = entry->size;
entry->kaddr = acpi_os_get_iomem(phys, size);
if (!entry->kaddr) {
entry->kaddr = acpi_os_ioremap(phys, size);
entry->unmap = !!entry->kaddr;
}
if (!entry->kaddr) {
suspend_nvs_free();
return -ENOMEM;
}
memcpy(entry->data, entry->kaddr, entry->size);
}
return 0;
}
/**
* suspend_nvs_restore - restore NVS memory regions
*
* This function is going to be called with interrupts disabled, so it
* cannot iounmap the virtual addresses used to access the NVS region.
*/
void suspend_nvs_restore(void)
{
struct nvs_page *entry;
printk(KERN_INFO "PM: Restoring platform NVS memory\n");
list_for_each_entry(entry, &nvs_list, node)
if (entry->data)
memcpy(entry->kaddr, entry->data, entry->size);
}
#endif