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>
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 9aeae41e..147bc1b 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -355,7 +355,7 @@
}
void __iomem *__init_refok
-acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
+acpi_os_map_iomem(acpi_physical_address phys, acpi_size size)
{
struct acpi_ioremap *map;
void __iomem *virt;
@@ -401,10 +401,17 @@
list_add_tail_rcu(&map->list, &acpi_ioremaps);
- out:
+out:
mutex_unlock(&acpi_ioremap_lock);
return map->virt + (phys - map->phys);
}
+EXPORT_SYMBOL_GPL(acpi_os_map_iomem);
+
+void *__init_refok
+acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
+{
+ return (void *)acpi_os_map_iomem(phys, size);
+}
EXPORT_SYMBOL_GPL(acpi_os_map_memory);
static void acpi_os_drop_map_ref(struct acpi_ioremap *map)
@@ -422,7 +429,7 @@
}
}
-void __ref acpi_os_unmap_memory(void __iomem *virt, acpi_size size)
+void __ref acpi_os_unmap_iomem(void __iomem *virt, acpi_size size)
{
struct acpi_ioremap *map;
@@ -443,6 +450,12 @@
acpi_os_map_cleanup(map);
}
+EXPORT_SYMBOL_GPL(acpi_os_unmap_iomem);
+
+void __ref acpi_os_unmap_memory(void *virt, acpi_size size)
+{
+ return acpi_os_unmap_iomem((void __iomem *)virt, size);
+}
EXPORT_SYMBOL_GPL(acpi_os_unmap_memory);
void __init early_acpi_os_unmap_memory(void __iomem *virt, acpi_size size)
@@ -464,7 +477,7 @@
if (!addr || !gas->bit_width)
return -EINVAL;
- virt = acpi_os_map_memory(addr, gas->bit_width / 8);
+ virt = acpi_os_map_iomem(addr, gas->bit_width / 8);
if (!virt)
return -EIO;
