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>

3 files changed, 3 insertions, 10 deletions

diff --git a/include/acpi/acpi_io.h b/include/acpi/acpi_io.h
index 2be858018c7f..444671e9c65d 100644
--- a/include/acpi/acpi_io.h
+++ b/include/acpi/acpi_io.h
@@ -9,6 +9,9 @@ static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys,
        return ioremap_cache(phys, size);
 }
 
+void __iomem *__init_refok
+acpi_os_map_iomem(acpi_physical_address phys, acpi_size size);
+void __ref acpi_os_unmap_iomem(void __iomem *virt, acpi_size size);
 void __iomem *acpi_os_get_iomem(acpi_physical_address phys, unsigned int size);
 
 int acpi_os_map_generic_address(struct acpi_generic_address *addr);
diff --git a/include/acpi/platform/aclinux.h b/include/acpi/platform/aclinux.h
index e70012956db3..cd1f052d55bb 100644
--- a/include/acpi/platform/aclinux.h
+++ b/include/acpi/platform/aclinux.h
@@ -128,8 +128,6 @@
 #define ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_acquire_object
 #define ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_thread_id
 #define ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_create_lock
-#define ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_map_memory
-#define ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_unmap_memory
 
 /*
  * OSL interfaces used by debugger/disassembler
@@ -163,10 +161,6 @@
 #define __init
 #endif
 
-#ifndef __iomem
-#define __iomem
-#endif
-
 /* Host-dependent types and defines for user-space ACPICA */
 
 #define ACPI_FLUSH_CPU_CACHE()
diff --git a/include/acpi/platform/aclinuxex.h b/include/acpi/platform/aclinuxex.h
index cce0723d05a9..191e741cfa0e 100644
--- a/include/acpi/platform/aclinuxex.h
+++ b/include/acpi/platform/aclinuxex.h
@@ -102,10 +102,6 @@ static inline acpi_thread_id acpi_os_get_thread_id(void)
 		lock ? AE_OK : AE_NO_MEMORY; \
 	})
 
-void __iomem *acpi_os_map_memory(acpi_physical_address where, acpi_size length);
-
-void acpi_os_unmap_memory(void __iomem * logical_address, acpi_size size);
-
 /*
  * OSL interfaces added by Linux
  */