1 files changed, 78 insertions, 18 deletions

diff --git a/drivers/acpi/acpica/exconfig.c b/drivers/acpi/acpica/exconfig.c
index 0731fd6bad63..eca6f63a53fd 100644
--- a/drivers/acpi/acpica/exconfig.c
+++ b/drivers/acpi/acpica/exconfig.c
@@ -47,6 +47,7 @@
 #include "acnamesp.h"
 #include "actables.h"
 #include "acdispat.h"
+#include "acevents.h"
 
 #define _COMPONENT          ACPI_EXECUTER
 ACPI_MODULE_NAME("exconfig")
@@ -57,6 +58,10 @@ acpi_ex_add_table(u32 table_index,
                   struct acpi_namespace_node *parent_node,
                   union acpi_operand_object **ddb_handle);
 
+static acpi_status
+acpi_ex_region_read(union acpi_operand_object *obj_desc,
+                    u32 length, u8 *buffer);
+
 /*******************************************************************************
  *
  * FUNCTION:    acpi_ex_add_table
@@ -257,6 +262,48 @@ acpi_ex_load_table_op(struct acpi_walk_state *walk_state,
 
 /*******************************************************************************
  *
+ * FUNCTION:    acpi_ex_region_read
+ *
+ * PARAMETERS:  obj_desc        - Region descriptor
+ *              Length          - Number of bytes to read
+ *              Buffer          - Pointer to where to put the data
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Read data from an operation region. The read starts from the
+ *              beginning of the region.
+ *
+ ******************************************************************************/
+
+static acpi_status
+acpi_ex_region_read(union acpi_operand_object *obj_desc, u32 length, u8 *buffer)
+{
+        acpi_status status;
+        acpi_integer value;
+        acpi_physical_address address;
+        u32 i;
+
+        address = obj_desc->region.address;
+
+        /* Bytewise reads */
+
+        for (i = 0; i < length; i++) {
+                status = acpi_ev_address_space_dispatch(obj_desc, ACPI_READ,
+                                                        address, 8, &value);
+                if (ACPI_FAILURE(status)) {
+                        return status;
+                }
+
+                *buffer = (u8)value;
+                buffer++;
+                address++;
+        }
+
+        return AE_OK;
+}
+
+/*******************************************************************************
+ *
  * FUNCTION:    acpi_ex_load_op
  *
  * PARAMETERS:  obj_desc        - Region or Buffer/Field where the table will be
@@ -317,18 +364,23 @@ acpi_ex_load_op(union acpi_operand_object *obj_desc,
                         }
                 }
 
-                /*
-                 * Map the table header and get the actual table length. The region
-                 * length is not guaranteed to be the same as the table length.
-                 */
-                table = acpi_os_map_memory(obj_desc->region.address,
-                                           sizeof(struct acpi_table_header));
+                /* Get the table header first so we can get the table length */
+
+                table = ACPI_ALLOCATE(sizeof(struct acpi_table_header));
                 if (!table) {
                         return_ACPI_STATUS(AE_NO_MEMORY);
                 }
 
+                status =
+                    acpi_ex_region_read(obj_desc,
+                                        sizeof(struct acpi_table_header),
+                                        ACPI_CAST_PTR(u8, table));
                 length = table->length;
-                acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
+                ACPI_FREE(table);
+
+                if (ACPI_FAILURE(status)) {
+                        return_ACPI_STATUS(status);
+                }
 
                 /* Must have at least an ACPI table header */
 
@@ -337,10 +389,19 @@ acpi_ex_load_op(union acpi_operand_object *obj_desc,
                 }
 
                 /*
-                 * The memory region is not guaranteed to remain stable and we must
-                 * copy the table to a local buffer. For example, the memory region
-                 * is corrupted after suspend on some machines. Dynamically loaded
-                 * tables are usually small, so this overhead is minimal.
+                 * The original implementation simply mapped the table, with no copy.
+                 * However, the memory region is not guaranteed to remain stable and
+                 * we must copy the table to a local buffer. For example, the memory
+                 * region is corrupted after suspend on some machines. Dynamically
+                 * loaded tables are usually small, so this overhead is minimal.
+                 *
+                 * The latest implementation (5/2009) does not use a mapping at all.
+                 * We use the low-level operation region interface to read the table
+                 * instead of the obvious optimization of using a direct mapping.
+                 * This maintains a consistent use of operation regions across the
+                 * entire subsystem. This is important if additional processing must
+                 * be performed in the (possibly user-installed) operation region
+                 * handler. For example, acpi_exec and ASLTS depend on this.
                  */
 
                 /* Allocate a buffer for the table */
@@ -350,17 +411,16 @@ acpi_ex_load_op(union acpi_operand_object *obj_desc,
                         return_ACPI_STATUS(AE_NO_MEMORY);
                 }
 
-                /* Map the entire table and copy it */
+                /* Read the entire table */
 
-                table = acpi_os_map_memory(obj_desc->region.address, length);
-                if (!table) {
+                status = acpi_ex_region_read(obj_desc, length,
+                                             ACPI_CAST_PTR(u8,
+                                                           table_desc.pointer));
+                if (ACPI_FAILURE(status)) {
                         ACPI_FREE(table_desc.pointer);
-                        return_ACPI_STATUS(AE_NO_MEMORY);
+                        return_ACPI_STATUS(status);
                 }
 
-                ACPI_MEMCPY(table_desc.pointer, table, length);
-                acpi_os_unmap_memory(table, length);
-
                 table_desc.address = obj_desc->region.address;
                 break;