ACPICA: avoid "Info: mapping multiple BARs. Your kernel is fine."

Ensure that memory mappings created for operation regions
do not cross page boundaries.  Crossing a page boundary
while mapping regions can cause warnings if the pages have different attributes.

Such regions are probably BIOS bugs, and this is the workaround.

http://bugzilla.kernel.org/show_bug.cgi?id=14445

[Kernel summit hacking hour]

Signed-off-by: Bob Moore <robert.moore@intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/acpi/acpica/acconfig.h b/drivers/acpi/acpica/acconfig.h
index 8e679ef..a4471e3 100644 (file)
--- a/drivers/acpi/acpica/acconfig.h
+++ b/drivers/acpi/acpica/acconfig.h
@@ -103,9 +103,9 @@
 
 #define ACPI_MAX_REFERENCE_COUNT        0x1000
 
-/* Size of cached memory mapping for system memory operation region */
+/* Default page size for use in mapping memory for operation regions */
 
-#define ACPI_SYSMEM_REGION_WINDOW_SIZE  4096
+#define ACPI_DEFAULT_PAGE_SIZE          4096   /* Must be power of 2 */
 
 /* owner_id tracking. 8 entries allows for 255 owner_ids */
 

diff --git a/drivers/acpi/acpica/exregion.c b/drivers/acpi/acpica/exregion.c
index 3a54b73..2bd83ac 100644 (file)
--- a/drivers/acpi/acpica/exregion.c
+++ b/drivers/acpi/acpica/exregion.c
@@ -77,7 +77,8 @@ acpi_ex_system_memory_space_handler(u32 function,
        void *logical_addr_ptr = NULL;
        struct acpi_mem_space_context *mem_info = region_context;
        u32 length;
-       acpi_size window_size;
+       acpi_size map_length;
+       acpi_size page_boundary_map_length;
 #ifdef ACPI_MISALIGNMENT_NOT_SUPPORTED
        u32 remainder;
 #endif
@@ -144,25 +145,39 @@ acpi_ex_system_memory_space_handler(u32 function,
                }
 
                /*
-                * Don't attempt to map memory beyond the end of the region, and
-                * constrain the maximum mapping size to something reasonable.
+                * Attempt to map from the requested address to the end of the region.
+                * However, we will never map more than one page, nor will we cross
+                * a page boundary.
                 */
-               window_size = (acpi_size)
+               map_length = (acpi_size)
                    ((mem_info->address + mem_info->length) - address);
 
-               if (window_size > ACPI_SYSMEM_REGION_WINDOW_SIZE) {
-                       window_size = ACPI_SYSMEM_REGION_WINDOW_SIZE;
+               /*
+                * If mapping the entire remaining portion of the region will cross
+                * a page boundary, just map up to the page boundary, do not cross.
+                * On some systems, crossing a page boundary while mapping regions
+                * can cause warnings if the pages have different attributes
+                * due to resource management
+                */
+               page_boundary_map_length =
+                   ACPI_ROUND_UP(address, ACPI_DEFAULT_PAGE_SIZE) - address;
+
+               if (!page_boundary_map_length) {
+                       page_boundary_map_length = ACPI_DEFAULT_PAGE_SIZE;
+               }
+
+               if (map_length > page_boundary_map_length) {
+                       map_length = page_boundary_map_length;
                }
 
                /* Create a new mapping starting at the address given */
 
-               mem_info->mapped_logical_address =
-                       acpi_os_map_memory((acpi_physical_address) address, window_size);
+               mem_info->mapped_logical_address = acpi_os_map_memory((acpi_physical_address) address, map_length);
                if (!mem_info->mapped_logical_address) {
                        ACPI_ERROR((AE_INFO,
                                    "Could not map memory at %8.8X%8.8X, size %X",
                                    ACPI_FORMAT_NATIVE_UINT(address),
-                                   (u32) window_size));
+                                   (u32) map_length));
                        mem_info->mapped_length = 0;
                        return_ACPI_STATUS(AE_NO_MEMORY);
                }
@@ -170,7 +185,7 @@ acpi_ex_system_memory_space_handler(u32 function,
                /* Save the physical address and mapping size */
 
                mem_info->mapped_physical_address = address;
-               mem_info->mapped_length = window_size;
+               mem_info->mapped_length = map_length;
        }
 
        /*