From: Bob Moore <robert.moore@xxxxxxxxx> 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@xxxxxxxxx> Acked-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx> Signed-off-by: Lin Ming <ming.m.lin@xxxxxxxxx> Signed-off-by: Len Brown <len.brown@xxxxxxxxx> --- drivers/acpi/acpica/acconfig.h | 4 ++-- drivers/acpi/acpica/exregion.c | 35 +++++++++++++++++++++++++---------- 2 files changed, 27 insertions(+), 12 deletions(-) diff --git a/drivers/acpi/acpica/acconfig.h b/drivers/acpi/acpica/acconfig.h index 8e679ef..a4471e3 100644 --- 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 --- 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; } /* -- 1.6.0.6 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
