diff options
| -rw-r--r-- | drivers/acpi/acpica/tbxfroot.c | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/drivers/acpi/acpica/tbxfroot.c b/drivers/acpi/acpica/tbxfroot.c index ede2745838c8..f1c2ab0a4561 100644 --- a/drivers/acpi/acpica/tbxfroot.c +++ b/drivers/acpi/acpica/tbxfroot.c @@ -114,6 +114,7 @@ acpi_find_root_pointer(acpi_physical_address *table_address) u8 *table_ptr; u8 *mem_rover; u32 physical_address; + u32 ebda_window_size; ACPI_FUNCTION_TRACE(acpi_find_root_pointer); @@ -145,24 +146,31 @@ acpi_find_root_pointer(acpi_physical_address *table_address) */ if (physical_address > 0x400 && physical_address < 0xA0000) { /* - * 1b) Search EBDA paragraphs (EBDA is required to be a - * minimum of 1K length) + * Calculate the scan window size + * The EBDA is not guaranteed to be larger than a ki_b and in case + * that it is smaller, the scanning function would leave the low + * memory and continue to the VGA range. + */ + ebda_window_size = ACPI_MIN(ACPI_EBDA_WINDOW_SIZE, + 0xA0000 - physical_address); + + /* + * 1b) Search EBDA paragraphs */ table_ptr = acpi_os_map_memory((acpi_physical_address) physical_address, - ACPI_EBDA_WINDOW_SIZE); + ebda_window_size); if (!table_ptr) { ACPI_ERROR((AE_INFO, "Could not map memory at 0x%8.8X for length %u", - physical_address, ACPI_EBDA_WINDOW_SIZE)); + physical_address, ebda_window_size)); return_ACPI_STATUS(AE_NO_MEMORY); } mem_rover = - acpi_tb_scan_memory_for_rsdp(table_ptr, - ACPI_EBDA_WINDOW_SIZE); - acpi_os_unmap_memory(table_ptr, ACPI_EBDA_WINDOW_SIZE); + acpi_tb_scan_memory_for_rsdp(table_ptr, ebda_window_size); + acpi_os_unmap_memory(table_ptr, ebda_window_size); if (mem_rover) { |