x86: Remove BIOS data range from e820

In preparation for moving to the generic page_is_ram(), make explicit
what we expect to be reserved and not reserved.

Tested-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <20100122033004.335813103@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 18 insertions, 1 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index cdb6a8a506dd..f9b1f4e5ab74 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -650,6 +650,23 @@ static struct dmi_system_id __initdata bad_bios_dmi_table[] = {
         {}
 };
 
+static void __init trim_bios_range(void)
+{
+        /*
+         * A special case is the first 4Kb of memory;
+         * This is a BIOS owned area, not kernel ram, but generally
+         * not listed as such in the E820 table.
+         */
+        e820_update_range(0, PAGE_SIZE, E820_RAM, E820_RESERVED);
+        /*
+         * special case: Some BIOSen report the PC BIOS
+         * area (640->1Mb) as ram even though it is not.
+         * take them out.
+         */
+        e820_remove_range(BIOS_BEGIN, BIOS_END - BIOS_BEGIN, E820_RAM, 1);
+        sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+}
+
 /*
  * Determine if we were loaded by an EFI loader.  If so, then we have also been
  * passed the efi memmap, systab, etc., so we should use these data structures
@@ -813,7 +830,7 @@ void __init setup_arch(char **cmdline_p)
         insert_resource(&iomem_resource, &data_resource);
         insert_resource(&iomem_resource, &bss_resource);
 
-
+        trim_bios_range();
 #ifdef CONFIG_X86_32
         if (ppro_with_ram_bug()) {
                 e820_update_range(0x70000000ULL, 0x40000ULL, E820_RAM,