x86, boot: Support loading bzImage, boot_params and ramdisk above 4G

xloadflags bit 1 indicates that we can load the kernel and all data
structures above 4G; it is set if kernel is relocatable and 64bit.

bootloader will check if xloadflags bit 1 is set to decide if
it could load ramdisk and kernel high above 4G.

bootloader will fill value to ext_ramdisk_image/size for high 32bits
when it load ramdisk above 4G.
kernel use get_ramdisk_image/size to use ext_ramdisk_image/size to get
right positon for ramdisk.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Rob Landley <rob@landley.net>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Gokul Caushik <caushik1@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joe Millenbach <jmillenbach@gmail.com>
Link: http://lkml.kernel.org/r/1359058816-7615-26-git-send-email-yinghai@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 83b38617ff59..519f2bc4950a 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -298,12 +298,16 @@ static u64 __init get_ramdisk_image(void)
 {
         u64 ramdisk_image = boot_params.hdr.ramdisk_image;
 
+        ramdisk_image |= (u64)boot_params.ext_ramdisk_image << 32;
+
         return ramdisk_image;
 }
 static u64 __init get_ramdisk_size(void)
 {
         u64 ramdisk_size = boot_params.hdr.ramdisk_size;
 
+        ramdisk_size |= (u64)boot_params.ext_ramdisk_size << 32;
+
         return ramdisk_size;
 }