x86/64: Make BIOS call to declare our intention to enter long mode.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
xen-unstable changeset:   17051:55ae3b66b1b6e9039f13d9eec0b98864ca87ba6f
xen-unstable date:        Thu Feb 14 11:24:49 2008 +0000

diff --git a/xen/arch/x86/boot/trampoline.S b/xen/arch/x86/boot/trampoline.S
index 4687be2e5b01f3381f73c0dc930806c2bb2a0076..2656e07bc1f686af2c549b3e60557616a25b27da 100644 (file)
--- a/xen/arch/x86/boot/trampoline.S
+++ b/xen/arch/x86/boot/trampoline.S
@@ -147,6 +147,13 @@ trampoline_boot_cpu_entry:
         lidt    bootsym(rm_idt)
         sti
 
+#if defined(__x86_64__)
+        /* Declare that our target operating mode is long mode. */
+        movw    $0xec00,%ax      # declare target operating mode
+        movw    $0x0002,%bx      # long mode
+        int     $0x15
+#endif
+
         /*
          * Do real-mode work:
          *  1. Get memory map.