x86: Allow selection of graphical video modes during boot.

The 'vga=' boot option is extended as follows:

----------
 'vga=<mode-specifier>[,keep]' where <mode-specifier> is one of:

   'vga=ask':
      display a vga menu of available modes

   'vga=text-80x<rows>':
      text mode, where <rows> is one of {25,28,30,34,43,50,60}

   'vga=gfx-<width>x<height>x<depth>':
      graphics mode, e.g., vga=gfx-1024x768x16

   'vga=mode-<mode>:
      specifies a mode as specified in 'vga=ask' menu
      (NB. menu modes are displayed in hex, so mode numbers here must
           be prefixed with '0x' (e.g., 'vga=mode-0x0318'))

 The option 'keep' causes Xen to continue to print to the VGA console even
 after domain 0 starts to boot. The default behaviour is to relinquish
 control of the console to domain 0.
----------

Signed-off-by: Keir Fraser <keir@xensource.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 48e54bb071..4a987bbd56 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -73,6 +73,7 @@ __start:
         mov     $BOOT_DS,%ecx
         mov     %ecx,%ds
         mov     %ecx,%es
+        mov     %ecx,%ss
 
         /* Check for Multiboot bootloader */
         cmp     $0x2BADB002,%eax
@@ -166,9 +167,14 @@ __start:
         mov     $trampoline_end - trampoline_start,%ecx
         rep     movsb
 
+        mov     $0x98000,%esp
+        call    cmdline_parse_early
+
         /* Jump into the relocated trampoline. */
         jmp     $BOOT_CS32,$bootsym_phys(trampoline_boot_cpu_entry)
 
+#include "cmdline.S"
+
         .globl trampoline_start, trampoline_end
 trampoline_start:
 #include "trampoline.S"