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>

2 files changed, 11 insertions, 1 deletions

diff --git a/arch/x86/boot/compressed/cmdline.c b/arch/x86/boot/compressed/cmdline.c
index b4c913c5c4ad..bffd73b45b1f 100644
--- a/arch/x86/boot/compressed/cmdline.c
+++ b/arch/x86/boot/compressed/cmdline.c
@@ -17,6 +17,8 @@ static unsigned long get_cmd_line_ptr(void)
 {
         unsigned long cmd_line_ptr = real_mode->hdr.cmd_line_ptr;
 
+        cmd_line_ptr |= (u64)real_mode->ext_cmd_line_ptr << 32;
+
         return cmd_line_ptr;
 }
 int cmdline_find_option(const char *option, char *buffer, int bufsize)
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 944ce595f767..9ec06a1f6d61 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -374,6 +374,14 @@ xloadflags:
 #else
 # define XLF0 0
 #endif
+
+#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_X86_64)
+   /* kernel/boot_param/ramdisk could be loaded above 4g */
+# define XLF1 XLF_CAN_BE_LOADED_ABOVE_4G
+#else
+# define XLF1 0
+#endif
+
 #ifdef CONFIG_EFI_STUB
 # ifdef CONFIG_X86_64
 #  define XLF23 XLF_EFI_HANDOVER_64             /* 64-bit EFI handover ok */
@@ -383,7 +391,7 @@ xloadflags:
 #else
 # define XLF23 0
 #endif
-                        .word XLF0 | XLF23
+                        .word XLF0 | XLF1 | XLF23
 
 cmdline_size:   .long   COMMAND_LINE_SIZE-1     #length of the command line,
                                                 #added with boot protocol