2008-07-30 Robert Millan <rmh@aybabtu.com>

* kern/ieee1275/init.c (grub_machine_set_prefix): If `grub_prefix'
        is non-empty, use it to set the `prefix' environment variable instead
        of the usual approach.
        * kern/i386/linuxbios/init.c (make_install_device): Remove function.
        (grub_machine_set_prefix): Use `grub_prefix' to set the `prefix'
        environment variable instead of dummy make_install_device().

        * kern/i386/ieee1275/startup.S: Include `<grub/machine/kernel.h>'.
        (start): Insert a data section, with `grub_prefix' variable.
        * kern/i386/linuxbios/startup.S: Likewise.

        * include/grub/powerpc/ieee1275/kernel.h [!ASM_FILE] (grub_prefix):
        New variable reference.
        * include/grub/i386/ieee1275/kernel.h (GRUB_KERNEL_MACHINE_PREFIX):
        New macro.  Defines offset of `grub_prefix' within startup.S (relative
        to `start').
        (GRUB_KERNEL_MACHINE_DATA_END): New macro.  Defines the end of data
        section within startup.S (relative to `start').
        * include/grub/i386/coreboot/kernel.h: Likewise.

        * util/elf/grub-mkimage.c (add_segments): Receive `prefix' parameter.
        Overwrite grub_prefix with its contents, at the beginning of the
        first segment.
        (main): Understand -p|--prefix.

kern/i386/ieee1275/startup.S

@@ -19,6 +19,7 @@
 #define ASM_FILE	1
 
 #include <grub/symbol.h>
+#include <grub/machine/kernel.h>
 #include <grub/machine/memory.h>
 #include <grub/cpu/linux.h>
 #include <multiboot.h>
@@ -38,6 +39,24 @@
 
 start:
 _start:
+	jmp codestart
+
+	/*
+	 *  This is a special data area at a fixed offset from the beginning.
+	 */
+
+	. = EXT_C(start) + GRUB_KERNEL_MACHINE_PREFIX
+
+VARIABLE(grub_prefix)
+	/* to be filled by grub-mkimage */
+
+	/*
+	 *  Leave some breathing room for the prefix.
+	 */
+
+	. = EXT_C(start) + GRUB_KERNEL_MACHINE_DATA_END
+
+codestart:
 	movl %eax, EXT_C(grub_ieee1275_entry_fn)
 	jmp EXT_C(grub_main)
 

kern/i386/linuxbios/init.c

@@ -78,12 +78,6 @@ grub_arch_sync_caches (void *address __attribute__ ((unused)),
 {
 }
 
-static char *
-make_install_device (void)
-{
-  return NULL;
-}
-
 void
 grub_machine_init (void)
 {
@@ -155,7 +149,7 @@ void
 grub_machine_set_prefix (void)
 {
   /* Initialize the prefix.  */
-  grub_env_set ("prefix", make_install_device ());
+  grub_env_set ("prefix", grub_prefix);
 }
 
 void

kern/i386/linuxbios/startup.S

@@ -19,6 +19,7 @@
 #define ASM_FILE	1
 
 #include <grub/symbol.h>
+#include <grub/machine/kernel.h>
 #include <grub/machine/memory.h>
 #include <grub/cpu/linux.h>
 #include <multiboot.h>
@@ -35,6 +36,24 @@
 	.file	"startup.S"
 	.text
 	.globl	start, _start
+start:
+_start:
+	jmp codestart
+
+	/*
+	 *  This is a special data area at a fixed offset from the beginning.
+	 */
+
+	. = EXT_C(start) + GRUB_KERNEL_MACHINE_PREFIX
+
+VARIABLE(grub_prefix)
+	/* to be filled by grub-mkimage */
+
+	/*
+	 *  Leave some breathing room for the prefix.
+	 */
+
+	. = EXT_C(start) + GRUB_KERNEL_MACHINE_DATA_END
 
 #if 0
 /*
@@ -49,8 +68,7 @@ multiboot_header:
 	.long	-0x1BADB002
 #endif
 
-start:
-_start:
+codestart:
 	/* initialize the stack */
 	movl $GRUB_MEMORY_MACHINE_PROT_STACK, %esp
 

kern/ieee1275/init.c

@@ -84,6 +84,13 @@ grub_machine_set_prefix (void)
     /* We already set prefix in grub_machine_init().  */
     return;
 
+  if (grub_prefix[0])
+    {
+      grub_env_set ("prefix", grub_prefix);
+      /* Prefix is hardcoded in the core image.  */
+      return;
+    }
+
   if (grub_ieee1275_get_property (grub_ieee1275_chosen, "bootpath", &bootpath,
 				  sizeof (bootpath), 0))
     {