Re: grub-mkimage and module loading

[Hollis Blanchard <hollis@penguinppc.org>]

This is the updated version of the mkimage patch for PPC. It has been
tested on PowerPC, but only compile-tested on x86.

The interesting parts are in grub_load_modules(), where we no longer use
grub_end_addr and grub_get_end_addr() as the bounds of our modules.
Instead we call an arch-specific grub_arch_modules_addr(), and at that
location we find a struct grub_module_info, telling us the size of the
in-memory modules.

Note that now, grub_load_modules() is the only code that knows how large
the modules are. There were two other users of that information:
grub_add_unused_region() and i386/pc grub_machine_init(), and both are doing
the same thing: adding the module memory to the heap allocator.
grub_add_unused_region() was easily folded into grub_load_modules().
I believe the grub_machine_init use is unnecessary because the memory is
now given to the heap in grub_load_modules(). I have not confirmed this.

I know the common grub_load_modules() code works, but the corresponding i386
grub-mkimage additions need testing.

-Hollis

2004-01-02  Hollis Blanchard  <hollis@penguinppc.org>
	* TODO: Add note about endianness in grub-mkimage.
	* boot/powerpc/ieee1275/crt0.S (note): Remove unused .note
	section.
	* conf/powerpc-ieee1275.rmk (bin_UTILITIES): Add grub-mkimage.
	(grub_mkimage_SOURCES): New target.
	* include/grub/kernel.h (grub_start_addr): Remove variable.
	(grub_end_addr): Likewise.
	(grub_total_module_size): Likewise.
	(grub_kernel_image_size): Likewise.
	(GRUB_MODULE_MAGIC): New constant.
	(grub_module_info): New structure.
	(grub_arch_modules_addr): New prototype.
	(grub_get_end_addr): Remove prototype.
	* include/grub/i386/pc/kernel.h (grub_end_addr): New prototype.
	* include/grub/powerpc/ieee1275/kernel.h: New file.
	* include/grub/util/misc.h (grub_util_get_fp_size): New
	prototype.
	(grub_util_read_at): Likewise.
	(grub_util_write_image_at): Likewise.
	* kern/main.c (grub_get_end_addr): Remove function.
	(grub_load_modules): Call grub_arch_modules_addr instead of
	using grub_end_addr. Look for a grub_module_info struct in
	memory. Use the grub_module_info fields instead of calling
	grub_get_end_addr as loop conditions. Move
	grub_add_unused_region code here.
	(grub_add_unused_region): Remove function.
	* kern/i386/pc/init.c: Include grub/cache.h.
	(grub_machine_init): Remove call to grub_get_end_addr. Remove
	one call to add_mem_region.
	(grub_arch_modules_addr): New function.
	* kern/powerpc/ieee1275/init.c (grub_end_addr): Remove variable.
	(grub_total_module_size): Likewise.
	Include grub/machine/kernel.h.
	(grub_arch_modules_addr): New function.
	* util/grub-emu.c (grub_end_addr): Remove variable.
	(grub_total_module_size): Likewise.
	(grub_arch_modules_addr): New function.
	* util/misc.c: Include unistd.h.
	(grub_util_get_fp_size): New function.
	(grub_util_read_at): Likewise.
	(grub_util_write_image_at): Likewise.
	(grub_util_read_image): Call grub_util_read_at.
	(grub_util_write_image): Call grub_util_write_image_at.
	* util/i386/pc/grub-mkimage.c (generate_image): Allocate
	additional memory in kernel_img for a struct grub_module_info.
	Fill in that grub_module_info.
	* util/powerpc/ieee1275/grub-mkimage.c: New file.

Index: TODO
===================================================================
RCS file: /cvsroot/grub/grub2/TODO,v
retrieving revision 1.7
diff -u -p -r1.7 TODO
--- TODO	1 Aug 2004 13:19:38 -0000	1.7
+++ TODO	3 Jan 2005 02:56:55 -0000
@@ -39,3 +39,5 @@ Priorities:
 * Add a fancy menu interface which utilizes the graphics mode
   extensively with many eye-candies. This is important to beat
   GRUB legacy. :)
+
+* Audit util/powerpc/ieee1275/grub-mkimage.c for endianness fixes.
Index: boot/powerpc/ieee1275/crt0.S
===================================================================
RCS file: /cvsroot/grub/grub2/boot/powerpc/ieee1275/crt0.S,v
retrieving revision 1.4
diff -u -p -r1.4 crt0.S
--- boot/powerpc/ieee1275/crt0.S	28 Dec 2004 22:43:37 -0000	1.4
+++ boot/powerpc/ieee1275/crt0.S	3 Jan 2005 02:56:55 -0000
@@ -18,21 +18,6 @@
  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-	.section ".note"
-	.align	2
-.note_section_header:
-	.long	8
-	.long	24
-	.long	0x1275
-	.string	"PowerPC"
-.note_descriptor:
-	.long   0x0             /* real-mode */
-	.long   0xffffffff      /* real-base */
-	.long   0xffffffff      /* real-size */
-	.long   0xffffffff      /* virt-base */
-	.long   0xffffffff      /* virt-size */
-	.long   0x00030000      /* load-base */
-
 .extern __bss_start
 .extern _end
 
Index: conf/powerpc-ieee1275.rmk
===================================================================
RCS file: /cvsroot/grub/grub2/conf/powerpc-ieee1275.rmk,v
retrieving revision 1.18
diff -u -p -r1.18 powerpc-ieee1275.rmk
--- conf/powerpc-ieee1275.rmk	28 Dec 2004 22:43:37 -0000	1.18
+++ conf/powerpc-ieee1275.rmk	3 Jan 2005 02:56:57 -0000
@@ -24,9 +24,13 @@ kernel_syms.lst: $(addprefix include/gru
 pkgdata_PROGRAMS = grubof
 
 # Utilities.
-bin_UTILITIES = grub-emu
+bin_UTILITIES = grub-emu grub-mkimage
 noinst_UTILITIES = genmoddep
 
+# For grub-mkimage.
+grub_mkimage_SOURCES = util/powerpc/ieee1275/grub-mkimage.c util/misc.c \
+        util/resolve.c 
+
 # For grub-emu
 grub_emu_SOURCES = kern/main.c kern/device.c				\
 	kern/disk.c kern/dl.c kern/file.c kern/fs.c kern/err.c		\
Index: include/grub/kernel.h
===================================================================
RCS file: /cvsroot/grub/grub2/include/grub/kernel.h,v
retrieving revision 1.4
diff -u -p -r1.4 kernel.h
--- include/grub/kernel.h	4 Apr 2004 13:46:00 -0000	1.4
+++ include/grub/kernel.h	3 Jan 2005 02:56:57 -0000
@@ -31,17 +31,18 @@ struct grub_module_header
   grub_size_t size;
 };
 
-/* The start address of the kernel.  */
-extern grub_addr_t grub_start_addr;
+#define GRUB_MODULE_MAGIC 0x676d696d /* "gmim" (GRUB Module Info Magic).  */
 
-/* The end address of the kernel.  */
-extern grub_addr_t grub_end_addr;
+struct grub_module_info {
+  /* Magic number so we know we have modules present.  */
+  grub_uint32_t magic;
+  /* The offset of the modules.  */
+  grub_off_t offset;
+  /* The size of all modules plus this header.  */
+  grub_size_t size;
+};
 
-/* The total size of modules including their headers.  */
-extern grub_size_t grub_total_module_size;
-
-/* The size of the kernel image.  */
-extern grub_size_t grub_kernel_image_size;
+extern grub_addr_t grub_arch_modules_addr (void);
 
 /* The start point of the C code.  */
 void grub_main (void);
@@ -49,9 +50,6 @@ void grub_main (void);
 /* The machine-specific initialization. This must initialize memory.  */
 void grub_machine_init (void);
 
-/* Return the end address of the core image.  */
-grub_addr_t grub_get_end_addr (void);
-
 /* Register all the exported symbols. This is automatically generated.  */
 void grub_register_exported_symbols (void);
 
Index: include/grub/i386/pc/kernel.h
===================================================================
RCS file: /cvsroot/grub/grub2/include/grub/i386/pc/kernel.h,v
retrieving revision 1.5
diff -u -p -r1.5 kernel.h
--- include/grub/i386/pc/kernel.h	4 Apr 2004 13:46:01 -0000	1.5
+++ include/grub/i386/pc/kernel.h	3 Jan 2005 02:56:57 -0000
@@ -58,6 +58,9 @@ extern char grub_prefix[];
 /* The boot BIOS drive number.  */
 extern grub_int32_t grub_boot_drive;
 
+/* The end address of the kernel.  */
+extern grub_addr_t grub_end_addr;
+
 #endif /* ! ASM_FILE */
 
 #endif /* ! KERNEL_MACHINE_HEADER */
Index: include/grub/powerpc/ieee1275/kernel.h
===================================================================
RCS file: include/grub/powerpc/ieee1275/kernel.h
diff -N include/grub/powerpc/ieee1275/kernel.h
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ include/grub/powerpc/ieee1275/kernel.h	3 Jan 2005 02:56:57 -0000
@@ -0,0 +1,26 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2002  Free Software Foundation, Inc.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef GRUB_KERNEL_MACHINE_HEADER
+#define GRUB_KERNEL_MACHINE_HEADER	1
+
+/* Where grub-mkimage places the core modules in memory.  */
+#define MODULE_BASE 0x00300000
+
+#endif
Index: include/grub/util/misc.h
===================================================================
RCS file: /cvsroot/grub/grub2/include/grub/util/misc.h,v
retrieving revision 1.5
diff -u -p -r1.5 misc.h
--- include/grub/util/misc.h	4 Apr 2004 13:46:01 -0000	1.5
+++ include/grub/util/misc.h	3 Jan 2005 02:56:57 -0000
@@ -34,9 +34,13 @@ void *xrealloc (void *ptr, size_t size);
 char *xstrdup (const char *str);
 
 char *grub_util_get_path (const char *dir, const char *file);
+size_t grub_util_get_fp_size (FILE *fp);
 size_t grub_util_get_image_size (const char *path);
+void grub_util_read_at (void *img, size_t len, off_t offset, FILE *fp);
 char *grub_util_read_image (const char *path);
 void grub_util_load_image (const char *path, char *buf);
 void grub_util_write_image (const char *img, size_t size, FILE *out);
+void grub_util_write_image_at (const void *img, size_t size, off_t offset,
+			       FILE *out);
 
 #endif /* ! GRUB_UTIL_MISC_HEADER */
Index: kern/main.c
===================================================================
RCS file: /cvsroot/grub/grub2/kern/main.c,v
retrieving revision 1.8
diff -u -p -r1.8 main.c
--- kern/main.c	4 Apr 2004 13:46:01 -0000	1.8
+++ kern/main.c	3 Jan 2005 02:56:57 -0000
@@ -29,35 +29,31 @@
 #include <grub/device.h>
 #include <grub/env.h>
 
-/* Return the end of the core image.  */
-grub_addr_t
-grub_get_end_addr (void)
-{
-  return grub_total_module_size + grub_end_addr;
-}
-
 /* Load all modules in core.  */
 static void
 grub_load_modules (void)
 {
+  struct grub_module_info *modinfo;
   struct grub_module_header *header;
+  grub_addr_t modbase;
+
+  modbase = grub_arch_modules_addr ();
+  modinfo = (struct grub_module_info *) modbase;
+  if ((modinfo == 0) || modinfo->magic != GRUB_MODULE_MAGIC)
+    /* No modules.  */
+    return;
 
-  for (header = (struct grub_module_header *) grub_end_addr;
-       header < (struct grub_module_header *) grub_get_end_addr ();
+  for (header = (struct grub_module_header *) (modbase + modinfo->offset);
+       header < (struct grub_module_header *) (modbase + modinfo->size);
        header = (struct grub_module_header *) ((char *) header + header->size))
     {
       if (! grub_dl_load_core ((char *) header + header->offset,
 			       (header->size - header->offset)))
 	grub_fatal ("%s", grub_errmsg);
     }
-}
 
-/* Add the region where modules reside into dynamic memory.  */
-static void
-grub_add_unused_region (void)
-{
-  if (grub_total_module_size)
-    grub_mm_init_region ((void *) grub_end_addr, grub_total_module_size);
+  /* Add the region where modules reside into dynamic memory.  */
+  grub_mm_init_region ((void *) modinfo, modinfo->size);
 }
 
 /* Set the root device according to the dl prefix.  */
@@ -111,7 +107,6 @@ grub_main (void)
   /* Load pre-loaded modules and free the space.  */
   grub_register_exported_symbols ();
   grub_load_modules ();
-  grub_add_unused_region ();
 
   /* Load the normal mode module.  */
   grub_load_normal_mode ();
Index: kern/i386/pc/init.c
===================================================================
RCS file: /cvsroot/grub/grub2/kern/i386/pc/init.c,v
retrieving revision 1.9
diff -u -p -r1.9 init.c
--- kern/i386/pc/init.c	27 Dec 2004 13:46:20 -0000	1.9
+++ kern/i386/pc/init.c	3 Jan 2005 02:56:57 -0000
@@ -30,6 +30,7 @@
 #include <grub/misc.h>
 #include <grub/loader.h>
 #include <grub/env.h>
+#include <grub/cache.h>
 
 struct mem_region
 {
@@ -126,7 +127,6 @@ grub_machine_init (void)
   grub_uint32_t cont;
   struct grub_machine_mmap_entry *entry
     = (struct grub_machine_mmap_entry *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
-  grub_addr_t end_addr = grub_get_end_addr ();
   int i;
   
   /* Initialize the console as early as possible.  */
@@ -148,8 +148,6 @@ grub_machine_init (void)
     add_mem_region (GRUB_MEMORY_MACHINE_RESERVED_END,
 		    grub_lower_mem - GRUB_MEMORY_MACHINE_RESERVED_END);
   
-  add_mem_region (end_addr, GRUB_MEMORY_MACHINE_RESERVED_START - end_addr);
-
   /* Check if grub_get_mmap_entry works.  */
   cont = grub_get_mmap_entry (entry, 0);
 
@@ -233,3 +231,10 @@ grub_machine_init (void)
   /* Initialize the prefix.  */
   grub_env_set ("prefix", make_install_device ());
 }
+
+/* Return the end of the core image.  */
+grub_addr_t
+grub_arch_modules_addr (void)
+{
+  return grub_end_addr;
+}
Index: kern/powerpc/ieee1275/init.c
===================================================================
RCS file: /cvsroot/grub/grub2/kern/powerpc/ieee1275/init.c,v
retrieving revision 1.11
diff -u -p -r1.11 init.c
--- kern/powerpc/ieee1275/init.c	27 Dec 2004 13:46:20 -0000	1.11
+++ kern/powerpc/ieee1275/init.c	3 Jan 2005 02:56:57 -0000
@@ -31,10 +31,7 @@
 #include <grub/misc.h>
 #include <grub/machine/init.h>
 #include <grub/machine/time.h>
-
-/* XXX: Modules are not yet supported.  */
-grub_addr_t grub_end_addr = -1;
-grub_addr_t grub_total_module_size = 0;
+#include <grub/machine/kernel.h>
 
 void
 abort (void)
@@ -84,3 +81,9 @@ grub_get_rtc (void)
 {
   return 0;
 }
+
+grub_addr_t
+grub_arch_modules_addr (void)
+{
+  return MODULE_BASE;
+}
Index: util/grub-emu.c
===================================================================
RCS file: /cvsroot/grub/grub2/util/grub-emu.c,v
retrieving revision 1.9
diff -u -p -r1.9 grub-emu.c
--- util/grub-emu.c	4 Dec 2004 18:45:45 -0000	1.9
+++ util/grub-emu.c	3 Jan 2005 02:56:58 -0000
@@ -45,9 +45,11 @@
 
 #define DEFAULT_DEVICE_MAP	DEFAULT_DIRECTORY "/device.map"
 
-/* XXX.  */
-grub_addr_t grub_end_addr = -1;
-grub_addr_t grub_total_module_size = 0;
+grub_addr_t
+grub_arch_modules_addr (void)
+{
+  return 0;
+}
 
 int
 grub_arch_dl_check_header (void *ehdr, grub_size_t size)
Index: util/misc.c
===================================================================
RCS file: /cvsroot/grub/grub2/util/misc.c,v
retrieving revision 1.9
diff -u -p -r1.9 misc.c
--- util/misc.c	27 Dec 2004 13:46:20 -0000	1.9
+++ util/misc.c	3 Jan 2005 02:56:58 -0000
@@ -25,6 +25,7 @@
 #include <sys/stat.h>
 #include <sys/times.h>
 #include <malloc.h>
+#include <unistd.h>
 
 #include <grub/util/misc.h>
 #include <grub/mm.h>
@@ -107,6 +108,20 @@ grub_util_get_path (const char *dir, con
 }
 
 size_t
+grub_util_get_fp_size (FILE *fp)
+{
+  struct stat st;
+  
+  if (fflush (fp) == EOF)
+    grub_util_error ("fflush failed");
+
+  if (fstat (fileno (fp), &st) == -1)
+    grub_util_error ("fstat failed");
+  
+  return st.st_size;
+}
+
+size_t
 grub_util_get_image_size (const char *path)
 {
   struct stat st;
@@ -119,6 +134,16 @@ grub_util_get_image_size (const char *pa
   return st.st_size;
 }
 
+void
+grub_util_read_at (void *img, size_t size, off_t offset, FILE *fp)
+{
+  if (fseek (fp, offset, SEEK_SET) == -1)
+    grub_util_error ("fseek failed");
+
+  if (fread (img, 1, size, fp) != size)
+    grub_util_error ("read failed");
+}
+
 char *
 grub_util_read_image (const char *path)
 {
@@ -134,9 +159,8 @@ grub_util_read_image (const char *path)
   fp = fopen (path, "rb");
   if (! fp)
     grub_util_error ("cannot open %s", path);
-  
-  if (fread (img, 1, size, fp) != size)
-    grub_util_error ("cannot read %s", path);
+
+  grub_util_read_at (img, size, 0, fp);
 
   fclose (fp);
   
@@ -164,13 +188,21 @@ grub_util_load_image (const char *path, 
 }
 
 void
-grub_util_write_image (const char *img, size_t size, FILE *out)
+grub_util_write_image_at (const void *img, size_t size, off_t offset, FILE *out)
 {
-  grub_util_info ("writing 0x%x bytes", size);
+  grub_util_info ("writing 0x%x bytes at offset 0x%x", size, offset);
+  if (fseek (out, offset, SEEK_SET) == -1)
+    grub_util_error ("seek failed");
   if (fwrite (img, 1, size, out) != size)
     grub_util_error ("write failed");
 }
 
+void
+grub_util_write_image (const char *img, size_t size, FILE *out)
+{
+  grub_util_write_image_at (img, size, 0, out);
+}
+
 void *
 grub_malloc (unsigned size)
 {
Index: util/i386/pc/grub-mkimage.c
===================================================================
RCS file: /cvsroot/grub/grub2/util/i386/pc/grub-mkimage.c,v
retrieving revision 1.6
diff -u -p -r1.6 grub-mkimage.c
--- util/i386/pc/grub-mkimage.c	4 Apr 2004 13:46:03 -0000	1.6
+++ util/i386/pc/grub-mkimage.c	3 Jan 2005 02:56:58 -0000
@@ -79,13 +79,14 @@ generate_image (const char *dir, FILE *o
   unsigned num;
   size_t offset;
   struct grub_util_path_list *path_list, *p, *next;
+  struct grub_module_info *modinfo;
 
   path_list = grub_util_resolve_dependencies (dir, "moddep.lst", mods);
 
   kernel_path = grub_util_get_path (dir, "kernel.img");
   kernel_size = grub_util_get_image_size (kernel_path);
 
-  total_module_size = 0;
+  total_module_size = sizeof (struct grub_module_info);
   for (p = path_list; p; p = p->next)
     total_module_size += (grub_util_get_image_size (p->name)
 			  + sizeof (struct grub_module_header));
@@ -94,7 +95,14 @@ generate_image (const char *dir, FILE *o
 
   kernel_img = xmalloc (kernel_size + total_module_size);
   grub_util_load_image (kernel_path, kernel_img);
-  offset = kernel_size;
+
+  /* Fill in the grub_module_info structure.  */
+  modinfo = (struct grub_module_info *) (kernel_img + kernel_size);
+  modinfo->magic = GRUB_MODULE_MAGIC;
+  modinfo->offset = sizeof (struct grub_module_info);
+  modinfo->size = total_module_size;
+
+  offset = kernel_size + sizeof (struct grub_module_info);
   for (p = path_list; p; p = p->next)
     {
       struct grub_module_header *header;
Index: util/powerpc/ieee1275/grub-mkimage.c
===================================================================
RCS file: util/powerpc/ieee1275/grub-mkimage.c
diff -N util/powerpc/ieee1275/grub-mkimage.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ util/powerpc/ieee1275/grub-mkimage.c	3 Jan 2005 02:56:58 -0000
@@ -0,0 +1,298 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2004  Free Software Foundation, Inc.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <stdlib.h>
+#include <grub/elf.h>
+#include <grub/util/misc.h>
+#include <grub/util/resolve.h>
+#include <grub/kernel.h>
+#include <grub/machine/kernel.h>
+
+#define ALIGN_UP(addr, align) ((long)((char *)addr + align - 1) & ~(align - 1))
+
+static char *kernel_path = "grubof";
+static char *note_path = "note";
+
+
+void
+load_note (Elf32_Phdr *phdr, const char *dir, FILE *out)
+{
+  char *note_img;
+  char *path;
+  int note_size;
+
+  grub_util_info ("adding CHRP NOTE segment");
+
+  path = grub_util_get_path (dir, note_path);
+  note_size = grub_util_get_image_size (path);
+  note_img = xmalloc (note_size);
+  grub_util_load_image (path, note_img);
+  free (path);
+
+  /* Write the note data to the new segment.  */
+  grub_util_write_image_at (note_img, note_size, phdr->p_offset, out);
+
+  /* Fill in the rest of the segment header.  */
+  phdr->p_type = PT_NOTE;
+  phdr->p_flags = PF_R;
+  phdr->p_align = sizeof (long);
+  phdr->p_vaddr = 0;
+  phdr->p_paddr = 0;
+  phdr->p_filesz = note_size;
+  phdr->p_memsz = 0;
+}
+
+void
+load_modules (Elf32_Phdr *phdr, const char *dir, char *mods[], FILE *out)
+{
+  char *module_img;
+  struct grub_util_path_list *path_list;
+  struct grub_util_path_list *p;
+  struct grub_module_info *modinfo;
+  size_t offset;
+  size_t total_module_size;
+
+  path_list = grub_util_resolve_dependencies (dir, "moddep.lst", mods);
+
+  offset = sizeof (struct grub_module_info);
+  total_module_size = sizeof (struct grub_module_info);
+  for (p = path_list; p; p = p->next)
+    {
+      total_module_size += (grub_util_get_image_size (p->name)
+	  + sizeof (struct grub_module_header));
+    }
+
+  grub_util_info ("the total module size is 0x%x", total_module_size);
+
+  module_img = xmalloc (total_module_size);
+  modinfo = (struct grub_module_info *) module_img;
+  modinfo->magic = GRUB_MODULE_MAGIC;
+  modinfo->offset = sizeof (struct grub_module_info);
+  modinfo->size = total_module_size;
+
+  /* Load all the modules, with headers, into module_img.  */
+  for (p = path_list; p; p = p->next)
+    {
+      struct grub_module_header *header;
+      size_t mod_size;
+
+      grub_util_info ("adding module %s", p->name);
+
+      mod_size = grub_util_get_image_size (p->name);
+
+      header = (struct grub_module_header *) (module_img + offset);
+      header->offset = grub_cpu_to_be32 (sizeof (*header));
+      header->size = grub_cpu_to_be32 (mod_size + sizeof (*header));
+
+      grub_util_load_image (p->name, module_img + offset + sizeof (*header));
+
+      offset += sizeof (*header) + mod_size;
+    }
+
+  /* Write the module data to the new segment.  */
+  grub_util_write_image_at (module_img, total_module_size, phdr->p_offset, out);
+
+  /* Fill in the rest of the segment header.  */
+  phdr->p_type = PT_LOAD;
+  phdr->p_flags = PF_R | PF_W | PF_X;
+  phdr->p_align = sizeof (long);
+  phdr->p_vaddr = MODULE_BASE;
+  phdr->p_paddr = MODULE_BASE;
+  phdr->p_filesz = total_module_size;
+  phdr->p_memsz = total_module_size;
+}
+
+void
+add_segments (char *dir, FILE *out, int chrp, char *mods[])
+{
+  Elf32_Ehdr ehdr;
+  Elf32_Phdr *phdrs = NULL;
+  Elf32_Phdr *phdr;
+  FILE *in;
+  off_t phdroff;
+  int i;
+
+  /* Read ELF header.  */
+  in = fopen (kernel_path, "rb");
+  if (! in)
+    grub_util_error ("cannot open %s", kernel_path);
+  grub_util_read_at (&ehdr, sizeof (ehdr), 0, in);
+
+  phdrs = xmalloc (ehdr.e_phentsize * (ehdr.e_phnum + 2));
+
+  /* Copy all existing segments.  */
+  for (i = 0; i < ehdr.e_phnum; i++)
+    {
+      char *segment_img;
+
+      phdr = phdrs + i;
+
+      /* Read segment header.  */
+      grub_util_read_at (phdr, sizeof (Elf32_Phdr), ehdr.e_phoff
+			 + (i * ehdr.e_phentsize), in);
+      grub_util_info ("copying segment %d, type %d", i, phdr->p_type);
+
+      /* Read segment data and write it to new file.  */
+      segment_img = xmalloc (phdr->p_filesz);
+      grub_util_read_at (segment_img, phdr->p_filesz, phdr->p_offset, in);
+      grub_util_write_image_at (segment_img, phdr->p_filesz, phdr->p_offset, out);
+
+      free (segment_img);
+    }
+
+  if (mods[0] != NULL)
+    {
+      /* Construct new segment header for modules.  */
+      phdr = phdrs + ehdr.e_phnum;
+      ehdr.e_phnum++;
+
+      /* Fill in p_offset so the callees know where to write.  */
+      phdr->p_offset = ALIGN_UP (grub_util_get_fp_size (out), sizeof (long));
+
+      load_modules (phdr, dir, mods, out);
+    }
+
+  if (chrp)
+    {
+      /* Construct new segment header for the CHRP note.  */
+      phdr = phdrs + ehdr.e_phnum;
+      ehdr.e_phnum++;
+
+      /* Fill in p_offset so the callees know where to write.  */
+      phdr->p_offset = ALIGN_UP (grub_util_get_fp_size (out), sizeof (long));
+
+      load_note (phdr, dir, out);
+    }
+
+  /* Don't bother preserving the section headers.  */
+  ehdr.e_shoff = 0;
+  ehdr.e_shnum = 0;
+  ehdr.e_shstrndx = 0;
+
+  /* Append entire segment table to the file.  */
+  phdroff = ALIGN_UP (grub_util_get_fp_size (out), sizeof (long));
+  grub_util_write_image_at (phdrs, ehdr.e_phentsize * ehdr.e_phnum, phdroff,
+			    out);
+
+  /* Write ELF header.  */
+  ehdr.e_phoff = phdroff;
+  grub_util_write_image_at (&ehdr, sizeof (ehdr), 0, out);
+
+  free (phdrs);
+}
+
+static struct option options[] =
+  {
+    {"directory", required_argument, 0, 'd'},
+    {"output", required_argument, 0, 'o'},
+    {"help", no_argument, 0, 'h'},
+    {"note", no_argument, 0, 'n'},
+    {"version", no_argument, 0, 'V'},
+    {"verbose", no_argument, 0, 'v'},
+    { 0, 0, 0, 0 },
+  };
+
+static void
+usage (int status)
+{
+  if (status)
+    fprintf (stderr, "Try ``grub-mkimage --help'' for more information.\n");
+  else
+    printf ("\
+Usage: grub-mkimage -o FILE [OPTION]... [MODULES]\n\
+\n\
+Make a bootable image of GRUB.\n\
+\n\
+-d, --directory=DIR     use images and modules under DIR [default=%s]\n\
+-o, --output=FILE       output a generated image to FILE\n\
+-h, --help              display this message and exit\n\
+-n, --note              add NOTE segment for CHRP Open Firmware\n\
+-V, --version           print version information and exit\n\
+-v, --verbose           print verbose messages\n\
+\n\
+Report bugs to <%s>.\n\
+", GRUB_DATADIR, PACKAGE_BUGREPORT);
+
+  exit (status);
+}
+
+int
+main (int argc, char *argv[])
+{
+  FILE *fp;
+  char *output = NULL;
+  char *dir = NULL;
+  int chrp = 0;
+
+  progname = "grub-mkimage";
+
+  while (1)
+    {
+      int c = getopt_long (argc, argv, "d:o:hVvn", options, 0);
+      if (c == -1)
+	break;
+
+      switch (c)
+	{
+	  case 'd':
+	    if (dir)
+	      free (dir);
+	    dir = xstrdup (optarg);
+	    break;
+	  case 'h':
+	    usage (0);
+	    break;
+	  case 'n':
+	    chrp = 1;
+	    break;
+	  case 'o':
+	    if (output)
+	      free (output);
+	    output = xstrdup (optarg);
+	    break;
+	  case 'V':
+	    printf ("grub-mkimage (%s) %s\n", PACKAGE_NAME, PACKAGE_VERSION);
+	    return 0;
+	  case 'v':
+	    verbosity++;
+	    break;
+	  default:
+	    usage (1);
+	    break;
+	}
+  }
+
+  if (!output)
+    usage (1);
+
+  fp = fopen (output, "wb");
+  if (! fp)
+    grub_util_error ("cannot open %s", output);
+
+  add_segments (dir ? : GRUB_DATADIR, fp, chrp, argv + optind);
+
+  fclose (fp);
+
+  return 0;
+}