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List Archive: gentoo-releng
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To: gentoo-releng@g.o
From: Joshua Hoblitt <jhoblitt@...>
Subject: Fwd: grub 0.97 does not support GPT partitions
Date: Mon, 14 May 2007 14:18:13 -1000
Grub 0.97 does not including support for GPT partition tables and
upstream has stated that they have no intention of adding this support
is it is a Grub "2" feature.  Perhaps this is a pessimistic view point but
I don't believe we'll be seeing a stable Grub "2" release for some time.

This going to become a serious problem for many users in the near future
as storage devices in excess of 2TB are becoming more and more common.
We're likely just few years away from seeing single disks in this size
range.

In my case, I've encountered this issue already with 10TB RAID sets that
I'd like to be able to boot from.  I've been able to work around this
limitation in two ways.  1) cutting the RAID set up into multiple
volumes with first one being smaller than 2TB so it can host a msdos
partition table or 2) building my own liveCD with a patched version of
grub that supports GPT partition tables and using a portage overlay with
the same patched version of grub.  It is my belief that fix #2 is the
more elegant solution.  Therefore I'd like to propose that Gentoo
patches grub to support GPT partitions.  The patch that I pulled from
the grub mailing lists to add this support is attached and I can attest
that it is functional in a production environment.

Thoughts?

-J

--
diff -ruBbd --unidirectional-new-file grub-0.96/stage2/builtins.c grub-0.96-patched/stage2/builtins.c
--- grub-0.96/stage2/builtins.c	2004-06-20 09:33:04.000000000 -0400
+++ grub-0.96-patched/stage2/builtins.c	2007-01-04 13:56:06.000000000 -0500
@@ -1229,14 +1229,15 @@
   for (drive = 0x80; drive < 0x88; drive++)
     {
       unsigned long part = 0xFFFFFF;
-      unsigned long start, len, offset, ext_offset;
-      int type, entry;
+      unsigned long start, len, offset, ext_offset, gpt_offset;
+      int type, entry, gpt_count, gpt_size;
       char buf[SECTOR_SIZE];
 
       current_drive = drive;
       while (next_partition (drive, 0xFFFFFF, &part, &type,
 			     &start, &len, &offset, &entry,
-			     &ext_offset, buf))
+                            &ext_offset, &gpt_offset,
+                            &gpt_count, &gpt_size, buf))
 	{
 	  if (type != PC_SLICE_TYPE_NONE
 	      && ! IS_PC_SLICE_TYPE_BSD (type)
@@ -2806,8 +2807,8 @@
 {
   int new_type;
   unsigned long part = 0xFFFFFF;
-  unsigned long start, len, offset, ext_offset;
-  int entry, type;
+  unsigned long start, len, offset, ext_offset, gpt_offset;
+  int entry, type, gpt_count, gpt_size;
   char mbr[512];
 
   /* Get the drive and the partition.  */
@@ -2844,7 +2845,14 @@
   /* Look for the partition.  */
   while (next_partition (current_drive, 0xFFFFFF, &part, &type,
 			 &start, &len, &offset, &entry,
-			 &ext_offset, mbr))
+			 &ext_offset, &gpt_offset, &gpt_count, &gpt_size, mbr))
+	  /* The partition may not be a GPT partition.  */
+	  if (gpt_offset != 0)
+	    {
+		errnum = ERR_BAD_ARGUMENT;
+		return 1;
+	    }
+
     {
       if (part == current_partition)
 	{
diff -ruBbd --unidirectional-new-file grub-0.96/stage2/disk_io.c grub-0.96-patched/stage2/disk_io.c
--- grub-0.96/stage2/disk_io.c	2004-05-23 12:35:24.000000000 -0400
+++ grub-0.96-patched/stage2/disk_io.c	2007-01-04 14:01:08.000000000 -0500
@@ -21,6 +21,7 @@
 
 #include <shared.h>
 #include <filesys.h>
+#include <gpt.h>
 
 #ifdef SUPPORT_NETBOOT
 # define GRUB	1
@@ -502,8 +503,8 @@
 set_partition_hidden_flag (int hidden)
 {
   unsigned long part = 0xFFFFFF;
-  unsigned long start, len, offset, ext_offset;
-  int entry, type;
+  unsigned long start, len, offset, ext_offset, gpt_offset;
+  int entry, type, gpt_count, gpt_size;
   char mbr[512];
   
   /* The drive must be a hard disk.  */
@@ -524,7 +525,14 @@
   /* Look for the partition.  */
   while (next_partition (current_drive, 0xFFFFFF, &part, &type,           
 			 &start, &len, &offset, &entry,
-			 &ext_offset, mbr))
+			 &ext_offset, &gpt_offset, &gpt_count, &gpt_size, mbr))
+	  /* The partition may not be a GPT partition.  */
+	  if (gpt_offset != 0)
+	    {
+		errnum = ERR_BAD_ARGUMENT;
+		return 1;
+	    }
+
     {                                                                       
       if (part == current_partition)
 	{
@@ -577,11 +585,14 @@
 		unsigned long *partition, int *type,
 		unsigned long *start, unsigned long *len,
 		unsigned long *offset, int *entry,
-		unsigned long *ext_offset, char *buf)
+               unsigned long *ext_offset,
+               unsigned long *gpt_offset, int *gpt_count,
+               int *gpt_size, char *buf)
 {
   /* Forward declarations.  */
   auto int next_bsd_partition (void);
   auto int next_pc_slice (void);
+  auto int next_gpt_slice(void);
 
   /* Get next BSD partition in current PC slice.  */
   int next_bsd_partition (void)
@@ -666,6 +677,40 @@
 	  return 0;
 	}
 
+      /* If this is a GPT partition table, read it as such.  */
+      if (*entry == -1 && *offset == 0 && PC_SLICE_TYPE (buf, 0) == PC_SLICE_TYPE_GPT)
+       {
+         struct grub_gpt_header *hdr = (struct grub_gpt_header *) buf;
+
+         /* Read in the GPT Partition table header.  */
+         if (! rawread (drive, 1, 0, SECTOR_SIZE, buf))
+           return 0;
+
+         if (hdr->magic == GPT_HEADER_MAGIC && hdr->version == 0x10000)
+           {
+             /* Let gpt_offset point to the first entry in the GPT
+                partition table.  This can also be used by callers of
+                next_partition to determine if a entry comes from a
+                GPT partition table or not.  */
+             *gpt_offset = hdr->partitions;
+             *gpt_count = hdr->maxpart;
+             *gpt_size =  hdr->partentry_size;
+             
+             return next_gpt_slice();
+           }
+         else
+           {
+             /* This is not a valid header for a GPT partition table.
+                Re-read the MBR or the boot sector of the extended
+                partition.  */
+             if (! rawread (drive, *offset, 0, SECTOR_SIZE, buf))
+               return 0;
+           }
+       }
+
+      /* Not a GPT partition.  */
+      *gpt_offset = 0;
+
       /* Increase the entry number.  */
       (*entry)++;
 
@@ -710,6 +755,43 @@
       return 1;
     }
 
+  /* Get the next GPT slice.  */
+  int next_gpt_slice (void)
+    {
+      struct grub_gpt_partentry *gptentry = (struct grub_gpt_partentry *) buf;
+      /* Make GPT partitions show up as PC slices.  */
+      int pc_slice_no = (*partition & 0xFF0000) >> 16;
+
+      /* If this is the first time...  */
+      if (pc_slice_no == 0xFF)
+       {
+         pc_slice_no = -1;
+         *entry = -1;
+       }
+
+      do {
+       (*entry)++;
+
+       if (*entry >= *gpt_count)
+         {
+           errnum = ERR_NO_PART;
+           return 0;
+         }
+       /* Read in the GPT Partition table entry.  */
+       if (! rawread (drive, (*gpt_offset) + GPT_ENTRY_SECTOR (*gpt_size, *entry), GPT_ENTRY_INDEX (*gpt_size, *entry), *gpt_size, buf))
+         return 0;
+      } while (! (gptentry->type1 && gptentry->type2));
+
+      pc_slice_no++;
+      *start = gptentry->start;
+      *len = gptentry->end - gptentry->start + 1;
+      *type = PC_SLICE_TYPE_EXT2FS;
+      *entry = pc_slice_no;
+      *partition = (*entry << 16) | 0xFFFF;
+
+      return 1;
+    }
+
   /* Start the body of this function.  */
   
 #ifndef STAGE1_5
@@ -717,6 +799,9 @@
     return 0;
 #endif
 
+  if (*partition != 0xFFFFFF && *gpt_offset != 0)
+    return next_gpt_slice ();
+
   /* If previous partition is a BSD partition or a PC slice which
      contains BSD partitions...  */
   if ((*partition != 0xFFFFFF && IS_PC_SLICE_TYPE_BSD (*type & 0xff))
@@ -755,6 +840,9 @@
   unsigned long dest_partition = current_partition;
   unsigned long part_offset;
   unsigned long ext_offset;
+  unsigned long gpt_offset;
+  int gpt_count;
+  int gpt_size;
   int entry;
   char buf[SECTOR_SIZE];
   int bsd_part, pc_slice;
@@ -766,7 +854,8 @@
       int ret = next_partition (current_drive, dest_partition,
 				&current_partition, &current_slice,
 				&part_start, &part_length,
-				&part_offset, &entry, &ext_offset, buf);
+                               &part_offset, &entry, &ext_offset,
+                               &gpt_offset, &gpt_count, &gpt_size, buf);
       bsd_part = (current_partition >> 8) & 0xFF;
       pc_slice = current_partition >> 16;
       return ret;
diff -ruBbd --unidirectional-new-file grub-0.96/stage2/gpt.h grub-0.96-patched/stage2/gpt.h
--- grub-0.96/stage2/gpt.h	1969-12-31 19:00:00.000000000 -0500
+++ grub-0.96-patched/stage2/gpt.h	2007-01-04 13:52:14.000000000 -0500
@@ -0,0 +1,68 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2002,2005,2006   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 _GPT_H
+#define _GPT_H
+
+typedef signed char grub_int8_t;
+typedef signed short grub_int16_t;
+typedef signed int grub_int32_t;
+typedef signed long long int grub_int64_t;
+typedef unsigned char grub_uint8_t;
+typedef unsigned short grub_uint16_t;
+typedef unsigned int grub_uint32_t;
+typedef unsigned long long int grub_uint64_t;
+
+struct grub_gpt_header
+{
+  grub_uint64_t magic;
+  grub_uint32_t version;
+  grub_uint32_t headersize;
+  grub_uint32_t crc32;
+  grub_uint32_t unused1;
+  grub_uint64_t primary;
+  grub_uint64_t backup;
+  grub_uint64_t start;
+  grub_uint64_t end;
+  grub_uint8_t guid[16];
+  grub_uint64_t partitions;
+  grub_uint32_t maxpart;
+  grub_uint32_t partentry_size;
+  grub_uint32_t partentry_crc32;
+} __attribute__ ((packed));
+
+struct grub_gpt_partentry
+{
+  grub_uint64_t type1;
+  grub_uint64_t type2;
+  grub_uint8_t guid[16];
+  grub_uint64_t start;
+  grub_uint64_t end;
+  grub_uint8_t attrib;
+  char name[72];
+} __attribute__ ((packed));
+
+#define GPT_HEADER_MAGIC       0x5452415020494645UL
+
+#define        GPT_ENTRY_SECTOR(size,entry)                                    \
+       ((((entry) * (size) + 1) & ~(SECTOR_SIZE - 1)) >> SECTOR_BITS)
+#define        GPT_ENTRY_INDEX(size,entry)                                     \
+       ((((entry) * (size) + 1) & (SECTOR_SIZE - 1)) - 1)
+
+#endif /* _GPT_H */
diff -ruBbd --unidirectional-new-file grub-0.96/stage2/pc_slice.h grub-0.96-patched/stage2/pc_slice.h
--- grub-0.96/stage2/pc_slice.h	2003-07-09 07:45:53.000000000 -0400
+++ grub-0.96-patched/stage2/pc_slice.h	2007-01-04 13:52:14.000000000 -0500
@@ -115,6 +115,7 @@
 #define PC_SLICE_TYPE_LINUX_EXTENDED	0x85
 #define PC_SLICE_TYPE_VSTAFS		0x9e
 #define PC_SLICE_TYPE_DELL_UTIL		0xde
+#define PC_SLICE_TYPE_GPT              0xee
 #define PC_SLICE_TYPE_LINUX_RAID	0xfd
 
 
diff -ruBbd --unidirectional-new-file grub-0.96/stage2/shared.h grub-0.96-patched/stage2/shared.h
--- grub-0.96/stage2/shared.h	2004-06-19 12:40:09.000000000 -0400
+++ grub-0.96-patched/stage2/shared.h	2007-01-04 13:52:15.000000000 -0500
@@ -934,7 +934,9 @@
 		    unsigned long *partition, int *type,
 		    unsigned long *start, unsigned long *len,
 		    unsigned long *offset, int *entry,
-		    unsigned long *ext_offset, char *buf);
+                   unsigned long *ext_offset,
+                   unsigned long *gpt_offset, int *gpt_count,
+                   int *gpt_size, char *buf);
 
 /* Sets device to the one represented by the SAVED_* parameters. */
 int make_saved_active (void);
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Re: Fwd: grub 0.97 does not support GPT partitions
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