pass the boot partition information to a chain-loader, in the partition table area of the loader.

ChangeLog

@@ -1,3 +1,29 @@
+2000-02-16  OKUJI Yoshinori  <okuji@gnu.org>
+
+	Pass the boot partition information to a chain-loader, in the
+	partition table area of the loader, instead of right before the
+	loaded address. Reported by takehiro@coral.ocn.ne.jp (Takehiro
+	Suzuki).
+	
+	* stage2/builtins.c (chainloader_func): Embed the partition
+	table of the boot drive in the partition table area of the
+	chain-loader, if the boot drive is a hard disk drive.
+	Pass BOOT_PART_ADDR instead of (BOOTSEC_LOCATION - 16) as the
+	third argument for the function chain_stage1.
+	* stage2/disk_io.c [!STAGE1_5] (boot_part_addr): New variable.
+	[!STAGE1_5] (boot_part_offset): Likewise.
+	[!STAGE1_5] (cur_part_offset): Likewise.
+	[!STAGE1_5] (cur_part_addr): Likewise.
+	[!STAGE1_5] (cur_part_desc): Removed.
+	(real_open_partition) [!STAGE1_5]: Set CUR_PART_OFFSET and
+	CUR_PART_ADDR to PART_OFFSET and (BOOTSEC_LOCATION +
+	PC_SLICE_OFFSET + (i << 4)), respectively.
+	[!STAGE1_5] (set_bootdev): Set BOOT_PART_OFFSET and
+	BOOT_PART_ADDR to CUR_PART_OFFSET and CUR_PART_ADDR,
+	respectively.
+	* stage2/shared.h (boot_part_addr): Declared.
+	(boot_part_offset): Likewise.
+	
 2000-02-12  OKUJI Yoshinori  <okuji@gnu.org>
 
 	* stage2/builtins.c (geometry_func): Attempt to read the first

stage2/builtins.c

@@ -217,7 +217,28 @@ boot_func (char *arg, int flags)
       
       gateA20 (0);
       boot_drive = saved_drive;
-      chain_stage1 (0, BOOTSEC_LOCATION, BOOTSEC_LOCATION - 16);
+      
+      /* Copy the boot partition information to the chain-loader, if
+	 BOOT_DRIVE is a hard disk drive.  */
+      if (boot_drive & 0x80)
+	{
+	  /* Read the MBR here, because it might be modified
+	     after opening the partition.  */
+	  if (! rawread (boot_drive, boot_part_offset,
+			 0, SECTOR_SIZE, (char *) SCRATCHADDR))
+	    {
+	      /* This should never happen.  */
+	      errnum = ERR_READ;
+	      return 0;
+	    }
+
+	  /* Need only the partition table.  */
+	  grub_memmove ((char *) BOOTSEC_LOCATION + BOOTSEC_PART_OFFSET,
+			(char *) SCRATCHADDR + BOOTSEC_PART_OFFSET,
+			BOOTSEC_PART_LENGTH);
+	}
+      
+      chain_stage1 (0, BOOTSEC_LOCATION, boot_part_addr);
       break;
 
     case KERNEL_TYPE_MULTIBOOT:

stage2/disk_io.c

@@ -67,6 +67,13 @@ struct fsys_entry fsys_table[NUM_FSYS + 1] =
 unsigned long current_drive = 0xFF;
 unsigned long current_partition;
 
+#ifndef STAGE1_5
+/* The register ESI should contain the address of the partition to be
+   used for loading a chain-loader when chain-loading the loader.  */
+unsigned long boot_part_addr;
+unsigned long boot_part_offset;
+#endif
+
 /*
  *  Global variables describing details of the filesystem
  */
@@ -451,16 +458,16 @@ check_BSD_parts (int flags)
   return 0;
 }
 
-
 #ifndef STAGE1_5
-static char cur_part_desc[16];
+static unsigned long cur_part_offset;
+static unsigned long cur_part_addr;
 #endif
 
 int
 real_open_partition (int flags)
 {
-  char mbr_buf[SECTOR_SIZE];
   int i, part_no, slice_no, ext = 0;
+  char mbr_buf[SECTOR_SIZE];
   
 #ifndef STAGE1_5
   /* network drive */
@@ -527,9 +534,8 @@ real_open_partition (int flags)
 	      part_start = part_offset + PC_SLICE_START (mbr_buf, i);
 	      part_length = PC_SLICE_LENGTH (mbr_buf, i);
 #ifndef STAGE1_5
-	      grub_memmove (cur_part_desc,
+	      cur_part_offset = part_offset;
-			    mbr_buf + PC_SLICE_OFFSET + (i << 4),
+	      cur_part_addr = BOOTSEC_LOCATION + PC_SLICE_OFFSET + (i << 4);
-			    16);
 #endif
 
 	      /*
@@ -848,10 +854,9 @@ set_bootdev (int hdbias)
 {
   int i, j;
 
-  /*
+  /* Save the boot partition for chain-loading.  */
-   *  Set chainloader boot device.
+  boot_part_offset = cur_part_offset;
-   */
+  boot_part_addr = cur_part_addr;
-  memmove ((char *) (BOOTSEC_LOCATION - 16), cur_part_desc, 16);
   
   /*
    *  Set BSD boot device.

stage2/shared.h

@@ -415,6 +415,8 @@ typedef enum
 
 extern unsigned long install_partition;
 extern unsigned long boot_drive;
+extern unsigned long boot_part_addr;
+extern unsigned long boot_part_offset;
 extern char version_string[];
 extern char config_file[];