[linuxsh-dev] Memory map for loading kernel

[NIIBE Y. <gn...@ch...>]

I'd like to reserve 64KB for the second storage loader (see the patch
below).  I think that Takeshi cares...

I'm thinking of following memory map:


	+------------------+  0
	|*                 |       1 page for ROM monitor use
	|                  |
	|                  |
	|                  |
	|                  |
	|                  |
	+------------------+  2MB
	|****************  |       16 page for loader use
	|                  |
	|                  |
	|                  |
	:                  :
	:                  :
	|                  |
	|                  |
	+------------------+

The boot sequence is like follows:

  (1) ROM IPL uses the first page for working area (and stack).

  (2) IPL reads MBR on disk into the memory at 2MB, and jumps to it.

  (3) The program within MBR (first stage loader) reads the second
      stage loader and boot information (kernel map, initrd map,
      keyboard translation table command line args, and such) into
      the memory around 2MB.

  (4) Control goes to the seond loader and it reads kernel images
      into the memory above (> 2MB), and jumps to it.

  (5) zImage expand itself into the memory, and jumps to it.


2000-07-11  NIIBE Yutaka  <gn...@m1...>

	* arch/sh/boot/compressed/Makefile (ZIMAGE_OFFSET): Add more
	64KB for the use of program loader which load the image from
	second storage.

Index: arch/sh/boot/compressed/Makefile
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/boot/compressed/Makefile,v
retrieving revision 1.3
diff -u -r1.3 Makefile
--- arch/sh/boot/compressed/Makefile	2000/06/10 21:45:10	1.3
+++ arch/sh/boot/compressed/Makefile	2000/07/11 06:30:23
@@ -14,7 +14,7 @@
 #
 # ZIMAGE_OFFSET is the load offset of the compression loader
 #
-ZIMAGE_OFFSET = $(shell printf "0x%8x" $$[0x80000000+0x$(CONFIG_MEMORY_START)+0x200000])
+ZIMAGE_OFFSET = $(shell printf "0x%8x" $$[0x80000000+0x$(CONFIG_MEMORY_START)+0x200000+0x10000])
 
 ZLINKFLAGS = -Ttext $(ZIMAGE_OFFSET) $(ZLDFLAGS)
 
--