Add experimental code to self-relocate vmlinuz on e.g. brcm

This is needed for the following reason: our memory layout
looks like this:

| |vmlinux              |    |CFE| *                 |
| |                     |vmlinuz    |                |
   ^

Since CFE can only load to the spot marked with ‘^’ anyway,
we load vmlinub.elf there which is basically a big rodata
blob containing vmlinuz and minimal code moving it to the
location pointed with vmlinuz above. Another solution would
be to use CFE’s “boot -raw” to place it on the location marked
with ‘*’ above (but the CFE location and size are dynamic, and
since it insists on loading to 0x80001000 anyway, this point
is virtually moot).

Signed-off-by: Thorsten Glaser <tg@mirbsd.org>

target/linux/patches/2.6.36/zboot-brcm-reloc.patch

@@ -0,0 +1,196 @@
+--- /dev/null	Thu Jan  6 00:14:18 2011
++++ linux-2.6.36/arch/mips/boot/compressed/selfreloc.lds.S	Wed Jan  5 23:52:43 2011
+@@ -0,0 +1,39 @@
++/*-
++ * written 2010 by Thorsten Glaser <tg@debian.org> based on
++ * arch/mips/kernel/vmlinux.lds and arch/mips/boot/compressed/ld.script
++ */
++
++#include <asm/asm-offsets.h>
++#include <asm/page.h>
++#include <asm-generic/vmlinux.lds.h>
++
++#undef mips
++#define mips mips
++OUTPUT_ARCH(mips)
++ENTRY(selfreloc_start)
++PHDRS {
++	text PT_LOAD FLAGS(7);	/* RWX */
++}
++SECTIONS
++{
++	. = VMLINUX_LOAD_ADDRESS;
++	.text : {
++		*(.text)
++		*(.text.*)
++		*(.rodata)
++		*(.rodata.*)
++		*(.data)
++		*(.data.*)
++		*(.bss)
++		*(.bss.*)
++	} :text
++	/DISCARD/ : {
++		*(.MIPS.options)
++		*(.options)
++		*(.pdr)
++		*(.reginfo)
++		*(.comment)
++		*(.note)
++		*(.gnu.attributes)
++	}
++}
+--- /dev/null	Thu Jan  6 00:14:22 2011
++++ linux-2.6.36/arch/mips/boot/compressed/selfreloc1.S	Wed Jan  5 23:22:30 2011
+@@ -0,0 +1,48 @@
++/*-
++ * written 2011 by Thorsten Glaser <tg@freewrt.org> based on
++ * arch/mips/boot/compressed/head.S
++ */
++
++#include <asm/asm.h>
++#include <asm/regdef.h>
++
++	.set noreorder
++	.cprestore
++
++	.globl	selfreloc_move
++
++	.text
++	LEAF(selfreloc_start)
++selfreloc_start:
++	/* Save boot rom start args */
++	move	s0, a0
++	move	s1, a1
++	move	s2, a2
++	move	s3, a3
++
++	PTR_LI	a0, VMLINUZ_LOAD_ADDRESS
++	PTR_LA  sp, (.stack + 2048)  /* stack address */
++
++	PTR_LA	ra, 2f
++	PTR_LA	k0, selfreloc_move
++	jr	k0
++	 nop
++2:
++	move	a0, s0
++	move	a1, s1
++	move	a2, s2
++	move	a3, s3
++	PTR_LI	k0, VMLINUZ_LOAD_ADDRESS
++	jr	k0
++	 nop
++3:
++	b	3b
++	 nop
++	END(selfreloc_start)
++
++	.globl	imgbeg
++imgbeg:	.incbin	"vmlinuz.bin"
++	.globl	imgend
++imgend:
++
++	.comm .stack,2048,4
+--- /dev/null	Thu Jan  6 00:14:26 2011
++++ linux-2.6.36/arch/mips/boot/compressed/selfreloc2.c	Wed Jan  5 23:34:00 2011
+@@ -0,0 +1,39 @@
++/* written 2011 by Thorsten Glaser <tg@mirbsd.org> */
++
++extern unsigned char imgbeg, imgend;
++
++/* debug interfaces */
++extern void puts(const char *);
++extern void puthex(unsigned long long);
++
++void selfreloc_move(unsigned char *);
++
++/*
++ * Note: we assume we are loaded to VMLINUX_LOAD_ADDRESS,
++ * the range between it and our end-of-file doesn't over-
++ * lap VMLINUZ_LOAD_ADDRESS, we need to relocate the code
++ * there and jump to its first byte.
++ */
++
++void
++selfreloc_move(unsigned char *dst /* VMLINUZ_LOAD_ADDRESS */)
++{
++	unsigned char *src;
++	unsigned long len;
++
++	puts("in selfreloc_move from ");
++	puthex((unsigned long)&imgbeg);
++	puts(":");
++	puthex((unsigned long)&imgend);
++	puts(" to ");
++	puthex((unsigned long)dst);
++	puts(" ...");
++
++	src = &imgbeg;
++	len = (unsigned long)(&imgend) - (unsigned long)(&imgbeg);
++
++	while (len--)
++		*dst++ = *src++;
++
++	puts("done\n");
++}
+--- linux-2.6.36/arch/mips/boot/compressed/Makefile~	Wed Jan  5 21:26:40 2011
++++ linux-2.6.36/arch/mips/boot/compressed/Makefile	Wed Jan  5 23:35:58 2011
+@@ -28,12 +28,14 @@ KBUILD_AFLAGS := $(LINUXINCLUDE) $(KBUIL
+ targets := head.o decompress.o dbg.o uart-16550.o uart-alchemy.o
+ 
+ # decompressor objects (linked with vmlinuz)
+-vmlinuzobjs-y := $(obj)/head.o $(obj)/decompress.o $(obj)/dbg.o
++vmlinuzobjs-y := $(obj)/head.o $(obj)/decompress.o
++vmlinuz-dbg-objs-y := $(obj)/dbg.o
+ 
+ ifdef CONFIG_DEBUG_ZBOOT
+-vmlinuzobjs-$(CONFIG_SYS_SUPPORTS_ZBOOT_UART16550) += $(obj)/uart-16550.o
+-vmlinuzobjs-$(CONFIG_MIPS_ALCHEMY)		   += $(obj)/uart-alchemy.o
++vmlinuz-dbg-objs-$(CONFIG_SYS_SUPPORTS_ZBOOT_UART16550) += $(obj)/uart-16550.o
++vmlinuz-dbg-objs-$(CONFIG_MIPS_ALCHEMY)		   += $(obj)/uart-alchemy.o
+ endif
++vmlinuzobjs-y += $(vmlinuz-dbg-objs-y)
+ 
+ targets += vmlinux.bin
+ OBJCOPYFLAGS_vmlinux.bin := $(OBJCOPYFLAGS) -O binary -R .comment -S
+@@ -106,4 +107,12 @@ OBJCOPYFLAGS_vmlinuz.srec := $(OBJCOPYFL
+ vmlinuz.srec: vmlinuz
+ 	$(call cmd,objcopy)
+ 
+-clean-files := $(objtree)/vmlinuz $(objtree)/vmlinuz.{32,ecoff,bin,srec}
++AFLAGS_selfreloc1.o := -DVMLINUZ_LOAD_ADDRESS=$(VMLINUZ_LOAD_ADDRESS)
++arch/mips/boot/compressed/selfreloc1.o: arch/mips/boot/compressed/selfreloc1.S vmlinuz.bin
++
++CPPFLAGS_selfreloc.lds := $(KBUILD_CFLAGS)
++
++vmlinub.elf: arch/mips/boot/compressed/selfreloc1.o arch/mips/boot/compressed/selfreloc2.o arch/mips/boot/compressed/selfreloc.lds $(vmlinuz-dbg-objs-y)
++	$(LD) $(LDFLAGS) -T arch/mips/boot/compressed/selfreloc.lds arch/mips/boot/compressed/selfreloc1.o arch/mips/boot/compressed/selfreloc2.o $(vmlinuz-dbg-objs-y) -o $@
++
++clean-files := $(objtree)/vmlinuz $(objtree)/vmlinuz.{32,ecoff,bin,srec} $(objtree)/vmlinub.elf $(objtree)/arch/mips/boot/compressed/selfreloc{{1,2}.o,.lds}
+--- linux-2.6.36/arch/mips/Makefile~	Wed Jan  5 20:26:12 2011
++++ linux-2.6.36/arch/mips/Makefile	Wed Jan  5 22:41:38 2011
+@@ -79,6 +79,7 @@ endif
+ all-$(CONFIG_BOOT_ELF32)	:= $(vmlinux-32)
+ all-$(CONFIG_BOOT_ELF64)	:= $(vmlinux-64)
+ all-$(CONFIG_SYS_SUPPORTS_ZBOOT)+= vmlinuz
++all-$(CONFIG_BCM47XX)		+= vmlinub.elf
+ 
+ #
+ # GCC uses -G 0 -mabicalls -fpic as default.  We don't want PIC in the kernel
+@@ -285,7 +286,7 @@ vmlinux.bin vmlinux.ecoff vmlinux.srec: 
+ 	$(Q)$(MAKE) $(build)=arch/mips/boot VMLINUX=$(vmlinux-32) arch/mips/boot/$@
+ 
+ # boot/compressed
+-vmlinuz vmlinuz.bin vmlinuz.ecoff vmlinuz.srec: $(vmlinux-32) FORCE
++vmlinuz vmlinuz.bin vmlinuz.ecoff vmlinuz.srec vmlinub.elf: $(vmlinux-32) FORCE
+ 	$(Q)$(MAKE) $(build)=arch/mips/boot/compressed \
+ 	   VMLINUX_LOAD_ADDRESS=$(load-y) 32bit-bfd=$(32bit-bfd) $@
+ 
+@@ -322,6 +323,7 @@ define archhelp
+ 	echo '  vmlinuz.ecoff        - ECOFF zboot image'
+ 	echo '  vmlinuz.bin          - Raw binary zboot image'
+ 	echo '  vmlinuz.srec         - SREC zboot image'
++	echo '  vmlinub.elf          - ELF self-relocating zboot image'
+ 	echo
+ 	echo '  These will be default as apropriate for a configured platform.'
+ endef