This changeset adds a new feature to ARM - the ability to load the

kernel zImage almost anywhere in RAM and call it directly, without
having to copy it to a specific address.  This removes a dependency
between the boot loader and the kernel.

arch/arm/Config.help

@@ -836,3 +836,15 @@ CONFIG_DEBUG_BUGVERBOSE
   of the BUG call as well as the EIP and oops trace.  This aids
   debugging but costs about 70-100K of memory.
 
+CONFIG_ZBOOT_ROM
+  Say Y here if you intend to execute your compressed kernel image (zImage)
+  directly from ROM or flash.  If unsure, say N.
+
+CONFIG_ZBOOT_ROM_TEXT
+  The base address for zImage.  Unless you have special requirements, you
+  should not change this value.
+
+CONFIG_ZBOOT_ROM_BSS
+  The base address of 64KiB of read/write memory, which must be available
+  while the decompressor is running.  Unless you have special requirements,
+  you should not change this value.

arch/arm/boot/Makefile

@@ -5,31 +5,31 @@
 # License.  See the file "COPYING" in the main directory of this archive
 # for more details.
 #
-# Copyright (C) 1995-2000 Russell King
+# Copyright (C) 1995-2002 Russell King
 #
 
 SYSTEM	=$(TOPDIR)/vmlinux
 
 ifeq ($(CONFIG_CPU_26),y)
-ZTEXTADDR	 = 0x02080000
+ZRELADDR	 = 0x02080000
 PARAMS_PHYS	 = 0x0207c000
 INITRD_PHYS	 = 0x02180000
 INITRD_VIRT	 = 0x02180000
 endif
 
 ifeq ($(CONFIG_ARCH_RPC),y)
-ZTEXTADDR	 = 0x10008000
+ZRELADDR	 = 0x10008000
 PARAMS_PHYS	 = 0x10000100
 INITRD_PHYS	 = 0x18000000
 INITRD_VIRT	 = 0xc8000000
 endif
 
 ifeq ($(CONFIG_ARCH_CLPS7500),y)
-ZTEXTADDR	 = 0x10008000
+ZRELADDR	 = 0x10008000
 endif
 
 ifeq ($(CONFIG_ARCH_EBSA110),y)
-ZTEXTADDR	 = 0x00008000
+ZRELADDR	 = 0x00008000
 PARAMS_PHYS	 = 0x00000400
 INITRD_PHYS	 = 0x00800000
 INITRD_VIRT	 = 0xc0800000
@@ -41,41 +41,34 @@ ZRELADDR	 = 0x08008000
 endif
 
 ifeq ($(CONFIG_FOOTBRIDGE),y)
-ZTEXTADDR	 = 0x00008000
+ZRELADDR	 = 0x00008000
 PARAMS_PHYS	 = 0x00000100
 INITRD_PHYS	 = 0x00800000
 INITRD_VIRT	 = 0xc0800000
 endif
 
 ifeq ($(CONFIG_ARCH_INTEGRATOR),y)
-ZTEXTADDR	 = 0x00008000
+ZRELADDR	 = 0x00008000
 PARAMS_PHYS	 = 0x00000100
 INITRD_PHYS	 = 0x00800000
 INITRD_VIRT	 = 0xc0800000
 endif
 
 ifeq ($(CONFIG_ARCH_CAMELOT),y)
-ZTEXTADDR	 = 0x00008000
+ZRELADDR	 = 0x00008000
 endif
 
 ifeq ($(CONFIG_ARCH_NEXUSPCI),y)
-ZTEXTADDR	 = 0x40008000
+ZRELADDR	 = 0x40008000
 endif
 
 ifeq ($(CONFIG_ARCH_L7200),y)
-# RAM based kernel
-#ZTEXTADDR	 = 0xf0400000
-#ZRELADDR	 = 0xf0008000
-
-# FLASH based kernel
-ZTEXTADDR	 = 0x00010000
 ZRELADDR	 = 0xf0008000
-ZBSSADDR	 = 0xf03e0000
 endif
 
 # The standard locations for stuff on CLPS711x type processors
 ifeq ($(CONFIG_ARCH_CLPS711X),y)
-ZTEXTADDR	 = 0xc0028000
+ZRELADDR	 = 0xc0028000
 PARAMS_PHYS	 = 0xc0000100
 endif
 
@@ -90,60 +83,40 @@ INITRD_VIRT	 = 0xc0300000
 endif
 
 ifeq ($(CONFIG_ARCH_SA1100),y)
-ZTEXTADDR	 = 0xc0008000
 ZRELADDR	 = 0xc0008000
-ifeq ($(CONFIG_SA1100_VICTOR),y)
-  ZTEXTADDR	 = 0x00002000
-  ZBSSADDR	 = 0xc0200000
-endif
-ifeq ($(CONFIG_SA1100_SHERMAN),y)
-  ZTEXTADDR      = 0x00050000   
-  ZBSSADDR       = 0xc0200000
-endif
-ifeq ($(CONFIG_SA1100_GRAPHICSCLIENT),y)
-  ZTEXTADDR	 = 0xC0200000
-endif
-ifeq ($(CONFIG_SA1100_GRAPHICSMASTER),y)
-  ZTEXTADDR	 = 0xC0400000
-endif
-ifeq ($(CONFIG_SA1100_ADSBITSY),y)
-  ZTEXTADDR	 = 0xC0400000
-endif
-ifeq ($(CONFIG_SA1100_YOPY),y)
-  ZTEXTADDR      = 0x00080000
-  ZBSSADDR       = 0xc0200000
-endif
+# No defconfig file to move this into...
+#ifeq ($(CONFIG_SA1100_YOPY),y)
+#  ZTEXTADDR      = 0x00080000
+#  ZBSSADDR       = 0xc0200000
+#endif
 ifeq ($(CONFIG_SA1111),y)
   ZRELADDR	 = 0xc0208000
 endif
 endif
 
 ifeq ($(CONFIG_ARCH_ANAKIN),y)
-ZTEXTADDR	 = 0x20008000
+ZRELADDR	 = 0x20008000
 endif
 
 ifeq ($(CONFIG_ARCH_IQ80310),y)
 ZRELADDR	 = 0xa0008000
-
-# for serial upload
-ZTEXTADDR	 = 0xa1008000
-
-# for direct flash execution
-# ZTEXTADDR	 = 0x00060000
-# ZBSSADDR	 = 0xa1008000
 endif
 
 ifeq ($(CONFIG_ARCH_ADIFCC),y)
 ZRELADDR	 = 0xc0008000
-ZTEXTADDR	 = 0xc1000000
 endif
 
 #
-# If you don't define ZRELADDR above,
-# then it defaults to ZTEXTADDR
+# We now have a PIC decompressor implementation.  Decompressors running
+# from RAM should not define ZTEXTADDR.  Decompressors running directly
+# from ROM or Flash must define ZTEXTADDR (preferably via the config)
 #
-ifeq ($(ZRELADDR),)
-ZRELADDR	= $(ZTEXTADDR)
+ifeq ($(CONFIG_ZBOOT_ROM),y)
+ZTEXTADDR	=0x$(CONFIG_ZBOOT_ROM_TEXT)
+ZBSSADDR	=0x$(CONFIG_ZBOOT_ROM_BSS)
+else
+ZTEXTADDR	=0
+ZBSSADDR	=ALIGN(4)
 endif
 
 export	SYSTEM ZTEXTADDR ZBSSADDR ZRELADDR INITRD_PHYS INITRD_VIRT PARAMS_PHYS

arch/arm/boot/compressed/Makefile

@@ -9,7 +9,7 @@
 
 HEAD		 = head.o
 OBJS		 = misc.o
-CFLAGS		 = $(CPPFLAGS) -O2 -DSTDC_HEADERS $(CFLAGS_BOOT)
+CFLAGS		 = $(CPPFLAGS) -O2 -DSTDC_HEADERS $(CFLAGS_BOOT) -fpic
 FONTC		 = $(TOPDIR)/drivers/video/font_acorn_8x8.c
 ZLDFLAGS	 = -p -X -T vmlinux.lds
 
@@ -65,13 +65,7 @@ ifeq ($(CONFIG_CPU_XSCALE),y)
 OBJS		+= head-xscale.o
 endif
 
-SEDFLAGS	= s/TEXT_START/$(ZTEXTADDR)/;s/LOAD_ADDR/$(ZRELADDR)/;
-
-ifneq ($(ZBSSADDR),)
-SEDFLAGS	+= s/BSS_START/$(ZBSSADDR)/
-else
-SEDFLAGS	+= s/BSS_START/ALIGN(4)/
-endif
+SEDFLAGS	= s/TEXT_START/$(ZTEXTADDR)/;s/LOAD_ADDR/$(ZRELADDR)/;s/BSS_START/$(ZBSSADDR)/
 
 LIBGCC		:= $(shell $(CC) $(CFLAGS) --print-libgcc-file-name)
 

arch/arm/boot/compressed/head-clps7500.S

@@ -13,7 +13,7 @@
 		/* This branch is taken if the CPU memory width matches the
 		   actual device in use.  The default at power on is 16 bits
 		   so we must be prepared for a mismatch. */
-		.section ".start", #alloc, #execinstr
+		.section ".start", "ax"
 2:
 		b	1f
 		.word	0xffff

arch/arm/boot/compressed/head-epxa10db.S

 #include <asm/mach-types.h>
 #include <asm/arch/excalibur.h>
 
-		.section	".start", #alloc, #execinstr
+		.section	".start", "ax"
 		mov	r7, #MACH_TYPE_CAMELOT

arch/arm/boot/compressed/head-ftvpci.S

@@ -13,7 +13,7 @@
  * 2 of the License, or (at your option) any later version.
  */
 
-	.section        ".start", #alloc, #execinstr
+	.section        ".start", "ax"
 ftv_start:
 	mcr	p15, 0, r0, c7, c5, 0		@ flush I cache
 	mrc	p15, 0, r0, c1, c0

arch/arm/boot/compressed/head-integrator.S

 #include <asm/mach-types.h>
 
-		.section	".start", #alloc, #execinstr
+		.section	".start", "ax"
 		mov	r7, #MACH_TYPE_INTEGRATOR

arch/arm/boot/compressed/head-l7200.S

@@ -13,7 +13,7 @@
 #error What am I doing here...
 #endif
 
-		.section        ".start", #alloc, #execinstr
+		.section        ".start", "ax"
 
 __L7200_start:
 		mov	r0, #0x00100000		@ FLASH address of initrd

arch/arm/boot/compressed/head-netwinder.S

 /*
  *  linux/arch/arm/boot/compressed/head-netwinder.S
  *
- *  Copyright (C) 2000 Russell King
+ *  Copyright (C) 2000-2002 Russell King
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
-#define K(a,b,c)	((a) << 24 | (b) << 12 | (c))
+		.section	".start", "ax"
 
-		.section	".start", #alloc, #execinstr
-
-		/*
-		 * check to see if we are running from the correct address.
-		 * If not, we move ourselves in a two stage process.  Firstly,
-		 * we copy the start of the kernel (which includes this code)
-		 * to 0x8000, and then jump to this code to continue with the
-		 * rest (since this code will get overwritten).
-		 */
-		adr	r2, 1f
-		ldmdb	r2, {r9, r10}
-		and	r3, r2, #0xc000
-		teq	r3, #0x8000	@ correctly located?
-		beq	2f		@ skip this code
-		bic	r3, r2, #0xc000
-		orr	r3, r3, #0x8000
-		mov	r0, r3		@ new address if '1'
-		mov	r4, #64		@ number of bytes to copy
-		sub	r5, r10, r9	@ total number of bytes to copy
-		b	1f
-
-		.word	_start
-		.word	__bss_start
-
-1:
-		.rept	4
-		ldmia	r2!, {r6, r9, r10, r11}
-		stmia	r3!, {r6, r9, r10, r11}
-		.endr
-		subs	r4, r4, #64
-		bcs	1b
-		movs	r4, r5		@ remaining length
-		mov	r5, #0		@ no more to copy
-		movne	pc, r0		@ jump back to 1 (in the newly copied
-					@ code)
-		mov	r7, #5		@ only here to fix NeTTroms which dont
-		mov	r8, #2 << 24		@ scheduled for removal in 2.5.xx
-		orr	r8, r8, #5 << 12
-2:
+		mov	r7, #5
+		mov	r8, #0

arch/arm/boot/compressed/head-sa1100.S

@@ -11,7 +11,7 @@
 #include <linux/linkage.h>
 #include <asm/mach-types.h>
 
-		.section        ".start", #alloc, #execinstr
+		.section        ".start", "ax"
 
 __SA1100_start:
 

arch/arm/boot/compressed/head-shark.S

@@ -16,7 +16,7 @@
 
 #include <asm/assembler.h>
 	
-		.section	".start", #alloc, #execinstr
+		.section	".start", "ax"
 
 		b	__beginning
 	

arch/arm/boot/compressed/head-xscale.S

@@ -9,7 +9,7 @@
 #include <linux/linkage.h>
 #include <asm/mach-types.h>
 
-		.section        ".start", #alloc, #execinstr
+		.section        ".start", "ax"
 
 __XScale_start:
 

arch/arm/boot/compressed/head.S

@@ -132,10 +132,28 @@ not_angel:
 		 */
 
 		.text
-1:		adr	r2, LC0
-		ldmia	r2, {r2, r3, r4, r5, sp}
+		adr	r0, LC0
+		ldmia	r0, {r1, r2, r3, r4, r5, r6, ip, sp}
+		subs	r0, r0, r1		@ calculate the delta offset
+
+		teq	r0, #0			@ if delta is zero, we're
+		beq	not_relocated		@ running at the address we
+						@ were linked at.
+
+		add	r2, r2, r0		@ different address, so we
+		add	r3, r3, r0		@ need to fix up various
+		add	r5, r5, r0		@ pointers.
+		add	r6, r6, r0
+		add	ip, ip, r0
+		add	sp, sp, r0
+
+1:		ldr	r1, [r6, #0]		@ relocate entries in the GOT
+		add	r1, r1, r0		@ table.  This fixes up the
+		str	r1, [r6], #4		@ C references.
+		cmp	r6, ip
+		blt	1b
 
-		mov	r0, #0
+not_relocated:	mov	r0, #0
 1:		str	r0, [r2], #4		@ clear bss
 		str	r0, [r2], #4
 		str	r0, [r2], #4
@@ -149,17 +167,26 @@ not_angel:
 		mov	r1, sp			@ malloc space above stack
 		add	r2, sp, #0x10000	@ 64k max
 
-		teq	r4, r5			@ will we overwrite ourselves?
-		moveq	r5, r2			@ decompress after image
-		movne	r5, r4			@ decompress to final location
+/*
+ * Check to see if we will overwrite ourselves.
+ *   r4 = final kernel address
+ *   r5 = start of this image
+ *   r2 = end of malloc space (and therefore this image)
+ * We basically want:
+ *   r4 >= r2 -> OK
+ *   r4 + image length <= r5 -> OK
+ */
+		cmp	r4, r2
+		bhs	wont_overwrite
+		add	r0, r4, #4096*1024	@ 4MB largest kernel size
+		cmp	r0, r5
+		bls	wont_overwrite
 
+		mov	r5, r2			@ decompress after malloc space
 		mov	r0, r5
 		mov	r3, r7
 		bl	SYMBOL_NAME(decompress_kernel)
 
-		teq	r4, r5			@ do we need to relocate
-		beq	call_kernel		@ the kernel?
-
 		add	r0, r0, #127
 		bic	r0, r0, #127		@ align the kernel length
 /*
@@ -184,12 +211,26 @@ not_angel:
 		bl	cache_clean_flush
 		add	pc, r5, r0		@ call relocation code
 
+/*
+ * We're not in danger of overwriting ourselves.  Do this the simple way.
+ *
+ * r4     = kernel execution address
+ * r7     = architecture ID
+ */
+wont_overwrite:	mov	r0, r4
+		mov	r3, r7
+		bl	SYMBOL_NAME(decompress_kernel)
+		b	call_kernel
+
 		.type	LC0, #object
-LC0:		.word	__bss_start
-		.word	_end
-		.word	_load_addr
-		.word	_start
-		.word	user_stack+4096
+LC0:		.word	LC0			@ r1
+		.word	__bss_start		@ r2
+		.word	_end			@ r3
+		.word	_load_addr		@ r4
+		.word	_start			@ r5
+		.word	_got_start		@ r6
+		.word	_got_end		@ r7
+		.word	user_stack+4096		@ r8
 		.size	LC0, . - LC0
 
 /*
@@ -518,5 +559,5 @@ memdump:	mov	r12, r0
 reloc_end:
 
 		.align
-		.section	".stack"
+		.section ".stack", "aw"
 user_stack:	.space	4096

arch/arm/boot/compressed/vmlinux.lds.in

@@ -35,29 +35,26 @@ SECTIONS
 
   _etext = .;
 
-  .data : {
-    *(.data)
-  }
-
+  _got_start = .;
+  .got			: { *(.got) }
+  _got_end = .;
+  .got.plt		: { *(.got.plt) }
+  .data			: { *(.data) }
   _edata = .;
 
   . = BSS_START;
   __bss_start = .;
-  .bss : {
-    *(.bss)
-  }
+  .bss			: { *(.bss) }
   _end = .;
 
-  .stack : {
-    *(.stack)
-  }
+  .stack (NOLOAD)	: { *(.stack) }
 
-  .stab 0 : { *(.stab) }
-  .stabstr 0 : { *(.stabstr) }
-  .stab.excl 0 : { *(.stab.excl) }
-  .stab.exclstr 0 : { *(.stab.exclstr) }
-  .stab.index 0 : { *(.stab.index) }
-  .stab.indexstr 0 : { *(.stab.indexstr) }
-  .comment 0 : { *(.comment) }
+  .stab 0		: { *(.stab) }
+  .stabstr 0		: { *(.stabstr) }
+  .stab.excl 0		: { *(.stab.excl) }
+  .stab.exclstr 0	: { *(.stab.exclstr) }
+  .stab.index 0		: { *(.stab.index) }
+  .stab.indexstr 0	: { *(.stab.indexstr) }
+  .comment 0		: { *(.comment) }
 }
 

arch/arm/config.in

@@ -433,6 +433,12 @@ else
    define_bool CONFIG_FIQ n
 fi
 
+# Compressed boot loader in ROM.  Yes, we really want to ask about
+# TEXT and BSS so we preserve their values in the config files.
+bool 'Compressed boot loader in ROM/flash' CONFIG_ZBOOT_ROM
+hex 'Compressed ROM boot loader base address' CONFIG_ZBOOT_ROM_TEXT 0
+hex 'Compressed ROM boot loader BSS address' CONFIG_ZBOOT_ROM_BSS 0
+
 if [ "$CONFIG_ARCH_SA1100" = "y" -o \
      "$CONFIG_ARCH_INTEGRATOR" = "y" ]; then
    dep_bool 'Support CPU clock change (EXPERIMENTAL)' CONFIG_CPU_FREQ $CONFIG_EXPERIMENTAL

arch/arm/def-configs/iq80310

@@ -139,6 +139,9 @@ CONFIG_ARM_THUMB=y
 #
 # General setup
 #
+CONFIG_ZBOOT_ROM=y
+CONFIG_ZBOOT_ROM_TEXT=0x00060000
+CONFIG_ZBOOT_ROM_BSS=0xa1008000
 CONFIG_PCI=y
 # CONFIG_ISA is not set
 # CONFIG_ISA_DMA is not set

arch/arm/def-configs/lusl7200

@@ -23,6 +23,9 @@ CONFIG_CPU_32=y
 # CONFIG_CPU_26 is not set
 CONFIG_CPU_32v4=y
 CONFIG_CPU_ARM720=y
+CONFIG_ZBOOT_ROM=y
+CONFIG_ZBOOT_ROM_TEXT=0x00010000
+CONFIG_ZBOOT_ROM_BSS=0xf03e0000
 # CONFIG_PCI is not set
 # CONFIG_ISA is not set
 # CONFIG_ISA_DMA is not set

arch/arm/def-configs/sherman

@@ -47,6 +47,9 @@ CONFIG_MODULES=y
 #
 # General setup
 #
+CONFIG_ZBOOT_ROM=y
+CONFIG_ZBOOT_ROM_TEXT=0x00050000
+CONFIG_ZBOOT_ROM_BSS=0xc0200000
 # CONFIG_NET is not set
 # CONFIG_SYSVIPC is not set
 # CONFIG_BSD_PROCESS_ACCT is not set

arch/arm/def-configs/victor

@@ -46,6 +46,9 @@ CONFIG_MODULES=y
 #
 # General setup
 #
+CONFIG_ZBOOT_ROM=y
+CONFIG_ZBOOT_ROM_TEXT=0x00002000
+CONFIG_ZBOOT_ROM_BSS=0xc0200000
 # CONFIG_NET is not set
 # CONFIG_SYSVIPC is not set
 # CONFIG_BSD_PROCESS_ACCT is not set