path: root/arch/arm/boot/compressed/head.S

/*
 *  linux/arch/arm/boot/compressed/head.S
 *
 *  Copyright (C) 1996-2002 Russell King
 *  Copyright (C) 2004 Hyok S. Choi (MPU support)
 *
 * 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.
 */
#include <linux/linkage.h>

/*
 * Debugging stuff
 *
 * Note that these macros must not contain any code which is not
 * 100% relocatable.  Any attempt to do so will result in a crash.
 * Please select one of the following when turning on debugging.
 */
#ifdef DEBUG

#if defined(CONFIG_DEBUG_ICEDCC)

#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V6K) || defined(CONFIG_CPU_V7)
		.macro	loadsp, rb, tmp
		.endm
		.macro	writeb, ch, rb
		mcr	p14, 0, \ch, c0, c5, 0
		.endm
#elif defined(CONFIG_CPU_XSCALE)
		.macro	loadsp, rb, tmp
		.endm
		.macro	writeb, ch, rb
		mcr	p14, 0, \ch, c8, c0, 0
		.endm
#else
		.macro	loadsp, rb, tmp
		.endm
		.macro	writeb, ch, rb
		mcr	p14, 0, \ch, c1, c0, 0
		.endm
#endif

#else

#include <mach/debug-macro.S>

		.macro	writeb,	ch, rb
		senduart \ch, \rb
		.endm

#if defined(CONFIG_ARCH_SA1100)
		.macro	loadsp, rb, tmp
		mov	\rb, #0x80000000	@ physical base address
#ifdef CONFIG_DEBUG_LL_SER3
		add	\rb, \rb, #0x00050000	@ Ser3
#else
		add	\rb, \rb, #0x00010000	@ Ser1
#endif
		.endm
#elif defined(CONFIG_ARCH_S3C24XX)
		.macro loadsp, rb, tmp
		mov	\rb, #0x50000000
		add	\rb, \rb, #0x4000 * CONFIG_S3C_LOWLEVEL_UART_PORT
		.endm
#else
		.macro	loadsp,	rb, tmp
		addruart \rb, \tmp
		.endm
#endif
#endif
#endif

		.macro	kputc,val
		mov	r0, \val
		bl	putc
		.endm

		.macro	kphex,val,len
		mov	r0, \val
		mov	r1, #\len
		bl	phex
		.endm

		.macro	debug_reloc_start
#ifdef DEBUG
		kputc	#'\n'
		kphex	r6, 8		/* processor id */
		kputc	#':'
		kphex	r7, 8		/* architecture id */
#ifdef CONFIG_CPU_CP15
		kputc	#':'
		mrc	p15, 0, r0, c1, c0
		kphex	r0, 8		/* control reg */
#endif
		kputc	#'\n'
		kphex	r5, 8		/* decompressed kernel start */
		kputc	#'-'
		kphex	r9, 8		/* decompressed kernel end  */
		kputc	#'>'
		kphex	r4, 8		/* kernel execution address */
		kputc	#'\n'
#endif
		.endm

		.macro	debug_reloc_end
#ifdef DEBUG
		kphex	r5, 8		/* end of kernel */
		kputc	#'\n'
		mov	r0, r4
		bl	memdump		/* dump 256 bytes at start of kernel */
#endif
		.endm

		.section ".start", #alloc, #execinstr
/*
 * sort out different calling conventions
 */
		.align
		.arm				@ Always enter in ARM state
start:
		.type	start,#function
		.rept	7
		mov	r0, r0
		.endr
   ARM(		mov	r0, r0		)
   ARM(		b	1f		)
 THUMB(		adr	r12, BSYM(1f)	)
 THUMB(		bx	r12		)

		.word	0x016f2818		@ Magic numbers to help the loader
		.word	start			@ absolute load/run zImage address
		.word	_edata			@ zImage end address
 THUMB(		.thumb			)
1:		mov	r7, r1			@ save architecture ID
		mov	r8, r2			@ save atags pointer

#ifndef __ARM_ARCH_2__
		/*
		 * Booting from Angel - need to enter SVC mode and disable
		 * FIQs/IRQs (numeric definitions from angel arm.h source).
		 * We only do this if we were in user mode on entry.
		 */
		mrs	r2, cpsr		@ get current mode
		tst	r2, #3			@ not user?
		bne	not_angel
		mov	r0, #0x17		@ angel_SWIreason_EnterSVC
 ARM(		swi	0x123456	)	@ angel_SWI_ARM
 THUMB(		svc	0xab		)	@ angel_SWI_THUMB
not_angel:
		mrs	r2, cpsr		@ turn off interrupts to
		orr	r2, r2, #0xc0		@ prevent angel from running
		msr	cpsr_c, r2
#else
		teqp	pc, #0x0c000003		@ turn off interrupts
#endif

		/*
		 * Note that some cache flushing and other stuff may
		 * be needed here - is there an Angel SWI call for this?
		 */

		/*
		 * some architecture specific code can be inserted
		 * by the linker here, but it should preserve r7, r8, and r9.
		 */

		.text

#ifdef CONFIG_AUTO_ZRELADDR
		@ determine final kernel image address
		mov	r4, pc
		and	r4, r4, #0xf8000000
		add	r4, r4, #TEXT_OFFSET
#else
		ldr	r4, =zreladdr
#endif

		bl	cache_on

restart:	adr	r0, LC0
		ldmia	r0, {r1, r2, r3, r6, r10, r11, r12}
		ldr	sp, [r0, #28]

		/*
		 * We might be running at a different address.  We need
		 * to fix up various pointers.
		 */
		sub	r0, r0, r1		@ calculate the delta offset
		add	r6, r6, r0		@ _edata
		add	r10, r10, r0		@ inflated kernel size location

		/*
		 * The kernel build system appends the size of the
		 * decompressed kernel at the end of the compressed data
		 * in little-endian form.
		 */
		ldrb	r9, [r10, #0]
		ldrb	lr, [r10, #1]
		orr	r9, r9, lr, lsl #8
		ldrb	lr, [r10, #2]
		ldrb	r10, [r10, #3]
		orr	r9, r9, lr, lsl #16
		orr	r9, r9, r10, lsl #24

#ifndef CONFIG_ZBOOT_ROM
		/* malloc space is above the relocated stack (64k max) */
		add	sp, sp, r0
		add	r10, sp, #0x10000
#else
		/*
		 * With ZBOOT_ROM the bss/stack is non relocatable,
		 * but someone could still run this code from RAM,
		 * in which case our reference is _edata.
		 */
		mov	r10, r6
#endif

		mov	r5, #0			@ init dtb size to 0
#ifdef CONFIG_ARM_APPENDED_DTB
/*
 *   r0  = delta
 *   r2  = BSS start
 *   r3  = BSS end
 *   r4  = final kernel address
 *   r5  = appended dtb size (still unknown)
 *   r6  = _edata
 *   r7  = architecture ID
 *   r8  = atags/device tree pointer
 *   r9  = size of decompressed image
 *   r10 = end of this image, including  bss/stack/malloc space if non XIP
 *   r11 = GOT start
 *   r12 = GOT end
 *   sp  = stack pointer
 *
 * if there are device trees (dtb) appended to zImage, advance r10 so that the
 * dtb data will get relocated along with the kernel if necessary.
 */

		ldr	lr, [r6, #0]
#ifndef __ARMEB__
		ldr	r1, =0xedfe0dd0		@ sig is 0xd00dfeed big endian
#else
		ldr	r1, =0xd00dfeed
#endif
		cmp	lr, r1
		bne	dtb_check_done		@ not found

#ifdef CONFIG_ARM_ATAG_DTB_COMPAT
		/*
		 * OK... Let's do some funky business here.
		 * If we do have a DTB appended to zImage, and we do have
		 * an ATAG list around, we want the later to be translated
		 * and folded into the former here.  To be on the safe side,
		 * let's temporarily move  the stack away into the malloc
		 * area.  No GOT fixup has occurred yet, but none of the
		 * code we're about to call uses any global variable.
		*/
		add	sp, sp, #0x10000
		stmfd	sp!, {r0-r3, ip, lr}
		mov	r0, r8
		mov	r1, r6
		sub