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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/arm/kernel/head-nommu.S
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/*

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 *  linux/arch/arm/kernel/head-nommu.S

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 *

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 *  Copyright (C) 1994-2002 Russell King

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 *  Copyright (C) 2003-2006 Hyok S. Choi

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 *

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 * This program is free software; you can redistribute it and/or modify

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 * it under the terms of the GNU General Public License version 2 as

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 * published by the Free Software Foundation.

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 *

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 *  Common kernel startup code (non-paged MM)

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 *

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 */

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#include <linux/linkage.h>

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#include <linux/init.h>

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#include <asm/assembler.h>

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#include <asm/ptrace.h>

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#include <asm/asm-offsets.h>

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#include <asm/thread_info.h>

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#include <asm/system.h>

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/*

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 * Kernel startup entry point.

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 * ---------------------------

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 *

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 * This is normally called from the decompressor code.  The requirements

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 * are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,

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 * r1 = machine nr.

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 *

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 * See linux/arch/arm/tools/mach-types for the complete list of machine

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 * numbers for r1.

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 *

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 */

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	__HEAD

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ENTRY(stext)

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	setmode	PSR_F_BIT | PSR_I_BIT | SVC_MODE, r9 @ ensure svc mode

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						@ and irqs disabled

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#ifndef CONFIG_CPU_CP15

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	ldr	r9, =CONFIG_PROCESSOR_ID

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#else

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	mrc	p15, 0, r9, c0, c0		@ get processor id

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#endif

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	bl	__lookup_processor_type		@ r5=procinfo r9=cpuid

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	movs	r10, r5				@ invalid processor (r5=0)?

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	beq	__error_p				@ yes, error 'p'

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	adr	lr, BSYM(__after_proc_init)	@ return (PIC) address

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 ARM(	add	pc, r10, #PROCINFO_INITFUNC	)

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 THUMB(	add	r12, r10, #PROCINFO_INITFUNC	)

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 THUMB(	mov	pc, r12				)

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ENDPROC(stext)

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/*

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 * Set the Control Register and Read the process ID.

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 */

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__after_proc_init:

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#ifdef CONFIG_CPU_CP15

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	/*

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	 * CP15 system control register value returned in r0 from

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	 * the CPU init function.

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	 */

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#ifdef CONFIG_ALIGNMENT_TRAP

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	orr	r0, r0, #CR_A

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#else

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	bic	r0, r0, #CR_A

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#endif

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#ifdef CONFIG_CPU_DCACHE_DISABLE

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	bic	r0, r0, #CR_C

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#endif

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#ifdef CONFIG_CPU_BPREDICT_DISABLE

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	bic	r0, r0, #CR_Z

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#endif

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#ifdef CONFIG_CPU_ICACHE_DISABLE

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	bic	r0, r0, #CR_I

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#endif

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#ifdef CONFIG_CPU_HIGH_VECTOR

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	orr	r0, r0, #CR_V

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#else

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	bic	r0, r0, #CR_V

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#endif

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	mcr	p15, 0, r0, c1, c0, 0		@ write control reg

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#endif /* CONFIG_CPU_CP15 */

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	b	__mmap_switched			@ clear the BSS and jump

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						@ to start_kernel

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ENDPROC(__after_proc_init)

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	.ltorg

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#include "head-common.S"

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