1/*
2 *  linux/arch/arm/kernel/head-nommu.S
3 *
4 *  Copyright (C) 1994-2002 Russell King
5 *  Copyright (C) 2003-2006 Hyok S. Choi
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 *  Common kernel startup code (non-paged MM)
12 *
13 */
14#include <linux/linkage.h>
15#include <linux/init.h>
16
17#include <asm/assembler.h>
18#include <asm/ptrace.h>
19#include <asm/asm-offsets.h>
20#include <asm/cp15.h>
21#include <asm/thread_info.h>
22
23/*
24 * Kernel startup entry point.
25 * ---------------------------
26 *
27 * This is normally called from the decompressor code.  The requirements
28 * are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
29 * r1 = machine nr.
30 *
31 * See linux/arch/arm/tools/mach-types for the complete list of machine
32 * numbers for r1.
33 *
34 */
35	.arm
36
37	__HEAD
38ENTRY(stext)
39
40 THUMB(	adr	r9, BSYM(1f)	)	@ Kernel is always entered in ARM.
41 THUMB(	bx	r9		)	@ If this is a Thumb-2 kernel,
42 THUMB(	.thumb			)	@ switch to Thumb now.
43 THUMB(1:			)
44
45	setmode	PSR_F_BIT | PSR_I_BIT | SVC_MODE, r9 @ ensure svc mode
46						@ and irqs disabled
47#ifndef CONFIG_CPU_CP15
48	ldr	r9, =CONFIG_PROCESSOR_ID
49#else
50	mrc	p15, 0, r9, c0, c0		@ get processor id
51#endif
52	bl	__lookup_processor_type		@ r5=procinfo r9=cpuid
53	movs	r10, r5				@ invalid processor (r5=0)?
54	beq	__error_p				@ yes, error 'p'
55
56	adr	lr, BSYM(__after_proc_init)	@ return (PIC) address
57 ARM(	add	pc, r10, #PROCINFO_INITFUNC	)
58 THUMB(	add	r12, r10, #PROCINFO_INITFUNC	)
59 THUMB(	mov	pc, r12				)
60ENDPROC(stext)
61
62/*
63 * Set the Control Register and Read the process ID.
64 */
65__after_proc_init:
66#ifdef CONFIG_CPU_CP15
67	/*
68	 * CP15 system control register value returned in r0 from
69	 * the CPU init function.
70	 */
71#ifdef CONFIG_ALIGNMENT_TRAP
72	orr	r0, r0, #CR_A
73#else
74	bic	r0, r0, #CR_A
75#endif
76#ifdef CONFIG_CPU_DCACHE_DISABLE
77	bic	r0, r0, #CR_C
78#endif
79#ifdef CONFIG_CPU_BPREDICT_DISABLE
80	bic	r0, r0, #CR_Z
81#endif
82#ifdef CONFIG_CPU_ICACHE_DISABLE
83	bic	r0, r0, #CR_I
84#endif
85#ifdef CONFIG_CPU_HIGH_VECTOR
86	orr	r0, r0, #CR_V
87#else
88	bic	r0, r0, #CR_V
89#endif
90	mcr	p15, 0, r0, c1, c0, 0		@ write control reg
91#endif /* CONFIG_CPU_CP15 */
92
93	b	__mmap_switched			@ clear the BSS and jump
94						@ to start_kernel
95ENDPROC(__after_proc_init)
96	.ltorg
97
98#include "head-common.S"
99