ARM: Add base support for ARMv7-M
[deliverable/linux.git] / arch / arm / kernel / head-nommu.S
CommitLineData
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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)
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12 *
13 */
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14#include <linux/linkage.h>
15#include <linux/init.h>
16
17#include <asm/assembler.h>
75d90832 18#include <asm/ptrace.h>
2eb9d315 19#include <asm/asm-offsets.h>
15d07dc9 20#include <asm/cp15.h>
3b920cef 21#include <asm/thread_info.h>
55bdd694 22#include <asm/v7m.h>
75d90832 23
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24/*
25 * Kernel startup entry point.
26 * ---------------------------
27 *
28 * This is normally called from the decompressor code. The requirements
29 * are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
30 * r1 = machine nr.
31 *
32 * See linux/arch/arm/tools/mach-types for the complete list of machine
33 * numbers for r1.
34 *
35 */
540b5738 36
2abc1c50 37 __HEAD
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38
39#ifdef CONFIG_CPU_THUMBONLY
40 .thumb
41ENTRY(stext)
42#else
43 .arm
75d90832 44ENTRY(stext)
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45
46 THUMB( adr r9, BSYM(1f) ) @ Kernel is always entered in ARM.
47 THUMB( bx r9 ) @ If this is a Thumb-2 kernel,
48 THUMB( .thumb ) @ switch to Thumb now.
49 THUMB(1: )
bc7dea00 50#endif
540b5738 51
b86040a5 52 setmode PSR_F_BIT | PSR_I_BIT | SVC_MODE, r9 @ ensure svc mode
75d90832 53 @ and irqs disabled
55bdd694 54#if defined(CONFIG_CPU_CP15)
75d90832 55 mrc p15, 0, r9, c0, c0 @ get processor id
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56#elif defined(CONFIG_CPU_V7M)
57 ldr r9, =BASEADDR_V7M_SCB
58 ldr r9, [r9, V7M_SCB_CPUID]
59#else
60 ldr r9, =CONFIG_PROCESSOR_ID
f12d0d7c 61#endif
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62 bl __lookup_processor_type @ r5=procinfo r9=cpuid
63 movs r10, r5 @ invalid processor (r5=0)?
64 beq __error_p @ yes, error 'p'
75d90832 65
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66 adr lr, BSYM(__after_proc_init) @ return (PIC) address
67 ARM( add pc, r10, #PROCINFO_INITFUNC )
68 THUMB( add r12, r10, #PROCINFO_INITFUNC )
69 THUMB( mov pc, r12 )
93ed3970 70ENDPROC(stext)
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71
72/*
73 * Set the Control Register and Read the process ID.
74 */
75d90832 75__after_proc_init:
f12d0d7c 76#ifdef CONFIG_CPU_CP15
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77 /*
78 * CP15 system control register value returned in r0 from
79 * the CPU init function.
80 */
76e09204 81#if defined(CONFIG_ALIGNMENT_TRAP) && __LINUX_ARM_ARCH__ < 6
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82 orr r0, r0, #CR_A
83#else
84 bic r0, r0, #CR_A
85#endif
86#ifdef CONFIG_CPU_DCACHE_DISABLE
87 bic r0, r0, #CR_C
88#endif
89#ifdef CONFIG_CPU_BPREDICT_DISABLE
90 bic r0, r0, #CR_Z
91#endif
92#ifdef CONFIG_CPU_ICACHE_DISABLE
93 bic r0, r0, #CR_I
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94#endif
95#ifdef CONFIG_CPU_HIGH_VECTOR
96 orr r0, r0, #CR_V
97#else
98 bic r0, r0, #CR_V
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99#endif
100 mcr p15, 0, r0, c1, c0, 0 @ write control reg
f12d0d7c 101#endif /* CONFIG_CPU_CP15 */
75d90832 102
f131a080 103 b __mmap_switched @ clear the BSS and jump
75d90832 104 @ to start_kernel
93ed3970 105ENDPROC(__after_proc_init)
3b920cef 106 .ltorg
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107
108#include "head-common.S"
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