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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)
12 * for 32-bit CPUs which has a process ID register(CP15).
13 *
14 */
15#include <linux/config.h>
16#include <linux/linkage.h>
17#include <linux/init.h>
18
19#include <asm/assembler.h>
20#include <asm/mach-types.h>
21#include <asm/procinfo.h>
22#include <asm/ptrace.h>
23#include <asm/constants.h>
24#include <asm/system.h>
25
26#define PROCINFO_INITFUNC 12
27
28/*
29 * Kernel startup entry point.
30 * ---------------------------
31 *
32 * This is normally called from the decompressor code. The requirements
33 * are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
34 * r1 = machine nr.
35 *
36 * See linux/arch/arm/tools/mach-types for the complete list of machine
37 * numbers for r1.
38 *
39 */
40 __INIT
41 .type stext, %function
42ENTRY(stext)
43 msr cpsr_c, #PSR_F_BIT | PSR_I_BIT | MODE_SVC @ ensure svc mode
44 @ and irqs disabled
45 mrc p15, 0, r9, c0, c0 @ get processor id
46 bl __lookup_processor_type @ r5=procinfo r9=cpuid
47 movs r10, r5 @ invalid processor (r5=0)?
48 beq __error_p @ yes, error 'p'
49 bl __lookup_machine_type @ r5=machinfo
50 movs r8, r5 @ invalid machine (r5=0)?
51 beq __error_a @ yes, error 'a'
52
53 ldr r13, __switch_data @ address to jump to after
54 @ the initialization is done
55 adr lr, __after_proc_init @ return (PIC) address
56 add pc, r10, #PROCINFO_INITFUNC
57
58/*
59 * Set the Control Register and Read the process ID.
60 */
61 .type __after_proc_init, %function
62__after_proc_init:
63 mrc p15, 0, r0, c1, c0, 0 @ read control reg
64#ifdef CONFIG_ALIGNMENT_TRAP
65 orr r0, r0, #CR_A
66#else
67 bic r0, r0, #CR_A
68#endif
69#ifdef CONFIG_CPU_DCACHE_DISABLE
70 bic r0, r0, #CR_C
71#endif
72#ifdef CONFIG_CPU_BPREDICT_DISABLE
73 bic r0, r0, #CR_Z
74#endif
75#ifdef CONFIG_CPU_ICACHE_DISABLE
76 bic r0, r0, #CR_I
77#endif
78 mcr p15, 0, r0, c1, c0, 0 @ write control reg
79
80 mov pc, r13 @ clear the BSS and jump
81 @ to start_kernel
82
83#include "head-common.S"