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/thread_info.h> 21#include <asm/system.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 __HEAD 36ENTRY(stext) 37 setmode PSR_F_BIT | PSR_I_BIT | SVC_MODE, r9 @ ensure svc mode 38 @ and irqs disabled 39#ifndef CONFIG_CPU_CP15 40 ldr r9, =CONFIG_PROCESSOR_ID 41#else 42 mrc p15, 0, r9, c0, c0 @ get processor id 43#endif 44 bl __lookup_processor_type @ r5=procinfo r9=cpuid 45 movs r10, r5 @ invalid processor (r5=0)? 46 beq __error_p @ yes, error 'p' 47 bl __lookup_machine_type @ r5=machinfo 48 movs r8, r5 @ invalid machine (r5=0)? 49 beq __error_a @ yes, error 'a' 50 51 adr lr, BSYM(__after_proc_init) @ return (PIC) address 52 ARM( add pc, r10, #PROCINFO_INITFUNC ) 53 THUMB( add r12, r10, #PROCINFO_INITFUNC ) 54 THUMB( mov pc, r12 ) 55ENDPROC(stext) 56 57/* 58 * Set the Control Register and Read the process ID. 59 */ 60__after_proc_init: 61#ifdef CONFIG_CPU_CP15 62 /* 63 * CP15 system control register value returned in r0 from 64 * the CPU init function. 65 */ 66#ifdef CONFIG_ALIGNMENT_TRAP 67 orr r0, r0, #CR_A 68#else 69 bic r0, r0, #CR_A 70#endif 71#ifdef CONFIG_CPU_DCACHE_DISABLE 72 bic r0, r0, #CR_C 73#endif 74#ifdef CONFIG_CPU_BPREDICT_DISABLE 75 bic r0, r0, #CR_Z 76#endif 77#ifdef CONFIG_CPU_ICACHE_DISABLE 78 bic r0, r0, #CR_I 79#endif 80#ifdef CONFIG_CPU_HIGH_VECTOR 81 orr r0, r0, #CR_V 82#else 83 bic r0, r0, #CR_V 84#endif 85 mcr p15, 0, r0, c1, c0, 0 @ write control reg 86#endif /* CONFIG_CPU_CP15 */ 87 88 b __mmap_switched @ clear the BSS and jump 89 @ to start_kernel 90ENDPROC(__after_proc_init) 91 .ltorg 92 93#include "head-common.S" 94