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 .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