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