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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 | /* * linux/arch/arm/kernel/head-common.S * * Copyright (C) 1994-2002 Russell King * Copyright (c) 2003 ARM Limited * All Rights Reserved * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * */ #include <asm/assembler.h> #define ATAG_CORE 0x54410001 #define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2) #define ATAG_CORE_SIZE_EMPTY ((2*4) >> 2) #ifdef CONFIG_CPU_BIG_ENDIAN #define OF_DT_MAGIC 0xd00dfeed #else #define OF_DT_MAGIC 0xedfe0dd0 /* 0xd00dfeed in big-endian */ #endif /* * Exception handling. Something went wrong and we can't proceed. We * ought to tell the user, but since we don't have any guarantee that * we're even running on the right architecture, we do virtually nothing. * * If CONFIG_DEBUG_LL is set we try to print out something about the error * and hope for the best (useful if bootloader fails to pass a proper * machine ID for example). */ __HEAD /* Determine validity of the r2 atags pointer. The heuristic requires * that the pointer be aligned, in the first 16k of physical RAM and * that the ATAG_CORE marker is first and present. If CONFIG_OF_FLATTREE * is selected, then it will also accept a dtb pointer. Future revisions * of this function may be more lenient with the physical address and * may also be able to move the ATAGS block if necessary. * * Returns: * r2 either valid atags pointer, valid dtb pointer, or zero * r5, r6 corrupted */ __vet_atags: tst r2, #0x3 @ aligned? bne 1f ldr r5, [r2, #0] #ifdef CONFIG_OF_FLATTREE ldr r6, =OF_DT_MAGIC @ is it a DTB? cmp r5, r6 beq 2f #endif cmp r5, #ATAG_CORE_SIZE @ is first tag ATAG_CORE? cmpne r5, #ATAG_CORE_SIZE_EMPTY bne 1f ldr r5, [r2, #4] ldr r6, =ATAG_CORE cmp r5, r6 bne 1f 2: ret lr @ atag/dtb pointer is ok 1: mov r2, #0 ret lr ENDPROC(__vet_atags) /* * The following fragment of code is executed with the MMU on in MMU mode, * and uses absolute addresses; this is not position independent. * * r0 = cp#15 control register * r1 = machine ID * r2 = atags/dtb pointer * r9 = processor ID */ __INIT __mmap_switched: adr r3, __mmap_switched_data ldmia r3!, {r4, r5, r6, r7} cmp r4, r5 @ Copy data segment if needed 1: cmpne r5, r6 ldrne fp, [r4], #4 strne fp, [r5], #4 bne 1b mov fp, #0 @ Clear BSS (and zero fp) 1: cmp r6, r7 strcc fp, [r6],#4 bcc 1b ARM( ldmia r3, {r4, r5, r6, r7, sp}) THUMB( ldmia r3, {r4, r5, r6, r7} ) THUMB( ldr sp, [r3, #16] ) str r9, [r4] @ Save processor ID str r1, [r5] @ Save machine type str r2, [r6] @ Save atags pointer cmp r7, #0 strne r0, [r7] @ Save control register values b start_kernel ENDPROC(__mmap_switched) .align 2 .type __mmap_switched_data, %object __mmap_switched_data: .long __data_loc @ r4 .long _sdata @ r5 .long __bss_start @ r6 .long _end @ r7 .long processor_id @ r4 .long __machine_arch_type @ r5 .long __atags_pointer @ r6 #ifdef CONFIG_CPU_CP15 .long cr_alignment @ r7 #else .long 0 @ r7 #endif .long init_thread_union + THREAD_START_SP @ sp .size __mmap_switched_data, . - __mmap_switched_data /* * This provides a C-API version of __lookup_processor_type */ ENTRY(lookup_processor_type) stmfd sp!, {r4 - r6, r9, lr} mov r9, r0 bl __lookup_processor_type mov r0, r5 ldmfd sp!, {r4 - r6, r9, pc} ENDPROC(lookup_processor_type) __FINIT .text /* * Read processor ID register (CP#15, CR0), and look up in the linker-built * supported processor list. Note that we can't use the absolute addresses * for the __proc_info lists since we aren't running with the MMU on * (and therefore, we are not in the correct address space). We have to * calculate the offset. * * r9 = cpuid * Returns: * r3, r4, r6 corrupted * r5 = proc_info pointer in physical address space * r9 = cpuid (preserved) */ __lookup_processor_type: adr r3, __lookup_processor_type_data ldmia r3, {r4 - r6} sub r3, r3, r4 @ get offset between virt&phys add r5, r5, r3 @ convert virt addresses to add r6, r6, r3 @ physical address space 1: ldmia r5, {r3, r4} @ value, mask and r4, r4, r9 @ mask wanted bits teq r3, r4 beq 2f add r5, r5, #PROC_INFO_SZ @ sizeof(proc_info_list) cmp r5, r6 blo 1b mov r5, #0 @ unknown processor 2: ret lr ENDPROC(__lookup_processor_type) /* * Look in <asm/procinfo.h> for information about the __proc_info structure. */ .align 2 .type __lookup_processor_type_data, %object __lookup_processor_type_data: .long . .long __proc_info_begin .long __proc_info_end .size __lookup_processor_type_data, . - __lookup_processor_type_data __error_lpae: #ifdef CONFIG_DEBUG_LL adr r0, str_lpae bl printascii b __error str_lpae: .asciz "\nError: Kernel with LPAE support, but CPU does not support LPAE.\n" #else b __error #endif .align ENDPROC(__error_lpae) __error_p: #ifdef CONFIG_DEBUG_LL adr r0, str_p1 bl printascii mov r0, r9 bl printhex8 adr r0, str_p2 bl printascii b __error str_p1: .asciz "\nError: unrecognized/unsupported processor variant (0x" str_p2: .asciz ").\n" .align #endif ENDPROC(__error_p) __error: #ifdef CONFIG_ARCH_RPC /* * Turn the screen red on a error - RiscPC only. */ mov r0, #0x02000000 mov r3, #0x11 orr r3, r3, r3, lsl #8 orr r3, r3, r3, lsl #16 str r3, [r0], #4 str r3, [r0], #4 str r3, [r0], #4 str r3, [r0], #4 #endif 1: mov r0, r0 b 1b ENDPROC(__error) |