Hyok S. Choi | 75d9083 | 2006-03-27 14:58:25 +0100 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/arm/kernel/head-common.S |
| 3 | * |
| 4 | * Copyright (C) 1994-2002 Russell King |
| 5 | * Copyright (c) 2003 ARM Limited |
| 6 | * All Rights Reserved |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 as |
| 10 | * published by the Free Software Foundation. |
| 11 | * |
| 12 | */ |
| 13 | |
| 14 | .type __switch_data, %object |
| 15 | __switch_data: |
| 16 | .long __mmap_switched |
| 17 | .long __data_loc @ r4 |
| 18 | .long __data_start @ r5 |
| 19 | .long __bss_start @ r6 |
| 20 | .long _end @ r7 |
| 21 | .long processor_id @ r4 |
| 22 | .long __machine_arch_type @ r5 |
| 23 | .long cr_alignment @ r6 |
| 24 | .long init_thread_union + THREAD_START_SP @ sp |
| 25 | |
| 26 | /* |
| 27 | * The following fragment of code is executed with the MMU on in MMU mode, |
| 28 | * and uses absolute addresses; this is not position independent. |
| 29 | * |
| 30 | * r0 = cp#15 control register |
| 31 | * r1 = machine ID |
| 32 | * r9 = processor ID |
| 33 | */ |
| 34 | .type __mmap_switched, %function |
| 35 | __mmap_switched: |
| 36 | adr r3, __switch_data + 4 |
| 37 | |
| 38 | ldmia r3!, {r4, r5, r6, r7} |
| 39 | cmp r4, r5 @ Copy data segment if needed |
| 40 | 1: cmpne r5, r6 |
| 41 | ldrne fp, [r4], #4 |
| 42 | strne fp, [r5], #4 |
| 43 | bne 1b |
| 44 | |
| 45 | mov fp, #0 @ Clear BSS (and zero fp) |
| 46 | 1: cmp r6, r7 |
| 47 | strcc fp, [r6],#4 |
| 48 | bcc 1b |
| 49 | |
| 50 | ldmia r3, {r4, r5, r6, sp} |
| 51 | str r9, [r4] @ Save processor ID |
| 52 | str r1, [r5] @ Save machine type |
| 53 | bic r4, r0, #CR_A @ Clear 'A' bit |
| 54 | stmia r6, {r0, r4} @ Save control register values |
| 55 | b start_kernel |
| 56 | |
| 57 | /* |
| 58 | * Exception handling. Something went wrong and we can't proceed. We |
| 59 | * ought to tell the user, but since we don't have any guarantee that |
| 60 | * we're even running on the right architecture, we do virtually nothing. |
| 61 | * |
| 62 | * If CONFIG_DEBUG_LL is set we try to print out something about the error |
| 63 | * and hope for the best (useful if bootloader fails to pass a proper |
| 64 | * machine ID for example). |
| 65 | */ |
| 66 | |
| 67 | .type __error_p, %function |
| 68 | __error_p: |
| 69 | #ifdef CONFIG_DEBUG_LL |
| 70 | adr r0, str_p1 |
| 71 | bl printascii |
| 72 | b __error |
| 73 | str_p1: .asciz "\nError: unrecognized/unsupported processor variant.\n" |
| 74 | .align |
| 75 | #endif |
| 76 | |
| 77 | .type __error_a, %function |
| 78 | __error_a: |
| 79 | #ifdef CONFIG_DEBUG_LL |
| 80 | mov r4, r1 @ preserve machine ID |
| 81 | adr r0, str_a1 |
| 82 | bl printascii |
| 83 | mov r0, r4 |
| 84 | bl printhex8 |
| 85 | adr r0, str_a2 |
| 86 | bl printascii |
| 87 | adr r3, 3f |
| 88 | ldmia r3, {r4, r5, r6} @ get machine desc list |
| 89 | sub r4, r3, r4 @ get offset between virt&phys |
| 90 | add r5, r5, r4 @ convert virt addresses to |
| 91 | add r6, r6, r4 @ physical address space |
| 92 | 1: ldr r0, [r5, #MACHINFO_TYPE] @ get machine type |
| 93 | bl printhex8 |
| 94 | mov r0, #'\t' |
| 95 | bl printch |
| 96 | ldr r0, [r5, #MACHINFO_NAME] @ get machine name |
| 97 | add r0, r0, r4 |
| 98 | bl printascii |
| 99 | mov r0, #'\n' |
| 100 | bl printch |
| 101 | add r5, r5, #SIZEOF_MACHINE_DESC @ next machine_desc |
| 102 | cmp r5, r6 |
| 103 | blo 1b |
| 104 | adr r0, str_a3 |
| 105 | bl printascii |
| 106 | b __error |
| 107 | str_a1: .asciz "\nError: unrecognized/unsupported machine ID (r1 = 0x" |
| 108 | str_a2: .asciz ").\n\nAvailable machine support:\n\nID (hex)\tNAME\n" |
| 109 | str_a3: .asciz "\nPlease check your kernel config and/or bootloader.\n" |
| 110 | .align |
| 111 | #endif |
| 112 | |
| 113 | .type __error, %function |
| 114 | __error: |
| 115 | #ifdef CONFIG_ARCH_RPC |
| 116 | /* |
| 117 | * Turn the screen red on a error - RiscPC only. |
| 118 | */ |
| 119 | mov r0, #0x02000000 |
| 120 | mov r3, #0x11 |
| 121 | orr r3, r3, r3, lsl #8 |
| 122 | orr r3, r3, r3, lsl #16 |
| 123 | str r3, [r0], #4 |
| 124 | str r3, [r0], #4 |
| 125 | str r3, [r0], #4 |
| 126 | str r3, [r0], #4 |
| 127 | #endif |
| 128 | 1: mov r0, r0 |
| 129 | b 1b |
| 130 | |
| 131 | |
| 132 | /* |
| 133 | * Read processor ID register (CP#15, CR0), and look up in the linker-built |
| 134 | * supported processor list. Note that we can't use the absolute addresses |
| 135 | * for the __proc_info lists since we aren't running with the MMU on |
| 136 | * (and therefore, we are not in the correct address space). We have to |
| 137 | * calculate the offset. |
| 138 | * |
| 139 | * r9 = cpuid |
| 140 | * Returns: |
| 141 | * r3, r4, r6 corrupted |
| 142 | * r5 = proc_info pointer in physical address space |
| 143 | * r9 = cpuid (preserved) |
| 144 | */ |
| 145 | .type __lookup_processor_type, %function |
| 146 | __lookup_processor_type: |
| 147 | adr r3, 3f |
| 148 | ldmda r3, {r5 - r7} |
| 149 | sub r3, r3, r7 @ get offset between virt&phys |
| 150 | add r5, r5, r3 @ convert virt addresses to |
| 151 | add r6, r6, r3 @ physical address space |
| 152 | 1: ldmia r5, {r3, r4} @ value, mask |
| 153 | and r4, r4, r9 @ mask wanted bits |
| 154 | teq r3, r4 |
| 155 | beq 2f |
| 156 | add r5, r5, #PROC_INFO_SZ @ sizeof(proc_info_list) |
| 157 | cmp r5, r6 |
| 158 | blo 1b |
| 159 | mov r5, #0 @ unknown processor |
| 160 | 2: mov pc, lr |
| 161 | |
| 162 | /* |
| 163 | * This provides a C-API version of the above function. |
| 164 | */ |
| 165 | ENTRY(lookup_processor_type) |
| 166 | stmfd sp!, {r4 - r7, r9, lr} |
| 167 | mov r9, r0 |
| 168 | bl __lookup_processor_type |
| 169 | mov r0, r5 |
| 170 | ldmfd sp!, {r4 - r7, r9, pc} |
| 171 | |
| 172 | /* |
| 173 | * Look in include/asm-arm/procinfo.h and arch/arm/kernel/arch.[ch] for |
| 174 | * more information about the __proc_info and __arch_info structures. |
| 175 | */ |
| 176 | .long __proc_info_begin |
| 177 | .long __proc_info_end |
| 178 | 3: .long . |
| 179 | .long __arch_info_begin |
| 180 | .long __arch_info_end |
| 181 | |
| 182 | /* |
| 183 | * Lookup machine architecture in the linker-build list of architectures. |
| 184 | * Note that we can't use the absolute addresses for the __arch_info |
| 185 | * lists since we aren't running with the MMU on (and therefore, we are |
| 186 | * not in the correct address space). We have to calculate the offset. |
| 187 | * |
| 188 | * r1 = machine architecture number |
| 189 | * Returns: |
| 190 | * r3, r4, r6 corrupted |
| 191 | * r5 = mach_info pointer in physical address space |
| 192 | */ |
| 193 | .type __lookup_machine_type, %function |
| 194 | __lookup_machine_type: |
| 195 | adr r3, 3b |
| 196 | ldmia r3, {r4, r5, r6} |
| 197 | sub r3, r3, r4 @ get offset between virt&phys |
| 198 | add r5, r5, r3 @ convert virt addresses to |
| 199 | add r6, r6, r3 @ physical address space |
| 200 | 1: ldr r3, [r5, #MACHINFO_TYPE] @ get machine type |
| 201 | teq r3, r1 @ matches loader number? |
| 202 | beq 2f @ found |
| 203 | add r5, r5, #SIZEOF_MACHINE_DESC @ next machine_desc |
| 204 | cmp r5, r6 |
| 205 | blo 1b |
| 206 | mov r5, #0 @ unknown machine |
| 207 | 2: mov pc, lr |
| 208 | |
| 209 | /* |
| 210 | * This provides a C-API version of the above function. |
| 211 | */ |
| 212 | ENTRY(lookup_machine_type) |
| 213 | stmfd sp!, {r4 - r6, lr} |
| 214 | mov r1, r0 |
| 215 | bl __lookup_machine_type |
| 216 | mov r0, r5 |
| 217 | ldmfd sp!, {r4 - r6, pc} |