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 | */ |
Russell King | 6ebbf2c | 2014-06-30 16:29:12 +0100 | [diff] [blame] | 13 | #include <asm/assembler.h> |
Hyok S. Choi | 75d9083 | 2006-03-27 14:58:25 +0100 | [diff] [blame] | 14 | |
Greg Ungerer | 9c4c9f3 | 2008-03-05 06:50:07 +0100 | [diff] [blame] | 15 | #define ATAG_CORE 0x54410001 |
| 16 | #define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2) |
David Brown | 31abdb74 | 2009-10-01 17:43:29 +0100 | [diff] [blame] | 17 | #define ATAG_CORE_SIZE_EMPTY ((2*4) >> 2) |
Greg Ungerer | 9c4c9f3 | 2008-03-05 06:50:07 +0100 | [diff] [blame] | 18 | |
Grant Likely | 4c2896e | 2011-04-28 14:27:20 -0600 | [diff] [blame] | 19 | #ifdef CONFIG_CPU_BIG_ENDIAN |
| 20 | #define OF_DT_MAGIC 0xd00dfeed |
| 21 | #else |
| 22 | #define OF_DT_MAGIC 0xedfe0dd0 /* 0xd00dfeed in big-endian */ |
| 23 | #endif |
| 24 | |
Hyok S. Choi | 75d9083 | 2006-03-27 14:58:25 +0100 | [diff] [blame] | 25 | /* |
| 26 | * Exception handling. Something went wrong and we can't proceed. We |
| 27 | * ought to tell the user, but since we don't have any guarantee that |
| 28 | * we're even running on the right architecture, we do virtually nothing. |
| 29 | * |
| 30 | * If CONFIG_DEBUG_LL is set we try to print out something about the error |
| 31 | * and hope for the best (useful if bootloader fails to pass a proper |
| 32 | * machine ID for example). |
| 33 | */ |
Russell King | 80924ac | 2010-10-04 17:45:25 +0100 | [diff] [blame] | 34 | __HEAD |
Bill Gatliff | 9d20fdd | 2007-05-31 22:02:22 +0100 | [diff] [blame] | 35 | |
| 36 | /* Determine validity of the r2 atags pointer. The heuristic requires |
| 37 | * that the pointer be aligned, in the first 16k of physical RAM and |
Grant Likely | 4c2896e | 2011-04-28 14:27:20 -0600 | [diff] [blame] | 38 | * that the ATAG_CORE marker is first and present. If CONFIG_OF_FLATTREE |
| 39 | * is selected, then it will also accept a dtb pointer. Future revisions |
Bill Gatliff | 9d20fdd | 2007-05-31 22:02:22 +0100 | [diff] [blame] | 40 | * of this function may be more lenient with the physical address and |
| 41 | * may also be able to move the ATAGS block if necessary. |
| 42 | * |
Bill Gatliff | 9d20fdd | 2007-05-31 22:02:22 +0100 | [diff] [blame] | 43 | * Returns: |
Grant Likely | 4c2896e | 2011-04-28 14:27:20 -0600 | [diff] [blame] | 44 | * r2 either valid atags pointer, valid dtb pointer, or zero |
Bill Gatliff | 9d20fdd | 2007-05-31 22:02:22 +0100 | [diff] [blame] | 45 | * r5, r6 corrupted |
| 46 | */ |
Bill Gatliff | 9d20fdd | 2007-05-31 22:02:22 +0100 | [diff] [blame] | 47 | __vet_atags: |
| 48 | tst r2, #0x3 @ aligned? |
| 49 | bne 1f |
| 50 | |
Grant Likely | 4c2896e | 2011-04-28 14:27:20 -0600 | [diff] [blame] | 51 | ldr r5, [r2, #0] |
| 52 | #ifdef CONFIG_OF_FLATTREE |
| 53 | ldr r6, =OF_DT_MAGIC @ is it a DTB? |
| 54 | cmp r5, r6 |
| 55 | beq 2f |
| 56 | #endif |
| 57 | cmp r5, #ATAG_CORE_SIZE @ is first tag ATAG_CORE? |
David Brown | 31abdb74 | 2009-10-01 17:43:29 +0100 | [diff] [blame] | 58 | cmpne r5, #ATAG_CORE_SIZE_EMPTY |
Bill Gatliff | 9d20fdd | 2007-05-31 22:02:22 +0100 | [diff] [blame] | 59 | bne 1f |
| 60 | ldr r5, [r2, #4] |
| 61 | ldr r6, =ATAG_CORE |
| 62 | cmp r5, r6 |
| 63 | bne 1f |
| 64 | |
Russell King | 6ebbf2c | 2014-06-30 16:29:12 +0100 | [diff] [blame] | 65 | 2: ret lr @ atag/dtb pointer is ok |
Bill Gatliff | 9d20fdd | 2007-05-31 22:02:22 +0100 | [diff] [blame] | 66 | |
| 67 | 1: mov r2, #0 |
Russell King | 6ebbf2c | 2014-06-30 16:29:12 +0100 | [diff] [blame] | 68 | ret lr |
Catalin Marinas | 93ed397 | 2008-08-28 11:22:32 +0100 | [diff] [blame] | 69 | ENDPROC(__vet_atags) |
Russell King | 5085f3f | 2010-10-01 15:37:05 +0100 | [diff] [blame] | 70 | |
| 71 | /* |
Russell King | 17bb5e2 | 2010-10-04 16:29:35 +0100 | [diff] [blame] | 72 | * The following fragment of code is executed with the MMU on in MMU mode, |
| 73 | * and uses absolute addresses; this is not position independent. |
| 74 | * |
| 75 | * r0 = cp#15 control register |
| 76 | * r1 = machine ID |
Grant Likely | 4c2896e | 2011-04-28 14:27:20 -0600 | [diff] [blame] | 77 | * r2 = atags/dtb pointer |
Russell King | 17bb5e2 | 2010-10-04 16:29:35 +0100 | [diff] [blame] | 78 | * r9 = processor ID |
| 79 | */ |
| 80 | __INIT |
| 81 | __mmap_switched: |
| 82 | adr r3, __mmap_switched_data |
| 83 | |
| 84 | ldmia r3!, {r4, r5, r6, r7} |
| 85 | cmp r4, r5 @ Copy data segment if needed |
| 86 | 1: cmpne r5, r6 |
| 87 | ldrne fp, [r4], #4 |
| 88 | strne fp, [r5], #4 |
| 89 | bne 1b |
| 90 | |
| 91 | mov fp, #0 @ Clear BSS (and zero fp) |
| 92 | 1: cmp r6, r7 |
| 93 | strcc fp, [r6],#4 |
| 94 | bcc 1b |
| 95 | |
| 96 | ARM( ldmia r3, {r4, r5, r6, r7, sp}) |
| 97 | THUMB( ldmia r3, {r4, r5, r6, r7} ) |
| 98 | THUMB( ldr sp, [r3, #16] ) |
| 99 | str r9, [r4] @ Save processor ID |
| 100 | str r1, [r5] @ Save machine type |
| 101 | str r2, [r6] @ Save atags pointer |
Uwe Kleine-König | b849a60 | 2012-01-16 10:34:31 +0100 | [diff] [blame] | 102 | cmp r7, #0 |
Russell King | 0aeb340 | 2014-04-13 19:43:26 +0100 | [diff] [blame] | 103 | strne r0, [r7] @ Save control register values |
Russell King | 17bb5e2 | 2010-10-04 16:29:35 +0100 | [diff] [blame] | 104 | b start_kernel |
| 105 | ENDPROC(__mmap_switched) |
| 106 | |
| 107 | .align 2 |
| 108 | .type __mmap_switched_data, %object |
| 109 | __mmap_switched_data: |
| 110 | .long __data_loc @ r4 |
Russell King | a0a5568 | 2010-10-18 22:34:47 +0100 | [diff] [blame] | 111 | .long _sdata @ r5 |
Russell King | 17bb5e2 | 2010-10-04 16:29:35 +0100 | [diff] [blame] | 112 | .long __bss_start @ r6 |
| 113 | .long _end @ r7 |
| 114 | .long processor_id @ r4 |
| 115 | .long __machine_arch_type @ r5 |
| 116 | .long __atags_pointer @ r6 |
Uwe Kleine-König | b849a60 | 2012-01-16 10:34:31 +0100 | [diff] [blame] | 117 | #ifdef CONFIG_CPU_CP15 |
Russell King | 17bb5e2 | 2010-10-04 16:29:35 +0100 | [diff] [blame] | 118 | .long cr_alignment @ r7 |
Uwe Kleine-König | b849a60 | 2012-01-16 10:34:31 +0100 | [diff] [blame] | 119 | #else |
| 120 | .long 0 @ r7 |
| 121 | #endif |
Russell King | 17bb5e2 | 2010-10-04 16:29:35 +0100 | [diff] [blame] | 122 | .long init_thread_union + THREAD_START_SP @ sp |
| 123 | .size __mmap_switched_data, . - __mmap_switched_data |
| 124 | |
Russell King | 8d13b44 | 2019-02-14 09:49:24 -0500 | [diff] [blame] | 125 | __FINIT |
| 126 | .text |
| 127 | |
Russell King | 17bb5e2 | 2010-10-04 16:29:35 +0100 | [diff] [blame] | 128 | /* |
Russell King | 17bb5e2 | 2010-10-04 16:29:35 +0100 | [diff] [blame] | 129 | * This provides a C-API version of __lookup_processor_type |
| 130 | */ |
| 131 | ENTRY(lookup_processor_type) |
| 132 | stmfd sp!, {r4 - r6, r9, lr} |
| 133 | mov r9, r0 |
| 134 | bl __lookup_processor_type |
| 135 | mov r0, r5 |
| 136 | ldmfd sp!, {r4 - r6, r9, pc} |
| 137 | ENDPROC(lookup_processor_type) |
| 138 | |
| 139 | /* |
Russell King | 5085f3f | 2010-10-01 15:37:05 +0100 | [diff] [blame] | 140 | * Read processor ID register (CP#15, CR0), and look up in the linker-built |
| 141 | * supported processor list. Note that we can't use the absolute addresses |
| 142 | * for the __proc_info lists since we aren't running with the MMU on |
| 143 | * (and therefore, we are not in the correct address space). We have to |
| 144 | * calculate the offset. |
| 145 | * |
| 146 | * r9 = cpuid |
| 147 | * Returns: |
| 148 | * r3, r4, r6 corrupted |
| 149 | * r5 = proc_info pointer in physical address space |
| 150 | * r9 = cpuid (preserved) |
| 151 | */ |
Russell King | 5085f3f | 2010-10-01 15:37:05 +0100 | [diff] [blame] | 152 | __lookup_processor_type: |
| 153 | adr r3, __lookup_processor_type_data |
| 154 | ldmia r3, {r4 - r6} |
| 155 | sub r3, r3, r4 @ get offset between virt&phys |
| 156 | add r5, r5, r3 @ convert virt addresses to |
| 157 | add r6, r6, r3 @ physical address space |
| 158 | 1: ldmia r5, {r3, r4} @ value, mask |
| 159 | and r4, r4, r9 @ mask wanted bits |
| 160 | teq r3, r4 |
| 161 | beq 2f |
| 162 | add r5, r5, #PROC_INFO_SZ @ sizeof(proc_info_list) |
| 163 | cmp r5, r6 |
| 164 | blo 1b |
| 165 | mov r5, #0 @ unknown processor |
Russell King | 6ebbf2c | 2014-06-30 16:29:12 +0100 | [diff] [blame] | 166 | 2: ret lr |
Russell King | 5085f3f | 2010-10-01 15:37:05 +0100 | [diff] [blame] | 167 | ENDPROC(__lookup_processor_type) |
| 168 | |
| 169 | /* |
| 170 | * Look in <asm/procinfo.h> for information about the __proc_info structure. |
| 171 | */ |
| 172 | .align 2 |
| 173 | .type __lookup_processor_type_data, %object |
| 174 | __lookup_processor_type_data: |
| 175 | .long . |
| 176 | .long __proc_info_begin |
| 177 | .long __proc_info_end |
| 178 | .size __lookup_processor_type_data, . - __lookup_processor_type_data |
Russell King | c083c66 | 2010-10-04 17:39:20 +0100 | [diff] [blame] | 179 | |
Thomas Petazzoni | b363457 | 2014-02-18 17:02:54 +0100 | [diff] [blame] | 180 | __error_lpae: |
| 181 | #ifdef CONFIG_DEBUG_LL |
| 182 | adr r0, str_lpae |
| 183 | bl printascii |
| 184 | b __error |
| 185 | str_lpae: .asciz "\nError: Kernel with LPAE support, but CPU does not support LPAE.\n" |
| 186 | #else |
| 187 | b __error |
| 188 | #endif |
| 189 | .align |
| 190 | ENDPROC(__error_lpae) |
| 191 | |
Russell King | c083c66 | 2010-10-04 17:39:20 +0100 | [diff] [blame] | 192 | __error_p: |
| 193 | #ifdef CONFIG_DEBUG_LL |
| 194 | adr r0, str_p1 |
| 195 | bl printascii |
| 196 | mov r0, r9 |
| 197 | bl printhex8 |
| 198 | adr r0, str_p2 |
| 199 | bl printascii |
| 200 | b __error |
| 201 | str_p1: .asciz "\nError: unrecognized/unsupported processor variant (0x" |
| 202 | str_p2: .asciz ").\n" |
| 203 | .align |
| 204 | #endif |
| 205 | ENDPROC(__error_p) |
| 206 | |
| 207 | __error: |
| 208 | #ifdef CONFIG_ARCH_RPC |
| 209 | /* |
| 210 | * Turn the screen red on a error - RiscPC only. |
| 211 | */ |
| 212 | mov r0, #0x02000000 |
| 213 | mov r3, #0x11 |
| 214 | orr r3, r3, r3, lsl #8 |
| 215 | orr r3, r3, r3, lsl #16 |
| 216 | str r3, [r0], #4 |
| 217 | str r3, [r0], #4 |
| 218 | str r3, [r0], #4 |
| 219 | str r3, [r0], #4 |
| 220 | #endif |
| 221 | 1: mov r0, r0 |
| 222 | b 1b |
| 223 | ENDPROC(__error) |