arch/arm/lib/vectors.S

   1 /*
   2  *  vectors - Generic ARM exception table code
   3  *
   4  *  Copyright (c) 1998  Dan Malek <dmalek@jlc.net>
   5  *  Copyright (c) 1999  Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
   6  *  Copyright (c) 2000  Wolfgang Denk <wd@denx.de>
   7  *  Copyright (c) 2001  Alex Züpke <azu@sysgo.de>
   8  *  Copyright (c) 2001  Marius Gröger <mag@sysgo.de>
   9  *  Copyright (c) 2002  Alex Züpke <azu@sysgo.de>
  10  *  Copyright (c) 2002  Gary Jennejohn <garyj@denx.de>
  11  *  Copyright (c) 2002  Kyle Harris <kharris@nexus-tech.net>
  12  *
  13  * SPDX-License-Identifier:     GPL-2.0+
  14  */
  15
  16 #include <config.h>
  17
  18 /*
  19  *************************************************************************
  20  *
  21  * Symbol _start is referenced elsewhere, so make it global
  22  *
  23  *************************************************************************
  24  */
  25
  26 .globl _start
  27
  28 /*
  29  *************************************************************************
  30  *
  31  * Vectors have their own section so linker script can map them easily
  32  *
  33  *************************************************************************
  34  */
  35
  36         .section ".vectors", "ax"
  37
  38 /*
  39  *************************************************************************
  40  *
  41  * Exception vectors as described in ARM reference manuals
  42  *
  43  * Uses indirect branch to allow reaching handlers anywhere in memory.
  44  *
  45  *************************************************************************
  46  */
  47
  48 _start:
  49
  50 #ifdef CONFIG_SYS_DV_NOR_BOOT_CFG
  51         .word   CONFIG_SYS_DV_NOR_BOOT_CFG
  52 #endif
  53
  54         b       reset
  55         ldr     pc, _undefined_instruction
  56         ldr     pc, _software_interrupt
  57         ldr     pc, _prefetch_abort
  58         ldr     pc, _data_abort
  59         ldr     pc, _not_used
  60         ldr     pc, _irq
  61         ldr     pc, _fiq
  62
  63 #ifdef CONFIG_ENABLE_ARM_SOC_BOOT0_HOOK
  64 /*
  65  * Various SoCs need something special and SoC-specific up front in
  66  * order to boot, allow them to set that in their boot0.h file and then
  67  * use it here.
  68  */
  69 #include <asm/arch/boot0.h>
  70 #endif
  71
  72 /*
  73  *************************************************************************
  74  *
  75  * Indirect vectors table
  76  *
  77  * Symbols referenced here must be defined somewhere else
  78  *
  79  *************************************************************************
  80  */
  81
  82         .globl  _undefined_instruction
  83         .globl  _software_interrupt
  84         .globl  _prefetch_abort
  85         .globl  _data_abort
  86         .globl  _not_used
  87         .globl  _irq
  88         .globl  _fiq
  89
  90 _undefined_instruction: .word undefined_instruction
  91 _software_interrupt:    .word software_interrupt
  92 _prefetch_abort:        .word prefetch_abort
  93 _data_abort:            .word data_abort
  94 _not_used:              .word not_used
  95 _irq:                   .word irq
  96 _fiq:                   .word fiq
  97
  98         .balignl 16,0xdeadbeef
  99
 100 /*
 101  *************************************************************************
 102  *
 103  * Interrupt handling
 104  *
 105  *************************************************************************
 106  */
 107
 108 /* SPL interrupt handling: just hang */
 109
 110 #ifdef CONFIG_SPL_BUILD
 111
 112         .align  5
 113 undefined_instruction:
 114 software_interrupt:
 115 prefetch_abort:
 116 data_abort:
 117 not_used:
 118 irq:
 119 fiq:
 120
 121 1:
 122         bl      1b                      /* hang and never return */
 123
 124 #else   /* !CONFIG_SPL_BUILD */
 125
 126 /* IRQ stack memory (calculated at run-time) + 8 bytes */
 127 .globl IRQ_STACK_START_IN
 128 IRQ_STACK_START_IN:
 129         .word   0x0badc0de
 130
 131 @
 132 @ IRQ stack frame.
 133 @
 134 #define S_FRAME_SIZE    72
 135
 136 #define S_OLD_R0        68
 137 #define S_PSR           64
 138 #define S_PC            60
 139 #define S_LR            56
 140 #define S_SP            52
 141
 142 #define S_IP            48
 143 #define S_FP            44
 144 #define S_R10           40
 145 #define S_R9            36
 146 #define S_R8            32
 147 #define S_R7            28
 148 #define S_R6            24
 149 #define S_R5            20
 150 #define S_R4            16
 151 #define S_R3            12
 152 #define S_R2            8
 153 #define S_R1            4
 154 #define S_R0            0
 155
 156 #define MODE_SVC 0x13
 157 #define I_BIT    0x80
 158
 159 /*
 160  * use bad_save_user_regs for abort/prefetch/undef/swi ...
 161  * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
 162  */
 163
 164         .macro  bad_save_user_regs
 165         @ carve out a frame on current user stack
 166         sub     sp, sp, #S_FRAME_SIZE
 167         stmia   sp, {r0 - r12}  @ Save user registers (now in svc mode) r0-r12
 168         ldr     r2, IRQ_STACK_START_IN
 169         @ get values for "aborted" pc and cpsr (into parm regs)
 170         ldmia   r2, {r2 - r3}
 171         add     r0, sp, #S_FRAME_SIZE           @ grab pointer to old stack
 172         add     r5, sp, #S_SP
 173         mov     r1, lr
 174         stmia   r5, {r0 - r3}   @ save sp_SVC, lr_SVC, pc, cpsr
 175         mov     r0, sp          @ save current stack into r0 (param register)
 176         .endm
 177
 178         .macro  irq_save_user_regs
 179         sub     sp, sp, #S_FRAME_SIZE
 180         stmia   sp, {r0 - r12}                  @ Calling r0-r12
 181         @ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
 182         add     r8, sp, #S_PC
 183         stmdb   r8, {sp, lr}^           @ Calling SP, LR
 184         str     lr, [r8, #0]            @ Save calling PC
 185         mrs     r6, spsr
 186         str     r6, [r8, #4]            @ Save CPSR
 187         str     r0, [r8, #8]            @ Save OLD_R0
 188         mov     r0, sp
 189         .endm
 190
 191         .macro  irq_restore_user_regs
 192         ldmia   sp, {r0 - lr}^                  @ Calling r0 - lr
 193         mov     r0, r0
 194         ldr     lr, [sp, #S_PC]                 @ Get PC
 195         add     sp, sp, #S_FRAME_SIZE
 196         subs    pc, lr, #4              @ return & move spsr_svc into cpsr
 197         .endm
 198
 199         .macro get_bad_stack
 200         ldr     r13, IRQ_STACK_START_IN         @ setup our mode stack
 201
 202         str     lr, [r13]       @ save caller lr in position 0 of saved stack
 203         mrs     lr, spsr        @ get the spsr
 204         str     lr, [r13, #4]   @ save spsr in position 1 of saved stack
 205         mov     r13, #MODE_SVC  @ prepare SVC-Mode
 206         @ msr   spsr_c, r13
 207         msr     spsr, r13       @ switch modes, make sure moves will execute
 208         mov     lr, pc          @ capture return pc
 209         movs    pc, lr          @ jump to next instruction & switch modes.
 210         .endm
 211
 212         .macro get_irq_stack                    @ setup IRQ stack
 213         ldr     sp, IRQ_STACK_START
 214         .endm
 215
 216         .macro get_fiq_stack                    @ setup FIQ stack
 217         ldr     sp, FIQ_STACK_START
 218         .endm
 219
 220 /*
 221  * exception handlers
 222  */
 223
 224         .align  5
 225 undefined_instruction:
 226         get_bad_stack
 227         bad_save_user_regs
 228         bl      do_undefined_instruction
 229
 230         .align  5
 231 software_interrupt:
 232         get_bad_stack
 233         bad_save_user_regs
 234         bl      do_software_interrupt
 235
 236         .align  5
 237 prefetch_abort:
 238         get_bad_stack
 239         bad_save_user_regs
 240         bl      do_prefetch_abort
 241
 242         .align  5
 243 data_abort:
 244         get_bad_stack
 245         bad_save_user_regs
 246         bl      do_data_abort
 247
 248         .align  5
 249 not_used:
 250         get_bad_stack
 251         bad_save_user_regs
 252         bl      do_not_used
 253
 254
 255         .align  5
 256 irq:
 257         get_bad_stack
 258         bad_save_user_regs
 259         bl      do_irq
 260
 261         .align  5
 262 fiq:
 263         get_bad_stack
 264         bad_save_user_regs
 265         bl      do_fiq
 266
 267 #endif  /* CONFIG_SPL_BUILD */