arch/arc/cpu/arcv2/start.S

   1 /*
   2  * Copyright (C) 2013-2015 Synopsys, Inc. All rights reserved.
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <asm-offsets.h>
   8 #include <config.h>
   9 #include <asm/arcregs.h>
  10
  11 /*
  12  * Note on the LD/ST addressing modes with address register write-back
  13  *
  14  * LD.a same as LD.aw
  15  *
  16  * LD.a    reg1, [reg2, x]  => Pre Incr
  17  *      Eff Addr for load = [reg2 + x]
  18  *
  19  * LD.ab   reg1, [reg2, x]  => Post Incr
  20  *      Eff Addr for load = [reg2]
  21  */
  22
  23 .macro PUSH reg
  24         st.a    \reg, [%sp, -4]
  25 .endm
  26
  27 .macro PUSHAX aux
  28         lr      %r9, [\aux]
  29         PUSH    %r9
  30 .endm
  31
  32 .macro  SAVE_R1_TO_R24
  33         PUSH    %r1
  34         PUSH    %r2
  35         PUSH    %r3
  36         PUSH    %r4
  37         PUSH    %r5
  38         PUSH    %r6
  39         PUSH    %r7
  40         PUSH    %r8
  41         PUSH    %r9
  42         PUSH    %r10
  43         PUSH    %r11
  44         PUSH    %r12
  45         PUSH    %r13
  46         PUSH    %r14
  47         PUSH    %r15
  48         PUSH    %r16
  49         PUSH    %r17
  50         PUSH    %r18
  51         PUSH    %r19
  52         PUSH    %r20
  53         PUSH    %r21
  54         PUSH    %r22
  55         PUSH    %r23
  56         PUSH    %r24
  57 .endm
  58
  59 .macro SAVE_ALL_SYS
  60         /* saving %r0 to reg->r0 in advance since weread %ecr into it */
  61         st      %r0, [%sp, -8]
  62         lr      %r0, [%ecr]     /* all stack addressing is manual so far */
  63         st      %r0, [%sp]
  64         st      %sp, [%sp, -4]
  65         /* now move %sp to reg->r0 position so we can do "push" automatically */
  66         sub     %sp, %sp, 8
  67
  68         SAVE_R1_TO_R24
  69         PUSH    %r25
  70         PUSH    %gp
  71         PUSH    %fp
  72         PUSH    %blink
  73         PUSHAX  %eret
  74         PUSHAX  %erstatus
  75         PUSH    %lp_count
  76         PUSHAX  %lp_end
  77         PUSHAX  %lp_start
  78         PUSHAX  %erbta
  79 .endm
  80
  81 .macro SAVE_EXCEPTION_SOURCE
  82 #ifdef CONFIG_MMU
  83         /* If MMU exists exception faulting address is loaded in EFA reg */
  84         lr      %r0, [%efa]
  85 #else
  86         /* Otherwise in ERET (exception return) reg */
  87         lr      %r0, [%eret]
  88 #endif
  89 .endm
  90
  91 .section .ivt, "a",@progbits
  92 .align 4
  93         /* Critical system events */
  94 .word   _start                  /* 0 - 0x000 */
  95 .word   memory_error            /* 1 - 0x008 */
  96 .word   instruction_error       /* 2 - 0x010 */
  97
  98         /* Exceptions */
  99 .word   EV_MachineCheck         /* 0x100, Fatal Machine check  (0x20) */
 100 .word   EV_TLBMissI             /* 0x108, Intruction TLB miss  (0x21) */
 101 .word   EV_TLBMissD             /* 0x110, Data TLB miss        (0x22) */
 102 .word   EV_TLBProtV             /* 0x118, Protection Violation (0x23)
 103                                                         or Misaligned Access  */
 104 .word   EV_PrivilegeV           /* 0x120, Privilege Violation  (0x24) */
 105 .word   EV_Trap                 /* 0x128, Trap exception       (0x25) */
 106 .word   EV_Extension            /* 0x130, Extn Intruction Excp (0x26) */
 107
 108         /* Device interrupts */
 109 .rept   29
 110         j       interrupt_handler       /* 3:31 - 0x018:0xF8 */
 111 .endr
 112
 113 .text
 114 .globl _start
 115 _start:
 116         /* Setup interrupt vector base that matches "__text_start" */
 117         sr      __ivt_start, [ARC_AUX_INTR_VEC_BASE]
 118
 119         /* Setup stack pointer */
 120         mov     %sp, CONFIG_SYS_INIT_SP_ADDR
 121         mov     %fp, %sp
 122
 123         /* Clear bss */
 124         mov     %r0, __bss_start
 125         mov     %r1, __bss_end
 126
 127 clear_bss:
 128         st.ab   0, [%r0, 4]
 129         brlt    %r0, %r1, clear_bss
 130
 131         /* Zero the one and only argument of "board_init_f" */
 132         mov_s   %r0, 0
 133         j       board_init_f
 134
 135 memory_error:
 136         SAVE_ALL_SYS
 137         SAVE_EXCEPTION_SOURCE
 138         mov     %r1, %sp
 139         j       do_memory_error
 140
 141 instruction_error:
 142         SAVE_ALL_SYS
 143         SAVE_EXCEPTION_SOURCE
 144         mov     %r1, %sp
 145         j       do_instruction_error
 146
 147 interrupt_handler:
 148         /* Todo - save and restore CPU context when interrupts will be in use */
 149         bl      do_interrupt_handler
 150         rtie
 151
 152 EV_MachineCheck:
 153         SAVE_ALL_SYS
 154         SAVE_EXCEPTION_SOURCE
 155         mov     %r1, %sp
 156         j       do_machine_check_fault
 157
 158 EV_TLBMissI:
 159         SAVE_ALL_SYS
 160         mov     %r0, %sp
 161         j       do_itlb_miss
 162
 163 EV_TLBMissD:
 164         SAVE_ALL_SYS
 165         mov     %r0, %sp
 166         j       do_dtlb_miss
 167
 168 EV_TLBProtV:
 169         SAVE_ALL_SYS
 170         SAVE_EXCEPTION_SOURCE
 171         mov     %r1, %sp
 172         j       do_tlb_prot_violation
 173
 174 EV_PrivilegeV:
 175         SAVE_ALL_SYS
 176         mov     %r0, %sp
 177         j       do_privilege_violation
 178
 179 EV_Trap:
 180         SAVE_ALL_SYS
 181         mov     %r0, %sp
 182         j       do_trap
 183
 184 EV_Extension:
 185         SAVE_ALL_SYS
 186         mov     %r0, %sp
 187         j       do_extension
 188
 189 /*
 190  * void relocate_code (addr_sp, gd, addr_moni)
 191  *
 192  * This "function" does not return, instead it continues in RAM
 193  * after relocating the monitor code.
 194  *
 195  * r0 = start_addr_sp
 196  * r1 = new__gd
 197  * r2 = relocaddr
 198  */
 199 .align 4
 200 .globl  relocate_code
 201 relocate_code:
 202         /*
 203          * r0-r12 might be clobbered by C functions
 204          * so we use r13-r16 for storage here
 205          */
 206         mov     %r13, %r0               /* save addr_sp */
 207         mov     %r14, %r1               /* save addr of gd */
 208         mov     %r15, %r2               /* save addr of destination */
 209
 210         mov     %r16, %r2               /* %r9 - relocation offset */
 211         sub     %r16, %r16, __image_copy_start
 212
 213 /* Set up the stack */
 214 stack_setup:
 215         mov     %sp, %r13
 216         mov     %fp, %sp
 217
 218 /* Check if monitor is loaded right in place for relocation */
 219         mov     %r0, __image_copy_start
 220         cmp     %r0, %r15               /* skip relocation if code loaded */
 221         bz      do_board_init_r         /* in target location already */
 222
 223 /* Copy data (__image_copy_start - __image_copy_end) to new location */
 224         mov     %r1, %r15
 225         mov     %r2, __image_copy_end
 226         sub     %r2, %r2, %r0           /* r3 <- amount of bytes to copy */
 227         asr     %r2, %r2, 2             /* r3 <- amount of words to copy */
 228         mov     %lp_count, %r2
 229         lp      copy_end
 230         ld.ab   %r2,[%r0,4]
 231         st.ab   %r2,[%r1,4]
 232 copy_end:
 233
 234 /* Fix relocations related issues */
 235         bl      do_elf_reloc_fixups
 236 #ifndef CONFIG_SYS_ICACHE_OFF
 237         bl      invalidate_icache_all
 238 #endif
 239 #ifndef CONFIG_SYS_DCACHE_OFF
 240         bl      flush_dcache_all
 241 #endif
 242
 243 /* Update position of intterupt vector table */
 244         lr      %r0, [ARC_AUX_INTR_VEC_BASE]    /* Read current position */
 245         add     %r0, %r0, %r16                  /* Update address */
 246         sr      %r0, [ARC_AUX_INTR_VEC_BASE]    /* Write new position */
 247
 248 do_board_init_r:
 249 /* Prepare for exection of "board_init_r" in relocated monitor */
 250         mov     %r2, board_init_r       /* old address of "board_init_r()" */
 251         add     %r2, %r2, %r16          /* new address of "board_init_r()" */
 252         mov     %r0, %r14               /* 1-st parameter: gd_t */
 253         mov     %r1, %r15               /* 2-nd parameter: dest_addr */
 254         j       [%r2]