arch/openrisc/kernel/head.S

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   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * OpenRISC head.S
   4  *
   5  * Linux architectural port borrowing liberally from similar works of
   6  * others.  All original copyrights apply as per the original source
   7  * declaration.
   8  *
   9  * Modifications for the OpenRISC architecture:
  10  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  11  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  12  */
  13 
  14 #include <linux/linkage.h>
  15 #include <linux/threads.h>
  16 #include <linux/errno.h>
  17 #include <linux/init.h>
  18 #include <linux/serial_reg.h>
  19 #include <asm/processor.h>
  20 #include <asm/page.h>
  21 #include <asm/mmu.h>
  22 #include <asm/pgtable.h>
  23 #include <asm/thread_info.h>
  24 #include <asm/cache.h>
  25 #include <asm/spr_defs.h>
  26 #include <asm/asm-offsets.h>
  27 #include <linux/of_fdt.h>
  28 
  29 #define tophys(rd,rs)                           \
  30         l.movhi rd,hi(-KERNELBASE)              ;\
  31         l.add   rd,rd,rs
  32 
  33 #define CLEAR_GPR(gpr)                          \
  34         l.movhi gpr,0x0
  35 
  36 #define LOAD_SYMBOL_2_GPR(gpr,symbol)           \
  37         l.movhi gpr,hi(symbol)                  ;\
  38         l.ori   gpr,gpr,lo(symbol)
  39 
  40 
  41 #define UART_BASE_ADD      0x90000000
  42 
  43 #define EXCEPTION_SR  (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_SM)
  44 #define SYSCALL_SR  (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_IEE | SPR_SR_TEE | SPR_SR_SM)
  45 
  46 /* ============================================[ tmp store locations ]=== */
  47 
  48 #define SPR_SHADOW_GPR(x)       ((x) + SPR_GPR_BASE + 32)
  49 
  50 /*
  51  * emergency_print temporary stores
  52  */
  53 #ifdef CONFIG_OPENRISC_HAVE_SHADOW_GPRS
  54 #define EMERGENCY_PRINT_STORE_GPR4      l.mtspr r0,r4,SPR_SHADOW_GPR(14)
  55 #define EMERGENCY_PRINT_LOAD_GPR4       l.mfspr r4,r0,SPR_SHADOW_GPR(14)
  56 
  57 #define EMERGENCY_PRINT_STORE_GPR5      l.mtspr r0,r5,SPR_SHADOW_GPR(15)
  58 #define EMERGENCY_PRINT_LOAD_GPR5       l.mfspr r5,r0,SPR_SHADOW_GPR(15)
  59 
  60 #define EMERGENCY_PRINT_STORE_GPR6      l.mtspr r0,r6,SPR_SHADOW_GPR(16)
  61 #define EMERGENCY_PRINT_LOAD_GPR6       l.mfspr r6,r0,SPR_SHADOW_GPR(16)
  62 
  63 #define EMERGENCY_PRINT_STORE_GPR7      l.mtspr r0,r7,SPR_SHADOW_GPR(7)
  64 #define EMERGENCY_PRINT_LOAD_GPR7       l.mfspr r7,r0,SPR_SHADOW_GPR(7)
  65 
  66 #define EMERGENCY_PRINT_STORE_GPR8      l.mtspr r0,r8,SPR_SHADOW_GPR(8)
  67 #define EMERGENCY_PRINT_LOAD_GPR8       l.mfspr r8,r0,SPR_SHADOW_GPR(8)
  68 
  69 #define EMERGENCY_PRINT_STORE_GPR9      l.mtspr r0,r9,SPR_SHADOW_GPR(9)
  70 #define EMERGENCY_PRINT_LOAD_GPR9       l.mfspr r9,r0,SPR_SHADOW_GPR(9)
  71 
  72 #else /* !CONFIG_OPENRISC_HAVE_SHADOW_GPRS */
  73 #define EMERGENCY_PRINT_STORE_GPR4      l.sw    0x20(r0),r4
  74 #define EMERGENCY_PRINT_LOAD_GPR4       l.lwz   r4,0x20(r0)
  75 
  76 #define EMERGENCY_PRINT_STORE_GPR5      l.sw    0x24(r0),r5
  77 #define EMERGENCY_PRINT_LOAD_GPR5       l.lwz   r5,0x24(r0)
  78 
  79 #define EMERGENCY_PRINT_STORE_GPR6      l.sw    0x28(r0),r6
  80 #define EMERGENCY_PRINT_LOAD_GPR6       l.lwz   r6,0x28(r0)
  81 
  82 #define EMERGENCY_PRINT_STORE_GPR7      l.sw    0x2c(r0),r7
  83 #define EMERGENCY_PRINT_LOAD_GPR7       l.lwz   r7,0x2c(r0)
  84 
  85 #define EMERGENCY_PRINT_STORE_GPR8      l.sw    0x30(r0),r8
  86 #define EMERGENCY_PRINT_LOAD_GPR8       l.lwz   r8,0x30(r0)
  87 
  88 #define EMERGENCY_PRINT_STORE_GPR9      l.sw    0x34(r0),r9
  89 #define EMERGENCY_PRINT_LOAD_GPR9       l.lwz   r9,0x34(r0)
  90 
  91 #endif
  92 
  93 /*
  94  * TLB miss handlers temorary stores
  95  */
  96 #ifdef CONFIG_OPENRISC_HAVE_SHADOW_GPRS
  97 #define EXCEPTION_STORE_GPR2            l.mtspr r0,r2,SPR_SHADOW_GPR(2)
  98 #define EXCEPTION_LOAD_GPR2             l.mfspr r2,r0,SPR_SHADOW_GPR(2)
  99 
 100 #define EXCEPTION_STORE_GPR3            l.mtspr r0,r3,SPR_SHADOW_GPR(3)
 101 #define EXCEPTION_LOAD_GPR3             l.mfspr r3,r0,SPR_SHADOW_GPR(3)
 102 
 103 #define EXCEPTION_STORE_GPR4            l.mtspr r0,r4,SPR_SHADOW_GPR(4)
 104 #define EXCEPTION_LOAD_GPR4             l.mfspr r4,r0,SPR_SHADOW_GPR(4)
 105 
 106 #define EXCEPTION_STORE_GPR5            l.mtspr r0,r5,SPR_SHADOW_GPR(5)
 107 #define EXCEPTION_LOAD_GPR5             l.mfspr r5,r0,SPR_SHADOW_GPR(5)
 108 
 109 #define EXCEPTION_STORE_GPR6            l.mtspr r0,r6,SPR_SHADOW_GPR(6)
 110 #define EXCEPTION_LOAD_GPR6             l.mfspr r6,r0,SPR_SHADOW_GPR(6)
 111 
 112 #else /* !CONFIG_OPENRISC_HAVE_SHADOW_GPRS */
 113 #define EXCEPTION_STORE_GPR2            l.sw    0x64(r0),r2
 114 #define EXCEPTION_LOAD_GPR2             l.lwz   r2,0x64(r0)
 115 
 116 #define EXCEPTION_STORE_GPR3            l.sw    0x68(r0),r3
 117 #define EXCEPTION_LOAD_GPR3             l.lwz   r3,0x68(r0)
 118 
 119 #define EXCEPTION_STORE_GPR4            l.sw    0x6c(r0),r4
 120 #define EXCEPTION_LOAD_GPR4             l.lwz   r4,0x6c(r0)
 121 
 122 #define EXCEPTION_STORE_GPR5            l.sw    0x70(r0),r5
 123 #define EXCEPTION_LOAD_GPR5             l.lwz   r5,0x70(r0)
 124 
 125 #define EXCEPTION_STORE_GPR6            l.sw    0x74(r0),r6
 126 #define EXCEPTION_LOAD_GPR6             l.lwz   r6,0x74(r0)
 127 
 128 #endif
 129 
 130 /*
 131  * EXCEPTION_HANDLE temporary stores
 132  */
 133 
 134 #ifdef CONFIG_OPENRISC_HAVE_SHADOW_GPRS
 135 #define EXCEPTION_T_STORE_GPR30         l.mtspr r0,r30,SPR_SHADOW_GPR(30)
 136 #define EXCEPTION_T_LOAD_GPR30(reg)     l.mfspr reg,r0,SPR_SHADOW_GPR(30)
 137 
 138 #define EXCEPTION_T_STORE_GPR10         l.mtspr r0,r10,SPR_SHADOW_GPR(10)
 139 #define EXCEPTION_T_LOAD_GPR10(reg)     l.mfspr reg,r0,SPR_SHADOW_GPR(10)
 140 
 141 #define EXCEPTION_T_STORE_SP            l.mtspr r0,r1,SPR_SHADOW_GPR(1)
 142 #define EXCEPTION_T_LOAD_SP(reg)        l.mfspr reg,r0,SPR_SHADOW_GPR(1)
 143 
 144 #else /* !CONFIG_OPENRISC_HAVE_SHADOW_GPRS */
 145 #define EXCEPTION_T_STORE_GPR30         l.sw    0x78(r0),r30
 146 #define EXCEPTION_T_LOAD_GPR30(reg)     l.lwz   reg,0x78(r0)
 147 
 148 #define EXCEPTION_T_STORE_GPR10         l.sw    0x7c(r0),r10
 149 #define EXCEPTION_T_LOAD_GPR10(reg)     l.lwz   reg,0x7c(r0)
 150 
 151 #define EXCEPTION_T_STORE_SP            l.sw    0x80(r0),r1
 152 #define EXCEPTION_T_LOAD_SP(reg)        l.lwz   reg,0x80(r0)
 153 #endif
 154 
 155 /* =========================================================[ macros ]=== */
 156 
 157 #ifdef CONFIG_SMP
 158 #define GET_CURRENT_PGD(reg,t1)                                 \
 159         LOAD_SYMBOL_2_GPR(reg,current_pgd)                      ;\
 160         l.mfspr t1,r0,SPR_COREID                                ;\
 161         l.slli  t1,t1,2                                         ;\
 162         l.add   reg,reg,t1                                      ;\
 163         tophys  (t1,reg)                                        ;\
 164         l.lwz   reg,0(t1)
 165 #else
 166 #define GET_CURRENT_PGD(reg,t1)                                 \
 167         LOAD_SYMBOL_2_GPR(reg,current_pgd)                      ;\
 168         tophys  (t1,reg)                                        ;\
 169         l.lwz   reg,0(t1)
 170 #endif
 171 
 172 /* Load r10 from current_thread_info_set - clobbers r1 and r30 */
 173 #ifdef CONFIG_SMP
 174 #define GET_CURRENT_THREAD_INFO                                 \
 175         LOAD_SYMBOL_2_GPR(r1,current_thread_info_set)           ;\
 176         tophys  (r30,r1)                                        ;\
 177         l.mfspr r10,r0,SPR_COREID                               ;\
 178         l.slli  r10,r10,2                                       ;\
 179         l.add   r30,r30,r10                                     ;\
 180         /* r10: current_thread_info  */                         ;\
 181         l.lwz   r10,0(r30)
 182 #else
 183 #define GET_CURRENT_THREAD_INFO                                 \
 184         LOAD_SYMBOL_2_GPR(r1,current_thread_info_set)           ;\
 185         tophys  (r30,r1)                                        ;\
 186         /* r10: current_thread_info  */                         ;\
 187         l.lwz   r10,0(r30)
 188 #endif
 189 
 190 /*
 191  * DSCR: this is a common hook for handling exceptions. it will save
 192  *       the needed registers, set up stack and pointer to current
 193  *       then jump to the handler while enabling MMU
 194  *
 195  * PRMS: handler        - a function to jump to. it has to save the
 196  *                      remaining registers to kernel stack, call
 197  *                      appropriate arch-independant exception handler
 198  *                      and finaly jump to ret_from_except
 199  *
 200  * PREQ: unchanged state from the time exception happened
 201  *
 202  * POST: SAVED the following registers original value
 203  *             to the new created exception frame pointed to by r1
 204  *
 205  *       r1  - ksp      pointing to the new (exception) frame
 206  *       r4  - EEAR     exception EA
 207  *       r10 - current  pointing to current_thread_info struct
 208  *       r12 - syscall  0, since we didn't come from syscall
 209  *       r30 - handler  address of the handler we'll jump to
 210  *
 211  *       handler has to save remaining registers to the exception
 212  *       ksp frame *before* tainting them!
 213  *
 214  * NOTE: this function is not reentrant per se. reentrancy is guaranteed
 215  *       by processor disabling all exceptions/interrupts when exception
 216  *       accours.
 217  *
 218  * OPTM: no need to make it so wasteful to extract ksp when in user mode
 219  */
 220 
 221 #define EXCEPTION_HANDLE(handler)                               \
 222         EXCEPTION_T_STORE_GPR30                                 ;\
 223         l.mfspr r30,r0,SPR_ESR_BASE                             ;\
 224         l.andi  r30,r30,SPR_SR_SM                               ;\
 225         l.sfeqi r30,0                                           ;\
 226         EXCEPTION_T_STORE_GPR10                                 ;\
 227         l.bnf   2f                            /* kernel_mode */ ;\
 228          EXCEPTION_T_STORE_SP                 /* delay slot */  ;\
 229 1: /* user_mode:   */                                           ;\
 230         GET_CURRENT_THREAD_INFO                                 ;\
 231         tophys  (r30,r10)                                       ;\
 232         l.lwz   r1,(TI_KSP)(r30)                                ;\
 233         /* fall through */                                      ;\
 234 2: /* kernel_mode: */                                           ;\
 235         /* create new stack frame, save only needed gprs */     ;\
 236         /* r1: KSP, r10: current, r4: EEAR, r31: __pa(KSP) */   ;\
 237         /* r12: temp, syscall indicator */                      ;\
 238         l.addi  r1,r1,-(INT_FRAME_SIZE)                         ;\
 239         /* r1 is KSP, r30 is __pa(KSP) */                       ;\
 240         tophys  (r30,r1)                                        ;\
 241         l.sw    PT_GPR12(r30),r12                               ;\
 242         /* r4 use for tmp before EA */                          ;\
 243         l.mfspr r12,r0,SPR_EPCR_BASE                            ;\
 244         l.sw    PT_PC(r30),r12                                  ;\
 245         l.mfspr r12,r0,SPR_ESR_BASE                             ;\
 246         l.sw    PT_SR(r30),r12                                  ;\
 247         /* save r30 */                                          ;\
 248         EXCEPTION_T_LOAD_GPR30(r12)                             ;\
 249         l.sw    PT_GPR30(r30),r12                               ;\
 250         /* save r10 as was prior to exception */                ;\
 251         EXCEPTION_T_LOAD_GPR10(r12)                             ;\
 252         l.sw    PT_GPR10(r30),r12                               ;\
 253         /* save PT_SP as was prior to exception */              ;\
 254         EXCEPTION_T_LOAD_SP(r12)                                ;\
 255         l.sw    PT_SP(r30),r12                                  ;\
 256         /* save exception r4, set r4 = EA */                    ;\
 257         l.sw    PT_GPR4(r30),r4                                 ;\
 258         l.mfspr r4,r0,SPR_EEAR_BASE                             ;\
 259         /* r12 == 1 if we come from syscall */                  ;\
 260         CLEAR_GPR(r12)                                          ;\
 261         /* ----- turn on MMU ----- */                           ;\
 262         /* Carry DSX into exception SR */                       ;\
 263         l.mfspr r30,r0,SPR_SR                                   ;\
 264         l.andi  r30,r30,SPR_SR_DSX                              ;\
 265         l.ori   r30,r30,(EXCEPTION_SR)                          ;\
 266         l.mtspr r0,r30,SPR_ESR_BASE                             ;\
 267         /* r30: EA address of handler */                        ;\
 268         LOAD_SYMBOL_2_GPR(r30,handler)                          ;\
 269         l.mtspr r0,r30,SPR_EPCR_BASE                            ;\
 270         l.rfe
 271 
 272 /*
 273  * this doesn't work
 274  *
 275  *
 276  * #ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION
 277  * #define UNHANDLED_EXCEPTION(handler)                         \
 278  *      l.ori   r3,r0,0x1                                       ;\
 279  *      l.mtspr r0,r3,SPR_SR                                    ;\
 280  *      l.movhi r3,hi(0xf0000100)                               ;\
 281  *      l.ori   r3,r3,lo(0xf0000100)                            ;\
 282  *      l.jr    r3                                              ;\
 283  *      l.nop   1
 284  *
 285  * #endif
 286  */
 287 
 288 /* DSCR: this is the same as EXCEPTION_HANDLE(), we are just
 289  *       a bit more carefull (if we have a PT_SP or current pointer
 290  *       corruption) and set them up from 'current_set'
 291  *
 292  */
 293 #define UNHANDLED_EXCEPTION(handler)                            \
 294         EXCEPTION_T_STORE_GPR30                                 ;\
 295         EXCEPTION_T_STORE_GPR10                                 ;\
 296         EXCEPTION_T_STORE_SP                                    ;\
 297         /* temporary store r3, r9 into r1, r10 */               ;\
 298         l.addi  r1,r3,0x0                                       ;\
 299         l.addi  r10,r9,0x0                                      ;\
 300         /* the string referenced by r3 must be low enough */    ;\
 301         l.jal   _emergency_print                                ;\
 302         l.ori   r3,r0,lo(_string_unhandled_exception)           ;\
 303         l.mfspr r3,r0,SPR_NPC                                   ;\
 304         l.jal   _emergency_print_nr                             ;\
 305         l.andi  r3,r3,0x1f00                                    ;\
 306         /* the string referenced by r3 must be low enough */    ;\
 307         l.jal   _emergency_print                                ;\
 308         l.ori   r3,r0,lo(_string_epc_prefix)                    ;\
 309         l.jal   _emergency_print_nr                             ;\
 310         l.mfspr r3,r0,SPR_EPCR_BASE                             ;\
 311         l.jal   _emergency_print                                ;\
 312         l.ori   r3,r0,lo(_string_nl)                            ;\
 313         /* end of printing */                                   ;\
 314         l.addi  r3,r1,0x0                                       ;\
 315         l.addi  r9,r10,0x0                                      ;\
 316         /* extract current, ksp from current_set */             ;\
 317         LOAD_SYMBOL_2_GPR(r1,_unhandled_stack_top)              ;\
 318         LOAD_SYMBOL_2_GPR(r10,init_thread_union)                ;\
 319         /* create new stack frame, save only needed gprs */     ;\
 320         /* r1: KSP, r10: current, r31: __pa(KSP) */             ;\
 321         /* r12: temp, syscall indicator, r13 temp */            ;\
 322         l.addi  r1,r1,-(INT_FRAME_SIZE)                         ;\
 323         /* r1 is KSP, r30 is __pa(KSP) */                       ;\
 324         tophys  (r30,r1)                                        ;\
 325         l.sw    PT_GPR12(r30),r12                                       ;\
 326         l.mfspr r12,r0,SPR_EPCR_BASE                            ;\
 327         l.sw    PT_PC(r30),r12                                  ;\
 328         l.mfspr r12,r0,SPR_ESR_BASE                             ;\
 329         l.sw    PT_SR(r30),r12                                  ;\
 330         /* save r31 */                                          ;\
 331         EXCEPTION_T_LOAD_GPR30(r12)                             ;\
 332         l.sw    PT_GPR30(r30),r12                                       ;\
 333         /* save r10 as was prior to exception */                ;\
 334         EXCEPTION_T_LOAD_GPR10(r12)                             ;\
 335         l.sw    PT_GPR10(r30),r12                                       ;\
 336         /* save PT_SP as was prior to exception */                      ;\
 337         EXCEPTION_T_LOAD_SP(r12)                                ;\
 338         l.sw    PT_SP(r30),r12                                  ;\
 339         l.sw    PT_GPR13(r30),r13                                       ;\
 340         /* --> */                                               ;\
 341         /* save exception r4, set r4 = EA */                    ;\
 342         l.sw    PT_GPR4(r30),r4                                 ;\
 343         l.mfspr r4,r0,SPR_EEAR_BASE                             ;\
 344         /* r12 == 1 if we come from syscall */                  ;\
 345         CLEAR_GPR(r12)                                          ;\
 346         /* ----- play a MMU trick ----- */                      ;\
 347         l.ori   r30,r0,(EXCEPTION_SR)                           ;\
 348         l.mtspr r0,r30,SPR_ESR_BASE                             ;\
 349         /* r31: EA address of handler */                        ;\
 350         LOAD_SYMBOL_2_GPR(r30,handler)                          ;\
 351         l.mtspr r0,r30,SPR_EPCR_BASE                            ;\
 352         l.rfe
 353 
 354 /* =====================================================[ exceptions] === */
 355 
 356 /* ---[ 0x100: RESET exception ]----------------------------------------- */
 357     .org 0x100
 358         /* Jump to .init code at _start which lives in the .head section
 359          * and will be discarded after boot.
 360          */
 361         LOAD_SYMBOL_2_GPR(r15, _start)
 362         tophys  (r13,r15)                       /* MMU disabled */
 363         l.jr    r13
 364          l.nop
 365 
 366 /* ---[ 0x200: BUS exception ]------------------------------------------- */
 367     .org 0x200
 368 _dispatch_bus_fault:
 369         EXCEPTION_HANDLE(_bus_fault_handler)
 370 
 371 /* ---[ 0x300: Data Page Fault exception ]------------------------------- */
 372     .org 0x300
 373 _dispatch_do_dpage_fault:
 374 //      totaly disable timer interrupt
 375 //      l.mtspr r0,r0,SPR_TTMR
 376 //      DEBUG_TLB_PROBE(0x300)
 377 //      EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x300)
 378         EXCEPTION_HANDLE(_data_page_fault_handler)
 379 
 380 /* ---[ 0x400: Insn Page Fault exception ]------------------------------- */
 381     .org 0x400
 382 _dispatch_do_ipage_fault:
 383 //      totaly disable timer interrupt
 384 //      l.mtspr r0,r0,SPR_TTMR
 385 //      DEBUG_TLB_PROBE(0x400)
 386 //      EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x400)
 387         EXCEPTION_HANDLE(_insn_page_fault_handler)
 388 
 389 /* ---[ 0x500: Timer exception ]----------------------------------------- */
 390     .org 0x500
 391         EXCEPTION_HANDLE(_timer_handler)
 392 
 393 /* ---[ 0x600: Alignment exception ]-------------------------------------- */
 394     .org 0x600
 395         EXCEPTION_HANDLE(_alignment_handler)
 396 
 397 /* ---[ 0x700: Illegal insn exception ]---------------------------------- */
 398     .org 0x700
 399         EXCEPTION_HANDLE(_illegal_instruction_handler)
 400 
 401 /* ---[ 0x800: External interrupt exception ]---------------------------- */
 402     .org 0x800
 403         EXCEPTION_HANDLE(_external_irq_handler)
 404 
 405 /* ---[ 0x900: DTLB miss exception ]------------------------------------- */
 406     .org 0x900
 407         l.j     boot_dtlb_miss_handler
 408         l.nop
 409 
 410 /* ---[ 0xa00: ITLB miss exception ]------------------------------------- */
 411     .org 0xa00
 412         l.j     boot_itlb_miss_handler
 413         l.nop
 414 
 415 /* ---[ 0xb00: Range exception ]----------------------------------------- */
 416     .org 0xb00
 417         UNHANDLED_EXCEPTION(_vector_0xb00)
 418 
 419 /* ---[ 0xc00: Syscall exception ]--------------------------------------- */
 420     .org 0xc00
 421         EXCEPTION_HANDLE(_sys_call_handler)
 422 
 423 /* ---[ 0xd00: Trap exception ]------------------------------------------ */
 424     .org 0xd00
 425         UNHANDLED_EXCEPTION(_vector_0xd00)
 426 
 427 /* ---[ 0xe00: Trap exception ]------------------------------------------ */
 428     .org 0xe00
 429 //      UNHANDLED_EXCEPTION(_vector_0xe00)
 430         EXCEPTION_HANDLE(_trap_handler)
 431 
 432 /* ---[ 0xf00: Reserved exception ]-------------------------------------- */
 433     .org 0xf00
 434         UNHANDLED_EXCEPTION(_vector_0xf00)
 435 
 436 /* ---[ 0x1000: Reserved exception ]------------------------------------- */
 437     .org 0x1000
 438         UNHANDLED_EXCEPTION(_vector_0x1000)
 439 
 440 /* ---[ 0x1100: Reserved exception ]------------------------------------- */
 441     .org 0x1100
 442         UNHANDLED_EXCEPTION(_vector_0x1100)
 443 
 444 /* ---[ 0x1200: Reserved exception ]------------------------------------- */
 445     .org 0x1200
 446         UNHANDLED_EXCEPTION(_vector_0x1200)
 447 
 448 /* ---[ 0x1300: Reserved exception ]------------------------------------- */
 449     .org 0x1300
 450         UNHANDLED_EXCEPTION(_vector_0x1300)
 451 
 452 /* ---[ 0x1400: Reserved exception ]------------------------------------- */
 453     .org 0x1400
 454         UNHANDLED_EXCEPTION(_vector_0x1400)
 455 
 456 /* ---[ 0x1500: Reserved exception ]------------------------------------- */
 457     .org 0x1500
 458         UNHANDLED_EXCEPTION(_vector_0x1500)
 459 
 460 /* ---[ 0x1600: Reserved exception ]------------------------------------- */
 461     .org 0x1600
 462         UNHANDLED_EXCEPTION(_vector_0x1600)
 463 
 464 /* ---[ 0x1700: Reserved exception ]------------------------------------- */
 465     .org 0x1700
 466         UNHANDLED_EXCEPTION(_vector_0x1700)
 467 
 468 /* ---[ 0x1800: Reserved exception ]------------------------------------- */
 469     .org 0x1800
 470         UNHANDLED_EXCEPTION(_vector_0x1800)
 471 
 472 /* ---[ 0x1900: Reserved exception ]------------------------------------- */
 473     .org 0x1900
 474         UNHANDLED_EXCEPTION(_vector_0x1900)
 475 
 476 /* ---[ 0x1a00: Reserved exception ]------------------------------------- */
 477     .org 0x1a00
 478         UNHANDLED_EXCEPTION(_vector_0x1a00)
 479 
 480 /* ---[ 0x1b00: Reserved exception ]------------------------------------- */
 481     .org 0x1b00
 482         UNHANDLED_EXCEPTION(_vector_0x1b00)
 483 
 484 /* ---[ 0x1c00: Reserved exception ]------------------------------------- */
 485     .org 0x1c00
 486         UNHANDLED_EXCEPTION(_vector_0x1c00)
 487 
 488 /* ---[ 0x1d00: Reserved exception ]------------------------------------- */
 489     .org 0x1d00
 490         UNHANDLED_EXCEPTION(_vector_0x1d00)
 491 
 492 /* ---[ 0x1e00: Reserved exception ]------------------------------------- */
 493     .org 0x1e00
 494         UNHANDLED_EXCEPTION(_vector_0x1e00)
 495 
 496 /* ---[ 0x1f00: Reserved exception ]------------------------------------- */
 497     .org 0x1f00
 498         UNHANDLED_EXCEPTION(_vector_0x1f00)
 499 
 500     .org 0x2000
 501 /* ===================================================[ kernel start ]=== */
 502 
 503 /*    .text*/
 504 
 505 /* This early stuff belongs in HEAD, but some of the functions below definitely
 506  * don't... */
 507 
 508         __HEAD
 509         .global _start
 510 _start:
 511         /* Init r0 to zero as per spec */
 512         CLEAR_GPR(r0)
 513 
 514         /* save kernel parameters */
 515         l.or    r25,r0,r3       /* pointer to fdt */
 516 
 517         /*
 518          * ensure a deterministic start
 519          */
 520 
 521         l.ori   r3,r0,0x1
 522         l.mtspr r0,r3,SPR_SR
 523 
 524         CLEAR_GPR(r1)
 525         CLEAR_GPR(r2)
 526         CLEAR_GPR(r3)
 527         CLEAR_GPR(r4)
 528         CLEAR_GPR(r5)
 529         CLEAR_GPR(r6)
 530         CLEAR_GPR(r7)
 531         CLEAR_GPR(r8)
 532         CLEAR_GPR(r9)
 533         CLEAR_GPR(r10)
 534         CLEAR_GPR(r11)
 535         CLEAR_GPR(r12)
 536         CLEAR_GPR(r13)
 537         CLEAR_GPR(r14)
 538         CLEAR_GPR(r15)
 539         CLEAR_GPR(r16)
 540         CLEAR_GPR(r17)
 541         CLEAR_GPR(r18)
 542         CLEAR_GPR(r19)
 543         CLEAR_GPR(r20)
 544         CLEAR_GPR(r21)
 545         CLEAR_GPR(r22)
 546         CLEAR_GPR(r23)
 547         CLEAR_GPR(r24)
 548         CLEAR_GPR(r26)
 549         CLEAR_GPR(r27)
 550         CLEAR_GPR(r28)
 551         CLEAR_GPR(r29)
 552         CLEAR_GPR(r30)
 553         CLEAR_GPR(r31)
 554 
 555 #ifdef CONFIG_SMP
 556         l.mfspr r26,r0,SPR_COREID
 557         l.sfeq  r26,r0
 558         l.bnf   secondary_wait
 559          l.nop
 560 #endif
 561         /*
 562          * set up initial ksp and current
 563          */
 564         /* setup kernel stack */
 565         LOAD_SYMBOL_2_GPR(r1,init_thread_union + THREAD_SIZE)
 566         LOAD_SYMBOL_2_GPR(r10,init_thread_union)        // setup current
 567         tophys  (r31,r10)
 568         l.sw    TI_KSP(r31), r1
 569 
 570         l.ori   r4,r0,0x0
 571 
 572 
 573         /*
 574          * .data contains initialized data,
 575          * .bss contains uninitialized data - clear it up
 576          */
 577 clear_bss:
 578         LOAD_SYMBOL_2_GPR(r24, __bss_start)
 579         LOAD_SYMBOL_2_GPR(r26, _end)
 580         tophys(r28,r24)
 581         tophys(r30,r26)
 582         CLEAR_GPR(r24)
 583         CLEAR_GPR(r26)
 584 1:
 585         l.sw    (0)(r28),r0
 586         l.sfltu r28,r30
 587         l.bf    1b
 588         l.addi  r28,r28,4
 589 
 590 enable_ic:
 591         l.jal   _ic_enable
 592          l.nop
 593 
 594 enable_dc:
 595         l.jal   _dc_enable
 596          l.nop
 597 
 598 flush_tlb:
 599         l.jal   _flush_tlb
 600          l.nop
 601 
 602 /* The MMU needs to be enabled before or32_early_setup is called */
 603 
 604 enable_mmu:
 605         /*
 606          * enable dmmu & immu
 607          * SR[5] = 0, SR[6] = 0, 6th and 7th bit of SR set to 0
 608          */
 609         l.mfspr r30,r0,SPR_SR
 610         l.movhi r28,hi(SPR_SR_DME | SPR_SR_IME)
 611         l.ori   r28,r28,lo(SPR_SR_DME | SPR_SR_IME)
 612         l.or    r30,r30,r28
 613         l.mtspr r0,r30,SPR_SR
 614         l.nop
 615         l.nop
 616         l.nop
 617         l.nop
 618         l.nop
 619         l.nop
 620         l.nop
 621         l.nop
 622         l.nop
 623         l.nop
 624         l.nop
 625         l.nop
 626         l.nop
 627         l.nop
 628         l.nop
 629         l.nop
 630 
 631         // reset the simulation counters
 632         l.nop 5
 633 
 634         /* check fdt header magic word */
 635         l.lwz   r3,0(r25)       /* load magic from fdt into r3 */
 636         l.movhi r4,hi(OF_DT_HEADER)
 637         l.ori   r4,r4,lo(OF_DT_HEADER)
 638         l.sfeq  r3,r4
 639         l.bf    _fdt_found
 640          l.nop
 641         /* magic number mismatch, set fdt pointer to null */
 642         l.or    r25,r0,r0
 643 _fdt_found:
 644         /* pass fdt pointer to or32_early_setup in r3 */
 645         l.or    r3,r0,r25
 646         LOAD_SYMBOL_2_GPR(r24, or32_early_setup)
 647         l.jalr r24
 648          l.nop
 649 
 650 clear_regs:
 651         /*
 652          * clear all GPRS to increase determinism
 653          */
 654         CLEAR_GPR(r2)
 655         CLEAR_GPR(r3)
 656         CLEAR_GPR(r4)
 657         CLEAR_GPR(r5)
 658         CLEAR_GPR(r6)
 659         CLEAR_GPR(r7)
 660         CLEAR_GPR(r8)
 661         CLEAR_GPR(r9)
 662         CLEAR_GPR(r11)
 663         CLEAR_GPR(r12)
 664         CLEAR_GPR(r13)
 665         CLEAR_GPR(r14)
 666         CLEAR_GPR(r15)
 667         CLEAR_GPR(r16)
 668         CLEAR_GPR(r17)
 669         CLEAR_GPR(r18)
 670         CLEAR_GPR(r19)
 671         CLEAR_GPR(r20)
 672         CLEAR_GPR(r21)
 673         CLEAR_GPR(r22)
 674         CLEAR_GPR(r23)
 675         CLEAR_GPR(r24)
 676         CLEAR_GPR(r25)
 677         CLEAR_GPR(r26)
 678         CLEAR_GPR(r27)
 679         CLEAR_GPR(r28)
 680         CLEAR_GPR(r29)
 681         CLEAR_GPR(r30)
 682         CLEAR_GPR(r31)
 683 
 684 jump_start_kernel:
 685         /*
 686          * jump to kernel entry (start_kernel)
 687          */
 688         LOAD_SYMBOL_2_GPR(r30, start_kernel)
 689         l.jr    r30
 690          l.nop
 691 
 692 _flush_tlb:
 693         /*
 694          *  I N V A L I D A T E   T L B   e n t r i e s
 695          */
 696         LOAD_SYMBOL_2_GPR(r5,SPR_DTLBMR_BASE(0))
 697         LOAD_SYMBOL_2_GPR(r6,SPR_ITLBMR_BASE(0))
 698         l.addi  r7,r0,128 /* Maximum number of sets */
 699 1:
 700         l.mtspr r5,r0,0x0
 701         l.mtspr r6,r0,0x0
 702 
 703         l.addi  r5,r5,1
 704         l.addi  r6,r6,1
 705         l.sfeq  r7,r0
 706         l.bnf   1b
 707          l.addi r7,r7,-1
 708 
 709         l.jr    r9
 710          l.nop
 711 
 712 #ifdef CONFIG_SMP
 713 secondary_wait:
 714         /* Doze the cpu until we are asked to run */
 715         /* If we dont have power management skip doze */
 716         l.mfspr r25,r0,SPR_UPR
 717         l.andi  r25,r25,SPR_UPR_PMP
 718         l.sfeq  r25,r0
 719         l.bf    secondary_check_release
 720          l.nop
 721 
 722         /* Setup special secondary exception handler */
 723         LOAD_SYMBOL_2_GPR(r3, _secondary_evbar)
 724         tophys(r25,r3)
 725         l.mtspr r0,r25,SPR_EVBAR
 726 
 727         /* Enable Interrupts */
 728         l.mfspr r25,r0,SPR_SR
 729         l.ori   r25,r25,SPR_SR_IEE
 730         l.mtspr r0,r25,SPR_SR
 731 
 732         /* Unmask interrupts interrupts */
 733         l.mfspr r25,r0,SPR_PICMR
 734         l.ori   r25,r25,0xffff
 735         l.mtspr r0,r25,SPR_PICMR
 736 
 737         /* Doze */
 738         l.mfspr r25,r0,SPR_PMR
 739         LOAD_SYMBOL_2_GPR(r3, SPR_PMR_DME)
 740         l.or    r25,r25,r3
 741         l.mtspr r0,r25,SPR_PMR
 742 
 743         /* Wakeup - Restore exception handler */
 744         l.mtspr r0,r0,SPR_EVBAR
 745 
 746 secondary_check_release:
 747         /*
 748          * Check if we actually got the release signal, if not go-back to
 749          * sleep.
 750          */
 751         l.mfspr r25,r0,SPR_COREID
 752         LOAD_SYMBOL_2_GPR(r3, secondary_release)
 753         tophys(r4, r3)
 754         l.lwz   r3,0(r4)
 755         l.sfeq  r25,r3
 756         l.bnf   secondary_wait
 757          l.nop
 758         /* fall through to secondary_init */
 759 
 760 secondary_init:
 761         /*
 762          * set up initial ksp and current
 763          */
 764         LOAD_SYMBOL_2_GPR(r10, secondary_thread_info)
 765         tophys  (r30,r10)
 766         l.lwz   r10,0(r30)
 767         l.addi  r1,r10,THREAD_SIZE
 768         tophys  (r30,r10)
 769         l.sw    TI_KSP(r30),r1
 770 
 771         l.jal   _ic_enable
 772          l.nop
 773 
 774         l.jal   _dc_enable
 775          l.nop
 776 
 777         l.jal   _flush_tlb
 778          l.nop
 779 
 780         /*
 781          * enable dmmu & immu
 782          */
 783         l.mfspr r30,r0,SPR_SR
 784         l.movhi r28,hi(SPR_SR_DME | SPR_SR_IME)
 785         l.ori   r28,r28,lo(SPR_SR_DME | SPR_SR_IME)
 786         l.or    r30,r30,r28
 787         /*
 788          * This is a bit tricky, we need to switch over from physical addresses
 789          * to virtual addresses on the fly.
 790          * To do that, we first set up ESR with the IME and DME bits set.
 791          * Then EPCR is set to secondary_start and then a l.rfe is issued to
 792          * "jump" to that.
 793          */
 794         l.mtspr r0,r30,SPR_ESR_BASE
 795         LOAD_SYMBOL_2_GPR(r30, secondary_start)
 796         l.mtspr r0,r30,SPR_EPCR_BASE
 797         l.rfe
 798 
 799 secondary_start:
 800         LOAD_SYMBOL_2_GPR(r30, secondary_start_kernel)
 801         l.jr    r30
 802          l.nop
 803 
 804 #endif
 805 
 806 /* ========================================[ cache ]=== */
 807 
 808         /* alignment here so we don't change memory offsets with
 809          * memory controller defined
 810          */
 811         .align 0x2000
 812 
 813 _ic_enable:
 814         /* Check if IC present and skip enabling otherwise */
 815         l.mfspr r24,r0,SPR_UPR
 816         l.andi  r26,r24,SPR_UPR_ICP
 817         l.sfeq  r26,r0
 818         l.bf    9f
 819         l.nop
 820 
 821         /* Disable IC */
 822         l.mfspr r6,r0,SPR_SR
 823         l.addi  r5,r0,-1
 824         l.xori  r5,r5,SPR_SR_ICE
 825         l.and   r5,r6,r5
 826         l.mtspr r0,r5,SPR_SR
 827 
 828         /* Establish cache block size
 829            If BS=0, 16;
 830            If BS=1, 32;
 831            r14 contain block size
 832         */
 833         l.mfspr r24,r0,SPR_ICCFGR
 834         l.andi  r26,r24,SPR_ICCFGR_CBS
 835         l.srli  r28,r26,7
 836         l.ori   r30,r0,16
 837         l.sll   r14,r30,r28
 838 
 839         /* Establish number of cache sets
 840            r16 contains number of cache sets
 841            r28 contains log(# of cache sets)
 842         */
 843         l.andi  r26,r24,SPR_ICCFGR_NCS
 844         l.srli  r28,r26,3
 845         l.ori   r30,r0,1
 846         l.sll   r16,r30,r28
 847 
 848         /* Invalidate IC */
 849         l.addi  r6,r0,0
 850         l.sll   r5,r14,r28
 851 //        l.mul   r5,r14,r16
 852 //      l.trap  1
 853 //      l.addi  r5,r0,IC_SIZE
 854 1:
 855         l.mtspr r0,r6,SPR_ICBIR
 856         l.sfne  r6,r5
 857         l.bf    1b
 858         l.add   r6,r6,r14
 859  //       l.addi   r6,r6,IC_LINE
 860 
 861         /* Enable IC */
 862         l.mfspr r6,r0,SPR_SR
 863         l.ori   r6,r6,SPR_SR_ICE
 864         l.mtspr r0,r6,SPR_SR
 865         l.nop
 866         l.nop
 867         l.nop
 868         l.nop
 869         l.nop
 870         l.nop
 871         l.nop
 872         l.nop
 873         l.nop
 874         l.nop
 875 9:
 876         l.jr    r9
 877         l.nop
 878 
 879 _dc_enable:
 880         /* Check if DC present and skip enabling otherwise */
 881         l.mfspr r24,r0,SPR_UPR
 882         l.andi  r26,r24,SPR_UPR_DCP
 883         l.sfeq  r26,r0
 884         l.bf    9f
 885         l.nop
 886 
 887         /* Disable DC */
 888         l.mfspr r6,r0,SPR_SR
 889         l.addi  r5,r0,-1
 890         l.xori  r5,r5,SPR_SR_DCE
 891         l.and   r5,r6,r5
 892         l.mtspr r0,r5,SPR_SR
 893 
 894         /* Establish cache block size
 895            If BS=0, 16;
 896            If BS=1, 32;
 897            r14 contain block size
 898         */
 899         l.mfspr r24,r0,SPR_DCCFGR
 900         l.andi  r26,r24,SPR_DCCFGR_CBS
 901         l.srli  r28,r26,7
 902         l.ori   r30,r0,16
 903         l.sll   r14,r30,r28
 904 
 905         /* Establish number of cache sets
 906            r16 contains number of cache sets
 907            r28 contains log(# of cache sets)
 908         */
 909         l.andi  r26,r24,SPR_DCCFGR_NCS
 910         l.srli  r28,r26,3
 911         l.ori   r30,r0,1
 912         l.sll   r16,r30,r28
 913 
 914         /* Invalidate DC */
 915         l.addi  r6,r0,0
 916         l.sll   r5,r14,r28
 917 1:
 918         l.mtspr r0,r6,SPR_DCBIR
 919         l.sfne  r6,r5
 920         l.bf    1b
 921         l.add   r6,r6,r14
 922 
 923         /* Enable DC */
 924         l.mfspr r6,r0,SPR_SR
 925         l.ori   r6,r6,SPR_SR_DCE
 926         l.mtspr r0,r6,SPR_SR
 927 9:
 928         l.jr    r9
 929         l.nop
 930 
 931 /* ===============================================[ page table masks ]=== */
 932 
 933 #define DTLB_UP_CONVERT_MASK  0x3fa
 934 #define ITLB_UP_CONVERT_MASK  0x3a
 935 
 936 /* for SMP we'd have (this is a bit subtle, CC must be always set
 937  * for SMP, but since we have _PAGE_PRESENT bit always defined
 938  * we can just modify the mask)
 939  */
 940 #define DTLB_SMP_CONVERT_MASK  0x3fb
 941 #define ITLB_SMP_CONVERT_MASK  0x3b
 942 
 943 /* ---[ boot dtlb miss handler ]----------------------------------------- */
 944 
 945 boot_dtlb_miss_handler:
 946 
 947 /* mask for DTLB_MR register: - (0) sets V (valid) bit,
 948  *                            - (31-12) sets bits belonging to VPN (31-12)
 949  */
 950 #define DTLB_MR_MASK 0xfffff001
 951 
 952 /* mask for DTLB_TR register: - (2) sets CI (cache inhibit) bit,
 953  *                            - (4) sets A (access) bit,
 954  *                            - (5) sets D (dirty) bit,
 955  *                            - (8) sets SRE (superuser read) bit
 956  *                            - (9) sets SWE (superuser write) bit
 957  *                            - (31-12) sets bits belonging to VPN (31-12)
 958  */
 959 #define DTLB_TR_MASK 0xfffff332
 960 
 961 /* These are for masking out the VPN/PPN value from the MR/TR registers...
 962  * it's not the same as the PFN */
 963 #define VPN_MASK 0xfffff000
 964 #define PPN_MASK 0xfffff000
 965 
 966 
 967         EXCEPTION_STORE_GPR6
 968 
 969 #if 0
 970         l.mfspr r6,r0,SPR_ESR_BASE         //
 971         l.andi  r6,r6,SPR_SR_SM            // are we in kernel mode ?
 972         l.sfeqi r6,0                       // r6 == 0x1 --> SM
 973         l.bf    exit_with_no_dtranslation  //
 974         l.nop
 975 #endif
 976 
 977         /* this could be optimized by moving storing of
 978          * non r6 registers here, and jumping r6 restore
 979          * if not in supervisor mode
 980          */
 981 
 982         EXCEPTION_STORE_GPR2
 983         EXCEPTION_STORE_GPR3
 984         EXCEPTION_STORE_GPR4
 985         EXCEPTION_STORE_GPR5
 986 
 987         l.mfspr r4,r0,SPR_EEAR_BASE        // get the offending EA
 988 
 989 immediate_translation:
 990         CLEAR_GPR(r6)
 991 
 992         l.srli  r3,r4,0xd                  // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
 993 
 994         l.mfspr r6, r0, SPR_DMMUCFGR
 995         l.andi  r6, r6, SPR_DMMUCFGR_NTS
 996         l.srli  r6, r6, SPR_DMMUCFGR_NTS_OFF
 997         l.ori   r5, r0, 0x1
 998         l.sll   r5, r5, r6      // r5 = number DMMU sets
 999         l.addi  r6, r5, -1      // r6 = nsets mask
1000         l.and   r2, r3, r6      // r2 <- r3 % NSETS_MASK
1001 
1002         l.or    r6,r6,r4                   // r6 <- r4
1003         l.ori   r6,r6,~(VPN_MASK)          // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
1004         l.movhi r5,hi(DTLB_MR_MASK)        // r5 <- ffff:0000.x000
1005         l.ori   r5,r5,lo(DTLB_MR_MASK)     // r5 <- ffff:1111.x001 - apply DTLB_MR_MASK
1006         l.and   r5,r5,r6                   // r5 <- VPN :VPN .x001 - we have DTLBMR entry
1007         l.mtspr r2,r5,SPR_DTLBMR_BASE(0)   // set DTLBMR
1008 
1009         /* set up DTLB with no translation for EA <= 0xbfffffff */
1010         LOAD_SYMBOL_2_GPR(r6,0xbfffffff)
1011         l.sfgeu  r6,r4                     // flag if r6 >= r4 (if 0xbfffffff >= EA)
1012         l.bf     1f                        // goto out
1013         l.and    r3,r4,r4                  // delay slot :: 24 <- r4 (if flag==1)
1014 
1015         tophys(r3,r4)                      // r3 <- PA
1016 1:
1017         l.ori   r3,r3,~(PPN_MASK)          // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
1018         l.movhi r5,hi(DTLB_TR_MASK)        // r5 <- ffff:0000.x000
1019         l.ori   r5,r5,lo(DTLB_TR_MASK)     // r5 <- ffff:1111.x330 - apply DTLB_MR_MASK
1020         l.and   r5,r5,r3                   // r5 <- PPN :PPN .x330 - we have DTLBTR entry
1021         l.mtspr r2,r5,SPR_DTLBTR_BASE(0)   // set DTLBTR
1022 
1023         EXCEPTION_LOAD_GPR6
1024         EXCEPTION_LOAD_GPR5
1025         EXCEPTION_LOAD_GPR4
1026         EXCEPTION_LOAD_GPR3
1027         EXCEPTION_LOAD_GPR2
1028 
1029         l.rfe                              // SR <- ESR, PC <- EPC
1030 
1031 exit_with_no_dtranslation:
1032         /* EA out of memory or not in supervisor mode */
1033         EXCEPTION_LOAD_GPR6
1034         EXCEPTION_LOAD_GPR4
1035         l.j     _dispatch_bus_fault
1036 
1037 /* ---[ boot itlb miss handler ]----------------------------------------- */
1038 
1039 boot_itlb_miss_handler:
1040 
1041 /* mask for ITLB_MR register: - sets V (valid) bit,
1042  *                            - sets bits belonging to VPN (15-12)
1043  */
1044 #define ITLB_MR_MASK 0xfffff001
1045 
1046 /* mask for ITLB_TR register: - sets A (access) bit,
1047  *                            - sets SXE (superuser execute) bit
1048  *                            - sets bits belonging to VPN (15-12)
1049  */
1050 #define ITLB_TR_MASK 0xfffff050
1051 
1052 /*
1053 #define VPN_MASK 0xffffe000
1054 #define PPN_MASK 0xffffe000
1055 */
1056 
1057 
1058 
1059         EXCEPTION_STORE_GPR2
1060         EXCEPTION_STORE_GPR3
1061         EXCEPTION_STORE_GPR4
1062         EXCEPTION_STORE_GPR5
1063         EXCEPTION_STORE_GPR6
1064 
1065 #if 0
1066         l.mfspr r6,r0,SPR_ESR_BASE         //
1067         l.andi  r6,r6,SPR_SR_SM            // are we in kernel mode ?
1068         l.sfeqi r6,0                       // r6 == 0x1 --> SM
1069         l.bf    exit_with_no_itranslation
1070         l.nop
1071 #endif
1072 
1073 
1074         l.mfspr r4,r0,SPR_EEAR_BASE        // get the offending EA
1075 
1076 earlyearly:
1077         CLEAR_GPR(r6)
1078 
1079         l.srli  r3,r4,0xd                  // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
1080 
1081         l.mfspr r6, r0, SPR_IMMUCFGR
1082         l.andi  r6, r6, SPR_IMMUCFGR_NTS
1083         l.srli  r6, r6, SPR_IMMUCFGR_NTS_OFF
1084         l.ori   r5, r0, 0x1
1085         l.sll   r5, r5, r6      // r5 = number IMMU sets from IMMUCFGR
1086         l.addi  r6, r5, -1      // r6 = nsets mask
1087         l.and   r2, r3, r6      // r2 <- r3 % NSETS_MASK
1088 
1089         l.or    r6,r6,r4                   // r6 <- r4
1090         l.ori   r6,r6,~(VPN_MASK)          // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
1091         l.movhi r5,hi(ITLB_MR_MASK)        // r5 <- ffff:0000.x000
1092         l.ori   r5,r5,lo(ITLB_MR_MASK)     // r5 <- ffff:1111.x001 - apply ITLB_MR_MASK
1093         l.and   r5,r5,r6                   // r5 <- VPN :VPN .x001 - we have ITLBMR entry
1094         l.mtspr r2,r5,SPR_ITLBMR_BASE(0)   // set ITLBMR
1095 
1096         /*
1097          * set up ITLB with no translation for EA <= 0x0fffffff
1098          *
1099          * we need this for head.S mapping (EA = PA). if we move all functions
1100          * which run with mmu enabled into entry.S, we might be able to eliminate this.
1101          *
1102          */
1103         LOAD_SYMBOL_2_GPR(r6,0x0fffffff)
1104         l.sfgeu  r6,r4                     // flag if r6 >= r4 (if 0xb0ffffff >= EA)
1105         l.bf     1f                        // goto out
1106         l.and    r3,r4,r4                  // delay slot :: 24 <- r4 (if flag==1)
1107 
1108         tophys(r3,r4)                      // r3 <- PA
1109 1:
1110         l.ori   r3,r3,~(PPN_MASK)          // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
1111         l.movhi r5,hi(ITLB_TR_MASK)        // r5 <- ffff:0000.x000
1112         l.ori   r5,r5,lo(ITLB_TR_MASK)     // r5 <- ffff:1111.x050 - apply ITLB_MR_MASK
1113         l.and   r5,r5,r3                   // r5 <- PPN :PPN .x050 - we have ITLBTR entry
1114         l.mtspr r2,r5,SPR_ITLBTR_BASE(0)   // set ITLBTR
1115 
1116         EXCEPTION_LOAD_GPR6
1117         EXCEPTION_LOAD_GPR5
1118         EXCEPTION_LOAD_GPR4
1119         EXCEPTION_LOAD_GPR3
1120         EXCEPTION_LOAD_GPR2
1121 
1122         l.rfe                              // SR <- ESR, PC <- EPC
1123 
1124 exit_with_no_itranslation:
1125         EXCEPTION_LOAD_GPR4
1126         EXCEPTION_LOAD_GPR6
1127         l.j    _dispatch_bus_fault
1128         l.nop
1129 
1130 /* ====================================================================== */
1131 /*
1132  * Stuff below here shouldn't go into .head section... maybe this stuff
1133  * can be moved to entry.S ???
1134  */
1135 
1136 /* ==============================================[ DTLB miss handler ]=== */
1137 
1138 /*
1139  * Comments:
1140  *   Exception handlers are entered with MMU off so the following handler
1141  *   needs to use physical addressing
1142  *
1143  */
1144 
1145         .text
1146 ENTRY(dtlb_miss_handler)
1147         EXCEPTION_STORE_GPR2
1148         EXCEPTION_STORE_GPR3
1149         EXCEPTION_STORE_GPR4
1150         /*
1151          * get EA of the miss
1152          */
1153         l.mfspr r2,r0,SPR_EEAR_BASE
1154         /*
1155          * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
1156          */
1157         GET_CURRENT_PGD(r3,r4)          // r3 is current_pgd, r4 is temp
1158         l.srli  r4,r2,0x18              // >> PAGE_SHIFT + (PAGE_SHIFT - 2)
1159         l.slli  r4,r4,0x2               // to get address << 2
1160         l.add   r3,r4,r3                // r4 is pgd_index(daddr)
1161         /*
1162          * if (pmd_none(*pmd))
1163          *   goto pmd_none:
1164          */
1165         tophys  (r4,r3)
1166         l.lwz   r3,0x0(r4)              // get *pmd value
1167         l.sfne  r3,r0
1168         l.bnf   d_pmd_none
1169          l.addi r3,r0,0xffffe000        // PAGE_MASK
1170 
1171 d_pmd_good:
1172         /*
1173          * pte = *pte_offset(pmd, daddr);
1174          */
1175         l.lwz   r4,0x0(r4)              // get **pmd value
1176         l.and   r4,r4,r3                // & PAGE_MASK
1177         l.srli  r2,r2,0xd               // >> PAGE_SHIFT, r2 == EEAR
1178         l.andi  r3,r2,0x7ff             // (1UL << PAGE_SHIFT - 2) - 1
1179         l.slli  r3,r3,0x2               // to get address << 2
1180         l.add   r3,r3,r4
1181         l.lwz   r3,0x0(r3)              // this is pte at last
1182         /*
1183          * if (!pte_present(pte))
1184          */
1185         l.andi  r4,r3,0x1
1186         l.sfne  r4,r0                   // is pte present
1187         l.bnf   d_pte_not_present
1188         l.addi  r4,r0,0xffffe3fa        // PAGE_MASK | DTLB_UP_CONVERT_MASK
1189         /*
1190          * fill DTLB TR register
1191          */
1192         l.and   r4,r3,r4                // apply the mask
1193         // Determine number of DMMU sets
1194         l.mfspr r2, r0, SPR_DMMUCFGR
1195         l.andi  r2, r2, SPR_DMMUCFGR_NTS
1196         l.srli  r2, r2, SPR_DMMUCFGR_NTS_OFF
1197         l.ori   r3, r0, 0x1
1198         l.sll   r3, r3, r2      // r3 = number DMMU sets DMMUCFGR
1199         l.addi  r2, r3, -1      // r2 = nsets mask
1200         l.mfspr r3, r0, SPR_EEAR_BASE
1201         l.srli  r3, r3, 0xd     // >> PAGE_SHIFT
1202         l.and   r2, r3, r2      // calc offset:  & (NUM_TLB_ENTRIES-1)
1203                                                            //NUM_TLB_ENTRIES
1204         l.mtspr r2,r4,SPR_DTLBTR_BASE(0)
1205         /*
1206          * fill DTLB MR register
1207          */
1208         l.slli  r3, r3, 0xd             /* << PAGE_SHIFT => EA & PAGE_MASK */
1209         l.ori   r4,r3,0x1               // set hardware valid bit: DTBL_MR entry
1210         l.mtspr r2,r4,SPR_DTLBMR_BASE(0)
1211 
1212         EXCEPTION_LOAD_GPR2
1213         EXCEPTION_LOAD_GPR3
1214         EXCEPTION_LOAD_GPR4
1215         l.rfe
1216 d_pmd_none:
1217 d_pte_not_present:
1218         EXCEPTION_LOAD_GPR2
1219         EXCEPTION_LOAD_GPR3
1220         EXCEPTION_LOAD_GPR4
1221         EXCEPTION_HANDLE(_dtlb_miss_page_fault_handler)
1222 
1223 /* ==============================================[ ITLB miss handler ]=== */
1224 ENTRY(itlb_miss_handler)
1225         EXCEPTION_STORE_GPR2
1226         EXCEPTION_STORE_GPR3
1227         EXCEPTION_STORE_GPR4
1228         /*
1229          * get EA of the miss
1230          */
1231         l.mfspr r2,r0,SPR_EEAR_BASE
1232 
1233         /*
1234          * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
1235          *
1236          */
1237         GET_CURRENT_PGD(r3,r4)          // r3 is current_pgd, r5 is temp
1238         l.srli  r4,r2,0x18              // >> PAGE_SHIFT + (PAGE_SHIFT - 2)
1239         l.slli  r4,r4,0x2               // to get address << 2
1240         l.add   r3,r4,r3                // r4 is pgd_index(daddr)
1241         /*
1242          * if (pmd_none(*pmd))
1243          *   goto pmd_none:
1244          */
1245         tophys  (r4,r3)
1246         l.lwz   r3,0x0(r4)              // get *pmd value
1247         l.sfne  r3,r0
1248         l.bnf   i_pmd_none
1249          l.addi r3,r0,0xffffe000        // PAGE_MASK
1250 
1251 i_pmd_good:
1252         /*
1253          * pte = *pte_offset(pmd, iaddr);
1254          *
1255          */
1256         l.lwz   r4,0x0(r4)              // get **pmd value
1257         l.and   r4,r4,r3                // & PAGE_MASK
1258         l.srli  r2,r2,0xd               // >> PAGE_SHIFT, r2 == EEAR
1259         l.andi  r3,r2,0x7ff             // (1UL << PAGE_SHIFT - 2) - 1
1260         l.slli  r3,r3,0x2               // to get address << 2
1261         l.add   r3,r3,r4
1262         l.lwz   r3,0x0(r3)              // this is pte at last
1263         /*
1264          * if (!pte_present(pte))
1265          *
1266          */
1267         l.andi  r4,r3,0x1
1268         l.sfne  r4,r0                   // is pte present
1269         l.bnf   i_pte_not_present
1270          l.addi r4,r0,0xffffe03a        // PAGE_MASK | ITLB_UP_CONVERT_MASK
1271         /*
1272          * fill ITLB TR register
1273          */
1274         l.and   r4,r3,r4                // apply the mask
1275         l.andi  r3,r3,0x7c0             // _PAGE_EXEC | _PAGE_SRE | _PAGE_SWE |  _PAGE_URE | _PAGE_UWE
1276         l.sfeq  r3,r0
1277         l.bf    itlb_tr_fill //_workaround
1278         // Determine number of IMMU sets
1279         l.mfspr r2, r0, SPR_IMMUCFGR
1280         l.andi  r2, r2, SPR_IMMUCFGR_NTS
1281         l.srli  r2, r2, SPR_IMMUCFGR_NTS_OFF
1282         l.ori   r3, r0, 0x1
1283         l.sll   r3, r3, r2      // r3 = number IMMU sets IMMUCFGR
1284         l.addi  r2, r3, -1      // r2 = nsets mask
1285         l.mfspr r3, r0, SPR_EEAR_BASE
1286         l.srli  r3, r3, 0xd     // >> PAGE_SHIFT
1287         l.and   r2, r3, r2      // calc offset:  & (NUM_TLB_ENTRIES-1)
1288 
1289 /*
1290  * __PHX__ :: fixme
1291  * we should not just blindly set executable flags,
1292  * but it does help with ping. the clean way would be to find out
1293  * (and fix it) why stack doesn't have execution permissions
1294  */
1295 
1296 itlb_tr_fill_workaround:
1297         l.ori   r4,r4,0xc0              // | (SPR_ITLBTR_UXE | ITLBTR_SXE)
1298 itlb_tr_fill:
1299         l.mtspr r2,r4,SPR_ITLBTR_BASE(0)
1300         /*
1301          * fill DTLB MR register
1302          */
1303         l.slli  r3, r3, 0xd             /* << PAGE_SHIFT => EA & PAGE_MASK */
1304         l.ori   r4,r3,0x1               // set hardware valid bit: ITBL_MR entry
1305         l.mtspr r2,r4,SPR_ITLBMR_BASE(0)
1306 
1307         EXCEPTION_LOAD_GPR2
1308         EXCEPTION_LOAD_GPR3
1309         EXCEPTION_LOAD_GPR4
1310         l.rfe
1311 
1312 i_pmd_none:
1313 i_pte_not_present:
1314         EXCEPTION_LOAD_GPR2
1315         EXCEPTION_LOAD_GPR3
1316         EXCEPTION_LOAD_GPR4
1317         EXCEPTION_HANDLE(_itlb_miss_page_fault_handler)
1318 
1319 /* ==============================================[ boot tlb handlers ]=== */
1320 
1321 
1322 /* =================================================[ debugging aids ]=== */
1323 
1324         .align 64
1325 _immu_trampoline:
1326         .space 64
1327 _immu_trampoline_top:
1328 
1329 #define TRAMP_SLOT_0            (0x0)
1330 #define TRAMP_SLOT_1            (0x4)
1331 #define TRAMP_SLOT_2            (0x8)
1332 #define TRAMP_SLOT_3            (0xc)
1333 #define TRAMP_SLOT_4            (0x10)
1334 #define TRAMP_SLOT_5            (0x14)
1335 #define TRAMP_FRAME_SIZE        (0x18)
1336 
1337 ENTRY(_immu_trampoline_workaround)
1338         // r2 EEA
1339         // r6 is physical EEA
1340         tophys(r6,r2)
1341 
1342         LOAD_SYMBOL_2_GPR(r5,_immu_trampoline)
1343         tophys  (r3,r5)                 // r3 is trampoline (physical)
1344 
1345         LOAD_SYMBOL_2_GPR(r4,0x15000000)
1346         l.sw    TRAMP_SLOT_0(r3),r4
1347         l.sw    TRAMP_SLOT_1(r3),r4
1348         l.sw    TRAMP_SLOT_4(r3),r4
1349         l.sw    TRAMP_SLOT_5(r3),r4
1350 
1351                                         // EPC = EEA - 0x4
1352         l.lwz   r4,0x0(r6)              // load op @ EEA + 0x0 (fc address)
1353         l.sw    TRAMP_SLOT_3(r3),r4     // store it to _immu_trampoline_data
1354         l.lwz   r4,-0x4(r6)             // load op @ EEA - 0x4 (f8 address)
1355         l.sw    TRAMP_SLOT_2(r3),r4     // store it to _immu_trampoline_data
1356 
1357         l.srli  r5,r4,26                // check opcode for write access
1358         l.sfeqi r5,0                    // l.j
1359         l.bf    0f
1360         l.sfeqi r5,0x11                 // l.jr
1361         l.bf    1f
1362         l.sfeqi r5,1                    // l.jal
1363         l.bf    2f
1364         l.sfeqi r5,0x12                 // l.jalr
1365         l.bf    3f
1366         l.sfeqi r5,3                    // l.bnf
1367         l.bf    4f
1368         l.sfeqi r5,4                    // l.bf
1369         l.bf    5f
1370 99:
1371         l.nop
1372         l.j     99b                     // should never happen
1373         l.nop   1
1374 
1375         // r2 is EEA
1376         // r3 is trampoline address (physical)
1377         // r4 is instruction
1378         // r6 is physical(EEA)
1379         //
1380         // r5
1381 
1382 2:      // l.jal
1383 
1384         /* 19 20 aa aa  l.movhi r9,0xaaaa
1385          * a9 29 bb bb  l.ori   r9,0xbbbb
1386          *
1387          * where 0xaaaabbbb is EEA + 0x4 shifted right 2
1388          */
1389 
1390         l.addi  r6,r2,0x4               // this is 0xaaaabbbb
1391 
1392                                         // l.movhi r9,0xaaaa
1393         l.ori   r5,r0,0x1920            // 0x1920 == l.movhi r9
1394         l.sh    (TRAMP_SLOT_0+0x0)(r3),r5
1395         l.srli  r5,r6,16
1396         l.sh    (TRAMP_SLOT_0+0x2)(r3),r5
1397 
1398                                         // l.ori   r9,0xbbbb
1399         l.ori   r5,r0,0xa929            // 0xa929 == l.ori r9
1400         l.sh    (TRAMP_SLOT_1+0x0)(r3),r5
1401         l.andi  r5,r6,0xffff
1402         l.sh    (TRAMP_SLOT_1+0x2)(r3),r5
1403 
1404         /* falthrough, need to set up new jump offset */
1405 
1406 
1407 0:      // l.j
1408         l.slli  r6,r4,6                 // original offset shifted left 6 - 2
1409 //      l.srli  r6,r6,6                 // original offset shifted right 2
1410 
1411         l.slli  r4,r2,4                 // old jump position: EEA shifted left 4
1412 //      l.srli  r4,r4,6                 // old jump position: shifted right 2
1413 
1414         l.addi  r5,r3,0xc               // new jump position (physical)
1415         l.slli  r5,r5,4                 // new jump position: shifted left 4
1416 
1417         // calculate new jump offset
1418         // new_off = old_off + (old_jump - new_jump)
1419 
1420         l.sub   r5,r4,r5                // old_jump - new_jump
1421         l.add   r5,r6,r5                // orig_off + (old_jump - new_jump)
1422         l.srli  r5,r5,6                 // new offset shifted right 2
1423 
1424         // r5 is new jump offset
1425                                         // l.j has opcode 0x0...
1426         l.sw    TRAMP_SLOT_2(r3),r5     // write it back
1427 
1428         l.j     trampoline_out
1429         l.nop
1430 
1431 /* ----------------------------- */
1432 
1433 3:      // l.jalr
1434 
1435         /* 19 20 aa aa  l.movhi r9,0xaaaa
1436          * a9 29 bb bb  l.ori   r9,0xbbbb
1437          *
1438          * where 0xaaaabbbb is EEA + 0x4 shifted right 2
1439          */
1440 
1441         l.addi  r6,r2,0x4               // this is 0xaaaabbbb
1442 
1443                                         // l.movhi r9,0xaaaa
1444         l.ori   r5,r0,0x1920            // 0x1920 == l.movhi r9
1445         l.sh    (TRAMP_SLOT_0+0x0)(r3),r5
1446         l.srli  r5,r6,16
1447         l.sh    (TRAMP_SLOT_0+0x2)(r3),r5
1448 
1449                                         // l.ori   r9,0xbbbb
1450         l.ori   r5,r0,0xa929            // 0xa929 == l.ori r9
1451         l.sh    (TRAMP_SLOT_1+0x0)(r3),r5
1452         l.andi  r5,r6,0xffff
1453         l.sh    (TRAMP_SLOT_1+0x2)(r3),r5
1454 
1455         l.lhz   r5,(TRAMP_SLOT_2+0x0)(r3)       // load hi part of jump instruction
1456         l.andi  r5,r5,0x3ff             // clear out opcode part
1457         l.ori   r5,r5,0x4400            // opcode changed from l.jalr -> l.jr
1458         l.sh    (TRAMP_SLOT_2+0x0)(r3),r5 // write it back
1459 
1460         /* falthrough */
1461 
1462 1:      // l.jr
1463         l.j     trampoline_out
1464         l.nop
1465 
1466 /* ----------------------------- */
1467 
1468 4:      // l.bnf
1469 5:      // l.bf
1470         l.slli  r6,r4,6                 // original offset shifted left 6 - 2
1471 //      l.srli  r6,r6,6                 // original offset shifted right 2
1472 
1473         l.slli  r4,r2,4                 // old jump position: EEA shifted left 4
1474 //      l.srli  r4,r4,6                 // old jump position: shifted right 2
1475 
1476         l.addi  r5,r3,0xc               // new jump position (physical)
1477         l.slli  r5,r5,4                 // new jump position: shifted left 4
1478 
1479         // calculate new jump offset
1480         // new_off = old_off + (old_jump - new_jump)
1481 
1482         l.add   r6,r6,r4                // (orig_off + old_jump)
1483         l.sub   r6,r6,r5                // (orig_off + old_jump) - new_jump
1484         l.srli  r6,r6,6                 // new offset shifted right 2
1485 
1486         // r6 is new jump offset
1487         l.lwz   r4,(TRAMP_SLOT_2+0x0)(r3)       // load jump instruction
1488         l.srli  r4,r4,16
1489         l.andi  r4,r4,0xfc00            // get opcode part
1490         l.slli  r4,r4,16
1491         l.or    r6,r4,r6                // l.b(n)f new offset
1492         l.sw    TRAMP_SLOT_2(r3),r6     // write it back
1493 
1494         /* we need to add l.j to EEA + 0x8 */
1495         tophys  (r4,r2)                 // may not be needed (due to shifts down_
1496         l.addi  r4,r4,(0x8 - 0x8)       // jump target = r2 + 0x8 (compensate for 0x8)
1497                                         // jump position = r5 + 0x8 (0x8 compensated)
1498         l.sub   r4,r4,r5                // jump offset = target - new_position + 0x8
1499 
1500         l.slli  r4,r4,4                 // the amount of info in imediate of jump
1501         l.srli  r4,r4,6                 // jump instruction with offset
1502         l.sw    TRAMP_SLOT_4(r3),r4     // write it to 4th slot
1503 
1504         /* fallthrough */
1505 
1506 trampoline_out:
1507         // set up new EPC to point to our trampoline code
1508         LOAD_SYMBOL_2_GPR(r5,_immu_trampoline)
1509         l.mtspr r0,r5,SPR_EPCR_BASE
1510 
1511         // immu_trampoline is (4x) CACHE_LINE aligned
1512         // and only 6 instructions long,
1513         // so we need to invalidate only 2 lines
1514 
1515         /* Establish cache block size
1516            If BS=0, 16;
1517            If BS=1, 32;
1518            r14 contain block size
1519         */
1520         l.mfspr r21,r0,SPR_ICCFGR
1521         l.andi  r21,r21,SPR_ICCFGR_CBS
1522         l.srli  r21,r21,7
1523         l.ori   r23,r0,16
1524         l.sll   r14,r23,r21
1525 
1526         l.mtspr r0,r5,SPR_ICBIR
1527         l.add   r5,r5,r14
1528         l.mtspr r0,r5,SPR_ICBIR
1529 
1530         l.jr    r9
1531         l.nop
1532 
1533 
1534 /*
1535  * DSCR: prints a string referenced by r3.
1536  *
1537  * PRMS: r3             - address of the first character of null
1538  *                      terminated string to be printed
1539  *
1540  * PREQ: UART at UART_BASE_ADD has to be initialized
1541  *
1542  * POST: caller should be aware that r3, r9 are changed
1543  */
1544 ENTRY(_emergency_print)
1545         EMERGENCY_PRINT_STORE_GPR4
1546         EMERGENCY_PRINT_STORE_GPR5
1547         EMERGENCY_PRINT_STORE_GPR6
1548         EMERGENCY_PRINT_STORE_GPR7
1549 2:
1550         l.lbz   r7,0(r3)
1551         l.sfeq  r7,r0
1552         l.bf    9f
1553         l.nop
1554 
1555 // putc:
1556         l.movhi r4,hi(UART_BASE_ADD)
1557 
1558         l.addi  r6,r0,0x20
1559 1:      l.lbz   r5,5(r4)
1560         l.andi  r5,r5,0x20
1561         l.sfeq  r5,r6
1562         l.bnf   1b
1563         l.nop
1564 
1565         l.sb    0(r4),r7
1566 
1567         l.addi  r6,r0,0x60
1568 1:      l.lbz   r5,5(r4)
1569         l.andi  r5,r5,0x60
1570         l.sfeq  r5,r6
1571         l.bnf   1b
1572         l.nop
1573 
1574         /* next character */
1575         l.j     2b
1576         l.addi  r3,r3,0x1
1577 
1578 9:
1579         EMERGENCY_PRINT_LOAD_GPR7
1580         EMERGENCY_PRINT_LOAD_GPR6
1581         EMERGENCY_PRINT_LOAD_GPR5
1582         EMERGENCY_PRINT_LOAD_GPR4
1583         l.jr    r9
1584         l.nop
1585 
1586 ENTRY(_emergency_print_nr)
1587         EMERGENCY_PRINT_STORE_GPR4
1588         EMERGENCY_PRINT_STORE_GPR5
1589         EMERGENCY_PRINT_STORE_GPR6
1590         EMERGENCY_PRINT_STORE_GPR7
1591         EMERGENCY_PRINT_STORE_GPR8
1592 
1593         l.addi  r8,r0,32                // shift register
1594 
1595 1:      /* remove leading zeros */
1596         l.addi  r8,r8,-0x4
1597         l.srl   r7,r3,r8
1598         l.andi  r7,r7,0xf
1599 
1600         /* don't skip the last zero if number == 0x0 */
1601         l.sfeqi r8,0x4
1602         l.bf    2f
1603         l.nop
1604 
1605         l.sfeq  r7,r0
1606         l.bf    1b
1607         l.nop
1608 
1609 2:
1610         l.srl   r7,r3,r8
1611 
1612         l.andi  r7,r7,0xf
1613         l.sflts r8,r0
1614         l.bf    9f
1615 
1616         l.sfgtui r7,0x9
1617         l.bnf   8f
1618         l.nop
1619         l.addi  r7,r7,0x27
1620 
1621 8:
1622         l.addi  r7,r7,0x30
1623 // putc:
1624         l.movhi r4,hi(UART_BASE_ADD)
1625 
1626         l.addi  r6,r0,0x20
1627 1:      l.lbz   r5,5(r4)
1628         l.andi  r5,r5,0x20
1629         l.sfeq  r5,r6
1630         l.bnf   1b
1631         l.nop
1632 
1633         l.sb    0(r4),r7
1634 
1635         l.addi  r6,r0,0x60
1636 1:      l.lbz   r5,5(r4)
1637         l.andi  r5,r5,0x60
1638         l.sfeq  r5,r6
1639         l.bnf   1b
1640         l.nop
1641 
1642         /* next character */
1643         l.j     2b
1644         l.addi  r8,r8,-0x4
1645 
1646 9:
1647         EMERGENCY_PRINT_LOAD_GPR8
1648         EMERGENCY_PRINT_LOAD_GPR7
1649         EMERGENCY_PRINT_LOAD_GPR6
1650         EMERGENCY_PRINT_LOAD_GPR5
1651         EMERGENCY_PRINT_LOAD_GPR4
1652         l.jr    r9
1653         l.nop
1654 
1655 
1656 /*
1657  * This should be used for debugging only.
1658  * It messes up the Linux early serial output
1659  * somehow, so use it sparingly and essentially
1660  * only if you need to debug something that goes wrong
1661  * before Linux gets the early serial going.
1662  *
1663  * Furthermore, you'll have to make sure you set the
1664  * UART_DEVISOR correctly according to the system
1665  * clock rate.
1666  *
1667  *
1668  */
1669 
1670 
1671 
1672 #define SYS_CLK            20000000
1673 //#define SYS_CLK            1843200
1674 #define OR32_CONSOLE_BAUD  115200
1675 #define UART_DIVISOR       SYS_CLK/(16*OR32_CONSOLE_BAUD)
1676 
1677 ENTRY(_early_uart_init)
1678         l.movhi r3,hi(UART_BASE_ADD)
1679 
1680         l.addi  r4,r0,0x7
1681         l.sb    0x2(r3),r4
1682 
1683         l.addi  r4,r0,0x0
1684         l.sb    0x1(r3),r4
1685 
1686         l.addi  r4,r0,0x3
1687         l.sb    0x3(r3),r4
1688 
1689         l.lbz   r5,3(r3)
1690         l.ori   r4,r5,0x80
1691         l.sb    0x3(r3),r4
1692         l.addi  r4,r0,((UART_DIVISOR>>8) & 0x000000ff)
1693         l.sb    UART_DLM(r3),r4
1694         l.addi  r4,r0,((UART_DIVISOR) & 0x000000ff)
1695         l.sb    UART_DLL(r3),r4
1696         l.sb    0x3(r3),r5
1697 
1698         l.jr    r9
1699         l.nop
1700 
1701         .align  0x1000
1702         .global _secondary_evbar
1703 _secondary_evbar:
1704 
1705         .space 0x800
1706         /* Just disable interrupts and Return */
1707         l.ori   r3,r0,SPR_SR_SM
1708         l.mtspr r0,r3,SPR_ESR_BASE
1709         l.rfe
1710 
1711 
1712         .section .rodata
1713 _string_unhandled_exception:
1714         .string "\n\rRunarunaround: Unhandled exception 0x\0"
1715 
1716 _string_epc_prefix:
1717         .string ": EPC=0x\0"
1718 
1719 _string_nl:
1720         .string "\n\r\0"
1721 
1722 
1723 /* ========================================[ page aligned structures ]=== */
1724 
1725 /*
1726  * .data section should be page aligned
1727  *      (look into arch/openrisc/kernel/vmlinux.lds.S)
1728  */
1729         .section .data,"aw"
1730         .align  8192
1731         .global  empty_zero_page
1732 empty_zero_page:
1733         .space  8192
1734 
1735         .global  swapper_pg_dir
1736 swapper_pg_dir:
1737         .space  8192
1738 
1739         .global _unhandled_stack
1740 _unhandled_stack:
1741         .space  8192
1742 _unhandled_stack_top:
1743 
1744 /* ============================================================[ EOF ]=== */
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