arch/openrisc/kernel/head.S

   1 /*
   2  * OpenRISC head.S
   3  *
   4  * Linux architectural port borrowing liberally from similar works of
   5  * others.  All original copyrights apply as per the original source
   6  * declaration.
   7  *
   8  * Modifications for the OpenRISC architecture:
   9  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  10  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  */
  17
  18 #include <linux/linkage.h>
  19 #include <linux/threads.h>
  20 #include <linux/errno.h>
  21 #include <linux/init.h>
  22 #include <asm/processor.h>
  23 #include <asm/page.h>
  24 #include <asm/mmu.h>
  25 #include <asm/pgtable.h>
  26 #include <asm/cache.h>
  27 #include <asm/spr_defs.h>
  28 #include <asm/asm-offsets.h>
  29
  30 #define tophys(rd,rs)                           \
  31         l.movhi rd,hi(-KERNELBASE)              ;\
  32         l.add   rd,rd,rs
  33
  34 #define CLEAR_GPR(gpr)                          \
  35         l.or    gpr,r0,r0
  36
  37 #define LOAD_SYMBOL_2_GPR(gpr,symbol)           \
  38         l.movhi gpr,hi(symbol)                  ;\
  39         l.ori   gpr,gpr,lo(symbol)
  40
  41
  42 #define UART_BASE_ADD      0x90000000
  43
  44 #define EXCEPTION_SR  (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_SM)
  45 #define SYSCALL_SR  (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_IEE | SPR_SR_TEE | SPR_SR_SM)
  46
  47 /* ============================================[ tmp store locations ]=== */
  48
  49 /*
  50  * emergency_print temporary stores
  51  */
  52 #define EMERGENCY_PRINT_STORE_GPR4      l.sw    0x20(r0),r4
  53 #define EMERGENCY_PRINT_LOAD_GPR4       l.lwz   r4,0x20(r0)
  54
  55 #define EMERGENCY_PRINT_STORE_GPR5      l.sw    0x24(r0),r5
  56 #define EMERGENCY_PRINT_LOAD_GPR5       l.lwz   r5,0x24(r0)
  57
  58 #define EMERGENCY_PRINT_STORE_GPR6      l.sw    0x28(r0),r6
  59 #define EMERGENCY_PRINT_LOAD_GPR6       l.lwz   r6,0x28(r0)
  60
  61 #define EMERGENCY_PRINT_STORE_GPR7      l.sw    0x2c(r0),r7
  62 #define EMERGENCY_PRINT_LOAD_GPR7       l.lwz   r7,0x2c(r0)
  63
  64 #define EMERGENCY_PRINT_STORE_GPR8      l.sw    0x30(r0),r8
  65 #define EMERGENCY_PRINT_LOAD_GPR8       l.lwz   r8,0x30(r0)
  66
  67 #define EMERGENCY_PRINT_STORE_GPR9      l.sw    0x34(r0),r9
  68 #define EMERGENCY_PRINT_LOAD_GPR9       l.lwz   r9,0x34(r0)
  69
  70
  71 /*
  72  * TLB miss handlers temorary stores
  73  */
  74 #define EXCEPTION_STORE_GPR9            l.sw    0x10(r0),r9
  75 #define EXCEPTION_LOAD_GPR9             l.lwz   r9,0x10(r0)
  76
  77 #define EXCEPTION_STORE_GPR2            l.sw    0x64(r0),r2
  78 #define EXCEPTION_LOAD_GPR2             l.lwz   r2,0x64(r0)
  79
  80 #define EXCEPTION_STORE_GPR3            l.sw    0x68(r0),r3
  81 #define EXCEPTION_LOAD_GPR3             l.lwz   r3,0x68(r0)
  82
  83 #define EXCEPTION_STORE_GPR4            l.sw    0x6c(r0),r4
  84 #define EXCEPTION_LOAD_GPR4             l.lwz   r4,0x6c(r0)
  85
  86 #define EXCEPTION_STORE_GPR5            l.sw    0x70(r0),r5
  87 #define EXCEPTION_LOAD_GPR5             l.lwz   r5,0x70(r0)
  88
  89 #define EXCEPTION_STORE_GPR6            l.sw    0x74(r0),r6
  90 #define EXCEPTION_LOAD_GPR6             l.lwz   r6,0x74(r0)
  91
  92
  93 /*
  94  * EXCEPTION_HANDLE temporary stores
  95  */
  96
  97 #define EXCEPTION_T_STORE_GPR30         l.sw    0x78(r0),r30
  98 #define EXCEPTION_T_LOAD_GPR30(reg)     l.lwz   reg,0x78(r0)
  99
 100 #define EXCEPTION_T_STORE_GPR10         l.sw    0x7c(r0),r10
 101 #define EXCEPTION_T_LOAD_GPR10(reg)     l.lwz   reg,0x7c(r0)
 102
 103 #define EXCEPTION_T_STORE_SP            l.sw    0x80(r0),r1
 104 #define EXCEPTION_T_LOAD_SP(reg)        l.lwz   reg,0x80(r0)
 105
 106 /*
 107  * For UNHANLDED_EXCEPTION
 108  */
 109
 110 #define EXCEPTION_T_STORE_GPR31         l.sw    0x84(r0),r31
 111 #define EXCEPTION_T_LOAD_GPR31(reg)     l.lwz   reg,0x84(r0)
 112
 113 /* =========================================================[ macros ]=== */
 114
 115
 116 #define GET_CURRENT_PGD(reg,t1)                                 \
 117         LOAD_SYMBOL_2_GPR(reg,current_pgd)                      ;\
 118         tophys  (t1,reg)                                        ;\
 119         l.lwz   reg,0(t1)
 120
 121
 122 /*
 123  * DSCR: this is a common hook for handling exceptions. it will save
 124  *       the needed registers, set up stack and pointer to current
 125  *       then jump to the handler while enabling MMU
 126  *
 127  * PRMS: handler        - a function to jump to. it has to save the
 128  *                      remaining registers to kernel stack, call
 129  *                      appropriate arch-independant exception handler
 130  *                      and finaly jump to ret_from_except
 131  *
 132  * PREQ: unchanged state from the time exception happened
 133  *
 134  * POST: SAVED the following registers original value
 135  *             to the new created exception frame pointed to by r1
 136  *
 137  *       r1  - ksp      pointing to the new (exception) frame
 138  *       r4  - EEAR     exception EA
 139  *       r10 - current  pointing to current_thread_info struct
 140  *       r12 - syscall  0, since we didn't come from syscall
 141  *       r13 - temp     it actually contains new SR, not needed anymore
 142  *       r31 - handler  address of the handler we'll jump to
 143  *
 144  *       handler has to save remaining registers to the exception
 145  *       ksp frame *before* tainting them!
 146  *
 147  * NOTE: this function is not reentrant per se. reentrancy is guaranteed
 148  *       by processor disabling all exceptions/interrupts when exception
 149  *       accours.
 150  *
 151  * OPTM: no need to make it so wasteful to extract ksp when in user mode
 152  */
 153
 154 #define EXCEPTION_HANDLE(handler)                               \
 155         EXCEPTION_T_STORE_GPR30                                 ;\
 156         l.mfspr r30,r0,SPR_ESR_BASE                             ;\
 157         l.andi  r30,r30,SPR_SR_SM                               ;\
 158         l.sfeqi r30,0                                           ;\
 159         EXCEPTION_T_STORE_GPR10                                 ;\
 160         l.bnf   2f                            /* kernel_mode */ ;\
 161          EXCEPTION_T_STORE_SP                 /* delay slot */  ;\
 162 1: /* user_mode:   */                                           ;\
 163         LOAD_SYMBOL_2_GPR(r1,current_thread_info_set)           ;\
 164         tophys  (r30,r1)                                        ;\
 165         /* r10: current_thread_info  */                         ;\
 166         l.lwz   r10,0(r30)                                      ;\
 167         tophys  (r30,r10)                                       ;\
 168         l.lwz   r1,(TI_KSP)(r30)                                ;\
 169         /* fall through */                                      ;\
 170 2: /* kernel_mode: */                                           ;\
 171         /* create new stack frame, save only needed gprs */     ;\
 172         /* r1: KSP, r10: current, r4: EEAR, r31: __pa(KSP) */   ;\
 173         /* r12: temp, syscall indicator */                      ;\
 174         l.addi  r1,r1,-(INT_FRAME_SIZE)                         ;\
 175         /* r1 is KSP, r30 is __pa(KSP) */                       ;\
 176         tophys  (r30,r1)                                        ;\
 177         l.sw    PT_GPR12(r30),r12                               ;\
 178         l.mfspr r12,r0,SPR_EPCR_BASE                            ;\
 179         l.sw    PT_PC(r30),r12                                  ;\
 180         l.mfspr r12,r0,SPR_ESR_BASE                             ;\
 181         l.sw    PT_SR(r30),r12                                  ;\
 182         /* save r30 */                                          ;\
 183         EXCEPTION_T_LOAD_GPR30(r12)                             ;\
 184         l.sw    PT_GPR30(r30),r12                               ;\
 185         /* save r10 as was prior to exception */                ;\
 186         EXCEPTION_T_LOAD_GPR10(r12)                             ;\
 187         l.sw    PT_GPR10(r30),r12                               ;\
 188         /* save PT_SP as was prior to exception */              ;\
 189         EXCEPTION_T_LOAD_SP(r12)                                ;\
 190         l.sw    PT_SP(r30),r12                                  ;\
 191         /* save exception r4, set r4 = EA */                    ;\
 192         l.sw    PT_GPR4(r30),r4                                 ;\
 193         l.mfspr r4,r0,SPR_EEAR_BASE                             ;\
 194         /* r12 == 1 if we come from syscall */                  ;\
 195         CLEAR_GPR(r12)                                          ;\
 196         /* ----- turn on MMU ----- */                           ;\
 197         l.ori   r30,r0,(EXCEPTION_SR)                           ;\
 198         l.mtspr r0,r30,SPR_ESR_BASE                             ;\
 199         /* r30: EA address of handler */                        ;\
 200         LOAD_SYMBOL_2_GPR(r30,handler)                          ;\
 201         l.mtspr r0,r30,SPR_EPCR_BASE                            ;\
 202         l.rfe
 203
 204 /*
 205  * this doesn't work
 206  *
 207  *
 208  * #ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION
 209  * #define UNHANDLED_EXCEPTION(handler)                         \
 210  *      l.ori   r3,r0,0x1                                       ;\
 211  *      l.mtspr r0,r3,SPR_SR                                    ;\
 212  *      l.movhi r3,hi(0xf0000100)                               ;\
 213  *      l.ori   r3,r3,lo(0xf0000100)                            ;\
 214  *      l.jr    r3                                              ;\
 215  *      l.nop   1
 216  *
 217  * #endif
 218  */
 219
 220 /* DSCR: this is the same as EXCEPTION_HANDLE(), we are just
 221  *       a bit more carefull (if we have a PT_SP or current pointer
 222  *       corruption) and set them up from 'current_set'
 223  *
 224  */
 225 #define UNHANDLED_EXCEPTION(handler)                            \
 226         EXCEPTION_T_STORE_GPR31                                 ;\
 227         EXCEPTION_T_STORE_GPR10                                 ;\
 228         EXCEPTION_T_STORE_SP                                    ;\
 229         /* temporary store r3, r9 into r1, r10 */               ;\
 230         l.addi  r1,r3,0x0                                       ;\
 231         l.addi  r10,r9,0x0                                      ;\
 232         /* the string referenced by r3 must be low enough */    ;\
 233         l.jal   _emergency_print                                ;\
 234         l.ori   r3,r0,lo(_string_unhandled_exception)           ;\
 235         l.mfspr r3,r0,SPR_NPC                                   ;\
 236         l.jal   _emergency_print_nr                             ;\
 237         l.andi  r3,r3,0x1f00                                    ;\
 238         /* the string referenced by r3 must be low enough */    ;\
 239         l.jal   _emergency_print                                ;\
 240         l.ori   r3,r0,lo(_string_epc_prefix)                    ;\
 241         l.jal   _emergency_print_nr                             ;\
 242         l.mfspr r3,r0,SPR_EPCR_BASE                             ;\
 243         l.jal   _emergency_print                                ;\
 244         l.ori   r3,r0,lo(_string_nl)                            ;\
 245         /* end of printing */                                   ;\
 246         l.addi  r3,r1,0x0                                       ;\
 247         l.addi  r9,r10,0x0                                      ;\
 248         /* extract current, ksp from current_set */             ;\
 249         LOAD_SYMBOL_2_GPR(r1,_unhandled_stack_top)              ;\
 250         LOAD_SYMBOL_2_GPR(r10,init_thread_union)                ;\
 251         /* create new stack frame, save only needed gprs */     ;\
 252         /* r1: KSP, r10: current, r31: __pa(KSP) */             ;\
 253         /* r12: temp, syscall indicator, r13 temp */            ;\
 254         l.addi  r1,r1,-(INT_FRAME_SIZE)                         ;\
 255         /* r1 is KSP, r31 is __pa(KSP) */                       ;\
 256         tophys  (r31,r1)                                        ;\
 257         l.sw    PT_GPR12(r31),r12                                       ;\
 258         l.mfspr r12,r0,SPR_EPCR_BASE                            ;\
 259         l.sw    PT_PC(r31),r12                                  ;\
 260         l.mfspr r12,r0,SPR_ESR_BASE                             ;\
 261         l.sw    PT_SR(r31),r12                                  ;\
 262         /* save r31 */                                          ;\
 263         EXCEPTION_T_LOAD_GPR31(r12)                             ;\
 264         l.sw    PT_GPR31(r31),r12                                       ;\
 265         /* save r10 as was prior to exception */                ;\
 266         EXCEPTION_T_LOAD_GPR10(r12)                             ;\
 267         l.sw    PT_GPR10(r31),r12                                       ;\
 268         /* save PT_SP as was prior to exception */                      ;\
 269         EXCEPTION_T_LOAD_SP(r12)                                ;\
 270         l.sw    PT_SP(r31),r12                                  ;\
 271         l.sw    PT_GPR13(r31),r13                                       ;\
 272         /* --> */                                               ;\
 273         /* save exception r4, set r4 = EA */                    ;\
 274         l.sw    PT_GPR4(r31),r4                                 ;\
 275         l.mfspr r4,r0,SPR_EEAR_BASE                             ;\
 276         /* r12 == 1 if we come from syscall */                  ;\
 277         CLEAR_GPR(r12)                                          ;\
 278         /* ----- play a MMU trick ----- */                      ;\
 279         l.ori   r31,r0,(EXCEPTION_SR)                           ;\
 280         l.mtspr r0,r31,SPR_ESR_BASE                             ;\
 281         /* r31: EA address of handler */                        ;\
 282         LOAD_SYMBOL_2_GPR(r31,handler)                          ;\
 283         l.mtspr r0,r31,SPR_EPCR_BASE                            ;\
 284         l.rfe
 285
 286 /* =====================================================[ exceptions] === */
 287
 288 /* ---[ 0x100: RESET exception ]----------------------------------------- */
 289     .org 0x100
 290         /* Jump to .init code at _start which lives in the .head section
 291          * and will be discarded after boot.
 292          */
 293         LOAD_SYMBOL_2_GPR(r4, _start)
 294         tophys  (r3,r4)                 /* MMU disabled */
 295         l.jr    r3
 296          l.nop
 297
 298 /* ---[ 0x200: BUS exception ]------------------------------------------- */
 299     .org 0x200
 300 _dispatch_bus_fault:
 301         EXCEPTION_HANDLE(_bus_fault_handler)
 302
 303 /* ---[ 0x300: Data Page Fault exception ]------------------------------- */
 304     .org 0x300
 305 _dispatch_do_dpage_fault:
 306 //      totaly disable timer interrupt
 307 //      l.mtspr r0,r0,SPR_TTMR
 308 //      DEBUG_TLB_PROBE(0x300)
 309 //      EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x300)
 310         EXCEPTION_HANDLE(_data_page_fault_handler)
 311
 312 /* ---[ 0x400: Insn Page Fault exception ]------------------------------- */
 313     .org 0x400
 314 _dispatch_do_ipage_fault:
 315 //      totaly disable timer interrupt
 316 //      l.mtspr r0,r0,SPR_TTMR
 317 //      DEBUG_TLB_PROBE(0x400)
 318 //      EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x400)
 319         EXCEPTION_HANDLE(_insn_page_fault_handler)
 320
 321 /* ---[ 0x500: Timer exception ]----------------------------------------- */
 322     .org 0x500
 323         EXCEPTION_HANDLE(_timer_handler)
 324
 325 /* ---[ 0x600: Aligment exception ]-------------------------------------- */
 326     .org 0x600
 327         EXCEPTION_HANDLE(_alignment_handler)
 328
 329 /* ---[ 0x700: Illegal insn exception ]---------------------------------- */
 330     .org 0x700
 331         EXCEPTION_HANDLE(_illegal_instruction_handler)
 332
 333 /* ---[ 0x800: External interrupt exception ]---------------------------- */
 334     .org 0x800
 335         EXCEPTION_HANDLE(_external_irq_handler)
 336
 337 /* ---[ 0x900: DTLB miss exception ]------------------------------------- */
 338     .org 0x900
 339         l.j     boot_dtlb_miss_handler
 340         l.nop
 341
 342 /* ---[ 0xa00: ITLB miss exception ]------------------------------------- */
 343     .org 0xa00
 344         l.j     boot_itlb_miss_handler
 345         l.nop
 346
 347 /* ---[ 0xb00: Range exception ]----------------------------------------- */
 348     .org 0xb00
 349         UNHANDLED_EXCEPTION(_vector_0xb00)
 350
 351 /* ---[ 0xc00: Syscall exception ]--------------------------------------- */
 352     .org 0xc00
 353         EXCEPTION_HANDLE(_sys_call_handler)
 354
 355 /* ---[ 0xd00: Trap exception ]------------------------------------------ */
 356     .org 0xd00
 357         UNHANDLED_EXCEPTION(_vector_0xd00)
 358
 359 /* ---[ 0xe00: Trap exception ]------------------------------------------ */
 360     .org 0xe00
 361 //      UNHANDLED_EXCEPTION(_vector_0xe00)
 362         EXCEPTION_HANDLE(_trap_handler)
 363
 364 /* ---[ 0xf00: Reserved exception ]-------------------------------------- */
 365     .org 0xf00
 366         UNHANDLED_EXCEPTION(_vector_0xf00)
 367
 368 /* ---[ 0x1000: Reserved exception ]------------------------------------- */
 369     .org 0x1000
 370         UNHANDLED_EXCEPTION(_vector_0x1000)
 371
 372 /* ---[ 0x1100: Reserved exception ]------------------------------------- */
 373     .org 0x1100
 374         UNHANDLED_EXCEPTION(_vector_0x1100)
 375
 376 /* ---[ 0x1200: Reserved exception ]------------------------------------- */
 377     .org 0x1200
 378         UNHANDLED_EXCEPTION(_vector_0x1200)
 379
 380 /* ---[ 0x1300: Reserved exception ]------------------------------------- */
 381     .org 0x1300
 382         UNHANDLED_EXCEPTION(_vector_0x1300)
 383
 384 /* ---[ 0x1400: Reserved exception ]------------------------------------- */
 385     .org 0x1400
 386         UNHANDLED_EXCEPTION(_vector_0x1400)
 387
 388 /* ---[ 0x1500: Reserved exception ]------------------------------------- */
 389     .org 0x1500
 390         UNHANDLED_EXCEPTION(_vector_0x1500)
 391
 392 /* ---[ 0x1600: Reserved exception ]------------------------------------- */
 393     .org 0x1600
 394         UNHANDLED_EXCEPTION(_vector_0x1600)
 395
 396 /* ---[ 0x1700: Reserved exception ]------------------------------------- */
 397     .org 0x1700
 398         UNHANDLED_EXCEPTION(_vector_0x1700)
 399
 400 /* ---[ 0x1800: Reserved exception ]------------------------------------- */
 401     .org 0x1800
 402         UNHANDLED_EXCEPTION(_vector_0x1800)
 403
 404 /* ---[ 0x1900: Reserved exception ]------------------------------------- */
 405     .org 0x1900
 406         UNHANDLED_EXCEPTION(_vector_0x1900)
 407
 408 /* ---[ 0x1a00: Reserved exception ]------------------------------------- */
 409     .org 0x1a00
 410         UNHANDLED_EXCEPTION(_vector_0x1a00)
 411
 412 /* ---[ 0x1b00: Reserved exception ]------------------------------------- */
 413     .org 0x1b00
 414         UNHANDLED_EXCEPTION(_vector_0x1b00)
 415
 416 /* ---[ 0x1c00: Reserved exception ]------------------------------------- */
 417     .org 0x1c00
 418         UNHANDLED_EXCEPTION(_vector_0x1c00)
 419
 420 /* ---[ 0x1d00: Reserved exception ]------------------------------------- */
 421     .org 0x1d00
 422         UNHANDLED_EXCEPTION(_vector_0x1d00)
 423
 424 /* ---[ 0x1e00: Reserved exception ]------------------------------------- */
 425     .org 0x1e00
 426         UNHANDLED_EXCEPTION(_vector_0x1e00)
 427
 428 /* ---[ 0x1f00: Reserved exception ]------------------------------------- */
 429     .org 0x1f00
 430         UNHANDLED_EXCEPTION(_vector_0x1f00)
 431
 432     .org 0x2000
 433 /* ===================================================[ kernel start ]=== */
 434
 435 /*    .text*/
 436
 437 /* This early stuff belongs in HEAD, but some of the functions below definitely
 438  * don't... */
 439
 440         __HEAD
 441         .global _start
 442 _start:
 443         /*
 444          * ensure a deterministic start
 445          */
 446
 447         l.ori   r3,r0,0x1
 448         l.mtspr r0,r3,SPR_SR
 449
 450         CLEAR_GPR(r1)
 451         CLEAR_GPR(r2)
 452         CLEAR_GPR(r3)
 453         CLEAR_GPR(r4)
 454         CLEAR_GPR(r5)
 455         CLEAR_GPR(r6)
 456         CLEAR_GPR(r7)
 457         CLEAR_GPR(r8)
 458         CLEAR_GPR(r9)
 459         CLEAR_GPR(r10)
 460         CLEAR_GPR(r11)
 461         CLEAR_GPR(r12)
 462         CLEAR_GPR(r13)
 463         CLEAR_GPR(r14)
 464         CLEAR_GPR(r15)
 465         CLEAR_GPR(r16)
 466         CLEAR_GPR(r17)
 467         CLEAR_GPR(r18)
 468         CLEAR_GPR(r19)
 469         CLEAR_GPR(r20)
 470         CLEAR_GPR(r21)
 471         CLEAR_GPR(r22)
 472         CLEAR_GPR(r23)
 473         CLEAR_GPR(r24)
 474         CLEAR_GPR(r25)
 475         CLEAR_GPR(r26)
 476         CLEAR_GPR(r27)
 477         CLEAR_GPR(r28)
 478         CLEAR_GPR(r29)
 479         CLEAR_GPR(r30)
 480         CLEAR_GPR(r31)
 481
 482         /*
 483          * set up initial ksp and current
 484          */
 485         LOAD_SYMBOL_2_GPR(r1,init_thread_union+0x2000)  // setup kernel stack
 486         LOAD_SYMBOL_2_GPR(r10,init_thread_union)        // setup current
 487         tophys  (r31,r10)
 488         l.sw    TI_KSP(r31), r1
 489
 490         l.ori   r4,r0,0x0
 491
 492
 493         /*
 494          * .data contains initialized data,
 495          * .bss contains uninitialized data - clear it up
 496          */
 497 clear_bss:
 498         LOAD_SYMBOL_2_GPR(r24, __bss_start)
 499         LOAD_SYMBOL_2_GPR(r26, _end)
 500         tophys(r28,r24)
 501         tophys(r30,r26)
 502         CLEAR_GPR(r24)
 503         CLEAR_GPR(r26)
 504 1:
 505         l.sw    (0)(r28),r0
 506         l.sfltu r28,r30
 507         l.bf    1b
 508         l.addi  r28,r28,4
 509
 510 enable_ic:
 511         l.jal   _ic_enable
 512          l.nop
 513
 514 enable_dc:
 515         l.jal   _dc_enable
 516          l.nop
 517
 518 flush_tlb:
 519         /*
 520          *  I N V A L I D A T E   T L B   e n t r i e s
 521          */
 522         LOAD_SYMBOL_2_GPR(r5,SPR_DTLBMR_BASE(0))
 523         LOAD_SYMBOL_2_GPR(r6,SPR_ITLBMR_BASE(0))
 524         l.addi  r7,r0,128 /* Maximum number of sets */
 525 1:
 526         l.mtspr r5,r0,0x0
 527         l.mtspr r6,r0,0x0
 528
 529         l.addi  r5,r5,1
 530         l.addi  r6,r6,1
 531         l.sfeq  r7,r0
 532         l.bnf   1b
 533          l.addi r7,r7,-1
 534
 535
 536 /* The MMU needs to be enabled before or32_early_setup is called */
 537
 538 enable_mmu:
 539         /*
 540          * enable dmmu & immu
 541          * SR[5] = 0, SR[6] = 0, 6th and 7th bit of SR set to 0
 542          */
 543         l.mfspr r30,r0,SPR_SR
 544         l.movhi r28,hi(SPR_SR_DME | SPR_SR_IME)
 545         l.ori   r28,r28,lo(SPR_SR_DME | SPR_SR_IME)
 546         l.or    r30,r30,r28
 547         l.mtspr r0,r30,SPR_SR
 548         l.nop
 549         l.nop
 550         l.nop
 551         l.nop
 552         l.nop
 553         l.nop
 554         l.nop
 555         l.nop
 556         l.nop
 557         l.nop
 558         l.nop
 559         l.nop
 560         l.nop
 561         l.nop
 562         l.nop
 563         l.nop
 564
 565         // reset the simulation counters
 566         l.nop 5
 567
 568         LOAD_SYMBOL_2_GPR(r24, or32_early_setup)
 569         l.jalr r24
 570          l.nop
 571
 572 clear_regs:
 573         /*
 574          * clear all GPRS to increase determinism
 575          */
 576         CLEAR_GPR(r2)
 577         CLEAR_GPR(r3)
 578         CLEAR_GPR(r4)
 579         CLEAR_GPR(r5)
 580         CLEAR_GPR(r6)
 581         CLEAR_GPR(r7)
 582         CLEAR_GPR(r8)
 583         CLEAR_GPR(r9)
 584         CLEAR_GPR(r11)
 585         CLEAR_GPR(r12)
 586         CLEAR_GPR(r13)
 587         CLEAR_GPR(r14)
 588         CLEAR_GPR(r15)
 589         CLEAR_GPR(r16)
 590         CLEAR_GPR(r17)
 591         CLEAR_GPR(r18)
 592         CLEAR_GPR(r19)
 593         CLEAR_GPR(r20)
 594         CLEAR_GPR(r21)
 595         CLEAR_GPR(r22)
 596         CLEAR_GPR(r23)
 597         CLEAR_GPR(r24)
 598         CLEAR_GPR(r25)
 599         CLEAR_GPR(r26)
 600         CLEAR_GPR(r27)
 601         CLEAR_GPR(r28)
 602         CLEAR_GPR(r29)
 603         CLEAR_GPR(r30)
 604         CLEAR_GPR(r31)
 605
 606 jump_start_kernel:
 607         /*
 608          * jump to kernel entry (start_kernel)
 609          */
 610         LOAD_SYMBOL_2_GPR(r30, start_kernel)
 611         l.jr    r30
 612          l.nop
 613
 614 /* ========================================[ cache ]=== */
 615
 616         /* aligment here so we don't change memory offsets with
 617          * memory controler defined
 618          */
 619         .align 0x2000
 620
 621 _ic_enable:
 622         /* Check if IC present and skip enabling otherwise */
 623         l.mfspr r24,r0,SPR_UPR
 624         l.andi  r26,r24,SPR_UPR_ICP
 625         l.sfeq  r26,r0
 626         l.bf    9f
 627         l.nop
 628
 629         /* Disable IC */
 630         l.mfspr r6,r0,SPR_SR
 631         l.addi  r5,r0,-1
 632         l.xori  r5,r5,SPR_SR_ICE
 633         l.and   r5,r6,r5
 634         l.mtspr r0,r5,SPR_SR
 635
 636         /* Establish cache block size
 637            If BS=0, 16;
 638            If BS=1, 32;
 639            r14 contain block size
 640         */
 641         l.mfspr r24,r0,SPR_ICCFGR
 642         l.andi  r26,r24,SPR_ICCFGR_CBS
 643         l.srli  r28,r26,7
 644         l.ori   r30,r0,16
 645         l.sll   r14,r30,r28
 646
 647         /* Establish number of cache sets
 648            r16 contains number of cache sets
 649            r28 contains log(# of cache sets)
 650         */
 651         l.andi  r26,r24,SPR_ICCFGR_NCS
 652         l.srli  r28,r26,3
 653         l.ori   r30,r0,1
 654         l.sll   r16,r30,r28
 655
 656         /* Invalidate IC */
 657         l.addi  r6,r0,0
 658         l.sll   r5,r14,r28
 659 //        l.mul   r5,r14,r16
 660 //      l.trap  1
 661 //      l.addi  r5,r0,IC_SIZE
 662 1:
 663         l.mtspr r0,r6,SPR_ICBIR
 664         l.sfne  r6,r5
 665         l.bf    1b
 666         l.add   r6,r6,r14
 667  //       l.addi   r6,r6,IC_LINE
 668
 669         /* Enable IC */
 670         l.mfspr r6,r0,SPR_SR
 671         l.ori   r6,r6,SPR_SR_ICE
 672         l.mtspr r0,r6,SPR_SR
 673         l.nop
 674         l.nop
 675         l.nop
 676         l.nop
 677         l.nop
 678         l.nop
 679         l.nop
 680         l.nop
 681         l.nop
 682         l.nop
 683 9:
 684         l.jr    r9
 685         l.nop
 686
 687 _dc_enable:
 688         /* Check if DC present and skip enabling otherwise */
 689         l.mfspr r24,r0,SPR_UPR
 690         l.andi  r26,r24,SPR_UPR_DCP
 691         l.sfeq  r26,r0
 692         l.bf    9f
 693         l.nop
 694
 695         /* Disable DC */
 696         l.mfspr r6,r0,SPR_SR
 697         l.addi  r5,r0,-1
 698         l.xori  r5,r5,SPR_SR_DCE
 699         l.and   r5,r6,r5
 700         l.mtspr r0,r5,SPR_SR
 701
 702         /* Establish cache block size
 703            If BS=0, 16;
 704            If BS=1, 32;
 705            r14 contain block size
 706         */
 707         l.mfspr r24,r0,SPR_DCCFGR
 708         l.andi  r26,r24,SPR_DCCFGR_CBS
 709         l.srli  r28,r26,7
 710         l.ori   r30,r0,16
 711         l.sll   r14,r30,r28
 712
 713         /* Establish number of cache sets
 714            r16 contains number of cache sets
 715            r28 contains log(# of cache sets)
 716         */
 717         l.andi  r26,r24,SPR_DCCFGR_NCS
 718         l.srli  r28,r26,3
 719         l.ori   r30,r0,1
 720         l.sll   r16,r30,r28
 721
 722         /* Invalidate DC */
 723         l.addi  r6,r0,0
 724         l.sll   r5,r14,r28
 725 1:
 726         l.mtspr r0,r6,SPR_DCBIR
 727         l.sfne  r6,r5
 728         l.bf    1b
 729         l.add   r6,r6,r14
 730
 731         /* Enable DC */
 732         l.mfspr r6,r0,SPR_SR
 733         l.ori   r6,r6,SPR_SR_DCE
 734         l.mtspr r0,r6,SPR_SR
 735 9:
 736         l.jr    r9
 737         l.nop
 738
 739 /* ===============================================[ page table masks ]=== */
 740
 741 /* bit 4 is used in hardware as write back cache bit. we never use this bit
 742  * explicitly, so we can reuse it as _PAGE_FILE bit and mask it out when
 743  * writing into hardware pte's
 744  */
 745
 746 #define DTLB_UP_CONVERT_MASK  0x3fa
 747 #define ITLB_UP_CONVERT_MASK  0x3a
 748
 749 /* for SMP we'd have (this is a bit subtle, CC must be always set
 750  * for SMP, but since we have _PAGE_PRESENT bit always defined
 751  * we can just modify the mask)
 752  */
 753 #define DTLB_SMP_CONVERT_MASK  0x3fb
 754 #define ITLB_SMP_CONVERT_MASK  0x3b
 755
 756 /* ---[ boot dtlb miss handler ]----------------------------------------- */
 757
 758 boot_dtlb_miss_handler:
 759
 760 /* mask for DTLB_MR register: - (0) sets V (valid) bit,
 761  *                            - (31-12) sets bits belonging to VPN (31-12)
 762  */
 763 #define DTLB_MR_MASK 0xfffff001
 764
 765 /* mask for DTLB_TR register: - (2) sets CI (cache inhibit) bit,
 766  *                            - (4) sets A (access) bit,
 767  *                            - (5) sets D (dirty) bit,
 768  *                            - (8) sets SRE (superuser read) bit
 769  *                            - (9) sets SWE (superuser write) bit
 770  *                            - (31-12) sets bits belonging to VPN (31-12)
 771  */
 772 #define DTLB_TR_MASK 0xfffff332
 773
 774 /* These are for masking out the VPN/PPN value from the MR/TR registers...
 775  * it's not the same as the PFN */
 776 #define VPN_MASK 0xfffff000
 777 #define PPN_MASK 0xfffff000
 778
 779
 780         EXCEPTION_STORE_GPR6
 781
 782 #if 0
 783         l.mfspr r6,r0,SPR_ESR_BASE         //
 784         l.andi  r6,r6,SPR_SR_SM            // are we in kernel mode ?
 785         l.sfeqi r6,0                       // r6 == 0x1 --> SM
 786         l.bf    exit_with_no_dtranslation  //
 787         l.nop
 788 #endif
 789
 790         /* this could be optimized by moving storing of
 791          * non r6 registers here, and jumping r6 restore
 792          * if not in supervisor mode
 793          */
 794
 795         EXCEPTION_STORE_GPR2
 796         EXCEPTION_STORE_GPR3
 797         EXCEPTION_STORE_GPR4
 798         EXCEPTION_STORE_GPR5
 799
 800         l.mfspr r4,r0,SPR_EEAR_BASE        // get the offending EA
 801
 802 immediate_translation:
 803         CLEAR_GPR(r6)
 804
 805         l.srli  r3,r4,0xd                  // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
 806
 807         l.mfspr r6, r0, SPR_DMMUCFGR
 808         l.andi  r6, r6, SPR_DMMUCFGR_NTS
 809         l.srli  r6, r6, SPR_DMMUCFGR_NTS_OFF
 810         l.ori   r5, r0, 0x1
 811         l.sll   r5, r5, r6      // r5 = number DMMU sets
 812         l.addi  r6, r5, -1      // r6 = nsets mask
 813         l.and   r2, r3, r6      // r2 <- r3 % NSETS_MASK
 814
 815         l.or    r6,r6,r4                   // r6 <- r4
 816         l.ori   r6,r6,~(VPN_MASK)          // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
 817         l.movhi r5,hi(DTLB_MR_MASK)        // r5 <- ffff:0000.x000
 818         l.ori   r5,r5,lo(DTLB_MR_MASK)     // r5 <- ffff:1111.x001 - apply DTLB_MR_MASK
 819         l.and   r5,r5,r6                   // r5 <- VPN :VPN .x001 - we have DTLBMR entry
 820         l.mtspr r2,r5,SPR_DTLBMR_BASE(0)   // set DTLBMR
 821
 822         /* set up DTLB with no translation for EA <= 0xbfffffff */
 823         LOAD_SYMBOL_2_GPR(r6,0xbfffffff)
 824         l.sfgeu  r6,r4                     // flag if r6 >= r4 (if 0xbfffffff >= EA)
 825         l.bf     1f                        // goto out
 826         l.and    r3,r4,r4                  // delay slot :: 24 <- r4 (if flag==1)
 827
 828         tophys(r3,r4)                      // r3 <- PA
 829 1:
 830         l.ori   r3,r3,~(PPN_MASK)          // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
 831         l.movhi r5,hi(DTLB_TR_MASK)        // r5 <- ffff:0000.x000
 832         l.ori   r5,r5,lo(DTLB_TR_MASK)     // r5 <- ffff:1111.x330 - apply DTLB_MR_MASK
 833         l.and   r5,r5,r3                   // r5 <- PPN :PPN .x330 - we have DTLBTR entry
 834         l.mtspr r2,r5,SPR_DTLBTR_BASE(0)   // set DTLBTR
 835
 836         EXCEPTION_LOAD_GPR6
 837         EXCEPTION_LOAD_GPR5
 838         EXCEPTION_LOAD_GPR4
 839         EXCEPTION_LOAD_GPR3
 840         EXCEPTION_LOAD_GPR2
 841
 842         l.rfe                              // SR <- ESR, PC <- EPC
 843
 844 exit_with_no_dtranslation:
 845         /* EA out of memory or not in supervisor mode */
 846         EXCEPTION_LOAD_GPR6
 847         EXCEPTION_LOAD_GPR4
 848         l.j     _dispatch_bus_fault
 849
 850 /* ---[ boot itlb miss handler ]----------------------------------------- */
 851
 852 boot_itlb_miss_handler:
 853
 854 /* mask for ITLB_MR register: - sets V (valid) bit,
 855  *                            - sets bits belonging to VPN (15-12)
 856  */
 857 #define ITLB_MR_MASK 0xfffff001
 858
 859 /* mask for ITLB_TR register: - sets A (access) bit,
 860  *                            - sets SXE (superuser execute) bit
 861  *                            - sets bits belonging to VPN (15-12)
 862  */
 863 #define ITLB_TR_MASK 0xfffff050
 864
 865 /*
 866 #define VPN_MASK 0xffffe000
 867 #define PPN_MASK 0xffffe000
 868 */
 869
 870
 871
 872         EXCEPTION_STORE_GPR2
 873         EXCEPTION_STORE_GPR3
 874         EXCEPTION_STORE_GPR4
 875         EXCEPTION_STORE_GPR5
 876         EXCEPTION_STORE_GPR6
 877
 878 #if 0
 879         l.mfspr r6,r0,SPR_ESR_BASE         //
 880         l.andi  r6,r6,SPR_SR_SM            // are we in kernel mode ?
 881         l.sfeqi r6,0                       // r6 == 0x1 --> SM
 882         l.bf    exit_with_no_itranslation
 883         l.nop
 884 #endif
 885
 886
 887         l.mfspr r4,r0,SPR_EEAR_BASE        // get the offending EA
 888
 889 earlyearly:
 890         CLEAR_GPR(r6)
 891
 892         l.srli  r3,r4,0xd                  // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
 893
 894         l.mfspr r6, r0, SPR_IMMUCFGR
 895         l.andi  r6, r6, SPR_IMMUCFGR_NTS
 896         l.srli  r6, r6, SPR_IMMUCFGR_NTS_OFF
 897         l.ori   r5, r0, 0x1
 898         l.sll   r5, r5, r6      // r5 = number IMMU sets from IMMUCFGR
 899         l.addi  r6, r5, -1      // r6 = nsets mask
 900         l.and   r2, r3, r6      // r2 <- r3 % NSETS_MASK
 901
 902         l.or    r6,r6,r4                   // r6 <- r4
 903         l.ori   r6,r6,~(VPN_MASK)          // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
 904         l.movhi r5,hi(ITLB_MR_MASK)        // r5 <- ffff:0000.x000
 905         l.ori   r5,r5,lo(ITLB_MR_MASK)     // r5 <- ffff:1111.x001 - apply ITLB_MR_MASK
 906         l.and   r5,r5,r6                   // r5 <- VPN :VPN .x001 - we have ITLBMR entry
 907         l.mtspr r2,r5,SPR_ITLBMR_BASE(0)   // set ITLBMR
 908
 909         /*
 910          * set up ITLB with no translation for EA <= 0x0fffffff
 911          *
 912          * we need this for head.S mapping (EA = PA). if we move all functions
 913          * which run with mmu enabled into entry.S, we might be able to eliminate this.
 914          *
 915          */
 916         LOAD_SYMBOL_2_GPR(r6,0x0fffffff)
 917         l.sfgeu  r6,r4                     // flag if r6 >= r4 (if 0xb0ffffff >= EA)
 918         l.bf     1f                        // goto out
 919         l.and    r3,r4,r4                  // delay slot :: 24 <- r4 (if flag==1)
 920
 921         tophys(r3,r4)                      // r3 <- PA
 922 1:
 923         l.ori   r3,r3,~(PPN_MASK)          // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
 924         l.movhi r5,hi(ITLB_TR_MASK)        // r5 <- ffff:0000.x000
 925         l.ori   r5,r5,lo(ITLB_TR_MASK)     // r5 <- ffff:1111.x050 - apply ITLB_MR_MASK
 926         l.and   r5,r5,r3                   // r5 <- PPN :PPN .x050 - we have ITLBTR entry
 927         l.mtspr r2,r5,SPR_ITLBTR_BASE(0)   // set ITLBTR
 928
 929         EXCEPTION_LOAD_GPR6
 930         EXCEPTION_LOAD_GPR5
 931         EXCEPTION_LOAD_GPR4
 932         EXCEPTION_LOAD_GPR3
 933         EXCEPTION_LOAD_GPR2
 934
 935         l.rfe                              // SR <- ESR, PC <- EPC
 936
 937 exit_with_no_itranslation:
 938         EXCEPTION_LOAD_GPR4
 939         EXCEPTION_LOAD_GPR6
 940         l.j    _dispatch_bus_fault
 941         l.nop
 942
 943 /* ====================================================================== */
 944 /*
 945  * Stuff below here shouldn't go into .head section... maybe this stuff
 946  * can be moved to entry.S ???
 947  */
 948
 949 /* ==============================================[ DTLB miss handler ]=== */
 950
 951 /*
 952  * Comments:
 953  *   Exception handlers are entered with MMU off so the following handler
 954  *   needs to use physical addressing
 955  *
 956  */
 957
 958         .text
 959 ENTRY(dtlb_miss_handler)
 960         EXCEPTION_STORE_GPR2
 961         EXCEPTION_STORE_GPR3
 962         EXCEPTION_STORE_GPR4
 963         EXCEPTION_STORE_GPR5
 964         EXCEPTION_STORE_GPR6
 965         /*
 966          * get EA of the miss
 967          */
 968         l.mfspr r2,r0,SPR_EEAR_BASE
 969         /*
 970          * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
 971          */
 972         GET_CURRENT_PGD(r3,r5)          // r3 is current_pgd, r5 is temp
 973         l.srli  r4,r2,0x18              // >> PAGE_SHIFT + (PAGE_SHIFT - 2)
 974         l.slli  r4,r4,0x2               // to get address << 2
 975         l.add   r5,r4,r3                // r4 is pgd_index(daddr)
 976         /*
 977          * if (pmd_none(*pmd))
 978          *   goto pmd_none:
 979          */
 980         tophys  (r4,r5)
 981         l.lwz   r3,0x0(r4)              // get *pmd value
 982         l.sfne  r3,r0
 983         l.bnf   d_pmd_none
 984          l.andi r3,r3,~PAGE_MASK //0x1fff               // ~PAGE_MASK
 985         /*
 986          * if (pmd_bad(*pmd))
 987          *   pmd_clear(pmd)
 988          *   goto pmd_bad:
 989          */
 990 //      l.sfeq  r3,r0                   // check *pmd value
 991 //      l.bf    d_pmd_good
 992         l.addi  r3,r0,0xffffe000        // PAGE_MASK
 993 //      l.j     d_pmd_bad
 994 //      l.sw    0x0(r4),r0              // clear pmd
 995 d_pmd_good:
 996         /*
 997          * pte = *pte_offset(pmd, daddr);
 998          */
 999         l.lwz   r4,0x0(r4)              // get **pmd value
1000         l.and   r4,r4,r3                // & PAGE_MASK
1001         l.srli  r5,r2,0xd               // >> PAGE_SHIFT, r2 == EEAR
1002         l.andi  r3,r5,0x7ff             // (1UL << PAGE_SHIFT - 2) - 1
1003         l.slli  r3,r3,0x2               // to get address << 2
1004         l.add   r3,r3,r4
1005         l.lwz   r2,0x0(r3)              // this is pte at last
1006         /*
1007          * if (!pte_present(pte))
1008          */
1009         l.andi  r4,r2,0x1
1010         l.sfne  r4,r0                   // is pte present
1011         l.bnf   d_pte_not_present
1012         l.addi  r3,r0,0xffffe3fa        // PAGE_MASK | DTLB_UP_CONVERT_MASK
1013         /*
1014          * fill DTLB TR register
1015          */
1016         l.and   r4,r2,r3                // apply the mask
1017         // Determine number of DMMU sets
1018         l.mfspr r6, r0, SPR_DMMUCFGR
1019         l.andi  r6, r6, SPR_DMMUCFGR_NTS
1020         l.srli  r6, r6, SPR_DMMUCFGR_NTS_OFF
1021         l.ori   r3, r0, 0x1
1022         l.sll   r3, r3, r6      // r3 = number DMMU sets DMMUCFGR
1023         l.addi  r6, r3, -1      // r6 = nsets mask
1024         l.and   r5, r5, r6      // calc offset:  & (NUM_TLB_ENTRIES-1)
1025                                                            //NUM_TLB_ENTRIES
1026         l.mtspr r5,r4,SPR_DTLBTR_BASE(0)
1027         /*
1028          * fill DTLB MR register
1029          */
1030         l.mfspr r2,r0,SPR_EEAR_BASE
1031         l.addi  r3,r0,0xffffe000        // PAGE_MASK
1032         l.and   r4,r2,r3                // apply PAGE_MASK to EA (__PHX__ do we really need this?)
1033         l.ori   r4,r4,0x1               // set hardware valid bit: DTBL_MR entry
1034         l.mtspr r5,r4,SPR_DTLBMR_BASE(0)
1035
1036         EXCEPTION_LOAD_GPR2
1037         EXCEPTION_LOAD_GPR3
1038         EXCEPTION_LOAD_GPR4
1039         EXCEPTION_LOAD_GPR5
1040         EXCEPTION_LOAD_GPR6
1041         l.rfe
1042 d_pmd_bad:
1043         l.nop   1
1044         EXCEPTION_LOAD_GPR2
1045         EXCEPTION_LOAD_GPR3
1046         EXCEPTION_LOAD_GPR4
1047         EXCEPTION_LOAD_GPR5
1048         EXCEPTION_LOAD_GPR6
1049         l.rfe
1050 d_pmd_none:
1051 d_pte_not_present:
1052         EXCEPTION_LOAD_GPR2
1053         EXCEPTION_LOAD_GPR3
1054         EXCEPTION_LOAD_GPR4
1055         EXCEPTION_LOAD_GPR5
1056         EXCEPTION_LOAD_GPR6
1057         l.j     _dispatch_do_dpage_fault
1058         l.nop
1059
1060 /* ==============================================[ ITLB miss handler ]=== */
1061 ENTRY(itlb_miss_handler)
1062         EXCEPTION_STORE_GPR2
1063         EXCEPTION_STORE_GPR3
1064         EXCEPTION_STORE_GPR4
1065         EXCEPTION_STORE_GPR5
1066         EXCEPTION_STORE_GPR6
1067         /*
1068          * get EA of the miss
1069          */
1070         l.mfspr r2,r0,SPR_EEAR_BASE
1071
1072         /*
1073          * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
1074          *
1075          */
1076         GET_CURRENT_PGD(r3,r5)          // r3 is current_pgd, r5 is temp
1077         l.srli  r4,r2,0x18              // >> PAGE_SHIFT + (PAGE_SHIFT - 2)
1078         l.slli  r4,r4,0x2               // to get address << 2
1079         l.add   r5,r4,r3                // r4 is pgd_index(daddr)
1080         /*
1081          * if (pmd_none(*pmd))
1082          *   goto pmd_none:
1083          */
1084         tophys  (r4,r5)
1085         l.lwz   r3,0x0(r4)              // get *pmd value
1086         l.sfne  r3,r0
1087         l.bnf   i_pmd_none
1088         l.andi  r3,r3,0x1fff            // ~PAGE_MASK
1089         /*
1090          * if (pmd_bad(*pmd))
1091          *   pmd_clear(pmd)
1092          *   goto pmd_bad:
1093          */
1094
1095 //      l.sfeq  r3,r0                   // check *pmd value
1096 //      l.bf    i_pmd_good
1097         l.addi  r3,r0,0xffffe000        // PAGE_MASK
1098 //      l.j     i_pmd_bad
1099 //      l.sw    0x0(r4),r0              // clear pmd
1100
1101 i_pmd_good:
1102         /*
1103          * pte = *pte_offset(pmd, iaddr);
1104          *
1105          */
1106         l.lwz   r4,0x0(r4)              // get **pmd value
1107         l.and   r4,r4,r3                // & PAGE_MASK
1108         l.srli  r5,r2,0xd               // >> PAGE_SHIFT, r2 == EEAR
1109         l.andi  r3,r5,0x7ff             // (1UL << PAGE_SHIFT - 2) - 1
1110         l.slli  r3,r3,0x2               // to get address << 2
1111         l.add   r3,r3,r4
1112         l.lwz   r2,0x0(r3)              // this is pte at last
1113         /*
1114          * if (!pte_present(pte))
1115          *
1116          */
1117         l.andi  r4,r2,0x1
1118         l.sfne  r4,r0                   // is pte present
1119         l.bnf   i_pte_not_present
1120         l.addi  r3,r0,0xffffe03a        // PAGE_MASK | ITLB_UP_CONVERT_MASK
1121         /*
1122          * fill ITLB TR register
1123          */
1124         l.and   r4,r2,r3                // apply the mask
1125         l.andi  r3,r2,0x7c0             // _PAGE_EXEC | _PAGE_SRE | _PAGE_SWE |  _PAGE_URE | _PAGE_UWE
1126 //      l.andi  r3,r2,0x400             // _PAGE_EXEC
1127         l.sfeq  r3,r0
1128         l.bf    itlb_tr_fill //_workaround
1129         // Determine number of IMMU sets
1130         l.mfspr r6, r0, SPR_IMMUCFGR
1131         l.andi  r6, r6, SPR_IMMUCFGR_NTS
1132         l.srli  r6, r6, SPR_IMMUCFGR_NTS_OFF
1133         l.ori   r3, r0, 0x1
1134         l.sll   r3, r3, r6      // r3 = number IMMU sets IMMUCFGR
1135         l.addi  r6, r3, -1      // r6 = nsets mask
1136         l.and   r5, r5, r6      // calc offset:  & (NUM_TLB_ENTRIES-1)
1137
1138 /*
1139  * __PHX__ :: fixme
1140  * we should not just blindly set executable flags,
1141  * but it does help with ping. the clean way would be to find out
1142  * (and fix it) why stack doesn't have execution permissions
1143  */
1144
1145 itlb_tr_fill_workaround:
1146         l.ori   r4,r4,0xc0              // | (SPR_ITLBTR_UXE | ITLBTR_SXE)
1147 itlb_tr_fill:
1148         l.mtspr r5,r4,SPR_ITLBTR_BASE(0)
1149         /*
1150          * fill DTLB MR register
1151          */
1152         l.mfspr r2,r0,SPR_EEAR_BASE
1153         l.addi  r3,r0,0xffffe000        // PAGE_MASK
1154         l.and   r4,r2,r3                // apply PAGE_MASK to EA (__PHX__ do we really need this?)
1155         l.ori   r4,r4,0x1               // set hardware valid bit: DTBL_MR entry
1156         l.mtspr r5,r4,SPR_ITLBMR_BASE(0)
1157
1158         EXCEPTION_LOAD_GPR2
1159         EXCEPTION_LOAD_GPR3
1160         EXCEPTION_LOAD_GPR4
1161         EXCEPTION_LOAD_GPR5
1162         EXCEPTION_LOAD_GPR6
1163         l.rfe
1164
1165 i_pmd_bad:
1166         l.nop   1
1167         EXCEPTION_LOAD_GPR2
1168         EXCEPTION_LOAD_GPR3
1169         EXCEPTION_LOAD_GPR4
1170         EXCEPTION_LOAD_GPR5
1171         EXCEPTION_LOAD_GPR6
1172         l.rfe
1173 i_pmd_none:
1174 i_pte_not_present:
1175         EXCEPTION_LOAD_GPR2
1176         EXCEPTION_LOAD_GPR3
1177         EXCEPTION_LOAD_GPR4
1178         EXCEPTION_LOAD_GPR5
1179         EXCEPTION_LOAD_GPR6
1180         l.j     _dispatch_do_ipage_fault
1181         l.nop
1182
1183 /* ==============================================[ boot tlb handlers ]=== */
1184
1185
1186 /* =================================================[ debugging aids ]=== */
1187
1188         .align 64
1189 _immu_trampoline:
1190         .space 64
1191 _immu_trampoline_top:
1192
1193 #define TRAMP_SLOT_0            (0x0)
1194 #define TRAMP_SLOT_1            (0x4)
1195 #define TRAMP_SLOT_2            (0x8)
1196 #define TRAMP_SLOT_3            (0xc)
1197 #define TRAMP_SLOT_4            (0x10)
1198 #define TRAMP_SLOT_5            (0x14)
1199 #define TRAMP_FRAME_SIZE        (0x18)
1200
1201 ENTRY(_immu_trampoline_workaround)
1202         // r2 EEA
1203         // r6 is physical EEA
1204         tophys(r6,r2)
1205
1206         LOAD_SYMBOL_2_GPR(r5,_immu_trampoline)
1207         tophys  (r3,r5)                 // r3 is trampoline (physical)
1208
1209         LOAD_SYMBOL_2_GPR(r4,0x15000000)
1210         l.sw    TRAMP_SLOT_0(r3),r4
1211         l.sw    TRAMP_SLOT_1(r3),r4
1212         l.sw    TRAMP_SLOT_4(r3),r4
1213         l.sw    TRAMP_SLOT_5(r3),r4
1214
1215                                         // EPC = EEA - 0x4
1216         l.lwz   r4,0x0(r6)              // load op @ EEA + 0x0 (fc address)
1217         l.sw    TRAMP_SLOT_3(r3),r4     // store it to _immu_trampoline_data
1218         l.lwz   r4,-0x4(r6)             // load op @ EEA - 0x4 (f8 address)
1219         l.sw    TRAMP_SLOT_2(r3),r4     // store it to _immu_trampoline_data
1220
1221         l.srli  r5,r4,26                // check opcode for write access
1222         l.sfeqi r5,0                    // l.j
1223         l.bf    0f
1224         l.sfeqi r5,0x11                 // l.jr
1225         l.bf    1f
1226         l.sfeqi r5,1                    // l.jal
1227         l.bf    2f
1228         l.sfeqi r5,0x12                 // l.jalr
1229         l.bf    3f
1230         l.sfeqi r5,3                    // l.bnf
1231         l.bf    4f
1232         l.sfeqi r5,4                    // l.bf
1233         l.bf    5f
1234 99:
1235         l.nop
1236         l.j     99b                     // should never happen
1237         l.nop   1
1238
1239         // r2 is EEA
1240         // r3 is trampoline address (physical)
1241         // r4 is instruction
1242         // r6 is physical(EEA)
1243         //
1244         // r5
1245
1246 2:      // l.jal
1247
1248         /* 19 20 aa aa  l.movhi r9,0xaaaa
1249          * a9 29 bb bb  l.ori   r9,0xbbbb
1250          *
1251          * where 0xaaaabbbb is EEA + 0x4 shifted right 2
1252          */
1253
1254         l.addi  r6,r2,0x4               // this is 0xaaaabbbb
1255
1256                                         // l.movhi r9,0xaaaa
1257         l.ori   r5,r0,0x1920            // 0x1920 == l.movhi r9
1258         l.sh    (TRAMP_SLOT_0+0x0)(r3),r5
1259         l.srli  r5,r6,16
1260         l.sh    (TRAMP_SLOT_0+0x2)(r3),r5
1261
1262                                         // l.ori   r9,0xbbbb
1263         l.ori   r5,r0,0xa929            // 0xa929 == l.ori r9
1264         l.sh    (TRAMP_SLOT_1+0x0)(r3),r5
1265         l.andi  r5,r6,0xffff
1266         l.sh    (TRAMP_SLOT_1+0x2)(r3),r5
1267
1268         /* falthrough, need to set up new jump offset */
1269
1270
1271 0:      // l.j
1272         l.slli  r6,r4,6                 // original offset shifted left 6 - 2
1273 //      l.srli  r6,r6,6                 // original offset shifted right 2
1274
1275         l.slli  r4,r2,4                 // old jump position: EEA shifted left 4
1276 //      l.srli  r4,r4,6                 // old jump position: shifted right 2
1277
1278         l.addi  r5,r3,0xc               // new jump position (physical)
1279         l.slli  r5,r5,4                 // new jump position: shifted left 4
1280
1281         // calculate new jump offset
1282         // new_off = old_off + (old_jump - new_jump)
1283
1284         l.sub   r5,r4,r5                // old_jump - new_jump
1285         l.add   r5,r6,r5                // orig_off + (old_jump - new_jump)
1286         l.srli  r5,r5,6                 // new offset shifted right 2
1287
1288         // r5 is new jump offset
1289                                         // l.j has opcode 0x0...
1290         l.sw    TRAMP_SLOT_2(r3),r5     // write it back
1291
1292         l.j     trampoline_out
1293         l.nop
1294
1295 /* ----------------------------- */
1296
1297 3:      // l.jalr
1298
1299         /* 19 20 aa aa  l.movhi r9,0xaaaa
1300          * a9 29 bb bb  l.ori   r9,0xbbbb
1301          *
1302          * where 0xaaaabbbb is EEA + 0x4 shifted right 2
1303          */
1304
1305         l.addi  r6,r2,0x4               // this is 0xaaaabbbb
1306
1307                                         // l.movhi r9,0xaaaa
1308         l.ori   r5,r0,0x1920            // 0x1920 == l.movhi r9
1309         l.sh    (TRAMP_SLOT_0+0x0)(r3),r5
1310         l.srli  r5,r6,16
1311         l.sh    (TRAMP_SLOT_0+0x2)(r3),r5
1312
1313                                         // l.ori   r9,0xbbbb
1314         l.ori   r5,r0,0xa929            // 0xa929 == l.ori r9
1315         l.sh    (TRAMP_SLOT_1+0x0)(r3),r5
1316         l.andi  r5,r6,0xffff
1317         l.sh    (TRAMP_SLOT_1+0x2)(r3),r5
1318
1319         l.lhz   r5,(TRAMP_SLOT_2+0x0)(r3)       // load hi part of jump instruction
1320         l.andi  r5,r5,0x3ff             // clear out opcode part
1321         l.ori   r5,r5,0x4400            // opcode changed from l.jalr -> l.jr
1322         l.sh    (TRAMP_SLOT_2+0x0)(r3),r5 // write it back
1323
1324         /* falthrough */
1325
1326 1:      // l.jr
1327         l.j     trampoline_out
1328         l.nop
1329
1330 /* ----------------------------- */
1331
1332 4:      // l.bnf
1333 5:      // l.bf
1334         l.slli  r6,r4,6                 // original offset shifted left 6 - 2
1335 //      l.srli  r6,r6,6                 // original offset shifted right 2
1336
1337         l.slli  r4,r2,4                 // old jump position: EEA shifted left 4
1338 //      l.srli  r4,r4,6                 // old jump position: shifted right 2
1339
1340         l.addi  r5,r3,0xc               // new jump position (physical)
1341         l.slli  r5,r5,4                 // new jump position: shifted left 4
1342
1343         // calculate new jump offset
1344         // new_off = old_off + (old_jump - new_jump)
1345
1346         l.add   r6,r6,r4                // (orig_off + old_jump)
1347         l.sub   r6,r6,r5                // (orig_off + old_jump) - new_jump
1348         l.srli  r6,r6,6                 // new offset shifted right 2
1349
1350         // r6 is new jump offset
1351         l.lwz   r4,(TRAMP_SLOT_2+0x0)(r3)       // load jump instruction
1352         l.srli  r4,r4,16
1353         l.andi  r4,r4,0xfc00            // get opcode part
1354         l.slli  r4,r4,16
1355         l.or    r6,r4,r6                // l.b(n)f new offset
1356         l.sw    TRAMP_SLOT_2(r3),r6     // write it back
1357
1358         /* we need to add l.j to EEA + 0x8 */
1359         tophys  (r4,r2)                 // may not be needed (due to shifts down_
1360         l.addi  r4,r4,(0x8 - 0x8)       // jump target = r2 + 0x8 (compensate for 0x8)
1361                                         // jump position = r5 + 0x8 (0x8 compensated)
1362         l.sub   r4,r4,r5                // jump offset = target - new_position + 0x8
1363
1364         l.slli  r4,r4,4                 // the amount of info in imediate of jump
1365         l.srli  r4,r4,6                 // jump instruction with offset
1366         l.sw    TRAMP_SLOT_4(r3),r4     // write it to 4th slot
1367
1368         /* fallthrough */
1369
1370 trampoline_out:
1371         // set up new EPC to point to our trampoline code
1372         LOAD_SYMBOL_2_GPR(r5,_immu_trampoline)
1373         l.mtspr r0,r5,SPR_EPCR_BASE
1374
1375         // immu_trampoline is (4x) CACHE_LINE aligned
1376         // and only 6 instructions long,
1377         // so we need to invalidate only 2 lines
1378
1379         /* Establish cache block size
1380            If BS=0, 16;
1381            If BS=1, 32;
1382            r14 contain block size
1383         */
1384         l.mfspr r21,r0,SPR_ICCFGR
1385         l.andi  r21,r21,SPR_ICCFGR_CBS
1386         l.srli  r21,r21,7
1387         l.ori   r23,r0,16
1388         l.sll   r14,r23,r21
1389
1390         l.mtspr r0,r5,SPR_ICBIR
1391         l.add   r5,r5,r14
1392         l.mtspr r0,r5,SPR_ICBIR
1393
1394         l.jr    r9
1395         l.nop
1396
1397
1398 /*
1399  * DSCR: prints a string referenced by r3.
1400  *
1401  * PRMS: r3             - address of the first character of null
1402  *                      terminated string to be printed
1403  *
1404  * PREQ: UART at UART_BASE_ADD has to be initialized
1405  *
1406  * POST: caller should be aware that r3, r9 are changed
1407  */
1408 ENTRY(_emergency_print)
1409         EMERGENCY_PRINT_STORE_GPR4
1410         EMERGENCY_PRINT_STORE_GPR5
1411         EMERGENCY_PRINT_STORE_GPR6
1412         EMERGENCY_PRINT_STORE_GPR7
1413 2:
1414         l.lbz   r7,0(r3)
1415         l.sfeq  r7,r0
1416         l.bf    9f
1417         l.nop
1418
1419 // putc:
1420         l.movhi r4,hi(UART_BASE_ADD)
1421
1422         l.addi  r6,r0,0x20
1423 1:      l.lbz   r5,5(r4)
1424         l.andi  r5,r5,0x20
1425         l.sfeq  r5,r6
1426         l.bnf   1b
1427         l.nop
1428
1429         l.sb    0(r4),r7
1430
1431         l.addi  r6,r0,0x60
1432 1:      l.lbz   r5,5(r4)
1433         l.andi  r5,r5,0x60
1434         l.sfeq  r5,r6
1435         l.bnf   1b
1436         l.nop
1437
1438         /* next character */
1439         l.j     2b
1440         l.addi  r3,r3,0x1
1441
1442 9:
1443         EMERGENCY_PRINT_LOAD_GPR7
1444         EMERGENCY_PRINT_LOAD_GPR6
1445         EMERGENCY_PRINT_LOAD_GPR5
1446         EMERGENCY_PRINT_LOAD_GPR4
1447         l.jr    r9
1448         l.nop
1449
1450 ENTRY(_emergency_print_nr)
1451         EMERGENCY_PRINT_STORE_GPR4
1452         EMERGENCY_PRINT_STORE_GPR5
1453         EMERGENCY_PRINT_STORE_GPR6
1454         EMERGENCY_PRINT_STORE_GPR7
1455         EMERGENCY_PRINT_STORE_GPR8
1456
1457         l.addi  r8,r0,32                // shift register
1458
1459 1:      /* remove leading zeros */
1460         l.addi  r8,r8,-0x4
1461         l.srl   r7,r3,r8
1462         l.andi  r7,r7,0xf
1463
1464         /* don't skip the last zero if number == 0x0 */
1465         l.sfeqi r8,0x4
1466         l.bf    2f
1467         l.nop
1468
1469         l.sfeq  r7,r0
1470         l.bf    1b
1471         l.nop
1472
1473 2:
1474         l.srl   r7,r3,r8
1475
1476         l.andi  r7,r7,0xf
1477         l.sflts r8,r0
1478         l.bf    9f
1479
1480         l.sfgtui r7,0x9
1481         l.bnf   8f
1482         l.nop
1483         l.addi  r7,r7,0x27
1484
1485 8:
1486         l.addi  r7,r7,0x30
1487 // putc:
1488         l.movhi r4,hi(UART_BASE_ADD)
1489
1490         l.addi  r6,r0,0x20
1491 1:      l.lbz   r5,5(r4)
1492         l.andi  r5,r5,0x20
1493         l.sfeq  r5,r6
1494         l.bnf   1b
1495         l.nop
1496
1497         l.sb    0(r4),r7
1498
1499         l.addi  r6,r0,0x60
1500 1:      l.lbz   r5,5(r4)
1501         l.andi  r5,r5,0x60
1502         l.sfeq  r5,r6
1503         l.bnf   1b
1504         l.nop
1505
1506         /* next character */
1507         l.j     2b
1508         l.addi  r8,r8,-0x4
1509
1510 9:
1511         EMERGENCY_PRINT_LOAD_GPR8
1512         EMERGENCY_PRINT_LOAD_GPR7
1513         EMERGENCY_PRINT_LOAD_GPR6
1514         EMERGENCY_PRINT_LOAD_GPR5
1515         EMERGENCY_PRINT_LOAD_GPR4
1516         l.jr    r9
1517         l.nop
1518
1519
1520 /*
1521  * This should be used for debugging only.
1522  * It messes up the Linux early serial output
1523  * somehow, so use it sparingly and essentially
1524  * only if you need to debug something that goes wrong
1525  * before Linux gets the early serial going.
1526  *
1527  * Furthermore, you'll have to make sure you set the
1528  * UART_DEVISOR correctly according to the system
1529  * clock rate.
1530  *
1531  *
1532  */
1533
1534
1535
1536 #define SYS_CLK            20000000
1537 //#define SYS_CLK            1843200
1538 #define OR32_CONSOLE_BAUD  115200
1539 #define UART_DIVISOR       SYS_CLK/(16*OR32_CONSOLE_BAUD)
1540
1541 ENTRY(_early_uart_init)
1542         l.movhi r3,hi(UART_BASE_ADD)
1543
1544         l.addi  r4,r0,0x7
1545         l.sb    0x2(r3),r4
1546
1547         l.addi  r4,r0,0x0
1548         l.sb    0x1(r3),r4
1549
1550         l.addi  r4,r0,0x3
1551         l.sb    0x3(r3),r4
1552
1553         l.lbz   r5,3(r3)
1554         l.ori   r4,r5,0x80
1555         l.sb    0x3(r3),r4
1556         l.addi  r4,r0,((UART_DIVISOR>>8) & 0x000000ff)
1557         l.sb    UART_DLM(r3),r4
1558         l.addi  r4,r0,((UART_DIVISOR) & 0x000000ff)
1559         l.sb    UART_DLL(r3),r4
1560         l.sb    0x3(r3),r5
1561
1562         l.jr    r9
1563         l.nop
1564
1565 _string_copying_linux:
1566         .string "\n\n\n\n\n\rCopying Linux... \0"
1567
1568 _string_ok_booting:
1569         .string "Ok, booting the kernel.\n\r\0"
1570
1571 _string_unhandled_exception:
1572         .string "\n\rRunarunaround: Unhandled exception 0x\0"
1573
1574 _string_epc_prefix:
1575         .string ": EPC=0x\0"
1576
1577 _string_nl:
1578         .string "\n\r\0"
1579
1580         .global _string_esr_irq_bug
1581 _string_esr_irq_bug:
1582         .string "\n\rESR external interrupt bug, for details look into entry.S\n\r\0"
1583
1584
1585
1586 /* ========================================[ page aligned structures ]=== */
1587
1588 /*
1589  * .data section should be page aligned
1590  *      (look into arch/or32/kernel/vmlinux.lds)
1591  */
1592         .section .data,"aw"
1593         .align  8192
1594         .global  empty_zero_page
1595 empty_zero_page:
1596         .space  8192
1597
1598         .global  swapper_pg_dir
1599 swapper_pg_dir:
1600         .space  8192
1601
1602         .global _unhandled_stack
1603 _unhandled_stack:
1604         .space  8192
1605 _unhandled_stack_top:
1606
1607 /* ============================================================[ EOF ]=== */