LXR linux/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 <linux/serial_reg.h>
  23#include <asm/processor.h>
  24#include <asm/page.h>
  25#include <asm/mmu.h>
  26#include <asm/pgtable.h>
  27#include <asm/cache.h>
  28#include <asm/spr_defs.h>
  29#include <asm/asm-offsets.h>
  30#include <linux/of_fdt.h>
  31
  32#define tophys(rd,rs)                           \
  33        l.movhi rd,hi(-KERNELBASE)              ;\
  34        l.add   rd,rd,rs
  35
  36#define CLEAR_GPR(gpr)                          \
  37        l.or    gpr,r0,r0
  38
  39#define LOAD_SYMBOL_2_GPR(gpr,symbol)           \
  40        l.movhi gpr,hi(symbol)                  ;\
  41        l.ori   gpr,gpr,lo(symbol)
  42
  43
  44#define UART_BASE_ADD      0x90000000
  45
  46#define EXCEPTION_SR  (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_SM)
  47#define SYSCALL_SR  (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_IEE | SPR_SR_TEE | SPR_SR_SM)
  48
  49/* ============================================[ tmp store locations ]=== */
  50
  51/*
  52 * emergency_print temporary stores
  53 */
  54#define EMERGENCY_PRINT_STORE_GPR4      l.sw    0x20(r0),r4
  55#define EMERGENCY_PRINT_LOAD_GPR4       l.lwz   r4,0x20(r0)
  56
  57#define EMERGENCY_PRINT_STORE_GPR5      l.sw    0x24(r0),r5
  58#define EMERGENCY_PRINT_LOAD_GPR5       l.lwz   r5,0x24(r0)
  59
  60#define EMERGENCY_PRINT_STORE_GPR6      l.sw    0x28(r0),r6
  61#define EMERGENCY_PRINT_LOAD_GPR6       l.lwz   r6,0x28(r0)
  62
  63#define EMERGENCY_PRINT_STORE_GPR7      l.sw    0x2c(r0),r7
  64#define EMERGENCY_PRINT_LOAD_GPR7       l.lwz   r7,0x2c(r0)
  65
  66#define EMERGENCY_PRINT_STORE_GPR8      l.sw    0x30(r0),r8
  67#define EMERGENCY_PRINT_LOAD_GPR8       l.lwz   r8,0x30(r0)
  68
  69#define EMERGENCY_PRINT_STORE_GPR9      l.sw    0x34(r0),r9
  70#define EMERGENCY_PRINT_LOAD_GPR9       l.lwz   r9,0x34(r0)
  71
  72
  73/*
  74 * TLB miss handlers temorary stores
  75 */
  76#define EXCEPTION_STORE_GPR9            l.sw    0x10(r0),r9
  77#define EXCEPTION_LOAD_GPR9             l.lwz   r9,0x10(r0)
  78
  79#define EXCEPTION_STORE_GPR2            l.sw    0x64(r0),r2
  80#define EXCEPTION_LOAD_GPR2             l.lwz   r2,0x64(r0)
  81
  82#define EXCEPTION_STORE_GPR3            l.sw    0x68(r0),r3
  83#define EXCEPTION_LOAD_GPR3             l.lwz   r3,0x68(r0)
  84
  85#define EXCEPTION_STORE_GPR4            l.sw    0x6c(r0),r4
  86#define EXCEPTION_LOAD_GPR4             l.lwz   r4,0x6c(r0)
  87
  88#define EXCEPTION_STORE_GPR5            l.sw    0x70(r0),r5
  89#define EXCEPTION_LOAD_GPR5             l.lwz   r5,0x70(r0)
  90
  91#define EXCEPTION_STORE_GPR6            l.sw    0x74(r0),r6
  92#define EXCEPTION_LOAD_GPR6             l.lwz   r6,0x74(r0)
  93
  94
  95/*
  96 * EXCEPTION_HANDLE temporary stores
  97 */
  98
  99#define EXCEPTION_T_STORE_GPR30         l.sw    0x78(r0),r30
 100#define EXCEPTION_T_LOAD_GPR30(reg)     l.lwz   reg,0x78(r0)
 101
 102#define EXCEPTION_T_STORE_GPR10         l.sw    0x7c(r0),r10
 103#define EXCEPTION_T_LOAD_GPR10(reg)     l.lwz   reg,0x7c(r0)
 104
 105#define EXCEPTION_T_STORE_SP            l.sw    0x80(r0),r1
 106#define EXCEPTION_T_LOAD_SP(reg)        l.lwz   reg,0x80(r0)
 107
 108/*
 109 * For UNHANLDED_EXCEPTION
 110 */
 111
 112#define EXCEPTION_T_STORE_GPR31         l.sw    0x84(r0),r31
 113#define EXCEPTION_T_LOAD_GPR31(reg)     l.lwz   reg,0x84(r0)
 114
 115/* =========================================================[ macros ]=== */
 116
 117
 118#define GET_CURRENT_PGD(reg,t1)                                 \
 119        LOAD_SYMBOL_2_GPR(reg,current_pgd)                      ;\
 120        tophys  (t1,reg)                                        ;\
 121        l.lwz   reg,0(t1)
 122
 123
 124/*
 125 * DSCR: this is a common hook for handling exceptions. it will save
 126 *       the needed registers, set up stack and pointer to current
 127 *       then jump to the handler while enabling MMU
 128 *
 129 * PRMS: handler        - a function to jump to. it has to save the
 130 *                      remaining registers to kernel stack, call
 131 *                      appropriate arch-independant exception handler
 132 *                      and finaly jump to ret_from_except
 133 *
 134 * PREQ: unchanged state from the time exception happened
 135 *
 136 * POST: SAVED the following registers original value
 137 *             to the new created exception frame pointed to by r1
 138 *
 139 *       r1  - ksp      pointing to the new (exception) frame
 140 *       r4  - EEAR     exception EA
 141 *       r10 - current  pointing to current_thread_info struct
 142 *       r12 - syscall  0, since we didn't come from syscall
 143 *       r13 - temp     it actually contains new SR, not needed anymore
 144 *       r31 - handler  address of the handler we'll jump to
 145 *
 146 *       handler has to save remaining registers to the exception
 147 *       ksp frame *before* tainting them!
 148 *
 149 * NOTE: this function is not reentrant per se. reentrancy is guaranteed
 150 *       by processor disabling all exceptions/interrupts when exception
 151 *       accours.
 152 *
 153 * OPTM: no need to make it so wasteful to extract ksp when in user mode
 154 */
 155
 156#define EXCEPTION_HANDLE(handler)                               \
 157        EXCEPTION_T_STORE_GPR30                                 ;\
 158        l.mfspr r30,r0,SPR_ESR_BASE                             ;\
 159        l.andi  r30,r30,SPR_SR_SM                               ;\
 160        l.sfeqi r30,0                                           ;\
 161        EXCEPTION_T_STORE_GPR10                                 ;\
 162        l.bnf   2f                            /* kernel_mode */ ;\
 163         EXCEPTION_T_STORE_SP                 /* delay slot */  ;\
 1641: /* user_mode:   */                                           ;\
 165        LOAD_SYMBOL_2_GPR(r1,current_thread_info_set)           ;\
 166        tophys  (r30,r1)                                        ;\
 167        /* r10: current_thread_info  */                         ;\
 168        l.lwz   r10,0(r30)                                      ;\
 169        tophys  (r30,r10)                                       ;\
 170        l.lwz   r1,(TI_KSP)(r30)                                ;\
 171        /* fall through */                                      ;\
 1722: /* kernel_mode: */                                           ;\
 173        /* create new stack frame, save only needed gprs */     ;\
 174        /* r1: KSP, r10: current, r4: EEAR, r31: __pa(KSP) */   ;\
 175        /* r12: temp, syscall indicator */                      ;\
 176        l.addi  r1,r1,-(INT_FRAME_SIZE)                         ;\
 177        /* r1 is KSP, r30 is __pa(KSP) */                       ;\
 178        tophys  (r30,r1)                                        ;\
 179        l.sw    PT_GPR12(r30),r12                               ;\
 180        l.mfspr r12,r0,SPR_EPCR_BASE                            ;\
 181        l.sw    PT_PC(r30),r12                                  ;\
 182        l.mfspr r12,r0,SPR_ESR_BASE                             ;\
 183        l.sw    PT_SR(r30),r12                                  ;\
 184        /* save r30 */                                          ;\
 185        EXCEPTION_T_LOAD_GPR30(r12)                             ;\
 186        l.sw    PT_GPR30(r30),r12                               ;\
 187        /* save r10 as was prior to exception */                ;\
 188        EXCEPTION_T_LOAD_GPR10(r12)                             ;\
 189        l.sw    PT_GPR10(r30),r12                               ;\
 190        /* save PT_SP as was prior to exception */              ;\
 191        EXCEPTION_T_LOAD_SP(r12)                                ;\
 192        l.sw    PT_SP(r30),r12                                  ;\
 193        /* save exception r4, set r4 = EA */                    ;\
 194        l.sw    PT_GPR4(r30),r4                                 ;\
 195        l.mfspr r4,r0,SPR_EEAR_BASE                             ;\
 196        /* r12 == 1 if we come from syscall */                  ;\
 197        CLEAR_GPR(r12)                                          ;\
 198        /* ----- turn on MMU ----- */                           ;\
 199        l.ori   r30,r0,(EXCEPTION_SR)                           ;\
 200        l.mtspr r0,r30,SPR_ESR_BASE                             ;\
 201        /* r30: EA address of handler */                        ;\
 202        LOAD_SYMBOL_2_GPR(r30,handler)                          ;\
 203        l.mtspr r0,r30,SPR_EPCR_BASE                            ;\
 204        l.rfe
 205
 206/*
 207 * this doesn't work
 208 *
 209 *
 210 * #ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION
 211 * #define UNHANDLED_EXCEPTION(handler)                         \
 212 *      l.ori   r3,r0,0x1                                       ;\
 213 *      l.mtspr r0,r3,SPR_SR                                    ;\
 214 *      l.movhi r3,hi(0xf0000100)                               ;\
 215 *      l.ori   r3,r3,lo(0xf0000100)                            ;\
 216 *      l.jr    r3                                              ;\
 217 *      l.nop   1
 218 *
 219 * #endif
 220 */
 221
 222/* DSCR: this is the same as EXCEPTION_HANDLE(), we are just
 223 *       a bit more carefull (if we have a PT_SP or current pointer
 224 *       corruption) and set them up from 'current_set'
 225 *
 226 */
 227#define UNHANDLED_EXCEPTION(handler)                            \
 228        EXCEPTION_T_STORE_GPR31                                 ;\
 229        EXCEPTION_T_STORE_GPR10                                 ;\
 230        EXCEPTION_T_STORE_SP                                    ;\
 231        /* temporary store r3, r9 into r1, r10 */               ;\
 232        l.addi  r1,r3,0x0                                       ;\
 233        l.addi  r10,r9,0x0                                      ;\
 234        /* the string referenced by r3 must be low enough */    ;\
 235        l.jal   _emergency_print                                ;\
 236        l.ori   r3,r0,lo(_string_unhandled_exception)           ;\
 237        l.mfspr r3,r0,SPR_NPC                                   ;\
 238        l.jal   _emergency_print_nr                             ;\
 239        l.andi  r3,r3,0x1f00                                    ;\
 240        /* the string referenced by r3 must be low enough */    ;\
 241        l.jal   _emergency_print                                ;\
 242        l.ori   r3,r0,lo(_string_epc_prefix)                    ;\
 243        l.jal   _emergency_print_nr                             ;\
 244        l.mfspr r3,r0,SPR_EPCR_BASE                             ;\
 245        l.jal   _emergency_print                                ;\
 246        l.ori   r3,r0,lo(_string_nl)                            ;\
 247        /* end of printing */                                   ;\
 248        l.addi  r3,r1,0x0                                       ;\
 249        l.addi  r9,r10,0x0                                      ;\
 250        /* extract current, ksp from current_set */             ;\
 251        LOAD_SYMBOL_2_GPR(r1,_unhandled_stack_top)              ;\
 252        LOAD_SYMBOL_2_GPR(r10,init_thread_union)                ;\
 253        /* create new stack frame, save only needed gprs */     ;\
 254        /* r1: KSP, r10: current, r31: __pa(KSP) */             ;\
 255        /* r12: temp, syscall indicator, r13 temp */            ;\
 256        l.addi  r1,r1,-(INT_FRAME_SIZE)                         ;\
 257        /* r1 is KSP, r31 is __pa(KSP) */                       ;\
 258        tophys  (r31,r1)                                        ;\
 259        l.sw    PT_GPR12(r31),r12                                       ;\
 260        l.mfspr r12,r0,SPR_EPCR_BASE                            ;\
 261        l.sw    PT_PC(r31),r12                                  ;\
 262        l.mfspr r12,r0,SPR_ESR_BASE                             ;\
 263        l.sw    PT_SR(r31),r12                                  ;\
 264        /* save r31 */                                          ;\
 265        EXCEPTION_T_LOAD_GPR31(r12)                             ;\
 266        l.sw    PT_GPR31(r31),r12                                       ;\
 267        /* save r10 as was prior to exception */                ;\
 268        EXCEPTION_T_LOAD_GPR10(r12)                             ;\
 269        l.sw    PT_GPR10(r31),r12                                       ;\
 270        /* save PT_SP as was prior to exception */                      ;\
 271        EXCEPTION_T_LOAD_SP(r12)                                ;\
 272        l.sw    PT_SP(r31),r12                                  ;\
 273        l.sw    PT_GPR13(r31),r13                                       ;\
 274        /* --> */                                               ;\
 275        /* save exception r4, set r4 = EA */                    ;\
 276        l.sw    PT_GPR4(r31),r4                                 ;\
 277        l.mfspr r4,r0,SPR_EEAR_BASE                             ;\
 278        /* r12 == 1 if we come from syscall */                  ;\
 279        CLEAR_GPR(r12)                                          ;\
 280        /* ----- play a MMU trick ----- */                      ;\
 281        l.ori   r31,r0,(EXCEPTION_SR)                           ;\
 282        l.mtspr r0,r31,SPR_ESR_BASE                             ;\
 283        /* r31: EA address of handler */                        ;\
 284        LOAD_SYMBOL_2_GPR(r31,handler)                          ;\
 285        l.mtspr r0,r31,SPR_EPCR_BASE                            ;\
 286        l.rfe
 287
 288/* =====================================================[ exceptions] === */
 289
 290/* ---[ 0x100: RESET exception ]----------------------------------------- */
 291    .org 0x100
 292        /* Jump to .init code at _start which lives in the .head section
 293         * and will be discarded after boot.
 294         */
 295        LOAD_SYMBOL_2_GPR(r15, _start)
 296        tophys  (r13,r15)                       /* MMU disabled */
 297        l.jr    r13
 298         l.nop
 299
 300/* ---[ 0x200: BUS exception ]------------------------------------------- */
 301    .org 0x200
 302_dispatch_bus_fault:
 303        EXCEPTION_HANDLE(_bus_fault_handler)
 304
 305/* ---[ 0x300: Data Page Fault exception ]------------------------------- */
 306    .org 0x300
 307_dispatch_do_dpage_fault:
 308//      totaly disable timer interrupt
 309//      l.mtspr r0,r0,SPR_TTMR
 310//      DEBUG_TLB_PROBE(0x300)
 311//      EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x300)
 312        EXCEPTION_HANDLE(_data_page_fault_handler)
 313
 314/* ---[ 0x400: Insn Page Fault exception ]------------------------------- */
 315    .org 0x400
 316_dispatch_do_ipage_fault:
 317//      totaly disable timer interrupt
 318//      l.mtspr r0,r0,SPR_TTMR
 319//      DEBUG_TLB_PROBE(0x400)
 320//      EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x400)
 321        EXCEPTION_HANDLE(_insn_page_fault_handler)
 322
 323/* ---[ 0x500: Timer exception ]----------------------------------------- */
 324    .org 0x500
 325        EXCEPTION_HANDLE(_timer_handler)
 326
 327/* ---[ 0x600: Aligment exception ]-------------------------------------- */
 328    .org 0x600
 329        EXCEPTION_HANDLE(_alignment_handler)
 330
 331/* ---[ 0x700: Illegal insn exception ]---------------------------------- */
 332    .org 0x700
 333        EXCEPTION_HANDLE(_illegal_instruction_handler)
 334
 335/* ---[ 0x800: External interrupt exception ]---------------------------- */
 336    .org 0x800
 337        EXCEPTION_HANDLE(_external_irq_handler)
 338
 339/* ---[ 0x900: DTLB miss exception ]------------------------------------- */
 340    .org 0x900
 341        l.j     boot_dtlb_miss_handler
 342        l.nop
 343
 344/* ---[ 0xa00: ITLB miss exception ]------------------------------------- */
 345    .org 0xa00
 346        l.j     boot_itlb_miss_handler
 347        l.nop
 348
 349/* ---[ 0xb00: Range exception ]----------------------------------------- */
 350    .org 0xb00
 351        UNHANDLED_EXCEPTION(_vector_0xb00)
 352
 353/* ---[ 0xc00: Syscall exception ]--------------------------------------- */
 354    .org 0xc00
 355        EXCEPTION_HANDLE(_sys_call_handler)
 356
 357/* ---[ 0xd00: Trap exception ]------------------------------------------ */
 358    .org 0xd00
 359        UNHANDLED_EXCEPTION(_vector_0xd00)
 360
 361/* ---[ 0xe00: Trap exception ]------------------------------------------ */
 362    .org 0xe00
 363//      UNHANDLED_EXCEPTION(_vector_0xe00)
 364        EXCEPTION_HANDLE(_trap_handler)
 365
 366/* ---[ 0xf00: Reserved exception ]-------------------------------------- */
 367    .org 0xf00
 368        UNHANDLED_EXCEPTION(_vector_0xf00)
 369
 370/* ---[ 0x1000: Reserved exception ]------------------------------------- */
 371    .org 0x1000
 372        UNHANDLED_EXCEPTION(_vector_0x1000)
 373
 374/* ---[ 0x1100: Reserved exception ]------------------------------------- */
 375    .org 0x1100
 376        UNHANDLED_EXCEPTION(_vector_0x1100)
 377
 378/* ---[ 0x1200: Reserved exception ]------------------------------------- */
 379    .org 0x1200
 380        UNHANDLED_EXCEPTION(_vector_0x1200)
 381
 382/* ---[ 0x1300: Reserved exception ]------------------------------------- */
 383    .org 0x1300
 384        UNHANDLED_EXCEPTION(_vector_0x1300)
 385
 386/* ---[ 0x1400: Reserved exception ]------------------------------------- */
 387    .org 0x1400
 388        UNHANDLED_EXCEPTION(_vector_0x1400)
 389
 390/* ---[ 0x1500: Reserved exception ]------------------------------------- */
 391    .org 0x1500
 392        UNHANDLED_EXCEPTION(_vector_0x1500)
 393
 394/* ---[ 0x1600: Reserved exception ]------------------------------------- */
 395    .org 0x1600
 396        UNHANDLED_EXCEPTION(_vector_0x1600)
 397
 398/* ---[ 0x1700: Reserved exception ]------------------------------------- */
 399    .org 0x1700
 400        UNHANDLED_EXCEPTION(_vector_0x1700)
 401
 402/* ---[ 0x1800: Reserved exception ]------------------------------------- */
 403    .org 0x1800
 404        UNHANDLED_EXCEPTION(_vector_0x1800)
 405
 406/* ---[ 0x1900: Reserved exception ]------------------------------------- */
 407    .org 0x1900
 408        UNHANDLED_EXCEPTION(_vector_0x1900)
 409
 410/* ---[ 0x1a00: Reserved exception ]------------------------------------- */
 411    .org 0x1a00
 412        UNHANDLED_EXCEPTION(_vector_0x1a00)
 413
 414/* ---[ 0x1b00: Reserved exception ]------------------------------------- */
 415    .org 0x1b00
 416        UNHANDLED_EXCEPTION(_vector_0x1b00)
 417
 418/* ---[ 0x1c00: Reserved exception ]------------------------------------- */
 419    .org 0x1c00
 420        UNHANDLED_EXCEPTION(_vector_0x1c00)
 421
 422/* ---[ 0x1d00: Reserved exception ]------------------------------------- */
 423    .org 0x1d00
 424        UNHANDLED_EXCEPTION(_vector_0x1d00)
 425
 426/* ---[ 0x1e00: Reserved exception ]------------------------------------- */
 427    .org 0x1e00
 428        UNHANDLED_EXCEPTION(_vector_0x1e00)
 429
 430/* ---[ 0x1f00: Reserved exception ]------------------------------------- */
 431    .org 0x1f00
 432        UNHANDLED_EXCEPTION(_vector_0x1f00)
 433
 434    .org 0x2000
 435/* ===================================================[ kernel start ]=== */
 436
 437/*    .text*/
 438
 439/* This early stuff belongs in HEAD, but some of the functions below definitely
 440 * don't... */
 441
 442        __HEAD
 443        .global _start
 444_start:
 445        /* save kernel parameters */
 446        l.or    r25,r0,r3       /* pointer to fdt */
 447
 448        /*
 449         * ensure a deterministic start
 450         */
 451
 452        l.ori   r3,r0,0x1
 453        l.mtspr r0,r3,SPR_SR
 454
 455        CLEAR_GPR(r1)
 456        CLEAR_GPR(r2)
 457        CLEAR_GPR(r3)
 458        CLEAR_GPR(r4)
 459        CLEAR_GPR(r5)
 460        CLEAR_GPR(r6)
 461        CLEAR_GPR(r7)
 462        CLEAR_GPR(r8)
 463        CLEAR_GPR(r9)
 464        CLEAR_GPR(r10)
 465        CLEAR_GPR(r11)
 466        CLEAR_GPR(r12)
 467        CLEAR_GPR(r13)
 468        CLEAR_GPR(r14)
 469        CLEAR_GPR(r15)
 470        CLEAR_GPR(r16)
 471        CLEAR_GPR(r17)
 472        CLEAR_GPR(r18)
 473        CLEAR_GPR(r19)
 474        CLEAR_GPR(r20)
 475        CLEAR_GPR(r21)
 476        CLEAR_GPR(r22)
 477        CLEAR_GPR(r23)
 478        CLEAR_GPR(r24)
 479        CLEAR_GPR(r26)
 480        CLEAR_GPR(r27)
 481        CLEAR_GPR(r28)
 482        CLEAR_GPR(r29)
 483        CLEAR_GPR(r30)
 484        CLEAR_GPR(r31)
 485
 486        /*
 487         * set up initial ksp and current
 488         */
 489        LOAD_SYMBOL_2_GPR(r1,init_thread_union+0x2000)  // setup kernel stack
 490        LOAD_SYMBOL_2_GPR(r10,init_thread_union)        // setup current
 491        tophys  (r31,r10)
 492        l.sw    TI_KSP(r31), r1
 493
 494        l.ori   r4,r0,0x0
 495
 496
 497        /*
 498         * .data contains initialized data,
 499         * .bss contains uninitialized data - clear it up
 500         */
 501clear_bss:
 502        LOAD_SYMBOL_2_GPR(r24, __bss_start)
 503        LOAD_SYMBOL_2_GPR(r26, _end)
 504        tophys(r28,r24)
 505        tophys(r30,r26)
 506        CLEAR_GPR(r24)
 507        CLEAR_GPR(r26)
 5081:
 509        l.sw    (0)(r28),r0
 510        l.sfltu r28,r30
 511        l.bf    1b
 512        l.addi  r28,r28,4
 513
 514enable_ic:
 515        l.jal   _ic_enable
 516         l.nop
 517
 518enable_dc:
 519        l.jal   _dc_enable
 520         l.nop
 521
 522flush_tlb:
 523        /*
 524         *  I N V A L I D A T E   T L B   e n t r i e s
 525         */
 526        LOAD_SYMBOL_2_GPR(r5,SPR_DTLBMR_BASE(0))
 527        LOAD_SYMBOL_2_GPR(r6,SPR_ITLBMR_BASE(0))
 528        l.addi  r7,r0,128 /* Maximum number of sets */
 5291:
 530        l.mtspr r5,r0,0x0
 531        l.mtspr r6,r0,0x0
 532
 533        l.addi  r5,r5,1
 534        l.addi  r6,r6,1
 535        l.sfeq  r7,r0
 536        l.bnf   1b
 537         l.addi r7,r7,-1
 538
 539
 540/* The MMU needs to be enabled before or32_early_setup is called */
 541
 542enable_mmu:
 543        /*
 544         * enable dmmu & immu
 545         * SR[5] = 0, SR[6] = 0, 6th and 7th bit of SR set to 0
 546         */
 547        l.mfspr r30,r0,SPR_SR
 548        l.movhi r28,hi(SPR_SR_DME | SPR_SR_IME)
 549        l.ori   r28,r28,lo(SPR_SR_DME | SPR_SR_IME)
 550        l.or    r30,r30,r28
 551        l.mtspr r0,r30,SPR_SR
 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        l.nop
 565        l.nop
 566        l.nop
 567        l.nop
 568
 569        // reset the simulation counters
 570        l.nop 5
 571
 572        /* check fdt header magic word */
 573        l.lwz   r3,0(r25)       /* load magic from fdt into r3 */
 574        l.movhi r4,hi(OF_DT_HEADER)
 575        l.ori   r4,r4,lo(OF_DT_HEADER)
 576        l.sfeq  r3,r4
 577        l.bf    _fdt_found
 578         l.nop
 579        /* magic number mismatch, set fdt pointer to null */
 580        l.or    r25,r0,r0
 581_fdt_found:
 582        /* pass fdt pointer to or32_early_setup in r3 */
 583        l.or    r3,r0,r25
 584        LOAD_SYMBOL_2_GPR(r24, or32_early_setup)
 585        l.jalr r24
 586         l.nop
 587
 588clear_regs:
 589        /*
 590         * clear all GPRS to increase determinism
 591         */
 592        CLEAR_GPR(r2)
 593        CLEAR_GPR(r3)
 594        CLEAR_GPR(r4)
 595        CLEAR_GPR(r5)
 596        CLEAR_GPR(r6)
 597        CLEAR_GPR(r7)
 598        CLEAR_GPR(r8)
 599        CLEAR_GPR(r9)
 600        CLEAR_GPR(r11)
 601        CLEAR_GPR(r12)
 602        CLEAR_GPR(r13)
 603        CLEAR_GPR(r14)
 604        CLEAR_GPR(r15)
 605        CLEAR_GPR(r16)
 606        CLEAR_GPR(r17)
 607        CLEAR_GPR(r18)
 608        CLEAR_GPR(r19)
 609        CLEAR_GPR(r20)
 610        CLEAR_GPR(r21)
 611        CLEAR_GPR(r22)
 612        CLEAR_GPR(r23)
 613        CLEAR_GPR(r24)
 614        CLEAR_GPR(r25)
 615        CLEAR_GPR(r26)
 616        CLEAR_GPR(r27)
 617        CLEAR_GPR(r28)
 618        CLEAR_GPR(r29)
 619        CLEAR_GPR(r30)
 620        CLEAR_GPR(r31)
 621
 622jump_start_kernel:
 623        /*
 624         * jump to kernel entry (start_kernel)
 625         */
 626        LOAD_SYMBOL_2_GPR(r30, start_kernel)
 627        l.jr    r30
 628         l.nop
 629
 630/* ========================================[ cache ]=== */
 631
 632        /* aligment here so we don't change memory offsets with
 633         * memory controler defined
 634         */
 635        .align 0x2000
 636
 637_ic_enable:
 638        /* Check if IC present and skip enabling otherwise */
 639        l.mfspr r24,r0,SPR_UPR
 640        l.andi  r26,r24,SPR_UPR_ICP
 641        l.sfeq  r26,r0
 642        l.bf    9f
 643        l.nop
 644
 645        /* Disable IC */
 646        l.mfspr r6,r0,SPR_SR
 647        l.addi  r5,r0,-1
 648        l.xori  r5,r5,SPR_SR_ICE
 649        l.and   r5,r6,r5
 650        l.mtspr r0,r5,SPR_SR
 651
 652        /* Establish cache block size
 653           If BS=0, 16;
 654           If BS=1, 32;
 655           r14 contain block size
 656        */
 657        l.mfspr r24,r0,SPR_ICCFGR
 658        l.andi  r26,r24,SPR_ICCFGR_CBS
 659        l.srli  r28,r26,7
 660        l.ori   r30,r0,16
 661        l.sll   r14,r30,r28
 662
 663        /* Establish number of cache sets
 664           r16 contains number of cache sets
 665           r28 contains log(# of cache sets)
 666        */
 667        l.andi  r26,r24,SPR_ICCFGR_NCS
 668        l.srli  r28,r26,3
 669        l.ori   r30,r0,1
 670        l.sll   r16,r30,r28
 671
 672        /* Invalidate IC */
 673        l.addi  r6,r0,0
 674        l.sll   r5,r14,r28
 675//        l.mul   r5,r14,r16
 676//      l.trap  1
 677//      l.addi  r5,r0,IC_SIZE
 6781:
 679        l.mtspr r0,r6,SPR_ICBIR
 680        l.sfne  r6,r5
 681        l.bf    1b
 682        l.add   r6,r6,r14
 683 //       l.addi   r6,r6,IC_LINE
 684
 685        /* Enable IC */
 686        l.mfspr r6,r0,SPR_SR
 687        l.ori   r6,r6,SPR_SR_ICE
 688        l.mtspr r0,r6,SPR_SR
 689        l.nop
 690        l.nop
 691        l.nop
 692        l.nop
 693        l.nop
 694        l.nop
 695        l.nop
 696        l.nop
 697        l.nop
 698        l.nop
 6999:
 700        l.jr    r9
 701        l.nop
 702
 703_dc_enable:
 704        /* Check if DC present and skip enabling otherwise */
 705        l.mfspr r24,r0,SPR_UPR
 706        l.andi  r26,r24,SPR_UPR_DCP
 707        l.sfeq  r26,r0
 708        l.bf    9f
 709        l.nop
 710
 711        /* Disable DC */
 712        l.mfspr r6,r0,SPR_SR
 713        l.addi  r5,r0,-1
 714        l.xori  r5,r5,SPR_SR_DCE
 715        l.and   r5,r6,r5
 716        l.mtspr r0,r5,SPR_SR
 717
 718        /* Establish cache block size
 719           If BS=0, 16;
 720           If BS=1, 32;
 721           r14 contain block size
 722        */
 723        l.mfspr r24,r0,SPR_DCCFGR
 724        l.andi  r26,r24,SPR_DCCFGR_CBS
 725        l.srli  r28,r26,7
 726        l.ori   r30,r0,16
 727        l.sll   r14,r30,r28
 728
 729        /* Establish number of cache sets
 730           r16 contains number of cache sets
 731           r28 contains log(# of cache sets)
 732        */
 733        l.andi  r26,r24,SPR_DCCFGR_NCS
 734        l.srli  r28,r26,3
 735        l.ori   r30,r0,1
 736        l.sll   r16,r30,r28
 737
 738        /* Invalidate DC */
 739        l.addi  r6,r0,0
 740        l.sll   r5,r14,r28
 7411:
 742        l.mtspr r0,r6,SPR_DCBIR
 743        l.sfne  r6,r5
 744        l.bf    1b
 745        l.add   r6,r6,r14
 746
 747        /* Enable DC */
 748        l.mfspr r6,r0,SPR_SR
 749        l.ori   r6,r6,SPR_SR_DCE
 750        l.mtspr r0,r6,SPR_SR
 7519:
 752        l.jr    r9
 753        l.nop
 754
 755/* ===============================================[ page table masks ]=== */
 756
 757#define DTLB_UP_CONVERT_MASK  0x3fa
 758#define ITLB_UP_CONVERT_MASK  0x3a
 759
 760/* for SMP we'd have (this is a bit subtle, CC must be always set
 761 * for SMP, but since we have _PAGE_PRESENT bit always defined
 762 * we can just modify the mask)
 763 */
 764#define DTLB_SMP_CONVERT_MASK  0x3fb
 765#define ITLB_SMP_CONVERT_MASK  0x3b
 766
 767/* ---[ boot dtlb miss handler ]----------------------------------------- */
 768
 769boot_dtlb_miss_handler:
 770
 771/* mask for DTLB_MR register: - (0) sets V (valid) bit,
 772 *                            - (31-12) sets bits belonging to VPN (31-12)
 773 */
 774#define DTLB_MR_MASK 0xfffff001
 775
 776/* mask for DTLB_TR register: - (2) sets CI (cache inhibit) bit,
 777 *                            - (4) sets A (access) bit,
 778 *                            - (5) sets D (dirty) bit,
 779 *                            - (8) sets SRE (superuser read) bit
 780 *                            - (9) sets SWE (superuser write) bit
 781 *                            - (31-12) sets bits belonging to VPN (31-12)
 782 */
 783#define DTLB_TR_MASK 0xfffff332
 784
 785/* These are for masking out the VPN/PPN value from the MR/TR registers...
 786 * it's not the same as the PFN */
 787#define VPN_MASK 0xfffff000
 788#define PPN_MASK 0xfffff000
 789
 790
 791        EXCEPTION_STORE_GPR6
 792
 793#if 0
 794        l.mfspr r6,r0,SPR_ESR_BASE         //
 795        l.andi  r6,r6,SPR_SR_SM            // are we in kernel mode ?
 796        l.sfeqi r6,0                       // r6 == 0x1 --> SM
 797        l.bf    exit_with_no_dtranslation  //
 798        l.nop
 799#endif
 800
 801        /* this could be optimized by moving storing of
 802         * non r6 registers here, and jumping r6 restore
 803         * if not in supervisor mode
 804         */
 805
 806        EXCEPTION_STORE_GPR2
 807        EXCEPTION_STORE_GPR3
 808        EXCEPTION_STORE_GPR4
 809        EXCEPTION_STORE_GPR5
 810
 811        l.mfspr r4,r0,SPR_EEAR_BASE        // get the offending EA
 812
 813immediate_translation:
 814        CLEAR_GPR(r6)
 815
 816        l.srli  r3,r4,0xd                  // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
 817
 818        l.mfspr r6, r0, SPR_DMMUCFGR
 819        l.andi  r6, r6, SPR_DMMUCFGR_NTS
 820        l.srli  r6, r6, SPR_DMMUCFGR_NTS_OFF
 821        l.ori   r5, r0, 0x1
 822        l.sll   r5, r5, r6      // r5 = number DMMU sets
 823        l.addi  r6, r5, -1      // r6 = nsets mask
 824        l.and   r2, r3, r6      // r2 <- r3 % NSETS_MASK
 825
 826        l.or    r6,r6,r4                   // r6 <- r4
 827        l.ori   r6,r6,~(VPN_MASK)          // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
 828        l.movhi r5,hi(DTLB_MR_MASK)        // r5 <- ffff:0000.x000
 829        l.ori   r5,r5,lo(DTLB_MR_MASK)     // r5 <- ffff:1111.x001 - apply DTLB_MR_MASK
 830        l.and   r5,r5,r6                   // r5 <- VPN :VPN .x001 - we have DTLBMR entry
 831        l.mtspr r2,r5,SPR_DTLBMR_BASE(0)   // set DTLBMR
 832
 833        /* set up DTLB with no translation for EA <= 0xbfffffff */
 834        LOAD_SYMBOL_2_GPR(r6,0xbfffffff)
 835        l.sfgeu  r6,r4                     // flag if r6 >= r4 (if 0xbfffffff >= EA)
 836        l.bf     1f                        // goto out
 837        l.and    r3,r4,r4                  // delay slot :: 24 <- r4 (if flag==1)
 838
 839        tophys(r3,r4)                      // r3 <- PA
 8401:
 841        l.ori   r3,r3,~(PPN_MASK)          // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
 842        l.movhi r5,hi(DTLB_TR_MASK)        // r5 <- ffff:0000.x000
 843        l.ori   r5,r5,lo(DTLB_TR_MASK)     // r5 <- ffff:1111.x330 - apply DTLB_MR_MASK
 844        l.and   r5,r5,r3                   // r5 <- PPN :PPN .x330 - we have DTLBTR entry
 845        l.mtspr r2,r5,SPR_DTLBTR_BASE(0)   // set DTLBTR
 846
 847        EXCEPTION_LOAD_GPR6
 848        EXCEPTION_LOAD_GPR5
 849        EXCEPTION_LOAD_GPR4
 850        EXCEPTION_LOAD_GPR3
 851        EXCEPTION_LOAD_GPR2
 852
 853        l.rfe                              // SR <- ESR, PC <- EPC
 854
 855exit_with_no_dtranslation:
 856        /* EA out of memory or not in supervisor mode */
 857        EXCEPTION_LOAD_GPR6
 858        EXCEPTION_LOAD_GPR4
 859        l.j     _dispatch_bus_fault
 860
 861/* ---[ boot itlb miss handler ]----------------------------------------- */
 862
 863boot_itlb_miss_handler:
 864
 865/* mask for ITLB_MR register: - sets V (valid) bit,
 866 *                            - sets bits belonging to VPN (15-12)
 867 */
 868#define ITLB_MR_MASK 0xfffff001
 869
 870/* mask for ITLB_TR register: - sets A (access) bit,
 871 *                            - sets SXE (superuser execute) bit
 872 *                            - sets bits belonging to VPN (15-12)
 873 */
 874#define ITLB_TR_MASK 0xfffff050
 875
 876/*
 877#define VPN_MASK 0xffffe000
 878#define PPN_MASK 0xffffe000
 879*/
 880
 881
 882
 883        EXCEPTION_STORE_GPR2
 884        EXCEPTION_STORE_GPR3
 885        EXCEPTION_STORE_GPR4
 886        EXCEPTION_STORE_GPR5
 887        EXCEPTION_STORE_GPR6
 888
 889#if 0
 890        l.mfspr r6,r0,SPR_ESR_BASE         //
 891        l.andi  r6,r6,SPR_SR_SM            // are we in kernel mode ?
 892        l.sfeqi r6,0                       // r6 == 0x1 --> SM
 893        l.bf    exit_with_no_itranslation
 894        l.nop
 895#endif
 896
 897
 898        l.mfspr r4,r0,SPR_EEAR_BASE        // get the offending EA
 899
 900earlyearly:
 901        CLEAR_GPR(r6)
 902
 903        l.srli  r3,r4,0xd                  // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
 904
 905        l.mfspr r6, r0, SPR_IMMUCFGR
 906        l.andi  r6, r6, SPR_IMMUCFGR_NTS
 907        l.srli  r6, r6, SPR_IMMUCFGR_NTS_OFF
 908        l.ori   r5, r0, 0x1
 909        l.sll   r5, r5, r6      // r5 = number IMMU sets from IMMUCFGR
 910        l.addi  r6, r5, -1      // r6 = nsets mask
 911        l.and   r2, r3, r6      // r2 <- r3 % NSETS_MASK
 912
 913        l.or    r6,r6,r4                   // r6 <- r4
 914        l.ori   r6,r6,~(VPN_MASK)          // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
 915        l.movhi r5,hi(ITLB_MR_MASK)        // r5 <- ffff:0000.x000
 916        l.ori   r5,r5,lo(ITLB_MR_MASK)     // r5 <- ffff:1111.x001 - apply ITLB_MR_MASK
 917        l.and   r5,r5,r6                   // r5 <- VPN :VPN .x001 - we have ITLBMR entry
 918        l.mtspr r2,r5,SPR_ITLBMR_BASE(0)   // set ITLBMR
 919
 920        /*
 921         * set up ITLB with no translation for EA <= 0x0fffffff
 922         *
 923         * we need this for head.S mapping (EA = PA). if we move all functions
 924         * which run with mmu enabled into entry.S, we might be able to eliminate this.
 925         *
 926         */
 927        LOAD_SYMBOL_2_GPR(r6,0x0fffffff)
 928        l.sfgeu  r6,r4                     // flag if r6 >= r4 (if 0xb0ffffff >= EA)
 929        l.bf     1f                        // goto out
 930        l.and    r3,r4,r4                  // delay slot :: 24 <- r4 (if flag==1)
 931
 932        tophys(r3,r4)                      // r3 <- PA
 9331:
 934        l.ori   r3,r3,~(PPN_MASK)          // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
 935        l.movhi r5,hi(ITLB_TR_MASK)        // r5 <- ffff:0000.x000
 936        l.ori   r5,r5,lo(ITLB_TR_MASK)     // r5 <- ffff:1111.x050 - apply ITLB_MR_MASK
 937        l.and   r5,r5,r3                   // r5 <- PPN :PPN .x050 - we have ITLBTR entry
 938        l.mtspr r2,r5,SPR_ITLBTR_BASE(0)   // set ITLBTR
 939
 940        EXCEPTION_LOAD_GPR6
 941        EXCEPTION_LOAD_GPR5
 942        EXCEPTION_LOAD_GPR4
 943        EXCEPTION_LOAD_GPR3
 944        EXCEPTION_LOAD_GPR2
 945
 946        l.rfe                              // SR <- ESR, PC <- EPC
 947
 948exit_with_no_itranslation:
 949        EXCEPTION_LOAD_GPR4
 950        EXCEPTION_LOAD_GPR6
 951        l.j    _dispatch_bus_fault
 952        l.nop
 953
 954/* ====================================================================== */
 955/*
 956 * Stuff below here shouldn't go into .head section... maybe this stuff
 957 * can be moved to entry.S ???
 958 */
 959
 960/* ==============================================[ DTLB miss handler ]=== */
 961
 962/*
 963 * Comments:
 964 *   Exception handlers are entered with MMU off so the following handler
 965 *   needs to use physical addressing
 966 *
 967 */
 968
 969        .text
 970ENTRY(dtlb_miss_handler)
 971        EXCEPTION_STORE_GPR2
 972        EXCEPTION_STORE_GPR3
 973        EXCEPTION_STORE_GPR4
 974        EXCEPTION_STORE_GPR5
 975        EXCEPTION_STORE_GPR6
 976        /*
 977         * get EA of the miss
 978         */
 979        l.mfspr r2,r0,SPR_EEAR_BASE
 980        /*
 981         * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
 982         */
 983        GET_CURRENT_PGD(r3,r5)          // r3 is current_pgd, r5 is temp
 984        l.srli  r4,r2,0x18              // >> PAGE_SHIFT + (PAGE_SHIFT - 2)
 985        l.slli  r4,r4,0x2               // to get address << 2
 986        l.add   r5,r4,r3                // r4 is pgd_index(daddr)
 987        /*
 988         * if (pmd_none(*pmd))
 989         *   goto pmd_none:
 990         */
 991        tophys  (r4,r5)
 992        l.lwz   r3,0x0(r4)              // get *pmd value
 993        l.sfne  r3,r0
 994        l.bnf   d_pmd_none
 995         l.andi r3,r3,~PAGE_MASK //0x1fff               // ~PAGE_MASK
 996        /*
 997         * if (pmd_bad(*pmd))
 998         *   pmd_clear(pmd)
 999         *   goto pmd_bad:
1000         */

1001//      l.sfeq  r3,r0                   // check *pmd value
1002//      l.bf    d_pmd_good
1003        l.addi  r3,r0,0xffffe000        // PAGE_MASK
1004//      l.j     d_pmd_bad
1005//      l.sw    0x0(r4),r0              // clear pmd
1006d_pmd_good:
1007        /*
1008         * pte = *pte_offset(pmd, daddr);
1009         */
1010        l.lwz   r4,0x0(r4)              // get **pmd value
1011        l.and   r4,r4,r3                // & PAGE_MASK
1012        l.srli  r5,r2,0xd               // >> PAGE_SHIFT, r2 == EEAR
1013        l.andi  r3,r5,0x7ff             // (1UL << PAGE_SHIFT - 2) - 1
1014        l.slli  r3,r3,0x2               // to get address << 2
1015        l.add   r3,r3,r4
1016        l.lwz   r2,0x0(r3)              // this is pte at last
1017        /*
1018         * if (!pte_present(pte))
1019         */
1020        l.andi  r4,r2,0x1
1021        l.sfne  r4,r0                   // is pte present
1022        l.bnf   d_pte_not_present
1023        l.addi  r3,r0,0xffffe3fa        // PAGE_MASK | DTLB_UP_CONVERT_MASK
1024        /*
1025         * fill DTLB TR register
1026         */
1027        l.and   r4,r2,r3                // apply the mask
1028        // Determine number of DMMU sets
1029        l.mfspr r6, r0, SPR_DMMUCFGR
1030        l.andi  r6, r6, SPR_DMMUCFGR_NTS
1031        l.srli  r6, r6, SPR_DMMUCFGR_NTS_OFF
1032        l.ori   r3, r0, 0x1
1033        l.sll   r3, r3, r6      // r3 = number DMMU sets DMMUCFGR
1034        l.addi  r6, r3, -1      // r6 = nsets mask
1035        l.and   r5, r5, r6      // calc offset:  & (NUM_TLB_ENTRIES-1)
1036                                                           //NUM_TLB_ENTRIES
1037        l.mtspr r5,r4,SPR_DTLBTR_BASE(0)
1038        /*
1039         * fill DTLB MR register
1040         */
1041        l.mfspr r2,r0,SPR_EEAR_BASE
1042        l.addi  r3,r0,0xffffe000        // PAGE_MASK
1043        l.and   r4,r2,r3                // apply PAGE_MASK to EA (__PHX__ do we really need this?)
1044        l.ori   r4,r4,0x1               // set hardware valid bit: DTBL_MR entry
1045        l.mtspr r5,r4,SPR_DTLBMR_BASE(0)
1046
1047        EXCEPTION_LOAD_GPR2
1048        EXCEPTION_LOAD_GPR3
1049        EXCEPTION_LOAD_GPR4
1050        EXCEPTION_LOAD_GPR5
1051        EXCEPTION_LOAD_GPR6
1052        l.rfe
1053d_pmd_bad:
1054        l.nop   1
1055        EXCEPTION_LOAD_GPR2
1056        EXCEPTION_LOAD_GPR3
1057        EXCEPTION_LOAD_GPR4
1058        EXCEPTION_LOAD_GPR5
1059        EXCEPTION_LOAD_GPR6
1060        l.rfe
1061d_pmd_none:
1062d_pte_not_present:
1063        EXCEPTION_LOAD_GPR2
1064        EXCEPTION_LOAD_GPR3
1065        EXCEPTION_LOAD_GPR4
1066        EXCEPTION_LOAD_GPR5
1067        EXCEPTION_LOAD_GPR6
1068        EXCEPTION_HANDLE(_dtlb_miss_page_fault_handler)
1069
1070/* ==============================================[ ITLB miss handler ]=== */
1071ENTRY(itlb_miss_handler)
1072        EXCEPTION_STORE_GPR2
1073        EXCEPTION_STORE_GPR3
1074        EXCEPTION_STORE_GPR4
1075        EXCEPTION_STORE_GPR5
1076        EXCEPTION_STORE_GPR6
1077        /*
1078         * get EA of the miss
1079         */
1080        l.mfspr r2,r0,SPR_EEAR_BASE
1081
1082        /*
1083         * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
1084         *
1085         */
1086        GET_CURRENT_PGD(r3,r5)          // r3 is current_pgd, r5 is temp
1087        l.srli  r4,r2,0x18              // >> PAGE_SHIFT + (PAGE_SHIFT - 2)
1088        l.slli  r4,r4,0x2               // to get address << 2
1089        l.add   r5,r4,r3                // r4 is pgd_index(daddr)
1090        /*
1091         * if (pmd_none(*pmd))
1092         *   goto pmd_none:
1093         */
1094        tophys  (r4,r5)
1095        l.lwz   r3,0x0(r4)              // get *pmd value
1096        l.sfne  r3,r0
1097        l.bnf   i_pmd_none
1098        l.andi  r3,r3,0x1fff            // ~PAGE_MASK
1099        /*
1100         * if (pmd_bad(*pmd))
1101         *   pmd_clear(pmd)
1102         *   goto pmd_bad:
1103         */
1104
1105//      l.sfeq  r3,r0                   // check *pmd value
1106//      l.bf    i_pmd_good
1107        l.addi  r3,r0,0xffffe000        // PAGE_MASK
1108//      l.j     i_pmd_bad
1109//      l.sw    0x0(r4),r0              // clear pmd
1110
1111i_pmd_good:
1112        /*
1113         * pte = *pte_offset(pmd, iaddr);
1114         *
1115         */
1116        l.lwz   r4,0x0(r4)              // get **pmd value
1117        l.and   r4,r4,r3                // & PAGE_MASK
1118        l.srli  r5,r2,0xd               // >> PAGE_SHIFT, r2 == EEAR
1119        l.andi  r3,r5,0x7ff             // (1UL << PAGE_SHIFT - 2) - 1
1120        l.slli  r3,r3,0x2               // to get address << 2
1121        l.add   r3,r3,r4
1122        l.lwz   r2,0x0(r3)              // this is pte at last
1123        /*
1124         * if (!pte_present(pte))
1125         *
1126         */
1127        l.andi  r4,r2,0x1
1128        l.sfne  r4,r0                   // is pte present
1129        l.bnf   i_pte_not_present
1130        l.addi  r3,r0,0xffffe03a        // PAGE_MASK | ITLB_UP_CONVERT_MASK
1131        /*
1132         * fill ITLB TR register
1133         */
1134        l.and   r4,r2,r3                // apply the mask
1135        l.andi  r3,r2,0x7c0             // _PAGE_EXEC | _PAGE_SRE | _PAGE_SWE |  _PAGE_URE | _PAGE_UWE
1136//      l.andi  r3,r2,0x400             // _PAGE_EXEC
1137        l.sfeq  r3,r0
1138        l.bf    itlb_tr_fill //_workaround
1139        // Determine number of IMMU sets
1140        l.mfspr r6, r0, SPR_IMMUCFGR
1141        l.andi  r6, r6, SPR_IMMUCFGR_NTS
1142        l.srli  r6, r6, SPR_IMMUCFGR_NTS_OFF
1143        l.ori   r3, r0, 0x1
1144        l.sll   r3, r3, r6      // r3 = number IMMU sets IMMUCFGR
1145        l.addi  r6, r3, -1      // r6 = nsets mask
1146        l.and   r5, r5, r6      // calc offset:  & (NUM_TLB_ENTRIES-1)
1147
1148/*
1149 * __PHX__ :: fixme
1150 * we should not just blindly set executable flags,
1151 * but it does help with ping. the clean way would be to find out
1152 * (and fix it) why stack doesn't have execution permissions
1153 */
1154
1155itlb_tr_fill_workaround:
1156        l.ori   r4,r4,0xc0              // | (SPR_ITLBTR_UXE | ITLBTR_SXE)
1157itlb_tr_fill:
1158        l.mtspr r5,r4,SPR_ITLBTR_BASE(0)
1159        /*
1160         * fill DTLB MR register
1161         */
1162        l.mfspr r2,r0,SPR_EEAR_BASE
1163        l.addi  r3,r0,0xffffe000        // PAGE_MASK
1164        l.and   r4,r2,r3                // apply PAGE_MASK to EA (__PHX__ do we really need this?)
1165        l.ori   r4,r4,0x1               // set hardware valid bit: DTBL_MR entry
1166        l.mtspr r5,r4,SPR_ITLBMR_BASE(0)
1167
1168        EXCEPTION_LOAD_GPR2
1169        EXCEPTION_LOAD_GPR3
1170        EXCEPTION_LOAD_GPR4
1171        EXCEPTION_LOAD_GPR5
1172        EXCEPTION_LOAD_GPR6
1173        l.rfe
1174
1175i_pmd_bad:
1176        l.nop   1
1177        EXCEPTION_LOAD_GPR2
1178        EXCEPTION_LOAD_GPR3
1179        EXCEPTION_LOAD_GPR4
1180        EXCEPTION_LOAD_GPR5
1181        EXCEPTION_LOAD_GPR6
1182        l.rfe
1183i_pmd_none:
1184i_pte_not_present:
1185        EXCEPTION_LOAD_GPR2
1186        EXCEPTION_LOAD_GPR3
1187        EXCEPTION_LOAD_GPR4
1188        EXCEPTION_LOAD_GPR5
1189        EXCEPTION_LOAD_GPR6
1190        EXCEPTION_HANDLE(_itlb_miss_page_fault_handler)
1191
1192/* ==============================================[ boot tlb handlers ]=== */
1193
1194
1195/* =================================================[ debugging aids ]=== */
1196
1197        .align 64
1198_immu_trampoline:
1199        .space 64
1200_immu_trampoline_top:
1201
1202#define TRAMP_SLOT_0            (0x0)
1203#define TRAMP_SLOT_1            (0x4)
1204#define TRAMP_SLOT_2            (0x8)
1205#define TRAMP_SLOT_3            (0xc)
1206#define TRAMP_SLOT_4            (0x10)
1207#define TRAMP_SLOT_5            (0x14)
1208#define TRAMP_FRAME_SIZE        (0x18)
1209
1210ENTRY(_immu_trampoline_workaround)
1211        // r2 EEA
1212        // r6 is physical EEA
1213        tophys(r6,r2)
1214
1215        LOAD_SYMBOL_2_GPR(r5,_immu_trampoline)
1216        tophys  (r3,r5)                 // r3 is trampoline (physical)
1217
1218        LOAD_SYMBOL_2_GPR(r4,0x15000000)
1219        l.sw    TRAMP_SLOT_0(r3),r4
1220        l.sw    TRAMP_SLOT_1(r3),r4
1221        l.sw    TRAMP_SLOT_4(r3),r4
1222        l.sw    TRAMP_SLOT_5(r3),r4
1223
1224                                        // EPC = EEA - 0x4
1225        l.lwz   r4,0x0(r6)              // load op @ EEA + 0x0 (fc address)
1226        l.sw    TRAMP_SLOT_3(r3),r4     // store it to _immu_trampoline_data
1227        l.lwz   r4,-0x4(r6)             // load op @ EEA - 0x4 (f8 address)
1228        l.sw    TRAMP_SLOT_2(r3),r4     // store it to _immu_trampoline_data
1229
1230        l.srli  r5,r4,26                // check opcode for write access
1231        l.sfeqi r5,0                    // l.j
1232        l.bf    0f
1233        l.sfeqi r5,0x11                 // l.jr
1234        l.bf    1f
1235        l.sfeqi r5,1                    // l.jal
1236        l.bf    2f
1237        l.sfeqi r5,0x12                 // l.jalr
1238        l.bf    3f
1239        l.sfeqi r5,3                    // l.bnf
1240        l.bf    4f
1241        l.sfeqi r5,4                    // l.bf
1242        l.bf    5f
124399:
1244        l.nop
1245        l.j     99b                     // should never happen
1246        l.nop   1
1247
1248        // r2 is EEA
1249        // r3 is trampoline address (physical)
1250        // r4 is instruction
1251        // r6 is physical(EEA)
1252        //
1253        // r5
1254
12552:      // l.jal
1256
1257        /* 19 20 aa aa  l.movhi r9,0xaaaa
1258         * a9 29 bb bb  l.ori   r9,0xbbbb
1259         *
1260         * where 0xaaaabbbb is EEA + 0x4 shifted right 2
1261         */
1262
1263        l.addi  r6,r2,0x4               // this is 0xaaaabbbb
1264
1265                                        // l.movhi r9,0xaaaa
1266        l.ori   r5,r0,0x1920            // 0x1920 == l.movhi r9
1267        l.sh    (TRAMP_SLOT_0+0x0)(r3),r5
1268        l.srli  r5,r6,16
1269        l.sh    (TRAMP_SLOT_0+0x2)(r3),r5
1270
1271                                        // l.ori   r9,0xbbbb
1272        l.ori   r5,r0,0xa929            // 0xa929 == l.ori r9
1273        l.sh    (TRAMP_SLOT_1+0x0)(r3),r5
1274        l.andi  r5,r6,0xffff
1275        l.sh    (TRAMP_SLOT_1+0x2)(r3),r5
1276
1277        /* falthrough, need to set up new jump offset */
1278
1279
12800:      // l.j
1281        l.slli  r6,r4,6                 // original offset shifted left 6 - 2
1282//      l.srli  r6,r6,6                 // original offset shifted right 2
1283
1284        l.slli  r4,r2,4                 // old jump position: EEA shifted left 4
1285//      l.srli  r4,r4,6                 // old jump position: shifted right 2
1286
1287        l.addi  r5,r3,0xc               // new jump position (physical)
1288        l.slli  r5,r5,4                 // new jump position: shifted left 4
1289
1290        // calculate new jump offset
1291        // new_off = old_off + (old_jump - new_jump)
1292
1293        l.sub   r5,r4,r5                // old_jump - new_jump
1294        l.add   r5,r6,r5                // orig_off + (old_jump - new_jump)
1295        l.srli  r5,r5,6                 // new offset shifted right 2
1296
1297        // r5 is new jump offset
1298                                        // l.j has opcode 0x0...
1299        l.sw    TRAMP_SLOT_2(r3),r5     // write it back
1300
1301        l.j     trampoline_out
1302        l.nop
1303
1304/* ----------------------------- */
1305
13063:      // l.jalr
1307
1308        /* 19 20 aa aa  l.movhi r9,0xaaaa
1309         * a9 29 bb bb  l.ori   r9,0xbbbb
1310         *
1311         * where 0xaaaabbbb is EEA + 0x4 shifted right 2
1312         */
1313
1314        l.addi  r6,r2,0x4               // this is 0xaaaabbbb
1315
1316                                        // l.movhi r9,0xaaaa
1317        l.ori   r5,r0,0x1920            // 0x1920 == l.movhi r9
1318        l.sh    (TRAMP_SLOT_0+0x0)(r3),r5
1319        l.srli  r5,r6,16
1320        l.sh    (TRAMP_SLOT_0+0x2)(r3),r5
1321
1322                                        // l.ori   r9,0xbbbb
1323        l.ori   r5,r0,0xa929            // 0xa929 == l.ori r9
1324        l.sh    (TRAMP_SLOT_1+0x0)(r3),r5
1325        l.andi  r5,r6,0xffff
1326        l.sh    (TRAMP_SLOT_1+0x2)(r3),r5
1327
1328        l.lhz   r5,(TRAMP_SLOT_2+0x0)(r3)       // load hi part of jump instruction
1329        l.andi  r5,r5,0x3ff             // clear out opcode part
1330        l.ori   r5,r5,0x4400            // opcode changed from l.jalr -> l.jr
1331        l.sh    (TRAMP_SLOT_2+0x0)(r3),r5 // write it back
1332
1333        /* falthrough */
1334
13351:      // l.jr
1336        l.j     trampoline_out
1337        l.nop
1338
1339/* ----------------------------- */
1340
13414:      // l.bnf
13425:      // l.bf
1343        l.slli  r6,r4,6                 // original offset shifted left 6 - 2
1344//      l.srli  r6,r6,6                 // original offset shifted right 2
1345
1346        l.slli  r4,r2,4                 // old jump position: EEA shifted left 4
1347//      l.srli  r4,r4,6                 // old jump position: shifted right 2
1348
1349        l.addi  r5,r3,0xc               // new jump position (physical)
1350        l.slli  r5,r5,4                 // new jump position: shifted left 4
1351
1352        // calculate new jump offset
1353        // new_off = old_off + (old_jump - new_jump)
1354
1355        l.add   r6,r6,r4                // (orig_off + old_jump)
1356        l.sub   r6,r6,r5                // (orig_off + old_jump) - new_jump
1357        l.srli  r6,r6,6                 // new offset shifted right 2
1358
1359        // r6 is new jump offset
1360        l.lwz   r4,(TRAMP_SLOT_2+0x0)(r3)       // load jump instruction
1361        l.srli  r4,r4,16
1362        l.andi  r4,r4,0xfc00            // get opcode part
1363        l.slli  r4,r4,16
1364        l.or    r6,r4,r6                // l.b(n)f new offset
1365        l.sw    TRAMP_SLOT_2(r3),r6     // write it back
1366
1367        /* we need to add l.j to EEA + 0x8 */
1368        tophys  (r4,r2)                 // may not be needed (due to shifts down_
1369        l.addi  r4,r4,(0x8 - 0x8)       // jump target = r2 + 0x8 (compensate for 0x8)
1370                                        // jump position = r5 + 0x8 (0x8 compensated)
1371        l.sub   r4,r4,r5                // jump offset = target - new_position + 0x8
1372
1373        l.slli  r4,r4,4                 // the amount of info in imediate of jump
1374        l.srli  r4,r4,6                 // jump instruction with offset
1375        l.sw    TRAMP_SLOT_4(r3),r4     // write it to 4th slot
1376
1377        /* fallthrough */
1378
1379trampoline_out:
1380        // set up new EPC to point to our trampoline code
1381        LOAD_SYMBOL_2_GPR(r5,_immu_trampoline)
1382        l.mtspr r0,r5,SPR_EPCR_BASE
1383
1384        // immu_trampoline is (4x) CACHE_LINE aligned
1385        // and only 6 instructions long,
1386        // so we need to invalidate only 2 lines
1387
1388        /* Establish cache block size
1389           If BS=0, 16;
1390           If BS=1, 32;
1391           r14 contain block size
1392        */
1393        l.mfspr r21,r0,SPR_ICCFGR
1394        l.andi  r21,r21,SPR_ICCFGR_CBS
1395        l.srli  r21,r21,7
1396        l.ori   r23,r0,16
1397        l.sll   r14,r23,r21
1398
1399        l.mtspr r0,r5,SPR_ICBIR
1400        l.add   r5,r5,r14
1401        l.mtspr r0,r5,SPR_ICBIR
1402
1403        l.jr    r9
1404        l.nop
1405
1406
1407/*
1408 * DSCR: prints a string referenced by r3.
1409 *
1410 * PRMS: r3             - address of the first character of null
1411 *                      terminated string to be printed
1412 *
1413 * PREQ: UART at UART_BASE_ADD has to be initialized
1414 *
1415 * POST: caller should be aware that r3, r9 are changed
1416 */
1417ENTRY(_emergency_print)
1418        EMERGENCY_PRINT_STORE_GPR4
1419        EMERGENCY_PRINT_STORE_GPR5
1420        EMERGENCY_PRINT_STORE_GPR6
1421        EMERGENCY_PRINT_STORE_GPR7
14222:
1423        l.lbz   r7,0(r3)
1424        l.sfeq  r7,r0
1425        l.bf    9f
1426        l.nop
1427
1428// putc:
1429        l.movhi r4,hi(UART_BASE_ADD)
1430
1431        l.addi  r6,r0,0x20
14321:      l.lbz   r5,5(r4)
1433        l.andi  r5,r5,0x20
1434        l.sfeq  r5,r6
1435        l.bnf   1b
1436        l.nop
1437
1438        l.sb    0(r4),r7
1439
1440        l.addi  r6,r0,0x60
14411:      l.lbz   r5,5(r4)
1442        l.andi  r5,r5,0x60
1443        l.sfeq  r5,r6
1444        l.bnf   1b
1445        l.nop
1446
1447        /* next character */
1448        l.j     2b
1449        l.addi  r3,r3,0x1
1450
14519:
1452        EMERGENCY_PRINT_LOAD_GPR7
1453        EMERGENCY_PRINT_LOAD_GPR6
1454        EMERGENCY_PRINT_LOAD_GPR5
1455        EMERGENCY_PRINT_LOAD_GPR4
1456        l.jr    r9
1457        l.nop
1458
1459ENTRY(_emergency_print_nr)
1460        EMERGENCY_PRINT_STORE_GPR4
1461        EMERGENCY_PRINT_STORE_GPR5
1462        EMERGENCY_PRINT_STORE_GPR6
1463        EMERGENCY_PRINT_STORE_GPR7
1464        EMERGENCY_PRINT_STORE_GPR8
1465
1466        l.addi  r8,r0,32                // shift register
1467
14681:      /* remove leading zeros */
1469        l.addi  r8,r8,-0x4
1470        l.srl   r7,r3,r8
1471        l.andi  r7,r7,0xf
1472
1473        /* don't skip the last zero if number == 0x0 */
1474        l.sfeqi r8,0x4
1475        l.bf    2f
1476        l.nop
1477
1478        l.sfeq  r7,r0
1479        l.bf    1b
1480        l.nop
1481
14822:
1483        l.srl   r7,r3,r8
1484
1485        l.andi  r7,r7,0xf
1486        l.sflts r8,r0
1487        l.bf    9f
1488
1489        l.sfgtui r7,0x9
1490        l.bnf   8f
1491        l.nop
1492        l.addi  r7,r7,0x27
1493
14948:
1495        l.addi  r7,r7,0x30
1496// putc:
1497        l.movhi r4,hi(UART_BASE_ADD)
1498
1499        l.addi  r6,r0,0x20
15001:      l.lbz   r5,5(r4)
1501        l.andi  r5,r5,0x20
1502        l.sfeq  r5,r6
1503        l.bnf   1b
1504        l.nop
1505
1506        l.sb    0(r4),r7
1507
1508        l.addi  r6,r0,0x60
15091:      l.lbz   r5,5(r4)
1510        l.andi  r5,r5,0x60
1511        l.sfeq  r5,r6
1512        l.bnf   1b
1513        l.nop
1514
1515        /* next character */
1516        l.j     2b
1517        l.addi  r8,r8,-0x4
1518
15199:
1520        EMERGENCY_PRINT_LOAD_GPR8
1521        EMERGENCY_PRINT_LOAD_GPR7
1522        EMERGENCY_PRINT_LOAD_GPR6
1523        EMERGENCY_PRINT_LOAD_GPR5
1524        EMERGENCY_PRINT_LOAD_GPR4
1525        l.jr    r9
1526        l.nop
1527
1528
1529/*
1530 * This should be used for debugging only.
1531 * It messes up the Linux early serial output
1532 * somehow, so use it sparingly and essentially
1533 * only if you need to debug something that goes wrong
1534 * before Linux gets the early serial going.
1535 *
1536 * Furthermore, you'll have to make sure you set the
1537 * UART_DEVISOR correctly according to the system
1538 * clock rate.
1539 *
1540 *
1541 */
1542
1543
1544
1545#define SYS_CLK            20000000
1546//#define SYS_CLK            1843200
1547#define OR32_CONSOLE_BAUD  115200
1548#define UART_DIVISOR       SYS_CLK/(16*OR32_CONSOLE_BAUD)
1549
1550ENTRY(_early_uart_init)
1551        l.movhi r3,hi(UART_BASE_ADD)
1552
1553        l.addi  r4,r0,0x7
1554        l.sb    0x2(r3),r4
1555
1556        l.addi  r4,r0,0x0
1557        l.sb    0x1(r3),r4
1558
1559        l.addi  r4,r0,0x3
1560        l.sb    0x3(r3),r4
1561
1562        l.lbz   r5,3(r3)
1563        l.ori   r4,r5,0x80
1564        l.sb    0x3(r3),r4
1565        l.addi  r4,r0,((UART_DIVISOR>>8) & 0x000000ff)
1566        l.sb    UART_DLM(r3),r4
1567        l.addi  r4,r0,((UART_DIVISOR) & 0x000000ff)
1568        l.sb    UART_DLL(r3),r4
1569        l.sb    0x3(r3),r5
1570
1571        l.jr    r9
1572        l.nop
1573
1574_string_copying_linux:
1575        .string "\n\n\n\n\n\rCopying Linux... \0"
1576
1577_string_ok_booting:
1578        .string "Ok, booting the kernel.\n\r\0"
1579
1580_string_unhandled_exception:
1581        .string "\n\rRunarunaround: Unhandled exception 0x\0"
1582
1583_string_epc_prefix:
1584        .string ": EPC=0x\0"
1585
1586_string_nl:
1587        .string "\n\r\0"
1588
1589        .global _string_esr_irq_bug
1590_string_esr_irq_bug:
1591        .string "\n\rESR external interrupt bug, for details look into entry.S\n\r\0"
1592
1593
1594
1595/* ========================================[ page aligned structures ]=== */
1596
1597/*
1598 * .data section should be page aligned
1599 *      (look into arch/or32/kernel/vmlinux.lds)
1600 */
1601        .section .data,"aw"
1602        .align  8192
1603        .global  empty_zero_page
1604empty_zero_page:
1605        .space  8192
1606
1607        .global  swapper_pg_dir
1608swapper_pg_dir:
1609        .space  8192
1610
1611        .global _unhandled_stack
1612_unhandled_stack:
1613        .space  8192
1614_unhandled_stack_top:
1615
1616/* ============================================================[ EOF ]=== */
1617