arch/openrisc/kernel/head.S

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * OpenRISC head.S
   4  *
   5  * Linux architectural port borrowing liberally from similar works of
   6  * others.  All original copyrights apply as per the original source
   7  * declaration.
   8  *
   9  * Modifications for the OpenRISC architecture:
  10  * Copyright (C) 2003 Matjaz Breskvar <[email protected]>
  11  * Copyright (C) 2010-2011 Jonas Bonn <[email protected]>
  12  */
  13
  14 #include <linux/linkage.h>
  15 #include <linux/threads.h>
  16 #include <linux/errno.h>
  17 #include <linux/init.h>
  18 #include <linux/serial_reg.h>
  19 #include <linux/pgtable.h>
  20 #include <asm/processor.h>
  21 #include <asm/page.h>
  22 #include <asm/mmu.h>
  23 #include <asm/thread_info.h>
  24 #include <asm/cache.h>
  25 #include <asm/spr_defs.h>
  26 #include <asm/asm-offsets.h>
  27 #include <linux/of_fdt.h>
  28
  29 #define tophys(rd,rs)                                           \
  30         l.movhi rd,hi(-KERNELBASE)                              ;\
  31         l.add   rd,rd,rs
  32
  33 #define CLEAR_GPR(gpr)                                          \
  34         l.movhi gpr,0x0
  35
  36 #define LOAD_SYMBOL_2_GPR(gpr,symbol)                           \
  37         l.movhi gpr,hi(symbol)                                  ;\
  38         l.ori   gpr,gpr,lo(symbol)
  39
  40
  41 #define UART_BASE_ADD      0x90000000
  42
  43 #define EXCEPTION_SR  (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_SM)
  44 #define SYSCALL_SR  (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_IEE | SPR_SR_TEE | SPR_SR_SM)
  45
  46 /* ============================================[ tmp store locations ]=== */
  47
  48 #define SPR_SHADOW_GPR(x)       ((x) + SPR_GPR_BASE + 32)
  49
  50 /*
  51  * emergency_print temporary stores
  52  */
  53 #ifdef CONFIG_OPENRISC_HAVE_SHADOW_GPRS
  54 #define EMERGENCY_PRINT_STORE_GPR4      l.mtspr r0,r4,SPR_SHADOW_GPR(14)
  55 #define EMERGENCY_PRINT_LOAD_GPR4       l.mfspr r4,r0,SPR_SHADOW_GPR(14)
  56
  57 #define EMERGENCY_PRINT_STORE_GPR5      l.mtspr r0,r5,SPR_SHADOW_GPR(15)
  58 #define EMERGENCY_PRINT_LOAD_GPR5       l.mfspr r5,r0,SPR_SHADOW_GPR(15)
  59
  60 #define EMERGENCY_PRINT_STORE_GPR6      l.mtspr r0,r6,SPR_SHADOW_GPR(16)
  61 #define EMERGENCY_PRINT_LOAD_GPR6       l.mfspr r6,r0,SPR_SHADOW_GPR(16)
  62
  63 #define EMERGENCY_PRINT_STORE_GPR7      l.mtspr r0,r7,SPR_SHADOW_GPR(7)
  64 #define EMERGENCY_PRINT_LOAD_GPR7       l.mfspr r7,r0,SPR_SHADOW_GPR(7)
  65
  66 #define EMERGENCY_PRINT_STORE_GPR8      l.mtspr r0,r8,SPR_SHADOW_GPR(8)
  67 #define EMERGENCY_PRINT_LOAD_GPR8       l.mfspr r8,r0,SPR_SHADOW_GPR(8)
  68
  69 #define EMERGENCY_PRINT_STORE_GPR9      l.mtspr r0,r9,SPR_SHADOW_GPR(9)
  70 #define EMERGENCY_PRINT_LOAD_GPR9       l.mfspr r9,r0,SPR_SHADOW_GPR(9)
  71
  72 #else /* !CONFIG_OPENRISC_HAVE_SHADOW_GPRS */
  73 #define EMERGENCY_PRINT_STORE_GPR4      l.sw    0x20(r0),r4
  74 #define EMERGENCY_PRINT_LOAD_GPR4       l.lwz   r4,0x20(r0)
  75
  76 #define EMERGENCY_PRINT_STORE_GPR5      l.sw    0x24(r0),r5
  77 #define EMERGENCY_PRINT_LOAD_GPR5       l.lwz   r5,0x24(r0)
  78
  79 #define EMERGENCY_PRINT_STORE_GPR6      l.sw    0x28(r0),r6
  80 #define EMERGENCY_PRINT_LOAD_GPR6       l.lwz   r6,0x28(r0)
  81
  82 #define EMERGENCY_PRINT_STORE_GPR7      l.sw    0x2c(r0),r7
  83 #define EMERGENCY_PRINT_LOAD_GPR7       l.lwz   r7,0x2c(r0)
  84
  85 #define EMERGENCY_PRINT_STORE_GPR8      l.sw    0x30(r0),r8
  86 #define EMERGENCY_PRINT_LOAD_GPR8       l.lwz   r8,0x30(r0)
  87
  88 #define EMERGENCY_PRINT_STORE_GPR9      l.sw    0x34(r0),r9
  89 #define EMERGENCY_PRINT_LOAD_GPR9       l.lwz   r9,0x34(r0)
  90
  91 #endif
  92
  93 /*
  94  * TLB miss handlers temorary stores
  95  */
  96 #ifdef CONFIG_OPENRISC_HAVE_SHADOW_GPRS
  97 #define EXCEPTION_STORE_GPR2            l.mtspr r0,r2,SPR_SHADOW_GPR(2)
  98 #define EXCEPTION_LOAD_GPR2             l.mfspr r2,r0,SPR_SHADOW_GPR(2)
  99
 100 #define EXCEPTION_STORE_GPR3            l.mtspr r0,r3,SPR_SHADOW_GPR(3)
 101 #define EXCEPTION_LOAD_GPR3             l.mfspr r3,r0,SPR_SHADOW_GPR(3)
 102
 103 #define EXCEPTION_STORE_GPR4            l.mtspr r0,r4,SPR_SHADOW_GPR(4)
 104 #define EXCEPTION_LOAD_GPR4             l.mfspr r4,r0,SPR_SHADOW_GPR(4)
 105
 106 #define EXCEPTION_STORE_GPR5            l.mtspr r0,r5,SPR_SHADOW_GPR(5)
 107 #define EXCEPTION_LOAD_GPR5             l.mfspr r5,r0,SPR_SHADOW_GPR(5)
 108
 109 #define EXCEPTION_STORE_GPR6            l.mtspr r0,r6,SPR_SHADOW_GPR(6)
 110 #define EXCEPTION_LOAD_GPR6             l.mfspr r6,r0,SPR_SHADOW_GPR(6)
 111
 112 #else /* !CONFIG_OPENRISC_HAVE_SHADOW_GPRS */
 113 #define EXCEPTION_STORE_GPR2            l.sw    0x64(r0),r2
 114 #define EXCEPTION_LOAD_GPR2             l.lwz   r2,0x64(r0)
 115
 116 #define EXCEPTION_STORE_GPR3            l.sw    0x68(r0),r3
 117 #define EXCEPTION_LOAD_GPR3             l.lwz   r3,0x68(r0)
 118
 119 #define EXCEPTION_STORE_GPR4            l.sw    0x6c(r0),r4
 120 #define EXCEPTION_LOAD_GPR4             l.lwz   r4,0x6c(r0)
 121
 122 #define EXCEPTION_STORE_GPR5            l.sw    0x70(r0),r5
 123 #define EXCEPTION_LOAD_GPR5             l.lwz   r5,0x70(r0)
 124
 125 #define EXCEPTION_STORE_GPR6            l.sw    0x74(r0),r6
 126 #define EXCEPTION_LOAD_GPR6             l.lwz   r6,0x74(r0)
 127
 128 #endif
 129
 130 /*
 131  * EXCEPTION_HANDLE temporary stores
 132  */
 133
 134 #ifdef CONFIG_OPENRISC_HAVE_SHADOW_GPRS
 135 #define EXCEPTION_T_STORE_GPR30         l.mtspr r0,r30,SPR_SHADOW_GPR(30)
 136 #define EXCEPTION_T_LOAD_GPR30(reg)     l.mfspr reg,r0,SPR_SHADOW_GPR(30)
 137
 138 #define EXCEPTION_T_STORE_GPR10         l.mtspr r0,r10,SPR_SHADOW_GPR(10)
 139 #define EXCEPTION_T_LOAD_GPR10(reg)     l.mfspr reg,r0,SPR_SHADOW_GPR(10)
 140
 141 #define EXCEPTION_T_STORE_SP            l.mtspr r0,r1,SPR_SHADOW_GPR(1)
 142 #define EXCEPTION_T_LOAD_SP(reg)        l.mfspr reg,r0,SPR_SHADOW_GPR(1)
 143
 144 #else /* !CONFIG_OPENRISC_HAVE_SHADOW_GPRS */
 145 #define EXCEPTION_T_STORE_GPR30         l.sw    0x78(r0),r30
 146 #define EXCEPTION_T_LOAD_GPR30(reg)     l.lwz   reg,0x78(r0)
 147
 148 #define EXCEPTION_T_STORE_GPR10         l.sw    0x7c(r0),r10
 149 #define EXCEPTION_T_LOAD_GPR10(reg)     l.lwz   reg,0x7c(r0)
 150
 151 #define EXCEPTION_T_STORE_SP            l.sw    0x80(r0),r1
 152 #define EXCEPTION_T_LOAD_SP(reg)        l.lwz   reg,0x80(r0)
 153 #endif
 154
 155 /* =========================================================[ macros ]=== */
 156
 157 #ifdef CONFIG_SMP
 158 #define GET_CURRENT_PGD(reg,t1)                                 \
 159         LOAD_SYMBOL_2_GPR(reg,current_pgd)                      ;\
 160         l.mfspr t1,r0,SPR_COREID                                ;\
 161         l.slli  t1,t1,2                                         ;\
 162         l.add   reg,reg,t1                                      ;\
 163         tophys  (t1,reg)                                        ;\
 164         l.lwz   reg,0(t1)
 165 #else
 166 #define GET_CURRENT_PGD(reg,t1)                                 \
 167         LOAD_SYMBOL_2_GPR(reg,current_pgd)                      ;\
 168         tophys  (t1,reg)                                        ;\
 169         l.lwz   reg,0(t1)
 170 #endif
 171
 172 /* Load r10 from current_thread_info_set - clobbers r1 and r30 */
 173 #ifdef CONFIG_SMP
 174 #define GET_CURRENT_THREAD_INFO                                 \
 175         LOAD_SYMBOL_2_GPR(r1,current_thread_info_set)           ;\
 176         tophys  (r30,r1)                                        ;\
 177         l.mfspr r10,r0,SPR_COREID                               ;\
 178         l.slli  r10,r10,2                                       ;\
 179         l.add   r30,r30,r10                                     ;\
 180         /* r10: current_thread_info  */                         ;\
 181         l.lwz   r10,0(r30)
 182 #else
 183 #define GET_CURRENT_THREAD_INFO                                 \
 184         LOAD_SYMBOL_2_GPR(r1,current_thread_info_set)           ;\
 185         tophys  (r30,r1)                                        ;\
 186         /* r10: current_thread_info  */                         ;\
 187         l.lwz   r10,0(r30)
 188 #endif
 189
 190 /*
 191  * DSCR: this is a common hook for handling exceptions. it will save
 192  *       the needed registers, set up stack and pointer to current
 193  *       then jump to the handler while enabling MMU
 194  *
 195  * PRMS: handler        - a function to jump to. it has to save the
 196  *                      remaining registers to kernel stack, call
 197  *                      appropriate arch-independant exception handler
 198  *                      and finaly jump to ret_from_except
 199  *
 200  * PREQ: unchanged state from the time exception happened
 201  *
 202  * POST: SAVED the following registers original value
 203  *             to the new created exception frame pointed to by r1
 204  *
 205  *       r1  - ksp      pointing to the new (exception) frame
 206  *       r4  - EEAR     exception EA
 207  *       r10 - current  pointing to current_thread_info struct
 208  *       r12 - syscall  0, since we didn't come from syscall
 209  *       r30 - handler  address of the handler we'll jump to
 210  *
 211  *       handler has to save remaining registers to the exception
 212  *       ksp frame *before* tainting them!
 213  *
 214  * NOTE: this function is not reentrant per se. reentrancy is guaranteed
 215  *       by processor disabling all exceptions/interrupts when exception
 216  *       accours.
 217  *
 218  * OPTM: no need to make it so wasteful to extract ksp when in user mode
 219  */
 220
 221 #define EXCEPTION_HANDLE(handler)                               \
 222         EXCEPTION_T_STORE_GPR30                                 ;\
 223         l.mfspr r30,r0,SPR_ESR_BASE                             ;\
 224         l.andi  r30,r30,SPR_SR_SM                               ;\
 225         l.sfeqi r30,0                                           ;\
 226         EXCEPTION_T_STORE_GPR10                                 ;\
 227         l.bnf   2f                            /* kernel_mode */ ;\
 228          EXCEPTION_T_STORE_SP                 /* delay slot */  ;\
 229 1: /* user_mode:   */                                           ;\
 230         GET_CURRENT_THREAD_INFO                                 ;\
 231         tophys  (r30,r10)                                       ;\
 232         l.lwz   r1,(TI_KSP)(r30)                                ;\
 233         /* fall through */                                      ;\
 234 2: /* kernel_mode: */                                           ;\
 235         /* create new stack frame, save only needed gprs */     ;\
 236         /* r1: KSP, r10: current, r4: EEAR, r31: __pa(KSP) */   ;\
 237         /* r12: temp, syscall indicator */                      ;\
 238         l.addi  r1,r1,-(INT_FRAME_SIZE)                         ;\
 239         /* r1 is KSP, r30 is __pa(KSP) */                       ;\
 240         tophys  (r30,r1)                                        ;\
 241         l.sw    PT_GPR12(r30),r12                               ;\
 242         /* r4 use for tmp before EA */                          ;\
 243         l.mfspr r12,r0,SPR_EPCR_BASE                            ;\
 244         l.sw    PT_PC(r30),r12                                  ;\
 245         l.mfspr r12,r0,SPR_ESR_BASE                             ;\
 246         l.sw    PT_SR(r30),r12                                  ;\
 247         /* save r30 */                                          ;\
 248         EXCEPTION_T_LOAD_GPR30(r12)                             ;\
 249         l.sw    PT_GPR30(r30),r12                               ;\
 250         /* save r10 as was prior to exception */                ;\
 251         EXCEPTION_T_LOAD_GPR10(r12)                             ;\
 252         l.sw    PT_GPR10(r30),r12                               ;\
 253         /* save PT_SP as was prior to exception */              ;\
 254         EXCEPTION_T_LOAD_SP(r12)                                ;\
 255         l.sw    PT_SP(r30),r12                                  ;\
 256         /* save exception r4, set r4 = EA */                    ;\
 257         l.sw    PT_GPR4(r30),r4                                 ;\
 258         l.mfspr r4,r0,SPR_EEAR_BASE                             ;\
 259         /* r12 == 1 if we come from syscall */                  ;\
 260         CLEAR_GPR(r12)                                          ;\
 261         /* ----- turn on MMU ----- */                           ;\
 262         /* Carry DSX into exception SR */                       ;\
 263         l.mfspr r30,r0,SPR_SR                                   ;\
 264         l.andi  r30,r30,SPR_SR_DSX                              ;\
 265         l.ori   r30,r30,(EXCEPTION_SR)                          ;\
 266         l.mtspr r0,r30,SPR_ESR_BASE                             ;\
 267         /* r30: EA address of handler */                        ;\
 268         LOAD_SYMBOL_2_GPR(r30,handler)                          ;\
 269         l.mtspr r0,r30,SPR_EPCR_BASE                            ;\
 270         l.rfe
 271
 272 /*
 273  * this doesn't work
 274  *
 275  *
 276  * #ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION
 277  * #define UNHANDLED_EXCEPTION(handler)                         \
 278  *      l.ori   r3,r0,0x1                                       ;\
 279  *      l.mtspr r0,r3,SPR_SR                                    ;\
 280  *      l.movhi r3,hi(0xf0000100)                               ;\
 281  *      l.ori   r3,r3,lo(0xf0000100)                            ;\
 282  *      l.jr    r3                                              ;\
 283  *      l.nop   1
 284  *
 285  * #endif
 286  */
 287
 288 /* DSCR: this is the same as EXCEPTION_HANDLE(), we are just
 289  *       a bit more carefull (if we have a PT_SP or current pointer
 290  *       corruption) and set them up from 'current_set'
 291  *
 292  */
 293 #define UNHANDLED_EXCEPTION(handler)                            \
 294         EXCEPTION_T_STORE_GPR30                                 ;\
 295         EXCEPTION_T_STORE_GPR10                                 ;\
 296         EXCEPTION_T_STORE_SP                                    ;\
 297         /* temporary store r3, r9 into r1, r10 */               ;\
 298         l.addi  r1,r3,0x0                                       ;\
 299         l.addi  r10,r9,0x0                                      ;\
 300         LOAD_SYMBOL_2_GPR(r9,_string_unhandled_exception)       ;\
 301         tophys  (r3,r9)                                         ;\
 302         l.jal   _emergency_print                                ;\
 303          l.nop                                                  ;\
 304         l.mfspr r3,r0,SPR_NPC                                   ;\
 305         l.jal   _emergency_print_nr                             ;\
 306          l.andi r3,r3,0x1f00                                    ;\
 307         LOAD_SYMBOL_2_GPR(r9,_string_epc_prefix)                ;\
 308         tophys  (r3,r9)                                         ;\
 309         l.jal   _emergency_print                                ;\
 310          l.nop                                                  ;\
 311         l.jal   _emergency_print_nr                             ;\
 312          l.mfspr r3,r0,SPR_EPCR_BASE                            ;\
 313         LOAD_SYMBOL_2_GPR(r9,_string_nl)                        ;\
 314         tophys  (r3,r9)                                         ;\
 315         l.jal   _emergency_print                                ;\
 316          l.nop                                                  ;\
 317         /* end of printing */                                   ;\
 318         l.addi  r3,r1,0x0                                       ;\
 319         l.addi  r9,r10,0x0                                      ;\
 320         /* extract current, ksp from current_set */             ;\
 321         LOAD_SYMBOL_2_GPR(r1,_unhandled_stack_top)              ;\
 322         LOAD_SYMBOL_2_GPR(r10,init_thread_union)                ;\
 323         /* create new stack frame, save only needed gprs */     ;\
 324         /* r1: KSP, r10: current, r31: __pa(KSP) */             ;\
 325         /* r12: temp, syscall indicator, r13 temp */            ;\
 326         l.addi  r1,r1,-(INT_FRAME_SIZE)                         ;\
 327         /* r1 is KSP, r30 is __pa(KSP) */                       ;\
 328         tophys  (r30,r1)                                        ;\
 329         l.sw    PT_GPR12(r30),r12                               ;\
 330         l.mfspr r12,r0,SPR_EPCR_BASE                            ;\
 331         l.sw    PT_PC(r30),r12                                  ;\
 332         l.mfspr r12,r0,SPR_ESR_BASE                             ;\
 333         l.sw    PT_SR(r30),r12                                  ;\
 334         /* save r31 */                                          ;\
 335         EXCEPTION_T_LOAD_GPR30(r12)                             ;\
 336         l.sw    PT_GPR30(r30),r12                               ;\
 337         /* save r10 as was prior to exception */                ;\
 338         EXCEPTION_T_LOAD_GPR10(r12)                             ;\
 339         l.sw    PT_GPR10(r30),r12                               ;\
 340         /* save PT_SP as was prior to exception */              ;\
 341         EXCEPTION_T_LOAD_SP(r12)                                ;\
 342         l.sw    PT_SP(r30),r12                                  ;\
 343         l.sw    PT_GPR13(r30),r13                               ;\
 344         /* --> */                                               ;\
 345         /* save exception r4, set r4 = EA */                    ;\
 346         l.sw    PT_GPR4(r30),r4                                 ;\
 347         l.mfspr r4,r0,SPR_EEAR_BASE                             ;\
 348         /* r12 == 1 if we come from syscall */                  ;\
 349         CLEAR_GPR(r12)                                          ;\
 350         /* ----- play a MMU trick ----- */                      ;\
 351         l.ori   r30,r0,(EXCEPTION_SR)                           ;\
 352         l.mtspr r0,r30,SPR_ESR_BASE                             ;\
 353         /* r31: EA address of handler */                        ;\
 354         LOAD_SYMBOL_2_GPR(r30,handler)                          ;\
 355         l.mtspr r0,r30,SPR_EPCR_BASE                            ;\
 356         l.rfe
 357
 358 /* =====================================================[ exceptions] === */
 359
 360         __HEAD
 361
 362 /* ---[ 0x100: RESET exception ]----------------------------------------- */
 363     .org 0x100
 364         /* Jump to .init code at _start which lives in the .head section
 365          * and will be discarded after boot.
 366          */
 367         LOAD_SYMBOL_2_GPR(r15, _start)
 368         tophys  (r13,r15)                       /* MMU disabled */
 369         l.jr    r13
 370          l.nop
 371
 372 /* ---[ 0x200: BUS exception ]------------------------------------------- */
 373     .org 0x200
 374 _dispatch_bus_fault:
 375         EXCEPTION_HANDLE(_bus_fault_handler)
 376
 377 /* ---[ 0x300: Data Page Fault exception ]------------------------------- */
 378     .org 0x300
 379 _dispatch_do_dpage_fault:
 380 //      totaly disable timer interrupt
 381 //      l.mtspr r0,r0,SPR_TTMR
 382 //      DEBUG_TLB_PROBE(0x300)
 383 //      EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x300)
 384         EXCEPTION_HANDLE(_data_page_fault_handler)
 385
 386 /* ---[ 0x400: Insn Page Fault exception ]------------------------------- */
 387     .org 0x400
 388 _dispatch_do_ipage_fault:
 389 //      totaly disable timer interrupt
 390 //      l.mtspr r0,r0,SPR_TTMR
 391 //      DEBUG_TLB_PROBE(0x400)
 392 //      EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x400)
 393         EXCEPTION_HANDLE(_insn_page_fault_handler)
 394
 395 /* ---[ 0x500: Timer exception ]----------------------------------------- */
 396     .org 0x500
 397         EXCEPTION_HANDLE(_timer_handler)
 398
 399 /* ---[ 0x600: Alignment exception ]------------------------------------- */
 400     .org 0x600
 401         EXCEPTION_HANDLE(_alignment_handler)
 402
 403 /* ---[ 0x700: Illegal insn exception ]---------------------------------- */
 404     .org 0x700
 405         EXCEPTION_HANDLE(_illegal_instruction_handler)
 406
 407 /* ---[ 0x800: External interrupt exception ]---------------------------- */
 408     .org 0x800
 409         EXCEPTION_HANDLE(_external_irq_handler)
 410
 411 /* ---[ 0x900: DTLB miss exception ]------------------------------------- */
 412     .org 0x900
 413         l.j     boot_dtlb_miss_handler
 414         l.nop
 415
 416 /* ---[ 0xa00: ITLB miss exception ]------------------------------------- */
 417     .org 0xa00
 418         l.j     boot_itlb_miss_handler
 419         l.nop
 420
 421 /* ---[ 0xb00: Range exception ]----------------------------------------- */
 422     .org 0xb00
 423         UNHANDLED_EXCEPTION(_vector_0xb00)
 424
 425 /* ---[ 0xc00: Syscall exception ]--------------------------------------- */
 426     .org 0xc00
 427         EXCEPTION_HANDLE(_sys_call_handler)
 428
 429 /* ---[ 0xd00: Floating point exception ]-------------------------------- */
 430     .org 0xd00
 431         EXCEPTION_HANDLE(_fpe_trap_handler)
 432
 433 /* ---[ 0xe00: Trap exception ]------------------------------------------ */
 434     .org 0xe00
 435 //      UNHANDLED_EXCEPTION(_vector_0xe00)
 436         EXCEPTION_HANDLE(_trap_handler)
 437
 438 /* ---[ 0xf00: Reserved exception ]-------------------------------------- */
 439     .org 0xf00
 440         UNHANDLED_EXCEPTION(_vector_0xf00)
 441
 442 /* ---[ 0x1000: Reserved exception ]------------------------------------- */
 443     .org 0x1000
 444         UNHANDLED_EXCEPTION(_vector_0x1000)
 445
 446 /* ---[ 0x1100: Reserved exception ]------------------------------------- */
 447     .org 0x1100
 448         UNHANDLED_EXCEPTION(_vector_0x1100)
 449
 450 /* ---[ 0x1200: Reserved exception ]------------------------------------- */
 451     .org 0x1200
 452         UNHANDLED_EXCEPTION(_vector_0x1200)
 453
 454 /* ---[ 0x1300: Reserved exception ]------------------------------------- */
 455     .org 0x1300
 456         UNHANDLED_EXCEPTION(_vector_0x1300)
 457
 458 /* ---[ 0x1400: Reserved exception ]------------------------------------- */
 459     .org 0x1400
 460         UNHANDLED_EXCEPTION(_vector_0x1400)
 461
 462 /* ---[ 0x1500: Reserved exception ]------------------------------------- */
 463     .org 0x1500
 464         UNHANDLED_EXCEPTION(_vector_0x1500)
 465
 466 /* ---[ 0x1600: Reserved exception ]------------------------------------- */
 467     .org 0x1600
 468         UNHANDLED_EXCEPTION(_vector_0x1600)
 469
 470 /* ---[ 0x1700: Reserved exception ]------------------------------------- */
 471     .org 0x1700
 472         UNHANDLED_EXCEPTION(_vector_0x1700)
 473
 474 /* ---[ 0x1800: Reserved exception ]------------------------------------- */
 475     .org 0x1800
 476         UNHANDLED_EXCEPTION(_vector_0x1800)
 477
 478 /* ---[ 0x1900: Reserved exception ]------------------------------------- */
 479     .org 0x1900
 480         UNHANDLED_EXCEPTION(_vector_0x1900)
 481
 482 /* ---[ 0x1a00: Reserved exception ]------------------------------------- */
 483     .org 0x1a00
 484         UNHANDLED_EXCEPTION(_vector_0x1a00)
 485
 486 /* ---[ 0x1b00: Reserved exception ]------------------------------------- */
 487     .org 0x1b00
 488         UNHANDLED_EXCEPTION(_vector_0x1b00)
 489
 490 /* ---[ 0x1c00: Reserved exception ]------------------------------------- */
 491     .org 0x1c00
 492         UNHANDLED_EXCEPTION(_vector_0x1c00)
 493
 494 /* ---[ 0x1d00: Reserved exception ]------------------------------------- */
 495     .org 0x1d00
 496         UNHANDLED_EXCEPTION(_vector_0x1d00)
 497
 498 /* ---[ 0x1e00: Reserved exception ]------------------------------------- */
 499     .org 0x1e00
 500         UNHANDLED_EXCEPTION(_vector_0x1e00)
 501
 502 /* ---[ 0x1f00: Reserved exception ]------------------------------------- */
 503     .org 0x1f00
 504         UNHANDLED_EXCEPTION(_vector_0x1f00)
 505
 506     .org 0x2000
 507 /* ===================================================[ kernel start ]=== */
 508
 509 /*    .text*/
 510
 511 /* This early stuff belongs in the .init.text section, but some of the functions below definitely
 512  * don't... */
 513
 514         __INIT
 515         .global _start
 516 _start:
 517         /* Init r0 to zero as per spec */
 518         CLEAR_GPR(r0)
 519
 520         /* save kernel parameters */
 521         l.or    r25,r0,r3       /* pointer to fdt */
 522
 523         /*
 524          * ensure a deterministic start
 525          */
 526
 527         l.ori   r3,r0,0x1
 528         l.mtspr r0,r3,SPR_SR
 529
 530         /*
 531          * Start the TTCR as early as possible, so that the RNG can make use of
 532          * measurements of boot time from the earliest opportunity. Especially
 533          * important is that the TTCR does not return zero by the time we reach
 534          * random_init().
 535          */
 536         l.movhi r3,hi(SPR_TTMR_CR)
 537         l.mtspr r0,r3,SPR_TTMR
 538
 539         CLEAR_GPR(r1)
 540         CLEAR_GPR(r2)
 541         CLEAR_GPR(r3)
 542         CLEAR_GPR(r4)
 543         CLEAR_GPR(r5)
 544         CLEAR_GPR(r6)
 545         CLEAR_GPR(r7)
 546         CLEAR_GPR(r8)
 547         CLEAR_GPR(r9)
 548         CLEAR_GPR(r10)
 549         CLEAR_GPR(r11)
 550         CLEAR_GPR(r12)
 551         CLEAR_GPR(r13)
 552         CLEAR_GPR(r14)
 553         CLEAR_GPR(r15)
 554         CLEAR_GPR(r16)
 555         CLEAR_GPR(r17)
 556         CLEAR_GPR(r18)
 557         CLEAR_GPR(r19)
 558         CLEAR_GPR(r20)
 559         CLEAR_GPR(r21)
 560         CLEAR_GPR(r22)
 561         CLEAR_GPR(r23)
 562         CLEAR_GPR(r24)
 563         CLEAR_GPR(r26)
 564         CLEAR_GPR(r27)
 565         CLEAR_GPR(r28)
 566         CLEAR_GPR(r29)
 567         CLEAR_GPR(r30)
 568         CLEAR_GPR(r31)
 569
 570 #ifdef CONFIG_SMP
 571         l.mfspr r26,r0,SPR_COREID
 572         l.sfeq  r26,r0
 573         l.bnf   secondary_wait
 574          l.nop
 575 #endif
 576         /*
 577          * set up initial ksp and current
 578          */
 579         /* setup kernel stack */
 580         LOAD_SYMBOL_2_GPR(r1,init_thread_union + THREAD_SIZE)
 581         LOAD_SYMBOL_2_GPR(r10,init_thread_union)        // setup current
 582         tophys  (r31,r10)
 583         l.sw    TI_KSP(r31), r1
 584
 585         l.ori   r4,r0,0x0
 586
 587
 588         /*
 589          * .data contains initialized data,
 590          * .bss contains uninitialized data - clear it up
 591          */
 592 clear_bss:
 593         LOAD_SYMBOL_2_GPR(r24, __bss_start)
 594         LOAD_SYMBOL_2_GPR(r26, _end)
 595         tophys(r28,r24)
 596         tophys(r30,r26)
 597         CLEAR_GPR(r24)
 598         CLEAR_GPR(r26)
 599 1:
 600         l.sw    (0)(r28),r0
 601         l.sfltu r28,r30
 602         l.bf    1b
 603         l.addi  r28,r28,4
 604
 605 enable_ic:
 606         l.jal   _ic_enable
 607          l.nop
 608
 609 enable_dc:
 610         l.jal   _dc_enable
 611          l.nop
 612
 613 flush_tlb:
 614         l.jal   _flush_tlb
 615          l.nop
 616
 617 /* The MMU needs to be enabled before or1k_early_setup is called */
 618
 619 enable_mmu:
 620         /*
 621          * enable dmmu & immu
 622          * SR[5] = 0, SR[6] = 0, 6th and 7th bit of SR set to 0
 623          */
 624         l.mfspr r30,r0,SPR_SR
 625         l.movhi r28,hi(SPR_SR_DME | SPR_SR_IME)
 626         l.ori   r28,r28,lo(SPR_SR_DME | SPR_SR_IME)
 627         l.or    r30,r30,r28
 628         l.mtspr r0,r30,SPR_SR
 629         l.nop
 630         l.nop
 631         l.nop
 632         l.nop
 633         l.nop
 634         l.nop
 635         l.nop
 636         l.nop
 637         l.nop
 638         l.nop
 639         l.nop
 640         l.nop
 641         l.nop
 642         l.nop
 643         l.nop
 644         l.nop
 645
 646         // reset the simulation counters
 647         l.nop 5
 648
 649         /* check fdt header magic word */
 650         l.lwz   r3,0(r25)       /* load magic from fdt into r3 */
 651         l.movhi r4,hi(OF_DT_HEADER)
 652         l.ori   r4,r4,lo(OF_DT_HEADER)
 653         l.sfeq  r3,r4
 654         l.bf    _fdt_found
 655          l.nop
 656         /* magic number mismatch, set fdt pointer to null */
 657         l.or    r25,r0,r0
 658 _fdt_found:
 659         /* pass fdt pointer to or1k_early_setup in r3 */
 660         l.or    r3,r0,r25
 661         LOAD_SYMBOL_2_GPR(r24, or1k_early_setup)
 662         l.jalr r24
 663          l.nop
 664
 665 clear_regs:
 666         /*
 667          * clear all GPRS to increase determinism
 668          */
 669         CLEAR_GPR(r2)
 670         CLEAR_GPR(r3)
 671         CLEAR_GPR(r4)
 672         CLEAR_GPR(r5)
 673         CLEAR_GPR(r6)
 674         CLEAR_GPR(r7)
 675         CLEAR_GPR(r8)
 676         CLEAR_GPR(r9)
 677         CLEAR_GPR(r11)
 678         CLEAR_GPR(r12)
 679         CLEAR_GPR(r13)
 680         CLEAR_GPR(r14)
 681         CLEAR_GPR(r15)
 682         CLEAR_GPR(r16)
 683         CLEAR_GPR(r17)
 684         CLEAR_GPR(r18)
 685         CLEAR_GPR(r19)
 686         CLEAR_GPR(r20)
 687         CLEAR_GPR(r21)
 688         CLEAR_GPR(r22)
 689         CLEAR_GPR(r23)
 690         CLEAR_GPR(r24)
 691         CLEAR_GPR(r25)
 692         CLEAR_GPR(r26)
 693         CLEAR_GPR(r27)
 694         CLEAR_GPR(r28)
 695         CLEAR_GPR(r29)
 696         CLEAR_GPR(r30)
 697         CLEAR_GPR(r31)
 698
 699 jump_start_kernel:
 700         /*
 701          * jump to kernel entry (start_kernel)
 702          */
 703         LOAD_SYMBOL_2_GPR(r30, start_kernel)
 704         l.jr    r30
 705          l.nop
 706
 707 _flush_tlb:
 708         /*
 709          *  I N V A L I D A T E   T L B   e n t r i e s
 710          */
 711         LOAD_SYMBOL_2_GPR(r5,SPR_DTLBMR_BASE(0))
 712         LOAD_SYMBOL_2_GPR(r6,SPR_ITLBMR_BASE(0))
 713         l.addi  r7,r0,128 /* Maximum number of sets */
 714 1:
 715         l.mtspr r5,r0,0x0
 716         l.mtspr r6,r0,0x0
 717
 718         l.addi  r5,r5,1
 719         l.addi  r6,r6,1
 720         l.sfeq  r7,r0
 721         l.bnf   1b
 722          l.addi r7,r7,-1
 723
 724         l.jr    r9
 725          l.nop
 726
 727 #ifdef CONFIG_SMP
 728 secondary_wait:
 729         /* Doze the cpu until we are asked to run */
 730         /* If we dont have power management skip doze */
 731         l.mfspr r25,r0,SPR_UPR
 732         l.andi  r25,r25,SPR_UPR_PMP
 733         l.sfeq  r25,r0
 734         l.bf    secondary_check_release
 735          l.nop
 736
 737         /* Setup special secondary exception handler */
 738         LOAD_SYMBOL_2_GPR(r3, _secondary_evbar)
 739         tophys(r25,r3)
 740         l.mtspr r0,r25,SPR_EVBAR
 741
 742         /* Enable Interrupts */
 743         l.mfspr r25,r0,SPR_SR
 744         l.ori   r25,r25,SPR_SR_IEE
 745         l.mtspr r0,r25,SPR_SR
 746
 747         /* Unmask interrupts interrupts */
 748         l.mfspr r25,r0,SPR_PICMR
 749         l.ori   r25,r25,0xffff
 750         l.mtspr r0,r25,SPR_PICMR
 751
 752         /* Doze */
 753         l.mfspr r25,r0,SPR_PMR
 754         LOAD_SYMBOL_2_GPR(r3, SPR_PMR_DME)
 755         l.or    r25,r25,r3
 756         l.mtspr r0,r25,SPR_PMR
 757
 758         /* Wakeup - Restore exception handler */
 759         l.mtspr r0,r0,SPR_EVBAR
 760
 761 secondary_check_release:
 762         /*
 763          * Check if we actually got the release signal, if not go-back to
 764          * sleep.
 765          */
 766         l.mfspr r25,r0,SPR_COREID
 767         LOAD_SYMBOL_2_GPR(r3, secondary_release)
 768         tophys(r4, r3)
 769         l.lwz   r3,0(r4)
 770         l.sfeq  r25,r3
 771         l.bnf   secondary_wait
 772          l.nop
 773         /* fall through to secondary_init */
 774
 775 secondary_init:
 776         /*
 777          * set up initial ksp and current
 778          */
 779         LOAD_SYMBOL_2_GPR(r10, secondary_thread_info)
 780         tophys  (r30,r10)
 781         l.lwz   r10,0(r30)
 782         l.addi  r1,r10,THREAD_SIZE
 783         tophys  (r30,r10)
 784         l.sw    TI_KSP(r30),r1
 785
 786         l.jal   _ic_enable
 787          l.nop
 788
 789         l.jal   _dc_enable
 790          l.nop
 791
 792         l.jal   _flush_tlb
 793          l.nop
 794
 795         /*
 796          * enable dmmu & immu
 797          */
 798         l.mfspr r30,r0,SPR_SR
 799         l.movhi r28,hi(SPR_SR_DME | SPR_SR_IME)
 800         l.ori   r28,r28,lo(SPR_SR_DME | SPR_SR_IME)
 801         l.or    r30,r30,r28
 802         /*
 803          * This is a bit tricky, we need to switch over from physical addresses
 804          * to virtual addresses on the fly.
 805          * To do that, we first set up ESR with the IME and DME bits set.
 806          * Then EPCR is set to secondary_start and then a l.rfe is issued to
 807          * "jump" to that.
 808          */
 809         l.mtspr r0,r30,SPR_ESR_BASE
 810         LOAD_SYMBOL_2_GPR(r30, secondary_start)
 811         l.mtspr r0,r30,SPR_EPCR_BASE
 812         l.rfe
 813
 814 secondary_start:
 815         LOAD_SYMBOL_2_GPR(r30, secondary_start_kernel)
 816         l.jr    r30
 817          l.nop
 818
 819 #endif
 820
 821 /* ==========================================================[ cache ]=== */
 822
 823         /* alignment here so we don't change memory offsets with
 824          * memory controller defined
 825          */
 826         .align 0x2000
 827
 828 _ic_enable:
 829         /* Check if IC present and skip enabling otherwise */
 830         l.mfspr r24,r0,SPR_UPR
 831         l.andi  r26,r24,SPR_UPR_ICP
 832         l.sfeq  r26,r0
 833         l.bf    9f
 834         l.nop
 835
 836         /* Disable IC */
 837         l.mfspr r6,r0,SPR_SR
 838         l.addi  r5,r0,-1
 839         l.xori  r5,r5,SPR_SR_ICE
 840         l.and   r5,r6,r5
 841         l.mtspr r0,r5,SPR_SR
 842
 843         /* Establish cache block size
 844            If BS=0, 16;
 845            If BS=1, 32;
 846            r14 contain block size
 847         */
 848         l.mfspr r24,r0,SPR_ICCFGR
 849         l.andi  r26,r24,SPR_ICCFGR_CBS
 850         l.srli  r28,r26,7
 851         l.ori   r30,r0,16
 852         l.sll   r14,r30,r28
 853
 854         /* Establish number of cache sets
 855            r16 contains number of cache sets
 856            r28 contains log(# of cache sets)
 857         */
 858         l.andi  r26,r24,SPR_ICCFGR_NCS
 859         l.srli  r28,r26,3
 860         l.ori   r30,r0,1
 861         l.sll   r16,r30,r28
 862
 863         /* Invalidate IC */
 864         l.addi  r6,r0,0
 865         l.sll   r5,r14,r28
 866 //        l.mul   r5,r14,r16
 867 //      l.trap  1
 868 //      l.addi  r5,r0,IC_SIZE
 869 1:
 870         l.mtspr r0,r6,SPR_ICBIR
 871         l.sfne  r6,r5
 872         l.bf    1b
 873         l.add   r6,r6,r14
 874  //       l.addi   r6,r6,IC_LINE
 875
 876         /* Enable IC */
 877         l.mfspr r6,r0,SPR_SR
 878         l.ori   r6,r6,SPR_SR_ICE
 879         l.mtspr r0,r6,SPR_SR
 880         l.nop
 881         l.nop
 882         l.nop
 883         l.nop
 884         l.nop
 885         l.nop
 886         l.nop
 887         l.nop
 888         l.nop
 889         l.nop
 890 9:
 891         l.jr    r9
 892         l.nop
 893
 894 _dc_enable:
 895         /* Check if DC present and skip enabling otherwise */
 896         l.mfspr r24,r0,SPR_UPR
 897         l.andi  r26,r24,SPR_UPR_DCP
 898         l.sfeq  r26,r0
 899         l.bf    9f
 900         l.nop
 901
 902         /* Disable DC */
 903         l.mfspr r6,r0,SPR_SR
 904         l.addi  r5,r0,-1
 905         l.xori  r5,r5,SPR_SR_DCE
 906         l.and   r5,r6,r5
 907         l.mtspr r0,r5,SPR_SR
 908
 909         /* Establish cache block size
 910            If BS=0, 16;
 911            If BS=1, 32;
 912            r14 contain block size
 913         */
 914         l.mfspr r24,r0,SPR_DCCFGR
 915         l.andi  r26,r24,SPR_DCCFGR_CBS
 916         l.srli  r28,r26,7
 917         l.ori   r30,r0,16
 918         l.sll   r14,r30,r28
 919
 920         /* Establish number of cache sets
 921            r16 contains number of cache sets
 922            r28 contains log(# of cache sets)
 923         */
 924         l.andi  r26,r24,SPR_DCCFGR_NCS
 925         l.srli  r28,r26,3
 926         l.ori   r30,r0,1
 927         l.sll   r16,r30,r28
 928
 929         /* Invalidate DC */
 930         l.addi  r6,r0,0
 931         l.sll   r5,r14,r28
 932 1:
 933         l.mtspr r0,r6,SPR_DCBIR
 934         l.sfne  r6,r5
 935         l.bf    1b
 936         l.add   r6,r6,r14
 937
 938         /* Enable DC */
 939         l.mfspr r6,r0,SPR_SR
 940         l.ori   r6,r6,SPR_SR_DCE
 941         l.mtspr r0,r6,SPR_SR
 942 9:
 943         l.jr    r9
 944         l.nop
 945
 946 /* ===============================================[ page table masks ]=== */
 947
 948 #define DTLB_UP_CONVERT_MASK  0x3fa
 949 #define ITLB_UP_CONVERT_MASK  0x3a
 950
 951 /* for SMP we'd have (this is a bit subtle, CC must be always set
 952  * for SMP, but since we have _PAGE_PRESENT bit always defined
 953  * we can just modify the mask)
 954  */
 955 #define DTLB_SMP_CONVERT_MASK  0x3fb
 956 #define ITLB_SMP_CONVERT_MASK  0x3b
 957
 958 /* ---[ boot dtlb miss handler ]----------------------------------------- */
 959
 960 boot_dtlb_miss_handler:
 961
 962 /* mask for DTLB_MR register: - (0) sets V (valid) bit,
 963  *                            - (31-12) sets bits belonging to VPN (31-12)
 964  */
 965 #define DTLB_MR_MASK 0xfffff001
 966
 967 /* mask for DTLB_TR register: - (2) sets CI (cache inhibit) bit,
 968  *                            - (4) sets A (access) bit,
 969  *                            - (5) sets D (dirty) bit,
 970  *                            - (8) sets SRE (superuser read) bit
 971  *                            - (9) sets SWE (superuser write) bit
 972  *                            - (31-12) sets bits belonging to VPN (31-12)
 973  */
 974 #define DTLB_TR_MASK 0xfffff332
 975
 976 /* These are for masking out the VPN/PPN value from the MR/TR registers...
 977  * it's not the same as the PFN */
 978 #define VPN_MASK 0xfffff000
 979 #define PPN_MASK 0xfffff000
 980
 981
 982         EXCEPTION_STORE_GPR6
 983
 984 #if 0
 985         l.mfspr r6,r0,SPR_ESR_BASE         //
 986         l.andi  r6,r6,SPR_SR_SM            // are we in kernel mode ?
 987         l.sfeqi r6,0                       // r6 == 0x1 --> SM
 988         l.bf    exit_with_no_dtranslation  //
 989         l.nop
 990 #endif
 991
 992         /* this could be optimized by moving storing of
 993          * non r6 registers here, and jumping r6 restore
 994          * if not in supervisor mode
 995          */
 996
 997         EXCEPTION_STORE_GPR2
 998         EXCEPTION_STORE_GPR3
 999         EXCEPTION_STORE_GPR4
1000         EXCEPTION_STORE_GPR5
1001
1002         l.mfspr r4,r0,SPR_EEAR_BASE        // get the offending EA
1003
1004 immediate_translation:
1005         CLEAR_GPR(r6)
1006
1007         l.srli  r3,r4,0xd                  // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
1008
1009         l.mfspr r6, r0, SPR_DMMUCFGR
1010         l.andi  r6, r6, SPR_DMMUCFGR_NTS
1011         l.srli  r6, r6, SPR_DMMUCFGR_NTS_OFF
1012         l.ori   r5, r0, 0x1
1013         l.sll   r5, r5, r6      // r5 = number DMMU sets
1014         l.addi  r6, r5, -1      // r6 = nsets mask
1015         l.and   r2, r3, r6      // r2 <- r3 % NSETS_MASK
1016
1017         l.or    r6,r6,r4                   // r6 <- r4
1018         l.ori   r6,r6,~(VPN_MASK)          // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
1019         l.movhi r5,hi(DTLB_MR_MASK)        // r5 <- ffff:0000.x000
1020         l.ori   r5,r5,lo(DTLB_MR_MASK)     // r5 <- ffff:1111.x001 - apply DTLB_MR_MASK
1021         l.and   r5,r5,r6                   // r5 <- VPN :VPN .x001 - we have DTLBMR entry
1022         l.mtspr r2,r5,SPR_DTLBMR_BASE(0)   // set DTLBMR
1023
1024         /* set up DTLB with no translation for EA <= 0xbfffffff */
1025         LOAD_SYMBOL_2_GPR(r6,0xbfffffff)
1026         l.sfgeu  r6,r4                     // flag if r6 >= r4 (if 0xbfffffff >= EA)
1027         l.bf     1f                        // goto out
1028         l.and    r3,r4,r4                  // delay slot :: 24 <- r4 (if flag==1)
1029
1030         tophys(r3,r4)                      // r3 <- PA
1031 1:
1032         l.ori   r3,r3,~(PPN_MASK)          // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
1033         l.movhi r5,hi(DTLB_TR_MASK)        // r5 <- ffff:0000.x000
1034         l.ori   r5,r5,lo(DTLB_TR_MASK)     // r5 <- ffff:1111.x330 - apply DTLB_MR_MASK
1035         l.and   r5,r5,r3                   // r5 <- PPN :PPN .x330 - we have DTLBTR entry
1036         l.mtspr r2,r5,SPR_DTLBTR_BASE(0)   // set DTLBTR
1037
1038         EXCEPTION_LOAD_GPR6
1039         EXCEPTION_LOAD_GPR5
1040         EXCEPTION_LOAD_GPR4
1041         EXCEPTION_LOAD_GPR3
1042         EXCEPTION_LOAD_GPR2
1043
1044         l.rfe                              // SR <- ESR, PC <- EPC
1045
1046 exit_with_no_dtranslation:
1047         /* EA out of memory or not in supervisor mode */
1048         EXCEPTION_LOAD_GPR6
1049         EXCEPTION_LOAD_GPR4
1050         l.j     _dispatch_bus_fault
1051
1052 /* ---[ boot itlb miss handler ]----------------------------------------- */
1053
1054 boot_itlb_miss_handler:
1055
1056 /* mask for ITLB_MR register: - sets V (valid) bit,
1057  *                            - sets bits belonging to VPN (15-12)
1058  */
1059 #define ITLB_MR_MASK 0xfffff001
1060
1061 /* mask for ITLB_TR register: - sets A (access) bit,
1062  *                            - sets SXE (superuser execute) bit
1063  *                            - sets bits belonging to VPN (15-12)
1064  */
1065 #define ITLB_TR_MASK 0xfffff050
1066
1067 /*
1068 #define VPN_MASK 0xffffe000
1069 #define PPN_MASK 0xffffe000
1070 */
1071
1072
1073
1074         EXCEPTION_STORE_GPR2
1075         EXCEPTION_STORE_GPR3
1076         EXCEPTION_STORE_GPR4
1077         EXCEPTION_STORE_GPR5
1078         EXCEPTION_STORE_GPR6
1079
1080 #if 0
1081         l.mfspr r6,r0,SPR_ESR_BASE         //
1082         l.andi  r6,r6,SPR_SR_SM            // are we in kernel mode ?
1083         l.sfeqi r6,0                       // r6 == 0x1 --> SM
1084         l.bf    exit_with_no_itranslation
1085         l.nop
1086 #endif
1087
1088
1089         l.mfspr r4,r0,SPR_EEAR_BASE        // get the offending EA
1090
1091 earlyearly:
1092         CLEAR_GPR(r6)
1093
1094         l.srli  r3,r4,0xd                  // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
1095
1096         l.mfspr r6, r0, SPR_IMMUCFGR
1097         l.andi  r6, r6, SPR_IMMUCFGR_NTS
1098         l.srli  r6, r6, SPR_IMMUCFGR_NTS_OFF
1099         l.ori   r5, r0, 0x1
1100         l.sll   r5, r5, r6      // r5 = number IMMU sets from IMMUCFGR
1101         l.addi  r6, r5, -1      // r6 = nsets mask
1102         l.and   r2, r3, r6      // r2 <- r3 % NSETS_MASK
1103
1104         l.or    r6,r6,r4                   // r6 <- r4
1105         l.ori   r6,r6,~(VPN_MASK)          // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
1106         l.movhi r5,hi(ITLB_MR_MASK)        // r5 <- ffff:0000.x000
1107         l.ori   r5,r5,lo(ITLB_MR_MASK)     // r5 <- ffff:1111.x001 - apply ITLB_MR_MASK
1108         l.and   r5,r5,r6                   // r5 <- VPN :VPN .x001 - we have ITLBMR entry
1109         l.mtspr r2,r5,SPR_ITLBMR_BASE(0)   // set ITLBMR
1110
1111         /*
1112          * set up ITLB with no translation for EA <= 0x0fffffff
1113          *
1114          * we need this for head.S mapping (EA = PA). if we move all functions
1115          * which run with mmu enabled into entry.S, we might be able to eliminate this.
1116          *
1117          */
1118         LOAD_SYMBOL_2_GPR(r6,0x0fffffff)
1119         l.sfgeu  r6,r4                     // flag if r6 >= r4 (if 0xb0ffffff >= EA)
1120         l.bf     1f                        // goto out
1121         l.and    r3,r4,r4                  // delay slot :: 24 <- r4 (if flag==1)
1122
1123         tophys(r3,r4)                      // r3 <- PA
1124 1:
1125         l.ori   r3,r3,~(PPN_MASK)          // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
1126         l.movhi r5,hi(ITLB_TR_MASK)        // r5 <- ffff:0000.x000
1127         l.ori   r5,r5,lo(ITLB_TR_MASK)     // r5 <- ffff:1111.x050 - apply ITLB_MR_MASK
1128         l.and   r5,r5,r3                   // r5 <- PPN :PPN .x050 - we have ITLBTR entry
1129         l.mtspr r2,r5,SPR_ITLBTR_BASE(0)   // set ITLBTR
1130
1131         EXCEPTION_LOAD_GPR6
1132         EXCEPTION_LOAD_GPR5
1133         EXCEPTION_LOAD_GPR4
1134         EXCEPTION_LOAD_GPR3
1135         EXCEPTION_LOAD_GPR2
1136
1137         l.rfe                              // SR <- ESR, PC <- EPC
1138
1139 exit_with_no_itranslation:
1140         EXCEPTION_LOAD_GPR4
1141         EXCEPTION_LOAD_GPR6
1142         l.j    _dispatch_bus_fault
1143         l.nop
1144
1145 /* ====================================================================== */
1146 /*
1147  * Stuff below here shouldn't go into .head section... maybe this stuff
1148  * can be moved to entry.S ???
1149  */
1150
1151 /* ==============================================[ DTLB miss handler ]=== */
1152
1153 /*
1154  * Comments:
1155  *   Exception handlers are entered with MMU off so the following handler
1156  *   needs to use physical addressing
1157  *
1158  */
1159
1160         .text
1161 ENTRY(dtlb_miss_handler)
1162         EXCEPTION_STORE_GPR2
1163         EXCEPTION_STORE_GPR3
1164         EXCEPTION_STORE_GPR4
1165         /*
1166          * get EA of the miss
1167          */
1168         l.mfspr r2,r0,SPR_EEAR_BASE
1169         /*
1170          * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
1171          */
1172         GET_CURRENT_PGD(r3,r4)          // r3 is current_pgd, r4 is temp
1173         l.srli  r4,r2,0x18              // >> PAGE_SHIFT + (PAGE_SHIFT - 2)
1174         l.slli  r4,r4,0x2               // to get address << 2
1175         l.add   r3,r4,r3                // r4 is pgd_index(daddr)
1176         /*
1177          * if (pmd_none(*pmd))
1178          *   goto pmd_none:
1179          */
1180         tophys  (r4,r3)
1181         l.lwz   r3,0x0(r4)              // get *pmd value
1182         l.sfne  r3,r0
1183         l.bnf   d_pmd_none
1184          l.addi r3,r0,0xffffe000        // PAGE_MASK
1185
1186 d_pmd_good:
1187         /*
1188          * pte = *pte_offset(pmd, daddr);
1189          */
1190         l.lwz   r4,0x0(r4)              // get **pmd value
1191         l.and   r4,r4,r3                // & PAGE_MASK
1192         l.srli  r2,r2,0xd               // >> PAGE_SHIFT, r2 == EEAR
1193         l.andi  r3,r2,0x7ff             // (1UL << PAGE_SHIFT - 2) - 1
1194         l.slli  r3,r3,0x2               // to get address << 2
1195         l.add   r3,r3,r4
1196         l.lwz   r3,0x0(r3)              // this is pte at last
1197         /*
1198          * if (!pte_present(pte))
1199          */
1200         l.andi  r4,r3,0x1
1201         l.sfne  r4,r0                   // is pte present
1202         l.bnf   d_pte_not_present
1203         l.addi  r4,r0,0xffffe3fa        // PAGE_MASK | DTLB_UP_CONVERT_MASK
1204         /*
1205          * fill DTLB TR register
1206          */
1207         l.and   r4,r3,r4                // apply the mask
1208         // Determine number of DMMU sets
1209         l.mfspr r2, r0, SPR_DMMUCFGR
1210         l.andi  r2, r2, SPR_DMMUCFGR_NTS
1211         l.srli  r2, r2, SPR_DMMUCFGR_NTS_OFF
1212         l.ori   r3, r0, 0x1
1213         l.sll   r3, r3, r2      // r3 = number DMMU sets DMMUCFGR
1214         l.addi  r2, r3, -1      // r2 = nsets mask
1215         l.mfspr r3, r0, SPR_EEAR_BASE
1216         l.srli  r3, r3, 0xd     // >> PAGE_SHIFT
1217         l.and   r2, r3, r2      // calc offset:  & (NUM_TLB_ENTRIES-1)
1218                                                            //NUM_TLB_ENTRIES
1219         l.mtspr r2,r4,SPR_DTLBTR_BASE(0)
1220         /*
1221          * fill DTLB MR register
1222          */
1223         l.slli  r3, r3, 0xd             /* << PAGE_SHIFT => EA & PAGE_MASK */
1224         l.ori   r4,r3,0x1               // set hardware valid bit: DTBL_MR entry
1225         l.mtspr r2,r4,SPR_DTLBMR_BASE(0)
1226
1227         EXCEPTION_LOAD_GPR2
1228         EXCEPTION_LOAD_GPR3
1229         EXCEPTION_LOAD_GPR4
1230         l.rfe
1231 d_pmd_none:
1232 d_pte_not_present:
1233         EXCEPTION_LOAD_GPR2
1234         EXCEPTION_LOAD_GPR3
1235         EXCEPTION_LOAD_GPR4
1236         EXCEPTION_HANDLE(_dtlb_miss_page_fault_handler)
1237
1238 /* ==============================================[ ITLB miss handler ]=== */
1239 ENTRY(itlb_miss_handler)
1240         EXCEPTION_STORE_GPR2
1241         EXCEPTION_STORE_GPR3
1242         EXCEPTION_STORE_GPR4
1243         /*
1244          * get EA of the miss
1245          */
1246         l.mfspr r2,r0,SPR_EEAR_BASE
1247
1248         /*
1249          * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
1250          *
1251          */
1252         GET_CURRENT_PGD(r3,r4)          // r3 is current_pgd, r5 is temp
1253         l.srli  r4,r2,0x18              // >> PAGE_SHIFT + (PAGE_SHIFT - 2)
1254         l.slli  r4,r4,0x2               // to get address << 2
1255         l.add   r3,r4,r3                // r4 is pgd_index(daddr)
1256         /*
1257          * if (pmd_none(*pmd))
1258          *   goto pmd_none:
1259          */
1260         tophys  (r4,r3)
1261         l.lwz   r3,0x0(r4)              // get *pmd value
1262         l.sfne  r3,r0
1263         l.bnf   i_pmd_none
1264          l.addi r3,r0,0xffffe000        // PAGE_MASK
1265
1266 i_pmd_good:
1267         /*
1268          * pte = *pte_offset(pmd, iaddr);
1269          *
1270          */
1271         l.lwz   r4,0x0(r4)              // get **pmd value
1272         l.and   r4,r4,r3                // & PAGE_MASK
1273         l.srli  r2,r2,0xd               // >> PAGE_SHIFT, r2 == EEAR
1274         l.andi  r3,r2,0x7ff             // (1UL << PAGE_SHIFT - 2) - 1
1275         l.slli  r3,r3,0x2               // to get address << 2
1276         l.add   r3,r3,r4
1277         l.lwz   r3,0x0(r3)              // this is pte at last
1278         /*
1279          * if (!pte_present(pte))
1280          *
1281          */
1282         l.andi  r4,r3,0x1
1283         l.sfne  r4,r0                   // is pte present
1284         l.bnf   i_pte_not_present
1285          l.addi r4,r0,0xffffe03a        // PAGE_MASK | ITLB_UP_CONVERT_MASK
1286         /*
1287          * fill ITLB TR register
1288          */
1289         l.and   r4,r3,r4                // apply the mask
1290         l.andi  r3,r3,0x7c0             // _PAGE_EXEC | _PAGE_SRE | _PAGE_SWE |  _PAGE_URE | _PAGE_UWE
1291         l.sfeq  r3,r0
1292         l.bf    itlb_tr_fill //_workaround
1293         // Determine number of IMMU sets
1294         l.mfspr r2, r0, SPR_IMMUCFGR
1295         l.andi  r2, r2, SPR_IMMUCFGR_NTS
1296         l.srli  r2, r2, SPR_IMMUCFGR_NTS_OFF
1297         l.ori   r3, r0, 0x1
1298         l.sll   r3, r3, r2      // r3 = number IMMU sets IMMUCFGR
1299         l.addi  r2, r3, -1      // r2 = nsets mask
1300         l.mfspr r3, r0, SPR_EEAR_BASE
1301         l.srli  r3, r3, 0xd     // >> PAGE_SHIFT
1302         l.and   r2, r3, r2      // calc offset:  & (NUM_TLB_ENTRIES-1)
1303
1304 /*
1305  * __PHX__ :: fixme
1306  * we should not just blindly set executable flags,
1307  * but it does help with ping. the clean way would be to find out
1308  * (and fix it) why stack doesn't have execution permissions
1309  */
1310
1311 itlb_tr_fill_workaround:
1312         l.ori   r4,r4,0xc0              // | (SPR_ITLBTR_UXE | ITLBTR_SXE)
1313 itlb_tr_fill:
1314         l.mtspr r2,r4,SPR_ITLBTR_BASE(0)
1315         /*
1316          * fill DTLB MR register
1317          */
1318         l.slli  r3, r3, 0xd             /* << PAGE_SHIFT => EA & PAGE_MASK */
1319         l.ori   r4,r3,0x1               // set hardware valid bit: ITBL_MR entry
1320         l.mtspr r2,r4,SPR_ITLBMR_BASE(0)
1321
1322         EXCEPTION_LOAD_GPR2
1323         EXCEPTION_LOAD_GPR3
1324         EXCEPTION_LOAD_GPR4
1325         l.rfe
1326
1327 i_pmd_none:
1328 i_pte_not_present:
1329         EXCEPTION_LOAD_GPR2
1330         EXCEPTION_LOAD_GPR3
1331         EXCEPTION_LOAD_GPR4
1332         EXCEPTION_HANDLE(_itlb_miss_page_fault_handler)
1333
1334 /* ==============================================[ boot tlb handlers ]=== */
1335
1336
1337 /* =================================================[ debugging aids ]=== */
1338
1339 /*
1340  * DESC: Prints ASCII character stored in r7
1341  *
1342  * PRMS: r7     - a 32-bit value with an ASCII character in the first byte
1343  *              position.
1344  *
1345  * PREQ: The UART at UART_BASE_ADD has to be initialized
1346  *
1347  * POST: internally used but restores:
1348  *       r4     - to store UART_BASE_ADD
1349  *       r5     - for loading OFF_TXFULL / THRE,TEMT
1350  *       r6     - for storing bitmask (SERIAL_8250)
1351  */
1352 ENTRY(_emergency_putc)
1353         EMERGENCY_PRINT_STORE_GPR4
1354         EMERGENCY_PRINT_STORE_GPR5
1355         EMERGENCY_PRINT_STORE_GPR6
1356
1357         l.movhi r4,hi(UART_BASE_ADD)
1358         l.ori   r4,r4,lo(UART_BASE_ADD)
1359
1360 #if defined(CONFIG_SERIAL_LITEUART)
1361         /* Check OFF_TXFULL status */
1362 1:      l.lwz   r5,4(r4)
1363         l.andi  r5,r5,0xff
1364         l.sfnei r5,0
1365         l.bf    1b
1366          l.nop
1367
1368         /* Write character */
1369         l.andi  r7,r7,0xff
1370         l.sw    0(r4),r7
1371 #elif defined(CONFIG_SERIAL_8250)
1372         /* Check UART LSR THRE (hold) bit */
1373         l.addi  r6,r0,0x20
1374 1:      l.lbz   r5,5(r4)
1375         l.andi  r5,r5,0x20
1376         l.sfeq  r5,r6
1377         l.bnf   1b
1378          l.nop
1379
1380         /* Write character */
1381         l.sb    0(r4),r7
1382
1383         /* Check UART LSR THRE|TEMT (hold, empty) bits */
1384         l.addi  r6,r0,0x60
1385 1:      l.lbz   r5,5(r4)
1386         l.andi  r5,r5,0x60
1387         l.sfeq  r5,r6
1388         l.bnf   1b
1389          l.nop
1390 #endif
1391         EMERGENCY_PRINT_LOAD_GPR6
1392         EMERGENCY_PRINT_LOAD_GPR5
1393         EMERGENCY_PRINT_LOAD_GPR4
1394         l.jr    r9
1395          l.nop
1396
1397 /*
1398  * DSCR: prints a string referenced by r3.
1399  *
1400  * PRMS: r3             - address of the first character of null
1401  *                      terminated string to be printed
1402  *
1403  * PREQ: UART at UART_BASE_ADD has to be initialized
1404  *
1405  * POST: caller should be aware that r3, r9 are changed
1406  */
1407 ENTRY(_emergency_print)
1408         EMERGENCY_PRINT_STORE_GPR7
1409         EMERGENCY_PRINT_STORE_GPR9
1410
1411         /* Load character to r7, check for null terminator */
1412 2:      l.lbz   r7,0(r3)
1413         l.sfeqi r7,0x0
1414         l.bf    9f
1415          l.nop
1416
1417         l.jal   _emergency_putc
1418          l.nop
1419
1420         /* next character */
1421         l.j     2b
1422          l.addi r3,r3,0x1
1423
1424 9:
1425         EMERGENCY_PRINT_LOAD_GPR9
1426         EMERGENCY_PRINT_LOAD_GPR7
1427         l.jr    r9
1428          l.nop
1429
1430 /*
1431  * DSCR: prints a number in r3 in hex.
1432  *
1433  * PRMS: r3             - a 32-bit unsigned integer
1434  *
1435  * PREQ: UART at UART_BASE_ADD has to be initialized
1436  *
1437  * POST: caller should be aware that r3, r9 are changed
1438  */
1439 ENTRY(_emergency_print_nr)
1440         EMERGENCY_PRINT_STORE_GPR7
1441         EMERGENCY_PRINT_STORE_GPR8
1442         EMERGENCY_PRINT_STORE_GPR9
1443
1444         l.addi  r8,r0,32                // shift register
1445
1446 1:      /* remove leading zeros */
1447         l.addi  r8,r8,-0x4
1448         l.srl   r7,r3,r8
1449         l.andi  r7,r7,0xf
1450
1451         /* don't skip the last zero if number == 0x0 */
1452         l.sfeqi r8,0x4
1453         l.bf    2f
1454          l.nop
1455
1456         l.sfeq  r7,r0
1457         l.bf    1b
1458          l.nop
1459
1460 2:
1461         l.srl   r7,r3,r8
1462
1463         l.andi  r7,r7,0xf
1464         l.sflts r8,r0
1465          l.bf   9f
1466
1467         /* Numbers greater than 9 translate to a-f */
1468         l.sfgtui r7,0x9
1469         l.bnf   8f
1470          l.nop
1471         l.addi  r7,r7,0x27
1472
1473         /* Convert to ascii and output character */
1474 8:      l.jal   _emergency_putc
1475          l.addi r7,r7,0x30
1476
1477         /* next character */
1478         l.j     2b
1479         l.addi  r8,r8,-0x4
1480
1481 9:
1482         EMERGENCY_PRINT_LOAD_GPR9
1483         EMERGENCY_PRINT_LOAD_GPR8
1484         EMERGENCY_PRINT_LOAD_GPR7
1485         l.jr    r9
1486          l.nop
1487
1488 /*
1489  * This should be used for debugging only.
1490  * It messes up the Linux early serial output
1491  * somehow, so use it sparingly and essentially
1492  * only if you need to debug something that goes wrong
1493  * before Linux gets the early serial going.
1494  *
1495  * Furthermore, you'll have to make sure you set the
1496  * UART_DEVISOR correctly according to the system
1497  * clock rate.
1498  *
1499  *
1500  */
1501
1502
1503
1504 #define SYS_CLK            20000000
1505 //#define SYS_CLK            1843200
1506 #define OR32_CONSOLE_BAUD  115200
1507 #define UART_DIVISOR       SYS_CLK/(16*OR32_CONSOLE_BAUD)
1508
1509 ENTRY(_early_uart_init)
1510         l.movhi r3,hi(UART_BASE_ADD)
1511         l.ori   r3,r3,lo(UART_BASE_ADD)
1512
1513 #if defined(CONFIG_SERIAL_8250)
1514         l.addi  r4,r0,0x7
1515         l.sb    0x2(r3),r4
1516
1517         l.addi  r4,r0,0x0
1518         l.sb    0x1(r3),r4
1519
1520         l.addi  r4,r0,0x3
1521         l.sb    0x3(r3),r4
1522
1523         l.lbz   r5,3(r3)
1524         l.ori   r4,r5,0x80
1525         l.sb    0x3(r3),r4
1526         l.addi  r4,r0,((UART_DIVISOR>>8) & 0x000000ff)
1527         l.sb    UART_DLM(r3),r4
1528         l.addi  r4,r0,((UART_DIVISOR) & 0x000000ff)
1529         l.sb    UART_DLL(r3),r4
1530         l.sb    0x3(r3),r5
1531 #endif
1532
1533         l.jr    r9
1534          l.nop
1535
1536         .align  0x1000
1537         .global _secondary_evbar
1538 _secondary_evbar:
1539
1540         .space 0x800
1541         /* Just disable interrupts and Return */
1542         l.ori   r3,r0,SPR_SR_SM
1543         l.mtspr r0,r3,SPR_ESR_BASE
1544         l.rfe
1545
1546
1547         .section .rodata
1548 _string_unhandled_exception:
1549         .string "\r\nRunarunaround: Unhandled exception 0x\0"
1550
1551 _string_epc_prefix:
1552         .string ": EPC=0x\0"
1553
1554 _string_nl:
1555         .string "\r\n\0"
1556
1557
1558 /* ========================================[ page aligned structures ]=== */
1559
1560 /*
1561  * .data section should be page aligned
1562  *      (look into arch/openrisc/kernel/vmlinux.lds.S)
1563  */
1564         .section .data,"aw"
1565         .align  8192
1566         .global  empty_zero_page
1567 empty_zero_page:
1568         .space  8192
1569
1570         .global  swapper_pg_dir
1571 swapper_pg_dir:
1572         .space  8192
1573
1574         .global _unhandled_stack
1575 _unhandled_stack:
1576         .space  8192
1577 _unhandled_stack_top:
1578
1579 /* ============================================================[ EOF ]=== */