arch/mips/kernel/genex.S

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1994 - 2000, 2001, 2003 Ralf Baechle
   7  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   8  * Copyright (C) 2002, 2007  Maciej W. Rozycki
   9  * Copyright (C) 2001, 2012 MIPS Technologies, Inc.  All rights reserved.
  10  */
  11 #include <linux/init.h>
  12
  13 #include <asm/asm.h>
  14 #include <asm/asmmacro.h>
  15 #include <asm/cacheops.h>
  16 #include <asm/irqflags.h>
  17 #include <asm/regdef.h>
  18 #include <asm/fpregdef.h>
  19 #include <asm/mipsregs.h>
  20 #include <asm/stackframe.h>
  21 #include <asm/war.h>
  22 #include <asm/thread_info.h>
  23
  24         __INIT
  25
  26 /*
  27  * General exception vector for all other CPUs.
  28  *
  29  * Be careful when changing this, it has to be at most 128 bytes
  30  * to fit into space reserved for the exception handler.
  31  */
  32 NESTED(except_vec3_generic, 0, sp)
  33         .set    push
  34         .set    noat
  35 #if R5432_CP0_INTERRUPT_WAR
  36         mfc0    k0, CP0_INDEX
  37 #endif
  38         mfc0    k1, CP0_CAUSE
  39         andi    k1, k1, 0x7c
  40 #ifdef CONFIG_64BIT
  41         dsll    k1, k1, 1
  42 #endif
  43         PTR_L   k0, exception_handlers(k1)
  44         jr      k0
  45         .set    pop
  46         END(except_vec3_generic)
  47
  48 /*
  49  * General exception handler for CPUs with virtual coherency exception.
  50  *
  51  * Be careful when changing this, it has to be at most 256 (as a special
  52  * exception) bytes to fit into space reserved for the exception handler.
  53  */
  54 NESTED(except_vec3_r4000, 0, sp)
  55         .set    push
  56         .set    arch=r4000
  57         .set    noat
  58         mfc0    k1, CP0_CAUSE
  59         li      k0, 31<<2
  60         andi    k1, k1, 0x7c
  61         .set    push
  62         .set    noreorder
  63         .set    nomacro
  64         beq     k1, k0, handle_vced
  65          li     k0, 14<<2
  66         beq     k1, k0, handle_vcei
  67 #ifdef CONFIG_64BIT
  68          dsll   k1, k1, 1
  69 #endif
  70         .set    pop
  71         PTR_L   k0, exception_handlers(k1)
  72         jr      k0
  73
  74         /*
  75          * Big shit, we now may have two dirty primary cache lines for the same
  76          * physical address.  We can safely invalidate the line pointed to by
  77          * c0_badvaddr because after return from this exception handler the
  78          * load / store will be re-executed.
  79          */
  80 handle_vced:
  81         MFC0    k0, CP0_BADVADDR
  82         li      k1, -4                                  # Is this ...
  83         and     k0, k1                                  # ... really needed?
  84         mtc0    zero, CP0_TAGLO
  85         cache   Index_Store_Tag_D, (k0)
  86         cache   Hit_Writeback_Inv_SD, (k0)
  87 #ifdef CONFIG_PROC_FS
  88         PTR_LA  k0, vced_count
  89         lw      k1, (k0)
  90         addiu   k1, 1
  91         sw      k1, (k0)
  92 #endif
  93         eret
  94
  95 handle_vcei:
  96         MFC0    k0, CP0_BADVADDR
  97         cache   Hit_Writeback_Inv_SD, (k0)              # also cleans pi
  98 #ifdef CONFIG_PROC_FS
  99         PTR_LA  k0, vcei_count
 100         lw      k1, (k0)
 101         addiu   k1, 1
 102         sw      k1, (k0)
 103 #endif
 104         eret
 105         .set    pop
 106         END(except_vec3_r4000)
 107
 108         __FINIT
 109
 110         .align  5       /* 32 byte rollback region */
 111 LEAF(__r4k_wait)
 112         .set    push
 113         .set    noreorder
 114         /* start of rollback region */
 115         LONG_L  t0, TI_FLAGS($28)
 116         nop
 117         andi    t0, _TIF_NEED_RESCHED
 118         bnez    t0, 1f
 119          nop
 120         nop
 121         nop
 122 #ifdef CONFIG_CPU_MICROMIPS
 123         nop
 124         nop
 125         nop
 126         nop
 127 #endif
 128         .set    arch=r4000
 129         wait
 130         /* end of rollback region (the region size must be power of two) */
 131 1:
 132         jr      ra
 133         nop
 134         .set    pop
 135         END(__r4k_wait)
 136
 137         .macro  BUILD_ROLLBACK_PROLOGUE handler
 138         FEXPORT(rollback_\handler)
 139         .set    push
 140         .set    noat
 141         MFC0    k0, CP0_EPC
 142         PTR_LA  k1, __r4k_wait
 143         ori     k0, 0x1f        /* 32 byte rollback region */
 144         xori    k0, 0x1f
 145         bne     k0, k1, 9f
 146         MTC0    k0, CP0_EPC
 147 9:
 148         .set pop
 149         .endm
 150
 151         .align  5
 152 BUILD_ROLLBACK_PROLOGUE handle_int
 153 NESTED(handle_int, PT_SIZE, sp)
 154 #ifdef CONFIG_TRACE_IRQFLAGS
 155         /*
 156          * Check to see if the interrupted code has just disabled
 157          * interrupts and ignore this interrupt for now if so.
 158          *
 159          * local_irq_disable() disables interrupts and then calls
 160          * trace_hardirqs_off() to track the state. If an interrupt is taken
 161          * after interrupts are disabled but before the state is updated
 162          * it will appear to restore_all that it is incorrectly returning with
 163          * interrupts disabled
 164          */
 165         .set    push
 166         .set    noat
 167         mfc0    k0, CP0_STATUS
 168 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
 169         and     k0, ST0_IEP
 170         bnez    k0, 1f
 171
 172         mfc0    k0, CP0_EPC
 173         .set    noreorder
 174         j       k0
 175         rfe
 176 #else
 177         and     k0, ST0_IE
 178         bnez    k0, 1f
 179
 180         eret
 181 #endif
 182 1:
 183         .set pop
 184 #endif
 185         SAVE_ALL
 186         CLI
 187         TRACE_IRQS_OFF
 188
 189         LONG_L  s0, TI_REGS($28)
 190         LONG_S  sp, TI_REGS($28)
 191         PTR_LA  ra, ret_from_irq
 192         PTR_LA  v0, plat_irq_dispatch
 193         jr      v0
 194 #ifdef CONFIG_CPU_MICROMIPS
 195         nop
 196 #endif
 197         END(handle_int)
 198
 199         __INIT
 200
 201 /*
 202  * Special interrupt vector for MIPS64 ISA & embedded MIPS processors.
 203  * This is a dedicated interrupt exception vector which reduces the
 204  * interrupt processing overhead.  The jump instruction will be replaced
 205  * at the initialization time.
 206  *
 207  * Be careful when changing this, it has to be at most 128 bytes
 208  * to fit into space reserved for the exception handler.
 209  */
 210 NESTED(except_vec4, 0, sp)
 211 1:      j       1b                      /* Dummy, will be replaced */
 212         END(except_vec4)
 213
 214 /*
 215  * EJTAG debug exception handler.
 216  * The EJTAG debug exception entry point is 0xbfc00480, which
 217  * normally is in the boot PROM, so the boot PROM must do an
 218  * unconditional jump to this vector.
 219  */
 220 NESTED(except_vec_ejtag_debug, 0, sp)
 221         j       ejtag_debug_handler
 222 #ifdef CONFIG_CPU_MICROMIPS
 223          nop
 224 #endif
 225         END(except_vec_ejtag_debug)
 226
 227         __FINIT
 228
 229 /*
 230  * Vectored interrupt handler.
 231  * This prototype is copied to ebase + n*IntCtl.VS and patched
 232  * to invoke the handler
 233  */
 234 BUILD_ROLLBACK_PROLOGUE except_vec_vi
 235 NESTED(except_vec_vi, 0, sp)
 236         SAVE_SOME
 237         SAVE_AT
 238         .set    push
 239         .set    noreorder
 240         PTR_LA  v1, except_vec_vi_handler
 241 FEXPORT(except_vec_vi_lui)
 242         lui     v0, 0           /* Patched */
 243         jr      v1
 244 FEXPORT(except_vec_vi_ori)
 245          ori    v0, 0           /* Patched */
 246         .set    pop
 247         END(except_vec_vi)
 248 EXPORT(except_vec_vi_end)
 249
 250 /*
 251  * Common Vectored Interrupt code
 252  * Complete the register saves and invoke the handler which is passed in $v0
 253  */
 254 NESTED(except_vec_vi_handler, 0, sp)
 255         SAVE_TEMP
 256         SAVE_STATIC
 257         CLI
 258 #ifdef CONFIG_TRACE_IRQFLAGS
 259         move    s0, v0
 260         TRACE_IRQS_OFF
 261         move    v0, s0
 262 #endif
 263
 264         LONG_L  s0, TI_REGS($28)
 265         LONG_S  sp, TI_REGS($28)
 266         PTR_LA  ra, ret_from_irq
 267         jr      v0
 268         END(except_vec_vi_handler)
 269
 270 /*
 271  * EJTAG debug exception handler.
 272  */
 273 NESTED(ejtag_debug_handler, PT_SIZE, sp)
 274         .set    push
 275         .set    noat
 276         MTC0    k0, CP0_DESAVE
 277         mfc0    k0, CP0_DEBUG
 278
 279         sll     k0, k0, 30      # Check for SDBBP.
 280         bgez    k0, ejtag_return
 281
 282         PTR_LA  k0, ejtag_debug_buffer
 283         LONG_S  k1, 0(k0)
 284         SAVE_ALL
 285         move    a0, sp
 286         jal     ejtag_exception_handler
 287         RESTORE_ALL
 288         PTR_LA  k0, ejtag_debug_buffer
 289         LONG_L  k1, 0(k0)
 290
 291 ejtag_return:
 292         MFC0    k0, CP0_DESAVE
 293         .set    mips32
 294         deret
 295         .set pop
 296         END(ejtag_debug_handler)
 297
 298 /*
 299  * This buffer is reserved for the use of the EJTAG debug
 300  * handler.
 301  */
 302         .data
 303 EXPORT(ejtag_debug_buffer)
 304         .fill   LONGSIZE
 305         .previous
 306
 307         __INIT
 308
 309 /*
 310  * NMI debug exception handler for MIPS reference boards.
 311  * The NMI debug exception entry point is 0xbfc00000, which
 312  * normally is in the boot PROM, so the boot PROM must do a
 313  * unconditional jump to this vector.
 314  */
 315 NESTED(except_vec_nmi, 0, sp)
 316         j       nmi_handler
 317 #ifdef CONFIG_CPU_MICROMIPS
 318          nop
 319 #endif
 320         END(except_vec_nmi)
 321
 322         __FINIT
 323
 324 NESTED(nmi_handler, PT_SIZE, sp)
 325         .set    push
 326         .set    noat
 327         /*
 328          * Clear ERL - restore segment mapping
 329          * Clear BEV - required for page fault exception handler to work
 330          */
 331         mfc0    k0, CP0_STATUS
 332         ori     k0, k0, ST0_EXL
 333         li      k1, ~(ST0_BEV | ST0_ERL)
 334         and     k0, k0, k1
 335         mtc0    k0, CP0_STATUS
 336         _ehb
 337         SAVE_ALL
 338         move    a0, sp
 339         jal     nmi_exception_handler
 340         /* nmi_exception_handler never returns */
 341         .set    pop
 342         END(nmi_handler)
 343
 344         .macro  __build_clear_none
 345         .endm
 346
 347         .macro  __build_clear_sti
 348         TRACE_IRQS_ON
 349         STI
 350         .endm
 351
 352         .macro  __build_clear_cli
 353         CLI
 354         TRACE_IRQS_OFF
 355         .endm
 356
 357         .macro  __build_clear_fpe
 358         .set    push
 359         /* gas fails to assemble cfc1 for some archs (octeon).*/ \
 360         .set    mips1
 361         SET_HARDFLOAT
 362         cfc1    a1, fcr31
 363         li      a2, ~(0x3f << 12)
 364         and     a2, a1
 365         ctc1    a2, fcr31
 366         .set    pop
 367         TRACE_IRQS_ON
 368         STI
 369         .endm
 370
 371         .macro  __build_clear_ade
 372         MFC0    t0, CP0_BADVADDR
 373         PTR_S   t0, PT_BVADDR(sp)
 374         KMODE
 375         .endm
 376
 377         .macro  __BUILD_silent exception
 378         .endm
 379
 380         /* Gas tries to parse the PRINT argument as a string containing
 381            string escapes and emits bogus warnings if it believes to
 382            recognize an unknown escape code.  So make the arguments
 383            start with an n and gas will believe \n is ok ...  */
 384         .macro  __BUILD_verbose nexception
 385         LONG_L  a1, PT_EPC(sp)
 386 #ifdef CONFIG_32BIT
 387         PRINT("Got \nexception at %08lx\012")
 388 #endif
 389 #ifdef CONFIG_64BIT
 390         PRINT("Got \nexception at %016lx\012")
 391 #endif
 392         .endm
 393
 394         .macro  __BUILD_count exception
 395         LONG_L  t0,exception_count_\exception
 396         LONG_ADDIU t0, 1
 397         LONG_S  t0,exception_count_\exception
 398         .comm   exception_count\exception, 8, 8
 399         .endm
 400
 401         .macro  __BUILD_HANDLER exception handler clear verbose ext
 402         .align  5
 403         NESTED(handle_\exception, PT_SIZE, sp)
 404         .set    noat
 405         SAVE_ALL
 406         FEXPORT(handle_\exception\ext)
 407         __BUILD_clear_\clear
 408         .set    at
 409         __BUILD_\verbose \exception
 410         move    a0, sp
 411         PTR_LA  ra, ret_from_exception
 412         j       do_\handler
 413         END(handle_\exception)
 414         .endm
 415
 416         .macro  BUILD_HANDLER exception handler clear verbose
 417         __BUILD_HANDLER \exception \handler \clear \verbose _int
 418         .endm
 419
 420         BUILD_HANDLER adel ade ade silent               /* #4  */
 421         BUILD_HANDLER ades ade ade silent               /* #5  */
 422         BUILD_HANDLER ibe be cli silent                 /* #6  */
 423         BUILD_HANDLER dbe be cli silent                 /* #7  */
 424         BUILD_HANDLER bp bp sti silent                  /* #9  */
 425         BUILD_HANDLER ri ri sti silent                  /* #10 */
 426         BUILD_HANDLER cpu cpu sti silent                /* #11 */
 427         BUILD_HANDLER ov ov sti silent                  /* #12 */
 428         BUILD_HANDLER tr tr sti silent                  /* #13 */
 429         BUILD_HANDLER msa_fpe msa_fpe sti silent        /* #14 */
 430         BUILD_HANDLER fpe fpe fpe silent                /* #15 */
 431         BUILD_HANDLER ftlb ftlb none silent             /* #16 */
 432         BUILD_HANDLER msa msa sti silent                /* #21 */
 433         BUILD_HANDLER mdmx mdmx sti silent              /* #22 */
 434 #ifdef  CONFIG_HARDWARE_WATCHPOINTS
 435         /*
 436          * For watch, interrupts will be enabled after the watch
 437          * registers are read.
 438          */
 439         BUILD_HANDLER watch watch cli silent            /* #23 */
 440 #else
 441         BUILD_HANDLER watch watch sti verbose           /* #23 */
 442 #endif
 443         BUILD_HANDLER mcheck mcheck cli verbose         /* #24 */
 444         BUILD_HANDLER mt mt sti silent                  /* #25 */
 445         BUILD_HANDLER dsp dsp sti silent                /* #26 */
 446         BUILD_HANDLER reserved reserved sti verbose     /* others */
 447
 448         .align  5
 449         LEAF(handle_ri_rdhwr_vivt)
 450         .set    push
 451         .set    noat
 452         .set    noreorder
 453         /* check if TLB contains a entry for EPC */
 454         MFC0    k1, CP0_ENTRYHI
 455         andi    k1, 0xff        /* ASID_MASK */
 456         MFC0    k0, CP0_EPC
 457         PTR_SRL k0, _PAGE_SHIFT + 1
 458         PTR_SLL k0, _PAGE_SHIFT + 1
 459         or      k1, k0
 460         MTC0    k1, CP0_ENTRYHI
 461         mtc0_tlbw_hazard
 462         tlbp
 463         tlb_probe_hazard
 464         mfc0    k1, CP0_INDEX
 465         .set    pop
 466         bltz    k1, handle_ri   /* slow path */
 467         /* fall thru */
 468         END(handle_ri_rdhwr_vivt)
 469
 470         LEAF(handle_ri_rdhwr)
 471         .set    push
 472         .set    noat
 473         .set    noreorder
 474         /* MIPS32:    0x7c03e83b: rdhwr v1,$29 */
 475         /* microMIPS: 0x007d6b3c: rdhwr v1,$29 */
 476         MFC0    k1, CP0_EPC
 477 #if defined(CONFIG_CPU_MICROMIPS) || defined(CONFIG_CPU_MIPS32_R2) || defined(CONFIG_CPU_MIPS64_R2)
 478         and     k0, k1, 1
 479         beqz    k0, 1f
 480         xor     k1, k0
 481         lhu     k0, (k1)
 482         lhu     k1, 2(k1)
 483         ins     k1, k0, 16, 16
 484         lui     k0, 0x007d
 485         b       docheck
 486         ori     k0, 0x6b3c
 487 1:
 488         lui     k0, 0x7c03
 489         lw      k1, (k1)
 490         ori     k0, 0xe83b
 491 #else
 492         andi    k0, k1, 1
 493         bnez    k0, handle_ri
 494         lui     k0, 0x7c03
 495         lw      k1, (k1)
 496         ori     k0, 0xe83b
 497 #endif
 498         .set    reorder
 499 docheck:
 500         bne     k0, k1, handle_ri       /* if not ours */
 501
 502 isrdhwr:
 503         /* The insn is rdhwr.  No need to check CAUSE.BD here. */
 504         get_saved_sp    /* k1 := current_thread_info */
 505         .set    noreorder
 506         MFC0    k0, CP0_EPC
 507 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
 508         ori     k1, _THREAD_MASK
 509         xori    k1, _THREAD_MASK
 510         LONG_L  v1, TI_TP_VALUE(k1)
 511         LONG_ADDIU      k0, 4
 512         jr      k0
 513          rfe
 514 #else
 515 #ifndef CONFIG_CPU_DADDI_WORKAROUNDS
 516         LONG_ADDIU      k0, 4           /* stall on $k0 */
 517 #else
 518         .set    at=v1
 519         LONG_ADDIU      k0, 4
 520         .set    noat
 521 #endif
 522         MTC0    k0, CP0_EPC
 523         /* I hope three instructions between MTC0 and ERET are enough... */
 524         ori     k1, _THREAD_MASK
 525         xori    k1, _THREAD_MASK
 526         LONG_L  v1, TI_TP_VALUE(k1)
 527         .set    arch=r4000
 528         eret
 529         .set    mips0
 530 #endif
 531         .set    pop
 532         END(handle_ri_rdhwr)
 533
 534 #ifdef CONFIG_64BIT
 535 /* A temporary overflow handler used by check_daddi(). */
 536
 537         __INIT
 538
 539         BUILD_HANDLER  daddi_ov daddi_ov none silent    /* #12 */
 540 #endif