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/sync.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 mfc0 k1, CP0_CAUSE
36 andi k1, k1, 0x7c
37 #ifdef CONFIG_64BIT
38 dsll k1, k1, 1
39 #endif
40 PTR_L k0, exception_handlers(k1)
41 jr k0
42 .set pop
43 END(except_vec3_generic)
44
45 /*
46 * General exception handler for CPUs with virtual coherency exception.
47 *
48 * Be careful when changing this, it has to be at most 256 (as a special
49 * exception) bytes to fit into space reserved for the exception handler.
50 */
51 NESTED(except_vec3_r4000, 0, sp)
52 .set push
53 .set arch=r4000
54 .set noat
55 mfc0 k1, CP0_CAUSE
56 li k0, 31<<2
57 andi k1, k1, 0x7c
58 .set push
59 .set noreorder
60 .set nomacro
61 beq k1, k0, handle_vced
62 li k0, 14<<2
63 beq k1, k0, handle_vcei
64 #ifdef CONFIG_64BIT
65 dsll k1, k1, 1
66 #endif
67 .set pop
68 PTR_L k0, exception_handlers(k1)
69 jr k0
70
71 /*
72 * Big shit, we now may have two dirty primary cache lines for the same
73 * physical address. We can safely invalidate the line pointed to by
74 * c0_badvaddr because after return from this exception handler the
75 * load / store will be re-executed.
76 */
77 handle_vced:
78 MFC0 k0, CP0_BADVADDR
79 li k1, -4 # Is this ...
80 and k0, k1 # ... really needed?
81 mtc0 zero, CP0_TAGLO
82 cache Index_Store_Tag_D, (k0)
83 cache Hit_Writeback_Inv_SD, (k0)
84 #ifdef CONFIG_PROC_FS
85 PTR_LA k0, vced_count
86 lw k1, (k0)
87 addiu k1, 1
88 sw k1, (k0)
89 #endif
90 eret
91
92 handle_vcei:
93 MFC0 k0, CP0_BADVADDR
94 cache Hit_Writeback_Inv_SD, (k0) # also cleans pi
95 #ifdef CONFIG_PROC_FS
96 PTR_LA k0, vcei_count
97 lw k1, (k0)
98 addiu k1, 1
99 sw k1, (k0)
100 #endif
101 eret
102 .set pop
103 END(except_vec3_r4000)
104
105 __FINIT
106
107 .align 5 /* 32 byte rollback region */
108 LEAF(__r4k_wait)
109 .set push
110 .set noreorder
111 /* start of rollback region */
112 LONG_L t0, TI_FLAGS($28)
113 nop
114 andi t0, _TIF_NEED_RESCHED
115 bnez t0, 1f
116 nop
117 nop
118 nop
119 #ifdef CONFIG_CPU_MICROMIPS
120 nop
121 nop
122 nop
123 nop
124 #endif
125 .set MIPS_ISA_ARCH_LEVEL_RAW
126 wait
127 /* end of rollback region (the region size must be power of two) */
128 1:
129 jr ra
130 nop
131 .set pop
132 END(__r4k_wait)
133
134 .macro BUILD_ROLLBACK_PROLOGUE handler
135 FEXPORT(rollback_\handler)
136 .set push
137 .set noat
138 MFC0 k0, CP0_EPC
139 PTR_LA k1, __r4k_wait
140 ori k0, 0x1f /* 32 byte rollback region */
141 xori k0, 0x1f
142 bne k0, k1, \handler
143 MTC0 k0, CP0_EPC
144 .set pop
145 .endm
146
147 .align 5
148 BUILD_ROLLBACK_PROLOGUE handle_int
149 NESTED(handle_int, PT_SIZE, sp)
150 .cfi_signal_frame
151 #ifdef CONFIG_TRACE_IRQFLAGS
152 /*
153 * Check to see if the interrupted code has just disabled
154 * interrupts and ignore this interrupt for now if so.
155 *
156 * local_irq_disable() disables interrupts and then calls
157 * trace_hardirqs_off() to track the state. If an interrupt is taken
158 * after interrupts are disabled but before the state is updated
159 * it will appear to restore_all that it is incorrectly returning with
160 * interrupts disabled
161 */
162 .set push
163 .set noat
164 mfc0 k0, CP0_STATUS
165 #if defined(CONFIG_CPU_R3000)
166 and k0, ST0_IEP
167 bnez k0, 1f
168
169 mfc0 k0, CP0_EPC
170 .set noreorder
171 j k0
172 rfe
173 #else
174 and k0, ST0_IE
175 bnez k0, 1f
176
177 eret
178 #endif
179 1:
180 .set pop
181 #endif
182 SAVE_ALL docfi=1
183 CLI
184 TRACE_IRQS_OFF
185
186 LONG_L s0, TI_REGS($28)
187 LONG_S sp, TI_REGS($28)
188
189 /*
190 * SAVE_ALL ensures we are using a valid kernel stack for the thread.
191 * Check if we are already using the IRQ stack.
192 */
193 move s1, sp # Preserve the sp
194
195 /* Get IRQ stack for this CPU */
196 ASM_CPUID_MFC0 k0, ASM_SMP_CPUID_REG
197 #if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
198 lui k1, %hi(irq_stack)
199 #else
200 lui k1, %highest(irq_stack)
201 daddiu k1, %higher(irq_stack)
202 dsll k1, 16
203 daddiu k1, %hi(irq_stack)
204 dsll k1, 16
205 #endif
206 LONG_SRL k0, SMP_CPUID_PTRSHIFT
207 LONG_ADDU k1, k0
208 LONG_L t0, %lo(irq_stack)(k1)
209
210 # Check if already on IRQ stack
211 PTR_LI t1, ~(_THREAD_SIZE-1)
212 and t1, t1, sp
213 beq t0, t1, 2f
214
215 /* Switch to IRQ stack */
216 li t1, _IRQ_STACK_START
217 PTR_ADD sp, t0, t1
218
219 /* Save task's sp on IRQ stack so that unwinding can follow it */
220 LONG_S s1, 0(sp)
221 2:
222 jal plat_irq_dispatch
223
224 /* Restore sp */
225 move sp, s1
226
227 j ret_from_irq
228 #ifdef CONFIG_CPU_MICROMIPS
229 nop
230 #endif
231 END(handle_int)
232
233 __INIT
234
235 /*
236 * Special interrupt vector for MIPS64 ISA & embedded MIPS processors.
237 * This is a dedicated interrupt exception vector which reduces the
238 * interrupt processing overhead. The jump instruction will be replaced
239 * at the initialization time.
240 *
241 * Be careful when changing this, it has to be at most 128 bytes
242 * to fit into space reserved for the exception handler.
243 */
244 NESTED(except_vec4, 0, sp)
245 1: j 1b /* Dummy, will be replaced */
246 END(except_vec4)
247
248 /*
249 * EJTAG debug exception handler.
250 * The EJTAG debug exception entry point is 0xbfc00480, which
251 * normally is in the boot PROM, so the boot PROM must do an
252 * unconditional jump to this vector.
253 */
254 NESTED(except_vec_ejtag_debug, 0, sp)
255 j ejtag_debug_handler
256 #ifdef CONFIG_CPU_MICROMIPS
257 nop
258 #endif
259 END(except_vec_ejtag_debug)
260
261 __FINIT
262
263 /*
264 * Vectored interrupt handler.
265 * This prototype is copied to ebase + n*IntCtl.VS and patched
266 * to invoke the handler
267 */
268 BUILD_ROLLBACK_PROLOGUE except_vec_vi
269 NESTED(except_vec_vi, 0, sp)
270 SAVE_SOME docfi=1
271 SAVE_AT docfi=1
272 .set push
273 .set noreorder
274 PTR_LA v1, except_vec_vi_handler
275 jr v1
276 FEXPORT(except_vec_vi_ori)
277 ori v0, zero, 0 /* Offset in vi_handlers[] */
278 .set pop
279 END(except_vec_vi)
280 EXPORT(except_vec_vi_end)
281
282 /*
283 * Common Vectored Interrupt code
284 * Complete the register saves and invoke the handler, $v0 holds
285 * offset into vi_handlers[]
286 */
287 NESTED(except_vec_vi_handler, 0, sp)
288 SAVE_TEMP
289 SAVE_STATIC
290 CLI
291 #ifdef CONFIG_TRACE_IRQFLAGS
292 move s0, v0
293 TRACE_IRQS_OFF
294 move v0, s0
295 #endif
296
297 LONG_L s0, TI_REGS($28)
298 LONG_S sp, TI_REGS($28)
299
300 /*
301 * SAVE_ALL ensures we are using a valid kernel stack for the thread.
302 * Check if we are already using the IRQ stack.
303 */
304 move s1, sp # Preserve the sp
305
306 /* Get IRQ stack for this CPU */
307 ASM_CPUID_MFC0 k0, ASM_SMP_CPUID_REG
308 #if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
309 lui k1, %hi(irq_stack)
310 #else
311 lui k1, %highest(irq_stack)
312 daddiu k1, %higher(irq_stack)
313 dsll k1, 16
314 daddiu k1, %hi(irq_stack)
315 dsll k1, 16
316 #endif
317 LONG_SRL k0, SMP_CPUID_PTRSHIFT
318 LONG_ADDU k1, k0
319 LONG_L t0, %lo(irq_stack)(k1)
320
321 # Check if already on IRQ stack
322 PTR_LI t1, ~(_THREAD_SIZE-1)
323 and t1, t1, sp
324 beq t0, t1, 2f
325
326 /* Switch to IRQ stack */
327 li t1, _IRQ_STACK_START
328 PTR_ADD sp, t0, t1
329
330 /* Save task's sp on IRQ stack so that unwinding can follow it */
331 LONG_S s1, 0(sp)
332 2:
333 PTR_L v0, vi_handlers(v0)
334 jalr v0
335
336 /* Restore sp */
337 move sp, s1
338
339 j ret_from_irq
340 END(except_vec_vi_handler)
341
342 /*
343 * EJTAG debug exception handler.
344 */
345 NESTED(ejtag_debug_handler, PT_SIZE, sp)
346 .set push
347 .set noat
348 MTC0 k0, CP0_DESAVE
349 mfc0 k0, CP0_DEBUG
350
351 andi k0, k0, MIPS_DEBUG_DBP # Check for SDBBP.
352 beqz k0, ejtag_return
353
354 #ifdef CONFIG_SMP
355 1: PTR_LA k0, ejtag_debug_buffer_spinlock
356 __SYNC(full, loongson3_war)
357 2: ll k0, 0(k0)
358 bnez k0, 2b
359 PTR_LA k0, ejtag_debug_buffer_spinlock
360 sc k0, 0(k0)
361 beqz k0, 1b
362 # ifdef CONFIG_WEAK_REORDERING_BEYOND_LLSC
363 sync
364 # endif
365
366 PTR_LA k0, ejtag_debug_buffer
367 LONG_S k1, 0(k0)
368
369 ASM_CPUID_MFC0 k1, ASM_SMP_CPUID_REG
370 PTR_SRL k1, SMP_CPUID_PTRSHIFT
371 PTR_SLL k1, LONGLOG
372 PTR_LA k0, ejtag_debug_buffer_per_cpu
373 PTR_ADDU k0, k1
374
375 PTR_LA k1, ejtag_debug_buffer
376 LONG_L k1, 0(k1)
377 LONG_S k1, 0(k0)
378
379 PTR_LA k0, ejtag_debug_buffer_spinlock
380 sw zero, 0(k0)
381 #else
382 PTR_LA k0, ejtag_debug_buffer
383 LONG_S k1, 0(k0)
384 #endif
385
386 SAVE_ALL
387 move a0, sp
388 jal ejtag_exception_handler
389 RESTORE_ALL
390
391 #ifdef CONFIG_SMP
392 ASM_CPUID_MFC0 k1, ASM_SMP_CPUID_REG
393 PTR_SRL k1, SMP_CPUID_PTRSHIFT
394 PTR_SLL k1, LONGLOG
395 PTR_LA k0, ejtag_debug_buffer_per_cpu
396 PTR_ADDU k0, k1
397 LONG_L k1, 0(k0)
398 #else
399 PTR_LA k0, ejtag_debug_buffer
400 LONG_L k1, 0(k0)
401 #endif
402
403 ejtag_return:
404 back_to_back_c0_hazard
405 MFC0 k0, CP0_DESAVE
406 .set mips32
407 deret
408 .set pop
409 END(ejtag_debug_handler)
410
411 /*
412 * This buffer is reserved for the use of the EJTAG debug
413 * handler.
414 */
415 .data
416 EXPORT(ejtag_debug_buffer)
417 .fill LONGSIZE
418 #ifdef CONFIG_SMP
419 EXPORT(ejtag_debug_buffer_spinlock)
420 .fill LONGSIZE
421 EXPORT(ejtag_debug_buffer_per_cpu)
422 .fill LONGSIZE * NR_CPUS
423 #endif
424 .previous
425
426 __INIT
427
428 /*
429 * NMI debug exception handler for MIPS reference boards.
430 * The NMI debug exception entry point is 0xbfc00000, which
431 * normally is in the boot PROM, so the boot PROM must do a
432 * unconditional jump to this vector.
433 */
434 NESTED(except_vec_nmi, 0, sp)
435 j nmi_handler
436 #ifdef CONFIG_CPU_MICROMIPS
437 nop
438 #endif
439 END(except_vec_nmi)
440
441 __FINIT
442
443 NESTED(nmi_handler, PT_SIZE, sp)
444 .cfi_signal_frame
445 .set push
446 .set noat
447 /*
448 * Clear ERL - restore segment mapping
449 * Clear BEV - required for page fault exception handler to work
450 */
451 mfc0 k0, CP0_STATUS
452 ori k0, k0, ST0_EXL
453 li k1, ~(ST0_BEV | ST0_ERL)
454 and k0, k0, k1
455 mtc0 k0, CP0_STATUS
456 _ehb
457 SAVE_ALL
458 move a0, sp
459 jal nmi_exception_handler
460 /* nmi_exception_handler never returns */
461 .set pop
462 END(nmi_handler)
463
464 .macro __build_clear_none
465 .endm
466
467 .macro __build_clear_sti
468 TRACE_IRQS_ON
469 STI
470 .endm
471
472 .macro __build_clear_cli
473 CLI
474 TRACE_IRQS_OFF
475 .endm
476
477 .macro __build_clear_fpe
478 CLI
479 TRACE_IRQS_OFF
480 .set push
481 /* gas fails to assemble cfc1 for some archs (octeon).*/ \
482 .set mips1
483 .set hardfloat
484 cfc1 a1, fcr31
485 .set pop
486 .endm
487
488 .macro __build_clear_msa_fpe
489 CLI
490 TRACE_IRQS_OFF
491 _cfcmsa a1, MSA_CSR
492 .endm
493
494 .macro __build_clear_ade
495 MFC0 t0, CP0_BADVADDR
496 PTR_S t0, PT_BVADDR(sp)
497 KMODE
498 .endm
499
500 .macro __build_clear_gsexc
501 .set push
502 /*
503 * We need to specify a selector to access the CP0.Diag1 (GSCause)
504 * register. All GSExc-equipped processors have MIPS32.
505 */
506 .set mips32
507 mfc0 a1, CP0_DIAGNOSTIC1
508 .set pop
509 TRACE_IRQS_ON
510 STI
511 .endm
512
513 .macro __BUILD_silent exception
514 .endm
515
516 /* Gas tries to parse the ASM_PRINT argument as a string containing
517 string escapes and emits bogus warnings if it believes to
518 recognize an unknown escape code. So make the arguments
519 start with an n and gas will believe \n is ok ... */
520 .macro __BUILD_verbose nexception
521 LONG_L a1, PT_EPC(sp)
522 #ifdef CONFIG_32BIT
523 ASM_PRINT("Got \nexception at %08lx\012")
524 #endif
525 #ifdef CONFIG_64BIT
526 ASM_PRINT("Got \nexception at %016lx\012")
527 #endif
528 .endm
529
530 .macro __BUILD_count exception
531 LONG_L t0,exception_count_\exception
532 LONG_ADDIU t0, 1
533 LONG_S t0,exception_count_\exception
534 .comm exception_count\exception, 8, 8
535 .endm
536
537 .macro __BUILD_HANDLER exception handler clear verbose ext
538 .align 5
539 NESTED(handle_\exception, PT_SIZE, sp)
540 .cfi_signal_frame
541 .set noat
542 SAVE_ALL
543 FEXPORT(handle_\exception\ext)
544 __build_clear_\clear
545 .set at
546 __BUILD_\verbose \exception
547 move a0, sp
548 jal do_\handler
549 j ret_from_exception
550 END(handle_\exception)
551 .endm
552
553 .macro BUILD_HANDLER exception handler clear verbose
554 __BUILD_HANDLER \exception \handler \clear \verbose _int
555 .endm
556
557 BUILD_HANDLER adel ade ade silent /* #4 */
558 BUILD_HANDLER ades ade ade silent /* #5 */
559 BUILD_HANDLER ibe be cli silent /* #6 */
560 BUILD_HANDLER dbe be cli silent /* #7 */
561 BUILD_HANDLER bp bp sti silent /* #9 */
562 BUILD_HANDLER ri ri sti silent /* #10 */
563 BUILD_HANDLER cpu cpu sti silent /* #11 */
564 BUILD_HANDLER ov ov sti silent /* #12 */
565 BUILD_HANDLER tr tr sti silent /* #13 */
566 BUILD_HANDLER msa_fpe msa_fpe msa_fpe silent /* #14 */
567 #ifdef CONFIG_MIPS_FP_SUPPORT
568 BUILD_HANDLER fpe fpe fpe silent /* #15 */
569 #endif
570 BUILD_HANDLER ftlb ftlb none silent /* #16 */
571 BUILD_HANDLER gsexc gsexc gsexc silent /* #16 */
572 BUILD_HANDLER msa msa sti silent /* #21 */
573 BUILD_HANDLER mdmx mdmx sti silent /* #22 */
574 #ifdef CONFIG_HARDWARE_WATCHPOINTS
575 /*
576 * For watch, interrupts will be enabled after the watch
577 * registers are read.
578 */
579 BUILD_HANDLER watch watch cli silent /* #23 */
580 #else
581 BUILD_HANDLER watch watch sti verbose /* #23 */
582 #endif
583 BUILD_HANDLER mcheck mcheck cli verbose /* #24 */
584 BUILD_HANDLER mt mt sti silent /* #25 */
585 BUILD_HANDLER dsp dsp sti silent /* #26 */
586 BUILD_HANDLER reserved reserved sti verbose /* others */
587
588 .align 5
589 LEAF(handle_ri_rdhwr_tlbp)
590 .set push
591 .set noat
592 .set noreorder
593 /* check if TLB contains a entry for EPC */
594 MFC0 k1, CP0_ENTRYHI
595 andi k1, MIPS_ENTRYHI_ASID | MIPS_ENTRYHI_ASIDX
596 MFC0 k0, CP0_EPC
597 PTR_SRL k0, _PAGE_SHIFT + 1
598 PTR_SLL k0, _PAGE_SHIFT + 1
599 or k1, k0
600 MTC0 k1, CP0_ENTRYHI
601 mtc0_tlbw_hazard
602 tlbp
603 tlb_probe_hazard
604 mfc0 k1, CP0_INDEX
605 .set pop
606 bltz k1, handle_ri /* slow path */
607 /* fall thru */
608 END(handle_ri_rdhwr_tlbp)
609
610 LEAF(handle_ri_rdhwr)
611 .set push
612 .set noat
613 .set noreorder
614 /* MIPS32: 0x7c03e83b: rdhwr v1,$29 */
615 /* microMIPS: 0x007d6b3c: rdhwr v1,$29 */
616 MFC0 k1, CP0_EPC
617 #if defined(CONFIG_CPU_MICROMIPS) || defined(CONFIG_CPU_MIPS32_R2) || defined(CONFIG_CPU_MIPS64_R2)
618 and k0, k1, 1
619 beqz k0, 1f
620 xor k1, k0
621 lhu k0, (k1)
622 lhu k1, 2(k1)
623 ins k1, k0, 16, 16
624 lui k0, 0x007d
625 b docheck
626 ori k0, 0x6b3c
627 1:
628 lui k0, 0x7c03
629 lw k1, (k1)
630 ori k0, 0xe83b
631 #else
632 andi k0, k1, 1
633 bnez k0, handle_ri
634 lui k0, 0x7c03
635 lw k1, (k1)
636 ori k0, 0xe83b
637 #endif
638 .set reorder
639 docheck:
640 bne k0, k1, handle_ri /* if not ours */
641
642 isrdhwr:
643 /* The insn is rdhwr. No need to check CAUSE.BD here. */
644 get_saved_sp /* k1 := current_thread_info */
645 .set noreorder
646 MFC0 k0, CP0_EPC
647 #if defined(CONFIG_CPU_R3000)
648 ori k1, _THREAD_MASK
649 xori k1, _THREAD_MASK
650 LONG_L v1, TI_TP_VALUE(k1)
651 LONG_ADDIU k0, 4
652 jr k0
653 rfe
654 #else
655 #ifndef CONFIG_CPU_DADDI_WORKAROUNDS
656 LONG_ADDIU k0, 4 /* stall on $k0 */
657 #else
658 .set at=v1
659 LONG_ADDIU k0, 4
660 .set noat
661 #endif
662 MTC0 k0, CP0_EPC
663 /* I hope three instructions between MTC0 and ERET are enough... */
664 ori k1, _THREAD_MASK
665 xori k1, _THREAD_MASK
666 LONG_L v1, TI_TP_VALUE(k1)
667 .set push
668 .set arch=r4000
669 eret
670 .set pop
671 #endif
672 .set pop
673 END(handle_ri_rdhwr)
674
675 #ifdef CONFIG_CPU_R4X00_BUGS64
676 /* A temporary overflow handler used by check_daddi(). */
677
678 __INIT
679
680 BUILD_HANDLER daddi_ov daddi_ov none silent /* #12 */
681 #endif
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