1 /* $OpenBSD: locore.S,v 1.18 1998/09/15 10:58:53 pefo Exp $ */
3 * Copyright (c) 1992, 1993
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
7 * Digital Equipment Corporation and Ralph Campbell.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * Copyright (C) 1989 Digital Equipment Corporation.
34 * Permission to use, copy, modify, and distribute this software and
35 * its documentation for any purpose and without fee is hereby granted,
36 * provided that the above copyright notice appears in all copies.
37 * Digital Equipment Corporation makes no representations about the
38 * suitability of this software for any purpose. It is provided "as is"
39 * without express or implied warranty.
41 * from: Header: /sprite/src/kernel/mach/ds3100.md/RCS/loMem.s,
42 * v 1.1 89/07/11 17:55:04 nelson Exp SPRITE (DECWRL)
43 * from: Header: /sprite/src/kernel/mach/ds3100.md/RCS/machAsm.s,
44 * v 9.2 90/01/29 18:00:39 shirriff Exp SPRITE (DECWRL)
45 * from: Header: /sprite/src/kernel/vm/ds3100.md/vmPmaxAsm.s,
46 * v 1.1 89/07/10 14:27:41 nelson Exp SPRITE (DECWRL)
47 * from: @(#)locore.s 8.5 (Berkeley) 1/4/94
48 * JNPR: exception.S,v 1.5 2007/01/08 04:58:37 katta
53 * Contains code that is the first executed at boot time plus
54 * assembly language support routines.
57 #include "opt_cputype.h"
59 #include <machine/asm.h>
60 #include <machine/cpu.h>
61 #include <machine/regnum.h>
62 #include <machine/cpuregs.h>
63 #include <machine/pte.h>
65 #include "opt_cputype.h"
70 * Clear the software-managed bits in a PTE in register pr.
72 #define CLEAR_PTE_SWBITS(pr) \
74 srl pr, 2 # keep bottom 30 bits
76 .set noreorder # Noreorder is default style!
81 #define INTRCNT_COUNT 128
83 /* Pointer size and mask for n64 */
84 #if defined(__mips_n64)
93 *----------------------------------------------------------------------------
97 * Vector code for the TLB-miss exception vector 0x80000000.
99 * This code is copied to the TLB exception vector address to
100 * which the CPU jumps in response to an exception or a TLB miss.
101 * NOTE: This code must be position independent!!!
105 VECTOR(MipsTLBMiss, unknown)
109 MFC0 k0, MIPS_COP_0_BAD_VADDR # get the fault address
111 VECTOR_END(MipsTLBMiss)
114 *----------------------------------------------------------------------------
118 * This is the real TLB Miss Handler code.
119 * 'segbase' points to the base of the segment table for user processes.
121 * Don't check for invalid pte's here. We load them as well and
122 * let the processor trap to load the correct value after service.
123 *----------------------------------------------------------------------------
128 bltz k0, 1f #02: k0<0 -> 1f (kernel fault)
129 PTR_SRL k0, k0, SEGSHIFT - PTRSHIFT #03: k0=seg offset (almost)
132 PTR_L k1, PC_SEGBASE(k1)
133 beqz k1, 2f #05: make sure segbase is not null
134 andi k0, k0, PTRMASK #06: k0=seg offset
135 PTR_ADDU k1, k0, k1 #07: k1=seg entry address
137 PTR_L k1, 0(k1) #08: k1=seg entry
138 MFC0 k0, MIPS_COP_0_BAD_VADDR #09: k0=bad address (again)
139 beq k1, zero, 2f #0a: ==0 -- no page table
141 PTR_SRL k0, PDRSHIFT - PTRSHIFT # k0=VPN
142 andi k0, k0, PTRMASK # k0=pde offset
143 PTR_ADDU k1, k0, k1 # k1=pde entry address
144 PTR_L k1, 0(k1) # k1=pde entry
145 MFC0 k0, MIPS_COP_0_BAD_VADDR # k0=bad address (again)
146 beq k1, zero, 2f # ==0 -- no page table
148 PTR_SRL k0, PAGE_SHIFT - 2 #0b: k0=VPN (aka va>>10)
149 andi k0, k0, 0xff8 #0c: k0=page tab offset
150 PTR_ADDU k1, k1, k0 #0d: k1=pte address
151 lw k0, 0(k1) #0e: k0=lo0 pte
152 lw k1, 4(k1) #0f: k1=lo0 pte
154 MTC0 k0, MIPS_COP_0_TLB_LO0 #12: lo0 is loaded
157 MTC0 k1, MIPS_COP_0_TLB_LO1 #15: lo1 is loaded
159 tlbwr #1a: write to tlb
161 eret #1f: retUrn from exception
162 1: j MipsTLBMissException #20: kernel exception
163 nop #21: branch delay slot
164 2: j SlowFault #22: no page table present
165 nop #23: branch delay slot
169 * This code is copied to the general exception vector address to
170 * handle all execptions except RESET and TLBMiss.
171 * NOTE: This code must be position independent!!!
173 VECTOR(MipsException, unknown)
175 * Find out what mode we came from and jump to the proper handler.
178 mfc0 k0, MIPS_COP_0_STATUS # Get the status register
179 mfc0 k1, MIPS_COP_0_CAUSE # Get the cause register value.
180 and k0, k0, SR_KSU_USER # test for user mode
181 # sneaky but the bits are
183 sll k0, k0, 3 # shift user bit for cause index
184 and k1, k1, MIPS3_CR_EXC_CODE # Mask out the cause bits.
185 or k1, k1, k0 # change index to user table
186 #if defined(__mips_n64)
187 PTR_SLL k1, k1, 1 # shift to get 8-byte offset
190 PTR_LA k0, _C_LABEL(machExceptionTable) # get base of the jump table
191 PTR_ADDU k0, k0, k1 # Get the address of the
192 # function entry. Note that
193 # the cause is already
194 # shifted left by 2 bits so
195 # we dont have to shift.
196 PTR_L k0, 0(k0) # Get the function address
198 j k0 # Jump to the function.
201 VECTOR_END(MipsException)
204 * We couldn't find a TLB entry.
205 * Find out what mode we came from and call the appropriate handler.
209 mfc0 k0, MIPS_COP_0_STATUS
211 and k0, k0, SR_KSU_USER
212 bne k0, zero, _C_LABEL(MipsUserGenException)
219 /*----------------------------------------------------------------------------
221 * MipsKernGenException --
223 * Handle an exception from kernel mode.
231 *----------------------------------------------------------------------------
234 #define SAVE_REG(reg, offs, base) \
235 REG_S reg, CALLFRAME_SIZ + (SZREG * offs) (base)
237 #if defined(CPU_CNMIPS)
238 #define CLEAR_STATUS \
239 mfc0 a0, MIPS_COP_0_STATUS ;\
240 li a2, (MIPS_SR_KX | MIPS_SR_SX | MIPS_SR_UX) ; \
242 li a2, ~(MIPS_SR_INT_IE | MIPS_SR_EXL | SR_KSU_USER) ; \
244 mtc0 a0, MIPS_COP_0_STATUS ; \
246 #elif defined(CPU_RMI)
247 #define CLEAR_STATUS \
248 mfc0 a0, MIPS_COP_0_STATUS ;\
249 li a2, (MIPS_SR_KX | MIPS_SR_UX | MIPS_SR_COP_2_BIT) ; \
251 li a2, ~(MIPS_SR_INT_IE | MIPS_SR_EXL | SR_KSU_USER) ; \
253 mtc0 a0, MIPS_COP_0_STATUS ; \
256 #define CLEAR_STATUS \
257 mfc0 a0, MIPS_COP_0_STATUS ;\
258 li a2, ~(MIPS_SR_INT_IE | MIPS_SR_EXL | SR_KSU_USER) ; \
260 mtc0 a0, MIPS_COP_0_STATUS ; \
265 * Save CPU and CP0 register state.
267 * This is straightforward except for saving the exception program
268 * counter. The ddb backtrace code looks for the first instruction
269 * matching the form "sw ra, (off)sp" to figure out the address of the
270 * calling function. So we must make sure that we save the exception
271 * PC by staging it through 'ra' as opposed to any other register.
274 SAVE_REG(AT, AST, sp) ;\
276 SAVE_REG(v0, V0, sp) ;\
277 SAVE_REG(v1, V1, sp) ;\
278 SAVE_REG(a0, A0, sp) ;\
279 SAVE_REG(a1, A1, sp) ;\
280 SAVE_REG(a2, A2, sp) ;\
281 SAVE_REG(a3, A3, sp) ;\
282 SAVE_REG(t0, T0, sp) ;\
283 SAVE_REG(t1, T1, sp) ;\
284 SAVE_REG(t2, T2, sp) ;\
285 SAVE_REG(t3, T3, sp) ;\
286 SAVE_REG(ta0, TA0, sp) ;\
287 SAVE_REG(ta1, TA1, sp) ;\
288 SAVE_REG(ta2, TA2, sp) ;\
289 SAVE_REG(ta3, TA3, sp) ;\
290 SAVE_REG(t8, T8, sp) ;\
291 SAVE_REG(t9, T9, sp) ;\
292 SAVE_REG(gp, GP, sp) ;\
293 SAVE_REG(s0, S0, sp) ;\
294 SAVE_REG(s1, S1, sp) ;\
295 SAVE_REG(s2, S2, sp) ;\
296 SAVE_REG(s3, S3, sp) ;\
297 SAVE_REG(s4, S4, sp) ;\
298 SAVE_REG(s5, S5, sp) ;\
299 SAVE_REG(s6, S6, sp) ;\
300 SAVE_REG(s7, S7, sp) ;\
301 SAVE_REG(s8, S8, sp) ;\
304 mfc0 a0, MIPS_COP_0_STATUS ;\
305 mfc0 a1, MIPS_COP_0_CAUSE ;\
306 MFC0 a2, MIPS_COP_0_BAD_VADDR;\
307 MFC0 a3, MIPS_COP_0_EXC_PC ;\
308 SAVE_REG(v0, MULLO, sp) ;\
309 SAVE_REG(v1, MULHI, sp) ;\
310 SAVE_REG(a0, SR, sp) ;\
311 SAVE_REG(a1, CAUSE, sp) ;\
312 SAVE_REG(a2, BADVADDR, sp) ;\
315 SAVE_REG(ra, PC, sp) ;\
317 SAVE_REG(ra, RA, sp) ;\
318 PTR_ADDU v0, sp, KERN_EXC_FRAME_SIZE ;\
319 SAVE_REG(v0, SP, sp) ;\
321 PTR_ADDU a0, sp, CALLFRAME_SIZ ;\
324 #define RESTORE_REG(reg, offs, base) \
325 REG_L reg, CALLFRAME_SIZ + (SZREG * offs) (base)
327 #define RESTORE_CPU \
329 RESTORE_REG(k0, SR, sp) ;\
330 RESTORE_REG(t0, MULLO, sp) ;\
331 RESTORE_REG(t1, MULHI, sp) ;\
334 MTC0 v0, MIPS_COP_0_EXC_PC ;\
336 RESTORE_REG(AT, AST, sp) ;\
337 RESTORE_REG(v0, V0, sp) ;\
338 RESTORE_REG(v1, V1, sp) ;\
339 RESTORE_REG(a0, A0, sp) ;\
340 RESTORE_REG(a1, A1, sp) ;\
341 RESTORE_REG(a2, A2, sp) ;\
342 RESTORE_REG(a3, A3, sp) ;\
343 RESTORE_REG(t0, T0, sp) ;\
344 RESTORE_REG(t1, T1, sp) ;\
345 RESTORE_REG(t2, T2, sp) ;\
346 RESTORE_REG(t3, T3, sp) ;\
347 RESTORE_REG(ta0, TA0, sp) ;\
348 RESTORE_REG(ta1, TA1, sp) ;\
349 RESTORE_REG(ta2, TA2, sp) ;\
350 RESTORE_REG(ta3, TA3, sp) ;\
351 RESTORE_REG(t8, T8, sp) ;\
352 RESTORE_REG(t9, T9, sp) ;\
353 RESTORE_REG(s0, S0, sp) ;\
354 RESTORE_REG(s1, S1, sp) ;\
355 RESTORE_REG(s2, S2, sp) ;\
356 RESTORE_REG(s3, S3, sp) ;\
357 RESTORE_REG(s4, S4, sp) ;\
358 RESTORE_REG(s5, S5, sp) ;\
359 RESTORE_REG(s6, S6, sp) ;\
360 RESTORE_REG(s7, S7, sp) ;\
361 RESTORE_REG(s8, S8, sp) ;\
362 RESTORE_REG(gp, GP, sp) ;\
363 RESTORE_REG(ra, RA, sp) ;\
364 PTR_ADDU sp, sp, KERN_EXC_FRAME_SIZE;\
365 mtc0 k0, MIPS_COP_0_STATUS
369 * The kernel exception stack contains 18 saved general registers,
370 * the status register and the multiply lo and high registers.
371 * In addition, we set this up for linkage conventions.
373 #define KERN_REG_SIZE (NUMSAVEREGS * SZREG)
374 #define KERN_EXC_FRAME_SIZE (CALLFRAME_SIZ + KERN_REG_SIZE + 16)
376 NNON_LEAF(MipsKernGenException, KERN_EXC_FRAME_SIZE, ra)
378 PTR_SUBU sp, sp, KERN_EXC_FRAME_SIZE
379 .mask 0x80000000, (CALLFRAME_RA - KERN_EXC_FRAME_SIZE)
381 * Save CPU state, building 'frame'.
385 * Call the exception handler. a0 points at the saved frame.
387 PTR_LA gp, _C_LABEL(_gp)
388 PTR_LA k0, _C_LABEL(trap)
390 REG_S a3, CALLFRAME_RA + KERN_REG_SIZE(sp) # for debugging
393 * Update interrupt mask in saved status register
394 * Some of interrupts could be disabled by
395 * intr filters if interrupts are enabled later
398 mfc0 a0, MIPS_COP_0_STATUS
399 and a0, a0, MIPS_SR_INT_MASK
400 RESTORE_REG(a1, SR, sp)
401 and a1, a1, ~MIPS_SR_INT_MASK
404 RESTORE_CPU # v0 contains the return address.
408 END(MipsKernGenException)
411 #define SAVE_U_PCB_REG(reg, offs, base) \
412 REG_S reg, U_PCB_REGS + (SZREG * offs) (base)
414 #define RESTORE_U_PCB_REG(reg, offs, base) \
415 REG_L reg, U_PCB_REGS + (SZREG * offs) (base)
417 /*----------------------------------------------------------------------------
419 * MipsUserGenException --
421 * Handle an exception from user mode.
429 *----------------------------------------------------------------------------
431 NNON_LEAF(MipsUserGenException, CALLFRAME_SIZ, ra)
433 .mask 0x80000000, (CALLFRAME_RA - CALLFRAME_SIZ)
435 * Save all of the registers except for the kernel temporaries in u.u_pcb.
438 PTR_L k1, PC_CURPCB(k1)
439 SAVE_U_PCB_REG(AT, AST, k1)
441 SAVE_U_PCB_REG(v0, V0, k1)
442 SAVE_U_PCB_REG(v1, V1, k1)
443 SAVE_U_PCB_REG(a0, A0, k1)
445 SAVE_U_PCB_REG(a1, A1, k1)
446 SAVE_U_PCB_REG(a2, A2, k1)
447 SAVE_U_PCB_REG(a3, A3, k1)
448 SAVE_U_PCB_REG(t0, T0, k1)
450 SAVE_U_PCB_REG(t1, T1, k1)
451 SAVE_U_PCB_REG(t2, T2, k1)
452 SAVE_U_PCB_REG(t3, T3, k1)
453 SAVE_U_PCB_REG(ta0, TA0, k1)
454 mfc0 a0, MIPS_COP_0_STATUS # First arg is the status reg.
455 SAVE_U_PCB_REG(ta1, TA1, k1)
456 SAVE_U_PCB_REG(ta2, TA2, k1)
457 SAVE_U_PCB_REG(ta3, TA3, k1)
458 SAVE_U_PCB_REG(s0, S0, k1)
459 mfc0 a1, MIPS_COP_0_CAUSE # Second arg is the cause reg.
460 SAVE_U_PCB_REG(s1, S1, k1)
461 SAVE_U_PCB_REG(s2, S2, k1)
462 SAVE_U_PCB_REG(s3, S3, k1)
463 SAVE_U_PCB_REG(s4, S4, k1)
464 MFC0 a2, MIPS_COP_0_BAD_VADDR # Third arg is the fault addr
465 SAVE_U_PCB_REG(s5, S5, k1)
466 SAVE_U_PCB_REG(s6, S6, k1)
467 SAVE_U_PCB_REG(s7, S7, k1)
468 SAVE_U_PCB_REG(t8, T8, k1)
469 MFC0 a3, MIPS_COP_0_EXC_PC # Fourth arg is the pc.
470 SAVE_U_PCB_REG(t9, T9, k1)
471 SAVE_U_PCB_REG(gp, GP, k1)
472 SAVE_U_PCB_REG(sp, SP, k1)
473 SAVE_U_PCB_REG(s8, S8, k1)
474 PTR_SUBU sp, k1, CALLFRAME_SIZ # switch to kernel SP
475 SAVE_U_PCB_REG(ra, RA, k1)
476 SAVE_U_PCB_REG(v0, MULLO, k1)
477 SAVE_U_PCB_REG(v1, MULHI, k1)
478 SAVE_U_PCB_REG(a0, SR, k1)
479 SAVE_U_PCB_REG(a1, CAUSE, k1)
480 SAVE_U_PCB_REG(a2, BADVADDR, k1)
481 SAVE_U_PCB_REG(a3, PC, k1)
482 REG_S a3, CALLFRAME_RA(sp) # for debugging
483 PTR_LA gp, _C_LABEL(_gp) # switch to kernel GP
484 # Turn off fpu and enter kernel mode
485 and t0, a0, ~(MIPS_SR_COP_1_BIT | MIPS_SR_EXL | MIPS3_SR_KSU_MASK | MIPS_SR_INT_IE)
486 #if defined(CPU_CNMIPS)
487 or t0, t0, (MIPS_SR_KX | MIPS_SR_SX | MIPS_SR_UX | MIPS_SR_PX)
488 #elif defined(CPU_RMI)
489 or t0, t0, (MIPS_SR_KX | MIPS_SR_UX | MIPS_SR_COP_2_BIT)
491 mtc0 t0, MIPS_COP_0_STATUS
492 PTR_ADDU a0, k1, U_PCB_REGS
496 * Call the exception handler.
498 PTR_LA k0, _C_LABEL(trap)
503 * Restore user registers and return.
504 * First disable interrupts and set exeption level.
511 * The use of k1 for storing the PCB pointer must be done only
512 * after interrupts are disabled. Otherwise it will get overwritten
513 * by the interrupt code.
516 PTR_L k1, PC_CURPCB(k1)
519 * Update interrupt mask in saved status register
520 * Some of interrupts could be enabled by ithread
523 mfc0 a0, MIPS_COP_0_STATUS
524 and a0, a0, MIPS_SR_INT_MASK
525 RESTORE_U_PCB_REG(a1, SR, k1)
526 and a1, a1, ~MIPS_SR_INT_MASK
528 SAVE_U_PCB_REG(a1, SR, k1)
530 RESTORE_U_PCB_REG(t0, MULLO, k1)
531 RESTORE_U_PCB_REG(t1, MULHI, k1)
534 RESTORE_U_PCB_REG(a0, PC, k1)
535 RESTORE_U_PCB_REG(v0, V0, k1)
536 MTC0 a0, MIPS_COP_0_EXC_PC # set return address
537 RESTORE_U_PCB_REG(v1, V1, k1)
538 RESTORE_U_PCB_REG(a0, A0, k1)
539 RESTORE_U_PCB_REG(a1, A1, k1)
540 RESTORE_U_PCB_REG(a2, A2, k1)
541 RESTORE_U_PCB_REG(a3, A3, k1)
542 RESTORE_U_PCB_REG(t0, T0, k1)
543 RESTORE_U_PCB_REG(t1, T1, k1)
544 RESTORE_U_PCB_REG(t2, T2, k1)
545 RESTORE_U_PCB_REG(t3, T3, k1)
546 RESTORE_U_PCB_REG(ta0, TA0, k1)
547 RESTORE_U_PCB_REG(ta1, TA1, k1)
548 RESTORE_U_PCB_REG(ta2, TA2, k1)
549 RESTORE_U_PCB_REG(ta3, TA3, k1)
550 RESTORE_U_PCB_REG(s0, S0, k1)
551 RESTORE_U_PCB_REG(s1, S1, k1)
552 RESTORE_U_PCB_REG(s2, S2, k1)
553 RESTORE_U_PCB_REG(s3, S3, k1)
554 RESTORE_U_PCB_REG(s4, S4, k1)
555 RESTORE_U_PCB_REG(s5, S5, k1)
556 RESTORE_U_PCB_REG(s6, S6, k1)
557 RESTORE_U_PCB_REG(s7, S7, k1)
558 RESTORE_U_PCB_REG(t8, T8, k1)
559 RESTORE_U_PCB_REG(t9, T9, k1)
560 RESTORE_U_PCB_REG(gp, GP, k1)
561 RESTORE_U_PCB_REG(sp, SP, k1)
562 RESTORE_U_PCB_REG(k0, SR, k1)
563 RESTORE_U_PCB_REG(s8, S8, k1)
564 RESTORE_U_PCB_REG(ra, RA, k1)
566 RESTORE_U_PCB_REG(AT, AST, k1)
568 mtc0 k0, MIPS_COP_0_STATUS # still exception level
573 END(MipsUserGenException)
575 /*----------------------------------------------------------------------------
579 * Handle an interrupt from kernel mode.
580 * Interrupts use the standard kernel stack.
581 * switch_exit sets up a kernel stack after exit so interrupts won't fail.
589 *----------------------------------------------------------------------------
592 NNON_LEAF(MipsKernIntr, KERN_EXC_FRAME_SIZE, ra)
594 PTR_SUBU sp, sp, KERN_EXC_FRAME_SIZE
595 .mask 0x80000000, (CALLFRAME_RA - KERN_EXC_FRAME_SIZE)
597 * Save CPU state, building 'frame'.
601 * Call the interrupt handler. a0 points at the saved frame.
603 PTR_LA gp, _C_LABEL(_gp)
604 PTR_LA k0, _C_LABEL(cpu_intr)
606 REG_S a3, CALLFRAME_RA + KERN_REG_SIZE(sp) # for debugging
609 * Update interrupt mask in saved status register
610 * Some of interrupts could be disabled by
611 * intr filters if interrupts are enabled later
614 mfc0 a0, MIPS_COP_0_STATUS
615 and a0, a0, MIPS_SR_INT_MASK
616 RESTORE_REG(a1, SR, sp)
617 and a1, a1, ~MIPS_SR_INT_MASK
620 REG_L v0, CALLFRAME_RA + KERN_REG_SIZE(sp)
621 RESTORE_CPU # v0 contains the return address.
627 /*----------------------------------------------------------------------------
631 * Handle an interrupt from user mode.
632 * Note: we save minimal state in the u.u_pcb struct and use the standard
633 * kernel stack since there has to be a u page if we came from user mode.
634 * If there is a pending software interrupt, then save the remaining state
635 * and call softintr(). This is all because if we call switch() inside
636 * interrupt(), not all the user registers have been saved in u.u_pcb.
644 *----------------------------------------------------------------------------
646 NNON_LEAF(MipsUserIntr, CALLFRAME_SIZ, ra)
648 .mask 0x80000000, (CALLFRAME_RA - CALLFRAME_SIZ)
650 * Save the relevant user registers into the u.u_pcb struct.
651 * We don't need to save s0 - s8 because the compiler does it for us.
654 PTR_L k1, PC_CURPCB(k1)
655 SAVE_U_PCB_REG(AT, AST, k1)
657 SAVE_U_PCB_REG(v0, V0, k1)
658 SAVE_U_PCB_REG(v1, V1, k1)
659 SAVE_U_PCB_REG(a0, A0, k1)
660 SAVE_U_PCB_REG(a1, A1, k1)
661 SAVE_U_PCB_REG(a2, A2, k1)
662 SAVE_U_PCB_REG(a3, A3, k1)
663 SAVE_U_PCB_REG(t0, T0, k1)
664 SAVE_U_PCB_REG(t1, T1, k1)
665 SAVE_U_PCB_REG(t2, T2, k1)
666 SAVE_U_PCB_REG(t3, T3, k1)
667 SAVE_U_PCB_REG(ta0, TA0, k1)
668 SAVE_U_PCB_REG(ta1, TA1, k1)
669 SAVE_U_PCB_REG(ta2, TA2, k1)
670 SAVE_U_PCB_REG(ta3, TA3, k1)
671 SAVE_U_PCB_REG(t8, T8, k1)
672 SAVE_U_PCB_REG(t9, T9, k1)
673 SAVE_U_PCB_REG(gp, GP, k1)
674 SAVE_U_PCB_REG(sp, SP, k1)
675 SAVE_U_PCB_REG(ra, RA, k1)
677 * save remaining user state in u.u_pcb.
679 SAVE_U_PCB_REG(s0, S0, k1)
680 SAVE_U_PCB_REG(s1, S1, k1)
681 SAVE_U_PCB_REG(s2, S2, k1)
682 SAVE_U_PCB_REG(s3, S3, k1)
683 SAVE_U_PCB_REG(s4, S4, k1)
684 SAVE_U_PCB_REG(s5, S5, k1)
685 SAVE_U_PCB_REG(s6, S6, k1)
686 SAVE_U_PCB_REG(s7, S7, k1)
687 SAVE_U_PCB_REG(s8, S8, k1)
689 mflo v0 # get lo/hi late to avoid stall
691 mfc0 a0, MIPS_COP_0_STATUS
692 mfc0 a1, MIPS_COP_0_CAUSE
693 MFC0 a3, MIPS_COP_0_EXC_PC
694 SAVE_U_PCB_REG(v0, MULLO, k1)
695 SAVE_U_PCB_REG(v1, MULHI, k1)
696 SAVE_U_PCB_REG(a0, SR, k1)
697 SAVE_U_PCB_REG(a1, CAUSE, k1)
698 SAVE_U_PCB_REG(a3, PC, k1) # PC in a3, note used later!
699 PTR_SUBU sp, k1, CALLFRAME_SIZ # switch to kernel SP
700 PTR_LA gp, _C_LABEL(_gp) # switch to kernel GP
702 # Turn off fpu, disable interrupts, set kernel mode kernel mode, clear exception level.
703 and t0, a0, ~(MIPS_SR_COP_1_BIT | MIPS_SR_EXL | MIPS_SR_INT_IE | MIPS3_SR_KSU_MASK)
705 or t0, t0, (MIPS_SR_KX | MIPS_SR_SX | MIPS_SR_UX | MIPS_SR_PX)
706 #elif defined(CPU_RMI)
707 or t0, t0, (MIPS_SR_KX | MIPS_SR_UX | MIPS_SR_COP_2_BIT)
709 mtc0 t0, MIPS_COP_0_STATUS
711 PTR_ADDU a0, k1, U_PCB_REGS
713 * Call the interrupt handler.
715 PTR_LA k0, _C_LABEL(cpu_intr)
717 REG_S a3, CALLFRAME_RA(sp) # for debugging
720 * Enable interrupts before doing ast().
722 * On SMP kernels the AST processing might trigger IPI to other processors.
723 * If that processor is also doing AST processing with interrupts disabled
724 * then we may deadlock.
726 mfc0 a0, MIPS_COP_0_STATUS
727 or a0, a0, MIPS_SR_INT_IE
728 mtc0 a0, MIPS_COP_0_STATUS
732 * DO_AST enabled interrupts
737 * Restore user registers and return.
742 PTR_L k1, PC_CURPCB(k1)
745 * Update interrupt mask in saved status register
746 * Some of interrupts could be disabled by
749 mfc0 a0, MIPS_COP_0_STATUS
750 and a0, a0, MIPS_SR_INT_MASK
751 RESTORE_U_PCB_REG(a1, SR, k1)
752 and a1, a1, ~MIPS_SR_INT_MASK
754 SAVE_U_PCB_REG(a1, SR, k1)
756 RESTORE_U_PCB_REG(s0, S0, k1)
757 RESTORE_U_PCB_REG(s1, S1, k1)
758 RESTORE_U_PCB_REG(s2, S2, k1)
759 RESTORE_U_PCB_REG(s3, S3, k1)
760 RESTORE_U_PCB_REG(s4, S4, k1)
761 RESTORE_U_PCB_REG(s5, S5, k1)
762 RESTORE_U_PCB_REG(s6, S6, k1)
763 RESTORE_U_PCB_REG(s7, S7, k1)
764 RESTORE_U_PCB_REG(s8, S8, k1)
765 RESTORE_U_PCB_REG(t0, MULLO, k1)
766 RESTORE_U_PCB_REG(t1, MULHI, k1)
767 RESTORE_U_PCB_REG(t2, PC, k1)
770 MTC0 t2, MIPS_COP_0_EXC_PC # set return address
771 RESTORE_U_PCB_REG(v0, V0, k1)
772 RESTORE_U_PCB_REG(v1, V1, k1)
773 RESTORE_U_PCB_REG(a0, A0, k1)
774 RESTORE_U_PCB_REG(a1, A1, k1)
775 RESTORE_U_PCB_REG(a2, A2, k1)
776 RESTORE_U_PCB_REG(a3, A3, k1)
777 RESTORE_U_PCB_REG(t0, T0, k1)
778 RESTORE_U_PCB_REG(t1, T1, k1)
779 RESTORE_U_PCB_REG(t2, T2, k1)
780 RESTORE_U_PCB_REG(t3, T3, k1)
781 RESTORE_U_PCB_REG(ta0, TA0, k1)
782 RESTORE_U_PCB_REG(ta1, TA1, k1)
783 RESTORE_U_PCB_REG(ta2, TA2, k1)
784 RESTORE_U_PCB_REG(ta3, TA3, k1)
785 RESTORE_U_PCB_REG(t8, T8, k1)
786 RESTORE_U_PCB_REG(t9, T9, k1)
787 RESTORE_U_PCB_REG(gp, GP, k1)
788 RESTORE_U_PCB_REG(k0, SR, k1)
789 RESTORE_U_PCB_REG(sp, SP, k1)
790 RESTORE_U_PCB_REG(ra, RA, k1)
792 RESTORE_U_PCB_REG(AT, AST, k1)
794 mtc0 k0, MIPS_COP_0_STATUS # SR with EXL set.
801 NLEAF(MipsTLBInvalidException)
806 MFC0 k0, MIPS_COP_0_BAD_VADDR
807 PTR_LI k1, VM_MAXUSER_ADDRESS
812 /* Kernel address. */
813 lui k1, %hi(kernel_segmap) # k1=hi of segbase
815 PTR_L k1, %lo(kernel_segmap)(k1) # k1=segment tab base
817 1: /* User address. */
819 PTR_L k1, PC_SEGBASE(k1)
821 2: /* Validate page directory pointer. */
825 PTR_SRL k0, SEGSHIFT - PTRSHIFT # k0=seg offset (almost)
826 beq k1, zero, MipsKernGenException # ==0 -- no seg tab
827 andi k0, k0, PTRMASK # k0=seg offset
828 PTR_ADDU k1, k0, k1 # k1=seg entry address
829 PTR_L k1, 0(k1) # k1=seg entry
831 /* Validate page table pointer. */
836 MFC0 k0, MIPS_COP_0_BAD_VADDR
837 PTR_SRL k0, PDRSHIFT - PTRSHIFT # k0=pde offset (almost)
838 beq k1, zero, MipsKernGenException # ==0 -- no pde tab
839 andi k0, k0, PTRMASK # k0=pde offset
840 PTR_ADDU k1, k0, k1 # k1=pde entry address
841 PTR_L k1, 0(k1) # k1=pde entry
843 /* Validate pde table pointer. */
847 MFC0 k0, MIPS_COP_0_BAD_VADDR # k0=bad address (again)
848 PTR_SRL k0, PAGE_SHIFT - 2 # k0=VPN
849 andi k0, k0, 0xffc # k0=page tab offset
850 PTR_ADDU k1, k1, k0 # k1=pte address
851 lw k0, 0(k1) # k0=this PTE
853 /* Validate page table entry. */
858 /* Check whether this is an even or odd entry. */
866 MTC0 k0, MIPS_COP_0_TLB_LO0
869 MTC0 k1, MIPS_COP_0_TLB_LO1
879 MTC0 k0, MIPS_COP_0_TLB_LO0
882 MTC0 k1, MIPS_COP_0_TLB_LO1
888 mfc0 k0, MIPS_COP_0_TLB_INDEX
889 bltz k0, tlb_insert_random
902 * Branch to the comprehensive exception processing.
904 mfc0 k1, MIPS_COP_0_STATUS
905 andi k1, k1, SR_KSU_USER
906 bnez k1, _C_LABEL(MipsUserGenException)
910 * Check for kernel stack overflow.
913 PTR_L k0, PC_CURTHREAD(k1)
914 PTR_L k0, TD_KSTACK(k0)
916 bnez k0, _C_LABEL(MipsKernGenException)
920 * Kernel stack overflow.
922 * Move to a valid stack before we call panic. We use the boot stack
927 sll k1, k1, PAGE_SHIFT + 1
929 PTR_LA k0, _C_LABEL(pcpu_space)
930 PTR_ADDU k0, PAGE_SIZE * 2
934 * Stash the original value of 'sp' so we can update trapframe later.
935 * We assume that SAVE_CPU does not trash 'k1'.
940 PTR_SUBU sp, sp, KERN_EXC_FRAME_SIZE
944 REG_S ra, CALLFRAME_RA(sp) /* stop the ddb backtrace right here */
945 REG_S zero, CALLFRAME_SP(sp)
951 * Now restore the value of 'sp' at the time of the tlb exception in
957 * Squelch any more overflow checks by setting the stack base to 0.
960 PTR_L k0, PC_CURTHREAD(k1)
961 PTR_S zero, TD_KSTACK(k0)
964 PANIC("kernel stack overflow - trapframe at %p")
967 * This nop is necessary so that the 'ra' remains within the bounds
968 * of this handler. Otherwise the ddb backtrace code will think that
969 * the panic() was called from MipsTLBMissException.
974 END(MipsTLBInvalidException)
976 /*----------------------------------------------------------------------------
978 * MipsTLBMissException --
980 * Handle a TLB miss exception from kernel mode in kernel space.
981 * The BaddVAddr, Context, and EntryHi registers contain the failed
990 *----------------------------------------------------------------------------
992 NLEAF(MipsTLBMissException)
994 MFC0 k0, MIPS_COP_0_BAD_VADDR # k0=bad address
995 PTR_LI k1, VM_MAX_KERNEL_ADDRESS # check fault address against
996 sltu k1, k1, k0 # upper bound of kernel_segmap
997 bnez k1, MipsKernGenException # out of bound
998 lui k1, %hi(kernel_segmap) # k1=hi of segbase
999 PTR_SRL k0, SEGSHIFT - PTRSHIFT # k0=seg offset (almost)
1000 PTR_L k1, %lo(kernel_segmap)(k1) # k1=segment tab base
1001 beq k1, zero, MipsKernGenException # ==0 -- no seg tab
1002 andi k0, k0, PTRMASK # k0=seg offset
1003 PTR_ADDU k1, k0, k1 # k1=seg entry address
1004 PTR_L k1, 0(k1) # k1=seg entry
1005 MFC0 k0, MIPS_COP_0_BAD_VADDR # k0=bad address (again)
1006 beq k1, zero, MipsKernGenException # ==0 -- no page table
1008 PTR_SRL k0, PDRSHIFT - PTRSHIFT # k0=VPN
1009 andi k0, k0, PTRMASK # k0=pde offset
1010 PTR_ADDU k1, k0, k1 # k1=pde entry address
1011 PTR_L k1, 0(k1) # k1=pde entry
1012 MFC0 k0, MIPS_COP_0_BAD_VADDR # k0=bad address (again)
1013 beq k1, zero, MipsKernGenException # ==0 -- no page table
1015 PTR_SRL k0, PAGE_SHIFT - 2 # k0=VPN
1016 andi k0, k0, 0xff8 # k0=page tab offset
1017 PTR_ADDU k1, k1, k0 # k1=pte address
1018 lw k0, 0(k1) # k0=lo0 pte
1019 lw k1, 4(k1) # k1=lo1 pte
1020 CLEAR_PTE_SWBITS(k0)
1021 MTC0 k0, MIPS_COP_0_TLB_LO0 # lo0 is loaded
1023 CLEAR_PTE_SWBITS(k1)
1024 MTC0 k1, MIPS_COP_0_TLB_LO1 # lo1 is loaded
1026 tlbwr # write to tlb
1028 eret # return from exception
1030 END(MipsTLBMissException)
1032 /*----------------------------------------------------------------------------
1036 * Handle a floating point Trap.
1038 * MipsFPTrap(statusReg, causeReg, pc)
1039 * unsigned statusReg;
1040 * unsigned causeReg;
1049 *----------------------------------------------------------------------------
1051 NON_LEAF(MipsFPTrap, CALLFRAME_SIZ, ra)
1052 PTR_SUBU sp, sp, CALLFRAME_SIZ
1053 mfc0 t0, MIPS_COP_0_STATUS
1054 REG_S ra, CALLFRAME_RA(sp)
1055 .mask 0x80000000, (CALLFRAME_RA - CALLFRAME_SIZ)
1057 or t1, t0, MIPS_SR_COP_1_BIT
1058 mtc0 t1, MIPS_COP_0_STATUS
1060 cfc1 t1, MIPS_FPU_CSR # stall til FP done
1061 cfc1 t1, MIPS_FPU_CSR # now get status
1063 sll t2, t1, (31 - 17) # unimplemented operation?
1064 bgez t2, 3f # no, normal trap
1067 * We got an unimplemented operation trap so
1068 * fetch the instruction, compute the next PC and emulate the instruction.
1070 bgez a1, 1f # Check the branch delay bit.
1073 * The instruction is in the branch delay slot so the branch will have to
1074 * be emulated to get the resulting PC.
1076 PTR_S a2, CALLFRAME_SIZ + 8(sp)
1079 PTR_L a0, PC_CURPCB(a0)
1080 PTR_ADDU a0, a0, U_PCB_REGS # first arg is ptr to CPU registers
1081 move a1, a2 # second arg is instruction PC
1082 move a2, t1 # third arg is floating point CSR
1083 PTR_LA t3, _C_LABEL(MipsEmulateBranch) # compute PC after branch
1084 jalr t3 # compute PC after branch
1085 move a3, zero # fourth arg is FALSE
1087 * Now load the floating-point instruction in the branch delay slot
1090 PTR_L a2, CALLFRAME_SIZ + 8(sp) # restore EXC pc
1092 lw a0, 4(a2) # a0 = coproc instruction
1094 * This is not in the branch delay slot so calculate the resulting
1095 * PC (epc + 4) into v0 and continue to MipsEmulateFP().
1098 lw a0, 0(a2) # a0 = coproc instruction
1100 PTR_ADDU v0, a2, 4 # v0 = next pc
1103 PTR_L t2, PC_CURPCB(t2)
1104 SAVE_U_PCB_REG(v0, PC, t2) # save new pc
1106 * Check to see if the instruction to be emulated is a floating-point
1109 srl a3, a0, MIPS_OPCODE_SHIFT
1110 beq a3, MIPS_OPCODE_C1, 4f # this should never fail
1113 * Send a floating point exception signal to the current process.
1117 PTR_L a0, PC_CURTHREAD(a0) # get current thread
1118 cfc1 a2, MIPS_FPU_CSR # code = FP execptions
1119 ctc1 zero, MIPS_FPU_CSR # Clear exceptions
1120 PTR_LA t3, _C_LABEL(trapsignal)
1127 * Finally, we can call MipsEmulateFP() where a0 is the instruction to emulate.
1130 PTR_LA t3, _C_LABEL(MipsEmulateFP)
1135 * Turn off the floating point coprocessor and return.
1138 mfc0 t0, MIPS_COP_0_STATUS
1139 PTR_L ra, CALLFRAME_RA(sp)
1140 and t0, t0, ~MIPS_SR_COP_1_BIT
1141 mtc0 t0, MIPS_COP_0_STATUS
1144 PTR_ADDU sp, sp, CALLFRAME_SIZ
1148 * Interrupt counters for vmstat.
1156 .space INTRCNT_COUNT * (MAXCOMLEN + 1) * 2
1160 .space INTRCNT_COUNT * 4 * 2
1165 * Vector to real handler in KSEG1.
1168 VECTOR(MipsCache, unknown)
1169 PTR_LA k0, _C_LABEL(MipsCacheException)
1170 li k1, MIPS_KSEG0_PHYS_MASK
1172 PTR_LI k1, MIPS_KSEG1_START
1176 VECTOR_END(MipsCache)
1182 * Panic on cache errors. A lot more could be done to recover
1183 * from some types of errors but it is tricky.
1185 NESTED_NOPROFILE(MipsCacheException, KERN_EXC_FRAME_SIZE, ra)
1187 .mask 0x80000000, -4
1188 PTR_LA k0, _C_LABEL(panic) # return to panic
1189 PTR_LA a0, 9f # panicstr
1190 MFC0 a1, MIPS_COP_0_ERROR_PC
1191 mfc0 a2, MIPS_COP_0_CACHE_ERR # 3rd arg cache error
1193 MTC0 k0, MIPS_COP_0_ERROR_PC # set return address
1195 mfc0 k0, MIPS_COP_0_STATUS # restore status
1196 li k1, MIPS_SR_DIAG_PE # ignore further errors
1198 mtc0 k0, MIPS_COP_0_STATUS # restore status
1203 MSG("cache error @ EPC 0x%x CachErr 0x%x");
1205 END(MipsCacheException)