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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) 1996, 97, 2000, 2001 by Ralf Baechle
7 * Copyright (C) 2001 MIPS Technologies, Inc.
8 */
9#include <linux/kernel.h>
10#include <linux/sched/signal.h>
11#include <linux/signal.h>
12#include <linux/export.h>
13#include <asm/branch.h>
14#include <asm/cpu.h>
15#include <asm/cpu-features.h>
16#include <asm/fpu.h>
17#include <asm/fpu_emulator.h>
18#include <asm/inst.h>
19#include <asm/mips-r2-to-r6-emul.h>
20#include <asm/ptrace.h>
21#include <linux/uaccess.h>
22
23#include "probes-common.h"
24
25/*
26 * Calculate and return exception PC in case of branch delay slot
27 * for microMIPS and MIPS16e. It does not clear the ISA mode bit.
28 */
29int __isa_exception_epc(struct pt_regs *regs)
30{
31 unsigned short inst;
32 long epc = regs->cp0_epc;
33
34 /* Calculate exception PC in branch delay slot. */
35 if (__get_user(inst, (u16 __user *) msk_isa16_mode(epc))) {
36 /* This should never happen because delay slot was checked. */
37 force_sig(SIGSEGV);
38 return epc;
39 }
40 if (cpu_has_mips16) {
41 union mips16e_instruction inst_mips16e;
42
43 inst_mips16e.full = inst;
44 if (inst_mips16e.ri.opcode == MIPS16e_jal_op)
45 epc += 4;
46 else
47 epc += 2;
48 } else if (mm_insn_16bit(inst))
49 epc += 2;
50 else
51 epc += 4;
52
53 return epc;
54}
55
56/* (microMIPS) Convert 16-bit register encoding to 32-bit register encoding. */
57static const unsigned int reg16to32map[8] = {16, 17, 2, 3, 4, 5, 6, 7};
58
59int __mm_isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
60 unsigned long *contpc)
61{
62 union mips_instruction insn = (union mips_instruction)dec_insn.insn;
63 int __maybe_unused bc_false = 0;
64
65 if (!cpu_has_mmips)
66 return 0;
67
68 switch (insn.mm_i_format.opcode) {
69 case mm_pool32a_op:
70 if ((insn.mm_i_format.simmediate & MM_POOL32A_MINOR_MASK) ==
71 mm_pool32axf_op) {
72 switch (insn.mm_i_format.simmediate >>
73 MM_POOL32A_MINOR_SHIFT) {
74 case mm_jalr_op:
75 case mm_jalrhb_op:
76 case mm_jalrs_op:
77 case mm_jalrshb_op:
78 if (insn.mm_i_format.rt != 0) /* Not mm_jr */
79 regs->regs[insn.mm_i_format.rt] =
80 regs->cp0_epc +
81 dec_insn.pc_inc +
82 dec_insn.next_pc_inc;
83 *contpc = regs->regs[insn.mm_i_format.rs];
84 return 1;
85 }
86 }
87 break;
88 case mm_pool32i_op:
89 switch (insn.mm_i_format.rt) {
90 case mm_bltzals_op:
91 case mm_bltzal_op:
92 regs->regs[31] = regs->cp0_epc +
93 dec_insn.pc_inc +
94 dec_insn.next_pc_inc;
95 fallthrough;
96 case mm_bltz_op:
97 if ((long)regs->regs[insn.mm_i_format.rs] < 0)
98 *contpc = regs->cp0_epc +
99 dec_insn.pc_inc +
100 (insn.mm_i_format.simmediate << 1);
101 else
102 *contpc = regs->cp0_epc +
103 dec_insn.pc_inc +
104 dec_insn.next_pc_inc;
105 return 1;
106 case mm_bgezals_op:
107 case mm_bgezal_op:
108 regs->regs[31] = regs->cp0_epc +
109 dec_insn.pc_inc +
110 dec_insn.next_pc_inc;
111 fallthrough;
112 case mm_bgez_op:
113 if ((long)regs->regs[insn.mm_i_format.rs] >= 0)
114 *contpc = regs->cp0_epc +
115 dec_insn.pc_inc +
116 (insn.mm_i_format.simmediate << 1);
117 else
118 *contpc = regs->cp0_epc +
119 dec_insn.pc_inc +
120 dec_insn.next_pc_inc;
121 return 1;
122 case mm_blez_op:
123 if ((long)regs->regs[insn.mm_i_format.rs] <= 0)
124 *contpc = regs->cp0_epc +
125 dec_insn.pc_inc +
126 (insn.mm_i_format.simmediate << 1);
127 else
128 *contpc = regs->cp0_epc +
129 dec_insn.pc_inc +
130 dec_insn.next_pc_inc;
131 return 1;
132 case mm_bgtz_op:
133 if ((long)regs->regs[insn.mm_i_format.rs] <= 0)
134 *contpc = regs->cp0_epc +
135 dec_insn.pc_inc +
136 (insn.mm_i_format.simmediate << 1);
137 else
138 *contpc = regs->cp0_epc +
139 dec_insn.pc_inc +
140 dec_insn.next_pc_inc;
141 return 1;
142#ifdef CONFIG_MIPS_FP_SUPPORT
143 case mm_bc2f_op:
144 case mm_bc1f_op: {
145 unsigned int fcr31;
146 unsigned int bit;
147
148 bc_false = 1;
149 fallthrough;
150 case mm_bc2t_op:
151 case mm_bc1t_op:
152 preempt_disable();
153 if (is_fpu_owner())
154 fcr31 = read_32bit_cp1_register(CP1_STATUS);
155 else
156 fcr31 = current->thread.fpu.fcr31;
157 preempt_enable();
158
159 if (bc_false)
160 fcr31 = ~fcr31;
161
162 bit = (insn.mm_i_format.rs >> 2);
163 bit += (bit != 0);
164 bit += 23;
165 if (fcr31 & (1 << bit))
166 *contpc = regs->cp0_epc +
167 dec_insn.pc_inc +
168 (insn.mm_i_format.simmediate << 1);
169 else
170 *contpc = regs->cp0_epc +
171 dec_insn.pc_inc + dec_insn.next_pc_inc;
172 return 1;
173 }
174#endif /* CONFIG_MIPS_FP_SUPPORT */
175 }
176 break;
177 case mm_pool16c_op:
178 switch (insn.mm_i_format.rt) {
179 case mm_jalr16_op:
180 case mm_jalrs16_op:
181 regs->regs[31] = regs->cp0_epc +
182 dec_insn.pc_inc + dec_insn.next_pc_inc;
183 fallthrough;
184 case mm_jr16_op:
185 *contpc = regs->regs[insn.mm_i_format.rs];
186 return 1;
187 }
188 break;
189 case mm_beqz16_op:
190 if ((long)regs->regs[reg16to32map[insn.mm_b1_format.rs]] == 0)
191 *contpc = regs->cp0_epc +
192 dec_insn.pc_inc +
193 (insn.mm_b1_format.simmediate << 1);
194 else
195 *contpc = regs->cp0_epc +
196 dec_insn.pc_inc + dec_insn.next_pc_inc;
197 return 1;
198 case mm_bnez16_op:
199 if ((long)regs->regs[reg16to32map[insn.mm_b1_format.rs]] != 0)
200 *contpc = regs->cp0_epc +
201 dec_insn.pc_inc +
202 (insn.mm_b1_format.simmediate << 1);
203 else
204 *contpc = regs->cp0_epc +
205 dec_insn.pc_inc + dec_insn.next_pc_inc;
206 return 1;
207 case mm_b16_op:
208 *contpc = regs->cp0_epc + dec_insn.pc_inc +
209 (insn.mm_b0_format.simmediate << 1);
210 return 1;
211 case mm_beq32_op:
212 if (regs->regs[insn.mm_i_format.rs] ==
213 regs->regs[insn.mm_i_format.rt])
214 *contpc = regs->cp0_epc +
215 dec_insn.pc_inc +
216 (insn.mm_i_format.simmediate << 1);
217 else
218 *contpc = regs->cp0_epc +
219 dec_insn.pc_inc +
220 dec_insn.next_pc_inc;
221 return 1;
222 case mm_bne32_op:
223 if (regs->regs[insn.mm_i_format.rs] !=
224 regs->regs[insn.mm_i_format.rt])
225 *contpc = regs->cp0_epc +
226 dec_insn.pc_inc +
227 (insn.mm_i_format.simmediate << 1);
228 else
229 *contpc = regs->cp0_epc +
230 dec_insn.pc_inc + dec_insn.next_pc_inc;
231 return 1;
232 case mm_jalx32_op:
233 regs->regs[31] = regs->cp0_epc +
234 dec_insn.pc_inc + dec_insn.next_pc_inc;
235 *contpc = regs->cp0_epc + dec_insn.pc_inc;
236 *contpc >>= 28;
237 *contpc <<= 28;
238 *contpc |= (insn.j_format.target << 2);
239 return 1;
240 case mm_jals32_op:
241 case mm_jal32_op:
242 regs->regs[31] = regs->cp0_epc +
243 dec_insn.pc_inc + dec_insn.next_pc_inc;
244 fallthrough;
245 case mm_j32_op:
246 *contpc = regs->cp0_epc + dec_insn.pc_inc;
247 *contpc >>= 27;
248 *contpc <<= 27;
249 *contpc |= (insn.j_format.target << 1);
250 set_isa16_mode(*contpc);
251 return 1;
252 }
253 return 0;
254}
255
256/*
257 * Compute return address and emulate branch in microMIPS mode after an
258 * exception only. It does not handle compact branches/jumps and cannot
259 * be used in interrupt context. (Compact branches/jumps do not cause
260 * exceptions.)
261 */
262int __microMIPS_compute_return_epc(struct pt_regs *regs)
263{
264 u16 __user *pc16;
265 u16 halfword;
266 unsigned int word;
267 unsigned long contpc;
268 struct mm_decoded_insn mminsn = { 0 };
269
270 mminsn.micro_mips_mode = 1;
271
272 /* This load never faults. */
273 pc16 = (unsigned short __user *)msk_isa16_mode(regs->cp0_epc);
274 __get_user(halfword, pc16);
275 pc16++;
276 contpc = regs->cp0_epc + 2;
277 word = ((unsigned int)halfword << 16);
278 mminsn.pc_inc = 2;
279
280 if (!mm_insn_16bit(halfword)) {
281 __get_user(halfword, pc16);
282 pc16++;
283 contpc = regs->cp0_epc + 4;
284 mminsn.pc_inc = 4;
285 word |= halfword;
286 }
287 mminsn.insn = word;
288
289 if (get_user(halfword, pc16))
290 goto sigsegv;
291 mminsn.next_pc_inc = 2;
292 word = ((unsigned int)halfword << 16);
293
294 if (!mm_insn_16bit(halfword)) {
295 pc16++;
296 if (get_user(halfword, pc16))
297 goto sigsegv;
298 mminsn.next_pc_inc = 4;
299 word |= halfword;
300 }
301 mminsn.next_insn = word;
302
303 mm_isBranchInstr(regs, mminsn, &contpc);
304
305 regs->cp0_epc = contpc;
306
307 return 0;
308
309sigsegv:
310 force_sig(SIGSEGV);
311 return -EFAULT;
312}
313
314/*
315 * Compute return address and emulate branch in MIPS16e mode after an
316 * exception only. It does not handle compact branches/jumps and cannot
317 * be used in interrupt context. (Compact branches/jumps do not cause
318 * exceptions.)
319 */
320int __MIPS16e_compute_return_epc(struct pt_regs *regs)
321{
322 u16 __user *addr;
323 union mips16e_instruction inst;
324 u16 inst2;
325 u32 fullinst;
326 long epc;
327
328 epc = regs->cp0_epc;
329
330 /* Read the instruction. */
331 addr = (u16 __user *)msk_isa16_mode(epc);
332 if (__get_user(inst.full, addr)) {
333 force_sig(SIGSEGV);
334 return -EFAULT;
335 }
336
337 switch (inst.ri.opcode) {
338 case MIPS16e_extend_op:
339 regs->cp0_epc += 4;
340 return 0;
341
342 /*
343 * JAL and JALX in MIPS16e mode
344 */
345 case MIPS16e_jal_op:
346 addr += 1;
347 if (__get_user(inst2, addr)) {
348 force_sig(SIGSEGV);
349 return -EFAULT;
350 }
351 fullinst = ((unsigned)inst.full << 16) | inst2;
352 regs->regs[31] = epc + 6;
353 epc += 4;
354 epc >>= 28;
355 epc <<= 28;
356 /*
357 * JAL:5 X:1 TARGET[20-16]:5 TARGET[25:21]:5 TARGET[15:0]:16
358 *
359 * ......TARGET[15:0].................TARGET[20:16]...........
360 * ......TARGET[25:21]
361 */
362 epc |=
363 ((fullinst & 0xffff) << 2) | ((fullinst & 0x3e00000) >> 3) |
364 ((fullinst & 0x1f0000) << 7);
365 if (!inst.jal.x)
366 set_isa16_mode(epc); /* Set ISA mode bit. */
367 regs->cp0_epc = epc;
368 return 0;
369
370 /*
371 * J(AL)R(C)
372 */
373 case MIPS16e_rr_op:
374 if (inst.rr.func == MIPS16e_jr_func) {
375
376 if (inst.rr.ra)
377 regs->cp0_epc = regs->regs[31];
378 else
379 regs->cp0_epc =
380 regs->regs[reg16to32[inst.rr.rx]];
381
382 if (inst.rr.l) {
383 if (inst.rr.nd)
384 regs->regs[31] = epc + 2;
385 else
386 regs->regs[31] = epc + 4;
387 }
388 return 0;
389 }
390 break;
391 }
392
393 /*
394 * All other cases have no branch delay slot and are 16-bits.
395 * Branches do not cause an exception.
396 */
397 regs->cp0_epc += 2;
398
399 return 0;
400}
401
402/**
403 * __compute_return_epc_for_insn - Computes the return address and do emulate
404 * branch simulation, if required.
405 *
406 * @regs: Pointer to pt_regs
407 * @insn: branch instruction to decode
408 * Return: -EFAULT on error and forces SIGILL, and on success
409 * returns 0 or BRANCH_LIKELY_TAKEN as appropriate after
410 * evaluating the branch.
411 *
412 * MIPS R6 Compact branches and forbidden slots:
413 * Compact branches do not throw exceptions because they do
414 * not have delay slots. The forbidden slot instruction ($PC+4)
415 * is only executed if the branch was not taken. Otherwise the
416 * forbidden slot is skipped entirely. This means that the
417 * only possible reason to be here because of a MIPS R6 compact
418 * branch instruction is that the forbidden slot has thrown one.
419 * In that case the branch was not taken, so the EPC can be safely
420 * set to EPC + 8.
421 */
422int __compute_return_epc_for_insn(struct pt_regs *regs,
423 union mips_instruction insn)
424{
425 long epc = regs->cp0_epc;
426 unsigned int dspcontrol;
427 int ret = 0;
428
429 switch (insn.i_format.opcode) {
430 /*
431 * jr and jalr are in r_format format.
432 */
433 case spec_op:
434 switch (insn.r_format.func) {
435 case jalr_op:
436 regs->regs[insn.r_format.rd] = epc + 8;
437 fallthrough;
438 case jr_op:
439 if (NO_R6EMU && insn.r_format.func == jr_op)
440 goto sigill_r2r6;
441 regs->cp0_epc = regs->regs[insn.r_format.rs];
442 break;
443 }
444 break;
445
446 /*
447 * This group contains:
448 * bltz_op, bgez_op, bltzl_op, bgezl_op,
449 * bltzal_op, bgezal_op, bltzall_op, bgezall_op.
450 */
451 case bcond_op:
452 switch (insn.i_format.rt) {
453 case bltzl_op:
454 if (NO_R6EMU)
455 goto sigill_r2r6;
456 fallthrough;
457 case bltz_op:
458 if ((long)regs->regs[insn.i_format.rs] < 0) {
459 epc = epc + 4 + (insn.i_format.simmediate << 2);
460 if (insn.i_format.rt == bltzl_op)
461 ret = BRANCH_LIKELY_TAKEN;
462 } else
463 epc += 8;
464 regs->cp0_epc = epc;
465 break;
466
467 case bgezl_op:
468 if (NO_R6EMU)
469 goto sigill_r2r6;
470 fallthrough;
471 case bgez_op:
472 if ((long)regs->regs[insn.i_format.rs] >= 0) {
473 epc = epc + 4 + (insn.i_format.simmediate << 2);
474 if (insn.i_format.rt == bgezl_op)
475 ret = BRANCH_LIKELY_TAKEN;
476 } else
477 epc += 8;
478 regs->cp0_epc = epc;
479 break;
480
481 case bltzal_op:
482 case bltzall_op:
483 if (NO_R6EMU && (insn.i_format.rs ||
484 insn.i_format.rt == bltzall_op))
485 goto sigill_r2r6;
486 regs->regs[31] = epc + 8;
487 /*
488 * OK we are here either because we hit a NAL
489 * instruction or because we are emulating an
490 * old bltzal{,l} one. Let's figure out what the
491 * case really is.
492 */
493 if (!insn.i_format.rs) {
494 /*
495 * NAL or BLTZAL with rs == 0
496 * Doesn't matter if we are R6 or not. The
497 * result is the same
498 */
499 regs->cp0_epc += 4 +
500 (insn.i_format.simmediate << 2);
501 break;
502 }
503 /* Now do the real thing for non-R6 BLTZAL{,L} */
504 if ((long)regs->regs[insn.i_format.rs] < 0) {
505 epc = epc + 4 + (insn.i_format.simmediate << 2);
506 if (insn.i_format.rt == bltzall_op)
507 ret = BRANCH_LIKELY_TAKEN;
508 } else
509 epc += 8;
510 regs->cp0_epc = epc;
511 break;
512
513 case bgezal_op:
514 case bgezall_op:
515 if (NO_R6EMU && (insn.i_format.rs ||
516 insn.i_format.rt == bgezall_op))
517 goto sigill_r2r6;
518 regs->regs[31] = epc + 8;
519 /*
520 * OK we are here either because we hit a BAL
521 * instruction or because we are emulating an
522 * old bgezal{,l} one. Let's figure out what the
523 * case really is.
524 */
525 if (!insn.i_format.rs) {
526 /*
527 * BAL or BGEZAL with rs == 0
528 * Doesn't matter if we are R6 or not. The
529 * result is the same
530 */
531 regs->cp0_epc += 4 +
532 (insn.i_format.simmediate << 2);
533 break;
534 }
535 /* Now do the real thing for non-R6 BGEZAL{,L} */
536 if ((long)regs->regs[insn.i_format.rs] >= 0) {
537 epc = epc + 4 + (insn.i_format.simmediate << 2);
538 if (insn.i_format.rt == bgezall_op)
539 ret = BRANCH_LIKELY_TAKEN;
540 } else
541 epc += 8;
542 regs->cp0_epc = epc;
543 break;
544
545 case bposge32_op:
546 if (!cpu_has_dsp)
547 goto sigill_dsp;
548
549 dspcontrol = rddsp(0x01);
550
551 if (dspcontrol >= 32) {
552 epc = epc + 4 + (insn.i_format.simmediate << 2);
553 } else
554 epc += 8;
555 regs->cp0_epc = epc;
556 break;
557 }
558 break;
559
560 /*
561 * These are unconditional and in j_format.
562 */
563 case jalx_op:
564 case jal_op:
565 regs->regs[31] = regs->cp0_epc + 8;
566 fallthrough;
567 case j_op:
568 epc += 4;
569 epc >>= 28;
570 epc <<= 28;
571 epc |= (insn.j_format.target << 2);
572 regs->cp0_epc = epc;
573 if (insn.i_format.opcode == jalx_op)
574 set_isa16_mode(regs->cp0_epc);
575 break;
576
577 /*
578 * These are conditional and in i_format.
579 */
580 case beql_op:
581 if (NO_R6EMU)
582 goto sigill_r2r6;
583 fallthrough;
584 case beq_op:
585 if (regs->regs[insn.i_format.rs] ==
586 regs->regs[insn.i_format.rt]) {
587 epc = epc + 4 + (insn.i_format.simmediate << 2);
588 if (insn.i_format.opcode == beql_op)
589 ret = BRANCH_LIKELY_TAKEN;
590 } else
591 epc += 8;
592 regs->cp0_epc = epc;
593 break;
594
595 case bnel_op:
596 if (NO_R6EMU)
597 goto sigill_r2r6;
598 fallthrough;
599 case bne_op:
600 if (regs->regs[insn.i_format.rs] !=
601 regs->regs[insn.i_format.rt]) {
602 epc = epc + 4 + (insn.i_format.simmediate << 2);
603 if (insn.i_format.opcode == bnel_op)
604 ret = BRANCH_LIKELY_TAKEN;
605 } else
606 epc += 8;
607 regs->cp0_epc = epc;
608 break;
609
610 case blezl_op: /* not really i_format */
611 if (!insn.i_format.rt && NO_R6EMU)
612 goto sigill_r2r6;
613 fallthrough;
614 case blez_op:
615 /*
616 * Compact branches for R6 for the
617 * blez and blezl opcodes.
618 * BLEZ | rs = 0 | rt != 0 == BLEZALC
619 * BLEZ | rs = rt != 0 == BGEZALC
620 * BLEZ | rs != 0 | rt != 0 == BGEUC
621 * BLEZL | rs = 0 | rt != 0 == BLEZC
622 * BLEZL | rs = rt != 0 == BGEZC
623 * BLEZL | rs != 0 | rt != 0 == BGEC
624 *
625 * For real BLEZ{,L}, rt is always 0.
626 */
627
628 if (cpu_has_mips_r6 && insn.i_format.rt) {
629 if ((insn.i_format.opcode == blez_op) &&
630 ((!insn.i_format.rs && insn.i_format.rt) ||
631 (insn.i_format.rs == insn.i_format.rt)))
632 regs->regs[31] = epc + 4;
633 regs->cp0_epc += 8;
634 break;
635 }
636 /* rt field assumed to be zero */
637 if ((long)regs->regs[insn.i_format.rs] <= 0) {
638 epc = epc + 4 + (insn.i_format.simmediate << 2);
639 if (insn.i_format.opcode == blezl_op)
640 ret = BRANCH_LIKELY_TAKEN;
641 } else
642 epc += 8;
643 regs->cp0_epc = epc;
644 break;
645
646 case bgtzl_op:
647 if (!insn.i_format.rt && NO_R6EMU)
648 goto sigill_r2r6;
649 fallthrough;
650 case bgtz_op:
651 /*
652 * Compact branches for R6 for the
653 * bgtz and bgtzl opcodes.
654 * BGTZ | rs = 0 | rt != 0 == BGTZALC
655 * BGTZ | rs = rt != 0 == BLTZALC
656 * BGTZ | rs != 0 | rt != 0 == BLTUC
657 * BGTZL | rs = 0 | rt != 0 == BGTZC
658 * BGTZL | rs = rt != 0 == BLTZC
659 * BGTZL | rs != 0 | rt != 0 == BLTC
660 *
661 * *ZALC varint for BGTZ &&& rt != 0
662 * For real GTZ{,L}, rt is always 0.
663 */
664 if (cpu_has_mips_r6 && insn.i_format.rt) {
665 if ((insn.i_format.opcode == blez_op) &&
666 ((!insn.i_format.rs && insn.i_format.rt) ||
667 (insn.i_format.rs == insn.i_format.rt)))
668 regs->regs[31] = epc + 4;
669 regs->cp0_epc += 8;
670 break;
671 }
672
673 /* rt field assumed to be zero */
674 if ((long)regs->regs[insn.i_format.rs] > 0) {
675 epc = epc + 4 + (insn.i_format.simmediate << 2);
676 if (insn.i_format.opcode == bgtzl_op)
677 ret = BRANCH_LIKELY_TAKEN;
678 } else
679 epc += 8;
680 regs->cp0_epc = epc;
681 break;
682
683#ifdef CONFIG_MIPS_FP_SUPPORT
684 /*
685 * And now the FPA/cp1 branch instructions.
686 */
687 case cop1_op: {
688 unsigned int bit, fcr31, reg;
689
690 if (cpu_has_mips_r6 &&
691 ((insn.i_format.rs == bc1eqz_op) ||
692 (insn.i_format.rs == bc1nez_op))) {
693 if (!init_fp_ctx(current))
694 lose_fpu(1);
695 reg = insn.i_format.rt;
696 bit = get_fpr32(&current->thread.fpu.fpr[reg], 0) & 0x1;
697 if (insn.i_format.rs == bc1eqz_op)
698 bit = !bit;
699 own_fpu(1);
700 if (bit)
701 epc = epc + 4 +
702 (insn.i_format.simmediate << 2);
703 else
704 epc += 8;
705 regs->cp0_epc = epc;
706
707 break;
708 } else {
709
710 preempt_disable();
711 if (is_fpu_owner())
712 fcr31 = read_32bit_cp1_register(CP1_STATUS);
713 else
714 fcr31 = current->thread.fpu.fcr31;
715 preempt_enable();
716
717 bit = (insn.i_format.rt >> 2);
718 bit += (bit != 0);
719 bit += 23;
720 switch (insn.i_format.rt & 3) {
721 case 0: /* bc1f */
722 case 2: /* bc1fl */
723 if (~fcr31 & (1 << bit)) {
724 epc = epc + 4 +
725 (insn.i_format.simmediate << 2);
726 if (insn.i_format.rt == 2)
727 ret = BRANCH_LIKELY_TAKEN;
728 } else
729 epc += 8;
730 regs->cp0_epc = epc;
731 break;
732
733 case 1: /* bc1t */
734 case 3: /* bc1tl */
735 if (fcr31 & (1 << bit)) {
736 epc = epc + 4 +
737 (insn.i_format.simmediate << 2);
738 if (insn.i_format.rt == 3)
739 ret = BRANCH_LIKELY_TAKEN;
740 } else
741 epc += 8;
742 regs->cp0_epc = epc;
743 break;
744 }
745 break;
746 }
747 }
748#endif /* CONFIG_MIPS_FP_SUPPORT */
749
750#ifdef CONFIG_CPU_CAVIUM_OCTEON
751 case lwc2_op: /* This is bbit0 on Octeon */
752 if ((regs->regs[insn.i_format.rs] & (1ull<<insn.i_format.rt))
753 == 0)
754 epc = epc + 4 + (insn.i_format.simmediate << 2);
755 else
756 epc += 8;
757 regs->cp0_epc = epc;
758 break;
759 case ldc2_op: /* This is bbit032 on Octeon */
760 if ((regs->regs[insn.i_format.rs] &
761 (1ull<<(insn.i_format.rt+32))) == 0)
762 epc = epc + 4 + (insn.i_format.simmediate << 2);
763 else
764 epc += 8;
765 regs->cp0_epc = epc;
766 break;
767 case swc2_op: /* This is bbit1 on Octeon */
768 if (regs->regs[insn.i_format.rs] & (1ull<<insn.i_format.rt))
769 epc = epc + 4 + (insn.i_format.simmediate << 2);
770 else
771 epc += 8;
772 regs->cp0_epc = epc;
773 break;
774 case sdc2_op: /* This is bbit132 on Octeon */
775 if (regs->regs[insn.i_format.rs] &
776 (1ull<<(insn.i_format.rt+32)))
777 epc = epc + 4 + (insn.i_format.simmediate << 2);
778 else
779 epc += 8;
780 regs->cp0_epc = epc;
781 break;
782#else
783 case bc6_op:
784 /* Only valid for MIPS R6 */
785 if (!cpu_has_mips_r6)
786 goto sigill_r6;
787 regs->cp0_epc += 8;
788 break;
789 case balc6_op:
790 if (!cpu_has_mips_r6)
791 goto sigill_r6;
792 /* Compact branch: BALC */
793 regs->regs[31] = epc + 4;
794 epc += 4 + (insn.i_format.simmediate << 2);
795 regs->cp0_epc = epc;
796 break;
797 case pop66_op:
798 if (!cpu_has_mips_r6)
799 goto sigill_r6;
800 /* Compact branch: BEQZC || JIC */
801 regs->cp0_epc += 8;
802 break;
803 case pop76_op:
804 if (!cpu_has_mips_r6)
805 goto sigill_r6;
806 /* Compact branch: BNEZC || JIALC */
807 if (!insn.i_format.rs) {
808 /* JIALC: set $31/ra */
809 regs->regs[31] = epc + 4;
810 }
811 regs->cp0_epc += 8;
812 break;
813#endif
814 case pop10_op:
815 case pop30_op:
816 /* Only valid for MIPS R6 */
817 if (!cpu_has_mips_r6)
818 goto sigill_r6;
819 /*
820 * Compact branches:
821 * bovc, beqc, beqzalc, bnvc, bnec, bnezlac
822 */
823 if (insn.i_format.rt && !insn.i_format.rs)
824 regs->regs[31] = epc + 4;
825 regs->cp0_epc += 8;
826 break;
827 }
828
829 return ret;
830
831sigill_dsp:
832 pr_debug("%s: DSP branch but not DSP ASE - sending SIGILL.\n",
833 current->comm);
834 force_sig(SIGILL);
835 return -EFAULT;
836sigill_r2r6:
837 pr_debug("%s: R2 branch but r2-to-r6 emulator is not present - sending SIGILL.\n",
838 current->comm);
839 force_sig(SIGILL);
840 return -EFAULT;
841sigill_r6:
842 pr_debug("%s: R6 branch but no MIPSr6 ISA support - sending SIGILL.\n",
843 current->comm);
844 force_sig(SIGILL);
845 return -EFAULT;
846}
847EXPORT_SYMBOL_GPL(__compute_return_epc_for_insn);
848
849int __compute_return_epc(struct pt_regs *regs)
850{
851 unsigned int __user *addr;
852 long epc;
853 union mips_instruction insn;
854
855 epc = regs->cp0_epc;
856 if (epc & 3)
857 goto unaligned;
858
859 /*
860 * Read the instruction
861 */
862 addr = (unsigned int __user *) epc;
863 if (__get_user(insn.word, addr)) {
864 force_sig(SIGSEGV);
865 return -EFAULT;
866 }
867
868 return __compute_return_epc_for_insn(regs, insn);
869
870unaligned:
871 printk("%s: unaligned epc - sending SIGBUS.\n", current->comm);
872 force_sig(SIGBUS);
873 return -EFAULT;
874}
875
876#if (defined CONFIG_KPROBES) || (defined CONFIG_UPROBES)
877
878int __insn_is_compact_branch(union mips_instruction insn)
879{
880 if (!cpu_has_mips_r6)
881 return 0;
882
883 switch (insn.i_format.opcode) {
884 case blezl_op:
885 case bgtzl_op:
886 case blez_op:
887 case bgtz_op:
888 /*
889 * blez[l] and bgtz[l] opcodes with non-zero rt
890 * are MIPS R6 compact branches
891 */
892 if (insn.i_format.rt)
893 return 1;
894 break;
895 case bc6_op:
896 case balc6_op:
897 case pop10_op:
898 case pop30_op:
899 case pop66_op:
900 case pop76_op:
901 return 1;
902 }
903
904 return 0;
905}
906EXPORT_SYMBOL_GPL(__insn_is_compact_branch);
907
908#endif /* CONFIG_KPROBES || CONFIG_UPROBES */