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) 1991, 1992 Linus Torvalds
7 * Copyright (C) 1994 - 2000 Ralf Baechle
8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
9 * Copyright (C) 2014, Imagination Technologies Ltd.
10 */
11 #include <linux/cache.h>
12 #include <linux/context_tracking.h>
13 #include <linux/irqflags.h>
14 #include <linux/sched.h>
15 #include <linux/mm.h>
16 #include <linux/personality.h>
17 #include <linux/smp.h>
18 #include <linux/kernel.h>
19 #include <linux/signal.h>
20 #include <linux/errno.h>
21 #include <linux/wait.h>
22 #include <linux/ptrace.h>
23 #include <linux/unistd.h>
24 #include <linux/uprobes.h>
25 #include <linux/compiler.h>
26 #include <linux/syscalls.h>
27 #include <linux/uaccess.h>
28 #include <linux/resume_user_mode.h>
29
30 #include <asm/abi.h>
31 #include <asm/asm.h>
32 #include <linux/bitops.h>
33 #include <asm/cacheflush.h>
34 #include <asm/fpu.h>
35 #include <asm/sim.h>
36 #include <asm/ucontext.h>
37 #include <asm/cpu-features.h>
38 #include <asm/dsp.h>
39 #include <asm/inst.h>
40 #include <asm/msa.h>
41
42 #include "signal-common.h"
43
44 static int (*save_fp_context)(void __user *sc);
45 static int (*restore_fp_context)(void __user *sc);
46
47 struct sigframe {
48 u32 sf_ass[4]; /* argument save space for o32 */
49 u32 sf_pad[2]; /* Was: signal trampoline */
50
51 /* Matches struct ucontext from its uc_mcontext field onwards */
52 struct sigcontext sf_sc;
53 sigset_t sf_mask;
54 unsigned long long sf_extcontext[];
55 };
56
57 struct rt_sigframe {
58 u32 rs_ass[4]; /* argument save space for o32 */
59 u32 rs_pad[2]; /* Was: signal trampoline */
60 struct siginfo rs_info;
61 struct ucontext rs_uc;
62 };
63
64 #ifdef CONFIG_MIPS_FP_SUPPORT
65
66 /*
67 * Thread saved context copy to/from a signal context presumed to be on the
68 * user stack, and therefore accessed with appropriate macros from uaccess.h.
69 */
copy_fp_to_sigcontext(void __user * sc)70 static int copy_fp_to_sigcontext(void __user *sc)
71 {
72 struct mips_abi *abi = current->thread.abi;
73 uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
74 uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
75 int i;
76 int err = 0;
77 int inc = test_thread_flag(TIF_32BIT_FPREGS) ? 2 : 1;
78
79 for (i = 0; i < NUM_FPU_REGS; i += inc) {
80 err |=
81 __put_user(get_fpr64(¤t->thread.fpu.fpr[i], 0),
82 &fpregs[i]);
83 }
84 err |= __put_user(current->thread.fpu.fcr31, csr);
85
86 return err;
87 }
88
copy_fp_from_sigcontext(void __user * sc)89 static int copy_fp_from_sigcontext(void __user *sc)
90 {
91 struct mips_abi *abi = current->thread.abi;
92 uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
93 uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
94 int i;
95 int err = 0;
96 int inc = test_thread_flag(TIF_32BIT_FPREGS) ? 2 : 1;
97 u64 fpr_val;
98
99 for (i = 0; i < NUM_FPU_REGS; i += inc) {
100 err |= __get_user(fpr_val, &fpregs[i]);
101 set_fpr64(¤t->thread.fpu.fpr[i], 0, fpr_val);
102 }
103 err |= __get_user(current->thread.fpu.fcr31, csr);
104
105 return err;
106 }
107
108 #else /* !CONFIG_MIPS_FP_SUPPORT */
109
copy_fp_to_sigcontext(void __user * sc)110 static int copy_fp_to_sigcontext(void __user *sc)
111 {
112 return 0;
113 }
114
copy_fp_from_sigcontext(void __user * sc)115 static int copy_fp_from_sigcontext(void __user *sc)
116 {
117 return 0;
118 }
119
120 #endif /* !CONFIG_MIPS_FP_SUPPORT */
121
122 /*
123 * Wrappers for the assembly _{save,restore}_fp_context functions.
124 */
save_hw_fp_context(void __user * sc)125 static int save_hw_fp_context(void __user *sc)
126 {
127 struct mips_abi *abi = current->thread.abi;
128 uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
129 uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
130
131 return _save_fp_context(fpregs, csr);
132 }
133
restore_hw_fp_context(void __user * sc)134 static int restore_hw_fp_context(void __user *sc)
135 {
136 struct mips_abi *abi = current->thread.abi;
137 uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
138 uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
139
140 return _restore_fp_context(fpregs, csr);
141 }
142
143 /*
144 * Extended context handling.
145 */
146
sc_to_extcontext(void __user * sc)147 static inline void __user *sc_to_extcontext(void __user *sc)
148 {
149 struct ucontext __user *uc;
150
151 /*
152 * We can just pretend the sigcontext is always embedded in a struct
153 * ucontext here, because the offset from sigcontext to extended
154 * context is the same in the struct sigframe case.
155 */
156 uc = container_of(sc, struct ucontext, uc_mcontext);
157 return &uc->uc_extcontext;
158 }
159
160 #ifdef CONFIG_CPU_HAS_MSA
161
save_msa_extcontext(void __user * buf)162 static int save_msa_extcontext(void __user *buf)
163 {
164 struct msa_extcontext __user *msa = buf;
165 uint64_t val;
166 int i, err;
167
168 if (!thread_msa_context_live())
169 return 0;
170
171 /*
172 * Ensure that we can't lose the live MSA context between checking
173 * for it & writing it to memory.
174 */
175 preempt_disable();
176
177 if (is_msa_enabled()) {
178 /*
179 * There are no EVA versions of the vector register load/store
180 * instructions, so MSA context has to be saved to kernel memory
181 * and then copied to user memory. The save to kernel memory
182 * should already have been done when handling scalar FP
183 * context.
184 */
185 BUG_ON(IS_ENABLED(CONFIG_EVA));
186
187 err = __put_user(read_msa_csr(), &msa->csr);
188 err |= _save_msa_all_upper(&msa->wr);
189
190 preempt_enable();
191 } else {
192 preempt_enable();
193
194 err = __put_user(current->thread.fpu.msacsr, &msa->csr);
195
196 for (i = 0; i < NUM_FPU_REGS; i++) {
197 val = get_fpr64(¤t->thread.fpu.fpr[i], 1);
198 err |= __put_user(val, &msa->wr[i]);
199 }
200 }
201
202 err |= __put_user(MSA_EXTCONTEXT_MAGIC, &msa->ext.magic);
203 err |= __put_user(sizeof(*msa), &msa->ext.size);
204
205 return err ? -EFAULT : sizeof(*msa);
206 }
207
restore_msa_extcontext(void __user * buf,unsigned int size)208 static int restore_msa_extcontext(void __user *buf, unsigned int size)
209 {
210 struct msa_extcontext __user *msa = buf;
211 unsigned long long val;
212 unsigned int csr;
213 int i, err;
214
215 if (size != sizeof(*msa))
216 return -EINVAL;
217
218 err = get_user(csr, &msa->csr);
219 if (err)
220 return err;
221
222 preempt_disable();
223
224 if (is_msa_enabled()) {
225 /*
226 * There are no EVA versions of the vector register load/store
227 * instructions, so MSA context has to be copied to kernel
228 * memory and later loaded to registers. The same is true of
229 * scalar FP context, so FPU & MSA should have already been
230 * disabled whilst handling scalar FP context.
231 */
232 BUG_ON(IS_ENABLED(CONFIG_EVA));
233
234 write_msa_csr(csr);
235 err |= _restore_msa_all_upper(&msa->wr);
236 preempt_enable();
237 } else {
238 preempt_enable();
239
240 current->thread.fpu.msacsr = csr;
241
242 for (i = 0; i < NUM_FPU_REGS; i++) {
243 err |= __get_user(val, &msa->wr[i]);
244 set_fpr64(¤t->thread.fpu.fpr[i], 1, val);
245 }
246 }
247
248 return err;
249 }
250
251 #else /* !CONFIG_CPU_HAS_MSA */
252
save_msa_extcontext(void __user * buf)253 static int save_msa_extcontext(void __user *buf)
254 {
255 return 0;
256 }
257
restore_msa_extcontext(void __user * buf,unsigned int size)258 static int restore_msa_extcontext(void __user *buf, unsigned int size)
259 {
260 return SIGSYS;
261 }
262
263 #endif /* !CONFIG_CPU_HAS_MSA */
264
save_extcontext(void __user * buf)265 static int save_extcontext(void __user *buf)
266 {
267 int sz;
268
269 sz = save_msa_extcontext(buf);
270 if (sz < 0)
271 return sz;
272 buf += sz;
273
274 /* If no context was saved then trivially return */
275 if (!sz)
276 return 0;
277
278 /* Write the end marker */
279 if (__put_user(END_EXTCONTEXT_MAGIC, (u32 *)buf))
280 return -EFAULT;
281
282 sz += sizeof(((struct extcontext *)NULL)->magic);
283 return sz;
284 }
285
restore_extcontext(void __user * buf)286 static int restore_extcontext(void __user *buf)
287 {
288 struct extcontext ext;
289 int err;
290
291 while (1) {
292 err = __get_user(ext.magic, (unsigned int *)buf);
293 if (err)
294 return err;
295
296 if (ext.magic == END_EXTCONTEXT_MAGIC)
297 return 0;
298
299 err = __get_user(ext.size, (unsigned int *)(buf
300 + offsetof(struct extcontext, size)));
301 if (err)
302 return err;
303
304 switch (ext.magic) {
305 case MSA_EXTCONTEXT_MAGIC:
306 err = restore_msa_extcontext(buf, ext.size);
307 break;
308
309 default:
310 err = -EINVAL;
311 break;
312 }
313
314 if (err)
315 return err;
316
317 buf += ext.size;
318 }
319 }
320
321 /*
322 * Helper routines
323 */
protected_save_fp_context(void __user * sc)324 int protected_save_fp_context(void __user *sc)
325 {
326 struct mips_abi *abi = current->thread.abi;
327 uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
328 uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
329 uint32_t __user *used_math = sc + abi->off_sc_used_math;
330 unsigned int used, ext_sz;
331 int err;
332
333 used = used_math() ? USED_FP : 0;
334 if (!used)
335 goto fp_done;
336
337 if (!test_thread_flag(TIF_32BIT_FPREGS))
338 used |= USED_FR1;
339 if (test_thread_flag(TIF_HYBRID_FPREGS))
340 used |= USED_HYBRID_FPRS;
341
342 /*
343 * EVA does not have userland equivalents of ldc1 or sdc1, so
344 * save to the kernel FP context & copy that to userland below.
345 */
346 if (IS_ENABLED(CONFIG_EVA))
347 lose_fpu(1);
348
349 while (1) {
350 lock_fpu_owner();
351 if (is_fpu_owner()) {
352 err = save_fp_context(sc);
353 unlock_fpu_owner();
354 } else {
355 unlock_fpu_owner();
356 err = copy_fp_to_sigcontext(sc);
357 }
358 if (likely(!err))
359 break;
360 /* touch the sigcontext and try again */
361 err = __put_user(0, &fpregs[0]) |
362 __put_user(0, &fpregs[31]) |
363 __put_user(0, csr);
364 if (err)
365 return err; /* really bad sigcontext */
366 }
367
368 fp_done:
369 ext_sz = err = save_extcontext(sc_to_extcontext(sc));
370 if (err < 0)
371 return err;
372 used |= ext_sz ? USED_EXTCONTEXT : 0;
373
374 return __put_user(used, used_math);
375 }
376
protected_restore_fp_context(void __user * sc)377 int protected_restore_fp_context(void __user *sc)
378 {
379 struct mips_abi *abi = current->thread.abi;
380 uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
381 uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
382 uint32_t __user *used_math = sc + abi->off_sc_used_math;
383 unsigned int used;
384 int err, sig = 0, tmp __maybe_unused;
385
386 err = __get_user(used, used_math);
387 conditional_used_math(used & USED_FP);
388
389 /*
390 * The signal handler may have used FPU; give it up if the program
391 * doesn't want it following sigreturn.
392 */
393 if (err || !(used & USED_FP))
394 lose_fpu(0);
395 if (err)
396 return err;
397 if (!(used & USED_FP))
398 goto fp_done;
399
400 err = sig = fpcsr_pending(csr);
401 if (err < 0)
402 return err;
403
404 /*
405 * EVA does not have userland equivalents of ldc1 or sdc1, so we
406 * disable the FPU here such that the code below simply copies to
407 * the kernel FP context.
408 */
409 if (IS_ENABLED(CONFIG_EVA))
410 lose_fpu(0);
411
412 while (1) {
413 lock_fpu_owner();
414 if (is_fpu_owner()) {
415 err = restore_fp_context(sc);
416 unlock_fpu_owner();
417 } else {
418 unlock_fpu_owner();
419 err = copy_fp_from_sigcontext(sc);
420 }
421 if (likely(!err))
422 break;
423 /* touch the sigcontext and try again */
424 err = __get_user(tmp, &fpregs[0]) |
425 __get_user(tmp, &fpregs[31]) |
426 __get_user(tmp, csr);
427 if (err)
428 break; /* really bad sigcontext */
429 }
430
431 fp_done:
432 if (!err && (used & USED_EXTCONTEXT))
433 err = restore_extcontext(sc_to_extcontext(sc));
434
435 return err ?: sig;
436 }
437
setup_sigcontext(struct pt_regs * regs,struct sigcontext __user * sc)438 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
439 {
440 int err = 0;
441 int i;
442
443 err |= __put_user(regs->cp0_epc, &sc->sc_pc);
444
445 err |= __put_user(0, &sc->sc_regs[0]);
446 for (i = 1; i < 32; i++)
447 err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
448
449 #ifdef CONFIG_CPU_HAS_SMARTMIPS
450 err |= __put_user(regs->acx, &sc->sc_acx);
451 #endif
452 err |= __put_user(regs->hi, &sc->sc_mdhi);
453 err |= __put_user(regs->lo, &sc->sc_mdlo);
454 if (cpu_has_dsp) {
455 err |= __put_user(mfhi1(), &sc->sc_hi1);
456 err |= __put_user(mflo1(), &sc->sc_lo1);
457 err |= __put_user(mfhi2(), &sc->sc_hi2);
458 err |= __put_user(mflo2(), &sc->sc_lo2);
459 err |= __put_user(mfhi3(), &sc->sc_hi3);
460 err |= __put_user(mflo3(), &sc->sc_lo3);
461 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
462 }
463
464
465 /*
466 * Save FPU state to signal context. Signal handler
467 * will "inherit" current FPU state.
468 */
469 err |= protected_save_fp_context(sc);
470
471 return err;
472 }
473
extcontext_max_size(void)474 static size_t extcontext_max_size(void)
475 {
476 size_t sz = 0;
477
478 /*
479 * The assumption here is that between this point & the point at which
480 * the extended context is saved the size of the context should only
481 * ever be able to shrink (if the task is preempted), but never grow.
482 * That is, what this function returns is an upper bound on the size of
483 * the extended context for the current task at the current time.
484 */
485
486 if (thread_msa_context_live())
487 sz += sizeof(struct msa_extcontext);
488
489 /* If any context is saved then we'll append the end marker */
490 if (sz)
491 sz += sizeof(((struct extcontext *)NULL)->magic);
492
493 return sz;
494 }
495
fpcsr_pending(unsigned int __user * fpcsr)496 int fpcsr_pending(unsigned int __user *fpcsr)
497 {
498 int err, sig = 0;
499 unsigned int csr, enabled;
500
501 err = __get_user(csr, fpcsr);
502 enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
503 /*
504 * If the signal handler set some FPU exceptions, clear it and
505 * send SIGFPE.
506 */
507 if (csr & enabled) {
508 csr &= ~enabled;
509 err |= __put_user(csr, fpcsr);
510 sig = SIGFPE;
511 }
512 return err ?: sig;
513 }
514
restore_sigcontext(struct pt_regs * regs,struct sigcontext __user * sc)515 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
516 {
517 unsigned long treg;
518 int err = 0;
519 int i;
520
521 /* Always make any pending restarted system calls return -EINTR */
522 current->restart_block.fn = do_no_restart_syscall;
523
524 err |= __get_user(regs->cp0_epc, &sc->sc_pc);
525
526 #ifdef CONFIG_CPU_HAS_SMARTMIPS
527 err |= __get_user(regs->acx, &sc->sc_acx);
528 #endif
529 err |= __get_user(regs->hi, &sc->sc_mdhi);
530 err |= __get_user(regs->lo, &sc->sc_mdlo);
531 if (cpu_has_dsp) {
532 err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
533 err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
534 err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
535 err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
536 err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
537 err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
538 err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
539 }
540
541 for (i = 1; i < 32; i++)
542 err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
543
544 return err ?: protected_restore_fp_context(sc);
545 }
546
547 #ifdef CONFIG_WAR_ICACHE_REFILLS
548 #define SIGMASK ~(cpu_icache_line_size()-1)
549 #else
550 #define SIGMASK ALMASK
551 #endif
552
get_sigframe(struct ksignal * ksig,struct pt_regs * regs,size_t frame_size)553 void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
554 size_t frame_size)
555 {
556 unsigned long sp;
557
558 /* Leave space for potential extended context */
559 frame_size += extcontext_max_size();
560
561 /* Default to using normal stack */
562 sp = regs->regs[29];
563
564 /*
565 * If we are on the alternate signal stack and would overflow it, don't.
566 * Return an always-bogus address instead so we will die with SIGSEGV.
567 */
568 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
569 return (void __user __force *)(-1UL);
570
571 /*
572 * FPU emulator may have it's own trampoline active just
573 * above the user stack, 16-bytes before the next lowest
574 * 16 byte boundary. Try to avoid trashing it.
575 */
576 sp -= 32;
577
578 sp = sigsp(sp, ksig);
579
580 return (void __user *)((sp - frame_size) & SIGMASK);
581 }
582
583 /*
584 * Atomically swap in the new signal mask, and wait for a signal.
585 */
586
587 #ifdef CONFIG_TRAD_SIGNALS
SYSCALL_DEFINE1(sigsuspend,sigset_t __user *,uset)588 SYSCALL_DEFINE1(sigsuspend, sigset_t __user *, uset)
589 {
590 return sys_rt_sigsuspend(uset, sizeof(sigset_t));
591 }
592 #endif
593
594 #ifdef CONFIG_TRAD_SIGNALS
SYSCALL_DEFINE3(sigaction,int,sig,const struct sigaction __user *,act,struct sigaction __user *,oact)595 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
596 struct sigaction __user *, oact)
597 {
598 struct k_sigaction new_ka, old_ka;
599 int ret;
600 int err = 0;
601
602 if (act) {
603 old_sigset_t mask;
604
605 if (!access_ok(act, sizeof(*act)))
606 return -EFAULT;
607 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
608 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
609 err |= __get_user(mask, &act->sa_mask.sig[0]);
610 if (err)
611 return -EFAULT;
612
613 siginitset(&new_ka.sa.sa_mask, mask);
614 }
615
616 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
617
618 if (!ret && oact) {
619 if (!access_ok(oact, sizeof(*oact)))
620 return -EFAULT;
621 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
622 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
623 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
624 err |= __put_user(0, &oact->sa_mask.sig[1]);
625 err |= __put_user(0, &oact->sa_mask.sig[2]);
626 err |= __put_user(0, &oact->sa_mask.sig[3]);
627 if (err)
628 return -EFAULT;
629 }
630
631 return ret;
632 }
633 #endif
634
635 #ifdef CONFIG_TRAD_SIGNALS
sys_sigreturn(void)636 asmlinkage void sys_sigreturn(void)
637 {
638 struct sigframe __user *frame;
639 struct pt_regs *regs;
640 sigset_t blocked;
641 int sig;
642
643 regs = current_pt_regs();
644 frame = (struct sigframe __user *)regs->regs[29];
645 if (!access_ok(frame, sizeof(*frame)))
646 goto badframe;
647 if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
648 goto badframe;
649
650 set_current_blocked(&blocked);
651
652 sig = restore_sigcontext(regs, &frame->sf_sc);
653 if (sig < 0)
654 goto badframe;
655 else if (sig)
656 force_sig(sig);
657
658 /*
659 * Don't let your children do this ...
660 */
661 __asm__ __volatile__(
662 "move\t$29, %0\n\t"
663 "j\tsyscall_exit"
664 : /* no outputs */
665 : "r" (regs));
666 /* Unreached */
667
668 badframe:
669 force_sig(SIGSEGV);
670 }
671 #endif /* CONFIG_TRAD_SIGNALS */
672
sys_rt_sigreturn(void)673 asmlinkage void sys_rt_sigreturn(void)
674 {
675 struct rt_sigframe __user *frame;
676 struct pt_regs *regs;
677 sigset_t set;
678 int sig;
679
680 regs = current_pt_regs();
681 frame = (struct rt_sigframe __user *)regs->regs[29];
682 if (!access_ok(frame, sizeof(*frame)))
683 goto badframe;
684 if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
685 goto badframe;
686
687 set_current_blocked(&set);
688
689 sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
690 if (sig < 0)
691 goto badframe;
692 else if (sig)
693 force_sig(sig);
694
695 if (restore_altstack(&frame->rs_uc.uc_stack))
696 goto badframe;
697
698 /*
699 * Don't let your children do this ...
700 */
701 __asm__ __volatile__(
702 "move\t$29, %0\n\t"
703 "j\tsyscall_exit"
704 : /* no outputs */
705 : "r" (regs));
706 /* Unreached */
707
708 badframe:
709 force_sig(SIGSEGV);
710 }
711
712 #ifdef CONFIG_TRAD_SIGNALS
setup_frame(void * sig_return,struct ksignal * ksig,struct pt_regs * regs,sigset_t * set)713 static int setup_frame(void *sig_return, struct ksignal *ksig,
714 struct pt_regs *regs, sigset_t *set)
715 {
716 struct sigframe __user *frame;
717 int err = 0;
718
719 frame = get_sigframe(ksig, regs, sizeof(*frame));
720 if (!access_ok(frame, sizeof (*frame)))
721 return -EFAULT;
722
723 err |= setup_sigcontext(regs, &frame->sf_sc);
724 err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
725 if (err)
726 return -EFAULT;
727
728 /*
729 * Arguments to signal handler:
730 *
731 * a0 = signal number
732 * a1 = 0 (should be cause)
733 * a2 = pointer to struct sigcontext
734 *
735 * $25 and c0_epc point to the signal handler, $29 points to the
736 * struct sigframe.
737 */
738 regs->regs[ 4] = ksig->sig;
739 regs->regs[ 5] = 0;
740 regs->regs[ 6] = (unsigned long) &frame->sf_sc;
741 regs->regs[29] = (unsigned long) frame;
742 regs->regs[31] = (unsigned long) sig_return;
743 regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
744
745 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
746 current->comm, current->pid,
747 frame, regs->cp0_epc, regs->regs[31]);
748 return 0;
749 }
750 #endif
751
setup_rt_frame(void * sig_return,struct ksignal * ksig,struct pt_regs * regs,sigset_t * set)752 static int setup_rt_frame(void *sig_return, struct ksignal *ksig,
753 struct pt_regs *regs, sigset_t *set)
754 {
755 struct rt_sigframe __user *frame;
756
757 frame = get_sigframe(ksig, regs, sizeof(*frame));
758 if (!access_ok(frame, sizeof (*frame)))
759 return -EFAULT;
760
761 /* Create siginfo. */
762 if (copy_siginfo_to_user(&frame->rs_info, &ksig->info))
763 return -EFAULT;
764
765 /* Create the ucontext. */
766 if (__put_user(0, &frame->rs_uc.uc_flags))
767 return -EFAULT;
768 if (__put_user(NULL, &frame->rs_uc.uc_link))
769 return -EFAULT;
770 if (__save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]))
771 return -EFAULT;
772 if (setup_sigcontext(regs, &frame->rs_uc.uc_mcontext))
773 return -EFAULT;
774 if (__copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set)))
775 return -EFAULT;
776
777 /*
778 * Arguments to signal handler:
779 *
780 * a0 = signal number
781 * a1 = 0 (should be cause)
782 * a2 = pointer to ucontext
783 *
784 * $25 and c0_epc point to the signal handler, $29 points to
785 * the struct rt_sigframe.
786 */
787 regs->regs[ 4] = ksig->sig;
788 regs->regs[ 5] = (unsigned long) &frame->rs_info;
789 regs->regs[ 6] = (unsigned long) &frame->rs_uc;
790 regs->regs[29] = (unsigned long) frame;
791 regs->regs[31] = (unsigned long) sig_return;
792 regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
793
794 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
795 current->comm, current->pid,
796 frame, regs->cp0_epc, regs->regs[31]);
797
798 return 0;
799 }
800
801 struct mips_abi mips_abi = {
802 #ifdef CONFIG_TRAD_SIGNALS
803 .setup_frame = setup_frame,
804 #endif
805 .setup_rt_frame = setup_rt_frame,
806 .restart = __NR_restart_syscall,
807
808 .off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
809 .off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
810 .off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
811
812 .vdso = &vdso_image,
813 };
814
handle_signal(struct ksignal * ksig,struct pt_regs * regs)815 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
816 {
817 sigset_t *oldset = sigmask_to_save();
818 int ret;
819 struct mips_abi *abi = current->thread.abi;
820 void *vdso = current->mm->context.vdso;
821
822 /*
823 * If we were emulating a delay slot instruction, exit that frame such
824 * that addresses in the sigframe are as expected for userland and we
825 * don't have a problem if we reuse the thread's frame for an
826 * instruction within the signal handler.
827 */
828 dsemul_thread_rollback(regs);
829
830 if (regs->regs[0]) {
831 switch(regs->regs[2]) {
832 case ERESTART_RESTARTBLOCK:
833 case ERESTARTNOHAND:
834 regs->regs[2] = EINTR;
835 break;
836 case ERESTARTSYS:
837 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
838 regs->regs[2] = EINTR;
839 break;
840 }
841 fallthrough;
842 case ERESTARTNOINTR:
843 regs->regs[7] = regs->regs[26];
844 regs->regs[2] = regs->regs[0];
845 regs->cp0_epc -= 4;
846 }
847
848 regs->regs[0] = 0; /* Don't deal with this again. */
849 }
850
851 rseq_signal_deliver(ksig, regs);
852
853 if (sig_uses_siginfo(&ksig->ka, abi))
854 ret = abi->setup_rt_frame(vdso + abi->vdso->off_rt_sigreturn,
855 ksig, regs, oldset);
856 else
857 ret = abi->setup_frame(vdso + abi->vdso->off_sigreturn,
858 ksig, regs, oldset);
859
860 signal_setup_done(ret, ksig, 0);
861 }
862
do_signal(struct pt_regs * regs)863 static void do_signal(struct pt_regs *regs)
864 {
865 struct ksignal ksig;
866
867 if (get_signal(&ksig)) {
868 /* Whee! Actually deliver the signal. */
869 handle_signal(&ksig, regs);
870 return;
871 }
872
873 if (regs->regs[0]) {
874 switch (regs->regs[2]) {
875 case ERESTARTNOHAND:
876 case ERESTARTSYS:
877 case ERESTARTNOINTR:
878 regs->regs[2] = regs->regs[0];
879 regs->regs[7] = regs->regs[26];
880 regs->cp0_epc -= 4;
881 break;
882
883 case ERESTART_RESTARTBLOCK:
884 regs->regs[2] = current->thread.abi->restart;
885 regs->regs[7] = regs->regs[26];
886 regs->cp0_epc -= 4;
887 break;
888 }
889 regs->regs[0] = 0; /* Don't deal with this again. */
890 }
891
892 /*
893 * If there's no signal to deliver, we just put the saved sigmask
894 * back
895 */
896 restore_saved_sigmask();
897 }
898
899 /*
900 * notification of userspace execution resumption
901 * - triggered by the TIF_WORK_MASK flags
902 */
do_notify_resume(struct pt_regs * regs,void * unused,__u32 thread_info_flags)903 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
904 __u32 thread_info_flags)
905 {
906 local_irq_enable();
907
908 user_exit();
909
910 if (thread_info_flags & _TIF_UPROBE)
911 uprobe_notify_resume(regs);
912
913 /* deal with pending signal delivery */
914 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
915 do_signal(regs);
916
917 if (thread_info_flags & _TIF_NOTIFY_RESUME)
918 resume_user_mode_work(regs);
919
920 user_enter();
921 }
922
923 #if defined(CONFIG_SMP) && defined(CONFIG_MIPS_FP_SUPPORT)
smp_save_fp_context(void __user * sc)924 static int smp_save_fp_context(void __user *sc)
925 {
926 return raw_cpu_has_fpu
927 ? save_hw_fp_context(sc)
928 : copy_fp_to_sigcontext(sc);
929 }
930
smp_restore_fp_context(void __user * sc)931 static int smp_restore_fp_context(void __user *sc)
932 {
933 return raw_cpu_has_fpu
934 ? restore_hw_fp_context(sc)
935 : copy_fp_from_sigcontext(sc);
936 }
937 #endif
938
signal_setup(void)939 static int signal_setup(void)
940 {
941 /*
942 * The offset from sigcontext to extended context should be the same
943 * regardless of the type of signal, such that userland can always know
944 * where to look if it wishes to find the extended context structures.
945 */
946 BUILD_BUG_ON((offsetof(struct sigframe, sf_extcontext) -
947 offsetof(struct sigframe, sf_sc)) !=
948 (offsetof(struct rt_sigframe, rs_uc.uc_extcontext) -
949 offsetof(struct rt_sigframe, rs_uc.uc_mcontext)));
950
951 #if defined(CONFIG_SMP) && defined(CONFIG_MIPS_FP_SUPPORT)
952 /* For now just do the cpu_has_fpu check when the functions are invoked */
953 save_fp_context = smp_save_fp_context;
954 restore_fp_context = smp_restore_fp_context;
955 #else
956 if (cpu_has_fpu) {
957 save_fp_context = save_hw_fp_context;
958 restore_fp_context = restore_hw_fp_context;
959 } else {
960 save_fp_context = copy_fp_to_sigcontext;
961 restore_fp_context = copy_fp_from_sigcontext;
962 }
963 #endif /* CONFIG_SMP */
964
965 return 0;
966 }
967
968 arch_initcall(signal_setup);
969