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