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 #include <asm/syscalls.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 * If we are on the alternate signal stack and would overflow it, don't.
567 * Return an always-bogus address instead so we will die with SIGSEGV.
568 */
569 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
570 return (void __user __force *)(-1UL);
571
572 /*
573 * FPU emulator may have its own trampoline active just
574 * above the user stack, 16-bytes before the next lowest
575 * 16 byte boundary. Try to avoid trashing it.
576 */
577 sp -= 32;
578
579 sp = sigsp(sp, ksig);
580
581 return (void __user *)((sp - frame_size) & SIGMASK);
582 }
583
584 /*
585 * Atomically swap in the new signal mask, and wait for a signal.
586 */
587
588 #ifdef CONFIG_TRAD_SIGNALS
SYSCALL_DEFINE1(sigsuspend,sigset_t __user *,uset)589 SYSCALL_DEFINE1(sigsuspend, sigset_t __user *, uset)
590 {
591 return sys_rt_sigsuspend(uset, sizeof(sigset_t));
592 }
593 #endif
594
595 #ifdef CONFIG_TRAD_SIGNALS
SYSCALL_DEFINE3(sigaction,int,sig,const struct sigaction __user *,act,struct sigaction __user *,oact)596 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
597 struct sigaction __user *, oact)
598 {
599 struct k_sigaction new_ka, old_ka;
600 int ret;
601 int err = 0;
602
603 if (act) {
604 old_sigset_t mask;
605
606 if (!access_ok(act, sizeof(*act)))
607 return -EFAULT;
608 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
609 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
610 err |= __get_user(mask, &act->sa_mask.sig[0]);
611 if (err)
612 return -EFAULT;
613
614 siginitset(&new_ka.sa.sa_mask, mask);
615 }
616
617 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
618
619 if (!ret && oact) {
620 if (!access_ok(oact, sizeof(*oact)))
621 return -EFAULT;
622 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
623 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
624 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
625 err |= __put_user(0, &oact->sa_mask.sig[1]);
626 err |= __put_user(0, &oact->sa_mask.sig[2]);
627 err |= __put_user(0, &oact->sa_mask.sig[3]);
628 if (err)
629 return -EFAULT;
630 }
631
632 return ret;
633 }
634 #endif
635
636 #ifdef CONFIG_TRAD_SIGNALS
sys_sigreturn(void)637 asmlinkage void sys_sigreturn(void)
638 {
639 struct sigframe __user *frame;
640 struct pt_regs *regs;
641 sigset_t blocked;
642 int sig;
643
644 regs = current_pt_regs();
645 frame = (struct sigframe __user *)regs->regs[29];
646 if (!access_ok(frame, sizeof(*frame)))
647 goto badframe;
648 if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
649 goto badframe;
650
651 set_current_blocked(&blocked);
652
653 sig = restore_sigcontext(regs, &frame->sf_sc);
654 if (sig < 0)
655 goto badframe;
656 else if (sig)
657 force_sig(sig);
658
659 /*
660 * Don't let your children do this ...
661 */
662 __asm__ __volatile__(
663 "move\t$29, %0\n\t"
664 "j\tsyscall_exit"
665 : /* no outputs */
666 : "r" (regs));
667 /* Unreached */
668
669 badframe:
670 force_sig(SIGSEGV);
671 }
672 #endif /* CONFIG_TRAD_SIGNALS */
673
sys_rt_sigreturn(void)674 asmlinkage void sys_rt_sigreturn(void)
675 {
676 struct rt_sigframe __user *frame;
677 struct pt_regs *regs;
678 sigset_t set;
679 int sig;
680
681 regs = current_pt_regs();
682 frame = (struct rt_sigframe __user *)regs->regs[29];
683 if (!access_ok(frame, sizeof(*frame)))
684 goto badframe;
685 if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
686 goto badframe;
687
688 set_current_blocked(&set);
689
690 sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
691 if (sig < 0)
692 goto badframe;
693 else if (sig)
694 force_sig(sig);
695
696 if (restore_altstack(&frame->rs_uc.uc_stack))
697 goto badframe;
698
699 /*
700 * Don't let your children do this ...
701 */
702 __asm__ __volatile__(
703 "move\t$29, %0\n\t"
704 "j\tsyscall_exit"
705 : /* no outputs */
706 : "r" (regs));
707 /* Unreached */
708
709 badframe:
710 force_sig(SIGSEGV);
711 }
712
713 #ifdef CONFIG_TRAD_SIGNALS
setup_frame(void * sig_return,struct ksignal * ksig,struct pt_regs * regs,sigset_t * set)714 static int setup_frame(void *sig_return, struct ksignal *ksig,
715 struct pt_regs *regs, sigset_t *set)
716 {
717 struct sigframe __user *frame;
718 int err = 0;
719
720 frame = get_sigframe(ksig, regs, sizeof(*frame));
721 if (!access_ok(frame, sizeof (*frame)))
722 return -EFAULT;
723
724 err |= setup_sigcontext(regs, &frame->sf_sc);
725 err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
726 if (err)
727 return -EFAULT;
728
729 /*
730 * Arguments to signal handler:
731 *
732 * a0 = signal number
733 * a1 = 0 (should be cause)
734 * a2 = pointer to struct sigcontext
735 *
736 * $25 and c0_epc point to the signal handler, $29 points to the
737 * struct sigframe.
738 */
739 regs->regs[ 4] = ksig->sig;
740 regs->regs[ 5] = 0;
741 regs->regs[ 6] = (unsigned long) &frame->sf_sc;
742 regs->regs[29] = (unsigned long) frame;
743 regs->regs[31] = (unsigned long) sig_return;
744 regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
745
746 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
747 current->comm, current->pid,
748 frame, regs->cp0_epc, regs->regs[31]);
749 return 0;
750 }
751 #endif
752
setup_rt_frame(void * sig_return,struct ksignal * ksig,struct pt_regs * regs,sigset_t * set)753 static int setup_rt_frame(void *sig_return, struct ksignal *ksig,
754 struct pt_regs *regs, sigset_t *set)
755 {
756 struct rt_sigframe __user *frame;
757
758 frame = get_sigframe(ksig, regs, sizeof(*frame));
759 if (!access_ok(frame, sizeof (*frame)))
760 return -EFAULT;
761
762 /* Create siginfo. */
763 if (copy_siginfo_to_user(&frame->rs_info, &ksig->info))
764 return -EFAULT;
765
766 /* Create the ucontext. */
767 if (__put_user(0, &frame->rs_uc.uc_flags))
768 return -EFAULT;
769 if (__put_user(NULL, &frame->rs_uc.uc_link))
770 return -EFAULT;
771 if (__save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]))
772 return -EFAULT;
773 if (setup_sigcontext(regs, &frame->rs_uc.uc_mcontext))
774 return -EFAULT;
775 if (__copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set)))
776 return -EFAULT;
777
778 /*
779 * Arguments to signal handler:
780 *
781 * a0 = signal number
782 * a1 = 0 (should be cause)
783 * a2 = pointer to ucontext
784 *
785 * $25 and c0_epc point to the signal handler, $29 points to
786 * the struct rt_sigframe.
787 */
788 regs->regs[ 4] = ksig->sig;
789 regs->regs[ 5] = (unsigned long) &frame->rs_info;
790 regs->regs[ 6] = (unsigned long) &frame->rs_uc;
791 regs->regs[29] = (unsigned long) frame;
792 regs->regs[31] = (unsigned long) sig_return;
793 regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
794
795 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
796 current->comm, current->pid,
797 frame, regs->cp0_epc, regs->regs[31]);
798
799 return 0;
800 }
801
802 struct mips_abi mips_abi = {
803 #ifdef CONFIG_TRAD_SIGNALS
804 .setup_frame = setup_frame,
805 #endif
806 .setup_rt_frame = setup_rt_frame,
807 .restart = __NR_restart_syscall,
808
809 .off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
810 .off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
811 .off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
812
813 .vdso = &vdso_image,
814 };
815
handle_signal(struct ksignal * ksig,struct pt_regs * regs)816 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
817 {
818 sigset_t *oldset = sigmask_to_save();
819 int ret;
820 struct mips_abi *abi = current->thread.abi;
821 void *vdso = current->mm->context.vdso;
822
823 /*
824 * If we were emulating a delay slot instruction, exit that frame such
825 * that addresses in the sigframe are as expected for userland and we
826 * don't have a problem if we reuse the thread's frame for an
827 * instruction within the signal handler.
828 */
829 dsemul_thread_rollback(regs);
830
831 if (regs->regs[0]) {
832 switch(regs->regs[2]) {
833 case ERESTART_RESTARTBLOCK:
834 case ERESTARTNOHAND:
835 regs->regs[2] = EINTR;
836 break;
837 case ERESTARTSYS:
838 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
839 regs->regs[2] = EINTR;
840 break;
841 }
842 fallthrough;
843 case ERESTARTNOINTR:
844 regs->regs[7] = regs->regs[26];
845 regs->regs[2] = regs->regs[0];
846 regs->cp0_epc -= 4;
847 }
848
849 regs->regs[0] = 0; /* Don't deal with this again. */
850 }
851
852 rseq_signal_deliver(ksig, regs);
853
854 if (sig_uses_siginfo(&ksig->ka, abi))
855 ret = abi->setup_rt_frame(vdso + abi->vdso->off_rt_sigreturn,
856 ksig, regs, oldset);
857 else
858 ret = abi->setup_frame(vdso + abi->vdso->off_sigreturn,
859 ksig, regs, oldset);
860
861 signal_setup_done(ret, ksig, 0);
862 }
863
do_signal(struct pt_regs * regs)864 static void do_signal(struct pt_regs *regs)
865 {
866 struct ksignal ksig;
867
868 if (get_signal(&ksig)) {
869 /* Whee! Actually deliver the signal. */
870 handle_signal(&ksig, regs);
871 return;
872 }
873
874 if (regs->regs[0]) {
875 switch (regs->regs[2]) {
876 case ERESTARTNOHAND:
877 case ERESTARTSYS:
878 case ERESTARTNOINTR:
879 regs->regs[2] = regs->regs[0];
880 regs->regs[7] = regs->regs[26];
881 regs->cp0_epc -= 4;
882 break;
883
884 case ERESTART_RESTARTBLOCK:
885 regs->regs[2] = current->thread.abi->restart;
886 regs->regs[7] = regs->regs[26];
887 regs->cp0_epc -= 4;
888 break;
889 }
890 regs->regs[0] = 0; /* Don't deal with this again. */
891 }
892
893 /*
894 * If there's no signal to deliver, we just put the saved sigmask
895 * back
896 */
897 restore_saved_sigmask();
898 }
899
900 /*
901 * notification of userspace execution resumption
902 * - triggered by the TIF_WORK_MASK flags
903 */
do_notify_resume(struct pt_regs * regs,void * unused,__u32 thread_info_flags)904 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
905 __u32 thread_info_flags)
906 {
907 local_irq_enable();
908
909 user_exit();
910
911 if (thread_info_flags & _TIF_UPROBE)
912 uprobe_notify_resume(regs);
913
914 /* deal with pending signal delivery */
915 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
916 do_signal(regs);
917
918 if (thread_info_flags & _TIF_NOTIFY_RESUME)
919 resume_user_mode_work(regs);
920
921 user_enter();
922 }
923
924 #if defined(CONFIG_SMP) && defined(CONFIG_MIPS_FP_SUPPORT)
smp_save_fp_context(void __user * sc)925 static int smp_save_fp_context(void __user *sc)
926 {
927 return raw_cpu_has_fpu
928 ? save_hw_fp_context(sc)
929 : copy_fp_to_sigcontext(sc);
930 }
931
smp_restore_fp_context(void __user * sc)932 static int smp_restore_fp_context(void __user *sc)
933 {
934 return raw_cpu_has_fpu
935 ? restore_hw_fp_context(sc)
936 : copy_fp_from_sigcontext(sc);
937 }
938 #endif
939
signal_setup(void)940 static int signal_setup(void)
941 {
942 /*
943 * The offset from sigcontext to extended context should be the same
944 * regardless of the type of signal, such that userland can always know
945 * where to look if it wishes to find the extended context structures.
946 */
947 BUILD_BUG_ON((offsetof(struct sigframe, sf_extcontext) -
948 offsetof(struct sigframe, sf_sc)) !=
949 (offsetof(struct rt_sigframe, rs_uc.uc_extcontext) -
950 offsetof(struct rt_sigframe, rs_uc.uc_mcontext)));
951
952 #if defined(CONFIG_SMP) && defined(CONFIG_MIPS_FP_SUPPORT)
953 /* For now just do the cpu_has_fpu check when the functions are invoked */
954 save_fp_context = smp_save_fp_context;
955 restore_fp_context = smp_restore_fp_context;
956 #else
957 if (cpu_has_fpu) {
958 save_fp_context = save_hw_fp_context;
959 restore_fp_context = restore_hw_fp_context;
960 } else {
961 save_fp_context = copy_fp_to_sigcontext;
962 restore_fp_context = copy_fp_from_sigcontext;
963 }
964 #endif /* CONFIG_SMP */
965
966 return 0;
967 }
968
969 arch_initcall(signal_setup);
970