arch/mips/kernel/signal.c

   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/compiler.h>
  25 #include <linux/syscalls.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/tracehook.h>
  28
  29 #include <asm/abi.h>
  30 #include <asm/asm.h>
  31 #include <linux/bitops.h>
  32 #include <asm/cacheflush.h>
  33 #include <asm/fpu.h>
  34 #include <asm/sim.h>
  35 #include <asm/ucontext.h>
  36 #include <asm/cpu-features.h>
  37 #include <asm/war.h>
  38 #include <asm/vdso.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[0];
  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 /*
  66  * Thread saved context copy to/from a signal context presumed to be on the
  67  * user stack, and therefore accessed with appropriate macros from uaccess.h.
  68  */
  69 static int copy_fp_to_sigcontext(void __user *sc)
  70 {
  71         struct mips_abi *abi = current->thread.abi;
  72         uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
  73         uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
  74         int i;
  75         int err = 0;
  76         int inc = test_thread_flag(TIF_32BIT_FPREGS) ? 2 : 1;
  77
  78         for (i = 0; i < NUM_FPU_REGS; i += inc) {
  79                 err |=
  80                     __put_user(get_fpr64(&current->thread.fpu.fpr[i], 0),
  81                                &fpregs[i]);
  82         }
  83         err |= __put_user(current->thread.fpu.fcr31, csr);
  84
  85         return err;
  86 }
  87
  88 static int copy_fp_from_sigcontext(void __user *sc)
  89 {
  90         struct mips_abi *abi = current->thread.abi;
  91         uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
  92         uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
  93         int i;
  94         int err = 0;
  95         int inc = test_thread_flag(TIF_32BIT_FPREGS) ? 2 : 1;
  96         u64 fpr_val;
  97
  98         for (i = 0; i < NUM_FPU_REGS; i += inc) {
  99                 err |= __get_user(fpr_val, &fpregs[i]);
 100                 set_fpr64(&current->thread.fpu.fpr[i], 0, fpr_val);
 101         }
 102         err |= __get_user(current->thread.fpu.fcr31, csr);
 103
 104         return err;
 105 }
 106
 107 /*
 108  * Wrappers for the assembly _{save,restore}_fp_context functions.
 109  */
 110 static int save_hw_fp_context(void __user *sc)
 111 {
 112         struct mips_abi *abi = current->thread.abi;
 113         uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
 114         uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
 115
 116         return _save_fp_context(fpregs, csr);
 117 }
 118
 119 static int restore_hw_fp_context(void __user *sc)
 120 {
 121         struct mips_abi *abi = current->thread.abi;
 122         uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
 123         uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
 124
 125         return _restore_fp_context(fpregs, csr);
 126 }
 127
 128 /*
 129  * Extended context handling.
 130  */
 131
 132 static inline void __user *sc_to_extcontext(void __user *sc)
 133 {
 134         struct ucontext __user *uc;
 135
 136         /*
 137          * We can just pretend the sigcontext is always embedded in a struct
 138          * ucontext here, because the offset from sigcontext to extended
 139          * context is the same in the struct sigframe case.
 140          */
 141         uc = container_of(sc, struct ucontext, uc_mcontext);
 142         return &uc->uc_extcontext;
 143 }
 144
 145 static int save_msa_extcontext(void __user *buf)
 146 {
 147         struct msa_extcontext __user *msa = buf;
 148         uint64_t val;
 149         int i, err;
 150
 151         if (!thread_msa_context_live())
 152                 return 0;
 153
 154         /*
 155          * Ensure that we can't lose the live MSA context between checking
 156          * for it & writing it to memory.
 157          */
 158         preempt_disable();
 159
 160         if (is_msa_enabled()) {
 161                 /*
 162                  * There are no EVA versions of the vector register load/store
 163                  * instructions, so MSA context has to be saved to kernel memory
 164                  * and then copied to user memory. The save to kernel memory
 165                  * should already have been done when handling scalar FP
 166                  * context.
 167                  */
 168                 BUG_ON(config_enabled(CONFIG_EVA));
 169
 170                 err = __put_user(read_msa_csr(), &msa->csr);
 171                 err |= _save_msa_all_upper(&msa->wr);
 172
 173                 preempt_enable();
 174         } else {
 175                 preempt_enable();
 176
 177                 err = __put_user(current->thread.fpu.msacsr, &msa->csr);
 178
 179                 for (i = 0; i < NUM_FPU_REGS; i++) {
 180                         val = get_fpr64(&current->thread.fpu.fpr[i], 1);
 181                         err |= __put_user(val, &msa->wr[i]);
 182                 }
 183         }
 184
 185         err |= __put_user(MSA_EXTCONTEXT_MAGIC, &msa->ext.magic);
 186         err |= __put_user(sizeof(*msa), &msa->ext.size);
 187
 188         return err ? -EFAULT : sizeof(*msa);
 189 }
 190
 191 static int restore_msa_extcontext(void __user *buf, unsigned int size)
 192 {
 193         struct msa_extcontext __user *msa = buf;
 194         unsigned long long val;
 195         unsigned int csr;
 196         int i, err;
 197
 198         if (size != sizeof(*msa))
 199                 return -EINVAL;
 200
 201         err = get_user(csr, &msa->csr);
 202         if (err)
 203                 return err;
 204
 205         preempt_disable();
 206
 207         if (is_msa_enabled()) {
 208                 /*
 209                  * There are no EVA versions of the vector register load/store
 210                  * instructions, so MSA context has to be copied to kernel
 211                  * memory and later loaded to registers. The same is true of
 212                  * scalar FP context, so FPU & MSA should have already been
 213                  * disabled whilst handling scalar FP context.
 214                  */
 215                 BUG_ON(config_enabled(CONFIG_EVA));
 216
 217                 write_msa_csr(csr);
 218                 err |= _restore_msa_all_upper(&msa->wr);
 219                 preempt_enable();
 220         } else {
 221                 preempt_enable();
 222
 223                 current->thread.fpu.msacsr = csr;
 224
 225                 for (i = 0; i < NUM_FPU_REGS; i++) {
 226                         err |= __get_user(val, &msa->wr[i]);
 227                         set_fpr64(&current->thread.fpu.fpr[i], 1, val);
 228                 }
 229         }
 230
 231         return err;
 232 }
 233
 234 static int save_extcontext(void __user *buf)
 235 {
 236         int sz;
 237
 238         sz = save_msa_extcontext(buf);
 239         if (sz < 0)
 240                 return sz;
 241         buf += sz;
 242
 243         /* If no context was saved then trivially return */
 244         if (!sz)
 245                 return 0;
 246
 247         /* Write the end marker */
 248         if (__put_user(END_EXTCONTEXT_MAGIC, (u32 *)buf))
 249                 return -EFAULT;
 250
 251         sz += sizeof(((struct extcontext *)NULL)->magic);
 252         return sz;
 253 }
 254
 255 static int restore_extcontext(void __user *buf)
 256 {
 257         struct extcontext ext;
 258         int err;
 259
 260         while (1) {
 261                 err = __get_user(ext.magic, (unsigned int *)buf);
 262                 if (err)
 263                         return err;
 264
 265                 if (ext.magic == END_EXTCONTEXT_MAGIC)
 266                         return 0;
 267
 268                 err = __get_user(ext.size, (unsigned int *)(buf
 269                         + offsetof(struct extcontext, size)));
 270                 if (err)
 271                         return err;
 272
 273                 switch (ext.magic) {
 274                 case MSA_EXTCONTEXT_MAGIC:
 275                         err = restore_msa_extcontext(buf, ext.size);
 276                         break;
 277
 278                 default:
 279                         err = -EINVAL;
 280                         break;
 281                 }
 282
 283                 if (err)
 284                         return err;
 285
 286                 buf += ext.size;
 287         }
 288 }
 289
 290 /*
 291  * Helper routines
 292  */
 293 int protected_save_fp_context(void __user *sc)
 294 {
 295         struct mips_abi *abi = current->thread.abi;
 296         uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
 297         uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
 298         uint32_t __user *used_math = sc + abi->off_sc_used_math;
 299         unsigned int used, ext_sz;
 300         int err;
 301
 302         used = used_math() ? USED_FP : 0;
 303         if (!used)
 304                 goto fp_done;
 305
 306         if (!test_thread_flag(TIF_32BIT_FPREGS))
 307                 used |= USED_FR1;
 308         if (test_thread_flag(TIF_HYBRID_FPREGS))
 309                 used |= USED_HYBRID_FPRS;
 310
 311         /*
 312          * EVA does not have userland equivalents of ldc1 or sdc1, so
 313          * save to the kernel FP context & copy that to userland below.
 314          */
 315         if (config_enabled(CONFIG_EVA))
 316                 lose_fpu(1);
 317
 318         while (1) {
 319                 lock_fpu_owner();
 320                 if (is_fpu_owner()) {
 321                         err = save_fp_context(sc);
 322                         unlock_fpu_owner();
 323                 } else {
 324                         unlock_fpu_owner();
 325                         err = copy_fp_to_sigcontext(sc);
 326                 }
 327                 if (likely(!err))
 328                         break;
 329                 /* touch the sigcontext and try again */
 330                 err = __put_user(0, &fpregs[0]) |
 331                         __put_user(0, &fpregs[31]) |
 332                         __put_user(0, csr);
 333                 if (err)
 334                         return err;     /* really bad sigcontext */
 335         }
 336
 337 fp_done:
 338         ext_sz = err = save_extcontext(sc_to_extcontext(sc));
 339         if (err < 0)
 340                 return err;
 341         used |= ext_sz ? USED_EXTCONTEXT : 0;
 342
 343         return __put_user(used, used_math);
 344 }
 345
 346 int protected_restore_fp_context(void __user *sc)
 347 {
 348         struct mips_abi *abi = current->thread.abi;
 349         uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
 350         uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
 351         uint32_t __user *used_math = sc + abi->off_sc_used_math;
 352         unsigned int used;
 353         int err, sig = 0, tmp __maybe_unused;
 354
 355         err = __get_user(used, used_math);
 356         conditional_used_math(used & USED_FP);
 357
 358         /*
 359          * The signal handler may have used FPU; give it up if the program
 360          * doesn't want it following sigreturn.
 361          */
 362         if (err || !(used & USED_FP))
 363                 lose_fpu(0);
 364         if (err)
 365                 return err;
 366         if (!(used & USED_FP))
 367                 goto fp_done;
 368
 369         err = sig = fpcsr_pending(csr);
 370         if (err < 0)
 371                 return err;
 372
 373         /*
 374          * EVA does not have userland equivalents of ldc1 or sdc1, so we
 375          * disable the FPU here such that the code below simply copies to
 376          * the kernel FP context.
 377          */
 378         if (config_enabled(CONFIG_EVA))
 379                 lose_fpu(0);
 380
 381         while (1) {
 382                 lock_fpu_owner();
 383                 if (is_fpu_owner()) {
 384                         err = restore_fp_context(sc);
 385                         unlock_fpu_owner();
 386                 } else {
 387                         unlock_fpu_owner();
 388                         err = copy_fp_from_sigcontext(sc);
 389                 }
 390                 if (likely(!err))
 391                         break;
 392                 /* touch the sigcontext and try again */
 393                 err = __get_user(tmp, &fpregs[0]) |
 394                         __get_user(tmp, &fpregs[31]) |
 395                         __get_user(tmp, csr);
 396                 if (err)
 397                         break;  /* really bad sigcontext */
 398         }
 399
 400 fp_done:
 401         if (used & USED_EXTCONTEXT)
 402                 err |= restore_extcontext(sc_to_extcontext(sc));
 403
 404         return err ?: sig;
 405 }
 406
 407 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 408 {
 409         int err = 0;
 410         int i;
 411
 412         err |= __put_user(regs->cp0_epc, &sc->sc_pc);
 413
 414         err |= __put_user(0, &sc->sc_regs[0]);
 415         for (i = 1; i < 32; i++)
 416                 err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
 417
 418 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 419         err |= __put_user(regs->acx, &sc->sc_acx);
 420 #endif
 421         err |= __put_user(regs->hi, &sc->sc_mdhi);
 422         err |= __put_user(regs->lo, &sc->sc_mdlo);
 423         if (cpu_has_dsp) {
 424                 err |= __put_user(mfhi1(), &sc->sc_hi1);
 425                 err |= __put_user(mflo1(), &sc->sc_lo1);
 426                 err |= __put_user(mfhi2(), &sc->sc_hi2);
 427                 err |= __put_user(mflo2(), &sc->sc_lo2);
 428                 err |= __put_user(mfhi3(), &sc->sc_hi3);
 429                 err |= __put_user(mflo3(), &sc->sc_lo3);
 430                 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
 431         }
 432
 433
 434         /*
 435          * Save FPU state to signal context. Signal handler
 436          * will "inherit" current FPU state.
 437          */
 438         err |= protected_save_fp_context(sc);
 439
 440         return err;
 441 }
 442
 443 static size_t extcontext_max_size(void)
 444 {
 445         size_t sz = 0;
 446
 447         /*
 448          * The assumption here is that between this point & the point at which
 449          * the extended context is saved the size of the context should only
 450          * ever be able to shrink (if the task is preempted), but never grow.
 451          * That is, what this function returns is an upper bound on the size of
 452          * the extended context for the current task at the current time.
 453          */
 454
 455         if (thread_msa_context_live())
 456                 sz += sizeof(struct msa_extcontext);
 457
 458         /* If any context is saved then we'll append the end marker */
 459         if (sz)
 460                 sz += sizeof(((struct extcontext *)NULL)->magic);
 461
 462         return sz;
 463 }
 464
 465 int fpcsr_pending(unsigned int __user *fpcsr)
 466 {
 467         int err, sig = 0;
 468         unsigned int csr, enabled;
 469
 470         err = __get_user(csr, fpcsr);
 471         enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
 472         /*
 473          * If the signal handler set some FPU exceptions, clear it and
 474          * send SIGFPE.
 475          */
 476         if (csr & enabled) {
 477                 csr &= ~enabled;
 478                 err |= __put_user(csr, fpcsr);
 479                 sig = SIGFPE;
 480         }
 481         return err ?: sig;
 482 }
 483
 484 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 485 {
 486         unsigned long treg;
 487         int err = 0;
 488         int i;
 489
 490         /* Always make any pending restarted system calls return -EINTR */
 491         current->restart_block.fn = do_no_restart_syscall;
 492
 493         err |= __get_user(regs->cp0_epc, &sc->sc_pc);
 494
 495 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 496         err |= __get_user(regs->acx, &sc->sc_acx);
 497 #endif
 498         err |= __get_user(regs->hi, &sc->sc_mdhi);
 499         err |= __get_user(regs->lo, &sc->sc_mdlo);
 500         if (cpu_has_dsp) {
 501                 err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
 502                 err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
 503                 err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
 504                 err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
 505                 err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
 506                 err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
 507                 err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
 508         }
 509
 510         for (i = 1; i < 32; i++)
 511                 err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
 512
 513         return err ?: protected_restore_fp_context(sc);
 514 }
 515
 516 void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
 517                           size_t frame_size)
 518 {
 519         unsigned long sp;
 520
 521         /* Leave space for potential extended context */
 522         frame_size += extcontext_max_size();
 523
 524         /* Default to using normal stack */
 525         sp = regs->regs[29];
 526
 527         /*
 528          * FPU emulator may have it's own trampoline active just
 529          * above the user stack, 16-bytes before the next lowest
 530          * 16 byte boundary.  Try to avoid trashing it.
 531          */
 532         sp -= 32;
 533
 534         sp = sigsp(sp, ksig);
 535
 536         return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
 537 }
 538
 539 /*
 540  * Atomically swap in the new signal mask, and wait for a signal.
 541  */
 542
 543 #ifdef CONFIG_TRAD_SIGNALS
 544 SYSCALL_DEFINE1(sigsuspend, sigset_t __user *, uset)
 545 {
 546         return sys_rt_sigsuspend(uset, sizeof(sigset_t));
 547 }
 548 #endif
 549
 550 #ifdef CONFIG_TRAD_SIGNALS
 551 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
 552         struct sigaction __user *, oact)
 553 {
 554         struct k_sigaction new_ka, old_ka;
 555         int ret;
 556         int err = 0;
 557
 558         if (act) {
 559                 old_sigset_t mask;
 560
 561                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 562                         return -EFAULT;
 563                 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
 564                 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 565                 err |= __get_user(mask, &act->sa_mask.sig[0]);
 566                 if (err)
 567                         return -EFAULT;
 568
 569                 siginitset(&new_ka.sa.sa_mask, mask);
 570         }
 571
 572         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 573
 574         if (!ret && oact) {
 575                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 576                         return -EFAULT;
 577                 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 578                 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
 579                 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
 580                 err |= __put_user(0, &oact->sa_mask.sig[1]);
 581                 err |= __put_user(0, &oact->sa_mask.sig[2]);
 582                 err |= __put_user(0, &oact->sa_mask.sig[3]);
 583                 if (err)
 584                         return -EFAULT;
 585         }
 586
 587         return ret;
 588 }
 589 #endif
 590
 591 #ifdef CONFIG_TRAD_SIGNALS
 592 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 593 {
 594         struct sigframe __user *frame;
 595         sigset_t blocked;
 596         int sig;
 597
 598         frame = (struct sigframe __user *) regs.regs[29];
 599         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 600                 goto badframe;
 601         if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
 602                 goto badframe;
 603
 604         set_current_blocked(&blocked);
 605
 606         sig = restore_sigcontext(&regs, &frame->sf_sc);
 607         if (sig < 0)
 608                 goto badframe;
 609         else if (sig)
 610                 force_sig(sig, current);
 611
 612         /*
 613          * Don't let your children do this ...
 614          */
 615         __asm__ __volatile__(
 616                 "move\t$29, %0\n\t"
 617                 "j\tsyscall_exit"
 618                 :/* no outputs */
 619                 :"r" (&regs));
 620         /* Unreached */
 621
 622 badframe:
 623         force_sig(SIGSEGV, current);
 624 }
 625 #endif /* CONFIG_TRAD_SIGNALS */
 626
 627 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 628 {
 629         struct rt_sigframe __user *frame;
 630         sigset_t set;
 631         int sig;
 632
 633         frame = (struct rt_sigframe __user *) regs.regs[29];
 634         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 635                 goto badframe;
 636         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 637                 goto badframe;
 638
 639         set_current_blocked(&set);
 640
 641         sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
 642         if (sig < 0)
 643                 goto badframe;
 644         else if (sig)
 645                 force_sig(sig, current);
 646
 647         if (restore_altstack(&frame->rs_uc.uc_stack))
 648                 goto badframe;
 649
 650         /*
 651          * Don't let your children do this ...
 652          */
 653         __asm__ __volatile__(
 654                 "move\t$29, %0\n\t"
 655                 "j\tsyscall_exit"
 656                 :/* no outputs */
 657                 :"r" (&regs));
 658         /* Unreached */
 659
 660 badframe:
 661         force_sig(SIGSEGV, current);
 662 }
 663
 664 #ifdef CONFIG_TRAD_SIGNALS
 665 static int setup_frame(void *sig_return, struct ksignal *ksig,
 666                        struct pt_regs *regs, sigset_t *set)
 667 {
 668         struct sigframe __user *frame;
 669         int err = 0;
 670
 671         frame = get_sigframe(ksig, regs, sizeof(*frame));
 672         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 673                 return -EFAULT;
 674
 675         err |= setup_sigcontext(regs, &frame->sf_sc);
 676         err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
 677         if (err)
 678                 return -EFAULT;
 679
 680         /*
 681          * Arguments to signal handler:
 682          *
 683          *   a0 = signal number
 684          *   a1 = 0 (should be cause)
 685          *   a2 = pointer to struct sigcontext
 686          *
 687          * $25 and c0_epc point to the signal handler, $29 points to the
 688          * struct sigframe.
 689          */
 690         regs->regs[ 4] = ksig->sig;
 691         regs->regs[ 5] = 0;
 692         regs->regs[ 6] = (unsigned long) &frame->sf_sc;
 693         regs->regs[29] = (unsigned long) frame;
 694         regs->regs[31] = (unsigned long) sig_return;
 695         regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
 696
 697         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 698                current->comm, current->pid,
 699                frame, regs->cp0_epc, regs->regs[31]);
 700         return 0;
 701 }
 702 #endif
 703
 704 static int setup_rt_frame(void *sig_return, struct ksignal *ksig,
 705                           struct pt_regs *regs, sigset_t *set)
 706 {
 707         struct rt_sigframe __user *frame;
 708         int err = 0;
 709
 710         frame = get_sigframe(ksig, regs, sizeof(*frame));
 711         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 712                 return -EFAULT;
 713
 714         /* Create siginfo.  */
 715         err |= copy_siginfo_to_user(&frame->rs_info, &ksig->info);
 716
 717         /* Create the ucontext.  */
 718         err |= __put_user(0, &frame->rs_uc.uc_flags);
 719         err |= __put_user(NULL, &frame->rs_uc.uc_link);
 720         err |= __save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
 721         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 722         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 723
 724         if (err)
 725                 return -EFAULT;
 726
 727         /*
 728          * Arguments to signal handler:
 729          *
 730          *   a0 = signal number
 731          *   a1 = 0 (should be cause)
 732          *   a2 = pointer to ucontext
 733          *
 734          * $25 and c0_epc point to the signal handler, $29 points to
 735          * the struct rt_sigframe.
 736          */
 737         regs->regs[ 4] = ksig->sig;
 738         regs->regs[ 5] = (unsigned long) &frame->rs_info;
 739         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 740         regs->regs[29] = (unsigned long) frame;
 741         regs->regs[31] = (unsigned long) sig_return;
 742         regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
 743
 744         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 745                current->comm, current->pid,
 746                frame, regs->cp0_epc, regs->regs[31]);
 747
 748         return 0;
 749 }
 750
 751 struct mips_abi mips_abi = {
 752 #ifdef CONFIG_TRAD_SIGNALS
 753         .setup_frame    = setup_frame,
 754         .signal_return_offset = offsetof(struct mips_vdso, signal_trampoline),
 755 #endif
 756         .setup_rt_frame = setup_rt_frame,
 757         .rt_signal_return_offset =
 758                 offsetof(struct mips_vdso, rt_signal_trampoline),
 759         .restart        = __NR_restart_syscall,
 760
 761         .off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
 762         .off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
 763         .off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
 764 };
 765
 766 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 767 {
 768         sigset_t *oldset = sigmask_to_save();
 769         int ret;
 770         struct mips_abi *abi = current->thread.abi;
 771 #ifdef CONFIG_CPU_MICROMIPS
 772         void *vdso;
 773         unsigned long tmp = (unsigned long)current->mm->context.vdso;
 774
 775         set_isa16_mode(tmp);
 776         vdso = (void *)tmp;
 777 #else
 778         void *vdso = current->mm->context.vdso;
 779 #endif
 780
 781         if (regs->regs[0]) {
 782                 switch(regs->regs[2]) {
 783                 case ERESTART_RESTARTBLOCK:
 784                 case ERESTARTNOHAND:
 785                         regs->regs[2] = EINTR;
 786                         break;
 787                 case ERESTARTSYS:
 788                         if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
 789                                 regs->regs[2] = EINTR;
 790                                 break;
 791                         }
 792                 /* fallthrough */
 793                 case ERESTARTNOINTR:
 794                         regs->regs[7] = regs->regs[26];
 795                         regs->regs[2] = regs->regs[0];
 796                         regs->cp0_epc -= 4;
 797                 }
 798
 799                 regs->regs[0] = 0;              /* Don't deal with this again.  */
 800         }
 801
 802         if (sig_uses_siginfo(&ksig->ka))
 803                 ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset,
 804                                           ksig, regs, oldset);
 805         else
 806                 ret = abi->setup_frame(vdso + abi->signal_return_offset, ksig,
 807                                        regs, oldset);
 808
 809         signal_setup_done(ret, ksig, 0);
 810 }
 811
 812 static void do_signal(struct pt_regs *regs)
 813 {
 814         struct ksignal ksig;
 815
 816         if (get_signal(&ksig)) {
 817                 /* Whee!  Actually deliver the signal.  */
 818                 handle_signal(&ksig, regs);
 819                 return;
 820         }
 821
 822         if (regs->regs[0]) {
 823                 switch (regs->regs[2]) {
 824                 case ERESTARTNOHAND:
 825                 case ERESTARTSYS:
 826                 case ERESTARTNOINTR:
 827                         regs->regs[2] = regs->regs[0];
 828                         regs->regs[7] = regs->regs[26];
 829                         regs->cp0_epc -= 4;
 830                         break;
 831
 832                 case ERESTART_RESTARTBLOCK:
 833                         regs->regs[2] = current->thread.abi->restart;
 834                         regs->regs[7] = regs->regs[26];
 835                         regs->cp0_epc -= 4;
 836                         break;
 837                 }
 838                 regs->regs[0] = 0;      /* Don't deal with this again.  */
 839         }
 840
 841         /*
 842          * If there's no signal to deliver, we just put the saved sigmask
 843          * back
 844          */
 845         restore_saved_sigmask();
 846 }
 847
 848 /*
 849  * notification of userspace execution resumption
 850  * - triggered by the TIF_WORK_MASK flags
 851  */
 852 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 853         __u32 thread_info_flags)
 854 {
 855         local_irq_enable();
 856
 857         user_exit();
 858
 859         /* deal with pending signal delivery */
 860         if (thread_info_flags & _TIF_SIGPENDING)
 861                 do_signal(regs);
 862
 863         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 864                 clear_thread_flag(TIF_NOTIFY_RESUME);
 865                 tracehook_notify_resume(regs);
 866         }
 867
 868         user_enter();
 869 }
 870
 871 #ifdef CONFIG_SMP
 872 static int smp_save_fp_context(void __user *sc)
 873 {
 874         return raw_cpu_has_fpu
 875                ? save_hw_fp_context(sc)
 876                : copy_fp_to_sigcontext(sc);
 877 }
 878
 879 static int smp_restore_fp_context(void __user *sc)
 880 {
 881         return raw_cpu_has_fpu
 882                ? restore_hw_fp_context(sc)
 883                : copy_fp_from_sigcontext(sc);
 884 }
 885 #endif
 886
 887 static int signal_setup(void)
 888 {
 889         /*
 890          * The offset from sigcontext to extended context should be the same
 891          * regardless of the type of signal, such that userland can always know
 892          * where to look if it wishes to find the extended context structures.
 893          */
 894         BUILD_BUG_ON((offsetof(struct sigframe, sf_extcontext) -
 895                       offsetof(struct sigframe, sf_sc)) !=
 896                      (offsetof(struct rt_sigframe, rs_uc.uc_extcontext) -
 897                       offsetof(struct rt_sigframe, rs_uc.uc_mcontext)));
 898
 899 #ifdef CONFIG_SMP
 900         /* For now just do the cpu_has_fpu check when the functions are invoked */
 901         save_fp_context = smp_save_fp_context;
 902         restore_fp_context = smp_restore_fp_context;
 903 #else
 904         if (cpu_has_fpu) {
 905                 save_fp_context = save_hw_fp_context;
 906                 restore_fp_context = restore_hw_fp_context;
 907         } else {
 908                 save_fp_context = copy_fp_to_sigcontext;
 909                 restore_fp_context = copy_fp_from_sigcontext;
 910         }
 911 #endif /* CONFIG_SMP */
 912
 913         return 0;
 914 }
 915
 916 arch_initcall(signal_setup);