linux/arch/mips/kernel/signal.c
<<
>>
Prefs
   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
  45static int (*save_fp_context)(void __user *sc);
  46static int (*restore_fp_context)(void __user *sc);
  47
  48struct 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
  58struct 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 */
  71static 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(&current->thread.fpu.fpr[i], 0),
  83                               &fpregs[i]);
  84        }
  85        err |= __put_user(current->thread.fpu.fcr31, csr);
  86
  87        return err;
  88}
  89
  90static 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(&current->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
 111static int copy_fp_to_sigcontext(void __user *sc)
 112{
 113        return 0;
 114}
 115
 116static 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 */
 126static 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
 135static 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
 148static 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
 163static 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(&current->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
 209static 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(&current->thread.fpu.fpr[i], 1, val);
 246                }
 247        }
 248
 249        return err;
 250}
 251
 252#else /* !CONFIG_CPU_HAS_MSA */
 253
 254static int save_msa_extcontext(void __user *buf)
 255{
 256        return 0;
 257}
 258
 259static int restore_msa_extcontext(void __user *buf, unsigned int size)
 260{
 261        return SIGSYS;
 262}
 263
 264#endif /* !CONFIG_CPU_HAS_MSA */
 265
 266static 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
 287static 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 */
 325int 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
 369fp_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
 378int 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
 432fp_done:
 433        if (!err && (used & USED_EXTCONTEXT))
 434                err = restore_extcontext(sc_to_extcontext(sc));
 435
 436        return err ?: sig;
 437}
 438
 439int 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
 475static 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
 497int 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
 516int 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
 554void __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
 582SYSCALL_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
 589SYSCALL_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
 630asmlinkage 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
 662badframe:
 663        force_sig(SIGSEGV);
 664}
 665#endif /* CONFIG_TRAD_SIGNALS */
 666
 667asmlinkage 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
 702badframe:
 703        force_sig(SIGSEGV);
 704}
 705
 706#ifdef CONFIG_TRAD_SIGNALS
 707static 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
 746static 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
 793struct 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
 807static 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
 855static 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 */
 895asmlinkage 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                rseq_handle_notify_resume(NULL, regs);
 912        }
 913
 914        user_enter();
 915}
 916
 917#if defined(CONFIG_SMP) && defined(CONFIG_MIPS_FP_SUPPORT)
 918static int smp_save_fp_context(void __user *sc)
 919{
 920        return raw_cpu_has_fpu
 921               ? save_hw_fp_context(sc)
 922               : copy_fp_to_sigcontext(sc);
 923}
 924
 925static int smp_restore_fp_context(void __user *sc)
 926{
 927        return raw_cpu_has_fpu
 928               ? restore_hw_fp_context(sc)
 929               : copy_fp_from_sigcontext(sc);
 930}
 931#endif
 932
 933static int signal_setup(void)
 934{
 935        /*
 936         * The offset from sigcontext to extended context should be the same
 937         * regardless of the type of signal, such that userland can always know
 938         * where to look if it wishes to find the extended context structures.
 939         */
 940        BUILD_BUG_ON((offsetof(struct sigframe, sf_extcontext) -
 941                      offsetof(struct sigframe, sf_sc)) !=
 942                     (offsetof(struct rt_sigframe, rs_uc.uc_extcontext) -
 943                      offsetof(struct rt_sigframe, rs_uc.uc_mcontext)));
 944
 945#if defined(CONFIG_SMP) && defined(CONFIG_MIPS_FP_SUPPORT)
 946        /* For now just do the cpu_has_fpu check when the functions are invoked */
 947        save_fp_context = smp_save_fp_context;
 948        restore_fp_context = smp_restore_fp_context;
 949#else
 950        if (cpu_has_fpu) {
 951                save_fp_context = save_hw_fp_context;
 952                restore_fp_context = restore_hw_fp_context;
 953        } else {
 954                save_fp_context = copy_fp_to_sigcontext;
 955                restore_fp_context = copy_fp_from_sigcontext;
 956        }
 957#endif /* CONFIG_SMP */
 958
 959        return 0;
 960}
 961
 962arch_initcall(signal_setup);
 963