arch/sparc/kernel/signal_64.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  arch/sparc64/kernel/signal.c
   4  *
   5  *  Copyright (C) 1991, 1992  Linus Torvalds
   6  *  Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
   7  *  Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
   8  *  Copyright (C) 1997 Eddie C. Dost   (ecd@skynet.be)
   9  *  Copyright (C) 1997,1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
  10  */
  11
  12 #include <linux/sched.h>
  13 #include <linux/kernel.h>
  14 #include <linux/signal.h>
  15 #include <linux/errno.h>
  16 #include <linux/wait.h>
  17 #include <linux/ptrace.h>
  18 #include <linux/tracehook.h>
  19 #include <linux/unistd.h>
  20 #include <linux/mm.h>
  21 #include <linux/tty.h>
  22 #include <linux/binfmts.h>
  23 #include <linux/bitops.h>
  24 #include <linux/context_tracking.h>
  25
  26 #include <linux/uaccess.h>
  27 #include <asm/ptrace.h>
  28 #include <asm/pgtable.h>
  29 #include <asm/fpumacro.h>
  30 #include <asm/uctx.h>
  31 #include <asm/siginfo.h>
  32 #include <asm/visasm.h>
  33 #include <asm/switch_to.h>
  34 #include <asm/cacheflush.h>
  35
  36 #include "sigutil.h"
  37 #include "systbls.h"
  38 #include "kernel.h"
  39 #include "entry.h"
  40
  41 /* {set, get}context() needed for 64-bit SparcLinux userland. */
  42 asmlinkage void sparc64_set_context(struct pt_regs *regs)
  43 {
  44         struct ucontext __user *ucp = (struct ucontext __user *)
  45                 regs->u_regs[UREG_I0];
  46         enum ctx_state prev_state = exception_enter();
  47         mc_gregset_t __user *grp;
  48         unsigned long pc, npc, tstate;
  49         unsigned long fp, i7;
  50         unsigned char fenab;
  51         int err;
  52
  53         synchronize_user_stack();
  54         if (get_thread_wsaved()                                 ||
  55             (((unsigned long)ucp) & (sizeof(unsigned long)-1))  ||
  56             (!__access_ok(ucp, sizeof(*ucp))))
  57                 goto do_sigsegv;
  58         grp  = &ucp->uc_mcontext.mc_gregs;
  59         err  = __get_user(pc, &((*grp)[MC_PC]));
  60         err |= __get_user(npc, &((*grp)[MC_NPC]));
  61         if (err || ((pc | npc) & 3))
  62                 goto do_sigsegv;
  63         if (regs->u_regs[UREG_I1]) {
  64                 sigset_t set;
  65
  66                 if (_NSIG_WORDS == 1) {
  67                         if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0]))
  68                                 goto do_sigsegv;
  69                 } else {
  70                         if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t)))
  71                                 goto do_sigsegv;
  72                 }
  73                 set_current_blocked(&set);
  74         }
  75         if (test_thread_flag(TIF_32BIT)) {
  76                 pc &= 0xffffffff;
  77                 npc &= 0xffffffff;
  78         }
  79         regs->tpc = pc;
  80         regs->tnpc = npc;
  81         err |= __get_user(regs->y, &((*grp)[MC_Y]));
  82         err |= __get_user(tstate, &((*grp)[MC_TSTATE]));
  83         regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
  84         regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
  85         err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1]));
  86         err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2]));
  87         err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3]));
  88         err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4]));
  89         err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5]));
  90         err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6]));
  91
  92         /* Skip %g7 as that's the thread register in userspace.  */
  93
  94         err |= __get_user(regs->u_regs[UREG_I0], (&(*grp)[MC_O0]));
  95         err |= __get_user(regs->u_regs[UREG_I1], (&(*grp)[MC_O1]));
  96         err |= __get_user(regs->u_regs[UREG_I2], (&(*grp)[MC_O2]));
  97         err |= __get_user(regs->u_regs[UREG_I3], (&(*grp)[MC_O3]));
  98         err |= __get_user(regs->u_regs[UREG_I4], (&(*grp)[MC_O4]));
  99         err |= __get_user(regs->u_regs[UREG_I5], (&(*grp)[MC_O5]));
 100         err |= __get_user(regs->u_regs[UREG_I6], (&(*grp)[MC_O6]));
 101         err |= __get_user(regs->u_regs[UREG_I7], (&(*grp)[MC_O7]));
 102
 103         err |= __get_user(fp, &(ucp->uc_mcontext.mc_fp));
 104         err |= __get_user(i7, &(ucp->uc_mcontext.mc_i7));
 105         err |= __put_user(fp,
 106               (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
 107         err |= __put_user(i7,
 108               (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
 109
 110         err |= __get_user(fenab, &(ucp->uc_mcontext.mc_fpregs.mcfpu_enab));
 111         if (fenab) {
 112                 unsigned long *fpregs = current_thread_info()->fpregs;
 113                 unsigned long fprs;
 114
 115                 fprs_write(0);
 116                 err |= __get_user(fprs, &(ucp->uc_mcontext.mc_fpregs.mcfpu_fprs));
 117                 if (fprs & FPRS_DL)
 118                         err |= copy_from_user(fpregs,
 119                                               &(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs),
 120                                               (sizeof(unsigned int) * 32));
 121                 if (fprs & FPRS_DU)
 122                         err |= copy_from_user(fpregs+16,
 123                          ((unsigned long __user *)&(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs))+16,
 124                          (sizeof(unsigned int) * 32));
 125                 err |= __get_user(current_thread_info()->xfsr[0],
 126                                   &(ucp->uc_mcontext.mc_fpregs.mcfpu_fsr));
 127                 err |= __get_user(current_thread_info()->gsr[0],
 128                                   &(ucp->uc_mcontext.mc_fpregs.mcfpu_gsr));
 129                 regs->tstate &= ~TSTATE_PEF;
 130         }
 131         if (err)
 132                 goto do_sigsegv;
 133 out:
 134         exception_exit(prev_state);
 135         return;
 136 do_sigsegv:
 137         force_sig(SIGSEGV, current);
 138         goto out;
 139 }
 140
 141 asmlinkage void sparc64_get_context(struct pt_regs *regs)
 142 {
 143         struct ucontext __user *ucp = (struct ucontext __user *)
 144                 regs->u_regs[UREG_I0];
 145         enum ctx_state prev_state = exception_enter();
 146         mc_gregset_t __user *grp;
 147         mcontext_t __user *mcp;
 148         unsigned long fp, i7;
 149         unsigned char fenab;
 150         int err;
 151
 152         synchronize_user_stack();
 153         if (get_thread_wsaved() || clear_user(ucp, sizeof(*ucp)))
 154                 goto do_sigsegv;
 155
 156 #if 1
 157         fenab = 0; /* IMO get_context is like any other system call, thus modifies FPU state -jj */
 158 #else
 159         fenab = (current_thread_info()->fpsaved[0] & FPRS_FEF);
 160 #endif
 161
 162         mcp = &ucp->uc_mcontext;
 163         grp = &mcp->mc_gregs;
 164
 165         /* Skip over the trap instruction, first. */
 166         if (test_thread_flag(TIF_32BIT)) {
 167                 regs->tpc   = (regs->tnpc & 0xffffffff);
 168                 regs->tnpc  = (regs->tnpc + 4) & 0xffffffff;
 169         } else {
 170                 regs->tpc   = regs->tnpc;
 171                 regs->tnpc += 4;
 172         }
 173         err = 0;
 174         if (_NSIG_WORDS == 1)
 175                 err |= __put_user(current->blocked.sig[0],
 176                                   (unsigned long __user *)&ucp->uc_sigmask);
 177         else
 178                 err |= __copy_to_user(&ucp->uc_sigmask, &current->blocked,
 179                                       sizeof(sigset_t));
 180
 181         err |= __put_user(regs->tstate, &((*grp)[MC_TSTATE]));
 182         err |= __put_user(regs->tpc, &((*grp)[MC_PC]));
 183         err |= __put_user(regs->tnpc, &((*grp)[MC_NPC]));
 184         err |= __put_user(regs->y, &((*grp)[MC_Y]));
 185         err |= __put_user(regs->u_regs[UREG_G1], &((*grp)[MC_G1]));
 186         err |= __put_user(regs->u_regs[UREG_G2], &((*grp)[MC_G2]));
 187         err |= __put_user(regs->u_regs[UREG_G3], &((*grp)[MC_G3]));
 188         err |= __put_user(regs->u_regs[UREG_G4], &((*grp)[MC_G4]));
 189         err |= __put_user(regs->u_regs[UREG_G5], &((*grp)[MC_G5]));
 190         err |= __put_user(regs->u_regs[UREG_G6], &((*grp)[MC_G6]));
 191         err |= __put_user(regs->u_regs[UREG_G7], &((*grp)[MC_G7]));
 192         err |= __put_user(regs->u_regs[UREG_I0], &((*grp)[MC_O0]));
 193         err |= __put_user(regs->u_regs[UREG_I1], &((*grp)[MC_O1]));
 194         err |= __put_user(regs->u_regs[UREG_I2], &((*grp)[MC_O2]));
 195         err |= __put_user(regs->u_regs[UREG_I3], &((*grp)[MC_O3]));
 196         err |= __put_user(regs->u_regs[UREG_I4], &((*grp)[MC_O4]));
 197         err |= __put_user(regs->u_regs[UREG_I5], &((*grp)[MC_O5]));
 198         err |= __put_user(regs->u_regs[UREG_I6], &((*grp)[MC_O6]));
 199         err |= __put_user(regs->u_regs[UREG_I7], &((*grp)[MC_O7]));
 200
 201         err |= __get_user(fp,
 202                  (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
 203         err |= __get_user(i7,
 204                  (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
 205         err |= __put_user(fp, &(mcp->mc_fp));
 206         err |= __put_user(i7, &(mcp->mc_i7));
 207
 208         err |= __put_user(fenab, &(mcp->mc_fpregs.mcfpu_enab));
 209         if (fenab) {
 210                 unsigned long *fpregs = current_thread_info()->fpregs;
 211                 unsigned long fprs;
 212
 213                 fprs = current_thread_info()->fpsaved[0];
 214                 if (fprs & FPRS_DL)
 215                         err |= copy_to_user(&(mcp->mc_fpregs.mcfpu_fregs), fpregs,
 216                                             (sizeof(unsigned int) * 32));
 217                 if (fprs & FPRS_DU)
 218                         err |= copy_to_user(
 219                           ((unsigned long __user *)&(mcp->mc_fpregs.mcfpu_fregs))+16, fpregs+16,
 220                           (sizeof(unsigned int) * 32));
 221                 err |= __put_user(current_thread_info()->xfsr[0], &(mcp->mc_fpregs.mcfpu_fsr));
 222                 err |= __put_user(current_thread_info()->gsr[0], &(mcp->mc_fpregs.mcfpu_gsr));
 223                 err |= __put_user(fprs, &(mcp->mc_fpregs.mcfpu_fprs));
 224         }
 225         if (err)
 226                 goto do_sigsegv;
 227 out:
 228         exception_exit(prev_state);
 229         return;
 230 do_sigsegv:
 231         force_sig(SIGSEGV, current);
 232         goto out;
 233 }
 234
 235 /* Checks if the fp is valid.  We always build rt signal frames which
 236  * are 16-byte aligned, therefore we can always enforce that the
 237  * restore frame has that property as well.
 238  */
 239 static bool invalid_frame_pointer(void __user *fp)
 240 {
 241         if (((unsigned long) fp) & 15)
 242                 return true;
 243         return false;
 244 }
 245
 246 struct rt_signal_frame {
 247         struct sparc_stackf     ss;
 248         siginfo_t               info;
 249         struct pt_regs          regs;
 250         __siginfo_fpu_t __user  *fpu_save;
 251         stack_t                 stack;
 252         sigset_t                mask;
 253         __siginfo_rwin_t        *rwin_save;
 254 };
 255
 256 void do_rt_sigreturn(struct pt_regs *regs)
 257 {
 258         unsigned long tpc, tnpc, tstate, ufp;
 259         struct rt_signal_frame __user *sf;
 260         __siginfo_fpu_t __user *fpu_save;
 261         __siginfo_rwin_t __user *rwin_save;
 262         sigset_t set;
 263         int err;
 264
 265         /* Always make any pending restarted system calls return -EINTR */
 266         current->restart_block.fn = do_no_restart_syscall;
 267
 268         synchronize_user_stack ();
 269         sf = (struct rt_signal_frame __user *)
 270                 (regs->u_regs [UREG_FP] + STACK_BIAS);
 271
 272         /* 1. Make sure we are not getting garbage from the user */
 273         if (invalid_frame_pointer(sf))
 274                 goto segv;
 275
 276         if (get_user(ufp, &sf->regs.u_regs[UREG_FP]))
 277                 goto segv;
 278
 279         if ((ufp + STACK_BIAS) & 0x7)
 280                 goto segv;
 281
 282         err = __get_user(tpc, &sf->regs.tpc);
 283         err |= __get_user(tnpc, &sf->regs.tnpc);
 284         if (test_thread_flag(TIF_32BIT)) {
 285                 tpc &= 0xffffffff;
 286                 tnpc &= 0xffffffff;
 287         }
 288         err |= ((tpc | tnpc) & 3);
 289
 290         /* 2. Restore the state */
 291         err |= __get_user(regs->y, &sf->regs.y);
 292         err |= __get_user(tstate, &sf->regs.tstate);
 293         err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs));
 294
 295         /* User can only change condition codes and %asi in %tstate. */
 296         regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
 297         regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
 298
 299         err |= __get_user(fpu_save, &sf->fpu_save);
 300         if (!err && fpu_save)
 301                 err |= restore_fpu_state(regs, fpu_save);
 302
 303         err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
 304         err |= restore_altstack(&sf->stack);
 305         if (err)
 306                 goto segv;
 307
 308         err |= __get_user(rwin_save, &sf->rwin_save);
 309         if (!err && rwin_save) {
 310                 if (restore_rwin_state(rwin_save))
 311                         goto segv;
 312         }
 313
 314         regs->tpc = tpc;
 315         regs->tnpc = tnpc;
 316
 317         /* Prevent syscall restart.  */
 318         pt_regs_clear_syscall(regs);
 319
 320         set_current_blocked(&set);
 321         return;
 322 segv:
 323         force_sig(SIGSEGV, current);
 324 }
 325
 326 static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
 327 {
 328         unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS;
 329
 330         /*
 331          * If we are on the alternate signal stack and would overflow it, don't.
 332          * Return an always-bogus address instead so we will die with SIGSEGV.
 333          */
 334         if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
 335                 return (void __user *) -1L;
 336
 337         /* This is the X/Open sanctioned signal stack switching.  */
 338         sp = sigsp(sp, ksig) - framesize;
 339
 340         /* Always align the stack frame.  This handles two cases.  First,
 341          * sigaltstack need not be mindful of platform specific stack
 342          * alignment.  Second, if we took this signal because the stack
 343          * is not aligned properly, we'd like to take the signal cleanly
 344          * and report that.
 345          */
 346         sp &= ~15UL;
 347
 348         return (void __user *) sp;
 349 }
 350
 351 static inline int
 352 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
 353 {
 354         struct rt_signal_frame __user *sf;
 355         int wsaved, err, sf_size;
 356         void __user *tail;
 357
 358         /* 1. Make sure everything is clean */
 359         synchronize_user_stack();
 360         save_and_clear_fpu();
 361
 362         wsaved = get_thread_wsaved();
 363
 364         sf_size = sizeof(struct rt_signal_frame);
 365         if (current_thread_info()->fpsaved[0] & FPRS_FEF)
 366                 sf_size += sizeof(__siginfo_fpu_t);
 367         if (wsaved)
 368                 sf_size += sizeof(__siginfo_rwin_t);
 369         sf = (struct rt_signal_frame __user *)
 370                 get_sigframe(ksig, regs, sf_size);
 371
 372         if (invalid_frame_pointer (sf)) {
 373                 if (show_unhandled_signals)
 374                         pr_info("%s[%d] bad frame in setup_rt_frame: %016lx TPC %016lx O7 %016lx\n",
 375                                 current->comm, current->pid, (unsigned long)sf,
 376                                 regs->tpc, regs->u_regs[UREG_I7]);
 377                 force_sigsegv(ksig->sig, current);
 378                 return -EINVAL;
 379         }
 380
 381         tail = (sf + 1);
 382
 383         /* 2. Save the current process state */
 384         err = copy_to_user(&sf->regs, regs, sizeof (*regs));
 385
 386         if (current_thread_info()->fpsaved[0] & FPRS_FEF) {
 387                 __siginfo_fpu_t __user *fpu_save = tail;
 388                 tail += sizeof(__siginfo_fpu_t);
 389                 err |= save_fpu_state(regs, fpu_save);
 390                 err |= __put_user((u64)fpu_save, &sf->fpu_save);
 391         } else {
 392                 err |= __put_user(0, &sf->fpu_save);
 393         }
 394         if (wsaved) {
 395                 __siginfo_rwin_t __user *rwin_save = tail;
 396                 tail += sizeof(__siginfo_rwin_t);
 397                 err |= save_rwin_state(wsaved, rwin_save);
 398                 err |= __put_user((u64)rwin_save, &sf->rwin_save);
 399                 set_thread_wsaved(0);
 400         } else {
 401                 err |= __put_user(0, &sf->rwin_save);
 402         }
 403
 404         /* Setup sigaltstack */
 405         err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]);
 406
 407         err |= copy_to_user(&sf->mask, sigmask_to_save(), sizeof(sigset_t));
 408
 409         if (!wsaved) {
 410                 err |= copy_in_user((u64 __user *)sf,
 411                                     (u64 __user *)(regs->u_regs[UREG_FP] +
 412                                                    STACK_BIAS),
 413                                     sizeof(struct reg_window));
 414         } else {
 415                 struct reg_window *rp;
 416
 417                 rp = &current_thread_info()->reg_window[wsaved - 1];
 418                 err |= copy_to_user(sf, rp, sizeof(struct reg_window));
 419         }
 420         if (ksig->ka.sa.sa_flags & SA_SIGINFO)
 421                 err |= copy_siginfo_to_user(&sf->info, &ksig->info);
 422         else {
 423                 err |= __put_user(ksig->sig, &sf->info.si_signo);
 424                 err |= __put_user(SI_NOINFO, &sf->info.si_code);
 425         }
 426         if (err)
 427                 return err;
 428
 429         /* 3. signal handler back-trampoline and parameters */
 430         regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;
 431         regs->u_regs[UREG_I0] = ksig->sig;
 432         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
 433
 434         /* The sigcontext is passed in this way because of how it
 435          * is defined in GLIBC's /usr/include/bits/sigcontext.h
 436          * for sparc64.  It includes the 128 bytes of siginfo_t.
 437          */
 438         regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
 439
 440         /* 5. signal handler */
 441         regs->tpc = (unsigned long) ksig->ka.sa.sa_handler;
 442         regs->tnpc = (regs->tpc + 4);
 443         if (test_thread_flag(TIF_32BIT)) {
 444                 regs->tpc &= 0xffffffff;
 445                 regs->tnpc &= 0xffffffff;
 446         }
 447         /* 4. return to kernel instructions */
 448         regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
 449         return 0;
 450 }
 451
 452 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
 453                                    struct sigaction *sa)
 454 {
 455         switch (regs->u_regs[UREG_I0]) {
 456         case ERESTART_RESTARTBLOCK:
 457         case ERESTARTNOHAND:
 458         no_system_call_restart:
 459                 regs->u_regs[UREG_I0] = EINTR;
 460                 regs->tstate |= (TSTATE_ICARRY|TSTATE_XCARRY);
 461                 break;
 462         case ERESTARTSYS:
 463                 if (!(sa->sa_flags & SA_RESTART))
 464                         goto no_system_call_restart;
 465                 /* fallthrough */
 466         case ERESTARTNOINTR:
 467                 regs->u_regs[UREG_I0] = orig_i0;
 468                 regs->tpc -= 4;
 469                 regs->tnpc -= 4;
 470         }
 471 }
 472
 473 /* Note that 'init' is a special process: it doesn't get signals it doesn't
 474  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 475  * mistake.
 476  */
 477 static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
 478 {
 479         struct ksignal ksig;
 480         int restart_syscall;
 481         bool has_handler;
 482
 483         /* It's a lot of work and synchronization to add a new ptrace
 484          * register for GDB to save and restore in order to get
 485          * orig_i0 correct for syscall restarts when debugging.
 486          *
 487          * Although it should be the case that most of the global
 488          * registers are volatile across a system call, glibc already
 489          * depends upon that fact that we preserve them.  So we can't
 490          * just use any global register to save away the orig_i0 value.
 491          *
 492          * In particular %g2, %g3, %g4, and %g5 are all assumed to be
 493          * preserved across a system call trap by various pieces of
 494          * code in glibc.
 495          *
 496          * %g7 is used as the "thread register".   %g6 is not used in
 497          * any fixed manner.  %g6 is used as a scratch register and
 498          * a compiler temporary, but it's value is never used across
 499          * a system call.  Therefore %g6 is usable for orig_i0 storage.
 500          */
 501         if (pt_regs_is_syscall(regs) &&
 502             (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY)))
 503                 regs->u_regs[UREG_G6] = orig_i0;
 504
 505 #ifdef CONFIG_COMPAT
 506         if (test_thread_flag(TIF_32BIT)) {
 507                 do_signal32(regs);
 508                 return;
 509         }
 510 #endif
 511
 512         has_handler = get_signal(&ksig);
 513
 514         restart_syscall = 0;
 515         if (pt_regs_is_syscall(regs) &&
 516             (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) {
 517                 restart_syscall = 1;
 518                 orig_i0 = regs->u_regs[UREG_G6];
 519         }
 520
 521         if (has_handler) {
 522                 if (restart_syscall)
 523                         syscall_restart(orig_i0, regs, &ksig.ka.sa);
 524                 signal_setup_done(setup_rt_frame(&ksig, regs), &ksig, 0);
 525         } else {
 526                 if (restart_syscall) {
 527                         switch (regs->u_regs[UREG_I0]) {
 528                         case ERESTARTNOHAND:
 529                         case ERESTARTSYS:
 530                         case ERESTARTNOINTR:
 531                                 /* replay the system call when we are done */
 532                                 regs->u_regs[UREG_I0] = orig_i0;
 533                                 regs->tpc -= 4;
 534                                 regs->tnpc -= 4;
 535                                 pt_regs_clear_syscall(regs);
 536                         case ERESTART_RESTARTBLOCK:
 537                                 regs->u_regs[UREG_G1] = __NR_restart_syscall;
 538                                 regs->tpc -= 4;
 539                                 regs->tnpc -= 4;
 540                                 pt_regs_clear_syscall(regs);
 541                         }
 542                 }
 543                 restore_saved_sigmask();
 544         }
 545 }
 546
 547 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags)
 548 {
 549         user_exit();
 550         if (thread_info_flags & _TIF_UPROBE)
 551                 uprobe_notify_resume(regs);
 552         if (thread_info_flags & _TIF_SIGPENDING)
 553                 do_signal(regs, orig_i0);
 554         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 555                 clear_thread_flag(TIF_NOTIFY_RESUME);
 556                 tracehook_notify_resume(regs);
 557         }
 558         user_enter();
 559 }
 560