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   1 /*  $Id: signal.c,v 1.60 2002/02/09 19:49:31 davem Exp $
   2  *  arch/sparc64/kernel/signal.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *  Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
   6  *  Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
   7  *  Copyright (C) 1997 Eddie C. Dost   (ecd@skynet.be)
   8  *  Copyright (C) 1997,1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
   9  */
  10
  11 #ifdef CONFIG_COMPAT
  12 #include <linux/compat.h>       /* for compat_old_sigset_t */
  13 #endif
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/signal.h>
  17 #include <linux/errno.h>
  18 #include <linux/wait.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/unistd.h>
  21 #include <linux/mm.h>
  22 #include <linux/tty.h>
  23 #include <linux/binfmts.h>
  24 #include <linux/bitops.h>
  25
  26 #include <asm/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
  34 #include "entry.h"
  35 #include "systbls.h"
  36
  37 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  38
  39 /* {set, get}context() needed for 64-bit SparcLinux userland. */
  40 asmlinkage void sparc64_set_context(struct pt_regs *regs)
  41 {
  42         struct ucontext __user *ucp = (struct ucontext __user *)
  43                 regs->u_regs[UREG_I0];
  44         mc_gregset_t __user *grp;
  45         unsigned long pc, npc, tstate;
  46         unsigned long fp, i7;
  47         unsigned char fenab;
  48         int err;
  49
  50         flush_user_windows();
  51         if (get_thread_wsaved()                                 ||
  52             (((unsigned long)ucp) & (sizeof(unsigned long)-1))  ||
  53             (!__access_ok(ucp, sizeof(*ucp))))
  54                 goto do_sigsegv;
  55         grp  = &ucp->uc_mcontext.mc_gregs;
  56         err  = __get_user(pc, &((*grp)[MC_PC]));
  57         err |= __get_user(npc, &((*grp)[MC_NPC]));
  58         if (err || ((pc | npc) & 3))
  59                 goto do_sigsegv;
  60         if (regs->u_regs[UREG_I1]) {
  61                 sigset_t set;
  62
  63                 if (_NSIG_WORDS == 1) {
  64                         if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0]))
  65                                 goto do_sigsegv;
  66                 } else {
  67                         if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t)))
  68                                 goto do_sigsegv;
  69                 }
  70                 sigdelsetmask(&set, ~_BLOCKABLE);
  71                 spin_lock_irq(&current->sighand->siglock);
  72                 current->blocked = set;
  73                 recalc_sigpending();
  74                 spin_unlock_irq(&current->sighand->siglock);
  75         }
  76         if (test_thread_flag(TIF_32BIT)) {
  77                 pc &= 0xffffffff;
  78                 npc &= 0xffffffff;
  79         }
  80         regs->tpc = pc;
  81         regs->tnpc = npc;
  82         err |= __get_user(regs->y, &((*grp)[MC_Y]));
  83         err |= __get_user(tstate, &((*grp)[MC_TSTATE]));
  84         regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
  85         regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
  86         err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1]));
  87         err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2]));
  88         err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3]));
  89         err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4]));
  90         err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5]));
  91         err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6]));
  92         err |= __get_user(regs->u_regs[UREG_G7], (&(*grp)[MC_G7]));
  93         err |= __get_user(regs->u_regs[UREG_I0], (&(*grp)[MC_O0]));
  94         err |= __get_user(regs->u_regs[UREG_I1], (&(*grp)[MC_O1]));
  95         err |= __get_user(regs->u_regs[UREG_I2], (&(*grp)[MC_O2]));
  96         err |= __get_user(regs->u_regs[UREG_I3], (&(*grp)[MC_O3]));
  97         err |= __get_user(regs->u_regs[UREG_I4], (&(*grp)[MC_O4]));
  98         err |= __get_user(regs->u_regs[UREG_I5], (&(*grp)[MC_O5]));
  99         err |= __get_user(regs->u_regs[UREG_I6], (&(*grp)[MC_O6]));
 100         err |= __get_user(regs->u_regs[UREG_I7], (&(*grp)[MC_O7]));
 101
 102         err |= __get_user(fp, &(ucp->uc_mcontext.mc_fp));
 103         err |= __get_user(i7, &(ucp->uc_mcontext.mc_i7));
 104         err |= __put_user(fp,
 105               (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
 106         err |= __put_user(i7,
 107               (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
 108
 109         err |= __get_user(fenab, &(ucp->uc_mcontext.mc_fpregs.mcfpu_enab));
 110         if (fenab) {
 111                 unsigned long *fpregs = current_thread_info()->fpregs;
 112                 unsigned long fprs;
 113
 114                 fprs_write(0);
 115                 err |= __get_user(fprs, &(ucp->uc_mcontext.mc_fpregs.mcfpu_fprs));
 116                 if (fprs & FPRS_DL)
 117                         err |= copy_from_user(fpregs,
 118                                               &(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs),
 119                                               (sizeof(unsigned int) * 32));
 120                 if (fprs & FPRS_DU)
 121                         err |= copy_from_user(fpregs+16,
 122                          ((unsigned long __user *)&(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs))+16,
 123                          (sizeof(unsigned int) * 32));
 124                 err |= __get_user(current_thread_info()->xfsr[0],
 125                                   &(ucp->uc_mcontext.mc_fpregs.mcfpu_fsr));
 126                 err |= __get_user(current_thread_info()->gsr[0],
 127                                   &(ucp->uc_mcontext.mc_fpregs.mcfpu_gsr));
 128                 regs->tstate &= ~TSTATE_PEF;
 129         }
 130         if (err)
 131                 goto do_sigsegv;
 132
 133         return;
 134 do_sigsegv:
 135         force_sig(SIGSEGV, current);
 136 }
 137
 138 asmlinkage void sparc64_get_context(struct pt_regs *regs)
 139 {
 140         struct ucontext __user *ucp = (struct ucontext __user *)
 141                 regs->u_regs[UREG_I0];
 142         mc_gregset_t __user *grp;
 143         mcontext_t __user *mcp;
 144         unsigned long fp, i7;
 145         unsigned char fenab;
 146         int err;
 147
 148         synchronize_user_stack();
 149         if (get_thread_wsaved() || clear_user(ucp, sizeof(*ucp)))
 150                 goto do_sigsegv;
 151
 152 #if 1
 153         fenab = 0; /* IMO get_context is like any other system call, thus modifies FPU state -jj */
 154 #else
 155         fenab = (current_thread_info()->fpsaved[0] & FPRS_FEF);
 156 #endif
 157
 158         mcp = &ucp->uc_mcontext;
 159         grp = &mcp->mc_gregs;
 160
 161         /* Skip over the trap instruction, first. */
 162         if (test_thread_flag(TIF_32BIT)) {
 163                 regs->tpc   = (regs->tnpc & 0xffffffff);
 164                 regs->tnpc  = (regs->tnpc + 4) & 0xffffffff;
 165         } else {
 166                 regs->tpc   = regs->tnpc;
 167                 regs->tnpc += 4;
 168         }
 169         err = 0;
 170         if (_NSIG_WORDS == 1)
 171                 err |= __put_user(current->blocked.sig[0],
 172                                   (unsigned long __user *)&ucp->uc_sigmask);
 173         else
 174                 err |= __copy_to_user(&ucp->uc_sigmask, &current->blocked,
 175                                       sizeof(sigset_t));
 176
 177         err |= __put_user(regs->tstate, &((*grp)[MC_TSTATE]));
 178         err |= __put_user(regs->tpc, &((*grp)[MC_PC]));
 179         err |= __put_user(regs->tnpc, &((*grp)[MC_NPC]));
 180         err |= __put_user(regs->y, &((*grp)[MC_Y]));
 181         err |= __put_user(regs->u_regs[UREG_G1], &((*grp)[MC_G1]));
 182         err |= __put_user(regs->u_regs[UREG_G2], &((*grp)[MC_G2]));
 183         err |= __put_user(regs->u_regs[UREG_G3], &((*grp)[MC_G3]));
 184         err |= __put_user(regs->u_regs[UREG_G4], &((*grp)[MC_G4]));
 185         err |= __put_user(regs->u_regs[UREG_G5], &((*grp)[MC_G5]));
 186         err |= __put_user(regs->u_regs[UREG_G6], &((*grp)[MC_G6]));
 187         err |= __put_user(regs->u_regs[UREG_G7], &((*grp)[MC_G7]));
 188         err |= __put_user(regs->u_regs[UREG_I0], &((*grp)[MC_O0]));
 189         err |= __put_user(regs->u_regs[UREG_I1], &((*grp)[MC_O1]));
 190         err |= __put_user(regs->u_regs[UREG_I2], &((*grp)[MC_O2]));
 191         err |= __put_user(regs->u_regs[UREG_I3], &((*grp)[MC_O3]));
 192         err |= __put_user(regs->u_regs[UREG_I4], &((*grp)[MC_O4]));
 193         err |= __put_user(regs->u_regs[UREG_I5], &((*grp)[MC_O5]));
 194         err |= __put_user(regs->u_regs[UREG_I6], &((*grp)[MC_O6]));
 195         err |= __put_user(regs->u_regs[UREG_I7], &((*grp)[MC_O7]));
 196
 197         err |= __get_user(fp,
 198                  (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
 199         err |= __get_user(i7,
 200                  (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
 201         err |= __put_user(fp, &(mcp->mc_fp));
 202         err |= __put_user(i7, &(mcp->mc_i7));
 203
 204         err |= __put_user(fenab, &(mcp->mc_fpregs.mcfpu_enab));
 205         if (fenab) {
 206                 unsigned long *fpregs = current_thread_info()->fpregs;
 207                 unsigned long fprs;
 208
 209                 fprs = current_thread_info()->fpsaved[0];
 210                 if (fprs & FPRS_DL)
 211                         err |= copy_to_user(&(mcp->mc_fpregs.mcfpu_fregs), fpregs,
 212                                             (sizeof(unsigned int) * 32));
 213                 if (fprs & FPRS_DU)
 214                         err |= copy_to_user(
 215                           ((unsigned long __user *)&(mcp->mc_fpregs.mcfpu_fregs))+16, fpregs+16,
 216                           (sizeof(unsigned int) * 32));
 217                 err |= __put_user(current_thread_info()->xfsr[0], &(mcp->mc_fpregs.mcfpu_fsr));
 218                 err |= __put_user(current_thread_info()->gsr[0], &(mcp->mc_fpregs.mcfpu_gsr));
 219                 err |= __put_user(fprs, &(mcp->mc_fpregs.mcfpu_fprs));
 220         }
 221         if (err)
 222                 goto do_sigsegv;
 223
 224         return;
 225 do_sigsegv:
 226         force_sig(SIGSEGV, current);
 227 }
 228
 229 struct rt_signal_frame {
 230         struct sparc_stackf     ss;
 231         siginfo_t               info;
 232         struct pt_regs          regs;
 233         __siginfo_fpu_t __user  *fpu_save;
 234         stack_t                 stack;
 235         sigset_t                mask;
 236         __siginfo_fpu_t         fpu_state;
 237 };
 238
 239 static long _sigpause_common(old_sigset_t set)
 240 {
 241         set &= _BLOCKABLE;
 242         spin_lock_irq(&current->sighand->siglock);
 243         current->saved_sigmask = current->blocked;
 244         siginitset(&current->blocked, set);
 245         recalc_sigpending();
 246         spin_unlock_irq(&current->sighand->siglock);
 247
 248         current->state = TASK_INTERRUPTIBLE;
 249         schedule();
 250
 251         set_restore_sigmask();
 252
 253         return -ERESTARTNOHAND;
 254 }
 255
 256 asmlinkage long sys_sigpause(unsigned int set)
 257 {
 258         return _sigpause_common(set);
 259 }
 260
 261 asmlinkage long sys_sigsuspend(old_sigset_t set)
 262 {
 263         return _sigpause_common(set);
 264 }
 265
 266 static inline int
 267 restore_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
 268 {
 269         unsigned long *fpregs = current_thread_info()->fpregs;
 270         unsigned long fprs;
 271         int err;
 272
 273         err = __get_user(fprs, &fpu->si_fprs);
 274         fprs_write(0);
 275         regs->tstate &= ~TSTATE_PEF;
 276         if (fprs & FPRS_DL)
 277                 err |= copy_from_user(fpregs, &fpu->si_float_regs[0],
 278                                (sizeof(unsigned int) * 32));
 279         if (fprs & FPRS_DU)
 280                 err |= copy_from_user(fpregs+16, &fpu->si_float_regs[32],
 281                                (sizeof(unsigned int) * 32));
 282         err |= __get_user(current_thread_info()->xfsr[0], &fpu->si_fsr);
 283         err |= __get_user(current_thread_info()->gsr[0], &fpu->si_gsr);
 284         current_thread_info()->fpsaved[0] |= fprs;
 285         return err;
 286 }
 287
 288 void do_rt_sigreturn(struct pt_regs *regs)
 289 {
 290         struct rt_signal_frame __user *sf;
 291         unsigned long tpc, tnpc, tstate;
 292         __siginfo_fpu_t __user *fpu_save;
 293         sigset_t set;
 294         int err;
 295
 296         /* Always make any pending restarted system calls return -EINTR */
 297         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 298
 299         synchronize_user_stack ();
 300         sf = (struct rt_signal_frame __user *)
 301                 (regs->u_regs [UREG_FP] + STACK_BIAS);
 302
 303         /* 1. Make sure we are not getting garbage from the user */
 304         if (((unsigned long) sf) & 3)
 305                 goto segv;
 306
 307         err = get_user(tpc, &sf->regs.tpc);
 308         err |= __get_user(tnpc, &sf->regs.tnpc);
 309         if (test_thread_flag(TIF_32BIT)) {
 310                 tpc &= 0xffffffff;
 311                 tnpc &= 0xffffffff;
 312         }
 313         err |= ((tpc | tnpc) & 3);
 314
 315         /* 2. Restore the state */
 316         err |= __get_user(regs->y, &sf->regs.y);
 317         err |= __get_user(tstate, &sf->regs.tstate);
 318         err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs));
 319
 320         /* User can only change condition codes and %asi in %tstate. */
 321         regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
 322         regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
 323
 324         err |= __get_user(fpu_save, &sf->fpu_save);
 325         if (fpu_save)
 326                 err |= restore_fpu_state(regs, &sf->fpu_state);
 327
 328         err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
 329         err |= do_sigaltstack(&sf->stack, NULL, (unsigned long)sf);
 330
 331         if (err)
 332                 goto segv;
 333
 334         regs->tpc = tpc;
 335         regs->tnpc = tnpc;
 336
 337         /* Prevent syscall restart.  */
 338         pt_regs_clear_syscall(regs);
 339
 340         sigdelsetmask(&set, ~_BLOCKABLE);
 341         spin_lock_irq(&current->sighand->siglock);
 342         current->blocked = set;
 343         recalc_sigpending();
 344         spin_unlock_irq(&current->sighand->siglock);
 345         return;
 346 segv:
 347         force_sig(SIGSEGV, current);
 348 }
 349
 350 /* Checks if the fp is valid */
 351 static int invalid_frame_pointer(void __user *fp, int fplen)
 352 {
 353         if (((unsigned long) fp) & 7)
 354                 return 1;
 355         return 0;
 356 }
 357
 358 static inline int
 359 save_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
 360 {
 361         unsigned long *fpregs = current_thread_info()->fpregs;
 362         unsigned long fprs;
 363         int err = 0;
 364
 365         fprs = current_thread_info()->fpsaved[0];
 366         if (fprs & FPRS_DL)
 367                 err |= copy_to_user(&fpu->si_float_regs[0], fpregs,
 368                                     (sizeof(unsigned int) * 32));
 369         if (fprs & FPRS_DU)
 370                 err |= copy_to_user(&fpu->si_float_regs[32], fpregs+16,
 371                                     (sizeof(unsigned int) * 32));
 372         err |= __put_user(current_thread_info()->xfsr[0], &fpu->si_fsr);
 373         err |= __put_user(current_thread_info()->gsr[0], &fpu->si_gsr);
 374         err |= __put_user(fprs, &fpu->si_fprs);
 375
 376         return err;
 377 }
 378
 379 static inline void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, unsigned long framesize)
 380 {
 381         unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS;
 382
 383         /*
 384          * If we are on the alternate signal stack and would overflow it, don't.
 385          * Return an always-bogus address instead so we will die with SIGSEGV.
 386          */
 387         if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
 388                 return (void __user *) -1L;
 389
 390         /* This is the X/Open sanctioned signal stack switching.  */
 391         if (ka->sa.sa_flags & SA_ONSTACK) {
 392                 if (sas_ss_flags(sp) == 0)
 393                         sp = current->sas_ss_sp + current->sas_ss_size;
 394         }
 395
 396         /* Always align the stack frame.  This handles two cases.  First,
 397          * sigaltstack need not be mindful of platform specific stack
 398          * alignment.  Second, if we took this signal because the stack
 399          * is not aligned properly, we'd like to take the signal cleanly
 400          * and report that.
 401          */
 402         sp &= ~7UL;
 403
 404         return (void __user *)(sp - framesize);
 405 }
 406
 407 static inline void
 408 setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
 409                int signo, sigset_t *oldset, siginfo_t *info)
 410 {
 411         struct rt_signal_frame __user *sf;
 412         int sigframe_size, err;
 413
 414         /* 1. Make sure everything is clean */
 415         synchronize_user_stack();
 416         save_and_clear_fpu();
 417
 418         sigframe_size = sizeof(struct rt_signal_frame);
 419         if (!(current_thread_info()->fpsaved[0] & FPRS_FEF))
 420                 sigframe_size -= sizeof(__siginfo_fpu_t);
 421
 422         sf = (struct rt_signal_frame __user *)
 423                 get_sigframe(ka, regs, sigframe_size);
 424
 425         if (invalid_frame_pointer (sf, sigframe_size))
 426                 goto sigill;
 427
 428         if (get_thread_wsaved() != 0)
 429                 goto sigill;
 430
 431         /* 2. Save the current process state */
 432         err = copy_to_user(&sf->regs, regs, sizeof (*regs));
 433
 434         if (current_thread_info()->fpsaved[0] & FPRS_FEF) {
 435                 err |= save_fpu_state(regs, &sf->fpu_state);
 436                 err |= __put_user((u64)&sf->fpu_state, &sf->fpu_save);
 437         } else {
 438                 err |= __put_user(0, &sf->fpu_save);
 439         }
 440
 441         /* Setup sigaltstack */
 442         err |= __put_user(current->sas_ss_sp, &sf->stack.ss_sp);
 443         err |= __put_user(sas_ss_flags(regs->u_regs[UREG_FP]), &sf->stack.ss_flags);
 444         err |= __put_user(current->sas_ss_size, &sf->stack.ss_size);
 445
 446         err |= copy_to_user(&sf->mask, oldset, sizeof(sigset_t));
 447
 448         err |= copy_in_user((u64 __user *)sf,
 449                             (u64 __user *)(regs->u_regs[UREG_FP]+STACK_BIAS),
 450                             sizeof(struct reg_window));
 451
 452         if (info)
 453                 err |= copy_siginfo_to_user(&sf->info, info);
 454         else {
 455                 err |= __put_user(signo, &sf->info.si_signo);
 456                 err |= __put_user(SI_NOINFO, &sf->info.si_code);
 457         }
 458         if (err)
 459                 goto sigsegv;
 460
 461         /* 3. signal handler back-trampoline and parameters */
 462         regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;
 463         regs->u_regs[UREG_I0] = signo;
 464         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
 465
 466         /* The sigcontext is passed in this way because of how it
 467          * is defined in GLIBC's /usr/include/bits/sigcontext.h
 468          * for sparc64.  It includes the 128 bytes of siginfo_t.
 469          */
 470         regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
 471
 472         /* 5. signal handler */
 473         regs->tpc = (unsigned long) ka->sa.sa_handler;
 474         regs->tnpc = (regs->tpc + 4);
 475         if (test_thread_flag(TIF_32BIT)) {
 476                 regs->tpc &= 0xffffffff;
 477                 regs->tnpc &= 0xffffffff;
 478         }
 479         /* 4. return to kernel instructions */
 480         regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
 481         return;
 482
 483 sigill:
 484         do_exit(SIGILL);
 485 sigsegv:
 486         force_sigsegv(signo, current);
 487 }
 488
 489 static inline void handle_signal(unsigned long signr, struct k_sigaction *ka,
 490                                  siginfo_t *info,
 491                                  sigset_t *oldset, struct pt_regs *regs)
 492 {
 493         setup_rt_frame(ka, regs, signr, oldset,
 494                        (ka->sa.sa_flags & SA_SIGINFO) ? info : NULL);
 495         spin_lock_irq(&current->sighand->siglock);
 496         sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 497         if (!(ka->sa.sa_flags & SA_NOMASK))
 498                 sigaddset(&current->blocked,signr);
 499         recalc_sigpending();
 500         spin_unlock_irq(&current->sighand->siglock);
 501 }
 502
 503 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
 504                                    struct sigaction *sa)
 505 {
 506         switch (regs->u_regs[UREG_I0]) {
 507         case ERESTART_RESTARTBLOCK:
 508         case ERESTARTNOHAND:
 509         no_system_call_restart:
 510                 regs->u_regs[UREG_I0] = EINTR;
 511                 regs->tstate |= (TSTATE_ICARRY|TSTATE_XCARRY);
 512                 break;
 513         case ERESTARTSYS:
 514                 if (!(sa->sa_flags & SA_RESTART))
 515                         goto no_system_call_restart;
 516                 /* fallthrough */
 517         case ERESTARTNOINTR:
 518                 regs->u_regs[UREG_I0] = orig_i0;
 519                 regs->tpc -= 4;
 520                 regs->tnpc -= 4;
 521         }
 522 }
 523
 524 /* Note that 'init' is a special process: it doesn't get signals it doesn't
 525  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 526  * mistake.
 527  */
 528 static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
 529 {
 530         struct k_sigaction ka;
 531         int restart_syscall;
 532         sigset_t *oldset;
 533         siginfo_t info;
 534         int signr;
 535
 536         if (pt_regs_is_syscall(regs) &&
 537             (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) {
 538                 restart_syscall = 1;
 539         } else
 540                 restart_syscall = 0;
 541
 542         if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 543                 oldset = &current->saved_sigmask;
 544         else
 545                 oldset = &current->blocked;
 546
 547 #ifdef CONFIG_COMPAT
 548         if (test_thread_flag(TIF_32BIT)) {
 549                 extern void do_signal32(sigset_t *, struct pt_regs *,
 550                                         int restart_syscall,
 551                                         unsigned long orig_i0);
 552                 do_signal32(oldset, regs, restart_syscall, orig_i0);
 553                 return;
 554         }
 555 #endif
 556
 557         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 558
 559         /* If the debugger messes with the program counter, it clears
 560          * the software "in syscall" bit, directing us to not perform
 561          * a syscall restart.
 562          */
 563         if (restart_syscall && !pt_regs_is_syscall(regs))
 564                 restart_syscall = 0;
 565
 566         if (signr > 0) {
 567                 if (restart_syscall)
 568                         syscall_restart(orig_i0, regs, &ka.sa);
 569                 handle_signal(signr, &ka, &info, oldset, regs);
 570
 571                 /* A signal was successfully delivered; the saved
 572                  * sigmask will have been stored in the signal frame,
 573                  * and will be restored by sigreturn, so we can simply
 574                  * clear the TS_RESTORE_SIGMASK flag.
 575                  */
 576                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 577                 return;
 578         }
 579         if (restart_syscall &&
 580             (regs->u_regs[UREG_I0] == ERESTARTNOHAND ||
 581              regs->u_regs[UREG_I0] == ERESTARTSYS ||
 582              regs->u_regs[UREG_I0] == ERESTARTNOINTR)) {
 583                 /* replay the system call when we are done */
 584                 regs->u_regs[UREG_I0] = orig_i0;
 585                 regs->tpc -= 4;
 586                 regs->tnpc -= 4;
 587         }
 588         if (restart_syscall &&
 589             regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
 590                 regs->u_regs[UREG_G1] = __NR_restart_syscall;
 591                 regs->tpc -= 4;
 592                 regs->tnpc -= 4;
 593         }
 594
 595         /* If there's no signal to deliver, we just put the saved sigmask
 596          * back
 597          */
 598         if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 599                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 600                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 601         }
 602 }
 603
 604 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags)
 605 {
 606         if (thread_info_flags & _TIF_SIGPENDING)
 607                 do_signal(regs, orig_i0);
 608 }