arch/sparc64/kernel/signal.c

   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_SPARC32_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/svr4.h>
  29 #include <asm/pgtable.h>
  30 #include <asm/fpumacro.h>
  31 #include <asm/uctx.h>
  32 #include <asm/siginfo.h>
  33 #include <asm/visasm.h>
  34
  35 #include "entry.h"
  36 #include "systbls.h"
  37
  38 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  39
  40 /* {set, get}context() needed for 64-bit SparcLinux userland. */
  41 asmlinkage void sparc64_set_context(struct pt_regs *regs)
  42 {
  43         struct ucontext __user *ucp = (struct ucontext __user *)
  44                 regs->u_regs[UREG_I0];
  45         mc_gregset_t __user *grp;
  46         unsigned long pc, npc, tstate;
  47         unsigned long fp, i7;
  48         unsigned char fenab;
  49         int err;
  50
  51         flush_user_windows();
  52         if (get_thread_wsaved()                                 ||
  53             (((unsigned long)ucp) & (sizeof(unsigned long)-1))  ||
  54             (!__access_ok(ucp, sizeof(*ucp))))
  55                 goto do_sigsegv;
  56         grp  = &ucp->uc_mcontext.mc_gregs;
  57         err  = __get_user(pc, &((*grp)[MC_PC]));
  58         err |= __get_user(npc, &((*grp)[MC_NPC]));
  59         if (err || ((pc | npc) & 3))
  60                 goto do_sigsegv;
  61         if (regs->u_regs[UREG_I1]) {
  62                 sigset_t set;
  63
  64                 if (_NSIG_WORDS == 1) {
  65                         if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0]))
  66                                 goto do_sigsegv;
  67                 } else {
  68                         if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t)))
  69                                 goto do_sigsegv;
  70                 }
  71                 sigdelsetmask(&set, ~_BLOCKABLE);
  72                 spin_lock_irq(&current->sighand->siglock);
  73                 current->blocked = set;
  74                 recalc_sigpending();
  75                 spin_unlock_irq(&current->sighand->siglock);
  76         }
  77         if (test_thread_flag(TIF_32BIT)) {
  78                 pc &= 0xffffffff;
  79                 npc &= 0xffffffff;
  80         }
  81         regs->tpc = pc;
  82         regs->tnpc = npc;
  83         err |= __get_user(regs->y, &((*grp)[MC_Y]));
  84         err |= __get_user(tstate, &((*grp)[MC_TSTATE]));
  85         regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
  86         regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
  87         err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1]));
  88         err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2]));
  89         err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3]));
  90         err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4]));
  91         err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5]));
  92         err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6]));
  93         err |= __get_user(regs->u_regs[UREG_G7], (&(*grp)[MC_G7]));
  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
 134         return;
 135 do_sigsegv:
 136         force_sig(SIGSEGV, current);
 137 }
 138
 139 asmlinkage void sparc64_get_context(struct pt_regs *regs)
 140 {
 141         struct ucontext __user *ucp = (struct ucontext __user *)
 142                 regs->u_regs[UREG_I0];
 143         mc_gregset_t __user *grp;
 144         mcontext_t __user *mcp;
 145         unsigned long fp, i7;
 146         unsigned char fenab;
 147         int err;
 148
 149         synchronize_user_stack();
 150         if (get_thread_wsaved() || clear_user(ucp, sizeof(*ucp)))
 151                 goto do_sigsegv;
 152
 153 #if 1
 154         fenab = 0; /* IMO get_context is like any other system call, thus modifies FPU state -jj */
 155 #else
 156         fenab = (current_thread_info()->fpsaved[0] & FPRS_FEF);
 157 #endif
 158
 159         mcp = &ucp->uc_mcontext;
 160         grp = &mcp->mc_gregs;
 161
 162         /* Skip over the trap instruction, first. */
 163         if (test_thread_flag(TIF_32BIT)) {
 164                 regs->tpc   = (regs->tnpc & 0xffffffff);
 165                 regs->tnpc  = (regs->tnpc + 4) & 0xffffffff;
 166         } else {
 167                 regs->tpc   = regs->tnpc;
 168                 regs->tnpc += 4;
 169         }
 170         err = 0;
 171         if (_NSIG_WORDS == 1)
 172                 err |= __put_user(current->blocked.sig[0],
 173                                   (unsigned long __user *)&ucp->uc_sigmask);
 174         else
 175                 err |= __copy_to_user(&ucp->uc_sigmask, &current->blocked,
 176                                       sizeof(sigset_t));
 177
 178         err |= __put_user(regs->tstate, &((*grp)[MC_TSTATE]));
 179         err |= __put_user(regs->tpc, &((*grp)[MC_PC]));
 180         err |= __put_user(regs->tnpc, &((*grp)[MC_NPC]));
 181         err |= __put_user(regs->y, &((*grp)[MC_Y]));
 182         err |= __put_user(regs->u_regs[UREG_G1], &((*grp)[MC_G1]));
 183         err |= __put_user(regs->u_regs[UREG_G2], &((*grp)[MC_G2]));
 184         err |= __put_user(regs->u_regs[UREG_G3], &((*grp)[MC_G3]));
 185         err |= __put_user(regs->u_regs[UREG_G4], &((*grp)[MC_G4]));
 186         err |= __put_user(regs->u_regs[UREG_G5], &((*grp)[MC_G5]));
 187         err |= __put_user(regs->u_regs[UREG_G6], &((*grp)[MC_G6]));
 188         err |= __put_user(regs->u_regs[UREG_G7], &((*grp)[MC_G7]));
 189         err |= __put_user(regs->u_regs[UREG_I0], &((*grp)[MC_O0]));
 190         err |= __put_user(regs->u_regs[UREG_I1], &((*grp)[MC_O1]));
 191         err |= __put_user(regs->u_regs[UREG_I2], &((*grp)[MC_O2]));
 192         err |= __put_user(regs->u_regs[UREG_I3], &((*grp)[MC_O3]));
 193         err |= __put_user(regs->u_regs[UREG_I4], &((*grp)[MC_O4]));
 194         err |= __put_user(regs->u_regs[UREG_I5], &((*grp)[MC_O5]));
 195         err |= __put_user(regs->u_regs[UREG_I6], &((*grp)[MC_O6]));
 196         err |= __put_user(regs->u_regs[UREG_I7], &((*grp)[MC_O7]));
 197
 198         err |= __get_user(fp,
 199                  (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
 200         err |= __get_user(i7,
 201                  (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
 202         err |= __put_user(fp, &(mcp->mc_fp));
 203         err |= __put_user(i7, &(mcp->mc_i7));
 204
 205         err |= __put_user(fenab, &(mcp->mc_fpregs.mcfpu_enab));
 206         if (fenab) {
 207                 unsigned long *fpregs = current_thread_info()->fpregs;
 208                 unsigned long fprs;
 209
 210                 fprs = current_thread_info()->fpsaved[0];
 211                 if (fprs & FPRS_DL)
 212                         err |= copy_to_user(&(mcp->mc_fpregs.mcfpu_fregs), fpregs,
 213                                             (sizeof(unsigned int) * 32));
 214                 if (fprs & FPRS_DU)
 215                         err |= copy_to_user(
 216                           ((unsigned long __user *)&(mcp->mc_fpregs.mcfpu_fregs))+16, fpregs+16,
 217                           (sizeof(unsigned int) * 32));
 218                 err |= __put_user(current_thread_info()->xfsr[0], &(mcp->mc_fpregs.mcfpu_fsr));
 219                 err |= __put_user(current_thread_info()->gsr[0], &(mcp->mc_fpregs.mcfpu_gsr));
 220                 err |= __put_user(fprs, &(mcp->mc_fpregs.mcfpu_fprs));
 221         }
 222         if (err)
 223                 goto do_sigsegv;
 224
 225         return;
 226 do_sigsegv:
 227         force_sig(SIGSEGV, current);
 228 }
 229
 230 struct rt_signal_frame {
 231         struct sparc_stackf     ss;
 232         siginfo_t               info;
 233         struct pt_regs          regs;
 234         __siginfo_fpu_t __user  *fpu_save;
 235         stack_t                 stack;
 236         sigset_t                mask;
 237         __siginfo_fpu_t         fpu_state;
 238 };
 239
 240 /* Align macros */
 241 #define RT_ALIGNEDSZ  (((sizeof(struct rt_signal_frame) + 7) & (~7)))
 242
 243 static long _sigpause_common(old_sigset_t set)
 244 {
 245         set &= _BLOCKABLE;
 246         spin_lock_irq(&current->sighand->siglock);
 247         current->saved_sigmask = current->blocked;
 248         siginitset(&current->blocked, set);
 249         recalc_sigpending();
 250         spin_unlock_irq(&current->sighand->siglock);
 251
 252         current->state = TASK_INTERRUPTIBLE;
 253         schedule();
 254         set_thread_flag(TIF_RESTORE_SIGMASK);
 255         return -ERESTARTNOHAND;
 256 }
 257
 258 asmlinkage long sys_sigpause(unsigned int set)
 259 {
 260         return _sigpause_common(set);
 261 }
 262
 263 asmlinkage long sys_sigsuspend(old_sigset_t set)
 264 {
 265         return _sigpause_common(set);
 266 }
 267
 268 static inline int
 269 restore_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
 270 {
 271         unsigned long *fpregs = current_thread_info()->fpregs;
 272         unsigned long fprs;
 273         int err;
 274
 275         err = __get_user(fprs, &fpu->si_fprs);
 276         fprs_write(0);
 277         regs->tstate &= ~TSTATE_PEF;
 278         if (fprs & FPRS_DL)
 279                 err |= copy_from_user(fpregs, &fpu->si_float_regs[0],
 280                                (sizeof(unsigned int) * 32));
 281         if (fprs & FPRS_DU)
 282                 err |= copy_from_user(fpregs+16, &fpu->si_float_regs[32],
 283                                (sizeof(unsigned int) * 32));
 284         err |= __get_user(current_thread_info()->xfsr[0], &fpu->si_fsr);
 285         err |= __get_user(current_thread_info()->gsr[0], &fpu->si_gsr);
 286         current_thread_info()->fpsaved[0] |= fprs;
 287         return err;
 288 }
 289
 290 void do_rt_sigreturn(struct pt_regs *regs)
 291 {
 292         struct rt_signal_frame __user *sf;
 293         unsigned long tpc, tnpc, tstate;
 294         __siginfo_fpu_t __user *fpu_save;
 295         sigset_t set;
 296         int err;
 297
 298         /* Always make any pending restarted system calls return -EINTR */
 299         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 300
 301         synchronize_user_stack ();
 302         sf = (struct rt_signal_frame __user *)
 303                 (regs->u_regs [UREG_FP] + STACK_BIAS);
 304
 305         /* 1. Make sure we are not getting garbage from the user */
 306         if (((unsigned long) sf) & 3)
 307                 goto segv;
 308
 309         err = get_user(tpc, &sf->regs.tpc);
 310         err |= __get_user(tnpc, &sf->regs.tnpc);
 311         if (test_thread_flag(TIF_32BIT)) {
 312                 tpc &= 0xffffffff;
 313                 tnpc &= 0xffffffff;
 314         }
 315         err |= ((tpc | tnpc) & 3);
 316
 317         /* 2. Restore the state */
 318         err |= __get_user(regs->y, &sf->regs.y);
 319         err |= __get_user(tstate, &sf->regs.tstate);
 320         err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs));
 321
 322         /* User can only change condition codes and %asi in %tstate. */
 323         regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
 324         regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
 325
 326         err |= __get_user(fpu_save, &sf->fpu_save);
 327         if (fpu_save)
 328                 err |= restore_fpu_state(regs, &sf->fpu_state);
 329
 330         err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
 331         err |= do_sigaltstack(&sf->stack, NULL, (unsigned long)sf);
 332
 333         if (err)
 334                 goto segv;
 335
 336         regs->tpc = tpc;
 337         regs->tnpc = tnpc;
 338
 339         sigdelsetmask(&set, ~_BLOCKABLE);
 340         spin_lock_irq(&current->sighand->siglock);
 341         current->blocked = set;
 342         recalc_sigpending();
 343         spin_unlock_irq(&current->sighand->siglock);
 344         return;
 345 segv:
 346         force_sig(SIGSEGV, current);
 347 }
 348
 349 /* Checks if the fp is valid */
 350 static int invalid_frame_pointer(void __user *fp, int fplen)
 351 {
 352         if (((unsigned long) fp) & 7)
 353                 return 1;
 354         return 0;
 355 }
 356
 357 static inline int
 358 save_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
 359 {
 360         unsigned long *fpregs = (unsigned long *)(regs+1);
 361         unsigned long fprs;
 362         int err = 0;
 363
 364         fprs = current_thread_info()->fpsaved[0];
 365         if (fprs & FPRS_DL)
 366                 err |= copy_to_user(&fpu->si_float_regs[0], fpregs,
 367                                     (sizeof(unsigned int) * 32));
 368         if (fprs & FPRS_DU)
 369                 err |= copy_to_user(&fpu->si_float_regs[32], fpregs+16,
 370                                     (sizeof(unsigned int) * 32));
 371         err |= __put_user(current_thread_info()->xfsr[0], &fpu->si_fsr);
 372         err |= __put_user(current_thread_info()->gsr[0], &fpu->si_gsr);
 373         err |= __put_user(fprs, &fpu->si_fprs);
 374
 375         return err;
 376 }
 377
 378 static inline void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, unsigned long framesize)
 379 {
 380         unsigned long sp;
 381
 382         sp = regs->u_regs[UREG_FP] + STACK_BIAS;
 383
 384         /* This is the X/Open sanctioned signal stack switching.  */
 385         if (ka->sa.sa_flags & SA_ONSTACK) {
 386                 if (!on_sig_stack(sp) &&
 387                     !((current->sas_ss_sp + current->sas_ss_size) & 7))
 388                         sp = current->sas_ss_sp + current->sas_ss_size;
 389         }
 390         return (void __user *)(sp - framesize);
 391 }
 392
 393 static inline void
 394 setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
 395                int signo, sigset_t *oldset, siginfo_t *info)
 396 {
 397         struct rt_signal_frame __user *sf;
 398         int sigframe_size, err;
 399
 400         /* 1. Make sure everything is clean */
 401         synchronize_user_stack();
 402         save_and_clear_fpu();
 403
 404         sigframe_size = RT_ALIGNEDSZ;
 405         if (!(current_thread_info()->fpsaved[0] & FPRS_FEF))
 406                 sigframe_size -= sizeof(__siginfo_fpu_t);
 407
 408         sf = (struct rt_signal_frame __user *)
 409                 get_sigframe(ka, regs, sigframe_size);
 410
 411         if (invalid_frame_pointer (sf, sigframe_size))
 412                 goto sigill;
 413
 414         if (get_thread_wsaved() != 0)
 415                 goto sigill;
 416
 417         /* 2. Save the current process state */
 418         err = copy_to_user(&sf->regs, regs, sizeof (*regs));
 419
 420         if (current_thread_info()->fpsaved[0] & FPRS_FEF) {
 421                 err |= save_fpu_state(regs, &sf->fpu_state);
 422                 err |= __put_user((u64)&sf->fpu_state, &sf->fpu_save);
 423         } else {
 424                 err |= __put_user(0, &sf->fpu_save);
 425         }
 426
 427         /* Setup sigaltstack */
 428         err |= __put_user(current->sas_ss_sp, &sf->stack.ss_sp);
 429         err |= __put_user(sas_ss_flags(regs->u_regs[UREG_FP]), &sf->stack.ss_flags);
 430         err |= __put_user(current->sas_ss_size, &sf->stack.ss_size);
 431
 432         err |= copy_to_user(&sf->mask, oldset, sizeof(sigset_t));
 433
 434         err |= copy_in_user((u64 __user *)sf,
 435                             (u64 __user *)(regs->u_regs[UREG_FP]+STACK_BIAS),
 436                             sizeof(struct reg_window));
 437
 438         if (info)
 439                 err |= copy_siginfo_to_user(&sf->info, info);
 440         else {
 441                 err |= __put_user(signo, &sf->info.si_signo);
 442                 err |= __put_user(SI_NOINFO, &sf->info.si_code);
 443         }
 444         if (err)
 445                 goto sigsegv;
 446
 447         /* 3. signal handler back-trampoline and parameters */
 448         regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;
 449         regs->u_regs[UREG_I0] = signo;
 450         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
 451
 452         /* The sigcontext is passed in this way because of how it
 453          * is defined in GLIBC's /usr/include/bits/sigcontext.h
 454          * for sparc64.  It includes the 128 bytes of siginfo_t.
 455          */
 456         regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
 457
 458         /* 5. signal handler */
 459         regs->tpc = (unsigned long) ka->sa.sa_handler;
 460         regs->tnpc = (regs->tpc + 4);
 461         if (test_thread_flag(TIF_32BIT)) {
 462                 regs->tpc &= 0xffffffff;
 463                 regs->tnpc &= 0xffffffff;
 464         }
 465         /* 4. return to kernel instructions */
 466         regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
 467         return;
 468
 469 sigill:
 470         do_exit(SIGILL);
 471 sigsegv:
 472         force_sigsegv(signo, current);
 473 }
 474
 475 static inline void handle_signal(unsigned long signr, struct k_sigaction *ka,
 476                                  siginfo_t *info,
 477                                  sigset_t *oldset, struct pt_regs *regs)
 478 {
 479         setup_rt_frame(ka, regs, signr, oldset,
 480                        (ka->sa.sa_flags & SA_SIGINFO) ? info : NULL);
 481         spin_lock_irq(&current->sighand->siglock);
 482         sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 483         if (!(ka->sa.sa_flags & SA_NOMASK))
 484                 sigaddset(&current->blocked,signr);
 485         recalc_sigpending();
 486         spin_unlock_irq(&current->sighand->siglock);
 487 }
 488
 489 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
 490                                      struct sigaction *sa)
 491 {
 492         switch (regs->u_regs[UREG_I0]) {
 493         case ERESTART_RESTARTBLOCK:
 494         case ERESTARTNOHAND:
 495         no_system_call_restart:
 496                 regs->u_regs[UREG_I0] = EINTR;
 497                 regs->tstate |= (TSTATE_ICARRY|TSTATE_XCARRY);
 498                 break;
 499         case ERESTARTSYS:
 500                 if (!(sa->sa_flags & SA_RESTART))
 501                         goto no_system_call_restart;
 502                 /* fallthrough */
 503         case ERESTARTNOINTR:
 504                 regs->u_regs[UREG_I0] = orig_i0;
 505                 regs->tpc -= 4;
 506                 regs->tnpc -= 4;
 507         }
 508 }
 509
 510 /* Note that 'init' is a special process: it doesn't get signals it doesn't
 511  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 512  * mistake.
 513  */
 514 static void do_signal(struct pt_regs *regs, unsigned long orig_i0, int restart_syscall)
 515 {
 516         siginfo_t info;
 517         struct signal_deliver_cookie cookie;
 518         struct k_sigaction ka;
 519         int signr;
 520         sigset_t *oldset;
 521
 522         cookie.restart_syscall = restart_syscall;
 523         cookie.orig_i0 = orig_i0;
 524
 525         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 526                 oldset = &current->saved_sigmask;
 527         else
 528                 oldset = &current->blocked;
 529
 530 #ifdef CONFIG_SPARC32_COMPAT
 531         if (test_thread_flag(TIF_32BIT)) {
 532                 extern void do_signal32(sigset_t *, struct pt_regs *,
 533                                         unsigned long, int);
 534                 do_signal32(oldset, regs, orig_i0,
 535                             cookie.restart_syscall);
 536                 return;
 537         }
 538 #endif
 539
 540         signr = get_signal_to_deliver(&info, &ka, regs, &cookie);
 541         if (signr > 0) {
 542                 if (cookie.restart_syscall)
 543                         syscall_restart(orig_i0, regs, &ka.sa);
 544                 handle_signal(signr, &ka, &info, oldset, regs);
 545
 546                 /* a signal was successfully delivered; the saved
 547                  * sigmask will have been stored in the signal frame,
 548                  * and will be restored by sigreturn, so we can simply
 549                  * clear the TIF_RESTORE_SIGMASK flag.
 550                  */
 551                 if (test_thread_flag(TIF_RESTORE_SIGMASK))
 552                         clear_thread_flag(TIF_RESTORE_SIGMASK);
 553                 return;
 554         }
 555         if (cookie.restart_syscall &&
 556             (regs->u_regs[UREG_I0] == ERESTARTNOHAND ||
 557              regs->u_regs[UREG_I0] == ERESTARTSYS ||
 558              regs->u_regs[UREG_I0] == ERESTARTNOINTR)) {
 559                 /* replay the system call when we are done */
 560                 regs->u_regs[UREG_I0] = cookie.orig_i0;
 561                 regs->tpc -= 4;
 562                 regs->tnpc -= 4;
 563         }
 564         if (cookie.restart_syscall &&
 565             regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
 566                 regs->u_regs[UREG_G1] = __NR_restart_syscall;
 567                 regs->tpc -= 4;
 568                 regs->tnpc -= 4;
 569         }
 570
 571         /* if there's no signal to deliver, we just put the saved sigmask
 572          * back
 573          */
 574         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 575                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 576                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 577         }
 578 }
 579
 580 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, int restart_syscall,
 581                       unsigned long thread_info_flags)
 582 {
 583         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
 584                 do_signal(regs, orig_i0, restart_syscall);
 585 }
 586
 587 void ptrace_signal_deliver(struct pt_regs *regs, void *cookie)
 588 {
 589         struct signal_deliver_cookie *cp = cookie;
 590
 591         if (cp->restart_syscall &&
 592             (regs->u_regs[UREG_I0] == ERESTARTNOHAND ||
 593              regs->u_regs[UREG_I0] == ERESTARTSYS ||
 594              regs->u_regs[UREG_I0] == ERESTARTNOINTR)) {
 595                 /* replay the system call when we are done */
 596                 regs->u_regs[UREG_I0] = cp->orig_i0;
 597                 regs->tpc -= 4;
 598                 regs->tnpc -= 4;
 599                 cp->restart_syscall = 0;
 600         }
 601         if (cp->restart_syscall &&
 602             regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
 603                 regs->u_regs[UREG_G1] = __NR_restart_syscall;
 604                 regs->tpc -= 4;
 605                 regs->tnpc -= 4;
 606                 cp->restart_syscall = 0;
 607         }
 608 }