arch/sparc/kernel/signal_64.c

   1 /*
   2  *  arch/sparc64/kernel/signal.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *  Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
   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/tracehook.h>
  21 #include <linux/unistd.h>
  22 #include <linux/mm.h>
  23 #include <linux/tty.h>
  24 #include <linux/binfmts.h>
  25 #include <linux/bitops.h>
  26
  27 #include <asm/uaccess.h>
  28 #include <asm/ptrace.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 #include "sigutil.h"
  38
  39 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  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         mc_gregset_t __user *grp;
  47         unsigned long pc, npc, tstate;
  48         unsigned long fp, i7;
  49         unsigned char fenab;
  50         int err;
  51
  52         flush_user_windows();
  53         if (get_thread_wsaved()                                 ||
  54             (((unsigned long)ucp) & (sizeof(unsigned long)-1))  ||
  55             (!__access_ok(ucp, sizeof(*ucp))))
  56                 goto do_sigsegv;
  57         grp  = &ucp->uc_mcontext.mc_gregs;
  58         err  = __get_user(pc, &((*grp)[MC_PC]));
  59         err |= __get_user(npc, &((*grp)[MC_NPC]));
  60         if (err || ((pc | npc) & 3))
  61                 goto do_sigsegv;
  62         if (regs->u_regs[UREG_I1]) {
  63                 sigset_t set;
  64
  65                 if (_NSIG_WORDS == 1) {
  66                         if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0]))
  67                                 goto do_sigsegv;
  68                 } else {
  69                         if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t)))
  70                                 goto do_sigsegv;
  71                 }
  72                 sigdelsetmask(&set, ~_BLOCKABLE);
  73                 spin_lock_irq(&current->sighand->siglock);
  74                 current->blocked = set;
  75                 recalc_sigpending();
  76                 spin_unlock_irq(&current->sighand->siglock);
  77         }
  78         if (test_thread_flag(TIF_32BIT)) {
  79                 pc &= 0xffffffff;
  80                 npc &= 0xffffffff;
  81         }
  82         regs->tpc = pc;
  83         regs->tnpc = npc;
  84         err |= __get_user(regs->y, &((*grp)[MC_Y]));
  85         err |= __get_user(tstate, &((*grp)[MC_TSTATE]));
  86         regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
  87         regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
  88         err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1]));
  89         err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2]));
  90         err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3]));
  91         err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4]));
  92         err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5]));
  93         err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6]));
  94
  95         /* Skip %g7 as that's the thread register in userspace.  */
  96
  97         err |= __get_user(regs->u_regs[UREG_I0], (&(*grp)[MC_O0]));
  98         err |= __get_user(regs->u_regs[UREG_I1], (&(*grp)[MC_O1]));
  99         err |= __get_user(regs->u_regs[UREG_I2], (&(*grp)[MC_O2]));
 100         err |= __get_user(regs->u_regs[UREG_I3], (&(*grp)[MC_O3]));
 101         err |= __get_user(regs->u_regs[UREG_I4], (&(*grp)[MC_O4]));
 102         err |= __get_user(regs->u_regs[UREG_I5], (&(*grp)[MC_O5]));
 103         err |= __get_user(regs->u_regs[UREG_I6], (&(*grp)[MC_O6]));
 104         err |= __get_user(regs->u_regs[UREG_I7], (&(*grp)[MC_O7]));
 105
 106         err |= __get_user(fp, &(ucp->uc_mcontext.mc_fp));
 107         err |= __get_user(i7, &(ucp->uc_mcontext.mc_i7));
 108         err |= __put_user(fp,
 109               (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
 110         err |= __put_user(i7,
 111               (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
 112
 113         err |= __get_user(fenab, &(ucp->uc_mcontext.mc_fpregs.mcfpu_enab));
 114         if (fenab) {
 115                 unsigned long *fpregs = current_thread_info()->fpregs;
 116                 unsigned long fprs;
 117
 118                 fprs_write(0);
 119                 err |= __get_user(fprs, &(ucp->uc_mcontext.mc_fpregs.mcfpu_fprs));
 120                 if (fprs & FPRS_DL)
 121                         err |= copy_from_user(fpregs,
 122                                               &(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs),
 123                                               (sizeof(unsigned int) * 32));
 124                 if (fprs & FPRS_DU)
 125                         err |= copy_from_user(fpregs+16,
 126                          ((unsigned long __user *)&(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs))+16,
 127                          (sizeof(unsigned int) * 32));
 128                 err |= __get_user(current_thread_info()->xfsr[0],
 129                                   &(ucp->uc_mcontext.mc_fpregs.mcfpu_fsr));
 130                 err |= __get_user(current_thread_info()->gsr[0],
 131                                   &(ucp->uc_mcontext.mc_fpregs.mcfpu_gsr));
 132                 regs->tstate &= ~TSTATE_PEF;
 133         }
 134         if (err)
 135                 goto do_sigsegv;
 136
 137         return;
 138 do_sigsegv:
 139         force_sig(SIGSEGV, current);
 140 }
 141
 142 asmlinkage void sparc64_get_context(struct pt_regs *regs)
 143 {
 144         struct ucontext __user *ucp = (struct ucontext __user *)
 145                 regs->u_regs[UREG_I0];
 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
 228         return;
 229 do_sigsegv:
 230         force_sig(SIGSEGV, current);
 231 }
 232
 233 struct rt_signal_frame {
 234         struct sparc_stackf     ss;
 235         siginfo_t               info;
 236         struct pt_regs          regs;
 237         __siginfo_fpu_t __user  *fpu_save;
 238         stack_t                 stack;
 239         sigset_t                mask;
 240         __siginfo_rwin_t        *rwin_save;
 241 };
 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
 255         set_restore_sigmask();
 256
 257         return -ERESTARTNOHAND;
 258 }
 259
 260 asmlinkage long sys_sigpause(unsigned int set)
 261 {
 262         return _sigpause_common(set);
 263 }
 264
 265 asmlinkage long sys_sigsuspend(old_sigset_t set)
 266 {
 267         return _sigpause_common(set);
 268 }
 269
 270 void do_rt_sigreturn(struct pt_regs *regs)
 271 {
 272         struct rt_signal_frame __user *sf;
 273         unsigned long tpc, tnpc, tstate;
 274         __siginfo_fpu_t __user *fpu_save;
 275         __siginfo_rwin_t __user *rwin_save;
 276         sigset_t set;
 277         int err;
 278
 279         /* Always make any pending restarted system calls return -EINTR */
 280         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 281
 282         synchronize_user_stack ();
 283         sf = (struct rt_signal_frame __user *)
 284                 (regs->u_regs [UREG_FP] + STACK_BIAS);
 285
 286         /* 1. Make sure we are not getting garbage from the user */
 287         if (((unsigned long) sf) & 3)
 288                 goto segv;
 289
 290         err = get_user(tpc, &sf->regs.tpc);
 291         err |= __get_user(tnpc, &sf->regs.tnpc);
 292         if (test_thread_flag(TIF_32BIT)) {
 293                 tpc &= 0xffffffff;
 294                 tnpc &= 0xffffffff;
 295         }
 296         err |= ((tpc | tnpc) & 3);
 297
 298         /* 2. Restore the state */
 299         err |= __get_user(regs->y, &sf->regs.y);
 300         err |= __get_user(tstate, &sf->regs.tstate);
 301         err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs));
 302
 303         /* User can only change condition codes and %asi in %tstate. */
 304         regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
 305         regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
 306
 307         err |= __get_user(fpu_save, &sf->fpu_save);
 308         if (!err && fpu_save)
 309                 err |= restore_fpu_state(regs, fpu_save);
 310
 311         err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
 312         if (err || do_sigaltstack(&sf->stack, NULL, (unsigned long)sf) == -EFAULT)
 313                 goto segv;
 314
 315         err |= __get_user(rwin_save, &sf->rwin_save);
 316         if (!err && rwin_save) {
 317                 if (restore_rwin_state(rwin_save))
 318                         goto segv;
 319         }
 320
 321         regs->tpc = tpc;
 322         regs->tnpc = tnpc;
 323
 324         /* Prevent syscall restart.  */
 325         pt_regs_clear_syscall(regs);
 326
 327         sigdelsetmask(&set, ~_BLOCKABLE);
 328         spin_lock_irq(&current->sighand->siglock);
 329         current->blocked = set;
 330         recalc_sigpending();
 331         spin_unlock_irq(&current->sighand->siglock);
 332         return;
 333 segv:
 334         force_sig(SIGSEGV, current);
 335 }
 336
 337 /* Checks if the fp is valid */
 338 static int invalid_frame_pointer(void __user *fp)
 339 {
 340         if (((unsigned long) fp) & 15)
 341                 return 1;
 342         return 0;
 343 }
 344
 345 static inline void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, unsigned long framesize)
 346 {
 347         unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS;
 348
 349         /*
 350          * If we are on the alternate signal stack and would overflow it, don't.
 351          * Return an always-bogus address instead so we will die with SIGSEGV.
 352          */
 353         if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
 354                 return (void __user *) -1L;
 355
 356         /* This is the X/Open sanctioned signal stack switching.  */
 357         if (ka->sa.sa_flags & SA_ONSTACK) {
 358                 if (sas_ss_flags(sp) == 0)
 359                         sp = current->sas_ss_sp + current->sas_ss_size;
 360         }
 361
 362         sp -= framesize;
 363
 364         /* Always align the stack frame.  This handles two cases.  First,
 365          * sigaltstack need not be mindful of platform specific stack
 366          * alignment.  Second, if we took this signal because the stack
 367          * is not aligned properly, we'd like to take the signal cleanly
 368          * and report that.
 369          */
 370         sp &= ~15UL;
 371
 372         return (void __user *) sp;
 373 }
 374
 375 static inline int
 376 setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
 377                int signo, sigset_t *oldset, siginfo_t *info)
 378 {
 379         struct rt_signal_frame __user *sf;
 380         int wsaved, err, sf_size;
 381         void __user *tail;
 382
 383         /* 1. Make sure everything is clean */
 384         synchronize_user_stack();
 385         save_and_clear_fpu();
 386
 387         wsaved = get_thread_wsaved();
 388
 389         sf_size = sizeof(struct rt_signal_frame);
 390         if (current_thread_info()->fpsaved[0] & FPRS_FEF)
 391                 sf_size += sizeof(__siginfo_fpu_t);
 392         if (wsaved)
 393                 sf_size += sizeof(__siginfo_rwin_t);
 394         sf = (struct rt_signal_frame __user *)
 395                 get_sigframe(ka, regs, sf_size);
 396
 397         if (invalid_frame_pointer (sf))
 398                 goto sigill;
 399
 400         tail = (sf + 1);
 401
 402         /* 2. Save the current process state */
 403         err = copy_to_user(&sf->regs, regs, sizeof (*regs));
 404
 405         if (current_thread_info()->fpsaved[0] & FPRS_FEF) {
 406                 __siginfo_fpu_t __user *fpu_save = tail;
 407                 tail += sizeof(__siginfo_fpu_t);
 408                 err |= save_fpu_state(regs, fpu_save);
 409                 err |= __put_user((u64)fpu_save, &sf->fpu_save);
 410         } else {
 411                 err |= __put_user(0, &sf->fpu_save);
 412         }
 413         if (wsaved) {
 414                 __siginfo_rwin_t __user *rwin_save = tail;
 415                 tail += sizeof(__siginfo_rwin_t);
 416                 err |= save_rwin_state(wsaved, rwin_save);
 417                 err |= __put_user((u64)rwin_save, &sf->rwin_save);
 418                 set_thread_wsaved(0);
 419         } else {
 420                 err |= __put_user(0, &sf->rwin_save);
 421         }
 422
 423         /* Setup sigaltstack */
 424         err |= __put_user(current->sas_ss_sp, &sf->stack.ss_sp);
 425         err |= __put_user(sas_ss_flags(regs->u_regs[UREG_FP]), &sf->stack.ss_flags);
 426         err |= __put_user(current->sas_ss_size, &sf->stack.ss_size);
 427
 428         err |= copy_to_user(&sf->mask, oldset, sizeof(sigset_t));
 429
 430         if (!wsaved) {
 431                 err |= copy_in_user((u64 __user *)sf,
 432                                     (u64 __user *)(regs->u_regs[UREG_FP] +
 433                                                    STACK_BIAS),
 434                                     sizeof(struct reg_window));
 435         } else {
 436                 struct reg_window *rp;
 437
 438                 rp = &current_thread_info()->reg_window[wsaved - 1];
 439                 err |= copy_to_user(sf, rp, sizeof(struct reg_window));
 440         }
 441         if (info)
 442                 err |= copy_siginfo_to_user(&sf->info, info);
 443         else {
 444                 err |= __put_user(signo, &sf->info.si_signo);
 445                 err |= __put_user(SI_NOINFO, &sf->info.si_code);
 446         }
 447         if (err)
 448                 goto sigsegv;
 449
 450         /* 3. signal handler back-trampoline and parameters */
 451         regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;
 452         regs->u_regs[UREG_I0] = signo;
 453         regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
 454
 455         /* The sigcontext is passed in this way because of how it
 456          * is defined in GLIBC's /usr/include/bits/sigcontext.h
 457          * for sparc64.  It includes the 128 bytes of siginfo_t.
 458          */
 459         regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
 460
 461         /* 5. signal handler */
 462         regs->tpc = (unsigned long) ka->sa.sa_handler;
 463         regs->tnpc = (regs->tpc + 4);
 464         if (test_thread_flag(TIF_32BIT)) {
 465                 regs->tpc &= 0xffffffff;
 466                 regs->tnpc &= 0xffffffff;
 467         }
 468         /* 4. return to kernel instructions */
 469         regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
 470         return 0;
 471
 472 sigill:
 473         do_exit(SIGILL);
 474         return -EINVAL;
 475
 476 sigsegv:
 477         force_sigsegv(signo, current);
 478         return -EFAULT;
 479 }
 480
 481 static inline int handle_signal(unsigned long signr, struct k_sigaction *ka,
 482                                 siginfo_t *info,
 483                                 sigset_t *oldset, struct pt_regs *regs)
 484 {
 485         int err;
 486
 487         err = setup_rt_frame(ka, regs, signr, oldset,
 488                              (ka->sa.sa_flags & SA_SIGINFO) ? info : NULL);
 489         if (err)
 490                 return err;
 491         spin_lock_irq(&current->sighand->siglock);
 492         sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 493         if (!(ka->sa.sa_flags & SA_NOMASK))
 494                 sigaddset(&current->blocked,signr);
 495         recalc_sigpending();
 496         spin_unlock_irq(&current->sighand->siglock);
 497
 498         tracehook_signal_handler(signr, info, ka, regs, 0);
 499
 500         return 0;
 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         /* It's a lot of work and synchronization to add a new ptrace
 537          * register for GDB to save and restore in order to get
 538          * orig_i0 correct for syscall restarts when debugging.
 539          *
 540          * Although it should be the case that most of the global
 541          * registers are volatile across a system call, glibc already
 542          * depends upon that fact that we preserve them.  So we can't
 543          * just use any global register to save away the orig_i0 value.
 544          *
 545          * In particular %g2, %g3, %g4, and %g5 are all assumed to be
 546          * preserved across a system call trap by various pieces of
 547          * code in glibc.
 548          *
 549          * %g7 is used as the "thread register".   %g6 is not used in
 550          * any fixed manner.  %g6 is used as a scratch register and
 551          * a compiler temporary, but it's value is never used across
 552          * a system call.  Therefore %g6 is usable for orig_i0 storage.
 553          */
 554         if (pt_regs_is_syscall(regs) &&
 555             (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY)))
 556                 regs->u_regs[UREG_G6] = orig_i0;
 557
 558         if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 559                 oldset = &current->saved_sigmask;
 560         else
 561                 oldset = &current->blocked;
 562
 563 #ifdef CONFIG_COMPAT
 564         if (test_thread_flag(TIF_32BIT)) {
 565                 extern void do_signal32(sigset_t *, struct pt_regs *);
 566                 do_signal32(oldset, regs);
 567                 return;
 568         }
 569 #endif
 570
 571         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 572
 573         restart_syscall = 0;
 574         if (pt_regs_is_syscall(regs) &&
 575             (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) {
 576                 restart_syscall = 1;
 577                 orig_i0 = regs->u_regs[UREG_G6];
 578         }
 579
 580         if (signr > 0) {
 581                 if (restart_syscall)
 582                         syscall_restart(orig_i0, regs, &ka.sa);
 583                 if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
 584                         /* A signal was successfully delivered; the saved
 585                          * sigmask will have been stored in the signal frame,
 586                          * and will be restored by sigreturn, so we can simply
 587                          * clear the TS_RESTORE_SIGMASK flag.
 588                          */
 589                         current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 590                 }
 591                 return;
 592         }
 593         if (restart_syscall &&
 594             (regs->u_regs[UREG_I0] == ERESTARTNOHAND ||
 595              regs->u_regs[UREG_I0] == ERESTARTSYS ||
 596              regs->u_regs[UREG_I0] == ERESTARTNOINTR)) {
 597                 /* replay the system call when we are done */
 598                 regs->u_regs[UREG_I0] = orig_i0;
 599                 regs->tpc -= 4;
 600                 regs->tnpc -= 4;
 601                 pt_regs_clear_syscall(regs);
 602         }
 603         if (restart_syscall &&
 604             regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
 605                 regs->u_regs[UREG_G1] = __NR_restart_syscall;
 606                 regs->tpc -= 4;
 607                 regs->tnpc -= 4;
 608                 pt_regs_clear_syscall(regs);
 609         }
 610
 611         /* If there's no signal to deliver, we just put the saved sigmask
 612          * back
 613          */
 614         if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 615                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 616                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 617         }
 618 }
 619
 620 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags)
 621 {
 622         if (thread_info_flags & _TIF_SIGPENDING)
 623                 do_signal(regs, orig_i0);
 624         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 625                 clear_thread_flag(TIF_NOTIFY_RESUME);
 626                 tracehook_notify_resume(regs);
 627                 if (current->replacement_session_keyring)
 628                         key_replace_session_keyring();
 629         }
 630 }
 631