arch/mips/kernel/signal.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1991, 1992  Linus Torvalds
   7  * Copyright (C) 1994 - 2000  Ralf Baechle
   8  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   9  */
  10 #include <linux/config.h>
  11 #include <linux/sched.h>
  12 #include <linux/mm.h>
  13 #include <linux/personality.h>
  14 #include <linux/smp.h>
  15 #include <linux/smp_lock.h>
  16 #include <linux/kernel.h>
  17 #include <linux/signal.h>
  18 #include <linux/errno.h>
  19 #include <linux/wait.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/unistd.h>
  22 #include <linux/compiler.h>
  23
  24 #include <asm/asm.h>
  25 #include <linux/bitops.h>
  26 #include <asm/cacheflush.h>
  27 #include <asm/fpu.h>
  28 #include <asm/sim.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/ucontext.h>
  31 #include <asm/cpu-features.h>
  32
  33 #include "signal-common.h"
  34
  35 #define DEBUG_SIG 0
  36
  37 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  38
  39 static int do_signal(sigset_t *oldset, struct pt_regs *regs);
  40
  41 /*
  42  * Atomically swap in the new signal mask, and wait for a signal.
  43  */
  44
  45 #ifdef CONFIG_TRAD_SIGNALS
  46 save_static_function(sys_sigsuspend);
  47 __attribute_used__ noinline static int
  48 _sys_sigsuspend(nabi_no_regargs struct pt_regs regs)
  49 {
  50         sigset_t *uset, saveset, newset;
  51
  52         uset = (sigset_t *) regs.regs[4];
  53         if (copy_from_user(&newset, uset, sizeof(sigset_t)))
  54                 return -EFAULT;
  55         sigdelsetmask(&newset, ~_BLOCKABLE);
  56
  57         spin_lock_irq(&current->sighand->siglock);
  58         saveset = current->blocked;
  59         current->blocked = newset;
  60         recalc_sigpending();
  61         spin_unlock_irq(&current->sighand->siglock);
  62
  63         regs.regs[2] = EINTR;
  64         regs.regs[7] = 1;
  65         while (1) {
  66                 current->state = TASK_INTERRUPTIBLE;
  67                 schedule();
  68                 if (do_signal(&saveset, &regs))
  69                         return -EINTR;
  70         }
  71 }
  72 #endif
  73
  74 save_static_function(sys_rt_sigsuspend);
  75 __attribute_used__ noinline static int
  76 _sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
  77 {
  78         sigset_t *unewset, saveset, newset;
  79         size_t sigsetsize;
  80
  81         /* XXX Don't preclude handling different sized sigset_t's.  */
  82         sigsetsize = regs.regs[5];
  83         if (sigsetsize != sizeof(sigset_t))
  84                 return -EINVAL;
  85
  86         unewset = (sigset_t *) regs.regs[4];
  87         if (copy_from_user(&newset, unewset, sizeof(newset)))
  88                 return -EFAULT;
  89         sigdelsetmask(&newset, ~_BLOCKABLE);
  90
  91         spin_lock_irq(&current->sighand->siglock);
  92         saveset = current->blocked;
  93         current->blocked = newset;
  94         recalc_sigpending();
  95         spin_unlock_irq(&current->sighand->siglock);
  96
  97         regs.regs[2] = EINTR;
  98         regs.regs[7] = 1;
  99         while (1) {
 100                 current->state = TASK_INTERRUPTIBLE;
 101                 schedule();
 102                 if (do_signal(&saveset, &regs))
 103                         return -EINTR;
 104         }
 105 }
 106
 107 #ifdef CONFIG_TRAD_SIGNALS
 108 asmlinkage int sys_sigaction(int sig, const struct sigaction *act,
 109         struct sigaction *oact)
 110 {
 111         struct k_sigaction new_ka, old_ka;
 112         int ret;
 113         int err = 0;
 114
 115         if (act) {
 116                 old_sigset_t mask;
 117
 118                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 119                         return -EFAULT;
 120                 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
 121                 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 122                 err |= __get_user(mask, &act->sa_mask.sig[0]);
 123                 if (err)
 124                         return -EFAULT;
 125
 126                 siginitset(&new_ka.sa.sa_mask, mask);
 127         }
 128
 129         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 130
 131         if (!ret && oact) {
 132                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 133                         return -EFAULT;
 134                 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 135                 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
 136                 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
 137                 err |= __put_user(0, &oact->sa_mask.sig[1]);
 138                 err |= __put_user(0, &oact->sa_mask.sig[2]);
 139                 err |= __put_user(0, &oact->sa_mask.sig[3]);
 140                 if (err)
 141                         return -EFAULT;
 142         }
 143
 144         return ret;
 145 }
 146 #endif
 147
 148 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
 149 {
 150         const stack_t *uss = (const stack_t *) regs.regs[4];
 151         stack_t *uoss = (stack_t *) regs.regs[5];
 152         unsigned long usp = regs.regs[29];
 153
 154         return do_sigaltstack(uss, uoss, usp);
 155 }
 156
 157 #if PLAT_TRAMPOLINE_STUFF_LINE
 158 #define __tramp __attribute__((aligned(PLAT_TRAMPOLINE_STUFF_LINE)))
 159 #else
 160 #define __tramp
 161 #endif
 162
 163 #ifdef CONFIG_TRAD_SIGNALS
 164 struct sigframe {
 165         u32 sf_ass[4];                  /* argument save space for o32 */
 166         u32 sf_code[2] __tramp;         /* signal trampoline */
 167         struct sigcontext sf_sc __tramp;
 168         sigset_t sf_mask;
 169 };
 170 #endif
 171
 172 struct rt_sigframe {
 173         u32 rs_ass[4];                  /* argument save space for o32 */
 174         u32 rs_code[2] __tramp;         /* signal trampoline */
 175         struct siginfo rs_info __tramp;
 176         struct ucontext rs_uc;
 177 };
 178
 179 #ifdef CONFIG_TRAD_SIGNALS
 180 save_static_function(sys_sigreturn);
 181 __attribute_used__ noinline static void
 182 _sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 183 {
 184         struct sigframe *frame;
 185         sigset_t blocked;
 186
 187         frame = (struct sigframe *) regs.regs[29];
 188         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 189                 goto badframe;
 190         if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
 191                 goto badframe;
 192
 193         sigdelsetmask(&blocked, ~_BLOCKABLE);
 194         spin_lock_irq(&current->sighand->siglock);
 195         current->blocked = blocked;
 196         recalc_sigpending();
 197         spin_unlock_irq(&current->sighand->siglock);
 198
 199         if (restore_sigcontext(&regs, &frame->sf_sc))
 200                 goto badframe;
 201
 202         /*
 203          * Don't let your children do this ...
 204          */
 205         if (current_thread_info()->flags & TIF_SYSCALL_TRACE)
 206                 do_syscall_trace(&regs, 1);
 207         __asm__ __volatile__(
 208                 "move\t$29, %0\n\t"
 209                 "j\tsyscall_exit"
 210                 :/* no outputs */
 211                 :"r" (&regs));
 212         /* Unreached */
 213
 214 badframe:
 215         force_sig(SIGSEGV, current);
 216 }
 217 #endif
 218
 219 save_static_function(sys_rt_sigreturn);
 220 __attribute_used__ noinline static void
 221 _sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 222 {
 223         struct rt_sigframe *frame;
 224         sigset_t set;
 225         stack_t st;
 226
 227         frame = (struct rt_sigframe *) regs.regs[29];
 228         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 229                 goto badframe;
 230         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
 231                 goto badframe;
 232
 233         sigdelsetmask(&set, ~_BLOCKABLE);
 234         spin_lock_irq(&current->sighand->siglock);
 235         current->blocked = set;
 236         recalc_sigpending();
 237         spin_unlock_irq(&current->sighand->siglock);
 238
 239         if (restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext))
 240                 goto badframe;
 241
 242         if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
 243                 goto badframe;
 244         /* It is more difficult to avoid calling this function than to
 245            call it and ignore errors.  */
 246         do_sigaltstack(&st, NULL, regs.regs[29]);
 247
 248         /*
 249          * Don't let your children do this ...
 250          */
 251         __asm__ __volatile__(
 252                 "move\t$29, %0\n\t"
 253                 "j\tsyscall_exit"
 254                 :/* no outputs */
 255                 :"r" (&regs));
 256         /* Unreached */
 257
 258 badframe:
 259         force_sig(SIGSEGV, current);
 260 }
 261
 262 #ifdef CONFIG_TRAD_SIGNALS
 263 static void inline setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
 264         int signr, sigset_t *set)
 265 {
 266         struct sigframe *frame;
 267         int err = 0;
 268
 269         frame = get_sigframe(ka, regs, sizeof(*frame));
 270         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 271                 goto give_sigsegv;
 272
 273         /*
 274          * Set up the return code ...
 275          *
 276          *         li      v0, __NR_sigreturn
 277          *         syscall
 278          */
 279         if (PLAT_TRAMPOLINE_STUFF_LINE)
 280                 __clear_user(frame->sf_code, PLAT_TRAMPOLINE_STUFF_LINE);
 281         err |= __put_user(0x24020000 + __NR_sigreturn, frame->sf_code + 0);
 282         err |= __put_user(0x0000000c                 , frame->sf_code + 1);
 283         flush_cache_sigtramp((unsigned long) frame->sf_code);
 284
 285         err |= setup_sigcontext(regs, &frame->sf_sc);
 286         err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
 287         if (err)
 288                 goto give_sigsegv;
 289
 290         /*
 291          * Arguments to signal handler:
 292          *
 293          *   a0 = signal number
 294          *   a1 = 0 (should be cause)
 295          *   a2 = pointer to struct sigcontext
 296          *
 297          * $25 and c0_epc point to the signal handler, $29 points to the
 298          * struct sigframe.
 299          */
 300         regs->regs[ 4] = signr;
 301         regs->regs[ 5] = 0;
 302         regs->regs[ 6] = (unsigned long) &frame->sf_sc;
 303         regs->regs[29] = (unsigned long) frame;
 304         regs->regs[31] = (unsigned long) frame->sf_code;
 305         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 306
 307 #if DEBUG_SIG
 308         printk("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%p\n",
 309                current->comm, current->pid,
 310                frame, regs->cp0_epc, frame->regs[31]);
 311 #endif
 312         return;
 313
 314 give_sigsegv:
 315         force_sigsegv(signr, current);
 316 }
 317 #endif
 318
 319 static void inline setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
 320         int signr, sigset_t *set, siginfo_t *info)
 321 {
 322         struct rt_sigframe *frame;
 323         int err = 0;
 324
 325         frame = get_sigframe(ka, regs, sizeof(*frame));
 326         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 327                 goto give_sigsegv;
 328
 329         /*
 330          * Set up the return code ...
 331          *
 332          *         li      v0, __NR_rt_sigreturn
 333          *         syscall
 334          */
 335         if (PLAT_TRAMPOLINE_STUFF_LINE)
 336                 __clear_user(frame->rs_code, PLAT_TRAMPOLINE_STUFF_LINE);
 337         err |= __put_user(0x24020000 + __NR_rt_sigreturn, frame->rs_code + 0);
 338         err |= __put_user(0x0000000c                    , frame->rs_code + 1);
 339         flush_cache_sigtramp((unsigned long) frame->rs_code);
 340
 341         /* Create siginfo.  */
 342         err |= copy_siginfo_to_user(&frame->rs_info, info);
 343
 344         /* Create the ucontext.  */
 345         err |= __put_user(0, &frame->rs_uc.uc_flags);
 346         err |= __put_user(0, &frame->rs_uc.uc_link);
 347         err |= __put_user((void *)current->sas_ss_sp,
 348                           &frame->rs_uc.uc_stack.ss_sp);
 349         err |= __put_user(sas_ss_flags(regs->regs[29]),
 350                           &frame->rs_uc.uc_stack.ss_flags);
 351         err |= __put_user(current->sas_ss_size,
 352                           &frame->rs_uc.uc_stack.ss_size);
 353         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 354         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 355
 356         if (err)
 357                 goto give_sigsegv;
 358
 359         /*
 360          * Arguments to signal handler:
 361          *
 362          *   a0 = signal number
 363          *   a1 = 0 (should be cause)
 364          *   a2 = pointer to ucontext
 365          *
 366          * $25 and c0_epc point to the signal handler, $29 points to
 367          * the struct rt_sigframe.
 368          */
 369         regs->regs[ 4] = signr;
 370         regs->regs[ 5] = (unsigned long) &frame->rs_info;
 371         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 372         regs->regs[29] = (unsigned long) frame;
 373         regs->regs[31] = (unsigned long) frame->rs_code;
 374         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 375
 376 #if DEBUG_SIG
 377         printk("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%p\n",
 378                current->comm, current->pid,
 379                frame, regs->cp0_epc, regs->regs[31]);
 380 #endif
 381         return;
 382
 383 give_sigsegv:
 384         force_sigsegv(signr, current);
 385 }
 386
 387 extern void setup_rt_frame_n32(struct k_sigaction * ka,
 388         struct pt_regs *regs, int signr, sigset_t *set, siginfo_t *info);
 389
 390 static inline void handle_signal(unsigned long sig, siginfo_t *info,
 391         struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
 392 {
 393         switch(regs->regs[0]) {
 394         case ERESTART_RESTARTBLOCK:
 395         case ERESTARTNOHAND:
 396                 regs->regs[2] = EINTR;
 397                 break;
 398         case ERESTARTSYS:
 399                 if(!(ka->sa.sa_flags & SA_RESTART)) {
 400                         regs->regs[2] = EINTR;
 401                         break;
 402                 }
 403         /* fallthrough */
 404         case ERESTARTNOINTR:            /* Userland will reload $v0.  */
 405                 regs->regs[7] = regs->regs[26];
 406                 regs->cp0_epc -= 8;
 407         }
 408
 409         regs->regs[0] = 0;              /* Don't deal with this again.  */
 410
 411 #ifdef CONFIG_TRAD_SIGNALS
 412         if (ka->sa.sa_flags & SA_SIGINFO) {
 413 #else
 414         if (1) {
 415 #endif
 416 #ifdef CONFIG_MIPS32_N32
 417                 if ((current->thread.mflags & MF_ABI_MASK) == MF_N32)
 418                         setup_rt_frame_n32 (ka, regs, sig, oldset, info);
 419                 else
 420 #endif
 421                         setup_rt_frame(ka, regs, sig, oldset, info);
 422         }
 423 #ifdef CONFIG_TRAD_SIGNALS
 424         else
 425                 setup_frame(ka, regs, sig, oldset);
 426 #endif
 427
 428         if (!(ka->sa.sa_flags & SA_NODEFER)) {
 429                 spin_lock_irq(&current->sighand->siglock);
 430                 sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 431                 sigaddset(&current->blocked,sig);
 432                 recalc_sigpending();
 433                 spin_unlock_irq(&current->sighand->siglock);
 434         }
 435 }
 436
 437 extern int do_signal32(sigset_t *oldset, struct pt_regs *regs);
 438 extern int do_irix_signal(sigset_t *oldset, struct pt_regs *regs);
 439
 440 static int do_signal(sigset_t *oldset, struct pt_regs *regs)
 441 {
 442         struct k_sigaction ka;
 443         siginfo_t info;
 444         int signr;
 445
 446 #ifdef CONFIG_BINFMT_ELF32
 447         if ((current->thread.mflags & MF_ABI_MASK) == MF_O32) {
 448                 return do_signal32(oldset, regs);
 449         }
 450 #endif
 451
 452         /*
 453          * We want the common case to go fast, which is why we may in certain
 454          * cases get here from kernel mode. Just return without doing anything
 455          * if so.
 456          */
 457         if (!user_mode(regs))
 458                 return 1;
 459
 460         if (try_to_freeze(0))
 461                 goto no_signal;
 462
 463         if (!oldset)
 464                 oldset = &current->blocked;
 465
 466         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 467         if (signr > 0) {
 468                 handle_signal(signr, &info, &ka, oldset, regs);
 469                 return 1;
 470         }
 471
 472 no_signal:
 473         /*
 474          * Who's code doesn't conform to the restartable syscall convention
 475          * dies here!!!  The li instruction, a single machine instruction,
 476          * must directly be followed by the syscall instruction.
 477          */
 478         if (regs->regs[0]) {
 479                 if (regs->regs[2] == ERESTARTNOHAND ||
 480                     regs->regs[2] == ERESTARTSYS ||
 481                     regs->regs[2] == ERESTARTNOINTR) {
 482                         regs->regs[7] = regs->regs[26];
 483                         regs->cp0_epc -= 8;
 484                 }
 485                 if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
 486                         regs->regs[2] = __NR_restart_syscall;
 487                         regs->regs[7] = regs->regs[26];
 488                         regs->cp0_epc -= 4;
 489                 }
 490         }
 491         return 0;
 492 }
 493
 494 /*
 495  * notification of userspace execution resumption
 496  * - triggered by current->work.notify_resume
 497  */
 498 asmlinkage void do_notify_resume(struct pt_regs *regs, sigset_t *oldset,
 499         __u32 thread_info_flags)
 500 {
 501         /* deal with pending signal delivery */
 502         if (thread_info_flags & _TIF_SIGPENDING) {
 503 #ifdef CONFIG_BINFMT_ELF32
 504                 if (likely((current->thread.mflags & MF_ABI_MASK) == MF_O32)) {
 505                         do_signal32(oldset, regs);
 506                         return;
 507                 }
 508 #endif
 509 #ifdef CONFIG_BINFMT_IRIX
 510                 if (unlikely(current->personality != PER_LINUX)) {
 511                         do_irix_signal(oldset, regs);
 512                         return;
 513                 }
 514 #endif
 515                 do_signal(oldset, regs);
 516         }
 517 }