arch/m32r/kernel/signal.c

   1 /*
   2  *  linux/arch/m32r/kernel/signal.c
   3  *
   4  *  Copyright (c) 2003  Hitoshi Yamamoto
   5  *
   6  *  Taken from i386 version.
   7  *  Copyright (C) 1991, 1992  Linus Torvalds
   8  *
   9  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
  10  *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
  11  */
  12
  13 #include <linux/sched.h>
  14 #include <linux/mm.h>
  15 #include <linux/smp.h>
  16 #include <linux/kernel.h>
  17 #include <linux/signal.h>
  18 #include <linux/errno.h>
  19 #include <linux/wait.h>
  20 #include <linux/unistd.h>
  21 #include <linux/stddef.h>
  22 #include <linux/personality.h>
  23 #include <linux/freezer.h>
  24 #include <linux/tracehook.h>
  25 #include <asm/cacheflush.h>
  26 #include <asm/ucontext.h>
  27 #include <asm/uaccess.h>
  28
  29 #define DEBUG_SIG 0
  30
  31 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  32
  33 asmlinkage int
  34 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
  35                 unsigned long r2, unsigned long r3, unsigned long r4,
  36                 unsigned long r5, unsigned long r6, struct pt_regs *regs)
  37 {
  38         return do_sigaltstack(uss, uoss, regs->spu);
  39 }
  40
  41
  42 /*
  43  * Do a signal return; undo the signal stack.
  44  */
  45
  46 struct rt_sigframe
  47 {
  48         int sig;
  49         struct siginfo __user *pinfo;
  50         void __user *puc;
  51         struct siginfo info;
  52         struct ucontext uc;
  53 //      struct _fpstate fpstate;
  54 };
  55
  56 static int
  57 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
  58                    int *r0_p)
  59 {
  60         unsigned int err = 0;
  61
  62         /* Always make any pending restarted system calls return -EINTR */
  63         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  64
  65 #define COPY(x)         err |= __get_user(regs->x, &sc->sc_##x)
  66         COPY(r4);
  67         COPY(r5);
  68         COPY(r6);
  69         COPY(pt_regs);
  70         /* COPY(r0); Skip r0 */
  71         COPY(r1);
  72         COPY(r2);
  73         COPY(r3);
  74         COPY(r7);
  75         COPY(r8);
  76         COPY(r9);
  77         COPY(r10);
  78         COPY(r11);
  79         COPY(r12);
  80         COPY(acc0h);
  81         COPY(acc0l);
  82         COPY(acc1h);            /* ISA_DSP_LEVEL2 only */
  83         COPY(acc1l);            /* ISA_DSP_LEVEL2 only */
  84         COPY(psw);
  85         COPY(bpc);
  86         COPY(bbpsw);
  87         COPY(bbpc);
  88         COPY(spu);
  89         COPY(fp);
  90         COPY(lr);
  91         COPY(spi);
  92 #undef COPY
  93
  94         regs->syscall_nr = -1;  /* disable syscall checks */
  95         err |= __get_user(*r0_p, &sc->sc_r0);
  96
  97         return err;
  98 }
  99
 100 asmlinkage int
 101 sys_rt_sigreturn(unsigned long r0, unsigned long r1,
 102                  unsigned long r2, unsigned long r3, unsigned long r4,
 103                  unsigned long r5, unsigned long r6, struct pt_regs *regs)
 104 {
 105         struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->spu;
 106         sigset_t set;
 107         int result;
 108
 109         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 110                 goto badframe;
 111         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 112                 goto badframe;
 113
 114         sigdelsetmask(&set, ~_BLOCKABLE);
 115         set_current_blocked(&set);
 116
 117         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &result))
 118                 goto badframe;
 119
 120         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->spu) == -EFAULT)
 121                 goto badframe;
 122
 123         return result;
 124
 125 badframe:
 126         force_sig(SIGSEGV, current);
 127         return 0;
 128 }
 129
 130 /*
 131  * Set up a signal frame.
 132  */
 133
 134 static int
 135 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 136                  unsigned long mask)
 137 {
 138         int err = 0;
 139
 140 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
 141         COPY(r4);
 142         COPY(r5);
 143         COPY(r6);
 144         COPY(pt_regs);
 145         COPY(r0);
 146         COPY(r1);
 147         COPY(r2);
 148         COPY(r3);
 149         COPY(r7);
 150         COPY(r8);
 151         COPY(r9);
 152         COPY(r10);
 153         COPY(r11);
 154         COPY(r12);
 155         COPY(acc0h);
 156         COPY(acc0l);
 157         COPY(acc1h);            /* ISA_DSP_LEVEL2 only */
 158         COPY(acc1l);            /* ISA_DSP_LEVEL2 only */
 159         COPY(psw);
 160         COPY(bpc);
 161         COPY(bbpsw);
 162         COPY(bbpc);
 163         COPY(spu);
 164         COPY(fp);
 165         COPY(lr);
 166         COPY(spi);
 167 #undef COPY
 168
 169         err |= __put_user(mask, &sc->oldmask);
 170
 171         return err;
 172 }
 173
 174 /*
 175  * Determine which stack to use..
 176  */
 177 static inline void __user *
 178 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
 179 {
 180         /* This is the X/Open sanctioned signal stack switching.  */
 181         if (ka->sa.sa_flags & SA_ONSTACK) {
 182                 if (sas_ss_flags(sp) == 0)
 183                         sp = current->sas_ss_sp + current->sas_ss_size;
 184         }
 185
 186         return (void __user *)((sp - frame_size) & -8ul);
 187 }
 188
 189 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 190                            sigset_t *set, struct pt_regs *regs)
 191 {
 192         struct rt_sigframe __user *frame;
 193         int err = 0;
 194         int signal;
 195
 196         frame = get_sigframe(ka, regs->spu, sizeof(*frame));
 197
 198         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 199                 goto give_sigsegv;
 200
 201         signal = current_thread_info()->exec_domain
 202                 && current_thread_info()->exec_domain->signal_invmap
 203                 && sig < 32
 204                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 205                 : sig;
 206
 207         err |= __put_user(signal, &frame->sig);
 208         if (err)
 209                 goto give_sigsegv;
 210
 211         err |= __put_user(&frame->info, &frame->pinfo);
 212         err |= __put_user(&frame->uc, &frame->puc);
 213         err |= copy_siginfo_to_user(&frame->info, info);
 214         if (err)
 215                 goto give_sigsegv;
 216
 217         /* Create the ucontext.  */
 218         err |= __put_user(0, &frame->uc.uc_flags);
 219         err |= __put_user(0, &frame->uc.uc_link);
 220         err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 221         err |= __put_user(sas_ss_flags(regs->spu),
 222                           &frame->uc.uc_stack.ss_flags);
 223         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 224         err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
 225         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 226         if (err)
 227                 goto give_sigsegv;
 228
 229         /* Set up to return from userspace.  */
 230         regs->lr = (unsigned long)ka->sa.sa_restorer;
 231
 232         /* Set up registers for signal handler */
 233         regs->spu = (unsigned long)frame;
 234         regs->r0 = signal;      /* Arg for signal handler */
 235         regs->r1 = (unsigned long)&frame->info;
 236         regs->r2 = (unsigned long)&frame->uc;
 237         regs->bpc = (unsigned long)ka->sa.sa_handler;
 238
 239         set_fs(USER_DS);
 240
 241 #if DEBUG_SIG
 242         printk("SIG deliver (%s:%d): sp=%p pc=%p\n",
 243                 current->comm, current->pid, frame, regs->pc);
 244 #endif
 245
 246         return 0;
 247
 248 give_sigsegv:
 249         force_sigsegv(sig, current);
 250         return -EFAULT;
 251 }
 252
 253 static int prev_insn(struct pt_regs *regs)
 254 {
 255         u16 inst;
 256         if (get_user(inst, (u16 __user *)(regs->bpc - 2)))
 257                 return -EFAULT;
 258         if ((inst & 0xfff0) == 0x10f0)  /* trap ? */
 259                 regs->bpc -= 2;
 260         else
 261                 regs->bpc -= 4;
 262         regs->syscall_nr = -1;
 263         return 0;
 264 }
 265
 266 /*
 267  * OK, we're invoking a handler
 268  */
 269
 270 static int
 271 handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
 272               sigset_t *oldset, struct pt_regs *regs)
 273 {
 274         /* Are we from a system call? */
 275         if (regs->syscall_nr >= 0) {
 276                 /* If so, check system call restarting.. */
 277                 switch (regs->r0) {
 278                         case -ERESTART_RESTARTBLOCK:
 279                         case -ERESTARTNOHAND:
 280                                 regs->r0 = -EINTR;
 281                                 break;
 282
 283                         case -ERESTARTSYS:
 284                                 if (!(ka->sa.sa_flags & SA_RESTART)) {
 285                                         regs->r0 = -EINTR;
 286                                         break;
 287                                 }
 288                         /* fallthrough */
 289                         case -ERESTARTNOINTR:
 290                                 regs->r0 = regs->orig_r0;
 291                                 if (prev_insn(regs) < 0)
 292                                         return -EFAULT;
 293                 }
 294         }
 295
 296         /* Set up the stack frame */
 297         if (setup_rt_frame(sig, ka, info, oldset, regs))
 298                 return -EFAULT;
 299
 300         block_sigmask(ka, sig);
 301         return 0;
 302 }
 303
 304 /*
 305  * Note that 'init' is a special process: it doesn't get signals it doesn't
 306  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 307  * mistake.
 308  */
 309 static void do_signal(struct pt_regs *regs)
 310 {
 311         siginfo_t info;
 312         int signr;
 313         struct k_sigaction ka;
 314         sigset_t *oldset;
 315
 316         /*
 317          * We want the common case to go fast, which
 318          * is why we may in certain cases get here from
 319          * kernel mode. Just return without doing anything
 320          * if so.
 321          */
 322         if (!user_mode(regs))
 323                 return;
 324
 325         if (try_to_freeze())
 326                 goto no_signal;
 327
 328         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 329                 oldset = &current->saved_sigmask;
 330         else
 331                 oldset = &current->blocked;
 332
 333         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 334         if (signr > 0) {
 335                 /* Re-enable any watchpoints before delivering the
 336                  * signal to user space. The processor register will
 337                  * have been cleared if the watchpoint triggered
 338                  * inside the kernel.
 339                  */
 340
 341                 /* Whee!  Actually deliver the signal.  */
 342                 if (handle_signal(signr, &ka, &info, oldset, regs) == 0)
 343                         clear_thread_flag(TIF_RESTORE_SIGMASK);
 344
 345                 return;
 346         }
 347
 348  no_signal:
 349         /* Did we come from a system call? */
 350         if (regs->syscall_nr >= 0) {
 351                 /* Restart the system call - no handlers present */
 352                 if (regs->r0 == -ERESTARTNOHAND ||
 353                     regs->r0 == -ERESTARTSYS ||
 354                     regs->r0 == -ERESTARTNOINTR) {
 355                         regs->r0 = regs->orig_r0;
 356                         prev_insn(regs);
 357                 } else if (regs->r0 == -ERESTART_RESTARTBLOCK){
 358                         regs->r0 = regs->orig_r0;
 359                         regs->r7 = __NR_restart_syscall;
 360                         prev_insn(regs);
 361                 }
 362         }
 363         restore_saved_sigmask();
 364 }
 365
 366 /*
 367  * notification of userspace execution resumption
 368  * - triggered by current->work.notify_resume
 369  */
 370 void do_notify_resume(struct pt_regs *regs, __u32 thread_info_flags)
 371 {
 372         /* Pending single-step? */
 373         if (thread_info_flags & _TIF_SINGLESTEP)
 374                 clear_thread_flag(TIF_SINGLESTEP);
 375
 376         /* deal with pending signal delivery */
 377         if (thread_info_flags & _TIF_SIGPENDING)
 378                 do_signal(regs);
 379
 380         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 381                 clear_thread_flag(TIF_NOTIFY_RESUME);
 382                 tracehook_notify_resume(regs);
 383         }
 384
 385         clear_thread_flag(TIF_IRET);
 386 }