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