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