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