arch/blackfin/kernel/signal.c

   1 /*
   2  * Copyright 2004-2010 Analog Devices Inc.
   3  *
   4  * Licensed under the GPL-2 or later
   5  */
   6
   7 #include <linux/signal.h>
   8 #include <linux/syscalls.h>
   9 #include <linux/ptrace.h>
  10 #include <linux/tty.h>
  11 #include <linux/personality.h>
  12 #include <linux/binfmts.h>
  13 #include <linux/freezer.h>
  14 #include <linux/uaccess.h>
  15 #include <linux/tracehook.h>
  16
  17 #include <asm/cacheflush.h>
  18 #include <asm/ucontext.h>
  19 #include <asm/fixed_code.h>
  20 #include <asm/syscall.h>
  21
  22 /* Location of the trace bit in SYSCFG. */
  23 #define TRACE_BITS 0x0001
  24
  25 struct fdpic_func_descriptor {
  26         unsigned long   text;
  27         unsigned long   GOT;
  28 };
  29
  30 struct rt_sigframe {
  31         int sig;
  32         struct siginfo *pinfo;
  33         void *puc;
  34         /* This is no longer needed by the kernel, but unfortunately userspace
  35          * code expects it to be there.  */
  36         char retcode[8];
  37         struct siginfo info;
  38         struct ucontext uc;
  39 };
  40
  41 asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
  42 {
  43         return do_sigaltstack(uss, uoss, rdusp());
  44 }
  45
  46 static inline int
  47 rt_restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *pr0)
  48 {
  49         unsigned long usp = 0;
  50         int err = 0;
  51
  52         /* Always make any pending restarted system calls return -EINTR */
  53         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  54
  55 #define RESTORE(x) err |= __get_user(regs->x, &sc->sc_##x)
  56
  57         /* restore passed registers */
  58         RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3);
  59         RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7);
  60         RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3);
  61         RESTORE(p4); RESTORE(p5);
  62         err |= __get_user(usp, &sc->sc_usp);
  63         wrusp(usp);
  64         RESTORE(a0w); RESTORE(a1w);
  65         RESTORE(a0x); RESTORE(a1x);
  66         RESTORE(astat);
  67         RESTORE(rets);
  68         RESTORE(pc);
  69         RESTORE(retx);
  70         RESTORE(fp);
  71         RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3);
  72         RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3);
  73         RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3);
  74         RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3);
  75         RESTORE(lc0); RESTORE(lc1);
  76         RESTORE(lt0); RESTORE(lt1);
  77         RESTORE(lb0); RESTORE(lb1);
  78         RESTORE(seqstat);
  79
  80         regs->orig_p0 = -1;     /* disable syscall checks */
  81
  82         *pr0 = regs->r0;
  83         return err;
  84 }
  85
  86 asmlinkage int do_rt_sigreturn(unsigned long __unused)
  87 {
  88         struct pt_regs *regs = (struct pt_regs *)__unused;
  89         unsigned long usp = rdusp();
  90         struct rt_sigframe *frame = (struct rt_sigframe *)(usp);
  91         sigset_t set;
  92         int r0;
  93
  94         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  95                 goto badframe;
  96         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
  97                 goto badframe;
  98
  99         set_current_blocked(&set);
 100
 101         if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
 102                 goto badframe;
 103
 104         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->usp) == -EFAULT)
 105                 goto badframe;
 106
 107         return r0;
 108
 109  badframe:
 110         force_sig(SIGSEGV, current);
 111         return 0;
 112 }
 113
 114 static inline int rt_setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs)
 115 {
 116         int err = 0;
 117
 118 #define SETUP(x) err |= __put_user(regs->x, &sc->sc_##x)
 119
 120         SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3);
 121         SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7);
 122         SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3);
 123         SETUP(p4); SETUP(p5);
 124         err |= __put_user(rdusp(), &sc->sc_usp);
 125         SETUP(a0w); SETUP(a1w);
 126         SETUP(a0x); SETUP(a1x);
 127         SETUP(astat);
 128         SETUP(rets);
 129         SETUP(pc);
 130         SETUP(retx);
 131         SETUP(fp);
 132         SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3);
 133         SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3);
 134         SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3);
 135         SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3);
 136         SETUP(lc0); SETUP(lc1);
 137         SETUP(lt0); SETUP(lt1);
 138         SETUP(lb0); SETUP(lb1);
 139         SETUP(seqstat);
 140
 141         return err;
 142 }
 143
 144 static inline void *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 145                                  size_t frame_size)
 146 {
 147         unsigned long usp;
 148
 149         /* Default to using normal stack.  */
 150         usp = rdusp();
 151
 152         /* This is the X/Open sanctioned signal stack switching.  */
 153         if (ka->sa.sa_flags & SA_ONSTACK) {
 154                 if (!on_sig_stack(usp))
 155                         usp = current->sas_ss_sp + current->sas_ss_size;
 156         }
 157         return (void *)((usp - frame_size) & -8UL);
 158 }
 159
 160 static int
 161 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info,
 162                sigset_t * set, struct pt_regs *regs)
 163 {
 164         struct rt_sigframe *frame;
 165         int err = 0;
 166
 167         frame = get_sigframe(ka, regs, sizeof(*frame));
 168
 169         err |= __put_user((current_thread_info()->exec_domain
 170                            && current_thread_info()->exec_domain->signal_invmap
 171                            && sig < 32
 172                            ? current_thread_info()->exec_domain->
 173                            signal_invmap[sig] : sig), &frame->sig);
 174
 175         err |= __put_user(&frame->info, &frame->pinfo);
 176         err |= __put_user(&frame->uc, &frame->puc);
 177         err |= copy_siginfo_to_user(&frame->info, info);
 178
 179         /* Create the ucontext.  */
 180         err |= __put_user(0, &frame->uc.uc_flags);
 181         err |= __put_user(0, &frame->uc.uc_link);
 182         err |=
 183             __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 184         err |= __put_user(sas_ss_flags(rdusp()), &frame->uc.uc_stack.ss_flags);
 185         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 186         err |= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
 187         err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 188
 189         if (err)
 190                 goto give_sigsegv;
 191
 192         /* Set up registers for signal handler */
 193         wrusp((unsigned long)frame);
 194         if (current->personality & FDPIC_FUNCPTRS) {
 195                 struct fdpic_func_descriptor __user *funcptr =
 196                         (struct fdpic_func_descriptor *) ka->sa.sa_handler;
 197                 __get_user(regs->pc, &funcptr->text);
 198                 __get_user(regs->p3, &funcptr->GOT);
 199         } else
 200                 regs->pc = (unsigned long)ka->sa.sa_handler;
 201         regs->rets = SIGRETURN_STUB;
 202
 203         regs->r0 = frame->sig;
 204         regs->r1 = (unsigned long)(&frame->info);
 205         regs->r2 = (unsigned long)(&frame->uc);
 206
 207         return 0;
 208
 209  give_sigsegv:
 210         force_sigsegv(sig, current);
 211         return -EFAULT;
 212 }
 213
 214 static inline void
 215 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
 216 {
 217         switch (regs->r0) {
 218         case -ERESTARTNOHAND:
 219                 if (!has_handler)
 220                         goto do_restart;
 221                 regs->r0 = -EINTR;
 222                 break;
 223
 224         case -ERESTARTSYS:
 225                 if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
 226                         regs->r0 = -EINTR;
 227                         break;
 228                 }
 229                 /* fallthrough */
 230         case -ERESTARTNOINTR:
 231  do_restart:
 232                 regs->p0 = regs->orig_p0;
 233                 regs->r0 = regs->orig_r0;
 234                 regs->pc -= 2;
 235                 break;
 236
 237         case -ERESTART_RESTARTBLOCK:
 238                 regs->p0 = __NR_restart_syscall;
 239                 regs->pc -= 2;
 240                 break;
 241         }
 242 }
 243
 244 /*
 245  * OK, we're invoking a handler
 246  */
 247 static void
 248 handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
 249               struct pt_regs *regs)
 250 {
 251         int ret;
 252
 253         /* are we from a system call? to see pt_regs->orig_p0 */
 254         if (regs->orig_p0 >= 0)
 255                 /* If so, check system call restarting.. */
 256                 handle_restart(regs, ka, 1);
 257
 258         /* set up the stack frame */
 259         ret = setup_rt_frame(sig, ka, info, sigmask_to_save(), regs);
 260         if (ret)
 261                 return;
 262
 263         signal_delivered(sig, info, ka, regs,
 264                         test_thread_flag(TIF_SINGLESTEP));
 265 }
 266
 267 /*
 268  * Note that 'init' is a special process: it doesn't get signals it doesn't
 269  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 270  * mistake.
 271  *
 272  * Note that we go through the signals twice: once to check the signals
 273  * that the kernel can handle, and then we build all the user-level signal
 274  * handling stack-frames in one go after that.
 275  */
 276 asmlinkage void do_signal(struct pt_regs *regs)
 277 {
 278         siginfo_t info;
 279         int signr;
 280         struct k_sigaction ka;
 281
 282         current->thread.esp0 = (unsigned long)regs;
 283
 284         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 285         if (signr > 0) {
 286                 /* Whee!  Actually deliver the signal.  */
 287                 handle_signal(signr, &info, &ka, regs);
 288                 return;
 289         }
 290
 291         /* Did we come from a system call? */
 292         if (regs->orig_p0 >= 0)
 293                 /* Restart the system call - no handlers present */
 294                 handle_restart(regs, NULL, 0);
 295
 296         /* if there's no signal to deliver, we just put the saved sigmask
 297          * back */
 298         restore_saved_sigmask();
 299 }
 300
 301 /*
 302  * notification of userspace execution resumption
 303  */
 304 asmlinkage void do_notify_resume(struct pt_regs *regs)
 305 {
 306         if (test_thread_flag(TIF_SIGPENDING))
 307                 do_signal(regs);
 308
 309         if (test_thread_flag(TIF_NOTIFY_RESUME)) {
 310                 clear_thread_flag(TIF_NOTIFY_RESUME);
 311                 tracehook_notify_resume(regs);
 312         }
 313 }
 314