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/uaccess.h>
  14 #include <linux/tracehook.h>
  15
  16 #include <asm/cacheflush.h>
  17 #include <asm/ucontext.h>
  18 #include <asm/fixed_code.h>
  19 #include <asm/syscall.h>
  20
  21 /* Location of the trace bit in SYSCFG. */
  22 #define TRACE_BITS 0x0001
  23
  24 struct fdpic_func_descriptor {
  25         unsigned long   text;
  26         unsigned long   GOT;
  27 };
  28
  29 struct rt_sigframe {
  30         int sig;
  31         struct siginfo *pinfo;
  32         void *puc;
  33         /* This is no longer needed by the kernel, but unfortunately userspace
  34          * code expects it to be there.  */
  35         char retcode[8];
  36         struct siginfo info;
  37         struct ucontext uc;
  38 };
  39
  40 asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
  41 {
  42         return do_sigaltstack(uss, uoss, rdusp());
  43 }
  44
  45 static inline int
  46 rt_restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *pr0)
  47 {
  48         unsigned long usp = 0;
  49         int err = 0;
  50
  51         /* Always make any pending restarted system calls return -EINTR */
  52         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  53
  54 #define RESTORE(x) err |= __get_user(regs->x, &sc->sc_##x)
  55
  56         /* restore passed registers */
  57         RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3);
  58         RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7);
  59         RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3);
  60         RESTORE(p4); RESTORE(p5);
  61         err |= __get_user(usp, &sc->sc_usp);
  62         wrusp(usp);
  63         RESTORE(a0w); RESTORE(a1w);
  64         RESTORE(a0x); RESTORE(a1x);
  65         RESTORE(astat);
  66         RESTORE(rets);
  67         RESTORE(pc);
  68         RESTORE(retx);
  69         RESTORE(fp);
  70         RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3);
  71         RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3);
  72         RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3);
  73         RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3);
  74         RESTORE(lc0); RESTORE(lc1);
  75         RESTORE(lt0); RESTORE(lt1);
  76         RESTORE(lb0); RESTORE(lb1);
  77         RESTORE(seqstat);
  78
  79         regs->orig_p0 = -1;     /* disable syscall checks */
  80
  81         *pr0 = regs->r0;
  82         return err;
  83 }
  84
  85 asmlinkage int sys_rt_sigreturn(void)
  86 {
  87         struct pt_regs *regs = current_pt_regs();
  88         unsigned long usp = rdusp();
  89         struct rt_sigframe *frame = (struct rt_sigframe *)(usp);
  90         sigset_t set;
  91         int r0;
  92
  93         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  94                 goto badframe;
  95         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
  96                 goto badframe;
  97
  98         set_current_blocked(&set);
  99
 100         if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
 101                 goto badframe;
 102
 103         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->usp) == -EFAULT)
 104                 goto badframe;
 105
 106         return r0;
 107
 108  badframe:
 109         force_sig(SIGSEGV, current);
 110         return 0;
 111 }
 112
 113 static inline int rt_setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs)
 114 {
 115         int err = 0;
 116
 117 #define SETUP(x) err |= __put_user(regs->x, &sc->sc_##x)
 118
 119         SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3);
 120         SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7);
 121         SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3);
 122         SETUP(p4); SETUP(p5);
 123         err |= __put_user(rdusp(), &sc->sc_usp);
 124         SETUP(a0w); SETUP(a1w);
 125         SETUP(a0x); SETUP(a1x);
 126         SETUP(astat);
 127         SETUP(rets);
 128         SETUP(pc);
 129         SETUP(retx);
 130         SETUP(fp);
 131         SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3);
 132         SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3);
 133         SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3);
 134         SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3);
 135         SETUP(lc0); SETUP(lc1);
 136         SETUP(lt0); SETUP(lt1);
 137         SETUP(lb0); SETUP(lb1);
 138         SETUP(seqstat);
 139
 140         return err;
 141 }
 142
 143 static inline void *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 144                                  size_t frame_size)
 145 {
 146         unsigned long usp;
 147
 148         /* Default to using normal stack.  */
 149         usp = rdusp();
 150
 151         /* This is the X/Open sanctioned signal stack switching.  */
 152         if (ka->sa.sa_flags & SA_ONSTACK) {
 153                 if (!on_sig_stack(usp))
 154                         usp = current->sas_ss_sp + current->sas_ss_size;
 155         }
 156         return (void *)((usp - frame_size) & -8UL);
 157 }
 158
 159 static int
 160 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info,
 161                sigset_t * set, struct pt_regs *regs)
 162 {
 163         struct rt_sigframe *frame;
 164         int err = 0;
 165
 166         frame = get_sigframe(ka, regs, sizeof(*frame));
 167
 168         err |= __put_user((current_thread_info()->exec_domain
 169                            && current_thread_info()->exec_domain->signal_invmap
 170                            && sig < 32
 171                            ? current_thread_info()->exec_domain->
 172                            signal_invmap[sig] : sig), &frame->sig);
 173
 174         err |= __put_user(&frame->info, &frame->pinfo);
 175         err |= __put_user(&frame->uc, &frame->puc);
 176         err |= copy_siginfo_to_user(&frame->info, info);
 177
 178         /* Create the ucontext.  */
 179         err |= __put_user(0, &frame->uc.uc_flags);
 180         err |= __put_user(0, &frame->uc.uc_link);
 181         err |=
 182             __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 183         err |= __put_user(sas_ss_flags(rdusp()), &frame->uc.uc_stack.ss_flags);
 184         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 185         err |= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
 186         err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 187
 188         if (err)
 189                 return -EFAULT;
 190
 191         /* Set up registers for signal handler */
 192         if (current->personality & FDPIC_FUNCPTRS) {
 193                 struct fdpic_func_descriptor __user *funcptr =
 194                         (struct fdpic_func_descriptor *) ka->sa.sa_handler;
 195                 u32 pc, p3;
 196                 err |= __get_user(pc, &funcptr->text);
 197                 err |= __get_user(p3, &funcptr->GOT);
 198                 if (err)
 199                         return -EFAULT;
 200                 regs->pc = pc;
 201                 regs->p3 = p3;
 202         } else
 203                 regs->pc = (unsigned long)ka->sa.sa_handler;
 204         wrusp((unsigned long)frame);
 205         regs->rets = SIGRETURN_STUB;
 206
 207         regs->r0 = frame->sig;
 208         regs->r1 = (unsigned long)(&frame->info);
 209         regs->r2 = (unsigned long)(&frame->uc);
 210
 211         return 0;
 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         /* are we from a system call? to see pt_regs->orig_p0 */
 252         if (regs->orig_p0 >= 0)
 253                 /* If so, check system call restarting.. */
 254                 handle_restart(regs, ka, 1);
 255
 256         /* set up the stack frame */
 257         if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs) < 0)
 258                 force_sigsegv(sig, current);
 259         else
 260                 signal_delivered(sig, info, ka, regs,
 261                                 test_thread_flag(TIF_SINGLESTEP));
 262 }
 263
 264 /*
 265  * Note that 'init' is a special process: it doesn't get signals it doesn't
 266  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 267  * mistake.
 268  *
 269  * Note that we go through the signals twice: once to check the signals
 270  * that the kernel can handle, and then we build all the user-level signal
 271  * handling stack-frames in one go after that.
 272  */
 273 asmlinkage void do_signal(struct pt_regs *regs)
 274 {
 275         siginfo_t info;
 276         int signr;
 277         struct k_sigaction ka;
 278
 279         current->thread.esp0 = (unsigned long)regs;
 280
 281         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 282         if (signr > 0) {
 283                 /* Whee!  Actually deliver the signal.  */
 284                 handle_signal(signr, &info, &ka, regs);
 285                 return;
 286         }
 287
 288         /* Did we come from a system call? */
 289         if (regs->orig_p0 >= 0)
 290                 /* Restart the system call - no handlers present */
 291                 handle_restart(regs, NULL, 0);
 292
 293         /* if there's no signal to deliver, we just put the saved sigmask
 294          * back */
 295         restore_saved_sigmask();
 296 }
 297
 298 /*
 299  * notification of userspace execution resumption
 300  */
 301 asmlinkage void do_notify_resume(struct pt_regs *regs)
 302 {
 303         if (test_thread_flag(TIF_SIGPENDING))
 304                 do_signal(regs);
 305
 306         if (test_thread_flag(TIF_NOTIFY_RESUME)) {
 307                 clear_thread_flag(TIF_NOTIFY_RESUME);
 308                 tracehook_notify_resume(regs);
 309         }
 310 }
 311