arch/blackfin/kernel/signal.c

   1 /*
   2  * File:         arch/blackfin/kernel/signal.c
   3  * Based on:
   4  * Author:
   5  *
   6  * Created:
   7  * Description:
   8  *
   9  * Modified:
  10  *               Copyright 2004-2006 Analog Devices Inc.
  11  *
  12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, see the file COPYING, or write
  26  * to the Free Software Foundation, Inc.,
  27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  28  */
  29
  30 #include <linux/signal.h>
  31 #include <linux/syscalls.h>
  32 #include <linux/ptrace.h>
  33 #include <linux/tty.h>
  34 #include <linux/personality.h>
  35 #include <linux/binfmts.h>
  36 #include <linux/freezer.h>
  37
  38 #include <asm/uaccess.h>
  39 #include <asm/cacheflush.h>
  40 #include <asm/ucontext.h>
  41
  42 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  43
  44 struct fdpic_func_descriptor {
  45         unsigned long   text;
  46         unsigned long   GOT;
  47 };
  48
  49 struct rt_sigframe {
  50         int sig;
  51         struct siginfo *pinfo;
  52         void *puc;
  53         char retcode[8];
  54         struct siginfo info;
  55         struct ucontext uc;
  56 };
  57
  58 asmlinkage int sys_sigaltstack(const stack_t * uss, stack_t * uoss)
  59 {
  60         return do_sigaltstack(uss, uoss, rdusp());
  61 }
  62
  63 static inline int
  64 rt_restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *pr0)
  65 {
  66         unsigned long usp = 0;
  67         int err = 0;
  68
  69 #define RESTORE(x) err |= __get_user(regs->x, &sc->sc_##x)
  70
  71         /* restore passed registers */
  72         RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3);
  73         RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7);
  74         RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3);
  75         RESTORE(p4); RESTORE(p5);
  76         err |= __get_user(usp, &sc->sc_usp);
  77         wrusp(usp);
  78         RESTORE(a0w); RESTORE(a1w);
  79         RESTORE(a0x); RESTORE(a1x);
  80         RESTORE(astat);
  81         RESTORE(rets);
  82         RESTORE(pc);
  83         RESTORE(retx);
  84         RESTORE(fp);
  85         RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3);
  86         RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3);
  87         RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3);
  88         RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3);
  89         RESTORE(lc0); RESTORE(lc1);
  90         RESTORE(lt0); RESTORE(lt1);
  91         RESTORE(lb0); RESTORE(lb1);
  92         RESTORE(seqstat);
  93
  94         regs->orig_p0 = -1;     /* disable syscall checks */
  95
  96         *pr0 = regs->r0;
  97         return err;
  98 }
  99
 100 asmlinkage int do_rt_sigreturn(unsigned long __unused)
 101 {
 102         struct pt_regs *regs = (struct pt_regs *)__unused;
 103         unsigned long usp = rdusp();
 104         struct rt_sigframe *frame = (struct rt_sigframe *)(usp);
 105         sigset_t set;
 106         int r0;
 107
 108         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 109                 goto badframe;
 110         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 111                 goto badframe;
 112
 113         sigdelsetmask(&set, ~_BLOCKABLE);
 114         spin_lock_irq(&current->sighand->siglock);
 115         current->blocked = set;
 116         recalc_sigpending();
 117         spin_unlock_irq(&current->sighand->siglock);
 118
 119         if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
 120                 goto badframe;
 121
 122         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->usp) == -EFAULT)
 123                 goto badframe;
 124
 125         return r0;
 126
 127       badframe:
 128         force_sig(SIGSEGV, current);
 129         return 0;
 130 }
 131
 132 static inline int rt_setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs)
 133 {
 134         int err = 0;
 135
 136 #define SETUP(x) err |= __put_user(regs->x, &sc->sc_##x)
 137
 138         SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3);
 139         SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7);
 140         SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3);
 141         SETUP(p4); SETUP(p5);
 142         err |= __put_user(rdusp(), &sc->sc_usp);
 143         SETUP(a0w); SETUP(a1w);
 144         SETUP(a0x); SETUP(a1x);
 145         SETUP(astat);
 146         SETUP(rets);
 147         SETUP(pc);
 148         SETUP(retx);
 149         SETUP(fp);
 150         SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3);
 151         SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3);
 152         SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3);
 153         SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3);
 154         SETUP(lc0); SETUP(lc1);
 155         SETUP(lt0); SETUP(lt1);
 156         SETUP(lb0); SETUP(lb1);
 157         SETUP(seqstat);
 158
 159         return err;
 160 }
 161
 162 static inline void push_cache(unsigned long vaddr, unsigned int len)
 163 {
 164         flush_icache_range(vaddr, vaddr + len);
 165 }
 166
 167 static inline void *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 168                                  size_t frame_size)
 169 {
 170         unsigned long usp;
 171
 172         /* Default to using normal stack.  */
 173         usp = rdusp();
 174
 175         /* This is the X/Open sanctioned signal stack switching.  */
 176         if (ka->sa.sa_flags & SA_ONSTACK) {
 177                 if (!on_sig_stack(usp))
 178                         usp = current->sas_ss_sp + current->sas_ss_size;
 179         }
 180         return (void *)((usp - frame_size) & -8UL);
 181 }
 182
 183 static int
 184 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info,
 185                sigset_t * set, struct pt_regs *regs)
 186 {
 187         struct rt_sigframe *frame;
 188         int err = 0;
 189
 190         frame = get_sigframe(ka, regs, sizeof(*frame));
 191
 192         err |= __put_user((current_thread_info()->exec_domain
 193                            && current_thread_info()->exec_domain->signal_invmap
 194                            && sig < 32
 195                            ? current_thread_info()->exec_domain->
 196                            signal_invmap[sig] : sig), &frame->sig);
 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
 202         /* Create the ucontext.  */
 203         err |= __put_user(0, &frame->uc.uc_flags);
 204         err |= __put_user(0, &frame->uc.uc_link);
 205         err |=
 206             __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 207         err |= __put_user(sas_ss_flags(rdusp()), &frame->uc.uc_stack.ss_flags);
 208         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 209         err |= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
 210         err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 211
 212         /* Set up to return from userspace.  */
 213         err |= __put_user(0x28, &(frame->retcode[0]));
 214         err |= __put_user(0xe1, &(frame->retcode[1]));
 215         err |= __put_user(0xad, &(frame->retcode[2]));
 216         err |= __put_user(0x00, &(frame->retcode[3]));
 217         err |= __put_user(0xa0, &(frame->retcode[4]));
 218         err |= __put_user(0x00, &(frame->retcode[5]));
 219
 220         if (err)
 221                 goto give_sigsegv;
 222
 223         push_cache((unsigned long)&frame->retcode, sizeof(frame->retcode));
 224
 225         /* Set up registers for signal handler */
 226         wrusp((unsigned long)frame);
 227         if (get_personality & FDPIC_FUNCPTRS) {
 228                 struct fdpic_func_descriptor __user *funcptr =
 229                         (struct fdpic_func_descriptor *) ka->sa.sa_handler;
 230                 __get_user(regs->pc, &funcptr->text);
 231                 __get_user(regs->p3, &funcptr->GOT);
 232         } else
 233                 regs->pc = (unsigned long)ka->sa.sa_handler;
 234         regs->rets = (unsigned long)(frame->retcode);
 235
 236         regs->r0 = frame->sig;
 237         regs->r1 = (unsigned long)(&frame->info);
 238         regs->r2 = (unsigned long)(&frame->uc);
 239
 240         return 0;
 241
 242       give_sigsegv:
 243         if (sig == SIGSEGV)
 244                 ka->sa.sa_handler = SIG_DFL;
 245         force_sig(SIGSEGV, current);
 246         return -EFAULT;
 247 }
 248
 249 static inline void
 250 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
 251 {
 252         switch (regs->r0) {
 253         case -ERESTARTNOHAND:
 254                 if (!has_handler)
 255                         goto do_restart;
 256                 regs->r0 = -EINTR;
 257                 break;
 258
 259         case -ERESTARTSYS:
 260                 if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
 261                         regs->r0 = -EINTR;
 262                         break;
 263                 }
 264                 /* fallthrough */
 265         case -ERESTARTNOINTR:
 266               do_restart:
 267                 regs->p0 = regs->orig_p0;
 268                 regs->r0 = regs->orig_r0;
 269                 regs->pc -= 2;
 270                 break;
 271         }
 272 }
 273
 274 /*
 275  * OK, we're invoking a handler
 276  */
 277 static int
 278 handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
 279               sigset_t *oldset, struct pt_regs *regs)
 280 {
 281         int ret;
 282
 283         /* are we from a system call? to see pt_regs->orig_p0 */
 284         if (regs->orig_p0 >= 0)
 285                 /* If so, check system call restarting.. */
 286                 handle_restart(regs, ka, 1);
 287
 288         /* set up the stack frame */
 289         ret = setup_rt_frame(sig, ka, info, oldset, regs);
 290
 291         if (ret == 0) {
 292                 spin_lock_irq(&current->sighand->siglock);
 293                 sigorsets(&current->blocked, &current->blocked,
 294                           &ka->sa.sa_mask);
 295                 if (!(ka->sa.sa_flags & SA_NODEFER))
 296                         sigaddset(&current->blocked, sig);
 297                 recalc_sigpending();
 298                 spin_unlock_irq(&current->sighand->siglock);
 299         }
 300         return ret;
 301 }
 302
 303 /*
 304  * Note that 'init' is a special process: it doesn't get signals it doesn't
 305  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 306  * mistake.
 307  *
 308  * Note that we go through the signals twice: once to check the signals
 309  * that the kernel can handle, and then we build all the user-level signal
 310  * handling stack-frames in one go after that.
 311  */
 312 asmlinkage void do_signal(struct pt_regs *regs)
 313 {
 314         siginfo_t info;
 315         int signr;
 316         struct k_sigaction ka;
 317         sigset_t *oldset;
 318
 319         current->thread.esp0 = (unsigned long)regs;
 320
 321         if (try_to_freeze())
 322                 goto no_signal;
 323
 324         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 325                 oldset = &current->saved_sigmask;
 326         else
 327                 oldset = &current->blocked;
 328
 329         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 330         if (signr > 0) {
 331                 /* Whee!  Actually deliver the signal.  */
 332                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 333                         /* a signal was successfully delivered; the saved
 334                          * sigmask will have been stored in the signal frame,
 335                          * and will be restored by sigreturn, so we can simply
 336                          * clear the TIF_RESTORE_SIGMASK flag */
 337                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 338                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 339                 }
 340
 341                 return;
 342         }
 343
 344 no_signal:
 345         /* Did we come from a system call? */
 346         if (regs->orig_p0 >= 0)
 347                 /* Restart the system call - no handlers present */
 348                 handle_restart(regs, NULL, 0);
 349
 350         /* if there's no signal to deliver, we just put the saved sigmask
 351          * back */
 352         if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 353                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 354                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 355         }
 356 }