linux/arch/blackfin/kernel/signal.c
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   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
  24struct fdpic_func_descriptor {
  25        unsigned long   text;
  26        unsigned long   GOT;
  27};
  28
  29struct 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
  40static inline int
  41rt_restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *pr0)
  42{
  43        unsigned long usp = 0;
  44        int err = 0;
  45
  46        /* Always make any pending restarted system calls return -EINTR */
  47        current_thread_info()->restart_block.fn = do_no_restart_syscall;
  48
  49#define RESTORE(x) err |= __get_user(regs->x, &sc->sc_##x)
  50
  51        /* restore passed registers */
  52        RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3);
  53        RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7);
  54        RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3);
  55        RESTORE(p4); RESTORE(p5);
  56        err |= __get_user(usp, &sc->sc_usp);
  57        wrusp(usp);
  58        RESTORE(a0w); RESTORE(a1w);
  59        RESTORE(a0x); RESTORE(a1x);
  60        RESTORE(astat);
  61        RESTORE(rets);
  62        RESTORE(pc);
  63        RESTORE(retx);
  64        RESTORE(fp);
  65        RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3);
  66        RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3);
  67        RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3);
  68        RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3);
  69        RESTORE(lc0); RESTORE(lc1);
  70        RESTORE(lt0); RESTORE(lt1);
  71        RESTORE(lb0); RESTORE(lb1);
  72        RESTORE(seqstat);
  73
  74        regs->orig_p0 = -1;     /* disable syscall checks */
  75
  76        *pr0 = regs->r0;
  77        return err;
  78}
  79
  80asmlinkage int sys_rt_sigreturn(void)
  81{
  82        struct pt_regs *regs = current_pt_regs();
  83        unsigned long usp = rdusp();
  84        struct rt_sigframe *frame = (struct rt_sigframe *)(usp);
  85        sigset_t set;
  86        int r0;
  87
  88        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  89                goto badframe;
  90        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
  91                goto badframe;
  92
  93        set_current_blocked(&set);
  94
  95        if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
  96                goto badframe;
  97
  98        if (restore_altstack(&frame->uc.uc_stack))
  99                goto badframe;
 100
 101        return r0;
 102
 103 badframe:
 104        force_sig(SIGSEGV, current);
 105        return 0;
 106}
 107
 108static inline int rt_setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs)
 109{
 110        int err = 0;
 111
 112#define SETUP(x) err |= __put_user(regs->x, &sc->sc_##x)
 113
 114        SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3);
 115        SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7);
 116        SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3);
 117        SETUP(p4); SETUP(p5);
 118        err |= __put_user(rdusp(), &sc->sc_usp);
 119        SETUP(a0w); SETUP(a1w);
 120        SETUP(a0x); SETUP(a1x);
 121        SETUP(astat);
 122        SETUP(rets);
 123        SETUP(pc);
 124        SETUP(retx);
 125        SETUP(fp);
 126        SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3);
 127        SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3);
 128        SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3);
 129        SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3);
 130        SETUP(lc0); SETUP(lc1);
 131        SETUP(lt0); SETUP(lt1);
 132        SETUP(lb0); SETUP(lb1);
 133        SETUP(seqstat);
 134
 135        return err;
 136}
 137
 138static inline void *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 139                                 size_t frame_size)
 140{
 141        unsigned long usp;
 142
 143        /* Default to using normal stack.  */
 144        usp = rdusp();
 145
 146        /* This is the X/Open sanctioned signal stack switching.  */
 147        if (ka->sa.sa_flags & SA_ONSTACK) {
 148                if (!on_sig_stack(usp))
 149                        usp = current->sas_ss_sp + current->sas_ss_size;
 150        }
 151        return (void *)((usp - frame_size) & -8UL);
 152}
 153
 154static int
 155setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info,
 156               sigset_t * set, struct pt_regs *regs)
 157{
 158        struct rt_sigframe *frame;
 159        int err = 0;
 160
 161        frame = get_sigframe(ka, regs, sizeof(*frame));
 162
 163        err |= __put_user((current_thread_info()->exec_domain
 164                           && current_thread_info()->exec_domain->signal_invmap
 165                           && sig < 32
 166                           ? current_thread_info()->exec_domain->
 167                           signal_invmap[sig] : sig), &frame->sig);
 168
 169        err |= __put_user(&frame->info, &frame->pinfo);
 170        err |= __put_user(&frame->uc, &frame->puc);
 171        err |= copy_siginfo_to_user(&frame->info, info);
 172
 173        /* Create the ucontext.  */
 174        err |= __put_user(0, &frame->uc.uc_flags);
 175        err |= __put_user(0, &frame->uc.uc_link);
 176        err |= __save_altstack(&frame->uc.uc_stack, rdusp());
 177        err |= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
 178        err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 179
 180        if (err)
 181                return -EFAULT;
 182
 183        /* Set up registers for signal handler */
 184        if (current->personality & FDPIC_FUNCPTRS) {
 185                struct fdpic_func_descriptor __user *funcptr =
 186                        (struct fdpic_func_descriptor *) ka->sa.sa_handler;
 187                u32 pc, p3;
 188                err |= __get_user(pc, &funcptr->text);
 189                err |= __get_user(p3, &funcptr->GOT);
 190                if (err)
 191                        return -EFAULT;
 192                regs->pc = pc;
 193                regs->p3 = p3;
 194        } else
 195                regs->pc = (unsigned long)ka->sa.sa_handler;
 196        wrusp((unsigned long)frame);
 197        regs->rets = SIGRETURN_STUB;
 198
 199        regs->r0 = frame->sig;
 200        regs->r1 = (unsigned long)(&frame->info);
 201        regs->r2 = (unsigned long)(&frame->uc);
 202
 203        return 0;
 204}
 205
 206static inline void
 207handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
 208{
 209        switch (regs->r0) {
 210        case -ERESTARTNOHAND:
 211                if (!has_handler)
 212                        goto do_restart;
 213                regs->r0 = -EINTR;
 214                break;
 215
 216        case -ERESTARTSYS:
 217                if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
 218                        regs->r0 = -EINTR;
 219                        break;
 220                }
 221                /* fallthrough */
 222        case -ERESTARTNOINTR:
 223 do_restart:
 224                regs->p0 = regs->orig_p0;
 225                regs->r0 = regs->orig_r0;
 226                regs->pc -= 2;
 227                break;
 228
 229        case -ERESTART_RESTARTBLOCK:
 230                regs->p0 = __NR_restart_syscall;
 231                regs->pc -= 2;
 232                break;
 233        }
 234}
 235
 236/*
 237 * OK, we're invoking a handler
 238 */
 239static void
 240handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
 241              struct pt_regs *regs)
 242{
 243        /* are we from a system call? to see pt_regs->orig_p0 */
 244        if (regs->orig_p0 >= 0)
 245                /* If so, check system call restarting.. */
 246                handle_restart(regs, ka, 1);
 247
 248        /* set up the stack frame */
 249        if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs) < 0)
 250                force_sigsegv(sig, current);
 251        else 
 252                signal_delivered(sig, info, ka, regs,
 253                                test_thread_flag(TIF_SINGLESTEP));
 254}
 255
 256/*
 257 * Note that 'init' is a special process: it doesn't get signals it doesn't
 258 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 259 * mistake.
 260 *
 261 * Note that we go through the signals twice: once to check the signals
 262 * that the kernel can handle, and then we build all the user-level signal
 263 * handling stack-frames in one go after that.
 264 */
 265asmlinkage void do_signal(struct pt_regs *regs)
 266{
 267        siginfo_t info;
 268        int signr;
 269        struct k_sigaction ka;
 270
 271        current->thread.esp0 = (unsigned long)regs;
 272
 273        signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 274        if (signr > 0) {
 275                /* Whee!  Actually deliver the signal.  */
 276                handle_signal(signr, &info, &ka, regs);
 277                return;
 278        }
 279
 280        /* Did we come from a system call? */
 281        if (regs->orig_p0 >= 0)
 282                /* Restart the system call - no handlers present */
 283                handle_restart(regs, NULL, 0);
 284
 285        /* if there's no signal to deliver, we just put the saved sigmask
 286         * back */
 287        restore_saved_sigmask();
 288}
 289
 290/*
 291 * notification of userspace execution resumption
 292 */
 293asmlinkage void do_notify_resume(struct pt_regs *regs)
 294{
 295        if (test_thread_flag(TIF_SIGPENDING))
 296                do_signal(regs);
 297
 298        if (test_thread_flag(TIF_NOTIFY_RESUME)) {
 299                clear_thread_flag(TIF_NOTIFY_RESUME);
 300                tracehook_notify_resume(regs);
 301        }
 302}
 303
 304
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