LXR linux/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/tracehook.h>
  24#include <asm/cacheflush.h>
  25#include <asm/ucontext.h>
  26#include <asm/uaccess.h>
  27
  28#define DEBUG_SIG 0
  29
  30asmlinkage int
  31sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
  32                unsigned long r2, unsigned long r3, unsigned long r4,
  33                unsigned long r5, unsigned long r6, struct pt_regs *regs)
  34{
  35        return do_sigaltstack(uss, uoss, regs->spu);
  36}
  37
  38
  39/*
  40 * Do a signal return; undo the signal stack.
  41 */
  42
  43struct rt_sigframe
  44{
  45        int sig;
  46        struct siginfo __user *pinfo;
  47        void __user *puc;
  48        struct siginfo info;
  49        struct ucontext uc;
  50//      struct _fpstate fpstate;
  51};
  52
  53static int
  54restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
  55                   int *r0_p)
  56{
  57        unsigned int err = 0;
  58
  59        /* Always make any pending restarted system calls return -EINTR */
  60        current_thread_info()->restart_block.fn = do_no_restart_syscall;
  61
  62#define COPY(x)         err |= __get_user(regs->x, &sc->sc_##x)
  63        COPY(r4);
  64        COPY(r5);
  65        COPY(r6);
  66        COPY(pt_regs);
  67        /* COPY(r0); Skip r0 */
  68        COPY(r1);
  69        COPY(r2);
  70        COPY(r3);
  71        COPY(r7);
  72        COPY(r8);
  73        COPY(r9);
  74        COPY(r10);
  75        COPY(r11);
  76        COPY(r12);
  77        COPY(acc0h);
  78        COPY(acc0l);
  79        COPY(acc1h);            /* ISA_DSP_LEVEL2 only */
  80        COPY(acc1l);            /* ISA_DSP_LEVEL2 only */
  81        COPY(psw);
  82        COPY(bpc);
  83        COPY(bbpsw);
  84        COPY(bbpc);
  85        COPY(spu);
  86        COPY(fp);
  87        COPY(lr);
  88        COPY(spi);
  89#undef COPY
  90
  91        regs->syscall_nr = -1;  /* disable syscall checks */
  92        err |= __get_user(*r0_p, &sc->sc_r0);
  93
  94        return err;
  95}
  96
  97asmlinkage int
  98sys_rt_sigreturn(unsigned long r0, unsigned long r1,
  99                 unsigned long r2, unsigned long r3, unsigned long r4,
 100                 unsigned long r5, unsigned long r6, struct pt_regs *regs)
 101{
 102        struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->spu;
 103        sigset_t set;
 104        int result;
 105
 106        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 107                goto badframe;
 108        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 109                goto badframe;
 110
 111        set_current_blocked(&set);
 112
 113        if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &result))
 114                goto badframe;
 115
 116        if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->spu) == -EFAULT)
 117                goto badframe;
 118
 119        return result;
 120
 121badframe:
 122        force_sig(SIGSEGV, current);
 123        return 0;
 124}
 125
 126/*
 127 * Set up a signal frame.
 128 */
 129
 130static int
 131setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 132                 unsigned long mask)
 133{
 134        int err = 0;
 135
 136#define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
 137        COPY(r4);
 138        COPY(r5);
 139        COPY(r6);
 140        COPY(pt_regs);
 141        COPY(r0);
 142        COPY(r1);
 143        COPY(r2);
 144        COPY(r3);
 145        COPY(r7);
 146        COPY(r8);
 147        COPY(r9);
 148        COPY(r10);
 149        COPY(r11);
 150        COPY(r12);
 151        COPY(acc0h);
 152        COPY(acc0l);
 153        COPY(acc1h);            /* ISA_DSP_LEVEL2 only */
 154        COPY(acc1l);            /* ISA_DSP_LEVEL2 only */
 155        COPY(psw);
 156        COPY(bpc);
 157        COPY(bbpsw);
 158        COPY(bbpc);
 159        COPY(spu);
 160        COPY(fp);
 161        COPY(lr);
 162        COPY(spi);
 163#undef COPY
 164
 165        err |= __put_user(mask, &sc->oldmask);
 166
 167        return err;
 168}
 169
 170/*
 171 * Determine which stack to use..
 172 */
 173static inline void __user *
 174get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
 175{
 176        /* This is the X/Open sanctioned signal stack switching.  */
 177        if (ka->sa.sa_flags & SA_ONSTACK) {
 178                if (sas_ss_flags(sp) == 0)
 179                        sp = current->sas_ss_sp + current->sas_ss_size;
 180        }
 181
 182        return (void __user *)((sp - frame_size) & -8ul);
 183}
 184
 185static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 186                           sigset_t *set, struct pt_regs *regs)
 187{
 188        struct rt_sigframe __user *frame;
 189        int err = 0;
 190        int signal;
 191
 192        frame = get_sigframe(ka, regs->spu, sizeof(*frame));
 193
 194        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 195                goto give_sigsegv;
 196
 197        signal = current_thread_info()->exec_domain
 198                && current_thread_info()->exec_domain->signal_invmap
 199                && sig < 32
 200                ? current_thread_info()->exec_domain->signal_invmap[sig]
 201                : sig;
 202
 203        err |= __put_user(signal, &frame->sig);
 204        if (err)
 205                goto give_sigsegv;
 206
 207        err |= __put_user(&frame->info, &frame->pinfo);
 208        err |= __put_user(&frame->uc, &frame->puc);
 209        err |= copy_siginfo_to_user(&frame->info, info);
 210        if (err)
 211                goto give_sigsegv;
 212
 213        /* Create the ucontext.  */
 214        err |= __put_user(0, &frame->uc.uc_flags);
 215        err |= __put_user(0, &frame->uc.uc_link);
 216        err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 217        err |= __put_user(sas_ss_flags(regs->spu),
 218                          &frame->uc.uc_stack.ss_flags);
 219        err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 220        err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
 221        err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 222        if (err)
 223                goto give_sigsegv;
 224
 225        /* Set up to return from userspace.  */
 226        regs->lr = (unsigned long)ka->sa.sa_restorer;
 227
 228        /* Set up registers for signal handler */
 229        regs->spu = (unsigned long)frame;
 230        regs->r0 = signal;      /* Arg for signal handler */
 231        regs->r1 = (unsigned long)&frame->info;
 232        regs->r2 = (unsigned long)&frame->uc;
 233        regs->bpc = (unsigned long)ka->sa.sa_handler;
 234
 235        set_fs(USER_DS);
 236
 237#if DEBUG_SIG
 238        printk("SIG deliver (%s:%d): sp=%p pc=%p\n",
 239                current->comm, current->pid, frame, regs->pc);
 240#endif
 241
 242        return 0;
 243
 244give_sigsegv:
 245        force_sigsegv(sig, current);
 246        return -EFAULT;
 247}
 248
 249static int prev_insn(struct pt_regs *regs)
 250{
 251        u16 inst;
 252        if (get_user(inst, (u16 __user *)(regs->bpc - 2)))
 253                return -EFAULT;
 254        if ((inst & 0xfff0) == 0x10f0)  /* trap ? */
 255                regs->bpc -= 2;
 256        else
 257                regs->bpc -= 4;
 258        regs->syscall_nr = -1;
 259        return 0;
 260}
 261
 262/*
 263 * OK, we're invoking a handler
 264 */
 265
 266static void
 267handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
 268              struct pt_regs *regs)
 269{
 270        /* Are we from a system call? */
 271        if (regs->syscall_nr >= 0) {
 272                /* If so, check system call restarting.. */
 273                switch (regs->r0) {
 274                        case -ERESTART_RESTARTBLOCK:
 275                        case -ERESTARTNOHAND:
 276                                regs->r0 = -EINTR;
 277                                break;
 278
 279                        case -ERESTARTSYS:
 280                                if (!(ka->sa.sa_flags & SA_RESTART)) {
 281                                        regs->r0 = -EINTR;
 282                                        break;
 283                                }
 284                        /* fallthrough */
 285                        case -ERESTARTNOINTR:
 286                                regs->r0 = regs->orig_r0;
 287                                if (prev_insn(regs) < 0)
 288                                        return;
 289                }
 290        }
 291
 292        /* Set up the stack frame */
 293        if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs))
 294                return;
 295
 296        signal_delivered(sig, info, ka, regs, 0);
 297}
 298
 299/*
 300 * Note that 'init' is a special process: it doesn't get signals it doesn't
 301 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 302 * mistake.
 303 */
 304static void do_signal(struct pt_regs *regs)
 305{
 306        siginfo_t info;
 307        int signr;
 308        struct k_sigaction ka;
 309
 310        /*
 311         * We want the common case to go fast, which
 312         * is why we may in certain cases get here from
 313         * kernel mode. Just return without doing anything
 314         * if so.
 315         */
 316        if (!user_mode(regs))
 317                return;
 318
 319        signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 320        if (signr > 0) {
 321                /* Re-enable any watchpoints before delivering the
 322                 * signal to user space. The processor register will
 323                 * have been cleared if the watchpoint triggered
 324                 * inside the kernel.
 325                 */
 326
 327                /* Whee!  Actually deliver the signal.  */
 328                handle_signal(signr, &ka, &info, regs);
 329
 330                return;
 331        }
 332
 333        /* Did we come from a system call? */
 334        if (regs->syscall_nr >= 0) {
 335                /* Restart the system call - no handlers present */
 336                if (regs->r0 == -ERESTARTNOHAND ||
 337                    regs->r0 == -ERESTARTSYS ||
 338                    regs->r0 == -ERESTARTNOINTR) {
 339                        regs->r0 = regs->orig_r0;
 340                        prev_insn(regs);
 341                } else if (regs->r0 == -ERESTART_RESTARTBLOCK){
 342                        regs->r0 = regs->orig_r0;
 343                        regs->r7 = __NR_restart_syscall;
 344                        prev_insn(regs);
 345                }
 346        }
 347        restore_saved_sigmask();
 348}
 349
 350/*
 351 * notification of userspace execution resumption
 352 * - triggered by current->work.notify_resume
 353 */
 354void do_notify_resume(struct pt_regs *regs, __u32 thread_info_flags)
 355{
 356        /* Pending single-step? */
 357        if (thread_info_flags & _TIF_SINGLESTEP)
 358                clear_thread_flag(TIF_SINGLESTEP);
 359
 360        /* deal with pending signal delivery */
 361        if (thread_info_flags & _TIF_SIGPENDING)
 362                do_signal(regs);
 363
 364        if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 365                clear_thread_flag(TIF_NOTIFY_RESUME);
 366                tracehook_notify_resume(regs);
 367        }
 368}
 369