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/freezer.h>
  24#include <linux/tracehook.h>
  25#include <asm/cacheflush.h>
  26#include <asm/ucontext.h>
  27#include <asm/uaccess.h>
  28
  29#define DEBUG_SIG 0
  30
  31asmlinkage int
  32sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
  33                unsigned long r2, unsigned long r3, unsigned long r4,
  34                unsigned long r5, unsigned long r6, struct pt_regs *regs)
  35{
  36        return do_sigaltstack(uss, uoss, regs->spu);
  37}
  38
  39
  40/*
  41 * Do a signal return; undo the signal stack.
  42 */
  43
  44struct rt_sigframe
  45{
  46        int sig;
  47        struct siginfo __user *pinfo;
  48        void __user *puc;
  49        struct siginfo info;
  50        struct ucontext uc;
  51//      struct _fpstate fpstate;
  52};
  53
  54static int
  55restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
  56                   int *r0_p)
  57{
  58        unsigned int err = 0;
  59
  60        /* Always make any pending restarted system calls return -EINTR */
  61        current_thread_info()->restart_block.fn = do_no_restart_syscall;
  62
  63#define COPY(x)         err |= __get_user(regs->x, &sc->sc_##x)
  64        COPY(r4);
  65        COPY(r5);
  66        COPY(r6);
  67        COPY(pt_regs);
  68        /* COPY(r0); Skip r0 */
  69        COPY(r1);
  70        COPY(r2);
  71        COPY(r3);
  72        COPY(r7);
  73        COPY(r8);
  74        COPY(r9);
  75        COPY(r10);
  76        COPY(r11);
  77        COPY(r12);
  78        COPY(acc0h);
  79        COPY(acc0l);
  80        COPY(acc1h);            /* ISA_DSP_LEVEL2 only */
  81        COPY(acc1l);            /* ISA_DSP_LEVEL2 only */
  82        COPY(psw);
  83        COPY(bpc);
  84        COPY(bbpsw);
  85        COPY(bbpc);
  86        COPY(spu);
  87        COPY(fp);
  88        COPY(lr);
  89        COPY(spi);
  90#undef COPY
  91
  92        regs->syscall_nr = -1;  /* disable syscall checks */
  93        err |= __get_user(*r0_p, &sc->sc_r0);
  94
  95        return err;
  96}
  97
  98asmlinkage int
  99sys_rt_sigreturn(unsigned long r0, unsigned long r1,
 100                 unsigned long r2, unsigned long r3, unsigned long r4,
 101                 unsigned long r5, unsigned long r6, struct pt_regs *regs)
 102{
 103        struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->spu;
 104        sigset_t set;
 105        int result;
 106
 107        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 108                goto badframe;
 109        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 110                goto badframe;
 111
 112        set_current_blocked(&set);
 113
 114        if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &result))
 115                goto badframe;
 116
 117        if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->spu) == -EFAULT)
 118                goto badframe;
 119
 120        return result;
 121
 122badframe:
 123        force_sig(SIGSEGV, current);
 124        return 0;
 125}
 126
 127/*
 128 * Set up a signal frame.
 129 */
 130
 131static int
 132setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 133                 unsigned long mask)
 134{
 135        int err = 0;
 136
 137#define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
 138        COPY(r4);
 139        COPY(r5);
 140        COPY(r6);
 141        COPY(pt_regs);
 142        COPY(r0);
 143        COPY(r1);
 144        COPY(r2);
 145        COPY(r3);
 146        COPY(r7);
 147        COPY(r8);
 148        COPY(r9);
 149        COPY(r10);
 150        COPY(r11);
 151        COPY(r12);
 152        COPY(acc0h);
 153        COPY(acc0l);
 154        COPY(acc1h);            /* ISA_DSP_LEVEL2 only */
 155        COPY(acc1l);            /* ISA_DSP_LEVEL2 only */
 156        COPY(psw);
 157        COPY(bpc);
 158        COPY(bbpsw);
 159        COPY(bbpc);
 160        COPY(spu);
 161        COPY(fp);
 162        COPY(lr);
 163        COPY(spi);
 164#undef COPY
 165
 166        err |= __put_user(mask, &sc->oldmask);
 167
 168        return err;
 169}
 170
 171/*
 172 * Determine which stack to use..
 173 */
 174static inline void __user *
 175get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
 176{
 177        /* This is the X/Open sanctioned signal stack switching.  */
 178        if (ka->sa.sa_flags & SA_ONSTACK) {
 179                if (sas_ss_flags(sp) == 0)
 180                        sp = current->sas_ss_sp + current->sas_ss_size;
 181        }
 182
 183        return (void __user *)((sp - frame_size) & -8ul);
 184}
 185
 186static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 187                           sigset_t *set, struct pt_regs *regs)
 188{
 189        struct rt_sigframe __user *frame;
 190        int err = 0;
 191        int signal;
 192
 193        frame = get_sigframe(ka, regs->spu, sizeof(*frame));
 194
 195        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 196                goto give_sigsegv;
 197
 198        signal = current_thread_info()->exec_domain
 199                && current_thread_info()->exec_domain->signal_invmap
 200                && sig < 32
 201                ? current_thread_info()->exec_domain->signal_invmap[sig]
 202                : sig;
 203
 204        err |= __put_user(signal, &frame->sig);
 205        if (err)
 206                goto give_sigsegv;
 207
 208        err |= __put_user(&frame->info, &frame->pinfo);
 209        err |= __put_user(&frame->uc, &frame->puc);
 210        err |= copy_siginfo_to_user(&frame->info, info);
 211        if (err)
 212                goto give_sigsegv;
 213
 214        /* Create the ucontext.  */
 215        err |= __put_user(0, &frame->uc.uc_flags);
 216        err |= __put_user(0, &frame->uc.uc_link);
 217        err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 218        err |= __put_user(sas_ss_flags(regs->spu),
 219                          &frame->uc.uc_stack.ss_flags);
 220        err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 221        err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
 222        err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 223        if (err)
 224                goto give_sigsegv;
 225
 226        /* Set up to return from userspace.  */
 227        regs->lr = (unsigned long)ka->sa.sa_restorer;
 228
 229        /* Set up registers for signal handler */
 230        regs->spu = (unsigned long)frame;
 231        regs->r0 = signal;      /* Arg for signal handler */
 232        regs->r1 = (unsigned long)&frame->info;
 233        regs->r2 = (unsigned long)&frame->uc;
 234        regs->bpc = (unsigned long)ka->sa.sa_handler;
 235
 236        set_fs(USER_DS);
 237
 238#if DEBUG_SIG
 239        printk("SIG deliver (%s:%d): sp=%p pc=%p\n",
 240                current->comm, current->pid, frame, regs->pc);
 241#endif
 242
 243        return 0;
 244
 245give_sigsegv:
 246        force_sigsegv(sig, current);
 247        return -EFAULT;
 248}
 249
 250static int prev_insn(struct pt_regs *regs)
 251{
 252        u16 inst;
 253        if (get_user(inst, (u16 __user *)(regs->bpc - 2)))
 254                return -EFAULT;
 255        if ((inst & 0xfff0) == 0x10f0)  /* trap ? */
 256                regs->bpc -= 2;
 257        else
 258                regs->bpc -= 4;
 259        regs->syscall_nr = -1;
 260        return 0;
 261}
 262
 263/*
 264 * OK, we're invoking a handler
 265 */
 266
 267static void
 268handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
 269              struct pt_regs *regs)
 270{
 271        /* Are we from a system call? */
 272        if (regs->syscall_nr >= 0) {
 273                /* If so, check system call restarting.. */
 274                switch (regs->r0) {
 275                        case -ERESTART_RESTARTBLOCK:
 276                        case -ERESTARTNOHAND:
 277                                regs->r0 = -EINTR;
 278                                break;
 279
 280                        case -ERESTARTSYS:
 281                                if (!(ka->sa.sa_flags & SA_RESTART)) {
 282                                        regs->r0 = -EINTR;
 283                                        break;
 284                                }
 285                        /* fallthrough */
 286                        case -ERESTARTNOINTR:
 287                                regs->r0 = regs->orig_r0;
 288                                if (prev_insn(regs) < 0)
 289                                        return;
 290                }
 291        }
 292
 293        /* Set up the stack frame */
 294        if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs))
 295                return;
 296
 297        signal_delivered(sig, info, ka, regs, 0);
 298}
 299
 300/*
 301 * Note that 'init' is a special process: it doesn't get signals it doesn't
 302 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 303 * mistake.
 304 */
 305static void do_signal(struct pt_regs *regs)
 306{
 307        siginfo_t info;
 308        int signr;
 309        struct k_sigaction ka;
 310
 311        /*
 312         * We want the common case to go fast, which
 313         * is why we may in certain cases get here from
 314         * kernel mode. Just return without doing anything
 315         * if so.
 316         */
 317        if (!user_mode(regs))
 318                return;
 319
 320        signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 321        if (signr > 0) {
 322                /* Re-enable any watchpoints before delivering the
 323                 * signal to user space. The processor register will
 324                 * have been cleared if the watchpoint triggered
 325                 * inside the kernel.
 326                 */
 327
 328                /* Whee!  Actually deliver the signal.  */
 329                handle_signal(signr, &ka, &info, regs);
 330
 331                return;
 332        }
 333
 334        /* Did we come from a system call? */
 335        if (regs->syscall_nr >= 0) {
 336                /* Restart the system call - no handlers present */
 337                if (regs->r0 == -ERESTARTNOHAND ||
 338                    regs->r0 == -ERESTARTSYS ||
 339                    regs->r0 == -ERESTARTNOINTR) {
 340                        regs->r0 = regs->orig_r0;
 341                        prev_insn(regs);
 342                } else if (regs->r0 == -ERESTART_RESTARTBLOCK){
 343                        regs->r0 = regs->orig_r0;
 344                        regs->r7 = __NR_restart_syscall;
 345                        prev_insn(regs);
 346                }
 347        }
 348        restore_saved_sigmask();
 349}
 350
 351/*
 352 * notification of userspace execution resumption
 353 * - triggered by current->work.notify_resume
 354 */
 355void do_notify_resume(struct pt_regs *regs, __u32 thread_info_flags)
 356{
 357        /* Pending single-step? */
 358        if (thread_info_flags & _TIF_SINGLESTEP)
 359                clear_thread_flag(TIF_SINGLESTEP);
 360
 361        /* deal with pending signal delivery */
 362        if (thread_info_flags & _TIF_SIGPENDING)
 363                do_signal(regs);
 364
 365        if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 366                clear_thread_flag(TIF_NOTIFY_RESUME);
 367                tracehook_notify_resume(regs);
 368        }
 369
 370        clear_thread_flag(TIF_IRET);
 371}
 372