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