linux/arch/h8300/kernel/signal.c
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   1/*
   2 *  linux/arch/h8300/kernel/signal.c
   3 *
   4 *  Copyright (C) 1991, 1992  Linus Torvalds
   5 *
   6 * This file is subject to the terms and conditions of the GNU General Public
   7 * License.  See the file COPYING in the main directory of this archive
   8 * for more details.
   9 */
  10
  11/*
  12 * uClinux H8/300 support by Yoshinori Sato <ysato@users.sourceforge.jp>
  13 *                and David McCullough <davidm@snapgear.com>
  14 *
  15 * Based on
  16 * Linux/m68k by Hamish Macdonald
  17 */
  18
  19/*
  20 * ++roman (07/09/96): implemented signal stacks (specially for tosemu on
  21 * Atari :-) Current limitation: Only one sigstack can be active at one time.
  22 * If a second signal with SA_ONSTACK set arrives while working on a sigstack,
  23 * SA_ONSTACK is ignored. This behaviour avoids lots of trouble with nested
  24 * signal handlers!
  25 */
  26
  27#include <linux/sched.h>
  28#include <linux/sched/task_stack.h>
  29#include <linux/mm.h>
  30#include <linux/kernel.h>
  31#include <linux/signal.h>
  32#include <linux/syscalls.h>
  33#include <linux/errno.h>
  34#include <linux/wait.h>
  35#include <linux/ptrace.h>
  36#include <linux/unistd.h>
  37#include <linux/stddef.h>
  38#include <linux/highuid.h>
  39#include <linux/personality.h>
  40#include <linux/tty.h>
  41#include <linux/binfmts.h>
  42#include <linux/tracehook.h>
  43
  44#include <asm/setup.h>
  45#include <linux/uaccess.h>
  46#include <asm/pgtable.h>
  47#include <asm/traps.h>
  48#include <asm/ucontext.h>
  49
  50/*
  51 * Do a signal return; undo the signal stack.
  52 *
  53 * Keep the return code on the stack quadword aligned!
  54 * That makes the cache flush below easier.
  55 */
  56
  57struct rt_sigframe {
  58        long dummy_er0;
  59        long dummy_vector;
  60#if defined(CONFIG_CPU_H8S)
  61        short dummy_exr;
  62#endif
  63        long dummy_pc;
  64        char *pretcode;
  65        struct siginfo *pinfo;
  66        void *puc;
  67        unsigned char retcode[8];
  68        struct siginfo info;
  69        struct ucontext uc;
  70        int sig;
  71} __packed __aligned(2);
  72
  73static inline int
  74restore_sigcontext(struct sigcontext *usc, int *pd0)
  75{
  76        struct pt_regs *regs = current_pt_regs();
  77        int err = 0;
  78        unsigned int ccr;
  79        unsigned int usp;
  80        unsigned int er0;
  81
  82        /* Always make any pending restarted system calls return -EINTR */
  83        current->restart_block.fn = do_no_restart_syscall;
  84
  85        /* restore passed registers */
  86#define COPY(r)  do { err |= get_user(regs->r, &usc->sc_##r); } while (0)
  87        COPY(er1);
  88        COPY(er2);
  89        COPY(er3);
  90        COPY(er5);
  91        COPY(pc);
  92        ccr = regs->ccr & 0x10;
  93        COPY(ccr);
  94#undef COPY
  95        regs->ccr &= 0xef;
  96        regs->ccr |= ccr;
  97        regs->orig_er0 = -1;            /* disable syscall checks */
  98        err |= __get_user(usp, &usc->sc_usp);
  99        regs->sp = usp;
 100
 101        err |= __get_user(er0, &usc->sc_er0);
 102        *pd0 = er0;
 103        return err;
 104}
 105
 106asmlinkage int sys_rt_sigreturn(void)
 107{
 108        unsigned long usp = rdusp();
 109        struct rt_sigframe *frame = (struct rt_sigframe *)(usp - 4);
 110        sigset_t set;
 111        int er0;
 112
 113        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 114                goto badframe;
 115        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 116                goto badframe;
 117
 118        set_current_blocked(&set);
 119
 120        if (restore_sigcontext(&frame->uc.uc_mcontext, &er0))
 121                goto badframe;
 122
 123        if (restore_altstack(&frame->uc.uc_stack))
 124                goto badframe;
 125
 126        return er0;
 127
 128badframe:
 129        force_sig(SIGSEGV, current);
 130        return 0;
 131}
 132
 133static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 134                             unsigned long mask)
 135{
 136        int err = 0;
 137
 138        err |= __put_user(regs->er0, &sc->sc_er0);
 139        err |= __put_user(regs->er1, &sc->sc_er1);
 140        err |= __put_user(regs->er2, &sc->sc_er2);
 141        err |= __put_user(regs->er3, &sc->sc_er3);
 142        err |= __put_user(regs->er4, &sc->sc_er4);
 143        err |= __put_user(regs->er5, &sc->sc_er5);
 144        err |= __put_user(regs->er6, &sc->sc_er6);
 145        err |= __put_user(rdusp(),   &sc->sc_usp);
 146        err |= __put_user(regs->pc,  &sc->sc_pc);
 147        err |= __put_user(regs->ccr, &sc->sc_ccr);
 148        err |= __put_user(mask,      &sc->sc_mask);
 149
 150        return err;
 151}
 152
 153static inline void __user *
 154get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size)
 155{
 156        return (void __user *)((sigsp(rdusp(), ksig) - frame_size) & -8UL);
 157}
 158
 159static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
 160                          struct pt_regs *regs)
 161{
 162        struct rt_sigframe *frame;
 163        int err = 0;
 164        unsigned char *ret;
 165
 166        frame = get_sigframe(ksig, regs, sizeof(*frame));
 167
 168        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 169                return -EFAULT;
 170
 171        if (ksig->ka.sa.sa_flags & SA_SIGINFO)
 172                err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 173
 174        /* Create the ucontext.  */
 175        err |= __put_user(0, &frame->uc.uc_flags);
 176        err |= __put_user(0, &frame->uc.uc_link);
 177        err |= __save_altstack(&frame->uc.uc_stack, rdusp());
 178        err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
 179        err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 180        if (err)
 181                return -EFAULT;
 182
 183        /* Set up to return from userspace.  */
 184        ret = (unsigned char *)&frame->retcode;
 185        if (ksig->ka.sa.sa_flags & SA_RESTORER)
 186                ret = (unsigned char *)(ksig->ka.sa.sa_restorer);
 187        else {
 188                /* sub.l er0,er0; mov.b #__NR_rt_sigreturn,r0l; trapa #0 */
 189                err |= __put_user(0x1a80f800 + (__NR_rt_sigreturn & 0xff),
 190                                  (unsigned long *)(frame->retcode + 0));
 191                err |= __put_user(0x5700,
 192                                  (unsigned short *)(frame->retcode + 4));
 193        }
 194        err |= __put_user(ret, &frame->pretcode);
 195
 196        if (err)
 197                return -EFAULT;
 198
 199        /* Set up registers for signal handler */
 200        regs->sp  = (unsigned long)frame;
 201        regs->pc  = (unsigned long)ksig->ka.sa.sa_handler;
 202        regs->er0 = ksig->sig;
 203        regs->er1 = (unsigned long)&(frame->info);
 204        regs->er2 = (unsigned long)&frame->uc;
 205        regs->er5 = current->mm->start_data;    /* GOT base */
 206
 207        return 0;
 208}
 209
 210static void
 211handle_restart(struct pt_regs *regs, struct k_sigaction *ka)
 212{
 213        switch (regs->er0) {
 214        case -ERESTARTNOHAND:
 215                if (!ka)
 216                        goto do_restart;
 217                regs->er0 = -EINTR;
 218                break;
 219        case -ERESTART_RESTARTBLOCK:
 220                if (!ka) {
 221                        regs->er0 = __NR_restart_syscall;
 222                        regs->pc -= 2;
 223                } else
 224                        regs->er0 = -EINTR;
 225                break;
 226        case -ERESTARTSYS:
 227                if (!(ka->sa.sa_flags & SA_RESTART)) {
 228                        regs->er0 = -EINTR;
 229                        break;
 230                }
 231                /* fallthrough */
 232        case -ERESTARTNOINTR:
 233do_restart:
 234                regs->er0 = regs->orig_er0;
 235                regs->pc -= 2;
 236                break;
 237        }
 238}
 239
 240/*
 241 * OK, we're invoking a handler
 242 */
 243static void
 244handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 245{
 246        sigset_t *oldset = sigmask_to_save();
 247        int ret;
 248        /* are we from a system call? */
 249        if (regs->orig_er0 >= 0)
 250                handle_restart(regs, &ksig->ka);
 251
 252        ret = setup_rt_frame(ksig, oldset, regs);
 253
 254        signal_setup_done(ret, ksig, 0);
 255}
 256
 257/*
 258 * Note that 'init' is a special process: it doesn't get signals it doesn't
 259 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 260 * mistake.
 261 */
 262static void do_signal(struct pt_regs *regs)
 263{
 264        struct ksignal ksig;
 265
 266        current->thread.esp0 = (unsigned long) regs;
 267
 268        if (get_signal(&ksig)) {
 269                /* Whee!  Actually deliver the signal.  */
 270                handle_signal(&ksig, regs);
 271                return;
 272        }
 273        /* Did we come from a system call? */
 274        if (regs->orig_er0 >= 0)
 275                handle_restart(regs, NULL);
 276
 277        /* If there's no signal to deliver, we just restore the saved mask.  */
 278        restore_saved_sigmask();
 279}
 280
 281asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
 282{
 283        if (thread_info_flags & _TIF_SIGPENDING)
 284                do_signal(regs);
 285
 286        if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 287                clear_thread_flag(TIF_NOTIFY_RESUME);
 288                tracehook_notify_resume(regs);
 289        }
 290}
 291