arch/h8300/kernel/signal.c

   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/traps.h>
  47 #include <asm/ucontext.h>
  48
  49 /*
  50  * Do a signal return; undo the signal stack.
  51  *
  52  * Keep the return code on the stack quadword aligned!
  53  * That makes the cache flush below easier.
  54  */
  55
  56 struct rt_sigframe {
  57         long dummy_er0;
  58         long dummy_vector;
  59 #if defined(CONFIG_CPU_H8S)
  60         short dummy_exr;
  61 #endif
  62         long dummy_pc;
  63         char *pretcode;
  64         struct siginfo *pinfo;
  65         void *puc;
  66         unsigned char retcode[8];
  67         struct siginfo info;
  68         struct ucontext uc;
  69         int sig;
  70 } __packed __aligned(2);
  71
  72 static inline int
  73 restore_sigcontext(struct sigcontext *usc, int *pd0)
  74 {
  75         struct pt_regs *regs = current_pt_regs();
  76         int err = 0;
  77         unsigned int ccr;
  78         unsigned int usp;
  79         unsigned int er0;
  80
  81         /* Always make any pending restarted system calls return -EINTR */
  82         current->restart_block.fn = do_no_restart_syscall;
  83
  84         /* restore passed registers */
  85 #define COPY(r)  do { err |= get_user(regs->r, &usc->sc_##r); } while (0)
  86         COPY(er1);
  87         COPY(er2);
  88         COPY(er3);
  89         COPY(er5);
  90         COPY(pc);
  91         ccr = regs->ccr & 0x10;
  92         COPY(ccr);
  93 #undef COPY
  94         regs->ccr &= 0xef;
  95         regs->ccr |= ccr;
  96         regs->orig_er0 = -1;            /* disable syscall checks */
  97         err |= __get_user(usp, &usc->sc_usp);
  98         regs->sp = usp;
  99
 100         err |= __get_user(er0, &usc->sc_er0);
 101         *pd0 = er0;
 102         return err;
 103 }
 104
 105 asmlinkage int sys_rt_sigreturn(void)
 106 {
 107         unsigned long usp = rdusp();
 108         struct rt_sigframe *frame = (struct rt_sigframe *)(usp - 4);
 109         sigset_t set;
 110         int er0;
 111
 112         if (!access_ok(frame, sizeof(*frame)))
 113                 goto badframe;
 114         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 115                 goto badframe;
 116
 117         set_current_blocked(&set);
 118
 119         if (restore_sigcontext(&frame->uc.uc_mcontext, &er0))
 120                 goto badframe;
 121
 122         if (restore_altstack(&frame->uc.uc_stack))
 123                 goto badframe;
 124
 125         return er0;
 126
 127 badframe:
 128         force_sig(SIGSEGV);
 129         return 0;
 130 }
 131
 132 static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 133                              unsigned long mask)
 134 {
 135         int err = 0;
 136
 137         err |= __put_user(regs->er0, &sc->sc_er0);
 138         err |= __put_user(regs->er1, &sc->sc_er1);
 139         err |= __put_user(regs->er2, &sc->sc_er2);
 140         err |= __put_user(regs->er3, &sc->sc_er3);
 141         err |= __put_user(regs->er4, &sc->sc_er4);
 142         err |= __put_user(regs->er5, &sc->sc_er5);
 143         err |= __put_user(regs->er6, &sc->sc_er6);
 144         err |= __put_user(rdusp(),   &sc->sc_usp);
 145         err |= __put_user(regs->pc,  &sc->sc_pc);
 146         err |= __put_user(regs->ccr, &sc->sc_ccr);
 147         err |= __put_user(mask,      &sc->sc_mask);
 148
 149         return err;
 150 }
 151
 152 static inline void __user *
 153 get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size)
 154 {
 155         return (void __user *)((sigsp(rdusp(), ksig) - frame_size) & -8UL);
 156 }
 157
 158 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
 159                           struct pt_regs *regs)
 160 {
 161         struct rt_sigframe *frame;
 162         int err = 0;
 163         unsigned char *ret;
 164
 165         frame = get_sigframe(ksig, regs, sizeof(*frame));
 166
 167         if (!access_ok(frame, sizeof(*frame)))
 168                 return -EFAULT;
 169
 170         if (ksig->ka.sa.sa_flags & SA_SIGINFO)
 171                 err |= copy_siginfo_to_user(&frame->info, &ksig->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 |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
 178         err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 179         if (err)
 180                 return -EFAULT;
 181
 182         /* Set up to return from userspace.  */
 183         ret = (unsigned char *)&frame->retcode;
 184         if (ksig->ka.sa.sa_flags & SA_RESTORER)
 185                 ret = (unsigned char *)(ksig->ka.sa.sa_restorer);
 186         else {
 187                 /* sub.l er0,er0; mov.b #__NR_rt_sigreturn,r0l; trapa #0 */
 188                 err |= __put_user(0x1a80f800 + (__NR_rt_sigreturn & 0xff),
 189                                   (unsigned long *)(frame->retcode + 0));
 190                 err |= __put_user(0x5700,
 191                                   (unsigned short *)(frame->retcode + 4));
 192         }
 193         err |= __put_user(ret, &frame->pretcode);
 194
 195         if (err)
 196                 return -EFAULT;
 197
 198         /* Set up registers for signal handler */
 199         regs->sp  = (unsigned long)frame;
 200         regs->pc  = (unsigned long)ksig->ka.sa.sa_handler;
 201         regs->er0 = ksig->sig;
 202         regs->er1 = (unsigned long)&(frame->info);
 203         regs->er2 = (unsigned long)&frame->uc;
 204         regs->er5 = current->mm->start_data;    /* GOT base */
 205
 206         return 0;
 207 }
 208
 209 static void
 210 handle_restart(struct pt_regs *regs, struct k_sigaction *ka)
 211 {
 212         switch (regs->er0) {
 213         case -ERESTARTNOHAND:
 214                 if (!ka)
 215                         goto do_restart;
 216                 regs->er0 = -EINTR;
 217                 break;
 218         case -ERESTART_RESTARTBLOCK:
 219                 if (!ka) {
 220                         regs->er0 = __NR_restart_syscall;
 221                         regs->pc -= 2;
 222                 } else
 223                         regs->er0 = -EINTR;
 224                 break;
 225         case -ERESTARTSYS:
 226                 if (!(ka->sa.sa_flags & SA_RESTART)) {
 227                         regs->er0 = -EINTR;
 228                         break;
 229                 }
 230                 fallthrough;
 231         case -ERESTARTNOINTR:
 232 do_restart:
 233                 regs->er0 = regs->orig_er0;
 234                 regs->pc -= 2;
 235                 break;
 236         }
 237 }
 238
 239 /*
 240  * OK, we're invoking a handler
 241  */
 242 static void
 243 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 244 {
 245         sigset_t *oldset = sigmask_to_save();
 246         int ret;
 247         /* are we from a system call? */
 248         if (regs->orig_er0 >= 0)
 249                 handle_restart(regs, &ksig->ka);
 250
 251         ret = setup_rt_frame(ksig, oldset, regs);
 252
 253         signal_setup_done(ret, ksig, 0);
 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 static void do_signal(struct pt_regs *regs)
 262 {
 263         struct ksignal ksig;
 264
 265         current->thread.esp0 = (unsigned long) regs;
 266
 267         if (get_signal(&ksig)) {
 268                 /* Whee!  Actually deliver the signal.  */
 269                 handle_signal(&ksig, regs);
 270                 return;
 271         }
 272         /* Did we come from a system call? */
 273         if (regs->orig_er0 >= 0)
 274                 handle_restart(regs, NULL);
 275
 276         /* If there's no signal to deliver, we just restore the saved mask.  */
 277         restore_saved_sigmask();
 278 }
 279
 280 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
 281 {
 282         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
 283                 do_signal(regs);
 284
 285         if (thread_info_flags & _TIF_NOTIFY_RESUME)
 286                 tracehook_notify_resume(regs);
 287 }