arch/m32r/kernel/signal.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/arch/m32r/kernel/signal.c
   4  *
   5  *  Copyright (c) 2003  Hitoshi Yamamoto
   6  *
   7  *  Taken from i386 version.
   8  *  Copyright (C) 1991, 1992  Linus Torvalds
   9  *
  10  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
  11  *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
  12  */
  13
  14 #include <linux/sched.h>
  15 #include <linux/mm.h>
  16 #include <linux/smp.h>
  17 #include <linux/kernel.h>
  18 #include <linux/signal.h>
  19 #include <linux/errno.h>
  20 #include <linux/wait.h>
  21 #include <linux/unistd.h>
  22 #include <linux/stddef.h>
  23 #include <linux/personality.h>
  24 #include <linux/tracehook.h>
  25 #include <asm/cacheflush.h>
  26 #include <asm/ucontext.h>
  27 #include <linux/uaccess.h>
  28
  29 #define DEBUG_SIG 0
  30
  31 /*
  32  * Do a signal return; undo the signal stack.
  33  */
  34
  35 struct rt_sigframe
  36 {
  37         int sig;
  38         struct siginfo __user *pinfo;
  39         void __user *puc;
  40         struct siginfo info;
  41         struct ucontext uc;
  42 //      struct _fpstate fpstate;
  43 };
  44
  45 static int
  46 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
  47                    int *r0_p)
  48 {
  49         unsigned int err = 0;
  50
  51         /* Always make any pending restarted system calls return -EINTR */
  52         current->restart_block.fn = do_no_restart_syscall;
  53
  54 #define COPY(x)         err |= __get_user(regs->x, &sc->sc_##x)
  55         COPY(r4);
  56         COPY(r5);
  57         COPY(r6);
  58         COPY(pt_regs);
  59         /* COPY(r0); Skip r0 */
  60         COPY(r1);
  61         COPY(r2);
  62         COPY(r3);
  63         COPY(r7);
  64         COPY(r8);
  65         COPY(r9);
  66         COPY(r10);
  67         COPY(r11);
  68         COPY(r12);
  69         COPY(acc0h);
  70         COPY(acc0l);
  71         COPY(acc1h);            /* ISA_DSP_LEVEL2 only */
  72         COPY(acc1l);            /* ISA_DSP_LEVEL2 only */
  73         COPY(psw);
  74         COPY(bpc);
  75         COPY(bbpsw);
  76         COPY(bbpc);
  77         COPY(spu);
  78         COPY(fp);
  79         COPY(lr);
  80         COPY(spi);
  81 #undef COPY
  82
  83         regs->syscall_nr = -1;  /* disable syscall checks */
  84         err |= __get_user(*r0_p, &sc->sc_r0);
  85
  86         return err;
  87 }
  88
  89 asmlinkage int
  90 sys_rt_sigreturn(unsigned long r0, unsigned long r1,
  91                  unsigned long r2, unsigned long r3, unsigned long r4,
  92                  unsigned long r5, unsigned long r6, struct pt_regs *regs)
  93 {
  94         struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->spu;
  95         sigset_t set;
  96         int result;
  97
  98         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  99                 goto badframe;
 100         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 101                 goto badframe;
 102
 103         set_current_blocked(&set);
 104
 105         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &result))
 106                 goto badframe;
 107
 108         if (restore_altstack(&frame->uc.uc_stack))
 109                 goto badframe;
 110
 111         return result;
 112
 113 badframe:
 114         force_sig(SIGSEGV, current);
 115         return 0;
 116 }
 117
 118 /*
 119  * Set up a signal frame.
 120  */
 121
 122 static int
 123 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 124                  unsigned long mask)
 125 {
 126         int err = 0;
 127
 128 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
 129         COPY(r4);
 130         COPY(r5);
 131         COPY(r6);
 132         COPY(pt_regs);
 133         COPY(r0);
 134         COPY(r1);
 135         COPY(r2);
 136         COPY(r3);
 137         COPY(r7);
 138         COPY(r8);
 139         COPY(r9);
 140         COPY(r10);
 141         COPY(r11);
 142         COPY(r12);
 143         COPY(acc0h);
 144         COPY(acc0l);
 145         COPY(acc1h);            /* ISA_DSP_LEVEL2 only */
 146         COPY(acc1l);            /* ISA_DSP_LEVEL2 only */
 147         COPY(psw);
 148         COPY(bpc);
 149         COPY(bbpsw);
 150         COPY(bbpc);
 151         COPY(spu);
 152         COPY(fp);
 153         COPY(lr);
 154         COPY(spi);
 155 #undef COPY
 156
 157         err |= __put_user(mask, &sc->oldmask);
 158
 159         return err;
 160 }
 161
 162 /*
 163  * Determine which stack to use..
 164  */
 165 static inline void __user *
 166 get_sigframe(struct ksignal *ksig, unsigned long sp, size_t frame_size)
 167 {
 168         return (void __user *)((sigsp(sp, ksig) - frame_size) & -8ul);
 169 }
 170
 171 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
 172                           struct pt_regs *regs)
 173 {
 174         struct rt_sigframe __user *frame;
 175         int err = 0;
 176         int sig = ksig->sig;
 177
 178         frame = get_sigframe(ksig, regs->spu, sizeof(*frame));
 179
 180         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 181                 return -EFAULT;
 182
 183         err |= __put_user(sig, &frame->sig);
 184         if (err)
 185                 return -EFAULT;
 186
 187         err |= __put_user(&frame->info, &frame->pinfo);
 188         err |= __put_user(&frame->uc, &frame->puc);
 189         err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 190         if (err)
 191                 return -EFAULT;
 192
 193         /* Create the ucontext.  */
 194         err |= __put_user(0, &frame->uc.uc_flags);
 195         err |= __put_user(0, &frame->uc.uc_link);
 196         err |= __save_altstack(&frame->uc.uc_stack, regs->spu);
 197         err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
 198         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 199         if (err)
 200                 return -EFAULT;
 201
 202         /* Set up to return from userspace.  */
 203         regs->lr = (unsigned long)ksig->ka.sa.sa_restorer;
 204
 205         /* Set up registers for signal handler */
 206         regs->spu = (unsigned long)frame;
 207         regs->r0 = sig; /* Arg for signal handler */
 208         regs->r1 = (unsigned long)&frame->info;
 209         regs->r2 = (unsigned long)&frame->uc;
 210         regs->bpc = (unsigned long)ksig->ka.sa.sa_handler;
 211
 212 #if DEBUG_SIG
 213         printk("SIG deliver (%s:%d): sp=%p pc=%p\n",
 214                 current->comm, current->pid, frame, regs->pc);
 215 #endif
 216
 217         return 0;
 218 }
 219
 220 static int prev_insn(struct pt_regs *regs)
 221 {
 222         u16 inst;
 223         if (get_user(inst, (u16 __user *)(regs->bpc - 2)))
 224                 return -EFAULT;
 225         if ((inst & 0xfff0) == 0x10f0)  /* trap ? */
 226                 regs->bpc -= 2;
 227         else
 228                 regs->bpc -= 4;
 229         regs->syscall_nr = -1;
 230         return 0;
 231 }
 232
 233 /*
 234  * OK, we're invoking a handler
 235  */
 236
 237 static void
 238 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 239 {
 240         int ret;
 241
 242         /* Are we from a system call? */
 243         if (regs->syscall_nr >= 0) {
 244                 /* If so, check system call restarting.. */
 245                 switch (regs->r0) {
 246                         case -ERESTART_RESTARTBLOCK:
 247                         case -ERESTARTNOHAND:
 248                                 regs->r0 = -EINTR;
 249                                 break;
 250
 251                         case -ERESTARTSYS:
 252                                 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
 253                                         regs->r0 = -EINTR;
 254                                         break;
 255                                 }
 256                         /* fallthrough */
 257                         case -ERESTARTNOINTR:
 258                                 regs->r0 = regs->orig_r0;
 259                                 if (prev_insn(regs) < 0)
 260                                         return;
 261                 }
 262         }
 263
 264         /* Set up the stack frame */
 265         ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
 266
 267         signal_setup_done(ret, ksig, 0);
 268 }
 269
 270 /*
 271  * Note that 'init' is a special process: it doesn't get signals it doesn't
 272  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 273  * mistake.
 274  */
 275 static void do_signal(struct pt_regs *regs)
 276 {
 277         struct ksignal ksig;
 278
 279         /*
 280          * We want the common case to go fast, which
 281          * is why we may in certain cases get here from
 282          * kernel mode. Just return without doing anything
 283          * if so.
 284          */
 285         if (!user_mode(regs))
 286                 return;
 287
 288         if (get_signal(&ksig)) {
 289                 /* Re-enable any watchpoints before delivering the
 290                  * signal to user space. The processor register will
 291                  * have been cleared if the watchpoint triggered
 292                  * inside the kernel.
 293                  */
 294
 295                 /* Whee!  Actually deliver the signal.  */
 296                 handle_signal(&ksig, regs);
 297
 298                 return;
 299         }
 300
 301         /* Did we come from a system call? */
 302         if (regs->syscall_nr >= 0) {
 303                 /* Restart the system call - no handlers present */
 304                 if (regs->r0 == -ERESTARTNOHAND ||
 305                     regs->r0 == -ERESTARTSYS ||
 306                     regs->r0 == -ERESTARTNOINTR) {
 307                         regs->r0 = regs->orig_r0;
 308                         prev_insn(regs);
 309                 } else if (regs->r0 == -ERESTART_RESTARTBLOCK){
 310                         regs->r0 = regs->orig_r0;
 311                         regs->r7 = __NR_restart_syscall;
 312                         prev_insn(regs);
 313                 }
 314         }
 315         restore_saved_sigmask();
 316 }
 317
 318 /*
 319  * notification of userspace execution resumption
 320  * - triggered by current->work.notify_resume
 321  */
 322 void do_notify_resume(struct pt_regs *regs, __u32 thread_info_flags)
 323 {
 324         /* Pending single-step? */
 325         if (thread_info_flags & _TIF_SINGLESTEP)
 326                 clear_thread_flag(TIF_SINGLESTEP);
 327
 328         /* deal with pending signal delivery */
 329         if (thread_info_flags & _TIF_SIGPENDING)
 330                 do_signal(regs);
 331
 332         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 333                 clear_thread_flag(TIF_NOTIFY_RESUME);
 334                 tracehook_notify_resume(regs);
 335         }
 336 }