LXR linux/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
  35struct 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
  45static int
  46restore_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
  89asmlinkage int
  90sys_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
 113badframe:
 114        force_sig(SIGSEGV, current);
 115        return 0;
 116}
 117
 118/*
 119 * Set up a signal frame.
 120 */
 121
 122static int
 123setup_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 */
 165static inline void __user *
 166get_sigframe(struct ksignal *ksig, unsigned long sp, size_t frame_size)
 167{
 168        return (void __user *)((sigsp(sp, ksig) - frame_size) & -8ul);
 169}
 170
 171static 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
 220static 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
 237static void
 238handle_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 */
 275static 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 */
 322void 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}
 337