LXR linux/arch/nds32/kernel/signal.c

   1// SPDX-License-Identifier: GPL-2.0
   2// Copyright (C) 2005-2017 Andes Technology Corporation
   3
   4#include <linux/errno.h>
   5#include <linux/signal.h>
   6#include <linux/ptrace.h>
   7#include <linux/personality.h>
   8#include <linux/freezer.h>
   9#include <linux/tracehook.h>
  10#include <linux/uaccess.h>
  11
  12#include <asm/cacheflush.h>
  13#include <asm/ucontext.h>
  14#include <asm/unistd.h>
  15
  16#include <asm/ptrace.h>
  17#include <asm/vdso.h>
  18
  19struct rt_sigframe {
  20        struct siginfo info;
  21        struct ucontext uc;
  22};
  23
  24static int restore_sigframe(struct pt_regs *regs,
  25                            struct rt_sigframe __user * sf)
  26{
  27        sigset_t set;
  28        int err;
  29
  30        err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
  31        if (err == 0) {
  32                set_current_blocked(&set);
  33        }
  34
  35        __get_user_error(regs->uregs[0], &sf->uc.uc_mcontext.nds32_r0, err);
  36        __get_user_error(regs->uregs[1], &sf->uc.uc_mcontext.nds32_r1, err);
  37        __get_user_error(regs->uregs[2], &sf->uc.uc_mcontext.nds32_r2, err);
  38        __get_user_error(regs->uregs[3], &sf->uc.uc_mcontext.nds32_r3, err);
  39        __get_user_error(regs->uregs[4], &sf->uc.uc_mcontext.nds32_r4, err);
  40        __get_user_error(regs->uregs[5], &sf->uc.uc_mcontext.nds32_r5, err);
  41        __get_user_error(regs->uregs[6], &sf->uc.uc_mcontext.nds32_r6, err);
  42        __get_user_error(regs->uregs[7], &sf->uc.uc_mcontext.nds32_r7, err);
  43        __get_user_error(regs->uregs[8], &sf->uc.uc_mcontext.nds32_r8, err);
  44        __get_user_error(regs->uregs[9], &sf->uc.uc_mcontext.nds32_r9, err);
  45        __get_user_error(regs->uregs[10], &sf->uc.uc_mcontext.nds32_r10, err);
  46        __get_user_error(regs->uregs[11], &sf->uc.uc_mcontext.nds32_r11, err);
  47        __get_user_error(regs->uregs[12], &sf->uc.uc_mcontext.nds32_r12, err);
  48        __get_user_error(regs->uregs[13], &sf->uc.uc_mcontext.nds32_r13, err);
  49        __get_user_error(regs->uregs[14], &sf->uc.uc_mcontext.nds32_r14, err);
  50        __get_user_error(regs->uregs[15], &sf->uc.uc_mcontext.nds32_r15, err);
  51        __get_user_error(regs->uregs[16], &sf->uc.uc_mcontext.nds32_r16, err);
  52        __get_user_error(regs->uregs[17], &sf->uc.uc_mcontext.nds32_r17, err);
  53        __get_user_error(regs->uregs[18], &sf->uc.uc_mcontext.nds32_r18, err);
  54        __get_user_error(regs->uregs[19], &sf->uc.uc_mcontext.nds32_r19, err);
  55        __get_user_error(regs->uregs[20], &sf->uc.uc_mcontext.nds32_r20, err);
  56        __get_user_error(regs->uregs[21], &sf->uc.uc_mcontext.nds32_r21, err);
  57        __get_user_error(regs->uregs[22], &sf->uc.uc_mcontext.nds32_r22, err);
  58        __get_user_error(regs->uregs[23], &sf->uc.uc_mcontext.nds32_r23, err);
  59        __get_user_error(regs->uregs[24], &sf->uc.uc_mcontext.nds32_r24, err);
  60        __get_user_error(regs->uregs[25], &sf->uc.uc_mcontext.nds32_r25, err);
  61
  62        __get_user_error(regs->fp, &sf->uc.uc_mcontext.nds32_fp, err);
  63        __get_user_error(regs->gp, &sf->uc.uc_mcontext.nds32_gp, err);
  64        __get_user_error(regs->lp, &sf->uc.uc_mcontext.nds32_lp, err);
  65        __get_user_error(regs->sp, &sf->uc.uc_mcontext.nds32_sp, err);
  66        __get_user_error(regs->ipc, &sf->uc.uc_mcontext.nds32_ipc, err);
  67#if defined(CONFIG_HWZOL)
  68        __get_user_error(regs->lc, &sf->uc.uc_mcontext.zol.nds32_lc, err);
  69        __get_user_error(regs->le, &sf->uc.uc_mcontext.zol.nds32_le, err);
  70        __get_user_error(regs->lb, &sf->uc.uc_mcontext.zol.nds32_lb, err);
  71#endif
  72
  73        /*
  74         * Avoid sys_rt_sigreturn() restarting.
  75         */
  76        forget_syscall(regs);
  77        return err;
  78}
  79
  80asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
  81{
  82        struct rt_sigframe __user *frame;
  83
  84        /* Always make any pending restarted system calls return -EINTR */
  85        current->restart_block.fn = do_no_restart_syscall;
  86
  87        /*
  88         * Since we stacked the signal on a 64-bit boundary,
  89         * then 'sp' should be two-word aligned here.  If it's
  90         * not, then the user is trying to mess with us.
  91         */
  92        if (regs->sp & 7)
  93                goto badframe;
  94
  95        frame = (struct rt_sigframe __user *)regs->sp;
  96
  97        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  98                goto badframe;
  99
 100        if (restore_sigframe(regs, frame))
 101                goto badframe;
 102
 103        if (restore_altstack(&frame->uc.uc_stack))
 104                goto badframe;
 105
 106        return regs->uregs[0];
 107
 108badframe:
 109        force_sig(SIGSEGV, current);
 110        return 0;
 111}
 112
 113static int
 114setup_sigframe(struct rt_sigframe __user * sf, struct pt_regs *regs,
 115               sigset_t * set)
 116{
 117        int err = 0;
 118
 119        __put_user_error(regs->uregs[0], &sf->uc.uc_mcontext.nds32_r0, err);
 120        __put_user_error(regs->uregs[1], &sf->uc.uc_mcontext.nds32_r1, err);
 121        __put_user_error(regs->uregs[2], &sf->uc.uc_mcontext.nds32_r2, err);
 122        __put_user_error(regs->uregs[3], &sf->uc.uc_mcontext.nds32_r3, err);
 123        __put_user_error(regs->uregs[4], &sf->uc.uc_mcontext.nds32_r4, err);
 124        __put_user_error(regs->uregs[5], &sf->uc.uc_mcontext.nds32_r5, err);
 125        __put_user_error(regs->uregs[6], &sf->uc.uc_mcontext.nds32_r6, err);
 126        __put_user_error(regs->uregs[7], &sf->uc.uc_mcontext.nds32_r7, err);
 127        __put_user_error(regs->uregs[8], &sf->uc.uc_mcontext.nds32_r8, err);
 128        __put_user_error(regs->uregs[9], &sf->uc.uc_mcontext.nds32_r9, err);
 129        __put_user_error(regs->uregs[10], &sf->uc.uc_mcontext.nds32_r10, err);
 130        __put_user_error(regs->uregs[11], &sf->uc.uc_mcontext.nds32_r11, err);
 131        __put_user_error(regs->uregs[12], &sf->uc.uc_mcontext.nds32_r12, err);
 132        __put_user_error(regs->uregs[13], &sf->uc.uc_mcontext.nds32_r13, err);
 133        __put_user_error(regs->uregs[14], &sf->uc.uc_mcontext.nds32_r14, err);
 134        __put_user_error(regs->uregs[15], &sf->uc.uc_mcontext.nds32_r15, err);
 135        __put_user_error(regs->uregs[16], &sf->uc.uc_mcontext.nds32_r16, err);
 136        __put_user_error(regs->uregs[17], &sf->uc.uc_mcontext.nds32_r17, err);
 137        __put_user_error(regs->uregs[18], &sf->uc.uc_mcontext.nds32_r18, err);
 138        __put_user_error(regs->uregs[19], &sf->uc.uc_mcontext.nds32_r19, err);
 139        __put_user_error(regs->uregs[20], &sf->uc.uc_mcontext.nds32_r20, err);
 140
 141        __put_user_error(regs->uregs[21], &sf->uc.uc_mcontext.nds32_r21, err);
 142        __put_user_error(regs->uregs[22], &sf->uc.uc_mcontext.nds32_r22, err);
 143        __put_user_error(regs->uregs[23], &sf->uc.uc_mcontext.nds32_r23, err);
 144        __put_user_error(regs->uregs[24], &sf->uc.uc_mcontext.nds32_r24, err);
 145        __put_user_error(regs->uregs[25], &sf->uc.uc_mcontext.nds32_r25, err);
 146        __put_user_error(regs->fp, &sf->uc.uc_mcontext.nds32_fp, err);
 147        __put_user_error(regs->gp, &sf->uc.uc_mcontext.nds32_gp, err);
 148        __put_user_error(regs->lp, &sf->uc.uc_mcontext.nds32_lp, err);
 149        __put_user_error(regs->sp, &sf->uc.uc_mcontext.nds32_sp, err);
 150        __put_user_error(regs->ipc, &sf->uc.uc_mcontext.nds32_ipc, err);
 151#if defined(CONFIG_HWZOL)
 152        __put_user_error(regs->lc, &sf->uc.uc_mcontext.zol.nds32_lc, err);
 153        __put_user_error(regs->le, &sf->uc.uc_mcontext.zol.nds32_le, err);
 154        __put_user_error(regs->lb, &sf->uc.uc_mcontext.zol.nds32_lb, err);
 155#endif
 156
 157        __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no,
 158                         err);
 159        __put_user_error(current->thread.error_code,
 160                         &sf->uc.uc_mcontext.error_code, err);
 161        __put_user_error(current->thread.address,
 162                         &sf->uc.uc_mcontext.fault_address, err);
 163        __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
 164
 165        err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
 166
 167        return err;
 168}
 169
 170static inline void __user *get_sigframe(struct ksignal *ksig,
 171                                        struct pt_regs *regs, int framesize)
 172{
 173        unsigned long sp;
 174
 175        /* Default to using normal stack */
 176        sp = regs->sp;
 177
 178        /*
 179         * If we are on the alternate signal stack and would overflow it, don't.
 180         * Return an always-bogus address instead so we will die with SIGSEGV.
 181         */
 182        if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
 183                return (void __user __force *)(-1UL);
 184
 185        /* This is the X/Open sanctioned signal stack switching. */
 186        sp = (sigsp(sp, ksig) - framesize);
 187
 188        /*
 189         * nds32 mandates 8-byte alignment
 190         */
 191        sp &= ~0x7UL;
 192
 193        return (void __user *)sp;
 194}
 195
 196static int
 197setup_return(struct pt_regs *regs, struct ksignal *ksig, void __user * frame)
 198{
 199        unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
 200        unsigned long retcode;
 201
 202        retcode = VDSO_SYMBOL(current->mm->context.vdso, rt_sigtramp);
 203        regs->uregs[0] = ksig->sig;
 204        regs->sp = (unsigned long)frame;
 205        regs->lp = retcode;
 206        regs->ipc = handler;
 207
 208        return 0;
 209}
 210
 211static int
 212setup_rt_frame(struct ksignal *ksig, sigset_t * set, struct pt_regs *regs)
 213{
 214        struct rt_sigframe __user *frame =
 215            get_sigframe(ksig, regs, sizeof(*frame));
 216        int err = 0;
 217
 218        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 219                return -EFAULT;
 220
 221        __put_user_error(0, &frame->uc.uc_flags, err);
 222        __put_user_error(NULL, &frame->uc.uc_link, err);
 223
 224        err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
 225        err |= setup_sigframe(frame, regs, set);
 226        if (err == 0) {
 227                setup_return(regs, ksig, frame);
 228                if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
 229                        err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 230                        regs->uregs[1] = (unsigned long)&frame->info;
 231                        regs->uregs[2] = (unsigned long)&frame->uc;
 232                }
 233        }
 234        return err;
 235}
 236
 237/*
 238 * OK, we're invoking a handler
 239 */
 240static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 241{
 242        int ret;
 243        sigset_t *oldset = sigmask_to_save();
 244
 245        if (in_syscall(regs)) {
 246                /* Avoid additional syscall restarting via ret_slow_syscall. */
 247                forget_syscall(regs);
 248
 249                switch (regs->uregs[0]) {
 250                case -ERESTART_RESTARTBLOCK:
 251                case -ERESTARTNOHAND:
 252                        regs->uregs[0] = -EINTR;
 253                        break;
 254                case -ERESTARTSYS:
 255                        if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
 256                                regs->uregs[0] = -EINTR;
 257                                break;
 258                        }
 259                case -ERESTARTNOINTR:
 260                        regs->uregs[0] = regs->orig_r0;
 261                        regs->ipc -= 4;
 262                        break;
 263                }
 264        }
 265        /*
 266         * Set up the stack frame
 267         */
 268        ret = setup_rt_frame(ksig, oldset, regs);
 269
 270        signal_setup_done(ret, ksig, 0);
 271}
 272
 273/*
 274 * Note that 'init' is a special process: it doesn't get signals it doesn't
 275 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 276 * mistake.
 277 *
 278 * Note that we go through the signals twice: once to check the signals that
 279 * the kernel can handle, and then we build all the user-level signal handling
 280 * stack-frames in one go after that.
 281 */
 282static void do_signal(struct pt_regs *regs)
 283{
 284        struct ksignal ksig;
 285
 286        if (get_signal(&ksig)) {
 287                handle_signal(&ksig, regs);
 288                return;
 289        }
 290
 291        /*
 292         * If we were from a system call, check for system call restarting...
 293         */
 294        if (in_syscall(regs)) {
 295                /* Restart the system call - no handlers present */
 296
 297                /* Avoid additional syscall restarting via ret_slow_syscall. */
 298                forget_syscall(regs);
 299
 300                switch (regs->uregs[0]) {
 301                case -ERESTART_RESTARTBLOCK:
 302                        regs->uregs[15] = __NR_restart_syscall;
 303                case -ERESTARTNOHAND:
 304                case -ERESTARTSYS:
 305                case -ERESTARTNOINTR:
 306                        regs->uregs[0] = regs->orig_r0;
 307                        regs->ipc -= 0x4;
 308                        break;
 309                }
 310        }
 311        restore_saved_sigmask();
 312}
 313
 314asmlinkage void
 315do_notify_resume(struct pt_regs *regs, unsigned int thread_flags)
 316{
 317        if (thread_flags & _TIF_SIGPENDING)
 318                do_signal(regs);
 319
 320        if (thread_flags & _TIF_NOTIFY_RESUME) {
 321                clear_thread_flag(TIF_NOTIFY_RESUME);
 322                tracehook_notify_resume(regs);
 323        }
 324}
 325