arch/arm64/kernel/signal32.c

   1 /*
   2  * Based on arch/arm/kernel/signal.c
   3  *
   4  * Copyright (C) 1995-2009 Russell King
   5  * Copyright (C) 2012 ARM Ltd.
   6  * Modified by Will Deacon <will.deacon@arm.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <linux/compat.h>
  22 #include <linux/signal.h>
  23 #include <linux/syscalls.h>
  24 #include <linux/ratelimit.h>
  25
  26 #include <asm/fpsimd.h>
  27 #include <asm/signal32.h>
  28 #include <asm/uaccess.h>
  29 #include <asm/unistd32.h>
  30
  31 struct compat_sigaction {
  32         compat_uptr_t                   sa_handler;
  33         compat_ulong_t                  sa_flags;
  34         compat_uptr_t                   sa_restorer;
  35         compat_sigset_t                 sa_mask;
  36 };
  37
  38 struct compat_old_sigaction {
  39         compat_uptr_t                   sa_handler;
  40         compat_old_sigset_t             sa_mask;
  41         compat_ulong_t                  sa_flags;
  42         compat_uptr_t                   sa_restorer;
  43 };
  44
  45 typedef struct compat_sigaltstack {
  46         compat_uptr_t                   ss_sp;
  47         int                             ss_flags;
  48         compat_size_t                   ss_size;
  49 } compat_stack_t;
  50
  51 struct compat_sigcontext {
  52         /* We always set these two fields to 0 */
  53         compat_ulong_t                  trap_no;
  54         compat_ulong_t                  error_code;
  55
  56         compat_ulong_t                  oldmask;
  57         compat_ulong_t                  arm_r0;
  58         compat_ulong_t                  arm_r1;
  59         compat_ulong_t                  arm_r2;
  60         compat_ulong_t                  arm_r3;
  61         compat_ulong_t                  arm_r4;
  62         compat_ulong_t                  arm_r5;
  63         compat_ulong_t                  arm_r6;
  64         compat_ulong_t                  arm_r7;
  65         compat_ulong_t                  arm_r8;
  66         compat_ulong_t                  arm_r9;
  67         compat_ulong_t                  arm_r10;
  68         compat_ulong_t                  arm_fp;
  69         compat_ulong_t                  arm_ip;
  70         compat_ulong_t                  arm_sp;
  71         compat_ulong_t                  arm_lr;
  72         compat_ulong_t                  arm_pc;
  73         compat_ulong_t                  arm_cpsr;
  74         compat_ulong_t                  fault_address;
  75 };
  76
  77 struct compat_ucontext {
  78         compat_ulong_t                  uc_flags;
  79         struct compat_ucontext          *uc_link;
  80         compat_stack_t                  uc_stack;
  81         struct compat_sigcontext        uc_mcontext;
  82         compat_sigset_t                 uc_sigmask;
  83         int             __unused[32 - (sizeof (compat_sigset_t) / sizeof (int))];
  84         compat_ulong_t  uc_regspace[128] __attribute__((__aligned__(8)));
  85 };
  86
  87 struct compat_vfp_sigframe {
  88         compat_ulong_t  magic;
  89         compat_ulong_t  size;
  90         struct compat_user_vfp {
  91                 compat_u64      fpregs[32];
  92                 compat_ulong_t  fpscr;
  93         } ufp;
  94         struct compat_user_vfp_exc {
  95                 compat_ulong_t  fpexc;
  96                 compat_ulong_t  fpinst;
  97                 compat_ulong_t  fpinst2;
  98         } ufp_exc;
  99 } __attribute__((__aligned__(8)));
 100
 101 #define VFP_MAGIC               0x56465001
 102 #define VFP_STORAGE_SIZE        sizeof(struct compat_vfp_sigframe)
 103
 104 struct compat_aux_sigframe {
 105         struct compat_vfp_sigframe      vfp;
 106
 107         /* Something that isn't a valid magic number for any coprocessor.  */
 108         unsigned long                   end_magic;
 109 } __attribute__((__aligned__(8)));
 110
 111 struct compat_sigframe {
 112         struct compat_ucontext  uc;
 113         compat_ulong_t          retcode[2];
 114 };
 115
 116 struct compat_rt_sigframe {
 117         struct compat_siginfo info;
 118         struct compat_sigframe sig;
 119 };
 120
 121 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 122
 123 /*
 124  * For ARM syscalls, the syscall number has to be loaded into r7.
 125  * We do not support an OABI userspace.
 126  */
 127 #define MOV_R7_NR_SIGRETURN     (0xe3a07000 | __NR_compat_sigreturn)
 128 #define SVC_SYS_SIGRETURN       (0xef000000 | __NR_compat_sigreturn)
 129 #define MOV_R7_NR_RT_SIGRETURN  (0xe3a07000 | __NR_compat_rt_sigreturn)
 130 #define SVC_SYS_RT_SIGRETURN    (0xef000000 | __NR_compat_rt_sigreturn)
 131
 132 /*
 133  * For Thumb syscalls, we also pass the syscall number via r7. We therefore
 134  * need two 16-bit instructions.
 135  */
 136 #define SVC_THUMB_SIGRETURN     (((0xdf00 | __NR_compat_sigreturn) << 16) | \
 137                                    0x2700 | __NR_compat_sigreturn)
 138 #define SVC_THUMB_RT_SIGRETURN  (((0xdf00 | __NR_compat_rt_sigreturn) << 16) | \
 139                                    0x2700 | __NR_compat_rt_sigreturn)
 140
 141 const compat_ulong_t aarch32_sigret_code[6] = {
 142         /*
 143          * AArch32 sigreturn code.
 144          * We don't construct an OABI SWI - instead we just set the imm24 field
 145          * to the EABI syscall number so that we create a sane disassembly.
 146          */
 147         MOV_R7_NR_SIGRETURN,    SVC_SYS_SIGRETURN,    SVC_THUMB_SIGRETURN,
 148         MOV_R7_NR_RT_SIGRETURN, SVC_SYS_RT_SIGRETURN, SVC_THUMB_RT_SIGRETURN,
 149 };
 150
 151 static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set)
 152 {
 153         compat_sigset_t cset;
 154
 155         cset.sig[0] = set->sig[0] & 0xffffffffull;
 156         cset.sig[1] = set->sig[0] >> 32;
 157
 158         return copy_to_user(uset, &cset, sizeof(*uset));
 159 }
 160
 161 static inline int get_sigset_t(sigset_t *set,
 162                                const compat_sigset_t __user *uset)
 163 {
 164         compat_sigset_t s32;
 165
 166         if (copy_from_user(&s32, uset, sizeof(*uset)))
 167                 return -EFAULT;
 168
 169         set->sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32);
 170         return 0;
 171 }
 172
 173 int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
 174 {
 175         int err;
 176
 177         if (!access_ok(VERIFY_WRITE, to, sizeof(*to)))
 178                 return -EFAULT;
 179
 180         /* If you change siginfo_t structure, please be sure
 181          * this code is fixed accordingly.
 182          * It should never copy any pad contained in the structure
 183          * to avoid security leaks, but must copy the generic
 184          * 3 ints plus the relevant union member.
 185          * This routine must convert siginfo from 64bit to 32bit as well
 186          * at the same time.
 187          */
 188         err = __put_user(from->si_signo, &to->si_signo);
 189         err |= __put_user(from->si_errno, &to->si_errno);
 190         err |= __put_user((short)from->si_code, &to->si_code);
 191         if (from->si_code < 0)
 192                 err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad,
 193                                       SI_PAD_SIZE);
 194         else switch (from->si_code & __SI_MASK) {
 195         case __SI_KILL:
 196                 err |= __put_user(from->si_pid, &to->si_pid);
 197                 err |= __put_user(from->si_uid, &to->si_uid);
 198                 break;
 199         case __SI_TIMER:
 200                  err |= __put_user(from->si_tid, &to->si_tid);
 201                  err |= __put_user(from->si_overrun, &to->si_overrun);
 202                  err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr,
 203                                    &to->si_ptr);
 204                 break;
 205         case __SI_POLL:
 206                 err |= __put_user(from->si_band, &to->si_band);
 207                 err |= __put_user(from->si_fd, &to->si_fd);
 208                 break;
 209         case __SI_FAULT:
 210                 err |= __put_user((compat_uptr_t)(unsigned long)from->si_addr,
 211                                   &to->si_addr);
 212 #ifdef BUS_MCEERR_AO
 213                 /*
 214                  * Other callers might not initialize the si_lsb field,
 215                  * so check explicitely for the right codes here.
 216                  */
 217                 if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
 218                         err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
 219 #endif
 220                 break;
 221         case __SI_CHLD:
 222                 err |= __put_user(from->si_pid, &to->si_pid);
 223                 err |= __put_user(from->si_uid, &to->si_uid);
 224                 err |= __put_user(from->si_status, &to->si_status);
 225                 err |= __put_user(from->si_utime, &to->si_utime);
 226                 err |= __put_user(from->si_stime, &to->si_stime);
 227                 break;
 228         case __SI_RT: /* This is not generated by the kernel as of now. */
 229         case __SI_MESGQ: /* But this is */
 230                 err |= __put_user(from->si_pid, &to->si_pid);
 231                 err |= __put_user(from->si_uid, &to->si_uid);
 232                 err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, &to->si_ptr);
 233                 break;
 234         default: /* this is just in case for now ... */
 235                 err |= __put_user(from->si_pid, &to->si_pid);
 236                 err |= __put_user(from->si_uid, &to->si_uid);
 237                 break;
 238         }
 239         return err;
 240 }
 241
 242 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
 243 {
 244         memset(to, 0, sizeof *to);
 245
 246         if (copy_from_user(to, from, __ARCH_SI_PREAMBLE_SIZE) ||
 247             copy_from_user(to->_sifields._pad,
 248                            from->_sifields._pad, SI_PAD_SIZE))
 249                 return -EFAULT;
 250
 251         return 0;
 252 }
 253
 254 /*
 255  * VFP save/restore code.
 256  */
 257 static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame)
 258 {
 259         struct fpsimd_state *fpsimd = &current->thread.fpsimd_state;
 260         compat_ulong_t magic = VFP_MAGIC;
 261         compat_ulong_t size = VFP_STORAGE_SIZE;
 262         compat_ulong_t fpscr, fpexc;
 263         int err = 0;
 264
 265         /*
 266          * Save the hardware registers to the fpsimd_state structure.
 267          * Note that this also saves V16-31, which aren't visible
 268          * in AArch32.
 269          */
 270         fpsimd_save_state(fpsimd);
 271
 272         /* Place structure header on the stack */
 273         __put_user_error(magic, &frame->magic, err);
 274         __put_user_error(size, &frame->size, err);
 275
 276         /*
 277          * Now copy the FP registers. Since the registers are packed,
 278          * we can copy the prefix we want (V0-V15) as it is.
 279          * FIXME: Won't work if big endian.
 280          */
 281         err |= __copy_to_user(&frame->ufp.fpregs, fpsimd->vregs,
 282                               sizeof(frame->ufp.fpregs));
 283
 284         /* Create an AArch32 fpscr from the fpsr and the fpcr. */
 285         fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) |
 286                 (fpsimd->fpcr & VFP_FPSCR_CTRL_MASK);
 287         __put_user_error(fpscr, &frame->ufp.fpscr, err);
 288
 289         /*
 290          * The exception register aren't available so we fake up a
 291          * basic FPEXC and zero everything else.
 292          */
 293         fpexc = (1 << 30);
 294         __put_user_error(fpexc, &frame->ufp_exc.fpexc, err);
 295         __put_user_error(0, &frame->ufp_exc.fpinst, err);
 296         __put_user_error(0, &frame->ufp_exc.fpinst2, err);
 297
 298         return err ? -EFAULT : 0;
 299 }
 300
 301 static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame)
 302 {
 303         struct fpsimd_state fpsimd;
 304         compat_ulong_t magic = VFP_MAGIC;
 305         compat_ulong_t size = VFP_STORAGE_SIZE;
 306         compat_ulong_t fpscr;
 307         int err = 0;
 308
 309         __get_user_error(magic, &frame->magic, err);
 310         __get_user_error(size, &frame->size, err);
 311
 312         if (err)
 313                 return -EFAULT;
 314         if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
 315                 return -EINVAL;
 316
 317         /*
 318          * Copy the FP registers into the start of the fpsimd_state.
 319          * FIXME: Won't work if big endian.
 320          */
 321         err |= __copy_from_user(fpsimd.vregs, frame->ufp.fpregs,
 322                                 sizeof(frame->ufp.fpregs));
 323
 324         /* Extract the fpsr and the fpcr from the fpscr */
 325         __get_user_error(fpscr, &frame->ufp.fpscr, err);
 326         fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK;
 327         fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
 328
 329         /*
 330          * We don't need to touch the exception register, so
 331          * reload the hardware state.
 332          */
 333         if (!err) {
 334                 preempt_disable();
 335                 fpsimd_load_state(&fpsimd);
 336                 preempt_enable();
 337         }
 338
 339         return err ? -EFAULT : 0;
 340 }
 341
 342 /*
 343  * atomically swap in the new signal mask, and wait for a signal.
 344  */
 345 asmlinkage int compat_sys_sigsuspend(int restart, compat_ulong_t oldmask,
 346                                      compat_old_sigset_t mask)
 347 {
 348         sigset_t blocked;
 349
 350         siginitset(&current->blocked, mask);
 351         return sigsuspend(&blocked);
 352 }
 353
 354 asmlinkage int compat_sys_sigaction(int sig,
 355                                     const struct compat_old_sigaction __user *act,
 356                                     struct compat_old_sigaction __user *oact)
 357 {
 358         struct k_sigaction new_ka, old_ka;
 359         int ret;
 360         compat_old_sigset_t mask;
 361         compat_uptr_t handler, restorer;
 362
 363         if (act) {
 364                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
 365                     __get_user(handler, &act->sa_handler) ||
 366                     __get_user(restorer, &act->sa_restorer) ||
 367                     __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
 368                     __get_user(mask, &act->sa_mask))
 369                         return -EFAULT;
 370
 371                 new_ka.sa.sa_handler = compat_ptr(handler);
 372                 new_ka.sa.sa_restorer = compat_ptr(restorer);
 373                 siginitset(&new_ka.sa.sa_mask, mask);
 374         }
 375
 376         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 377
 378         if (!ret && oact) {
 379                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 380                     __put_user(ptr_to_compat(old_ka.sa.sa_handler),
 381                                &oact->sa_handler) ||
 382                     __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
 383                                &oact->sa_restorer) ||
 384                     __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
 385                     __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
 386                         return -EFAULT;
 387         }
 388
 389         return ret;
 390 }
 391
 392 asmlinkage int compat_sys_rt_sigaction(int sig,
 393                                        const struct compat_sigaction __user *act,
 394                                        struct compat_sigaction __user *oact,
 395                                        compat_size_t sigsetsize)
 396 {
 397         struct k_sigaction new_ka, old_ka;
 398         int ret;
 399
 400         /* XXX: Don't preclude handling different sized sigset_t's.  */
 401         if (sigsetsize != sizeof(compat_sigset_t))
 402                 return -EINVAL;
 403
 404         if (act) {
 405                 compat_uptr_t handler, restorer;
 406
 407                 ret = get_user(handler, &act->sa_handler);
 408                 new_ka.sa.sa_handler = compat_ptr(handler);
 409                 ret |= get_user(restorer, &act->sa_restorer);
 410                 new_ka.sa.sa_restorer = compat_ptr(restorer);
 411                 ret |= get_sigset_t(&new_ka.sa.sa_mask, &act->sa_mask);
 412                 ret |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 413                 if (ret)
 414                         return -EFAULT;
 415         }
 416
 417         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 418         if (!ret && oact) {
 419                 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), &oact->sa_handler);
 420                 ret |= put_sigset_t(&oact->sa_mask, &old_ka.sa.sa_mask);
 421                 ret |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 422         }
 423         return ret;
 424 }
 425
 426 int compat_do_sigaltstack(compat_uptr_t compat_uss, compat_uptr_t compat_uoss,
 427                           compat_ulong_t sp)
 428 {
 429         compat_stack_t __user *newstack = compat_ptr(compat_uss);
 430         compat_stack_t __user *oldstack = compat_ptr(compat_uoss);
 431         compat_uptr_t ss_sp;
 432         int ret;
 433         mm_segment_t old_fs;
 434         stack_t uss, uoss;
 435
 436         /* Marshall the compat new stack into a stack_t */
 437         if (newstack) {
 438                 if (get_user(ss_sp, &newstack->ss_sp) ||
 439                     __get_user(uss.ss_flags, &newstack->ss_flags) ||
 440                     __get_user(uss.ss_size, &newstack->ss_size))
 441                         return -EFAULT;
 442                 uss.ss_sp = compat_ptr(ss_sp);
 443         }
 444
 445         old_fs = get_fs();
 446         set_fs(KERNEL_DS);
 447         /* The __user pointer casts are valid because of the set_fs() */
 448         ret = do_sigaltstack(
 449                 newstack ? (stack_t __user *) &uss : NULL,
 450                 oldstack ? (stack_t __user *) &uoss : NULL,
 451                 (unsigned long)sp);
 452         set_fs(old_fs);
 453
 454         /* Convert the old stack_t into a compat stack. */
 455         if (!ret && oldstack &&
 456                 (put_user(ptr_to_compat(uoss.ss_sp), &oldstack->ss_sp) ||
 457                  __put_user(uoss.ss_flags, &oldstack->ss_flags) ||
 458                  __put_user(uoss.ss_size, &oldstack->ss_size)))
 459                 return -EFAULT;
 460         return ret;
 461 }
 462
 463 static int compat_restore_sigframe(struct pt_regs *regs,
 464                                    struct compat_sigframe __user *sf)
 465 {
 466         int err;
 467         sigset_t set;
 468         struct compat_aux_sigframe __user *aux;
 469
 470         err = get_sigset_t(&set, &sf->uc.uc_sigmask);
 471         if (err == 0) {
 472                 sigdelsetmask(&set, ~_BLOCKABLE);
 473                 set_current_blocked(&set);
 474         }
 475
 476         __get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
 477         __get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err);
 478         __get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err);
 479         __get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err);
 480         __get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err);
 481         __get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err);
 482         __get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err);
 483         __get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err);
 484         __get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err);
 485         __get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err);
 486         __get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err);
 487         __get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err);
 488         __get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err);
 489         __get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
 490         __get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
 491         __get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
 492         __get_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err);
 493
 494         /*
 495          * Avoid compat_sys_sigreturn() restarting.
 496          */
 497         regs->syscallno = ~0UL;
 498
 499         err |= !valid_user_regs(&regs->user_regs);
 500
 501         aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
 502         if (err == 0)
 503                 err |= compat_restore_vfp_context(&aux->vfp);
 504
 505         return err;
 506 }
 507
 508 asmlinkage int compat_sys_sigreturn(struct pt_regs *regs)
 509 {
 510         struct compat_sigframe __user *frame;
 511
 512         /* Always make any pending restarted system calls return -EINTR */
 513         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 514
 515         /*
 516          * Since we stacked the signal on a 64-bit boundary,
 517          * then 'sp' should be word aligned here.  If it's
 518          * not, then the user is trying to mess with us.
 519          */
 520         if (regs->compat_sp & 7)
 521                 goto badframe;
 522
 523         frame = (struct compat_sigframe __user *)regs->compat_sp;
 524
 525         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 526                 goto badframe;
 527
 528         if (compat_restore_sigframe(regs, frame))
 529                 goto badframe;
 530
 531         return regs->regs[0];
 532
 533 badframe:
 534         if (show_unhandled_signals)
 535                 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n",
 536                                     current->comm, task_pid_nr(current), __func__,
 537                                     regs->pc, regs->sp);
 538         force_sig(SIGSEGV, current);
 539         return 0;
 540 }
 541
 542 asmlinkage int compat_sys_rt_sigreturn(struct pt_regs *regs)
 543 {
 544         struct compat_rt_sigframe __user *frame;
 545
 546         /* Always make any pending restarted system calls return -EINTR */
 547         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 548
 549         /*
 550          * Since we stacked the signal on a 64-bit boundary,
 551          * then 'sp' should be word aligned here.  If it's
 552          * not, then the user is trying to mess with us.
 553          */
 554         if (regs->compat_sp & 7)
 555                 goto badframe;
 556
 557         frame = (struct compat_rt_sigframe __user *)regs->compat_sp;
 558
 559         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 560                 goto badframe;
 561
 562         if (compat_restore_sigframe(regs, &frame->sig))
 563                 goto badframe;
 564
 565         if (compat_do_sigaltstack(ptr_to_compat(&frame->sig.uc.uc_stack),
 566                                  ptr_to_compat((void __user *)NULL),
 567                                  regs->compat_sp) == -EFAULT)
 568                 goto badframe;
 569
 570         return regs->regs[0];
 571
 572 badframe:
 573         if (show_unhandled_signals)
 574                 pr_info_ratelimited("%s[%d]: bad frame in %s: pc=%08llx sp=%08llx\n",
 575                                     current->comm, task_pid_nr(current), __func__,
 576                                     regs->pc, regs->sp);
 577         force_sig(SIGSEGV, current);
 578         return 0;
 579 }
 580
 581 static void __user *compat_get_sigframe(struct k_sigaction *ka,
 582                                         struct pt_regs *regs,
 583                                         int framesize)
 584 {
 585         compat_ulong_t sp = regs->compat_sp;
 586         void __user *frame;
 587
 588         /*
 589          * This is the X/Open sanctioned signal stack switching.
 590          */
 591         if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
 592                 sp = current->sas_ss_sp + current->sas_ss_size;
 593
 594         /*
 595          * ATPCS B01 mandates 8-byte alignment
 596          */
 597         frame = compat_ptr((compat_uptr_t)((sp - framesize) & ~7));
 598
 599         /*
 600          * Check that we can actually write to the signal frame.
 601          */
 602         if (!access_ok(VERIFY_WRITE, frame, framesize))
 603                 frame = NULL;
 604
 605         return frame;
 606 }
 607
 608 static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 609                                 compat_ulong_t __user *rc, void __user *frame,
 610                                 int usig)
 611 {
 612         compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler);
 613         compat_ulong_t retcode;
 614         compat_ulong_t spsr = regs->pstate & ~PSR_f;
 615         int thumb;
 616
 617         /* Check if the handler is written for ARM or Thumb */
 618         thumb = handler & 1;
 619
 620         if (thumb) {
 621                 spsr |= COMPAT_PSR_T_BIT;
 622                 spsr &= ~COMPAT_PSR_IT_MASK;
 623         } else {
 624                 spsr &= ~COMPAT_PSR_T_BIT;
 625         }
 626
 627         if (ka->sa.sa_flags & SA_RESTORER) {
 628                 retcode = ptr_to_compat(ka->sa.sa_restorer);
 629         } else {
 630                 /* Set up sigreturn pointer */
 631                 unsigned int idx = thumb << 1;
 632
 633                 if (ka->sa.sa_flags & SA_SIGINFO)
 634                         idx += 3;
 635
 636                 retcode = AARCH32_VECTORS_BASE +
 637                           AARCH32_KERN_SIGRET_CODE_OFFSET +
 638                           (idx << 2) + thumb;
 639         }
 640
 641         regs->regs[0]   = usig;
 642         regs->compat_sp = ptr_to_compat(frame);
 643         regs->compat_lr = retcode;
 644         regs->pc        = handler;
 645         regs->pstate    = spsr;
 646 }
 647
 648 static int compat_setup_sigframe(struct compat_sigframe __user *sf,
 649                                  struct pt_regs *regs, sigset_t *set)
 650 {
 651         struct compat_aux_sigframe __user *aux;
 652         int err = 0;
 653
 654         __put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err);
 655         __put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err);
 656         __put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err);
 657         __put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err);
 658         __put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err);
 659         __put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err);
 660         __put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err);
 661         __put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err);
 662         __put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err);
 663         __put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err);
 664         __put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err);
 665         __put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err);
 666         __put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err);
 667         __put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err);
 668         __put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err);
 669         __put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err);
 670         __put_user_error(regs->pstate, &sf->uc.uc_mcontext.arm_cpsr, err);
 671
 672         __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err);
 673         __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.error_code, err);
 674         __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err);
 675         __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
 676
 677         err |= put_sigset_t(&sf->uc.uc_sigmask, set);
 678
 679         aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace;
 680
 681         if (err == 0)
 682                 err |= compat_preserve_vfp_context(&aux->vfp);
 683         __put_user_error(0, &aux->end_magic, err);
 684
 685         return err;
 686 }
 687
 688 /*
 689  * 32-bit signal handling routines called from signal.c
 690  */
 691 int compat_setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
 692                           sigset_t *set, struct pt_regs *regs)
 693 {
 694         struct compat_rt_sigframe __user *frame;
 695         compat_stack_t stack;
 696         int err = 0;
 697
 698         frame = compat_get_sigframe(ka, regs, sizeof(*frame));
 699
 700         if (!frame)
 701                 return 1;
 702
 703         err |= copy_siginfo_to_user32(&frame->info, info);
 704
 705         __put_user_error(0, &frame->sig.uc.uc_flags, err);
 706         __put_user_error(NULL, &frame->sig.uc.uc_link, err);
 707
 708         memset(&stack, 0, sizeof(stack));
 709         stack.ss_sp = (compat_uptr_t)current->sas_ss_sp;
 710         stack.ss_flags = sas_ss_flags(regs->compat_sp);
 711         stack.ss_size = current->sas_ss_size;
 712         err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
 713
 714         err |= compat_setup_sigframe(&frame->sig, regs, set);
 715
 716         if (err == 0) {
 717                 compat_setup_return(regs, ka, frame->sig.retcode, frame, usig);
 718                 regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info;
 719                 regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc;
 720         }
 721
 722         return err;
 723 }
 724
 725 int compat_setup_frame(int usig, struct k_sigaction *ka, sigset_t *set,
 726                        struct pt_regs *regs)
 727 {
 728         struct compat_sigframe __user *frame;
 729         int err = 0;
 730
 731         frame = compat_get_sigframe(ka, regs, sizeof(*frame));
 732
 733         if (!frame)
 734                 return 1;
 735
 736         __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
 737
 738         err |= compat_setup_sigframe(frame, regs, set);
 739         if (err == 0)
 740                 compat_setup_return(regs, ka, frame->retcode, frame, usig);
 741
 742         return err;
 743 }
 744
 745 /*
 746  * RT signals don't have generic compat wrappers.
 747  * See arch/powerpc/kernel/signal_32.c
 748  */
 749 asmlinkage int compat_sys_rt_sigprocmask(int how, compat_sigset_t __user *set,
 750                                          compat_sigset_t __user *oset,
 751                                          compat_size_t sigsetsize)
 752 {
 753         sigset_t s;
 754         sigset_t __user *up;
 755         int ret;
 756         mm_segment_t old_fs = get_fs();
 757
 758         if (set) {
 759                 if (get_sigset_t(&s, set))
 760                         return -EFAULT;
 761         }
 762
 763         set_fs(KERNEL_DS);
 764         /* This is valid because of the set_fs() */
 765         up = (sigset_t __user *) &s;
 766         ret = sys_rt_sigprocmask(how, set ? up : NULL, oset ? up : NULL,
 767                                  sigsetsize);
 768         set_fs(old_fs);
 769         if (ret)
 770                 return ret;
 771         if (oset) {
 772                 if (put_sigset_t(oset, &s))
 773                         return -EFAULT;
 774         }
 775         return 0;
 776 }
 777
 778 asmlinkage int compat_sys_rt_sigpending(compat_sigset_t __user *set,
 779                                         compat_size_t sigsetsize)
 780 {
 781         sigset_t s;
 782         int ret;
 783         mm_segment_t old_fs = get_fs();
 784
 785         set_fs(KERNEL_DS);
 786         /* The __user pointer cast is valid because of the set_fs() */
 787         ret = sys_rt_sigpending((sigset_t __user *) &s, sigsetsize);
 788         set_fs(old_fs);
 789         if (!ret) {
 790                 if (put_sigset_t(set, &s))
 791                         return -EFAULT;
 792         }
 793         return ret;
 794 }
 795
 796 asmlinkage int compat_sys_rt_sigqueueinfo(int pid, int sig,
 797                                           compat_siginfo_t __user *uinfo)
 798 {
 799         siginfo_t info;
 800         int ret;
 801         mm_segment_t old_fs = get_fs();
 802
 803         ret = copy_siginfo_from_user32(&info, uinfo);
 804         if (unlikely(ret))
 805                 return ret;
 806
 807         set_fs (KERNEL_DS);
 808         /* The __user pointer cast is valid because of the set_fs() */
 809         ret = sys_rt_sigqueueinfo(pid, sig, (siginfo_t __user *) &info);
 810         set_fs (old_fs);
 811         return ret;
 812 }
 813
 814 void compat_setup_restart_syscall(struct pt_regs *regs)
 815 {
 816        regs->regs[7] = __NR_compat_restart_syscall;
 817 }