arch/parisc/kernel/signal32.c

   1 /*    Signal support for 32-bit kernel builds
   2  *
   3  *    Copyright (C) 2001 Matthew Wilcox <willy at parisc-linux.org>
   4  *    Copyright (C) 2006 Kyle McMartin <kyle at parisc-linux.org>
   5  *
   6  *    Code was mostly borrowed from kernel/signal.c.
   7  *    See kernel/signal.c for additional Copyrights.
   8  *
   9  *
  10  *    This program is free software; you can redistribute it and/or modify
  11  *    it under the terms of the GNU General Public License as published by
  12  *    the Free Software Foundation; either version 2 of the License, or
  13  *    (at your option) any later version.
  14  *
  15  *    This program is distributed in the hope that it will be useful,
  16  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *    GNU General Public License for more details.
  19  *
  20  *    You should have received a copy of the GNU General Public License
  21  *    along with this program; if not, write to the Free Software
  22  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  */
  24
  25 #include <linux/compat.h>
  26 #include <linux/slab.h>
  27 #include <linux/module.h>
  28 #include <linux/unistd.h>
  29 #include <linux/smp_lock.h>
  30 #include <linux/init.h>
  31 #include <linux/sched.h>
  32 #include <linux/syscalls.h>
  33 #include <linux/types.h>
  34 #include <linux/errno.h>
  35
  36 #include <asm/uaccess.h>
  37
  38 #include "signal32.h"
  39 #include "sys32.h"
  40
  41 #define DEBUG_COMPAT_SIG 0
  42 #define DEBUG_COMPAT_SIG_LEVEL 2
  43
  44 #if DEBUG_COMPAT_SIG
  45 #define DBG(LEVEL, ...) \
  46         ((DEBUG_COMPAT_SIG_LEVEL >= LEVEL) \
  47         ? printk(__VA_ARGS__) : (void) 0)
  48 #else
  49 #define DBG(LEVEL, ...)
  50 #endif
  51
  52 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  53
  54 inline void
  55 sigset_32to64(sigset_t *s64, compat_sigset_t *s32)
  56 {
  57         s64->sig[0] = s32->sig[0] | ((unsigned long)s32->sig[1] << 32);
  58 }
  59
  60 inline void
  61 sigset_64to32(compat_sigset_t *s32, sigset_t *s64)
  62 {
  63         s32->sig[0] = s64->sig[0] & 0xffffffffUL;
  64         s32->sig[1] = (s64->sig[0] >> 32) & 0xffffffffUL;
  65 }
  66
  67 static int
  68 put_sigset32(compat_sigset_t __user *up, sigset_t *set, size_t sz)
  69 {
  70         compat_sigset_t s;
  71
  72         if (sz != sizeof *set) panic("put_sigset32()");
  73         sigset_64to32(&s, set);
  74
  75         return copy_to_user(up, &s, sizeof s);
  76 }
  77
  78 static int
  79 get_sigset32(compat_sigset_t __user *up, sigset_t *set, size_t sz)
  80 {
  81         compat_sigset_t s;
  82         int r;
  83
  84         if (sz != sizeof *set) panic("put_sigset32()");
  85
  86         if ((r = copy_from_user(&s, up, sz)) == 0) {
  87                 sigset_32to64(set, &s);
  88         }
  89
  90         return r;
  91 }
  92
  93 int sys32_rt_sigprocmask(int how, compat_sigset_t __user *set, compat_sigset_t __user *oset,
  94                                     unsigned int sigsetsize)
  95 {
  96         sigset_t old_set, new_set;
  97         int ret;
  98
  99         if (set && get_sigset32(set, &new_set, sigsetsize))
 100                 return -EFAULT;
 101
 102         KERNEL_SYSCALL(ret, sys_rt_sigprocmask, how, set ? (sigset_t __user *)&new_set : NULL,
 103                                  oset ? (sigset_t __user *)&old_set : NULL, sigsetsize);
 104
 105         if (!ret && oset && put_sigset32(oset, &old_set, sigsetsize))
 106                 return -EFAULT;
 107
 108         return ret;
 109 }
 110
 111
 112 int sys32_rt_sigpending(compat_sigset_t __user *uset, unsigned int sigsetsize)
 113 {
 114         int ret;
 115         sigset_t set;
 116
 117         KERNEL_SYSCALL(ret, sys_rt_sigpending, (sigset_t __user *)&set, sigsetsize);
 118
 119         if (!ret && put_sigset32(uset, &set, sigsetsize))
 120                 return -EFAULT;
 121
 122         return ret;
 123 }
 124
 125 long
 126 sys32_rt_sigaction(int sig, const struct sigaction32 __user *act, struct sigaction32 __user *oact,
 127                  size_t sigsetsize)
 128 {
 129         struct k_sigaction32 new_sa32, old_sa32;
 130         struct k_sigaction new_sa, old_sa;
 131         int ret = -EINVAL;
 132
 133         if (act) {
 134                 if (copy_from_user(&new_sa32.sa, act, sizeof new_sa32.sa))
 135                         return -EFAULT;
 136                 new_sa.sa.sa_handler = (__sighandler_t)(unsigned long)new_sa32.sa.sa_handler;
 137                 new_sa.sa.sa_flags = new_sa32.sa.sa_flags;
 138                 sigset_32to64(&new_sa.sa.sa_mask, &new_sa32.sa.sa_mask);
 139         }
 140
 141         ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
 142
 143         if (!ret && oact) {
 144                 sigset_64to32(&old_sa32.sa.sa_mask, &old_sa.sa.sa_mask);
 145                 old_sa32.sa.sa_flags = old_sa.sa.sa_flags;
 146                 old_sa32.sa.sa_handler = (__sighandler_t32)(unsigned long)old_sa.sa.sa_handler;
 147                 if (copy_to_user(oact, &old_sa32.sa, sizeof old_sa32.sa))
 148                         return -EFAULT;
 149         }
 150         return ret;
 151 }
 152
 153 int
 154 do_sigaltstack32 (const compat_stack_t __user *uss32, compat_stack_t __user *uoss32, unsigned long sp)
 155 {
 156         compat_stack_t ss32, oss32;
 157         stack_t ss, oss;
 158         stack_t *ssp = NULL, *ossp = NULL;
 159         int ret;
 160
 161         if (uss32) {
 162                 if (copy_from_user(&ss32, uss32, sizeof ss32))
 163                         return -EFAULT;
 164
 165                 ss.ss_sp = (void __user *)(unsigned long)ss32.ss_sp;
 166                 ss.ss_flags = ss32.ss_flags;
 167                 ss.ss_size = ss32.ss_size;
 168
 169                 ssp = &ss;
 170         }
 171
 172         if (uoss32)
 173                 ossp = &oss;
 174
 175         KERNEL_SYSCALL(ret, do_sigaltstack, (const stack_t __user *)ssp, (stack_t __user *)ossp, sp);
 176
 177         if (!ret && uoss32) {
 178                 oss32.ss_sp = (unsigned int)(unsigned long)oss.ss_sp;
 179                 oss32.ss_flags = oss.ss_flags;
 180                 oss32.ss_size = oss.ss_size;
 181                 if (copy_to_user(uoss32, &oss32, sizeof *uoss32))
 182                         return -EFAULT;
 183         }
 184
 185         return ret;
 186 }
 187
 188 long
 189 restore_sigcontext32(struct compat_sigcontext __user *sc, struct compat_regfile __user * rf,
 190                 struct pt_regs *regs)
 191 {
 192         long err = 0;
 193         compat_uint_t compat_reg;
 194         compat_uint_t compat_regt;
 195         int regn;
 196
 197         /* When loading 32-bit values into 64-bit registers make
 198            sure to clear the upper 32-bits */
 199         DBG(2,"restore_sigcontext32: PER_LINUX32 process\n");
 200         DBG(2,"restore_sigcontext32: sc = 0x%p, rf = 0x%p, regs = 0x%p\n", sc, rf, regs);
 201         DBG(2,"restore_sigcontext32: compat_sigcontext is %#lx bytes\n", sizeof(*sc));
 202         for(regn=0; regn < 32; regn++){
 203                 err |= __get_user(compat_reg,&sc->sc_gr[regn]);
 204                 regs->gr[regn] = compat_reg;
 205                 /* Load upper half */
 206                 err |= __get_user(compat_regt,&rf->rf_gr[regn]);
 207                 regs->gr[regn] = ((u64)compat_regt << 32) | (u64)compat_reg;
 208                 DBG(3,"restore_sigcontext32: gr%02d = %#lx (%#x / %#x)\n",
 209                                 regn, regs->gr[regn], compat_regt, compat_reg);
 210         }
 211         DBG(2,"restore_sigcontext32: sc->sc_fr = 0x%p (%#lx)\n",sc->sc_fr, sizeof(sc->sc_fr));
 212         /* XXX: BE WARNED FR's are 64-BIT! */
 213         err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr));
 214
 215         /* Better safe than sorry, pass __get_user two things of
 216            the same size and let gcc do the upward conversion to
 217            64-bits */
 218         err |= __get_user(compat_reg, &sc->sc_iaoq[0]);
 219         /* Load upper half */
 220         err |= __get_user(compat_regt, &rf->rf_iaoq[0]);
 221         regs->iaoq[0] = ((u64)compat_regt << 32) | (u64)compat_reg;
 222         DBG(2,"restore_sigcontext32: upper half of iaoq[0] = %#lx\n", compat_regt);
 223         DBG(2,"restore_sigcontext32: sc->sc_iaoq[0] = %p => %#x\n",
 224                         &sc->sc_iaoq[0], compat_reg);
 225
 226         err |= __get_user(compat_reg, &sc->sc_iaoq[1]);
 227         /* Load upper half */
 228         err |= __get_user(compat_regt, &rf->rf_iaoq[1]);
 229         regs->iaoq[1] = ((u64)compat_regt << 32) | (u64)compat_reg;
 230         DBG(2,"restore_sigcontext32: upper half of iaoq[1] = %#lx\n", compat_regt);
 231         DBG(2,"restore_sigcontext32: sc->sc_iaoq[1] = %p => %#x\n",
 232                         &sc->sc_iaoq[1],compat_reg);
 233         DBG(2,"restore_sigcontext32: iaoq is %#lx / %#lx\n",
 234                         regs->iaoq[0],regs->iaoq[1]);
 235
 236         err |= __get_user(compat_reg, &sc->sc_iasq[0]);
 237         /* Load the upper half for iasq */
 238         err |= __get_user(compat_regt, &rf->rf_iasq[0]);
 239         regs->iasq[0] = ((u64)compat_regt << 32) | (u64)compat_reg;
 240         DBG(2,"restore_sigcontext32: upper half of iasq[0] = %#lx\n", compat_regt);
 241
 242         err |= __get_user(compat_reg, &sc->sc_iasq[1]);
 243         /* Load the upper half for iasq */
 244         err |= __get_user(compat_regt, &rf->rf_iasq[1]);
 245         regs->iasq[1] = ((u64)compat_regt << 32) | (u64)compat_reg;
 246         DBG(2,"restore_sigcontext32: upper half of iasq[1] = %#lx\n", compat_regt);
 247         DBG(2,"restore_sigcontext32: iasq is %#lx / %#lx\n",
 248                 regs->iasq[0],regs->iasq[1]);
 249
 250         err |= __get_user(compat_reg, &sc->sc_sar);
 251         /* Load the upper half for sar */
 252         err |= __get_user(compat_regt, &rf->rf_sar);
 253         regs->sar = ((u64)compat_regt << 32) | (u64)compat_reg;
 254         DBG(2,"restore_sigcontext32: upper_half & sar = %#lx\n", compat_regt);
 255         DBG(2,"restore_sigcontext32: sar is %#lx\n", regs->sar);
 256         DBG(2,"restore_sigcontext32: r28 is %ld\n", regs->gr[28]);
 257
 258         return err;
 259 }
 260
 261 /*
 262  * Set up the sigcontext structure for this process.
 263  * This is not an easy task if the kernel is 64-bit, it will require
 264  * that we examine the process personality to determine if we need to
 265  * truncate for a 32-bit userspace.
 266  */
 267 long
 268 setup_sigcontext32(struct compat_sigcontext __user *sc, struct compat_regfile __user * rf,
 269                 struct pt_regs *regs, int in_syscall)
 270 {
 271         compat_int_t flags = 0;
 272         long err = 0;
 273         compat_uint_t compat_reg;
 274         compat_uint_t compat_regb;
 275         int regn;
 276
 277         if (on_sig_stack((unsigned long) sc))
 278                 flags |= PARISC_SC_FLAG_ONSTACK;
 279
 280         if (in_syscall) {
 281
 282                 DBG(1,"setup_sigcontext32: in_syscall\n");
 283
 284                 flags |= PARISC_SC_FLAG_IN_SYSCALL;
 285                 /* Truncate gr31 */
 286                 compat_reg = (compat_uint_t)(regs->gr[31]);
 287                 /* regs->iaoq is undefined in the syscall return path */
 288                 err |= __put_user(compat_reg, &sc->sc_iaoq[0]);
 289                 DBG(2,"setup_sigcontext32: sc->sc_iaoq[0] = %p <= %#x\n",
 290                                 &sc->sc_iaoq[0], compat_reg);
 291
 292                 /* Store upper half */
 293                 compat_reg = (compat_uint_t)(regs->gr[32] >> 32);
 294                 err |= __put_user(compat_reg, &rf->rf_iaoq[0]);
 295                 DBG(2,"setup_sigcontext32: upper half iaoq[0] = %#x\n", compat_reg);
 296
 297
 298                 compat_reg = (compat_uint_t)(regs->gr[31]+4);
 299                 err |= __put_user(compat_reg, &sc->sc_iaoq[1]);
 300                 DBG(2,"setup_sigcontext32: sc->sc_iaoq[1] = %p <= %#x\n",
 301                                 &sc->sc_iaoq[1], compat_reg);
 302                 /* Store upper half */
 303                 compat_reg = (compat_uint_t)((regs->gr[32]+4) >> 32);
 304                 err |= __put_user(compat_reg, &rf->rf_iaoq[1]);
 305                 DBG(2,"setup_sigcontext32: upper half iaoq[1] = %#x\n", compat_reg);
 306
 307                 /* Truncate sr3 */
 308                 compat_reg = (compat_uint_t)(regs->sr[3]);
 309                 err |= __put_user(compat_reg, &sc->sc_iasq[0]);
 310                 err |= __put_user(compat_reg, &sc->sc_iasq[1]);
 311
 312                 /* Store upper half */
 313                 compat_reg = (compat_uint_t)(regs->sr[3] >> 32);
 314                 err |= __put_user(compat_reg, &rf->rf_iasq[0]);
 315                 err |= __put_user(compat_reg, &rf->rf_iasq[1]);
 316
 317                 DBG(2,"setup_sigcontext32: upper half iasq[0] = %#x\n", compat_reg);
 318                 DBG(2,"setup_sigcontext32: upper half iasq[1] = %#x\n", compat_reg);
 319                 DBG(1,"setup_sigcontext32: iaoq %#lx / %#lx\n",
 320                         regs->gr[31], regs->gr[31]+4);
 321
 322         } else {
 323
 324                 compat_reg = (compat_uint_t)(regs->iaoq[0]);
 325                 err |= __put_user(compat_reg, &sc->sc_iaoq[0]);
 326                 DBG(2,"setup_sigcontext32: sc->sc_iaoq[0] = %p <= %#x\n",
 327                                 &sc->sc_iaoq[0], compat_reg);
 328                 /* Store upper half */
 329                 compat_reg = (compat_uint_t)(regs->iaoq[0] >> 32);
 330                 err |= __put_user(compat_reg, &rf->rf_iaoq[0]);
 331                 DBG(2,"setup_sigcontext32: upper half iaoq[0] = %#x\n", compat_reg);
 332
 333                 compat_reg = (compat_uint_t)(regs->iaoq[1]);
 334                 err |= __put_user(compat_reg, &sc->sc_iaoq[1]);
 335                 DBG(2,"setup_sigcontext32: sc->sc_iaoq[1] = %p <= %#x\n",
 336                                 &sc->sc_iaoq[1], compat_reg);
 337                 /* Store upper half */
 338                 compat_reg = (compat_uint_t)(regs->iaoq[1] >> 32);
 339                 err |= __put_user(compat_reg, &rf->rf_iaoq[1]);
 340                 DBG(2,"setup_sigcontext32: upper half iaoq[1] = %#x\n", compat_reg);
 341
 342
 343                 compat_reg = (compat_uint_t)(regs->iasq[0]);
 344                 err |= __put_user(compat_reg, &sc->sc_iasq[0]);
 345                 DBG(2,"setup_sigcontext32: sc->sc_iasq[0] = %p <= %#x\n",
 346                                 &sc->sc_iasq[0], compat_reg);
 347                 /* Store upper half */
 348                 compat_reg = (compat_uint_t)(regs->iasq[0] >> 32);
 349                 err |= __put_user(compat_reg, &rf->rf_iasq[0]);
 350                 DBG(2,"setup_sigcontext32: upper half iasq[0] = %#x\n", compat_reg);
 351
 352
 353                 compat_reg = (compat_uint_t)(regs->iasq[1]);
 354                 err |= __put_user(compat_reg, &sc->sc_iasq[1]);
 355                 DBG(2,"setup_sigcontext32: sc->sc_iasq[1] = %p <= %#x\n",
 356                                 &sc->sc_iasq[1], compat_reg);
 357                 /* Store upper half */
 358                 compat_reg = (compat_uint_t)(regs->iasq[1] >> 32);
 359                 err |= __put_user(compat_reg, &rf->rf_iasq[1]);
 360                 DBG(2,"setup_sigcontext32: upper half iasq[1] = %#x\n", compat_reg);
 361
 362                 /* Print out the IAOQ for debugging */
 363                 DBG(1,"setup_sigcontext32: ia0q %#lx / %#lx\n",
 364                         regs->iaoq[0], regs->iaoq[1]);
 365         }
 366
 367         err |= __put_user(flags, &sc->sc_flags);
 368
 369         DBG(1,"setup_sigcontext32: Truncating general registers.\n");
 370
 371         for(regn=0; regn < 32; regn++){
 372                 /* Truncate a general register */
 373                 compat_reg = (compat_uint_t)(regs->gr[regn]);
 374                 err |= __put_user(compat_reg, &sc->sc_gr[regn]);
 375                 /* Store upper half */
 376                 compat_regb = (compat_uint_t)(regs->gr[regn] >> 32);
 377                 err |= __put_user(compat_regb, &rf->rf_gr[regn]);
 378
 379                 /* DEBUG: Write out the "upper / lower" register data */
 380                 DBG(2,"setup_sigcontext32: gr%02d = %#x / %#x\n", regn,
 381                                 compat_regb, compat_reg);
 382         }
 383
 384         /* Copy the floating point registers (same size)
 385            XXX: BE WARNED FR's are 64-BIT! */
 386         DBG(1,"setup_sigcontext32: Copying from regs to sc, "
 387               "sc->sc_fr size = %#lx, regs->fr size = %#lx\n",
 388                 sizeof(regs->fr), sizeof(sc->sc_fr));
 389         err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
 390
 391         compat_reg = (compat_uint_t)(regs->sar);
 392         err |= __put_user(compat_reg, &sc->sc_sar);
 393         DBG(2,"setup_sigcontext32: sar is %#x\n", compat_reg);
 394         /* Store upper half */
 395         compat_reg = (compat_uint_t)(regs->sar >> 32);
 396         err |= __put_user(compat_reg, &rf->rf_sar);
 397         DBG(2,"setup_sigcontext32: upper half sar = %#x\n", compat_reg);
 398         DBG(1,"setup_sigcontext32: r28 is %ld\n", regs->gr[28]);
 399
 400         return err;
 401 }
 402
 403 int
 404 copy_siginfo_from_user32 (siginfo_t *to, compat_siginfo_t __user *from)
 405 {
 406         compat_uptr_t addr;
 407         int err;
 408
 409         if (!access_ok(VERIFY_READ, from, sizeof(compat_siginfo_t)))
 410                 return -EFAULT;
 411
 412         err = __get_user(to->si_signo, &from->si_signo);
 413         err |= __get_user(to->si_errno, &from->si_errno);
 414         err |= __get_user(to->si_code, &from->si_code);
 415
 416         if (to->si_code < 0)
 417                 err |= __copy_from_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
 418         else {
 419                 switch (to->si_code >> 16) {
 420                       case __SI_CHLD >> 16:
 421                         err |= __get_user(to->si_utime, &from->si_utime);
 422                         err |= __get_user(to->si_stime, &from->si_stime);
 423                         err |= __get_user(to->si_status, &from->si_status);
 424                       default:
 425                         err |= __get_user(to->si_pid, &from->si_pid);
 426                         err |= __get_user(to->si_uid, &from->si_uid);
 427                         break;
 428                       case __SI_FAULT >> 16:
 429                         err |= __get_user(addr, &from->si_addr);
 430                         to->si_addr = compat_ptr(addr);
 431                         break;
 432                       case __SI_POLL >> 16:
 433                         err |= __get_user(to->si_band, &from->si_band);
 434                         err |= __get_user(to->si_fd, &from->si_fd);
 435                         break;
 436                       case __SI_RT >> 16: /* This is not generated by the kernel as of now.  */
 437                       case __SI_MESGQ >> 16:
 438                         err |= __get_user(to->si_pid, &from->si_pid);
 439                         err |= __get_user(to->si_uid, &from->si_uid);
 440                         err |= __get_user(to->si_int, &from->si_int);
 441                         break;
 442                 }
 443         }
 444         return err;
 445 }
 446
 447 int
 448 copy_siginfo_to_user32 (compat_siginfo_t __user *to, siginfo_t *from)
 449 {
 450         compat_uptr_t addr;
 451         compat_int_t val;
 452         int err;
 453
 454         if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
 455                 return -EFAULT;
 456
 457         /* If you change siginfo_t structure, please be sure
 458            this code is fixed accordingly.
 459            It should never copy any pad contained in the structure
 460            to avoid security leaks, but must copy the generic
 461            3 ints plus the relevant union member.
 462            This routine must convert siginfo from 64bit to 32bit as well
 463            at the same time.  */
 464         err = __put_user(from->si_signo, &to->si_signo);
 465         err |= __put_user(from->si_errno, &to->si_errno);
 466         err |= __put_user((short)from->si_code, &to->si_code);
 467         if (from->si_code < 0)
 468                 err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
 469         else {
 470                 switch (from->si_code >> 16) {
 471                 case __SI_CHLD >> 16:
 472                         err |= __put_user(from->si_utime, &to->si_utime);
 473                         err |= __put_user(from->si_stime, &to->si_stime);
 474                         err |= __put_user(from->si_status, &to->si_status);
 475                 default:
 476                         err |= __put_user(from->si_pid, &to->si_pid);
 477                         err |= __put_user(from->si_uid, &to->si_uid);
 478                         break;
 479                 case __SI_FAULT >> 16:
 480                         addr = ptr_to_compat(from->si_addr);
 481                         err |= __put_user(addr, &to->si_addr);
 482                         break;
 483                 case __SI_POLL >> 16:
 484                         err |= __put_user(from->si_band, &to->si_band);
 485                         err |= __put_user(from->si_fd, &to->si_fd);
 486                         break;
 487                 case __SI_TIMER >> 16:
 488                         err |= __put_user(from->si_tid, &to->si_tid);
 489                         err |= __put_user(from->si_overrun, &to->si_overrun);
 490                         val = (compat_int_t)from->si_int;
 491                         err |= __put_user(val, &to->si_int);
 492                         break;
 493                 case __SI_RT >> 16:     /* Not generated by the kernel as of now.  */
 494                 case __SI_MESGQ >> 16:
 495                         err |= __put_user(from->si_uid, &to->si_uid);
 496                         err |= __put_user(from->si_pid, &to->si_pid);
 497                         val = (compat_int_t)from->si_int;
 498                         err |= __put_user(val, &to->si_int);
 499                         break;
 500                 }
 501         }
 502         return err;
 503 }
 504
 505 asmlinkage long compat_sys_rt_sigqueueinfo(int pid, int sig,
 506         struct compat_siginfo __user *uinfo)
 507 {
 508         siginfo_t info;
 509
 510         if (copy_siginfo_from_user32(&info, uinfo))
 511                 return -EFAULT;
 512
 513         /* Not even root can pretend to send signals from the kernel.
 514            Nor can they impersonate a kill(), which adds source info.  */
 515         if (info.si_code >= 0)
 516                 return -EPERM;
 517         info.si_signo = sig;
 518
 519         /* POSIX.1b doesn't mention process groups.  */
 520         return kill_proc_info(sig, &info, pid);
 521 }
 522