arch/s390/lib/uaccess_std.c

   1 /*
   2  *  arch/s390/lib/uaccess_std.c
   3  *
   4  *  Standard user space access functions based on mvcp/mvcs and doing
   5  *  interesting things in the secondary space mode.
   6  *
   7  *    Copyright (C) IBM Corp. 2006
   8  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   9  *               Gerald Schaefer (gerald.schaefer@de.ibm.com)
  10  */
  11
  12 #include <linux/errno.h>
  13 #include <linux/mm.h>
  14 #include <asm/uaccess.h>
  15 #include <asm/futex.h>
  16
  17 #ifndef __s390x__
  18 #define AHI     "ahi"
  19 #define ALR     "alr"
  20 #define CLR     "clr"
  21 #define LHI     "lhi"
  22 #define SLR     "slr"
  23 #else
  24 #define AHI     "aghi"
  25 #define ALR     "algr"
  26 #define CLR     "clgr"
  27 #define LHI     "lghi"
  28 #define SLR     "slgr"
  29 #endif
  30
  31 size_t copy_from_user_std(size_t size, const void __user *ptr, void *x)
  32 {
  33         unsigned long tmp1, tmp2;
  34
  35         tmp1 = -256UL;
  36         asm volatile(
  37                 "0: mvcp  0(%0,%2),0(%1),%3\n"
  38                 "   jz    8f\n"
  39                 "1:"ALR"  %0,%3\n"
  40                 "   la    %1,256(%1)\n"
  41                 "   la    %2,256(%2)\n"
  42                 "2: mvcp  0(%0,%2),0(%1),%3\n"
  43                 "   jnz   1b\n"
  44                 "   j     8f\n"
  45                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
  46                 "  "LHI"  %3,-4096\n"
  47                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
  48                 "  "SLR"  %4,%1\n"
  49                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
  50                 "   jnh   5f\n"
  51                 "4: mvcp  0(%4,%2),0(%1),%3\n"
  52                 "  "SLR"  %0,%4\n"
  53                 "  "ALR"  %2,%4\n"
  54                 "5:"LHI"  %4,-1\n"
  55                 "  "ALR"  %4,%0\n"      /* copy remaining size, subtract 1 */
  56                 "   bras  %3,7f\n"      /* memset loop */
  57                 "   xc    0(1,%2),0(%2)\n"
  58                 "6: xc    0(256,%2),0(%2)\n"
  59                 "   la    %2,256(%2)\n"
  60                 "7:"AHI"  %4,-256\n"
  61                 "   jnm   6b\n"
  62                 "   ex    %4,0(%3)\n"
  63                 "   j     9f\n"
  64                 "8:"SLR"  %0,%0\n"
  65                 "9: \n"
  66                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b)
  67                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  68                 : : "cc", "memory");
  69         return size;
  70 }
  71
  72 size_t copy_from_user_std_small(size_t size, const void __user *ptr, void *x)
  73 {
  74         unsigned long tmp1, tmp2;
  75
  76         tmp1 = 0UL;
  77         asm volatile(
  78                 "0: mvcp  0(%0,%2),0(%1),%3\n"
  79                 "  "SLR"  %0,%0\n"
  80                 "   j     5f\n"
  81                 "1: la    %4,255(%1)\n" /* %4 = ptr + 255 */
  82                 "  "LHI"  %3,-4096\n"
  83                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
  84                 "  "SLR"  %4,%1\n"
  85                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
  86                 "   jnh   5f\n"
  87                 "2: mvcp  0(%4,%2),0(%1),%3\n"
  88                 "  "SLR"  %0,%4\n"
  89                 "  "ALR"  %2,%4\n"
  90                 "3:"LHI"  %4,-1\n"
  91                 "  "ALR"  %4,%0\n"      /* copy remaining size, subtract 1 */
  92                 "   bras  %3,4f\n"
  93                 "   xc    0(1,%2),0(%2)\n"
  94                 "4: ex    %4,0(%3)\n"
  95                 "5:\n"
  96                 EX_TABLE(0b,1b) EX_TABLE(2b,3b)
  97                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  98                 : : "cc", "memory");
  99         return size;
 100 }
 101
 102 size_t copy_to_user_std(size_t size, void __user *ptr, const void *x)
 103 {
 104         unsigned long tmp1, tmp2;
 105
 106         tmp1 = -256UL;
 107         asm volatile(
 108                 "0: mvcs  0(%0,%1),0(%2),%3\n"
 109                 "   jz    5f\n"
 110                 "1:"ALR"  %0,%3\n"
 111                 "   la    %1,256(%1)\n"
 112                 "   la    %2,256(%2)\n"
 113                 "2: mvcs  0(%0,%1),0(%2),%3\n"
 114                 "   jnz   1b\n"
 115                 "   j     5f\n"
 116                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
 117                 "  "LHI"  %3,-4096\n"
 118                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
 119                 "  "SLR"  %4,%1\n"
 120                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
 121                 "   jnh   6f\n"
 122                 "4: mvcs  0(%4,%1),0(%2),%3\n"
 123                 "  "SLR"  %0,%4\n"
 124                 "   j     6f\n"
 125                 "5:"SLR"  %0,%0\n"
 126                 "6: \n"
 127                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
 128                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 129                 : : "cc", "memory");
 130         return size;
 131 }
 132
 133 size_t copy_to_user_std_small(size_t size, void __user *ptr, const void *x)
 134 {
 135         unsigned long tmp1, tmp2;
 136
 137         tmp1 = 0UL;
 138         asm volatile(
 139                 "0: mvcs  0(%0,%1),0(%2),%3\n"
 140                 "  "SLR"  %0,%0\n"
 141                 "   j     3f\n"
 142                 "1: la    %4,255(%1)\n" /* ptr + 255 */
 143                 "  "LHI"  %3,-4096\n"
 144                 "   nr    %4,%3\n"      /* (ptr + 255) & -4096UL */
 145                 "  "SLR"  %4,%1\n"
 146                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
 147                 "   jnh   3f\n"
 148                 "2: mvcs  0(%4,%1),0(%2),%3\n"
 149                 "  "SLR"  %0,%4\n"
 150                 "3:\n"
 151                 EX_TABLE(0b,1b) EX_TABLE(2b,3b)
 152                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 153                 : : "cc", "memory");
 154         return size;
 155 }
 156
 157 size_t copy_in_user_std(size_t size, void __user *to, const void __user *from)
 158 {
 159         unsigned long tmp1;
 160
 161         asm volatile(
 162                 "  "AHI"  %0,-1\n"
 163                 "   jo    5f\n"
 164                 "   sacf  256\n"
 165                 "   bras  %3,3f\n"
 166                 "0:"AHI"  %0,257\n"
 167                 "1: mvc   0(1,%1),0(%2)\n"
 168                 "   la    %1,1(%1)\n"
 169                 "   la    %2,1(%2)\n"
 170                 "  "AHI"  %0,-1\n"
 171                 "   jnz   1b\n"
 172                 "   j     5f\n"
 173                 "2: mvc   0(256,%1),0(%2)\n"
 174                 "   la    %1,256(%1)\n"
 175                 "   la    %2,256(%2)\n"
 176                 "3:"AHI"  %0,-256\n"
 177                 "   jnm   2b\n"
 178                 "4: ex    %0,1b-0b(%3)\n"
 179                 "   sacf  0\n"
 180                 "5: "SLR"  %0,%0\n"
 181                 "6:\n"
 182                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 183                 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
 184                 : : "cc", "memory");
 185         return size;
 186 }
 187
 188 size_t clear_user_std(size_t size, void __user *to)
 189 {
 190         unsigned long tmp1, tmp2;
 191
 192         asm volatile(
 193                 "  "AHI"  %0,-1\n"
 194                 "   jo    5f\n"
 195                 "   sacf  256\n"
 196                 "   bras  %3,3f\n"
 197                 "   xc    0(1,%1),0(%1)\n"
 198                 "0:"AHI"  %0,257\n"
 199                 "   la    %2,255(%1)\n" /* %2 = ptr + 255 */
 200                 "   srl   %2,12\n"
 201                 "   sll   %2,12\n"      /* %2 = (ptr + 255) & -4096 */
 202                 "  "SLR"  %2,%1\n"
 203                 "  "CLR"  %0,%2\n"      /* clear crosses next page boundary? */
 204                 "   jnh   5f\n"
 205                 "  "AHI"  %2,-1\n"
 206                 "1: ex    %2,0(%3)\n"
 207                 "  "AHI"  %2,1\n"
 208                 "  "SLR"  %0,%2\n"
 209                 "   j     5f\n"
 210                 "2: xc    0(256,%1),0(%1)\n"
 211                 "   la    %1,256(%1)\n"
 212                 "3:"AHI"  %0,-256\n"
 213                 "   jnm   2b\n"
 214                 "4: ex    %0,0(%3)\n"
 215                 "   sacf  0\n"
 216                 "5: "SLR"  %0,%0\n"
 217                 "6:\n"
 218                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 219                 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
 220                 : : "cc", "memory");
 221         return size;
 222 }
 223
 224 size_t strnlen_user_std(size_t size, const char __user *src)
 225 {
 226         register unsigned long reg0 asm("0") = 0UL;
 227         unsigned long tmp1, tmp2;
 228
 229         asm volatile(
 230                 "   la    %2,0(%1)\n"
 231                 "   la    %3,0(%0,%1)\n"
 232                 "  "SLR"  %0,%0\n"
 233                 "   sacf  256\n"
 234                 "0: srst  %3,%2\n"
 235                 "   jo    0b\n"
 236                 "   la    %0,1(%3)\n"   /* strnlen_user results includes \0 */
 237                 "  "SLR"  %0,%1\n"
 238                 "1: sacf  0\n"
 239                 EX_TABLE(0b,1b)
 240                 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
 241                 : "d" (reg0) : "cc", "memory");
 242         return size;
 243 }
 244
 245 size_t strncpy_from_user_std(size_t size, const char __user *src, char *dst)
 246 {
 247         register unsigned long reg0 asm("0") = 0UL;
 248         unsigned long tmp1, tmp2;
 249
 250         asm volatile(
 251                 "   la    %3,0(%1)\n"
 252                 "   la    %4,0(%0,%1)\n"
 253                 "   sacf  256\n"
 254                 "0: srst  %4,%3\n"
 255                 "   jo    0b\n"
 256                 "   sacf  0\n"
 257                 "   la    %0,0(%4)\n"
 258                 "   jh    1f\n"         /* found \0 in string ? */
 259                 "  "AHI"  %4,1\n"       /* include \0 in copy */
 260                 "1:"SLR"  %0,%1\n"      /* %0 = return length (without \0) */
 261                 "  "SLR"  %4,%1\n"      /* %4 = copy length (including \0) */
 262                 "2: mvcp  0(%4,%2),0(%1),%5\n"
 263                 "   jz    9f\n"
 264                 "3:"AHI"  %4,-256\n"
 265                 "   la    %1,256(%1)\n"
 266                 "   la    %2,256(%2)\n"
 267                 "4: mvcp  0(%4,%2),0(%1),%5\n"
 268                 "   jnz   3b\n"
 269                 "   j     9f\n"
 270                 "7: sacf  0\n"
 271                 "8:"LHI"  %0,%6\n"
 272                 "9:\n"
 273                 EX_TABLE(0b,7b) EX_TABLE(2b,8b) EX_TABLE(4b,8b)
 274                 : "+a" (size), "+a" (src), "+d" (dst), "=a" (tmp1), "=a" (tmp2)
 275                 : "d" (reg0), "K" (-EFAULT) : "cc", "memory");
 276         return size;
 277 }
 278
 279 #define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)      \
 280         asm volatile(                                                   \
 281                 "   sacf  256\n"                                        \
 282                 "0: l     %1,0(%6)\n"                                   \
 283                 "1:"insn                                                \
 284                 "2: cs    %1,%2,0(%6)\n"                                \
 285                 "3: jl    1b\n"                                         \
 286                 "   lhi   %0,0\n"                                       \
 287                 "4: sacf  0\n"                                          \
 288                 EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b)         \
 289                 : "=d" (ret), "=&d" (oldval), "=&d" (newval),           \
 290                   "=m" (*uaddr)                                         \
 291                 : "0" (-EFAULT), "d" (oparg), "a" (uaddr),              \
 292                   "m" (*uaddr) : "cc");
 293
 294 int futex_atomic_op(int op, int __user *uaddr, int oparg, int *old)
 295 {
 296         int oldval = 0, newval, ret;
 297
 298         inc_preempt_count();
 299
 300         switch (op) {
 301         case FUTEX_OP_SET:
 302                 __futex_atomic_op("lr %2,%5\n",
 303                                   ret, oldval, newval, uaddr, oparg);
 304                 break;
 305         case FUTEX_OP_ADD:
 306                 __futex_atomic_op("lr %2,%1\nar %2,%5\n",
 307                                   ret, oldval, newval, uaddr, oparg);
 308                 break;
 309         case FUTEX_OP_OR:
 310                 __futex_atomic_op("lr %2,%1\nor %2,%5\n",
 311                                   ret, oldval, newval, uaddr, oparg);
 312                 break;
 313         case FUTEX_OP_ANDN:
 314                 __futex_atomic_op("lr %2,%1\nnr %2,%5\n",
 315                                   ret, oldval, newval, uaddr, oparg);
 316                 break;
 317         case FUTEX_OP_XOR:
 318                 __futex_atomic_op("lr %2,%1\nxr %2,%5\n",
 319                                   ret, oldval, newval, uaddr, oparg);
 320                 break;
 321         default:
 322                 ret = -ENOSYS;
 323         }
 324         dec_preempt_count();
 325         *old = oldval;
 326         return ret;
 327 }
 328
 329 int futex_atomic_cmpxchg(int __user *uaddr, int oldval, int newval)
 330 {
 331         int ret;
 332
 333         asm volatile(
 334                 "   sacf 256\n"
 335                 "   cs   %1,%4,0(%5)\n"
 336                 "0: lr   %0,%1\n"
 337                 "1: sacf 0\n"
 338                 EX_TABLE(0b,1b)
 339                 : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
 340                 : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
 341                 : "cc", "memory" );
 342         return ret;
 343 }
 344
 345 struct uaccess_ops uaccess_std = {
 346         .copy_from_user = copy_from_user_std,
 347         .copy_from_user_small = copy_from_user_std_small,
 348         .copy_to_user = copy_to_user_std,
 349         .copy_to_user_small = copy_to_user_std_small,
 350         .copy_in_user = copy_in_user_std,
 351         .clear_user = clear_user_std,
 352         .strnlen_user = strnlen_user_std,
 353         .strncpy_from_user = strncpy_from_user_std,
 354         .futex_atomic_op = futex_atomic_op,
 355         .futex_atomic_cmpxchg = futex_atomic_cmpxchg,
 356 };