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    5f\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     5f\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   6f\n"
  51                 "4: mvcp  0(%4,%2),0(%1),%3\n"
  52                 "  "SLR"  %0,%4\n"
  53                 "   j     6f\n"
  54                 "5:"SLR"  %0,%0\n"
  55                 "6: \n"
  56                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
  57                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  58                 : : "cc", "memory");
  59         return size;
  60 }
  61
  62 size_t copy_from_user_std_small(size_t size, const void __user *ptr, void *x)
  63 {
  64         unsigned long tmp1, tmp2;
  65
  66         tmp1 = 0UL;
  67         asm volatile(
  68                 "0: mvcp  0(%0,%2),0(%1),%3\n"
  69                 "  "SLR"  %0,%0\n"
  70                 "   j     3f\n"
  71                 "1: la    %4,255(%1)\n" /* %4 = ptr + 255 */
  72                 "  "LHI"  %3,-4096\n"
  73                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
  74                 "  "SLR"  %4,%1\n"
  75                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
  76                 "   jnh   3f\n"
  77                 "2: mvcp  0(%4,%2),0(%1),%3\n"
  78                 "  "SLR"  %0,%4\n"
  79                 "3:\n"
  80                 EX_TABLE(0b,1b) EX_TABLE(2b,3b)
  81                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  82                 : : "cc", "memory");
  83         return size;
  84 }
  85
  86 size_t copy_to_user_std(size_t size, void __user *ptr, const void *x)
  87 {
  88         unsigned long tmp1, tmp2;
  89
  90         tmp1 = -256UL;
  91         asm volatile(
  92                 "0: mvcs  0(%0,%1),0(%2),%3\n"
  93                 "   jz    5f\n"
  94                 "1:"ALR"  %0,%3\n"
  95                 "   la    %1,256(%1)\n"
  96                 "   la    %2,256(%2)\n"
  97                 "2: mvcs  0(%0,%1),0(%2),%3\n"
  98                 "   jnz   1b\n"
  99                 "   j     5f\n"
 100                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
 101                 "  "LHI"  %3,-4096\n"
 102                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
 103                 "  "SLR"  %4,%1\n"
 104                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
 105                 "   jnh   6f\n"
 106                 "4: mvcs  0(%4,%1),0(%2),%3\n"
 107                 "  "SLR"  %0,%4\n"
 108                 "   j     6f\n"
 109                 "5:"SLR"  %0,%0\n"
 110                 "6: \n"
 111                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
 112                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 113                 : : "cc", "memory");
 114         return size;
 115 }
 116
 117 size_t copy_to_user_std_small(size_t size, void __user *ptr, const void *x)
 118 {
 119         unsigned long tmp1, tmp2;
 120
 121         tmp1 = 0UL;
 122         asm volatile(
 123                 "0: mvcs  0(%0,%1),0(%2),%3\n"
 124                 "  "SLR"  %0,%0\n"
 125                 "   j     3f\n"
 126                 "1: la    %4,255(%1)\n" /* ptr + 255 */
 127                 "  "LHI"  %3,-4096\n"
 128                 "   nr    %4,%3\n"      /* (ptr + 255) & -4096UL */
 129                 "  "SLR"  %4,%1\n"
 130                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
 131                 "   jnh   3f\n"
 132                 "2: mvcs  0(%4,%1),0(%2),%3\n"
 133                 "  "SLR"  %0,%4\n"
 134                 "3:\n"
 135                 EX_TABLE(0b,1b) EX_TABLE(2b,3b)
 136                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 137                 : : "cc", "memory");
 138         return size;
 139 }
 140
 141 size_t copy_in_user_std(size_t size, void __user *to, const void __user *from)
 142 {
 143         unsigned long tmp1;
 144
 145         asm volatile(
 146                 "  "AHI"  %0,-1\n"
 147                 "   jo    5f\n"
 148                 "   sacf  256\n"
 149                 "   bras  %3,3f\n"
 150                 "0:"AHI"  %0,257\n"
 151                 "1: mvc   0(1,%1),0(%2)\n"
 152                 "   la    %1,1(%1)\n"
 153                 "   la    %2,1(%2)\n"
 154                 "  "AHI"  %0,-1\n"
 155                 "   jnz   1b\n"
 156                 "   j     5f\n"
 157                 "2: mvc   0(256,%1),0(%2)\n"
 158                 "   la    %1,256(%1)\n"
 159                 "   la    %2,256(%2)\n"
 160                 "3:"AHI"  %0,-256\n"
 161                 "   jnm   2b\n"
 162                 "4: ex    %0,1b-0b(%3)\n"
 163                 "   sacf  0\n"
 164                 "5: "SLR"  %0,%0\n"
 165                 "6:\n"
 166                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 167                 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
 168                 : : "cc", "memory");
 169         return size;
 170 }
 171
 172 size_t clear_user_std(size_t size, void __user *to)
 173 {
 174         unsigned long tmp1, tmp2;
 175
 176         asm volatile(
 177                 "  "AHI"  %0,-1\n"
 178                 "   jo    5f\n"
 179                 "   sacf  256\n"
 180                 "   bras  %3,3f\n"
 181                 "   xc    0(1,%1),0(%1)\n"
 182                 "0:"AHI"  %0,257\n"
 183                 "   la    %2,255(%1)\n" /* %2 = ptr + 255 */
 184                 "   srl   %2,12\n"
 185                 "   sll   %2,12\n"      /* %2 = (ptr + 255) & -4096 */
 186                 "  "SLR"  %2,%1\n"
 187                 "  "CLR"  %0,%2\n"      /* clear crosses next page boundary? */
 188                 "   jnh   5f\n"
 189                 "  "AHI"  %2,-1\n"
 190                 "1: ex    %2,0(%3)\n"
 191                 "  "AHI"  %2,1\n"
 192                 "  "SLR"  %0,%2\n"
 193                 "   j     5f\n"
 194                 "2: xc    0(256,%1),0(%1)\n"
 195                 "   la    %1,256(%1)\n"
 196                 "3:"AHI"  %0,-256\n"
 197                 "   jnm   2b\n"
 198                 "4: ex    %0,0(%3)\n"
 199                 "   sacf  0\n"
 200                 "5: "SLR"  %0,%0\n"
 201                 "6:\n"
 202                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 203                 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
 204                 : : "cc", "memory");
 205         return size;
 206 }
 207
 208 size_t strnlen_user_std(size_t size, const char __user *src)
 209 {
 210         register unsigned long reg0 asm("0") = 0UL;
 211         unsigned long tmp1, tmp2;
 212
 213         asm volatile(
 214                 "   la    %2,0(%1)\n"
 215                 "   la    %3,0(%0,%1)\n"
 216                 "  "SLR"  %0,%0\n"
 217                 "   sacf  256\n"
 218                 "0: srst  %3,%2\n"
 219                 "   jo    0b\n"
 220                 "   la    %0,1(%3)\n"   /* strnlen_user results includes \0 */
 221                 "  "SLR"  %0,%1\n"
 222                 "1: sacf  0\n"
 223                 EX_TABLE(0b,1b)
 224                 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
 225                 : "d" (reg0) : "cc", "memory");
 226         return size;
 227 }
 228
 229 size_t strncpy_from_user_std(size_t size, const char __user *src, char *dst)
 230 {
 231         register unsigned long reg0 asm("0") = 0UL;
 232         unsigned long tmp1, tmp2;
 233
 234         asm volatile(
 235                 "   la    %3,0(%1)\n"
 236                 "   la    %4,0(%0,%1)\n"
 237                 "   sacf  256\n"
 238                 "0: srst  %4,%3\n"
 239                 "   jo    0b\n"
 240                 "   sacf  0\n"
 241                 "   la    %0,0(%4)\n"
 242                 "   jh    1f\n"         /* found \0 in string ? */
 243                 "  "AHI"  %4,1\n"       /* include \0 in copy */
 244                 "1:"SLR"  %0,%1\n"      /* %0 = return length (without \0) */
 245                 "  "SLR"  %4,%1\n"      /* %4 = copy length (including \0) */
 246                 "2: mvcp  0(%4,%2),0(%1),%5\n"
 247                 "   jz    9f\n"
 248                 "3:"AHI"  %4,-256\n"
 249                 "   la    %1,256(%1)\n"
 250                 "   la    %2,256(%2)\n"
 251                 "4: mvcp  0(%4,%2),0(%1),%5\n"
 252                 "   jnz   3b\n"
 253                 "   j     9f\n"
 254                 "7: sacf  0\n"
 255                 "8:"LHI"  %0,%6\n"
 256                 "9:\n"
 257                 EX_TABLE(0b,7b) EX_TABLE(2b,8b) EX_TABLE(4b,8b)
 258                 : "+a" (size), "+a" (src), "+d" (dst), "=a" (tmp1), "=a" (tmp2)
 259                 : "d" (reg0), "K" (-EFAULT) : "cc", "memory");
 260         return size;
 261 }
 262
 263 #define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)      \
 264         asm volatile(                                                   \
 265                 "   sacf  256\n"                                        \
 266                 "0: l     %1,0(%6)\n"                                   \
 267                 "1:"insn                                                \
 268                 "2: cs    %1,%2,0(%6)\n"                                \
 269                 "3: jl    1b\n"                                         \
 270                 "   lhi   %0,0\n"                                       \
 271                 "4: sacf  0\n"                                          \
 272                 EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b)         \
 273                 : "=d" (ret), "=&d" (oldval), "=&d" (newval),           \
 274                   "=m" (*uaddr)                                         \
 275                 : "0" (-EFAULT), "d" (oparg), "a" (uaddr),              \
 276                   "m" (*uaddr) : "cc");
 277
 278 int futex_atomic_op(int op, int __user *uaddr, int oparg, int *old)
 279 {
 280         int oldval = 0, newval, ret;
 281
 282         inc_preempt_count();
 283
 284         switch (op) {
 285         case FUTEX_OP_SET:
 286                 __futex_atomic_op("lr %2,%5\n",
 287                                   ret, oldval, newval, uaddr, oparg);
 288                 break;
 289         case FUTEX_OP_ADD:
 290                 __futex_atomic_op("lr %2,%1\nar %2,%5\n",
 291                                   ret, oldval, newval, uaddr, oparg);
 292                 break;
 293         case FUTEX_OP_OR:
 294                 __futex_atomic_op("lr %2,%1\nor %2,%5\n",
 295                                   ret, oldval, newval, uaddr, oparg);
 296                 break;
 297         case FUTEX_OP_ANDN:
 298                 __futex_atomic_op("lr %2,%1\nnr %2,%5\n",
 299                                   ret, oldval, newval, uaddr, oparg);
 300                 break;
 301         case FUTEX_OP_XOR:
 302                 __futex_atomic_op("lr %2,%1\nxr %2,%5\n",
 303                                   ret, oldval, newval, uaddr, oparg);
 304                 break;
 305         default:
 306                 ret = -ENOSYS;
 307         }
 308         dec_preempt_count();
 309         *old = oldval;
 310         return ret;
 311 }
 312
 313 int futex_atomic_cmpxchg(int __user *uaddr, int oldval, int newval)
 314 {
 315         int ret;
 316
 317         asm volatile(
 318                 "   sacf 256\n"
 319                 "   cs   %1,%4,0(%5)\n"
 320                 "0: lr   %0,%1\n"
 321                 "1: sacf 0\n"
 322                 EX_TABLE(0b,1b)
 323                 : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
 324                 : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
 325                 : "cc", "memory" );
 326         return ret;
 327 }
 328
 329 struct uaccess_ops uaccess_std = {
 330         .copy_from_user = copy_from_user_std,
 331         .copy_from_user_small = copy_from_user_std_small,
 332         .copy_to_user = copy_to_user_std,
 333         .copy_to_user_small = copy_to_user_std_small,
 334         .copy_in_user = copy_in_user_std,
 335         .clear_user = clear_user_std,
 336         .strnlen_user = strnlen_user_std,
 337         .strncpy_from_user = strncpy_from_user_std,
 338         .futex_atomic_op = futex_atomic_op,
 339         .futex_atomic_cmpxchg = futex_atomic_cmpxchg,
 340 };