arch/s390/lib/uaccess_std.c

   1 /*
   2  *  Standard user space access functions based on mvcp/mvcs and doing
   3  *  interesting things in the secondary space mode.
   4  *
   5  *    Copyright IBM Corp. 2006
   6  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   7  *               Gerald Schaefer (gerald.schaefer@de.ibm.com)
   8  */
   9
  10 #include <linux/errno.h>
  11 #include <linux/mm.h>
  12 #include <linux/uaccess.h>
  13 #include <asm/futex.h>
  14 #include "uaccess.h"
  15
  16 #ifndef CONFIG_64BIT
  17 #define AHI     "ahi"
  18 #define ALR     "alr"
  19 #define CLR     "clr"
  20 #define LHI     "lhi"
  21 #define SLR     "slr"
  22 #else
  23 #define AHI     "aghi"
  24 #define ALR     "algr"
  25 #define CLR     "clgr"
  26 #define LHI     "lghi"
  27 #define SLR     "slgr"
  28 #endif
  29
  30 size_t copy_from_user_std(size_t size, const void __user *ptr, void *x)
  31 {
  32         unsigned long tmp1, tmp2;
  33
  34         tmp1 = -256UL;
  35         asm volatile(
  36                 "0: mvcp  0(%0,%2),0(%1),%3\n"
  37                 "10:jz    8f\n"
  38                 "1:"ALR"  %0,%3\n"
  39                 "   la    %1,256(%1)\n"
  40                 "   la    %2,256(%2)\n"
  41                 "2: mvcp  0(%0,%2),0(%1),%3\n"
  42                 "11:jnz   1b\n"
  43                 "   j     8f\n"
  44                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
  45                 "  "LHI"  %3,-4096\n"
  46                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
  47                 "  "SLR"  %4,%1\n"
  48                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
  49                 "   jnh   5f\n"
  50                 "4: mvcp  0(%4,%2),0(%1),%3\n"
  51                 "12:"SLR"  %0,%4\n"
  52                 "  "ALR"  %2,%4\n"
  53                 "5:"LHI"  %4,-1\n"
  54                 "  "ALR"  %4,%0\n"      /* copy remaining size, subtract 1 */
  55                 "   bras  %3,7f\n"      /* memset loop */
  56                 "   xc    0(1,%2),0(%2)\n"
  57                 "6: xc    0(256,%2),0(%2)\n"
  58                 "   la    %2,256(%2)\n"
  59                 "7:"AHI"  %4,-256\n"
  60                 "   jnm   6b\n"
  61                 "   ex    %4,0(%3)\n"
  62                 "   j     9f\n"
  63                 "8:"SLR"  %0,%0\n"
  64                 "9: \n"
  65                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b)
  66                 EX_TABLE(10b,3b) EX_TABLE(11b,3b) EX_TABLE(12b,5b)
  67                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  68                 : : "cc", "memory");
  69         return size;
  70 }
  71
  72 static size_t copy_from_user_std_check(size_t size, const void __user *ptr,
  73                                        void *x)
  74 {
  75         if (size <= 1024)
  76                 return copy_from_user_std(size, ptr, x);
  77         return copy_from_user_pt(size, ptr, x);
  78 }
  79
  80 size_t copy_to_user_std(size_t size, void __user *ptr, const void *x)
  81 {
  82         unsigned long tmp1, tmp2;
  83
  84         tmp1 = -256UL;
  85         asm volatile(
  86                 "0: mvcs  0(%0,%1),0(%2),%3\n"
  87                 "7: jz    5f\n"
  88                 "1:"ALR"  %0,%3\n"
  89                 "   la    %1,256(%1)\n"
  90                 "   la    %2,256(%2)\n"
  91                 "2: mvcs  0(%0,%1),0(%2),%3\n"
  92                 "8: jnz   1b\n"
  93                 "   j     5f\n"
  94                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
  95                 "  "LHI"  %3,-4096\n"
  96                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
  97                 "  "SLR"  %4,%1\n"
  98                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
  99                 "   jnh   6f\n"
 100                 "4: mvcs  0(%4,%1),0(%2),%3\n"
 101                 "9:"SLR"  %0,%4\n"
 102                 "   j     6f\n"
 103                 "5:"SLR"  %0,%0\n"
 104                 "6: \n"
 105                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
 106                 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
 107                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 108                 : : "cc", "memory");
 109         return size;
 110 }
 111
 112 static size_t copy_to_user_std_check(size_t size, void __user *ptr,
 113                                      const void *x)
 114 {
 115         if (size <= 1024)
 116                 return copy_to_user_std(size, ptr, x);
 117         return copy_to_user_pt(size, ptr, x);
 118 }
 119
 120 static size_t copy_in_user_std(size_t size, void __user *to,
 121                                const void __user *from)
 122 {
 123         unsigned long tmp1;
 124
 125         asm volatile(
 126                 "   sacf  256\n"
 127                 "  "AHI"  %0,-1\n"
 128                 "   jo    5f\n"
 129                 "   bras  %3,3f\n"
 130                 "0:"AHI"  %0,257\n"
 131                 "1: mvc   0(1,%1),0(%2)\n"
 132                 "   la    %1,1(%1)\n"
 133                 "   la    %2,1(%2)\n"
 134                 "  "AHI"  %0,-1\n"
 135                 "   jnz   1b\n"
 136                 "   j     5f\n"
 137                 "2: mvc   0(256,%1),0(%2)\n"
 138                 "   la    %1,256(%1)\n"
 139                 "   la    %2,256(%2)\n"
 140                 "3:"AHI"  %0,-256\n"
 141                 "   jnm   2b\n"
 142                 "4: ex    %0,1b-0b(%3)\n"
 143                 "5: "SLR"  %0,%0\n"
 144                 "6: sacf  0\n"
 145                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 146                 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
 147                 : : "cc", "memory");
 148         return size;
 149 }
 150
 151 static size_t clear_user_std(size_t size, void __user *to)
 152 {
 153         unsigned long tmp1, tmp2;
 154
 155         asm volatile(
 156                 "   sacf  256\n"
 157                 "  "AHI"  %0,-1\n"
 158                 "   jo    5f\n"
 159                 "   bras  %3,3f\n"
 160                 "   xc    0(1,%1),0(%1)\n"
 161                 "0:"AHI"  %0,257\n"
 162                 "   la    %2,255(%1)\n" /* %2 = ptr + 255 */
 163                 "   srl   %2,12\n"
 164                 "   sll   %2,12\n"      /* %2 = (ptr + 255) & -4096 */
 165                 "  "SLR"  %2,%1\n"
 166                 "  "CLR"  %0,%2\n"      /* clear crosses next page boundary? */
 167                 "   jnh   5f\n"
 168                 "  "AHI"  %2,-1\n"
 169                 "1: ex    %2,0(%3)\n"
 170                 "  "AHI"  %2,1\n"
 171                 "  "SLR"  %0,%2\n"
 172                 "   j     5f\n"
 173                 "2: xc    0(256,%1),0(%1)\n"
 174                 "   la    %1,256(%1)\n"
 175                 "3:"AHI"  %0,-256\n"
 176                 "   jnm   2b\n"
 177                 "4: ex    %0,0(%3)\n"
 178                 "5: "SLR"  %0,%0\n"
 179                 "6: sacf  0\n"
 180                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 181                 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
 182                 : : "cc", "memory");
 183         return size;
 184 }
 185
 186 size_t strnlen_user_std(size_t size, const char __user *src)
 187 {
 188         register unsigned long reg0 asm("0") = 0UL;
 189         unsigned long tmp1, tmp2;
 190
 191         if (unlikely(!size))
 192                 return 0;
 193         asm volatile(
 194                 "   la    %2,0(%1)\n"
 195                 "   la    %3,0(%0,%1)\n"
 196                 "  "SLR"  %0,%0\n"
 197                 "   sacf  256\n"
 198                 "0: srst  %3,%2\n"
 199                 "   jo    0b\n"
 200                 "   la    %0,1(%3)\n"   /* strnlen_user results includes \0 */
 201                 "  "SLR"  %0,%1\n"
 202                 "1: sacf  0\n"
 203                 EX_TABLE(0b,1b)
 204                 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
 205                 : "d" (reg0) : "cc", "memory");
 206         return size;
 207 }
 208
 209 size_t strncpy_from_user_std(size_t count, const char __user *src, char *dst)
 210 {
 211         size_t done, len, offset, len_str;
 212
 213         if (unlikely(!count))
 214                 return 0;
 215         done = 0;
 216         do {
 217                 offset = (size_t)src & ~PAGE_MASK;
 218                 len = min(count - done, PAGE_SIZE - offset);
 219                 if (copy_from_user_std(len, src, dst))
 220                         return -EFAULT;
 221                 len_str = strnlen(dst, len);
 222                 done += len_str;
 223                 src += len_str;
 224                 dst += len_str;
 225         } while ((len_str == len) && (done < count));
 226         return done;
 227 }
 228
 229 #define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)      \
 230         asm volatile(                                                   \
 231                 "   sacf  256\n"                                        \
 232                 "0: l     %1,0(%6)\n"                                   \
 233                 "1:"insn                                                \
 234                 "2: cs    %1,%2,0(%6)\n"                                \
 235                 "3: jl    1b\n"                                         \
 236                 "   lhi   %0,0\n"                                       \
 237                 "4: sacf  0\n"                                          \
 238                 EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b)         \
 239                 : "=d" (ret), "=&d" (oldval), "=&d" (newval),           \
 240                   "=m" (*uaddr)                                         \
 241                 : "0" (-EFAULT), "d" (oparg), "a" (uaddr),              \
 242                   "m" (*uaddr) : "cc");
 243
 244 int futex_atomic_op_std(int op, u32 __user *uaddr, int oparg, int *old)
 245 {
 246         int oldval = 0, newval, ret;
 247
 248         switch (op) {
 249         case FUTEX_OP_SET:
 250                 __futex_atomic_op("lr %2,%5\n",
 251                                   ret, oldval, newval, uaddr, oparg);
 252                 break;
 253         case FUTEX_OP_ADD:
 254                 __futex_atomic_op("lr %2,%1\nar %2,%5\n",
 255                                   ret, oldval, newval, uaddr, oparg);
 256                 break;
 257         case FUTEX_OP_OR:
 258                 __futex_atomic_op("lr %2,%1\nor %2,%5\n",
 259                                   ret, oldval, newval, uaddr, oparg);
 260                 break;
 261         case FUTEX_OP_ANDN:
 262                 __futex_atomic_op("lr %2,%1\nnr %2,%5\n",
 263                                   ret, oldval, newval, uaddr, oparg);
 264                 break;
 265         case FUTEX_OP_XOR:
 266                 __futex_atomic_op("lr %2,%1\nxr %2,%5\n",
 267                                   ret, oldval, newval, uaddr, oparg);
 268                 break;
 269         default:
 270                 ret = -ENOSYS;
 271         }
 272         *old = oldval;
 273         return ret;
 274 }
 275
 276 int futex_atomic_cmpxchg_std(u32 *uval, u32 __user *uaddr,
 277                              u32 oldval, u32 newval)
 278 {
 279         int ret;
 280
 281         asm volatile(
 282                 "   sacf 256\n"
 283                 "0: cs   %1,%4,0(%5)\n"
 284                 "1: la   %0,0\n"
 285                 "2: sacf 0\n"
 286                 EX_TABLE(0b,2b) EX_TABLE(1b,2b)
 287                 : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
 288                 : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
 289                 : "cc", "memory" );
 290         *uval = oldval;
 291         return ret;
 292 }
 293
 294 struct uaccess_ops uaccess_std = {
 295         .copy_from_user = copy_from_user_std_check,
 296         .copy_from_user_small = copy_from_user_std,
 297         .copy_to_user = copy_to_user_std_check,
 298         .copy_to_user_small = copy_to_user_std,
 299         .copy_in_user = copy_in_user_std,
 300         .clear_user = clear_user_std,
 301         .strnlen_user = strnlen_user_std,
 302         .strncpy_from_user = strncpy_from_user_std,
 303         .futex_atomic_op = futex_atomic_op_std,
 304         .futex_atomic_cmpxchg = futex_atomic_cmpxchg_std,
 305 };