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 <linux/uaccess.h>
  15 #include <asm/futex.h>
  16 #include "uaccess.h"
  17
  18 #ifndef __s390x__
  19 #define AHI     "ahi"
  20 #define ALR     "alr"
  21 #define CLR     "clr"
  22 #define LHI     "lhi"
  23 #define SLR     "slr"
  24 #else
  25 #define AHI     "aghi"
  26 #define ALR     "algr"
  27 #define CLR     "clgr"
  28 #define LHI     "lghi"
  29 #define SLR     "slgr"
  30 #endif
  31
  32 size_t copy_from_user_std(size_t size, const void __user *ptr, void *x)
  33 {
  34         unsigned long tmp1, tmp2;
  35
  36         tmp1 = -256UL;
  37         asm volatile(
  38                 "0: mvcp  0(%0,%2),0(%1),%3\n"
  39                 "   jz    8f\n"
  40                 "1:"ALR"  %0,%3\n"
  41                 "   la    %1,256(%1)\n"
  42                 "   la    %2,256(%2)\n"
  43                 "2: mvcp  0(%0,%2),0(%1),%3\n"
  44                 "   jnz   1b\n"
  45                 "   j     8f\n"
  46                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
  47                 "  "LHI"  %3,-4096\n"
  48                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
  49                 "  "SLR"  %4,%1\n"
  50                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
  51                 "   jnh   5f\n"
  52                 "4: mvcp  0(%4,%2),0(%1),%3\n"
  53                 "  "SLR"  %0,%4\n"
  54                 "  "ALR"  %2,%4\n"
  55                 "5:"LHI"  %4,-1\n"
  56                 "  "ALR"  %4,%0\n"      /* copy remaining size, subtract 1 */
  57                 "   bras  %3,7f\n"      /* memset loop */
  58                 "   xc    0(1,%2),0(%2)\n"
  59                 "6: xc    0(256,%2),0(%2)\n"
  60                 "   la    %2,256(%2)\n"
  61                 "7:"AHI"  %4,-256\n"
  62                 "   jnm   6b\n"
  63                 "   ex    %4,0(%3)\n"
  64                 "   j     9f\n"
  65                 "8:"SLR"  %0,%0\n"
  66                 "9: \n"
  67                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b)
  68                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  69                 : : "cc", "memory");
  70         return size;
  71 }
  72
  73 static size_t copy_from_user_std_check(size_t size, const void __user *ptr,
  74                                        void *x)
  75 {
  76         if (size <= 1024)
  77                 return copy_from_user_std(size, ptr, x);
  78         return copy_from_user_pt(size, ptr, x);
  79 }
  80
  81 size_t copy_to_user_std(size_t size, void __user *ptr, const void *x)
  82 {
  83         unsigned long tmp1, tmp2;
  84
  85         tmp1 = -256UL;
  86         asm volatile(
  87                 "0: mvcs  0(%0,%1),0(%2),%3\n"
  88                 "   jz    5f\n"
  89                 "1:"ALR"  %0,%3\n"
  90                 "   la    %1,256(%1)\n"
  91                 "   la    %2,256(%2)\n"
  92                 "2: mvcs  0(%0,%1),0(%2),%3\n"
  93                 "   jnz   1b\n"
  94                 "   j     5f\n"
  95                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
  96                 "  "LHI"  %3,-4096\n"
  97                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
  98                 "  "SLR"  %4,%1\n"
  99                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
 100                 "   jnh   6f\n"
 101                 "4: mvcs  0(%4,%1),0(%2),%3\n"
 102                 "  "SLR"  %0,%4\n"
 103                 "   j     6f\n"
 104                 "5:"SLR"  %0,%0\n"
 105                 "6: \n"
 106                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,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                 "  "AHI"  %0,-1\n"
 127                 "   jo    5f\n"
 128                 "   sacf  256\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                 "   sacf  0\n"
 144                 "5: "SLR"  %0,%0\n"
 145                 "6:\n"
 146                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 147                 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
 148                 : : "cc", "memory");
 149         return size;
 150 }
 151
 152 static size_t clear_user_std(size_t size, void __user *to)
 153 {
 154         unsigned long tmp1, tmp2;
 155
 156         asm volatile(
 157                 "  "AHI"  %0,-1\n"
 158                 "   jo    5f\n"
 159                 "   sacf  256\n"
 160                 "   bras  %3,3f\n"
 161                 "   xc    0(1,%1),0(%1)\n"
 162                 "0:"AHI"  %0,257\n"
 163                 "   la    %2,255(%1)\n" /* %2 = ptr + 255 */
 164                 "   srl   %2,12\n"
 165                 "   sll   %2,12\n"      /* %2 = (ptr + 255) & -4096 */
 166                 "  "SLR"  %2,%1\n"
 167                 "  "CLR"  %0,%2\n"      /* clear crosses next page boundary? */
 168                 "   jnh   5f\n"
 169                 "  "AHI"  %2,-1\n"
 170                 "1: ex    %2,0(%3)\n"
 171                 "  "AHI"  %2,1\n"
 172                 "  "SLR"  %0,%2\n"
 173                 "   j     5f\n"
 174                 "2: xc    0(256,%1),0(%1)\n"
 175                 "   la    %1,256(%1)\n"
 176                 "3:"AHI"  %0,-256\n"
 177                 "   jnm   2b\n"
 178                 "4: ex    %0,0(%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" (tmp1), "=a" (tmp2)
 184                 : : "cc", "memory");
 185         return size;
 186 }
 187
 188 size_t strnlen_user_std(size_t size, const char __user *src)
 189 {
 190         register unsigned long reg0 asm("0") = 0UL;
 191         unsigned long tmp1, tmp2;
 192
 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 size, const char __user *src, char *dst)
 210 {
 211         register unsigned long reg0 asm("0") = 0UL;
 212         unsigned long tmp1, tmp2;
 213
 214         asm volatile(
 215                 "   la    %3,0(%1)\n"
 216                 "   la    %4,0(%0,%1)\n"
 217                 "   sacf  256\n"
 218                 "0: srst  %4,%3\n"
 219                 "   jo    0b\n"
 220                 "   sacf  0\n"
 221                 "   la    %0,0(%4)\n"
 222                 "   jh    1f\n"         /* found \0 in string ? */
 223                 "  "AHI"  %4,1\n"       /* include \0 in copy */
 224                 "1:"SLR"  %0,%1\n"      /* %0 = return length (without \0) */
 225                 "  "SLR"  %4,%1\n"      /* %4 = copy length (including \0) */
 226                 "2: mvcp  0(%4,%2),0(%1),%5\n"
 227                 "   jz    9f\n"
 228                 "3:"AHI"  %4,-256\n"
 229                 "   la    %1,256(%1)\n"
 230                 "   la    %2,256(%2)\n"
 231                 "4: mvcp  0(%4,%2),0(%1),%5\n"
 232                 "   jnz   3b\n"
 233                 "   j     9f\n"
 234                 "7: sacf  0\n"
 235                 "8:"LHI"  %0,%6\n"
 236                 "9:\n"
 237                 EX_TABLE(0b,7b) EX_TABLE(2b,8b) EX_TABLE(4b,8b)
 238                 : "+a" (size), "+a" (src), "+d" (dst), "=a" (tmp1), "=a" (tmp2)
 239                 : "d" (reg0), "K" (-EFAULT) : "cc", "memory");
 240         return size;
 241 }
 242
 243 #define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)      \
 244         asm volatile(                                                   \
 245                 "   sacf  256\n"                                        \
 246                 "0: l     %1,0(%6)\n"                                   \
 247                 "1:"insn                                                \
 248                 "2: cs    %1,%2,0(%6)\n"                                \
 249                 "3: jl    1b\n"                                         \
 250                 "   lhi   %0,0\n"                                       \
 251                 "4: sacf  0\n"                                          \
 252                 EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b)         \
 253                 : "=d" (ret), "=&d" (oldval), "=&d" (newval),           \
 254                   "=m" (*uaddr)                                         \
 255                 : "0" (-EFAULT), "d" (oparg), "a" (uaddr),              \
 256                   "m" (*uaddr) : "cc");
 257
 258 int futex_atomic_op_std(int op, int __user *uaddr, int oparg, int *old)
 259 {
 260         int oldval = 0, newval, ret;
 261
 262         switch (op) {
 263         case FUTEX_OP_SET:
 264                 __futex_atomic_op("lr %2,%5\n",
 265                                   ret, oldval, newval, uaddr, oparg);
 266                 break;
 267         case FUTEX_OP_ADD:
 268                 __futex_atomic_op("lr %2,%1\nar %2,%5\n",
 269                                   ret, oldval, newval, uaddr, oparg);
 270                 break;
 271         case FUTEX_OP_OR:
 272                 __futex_atomic_op("lr %2,%1\nor %2,%5\n",
 273                                   ret, oldval, newval, uaddr, oparg);
 274                 break;
 275         case FUTEX_OP_ANDN:
 276                 __futex_atomic_op("lr %2,%1\nnr %2,%5\n",
 277                                   ret, oldval, newval, uaddr, oparg);
 278                 break;
 279         case FUTEX_OP_XOR:
 280                 __futex_atomic_op("lr %2,%1\nxr %2,%5\n",
 281                                   ret, oldval, newval, uaddr, oparg);
 282                 break;
 283         default:
 284                 ret = -ENOSYS;
 285         }
 286         *old = oldval;
 287         return ret;
 288 }
 289
 290 int futex_atomic_cmpxchg_std(int __user *uaddr, int oldval, int newval)
 291 {
 292         int ret;
 293
 294         asm volatile(
 295                 "   sacf 256\n"
 296                 "0: cs   %1,%4,0(%5)\n"
 297                 "1: lr   %0,%1\n"
 298                 "2: sacf 0\n"
 299                 EX_TABLE(0b,2b) EX_TABLE(1b,2b)
 300                 : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
 301                 : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
 302                 : "cc", "memory" );
 303         return ret;
 304 }
 305
 306 struct uaccess_ops uaccess_std = {
 307         .copy_from_user = copy_from_user_std_check,
 308         .copy_from_user_small = copy_from_user_std,
 309         .copy_to_user = copy_to_user_std_check,
 310         .copy_to_user_small = copy_to_user_std,
 311         .copy_in_user = copy_in_user_std,
 312         .clear_user = clear_user_std,
 313         .strnlen_user = strnlen_user_std,
 314         .strncpy_from_user = strncpy_from_user_std,
 315         .futex_atomic_op = futex_atomic_op_std,
 316         .futex_atomic_cmpxchg = futex_atomic_cmpxchg_std,
 317 };