linux/arch/s390/lib/uaccess_std.c
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   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
  32size_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                "10: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                "11: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                "12:"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                EX_TABLE(10b,3b) EX_TABLE(11b,3b) EX_TABLE(12b,5b)
  69                : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  70                : : "cc", "memory");
  71        return size;
  72}
  73
  74static size_t copy_from_user_std_check(size_t size, const void __user *ptr,
  75                                       void *x)
  76{
  77        if (size <= 1024)
  78                return copy_from_user_std(size, ptr, x);
  79        return copy_from_user_pt(size, ptr, x);
  80}
  81
  82size_t copy_to_user_std(size_t size, void __user *ptr, const void *x)
  83{
  84        unsigned long tmp1, tmp2;
  85
  86        tmp1 = -256UL;
  87        asm volatile(
  88                "0: mvcs  0(%0,%1),0(%2),%3\n"
  89                "7: jz    5f\n"
  90                "1:"ALR"  %0,%3\n"
  91                "   la    %1,256(%1)\n"
  92                "   la    %2,256(%2)\n"
  93                "2: mvcs  0(%0,%1),0(%2),%3\n"
  94                "8: jnz   1b\n"
  95                "   j     5f\n"
  96                "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
  97                "  "LHI"  %3,-4096\n"
  98                "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
  99                "  "SLR"  %4,%1\n"
 100                "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
 101                "   jnh   6f\n"
 102                "4: mvcs  0(%4,%1),0(%2),%3\n"
 103                "9:"SLR"  %0,%4\n"
 104                "   j     6f\n"
 105                "5:"SLR"  %0,%0\n"
 106                "6: \n"
 107                EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
 108                EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
 109                : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 110                : : "cc", "memory");
 111        return size;
 112}
 113
 114static size_t copy_to_user_std_check(size_t size, void __user *ptr,
 115                                     const void *x)
 116{
 117        if (size <= 1024)
 118                return copy_to_user_std(size, ptr, x);
 119        return copy_to_user_pt(size, ptr, x);
 120}
 121
 122static size_t copy_in_user_std(size_t size, void __user *to,
 123                               const void __user *from)
 124{
 125        unsigned long tmp1;
 126
 127        asm volatile(
 128                "  "AHI"  %0,-1\n"
 129                "   jo    5f\n"
 130                "   sacf  256\n"
 131                "   bras  %3,3f\n"
 132                "0:"AHI"  %0,257\n"
 133                "1: mvc   0(1,%1),0(%2)\n"
 134                "   la    %1,1(%1)\n"
 135                "   la    %2,1(%2)\n"
 136                "  "AHI"  %0,-1\n"
 137                "   jnz   1b\n"
 138                "   j     5f\n"
 139                "2: mvc   0(256,%1),0(%2)\n"
 140                "   la    %1,256(%1)\n"
 141                "   la    %2,256(%2)\n"
 142                "3:"AHI"  %0,-256\n"
 143                "   jnm   2b\n"
 144                "4: ex    %0,1b-0b(%3)\n"
 145                "   sacf  0\n"
 146                "5: "SLR"  %0,%0\n"
 147                "6:\n"
 148                EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 149                : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
 150                : : "cc", "memory");
 151        return size;
 152}
 153
 154static size_t clear_user_std(size_t size, void __user *to)
 155{
 156        unsigned long tmp1, tmp2;
 157
 158        asm volatile(
 159                "  "AHI"  %0,-1\n"
 160                "   jo    5f\n"
 161                "   sacf  256\n"
 162                "   bras  %3,3f\n"
 163                "   xc    0(1,%1),0(%1)\n"
 164                "0:"AHI"  %0,257\n"
 165                "   la    %2,255(%1)\n" /* %2 = ptr + 255 */
 166                "   srl   %2,12\n"
 167                "   sll   %2,12\n"      /* %2 = (ptr + 255) & -4096 */
 168                "  "SLR"  %2,%1\n"
 169                "  "CLR"  %0,%2\n"      /* clear crosses next page boundary? */
 170                "   jnh   5f\n"
 171                "  "AHI"  %2,-1\n"
 172                "1: ex    %2,0(%3)\n"
 173                "  "AHI"  %2,1\n"
 174                "  "SLR"  %0,%2\n"
 175                "   j     5f\n"
 176                "2: xc    0(256,%1),0(%1)\n"
 177                "   la    %1,256(%1)\n"
 178                "3:"AHI"  %0,-256\n"
 179                "   jnm   2b\n"
 180                "4: ex    %0,0(%3)\n"
 181                "   sacf  0\n"
 182                "5: "SLR"  %0,%0\n"
 183                "6:\n"
 184                EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 185                : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
 186                : : "cc", "memory");
 187        return size;
 188}
 189
 190size_t strnlen_user_std(size_t size, const char __user *src)
 191{
 192        register unsigned long reg0 asm("0") = 0UL;
 193        unsigned long tmp1, tmp2;
 194
 195        asm volatile(
 196                "   la    %2,0(%1)\n"
 197                "   la    %3,0(%0,%1)\n"
 198                "  "SLR"  %0,%0\n"
 199                "   sacf  256\n"
 200                "0: srst  %3,%2\n"
 201                "   jo    0b\n"
 202                "   la    %0,1(%3)\n"   /* strnlen_user results includes \0 */
 203                "  "SLR"  %0,%1\n"
 204                "1: sacf  0\n"
 205                EX_TABLE(0b,1b)
 206                : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
 207                : "d" (reg0) : "cc", "memory");
 208        return size;
 209}
 210
 211size_t strncpy_from_user_std(size_t size, const char __user *src, char *dst)
 212{
 213        register unsigned long reg0 asm("0") = 0UL;
 214        unsigned long tmp1, tmp2;
 215
 216        asm volatile(
 217                "   la    %3,0(%1)\n"
 218                "   la    %4,0(%0,%1)\n"
 219                "   sacf  256\n"
 220                "0: srst  %4,%3\n"
 221                "   jo    0b\n"
 222                "   sacf  0\n"
 223                "   la    %0,0(%4)\n"
 224                "   jh    1f\n"         /* found \0 in string ? */
 225                "  "AHI"  %4,1\n"       /* include \0 in copy */
 226                "1:"SLR"  %0,%1\n"      /* %0 = return length (without \0) */
 227                "  "SLR"  %4,%1\n"      /* %4 = copy length (including \0) */
 228                "2: mvcp  0(%4,%2),0(%1),%5\n"
 229                "   jz    9f\n"
 230                "3:"AHI"  %4,-256\n"
 231                "   la    %1,256(%1)\n"
 232                "   la    %2,256(%2)\n"
 233                "4: mvcp  0(%4,%2),0(%1),%5\n"
 234                "   jnz   3b\n"
 235                "   j     9f\n"
 236                "7: sacf  0\n"
 237                "8:"LHI"  %0,%6\n"
 238                "9:\n"
 239                EX_TABLE(0b,7b) EX_TABLE(2b,8b) EX_TABLE(4b,8b)
 240                : "+a" (size), "+a" (src), "+d" (dst), "=a" (tmp1), "=a" (tmp2)
 241                : "d" (reg0), "K" (-EFAULT) : "cc", "memory");
 242        return size;
 243}
 244
 245#define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)      \
 246        asm volatile(                                                   \
 247                "   sacf  256\n"                                        \
 248                "0: l     %1,0(%6)\n"                                   \
 249                "1:"insn                                                \
 250                "2: cs    %1,%2,0(%6)\n"                                \
 251                "3: jl    1b\n"                                         \
 252                "   lhi   %0,0\n"                                       \
 253                "4: sacf  0\n"                                          \
 254                EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b)         \
 255                : "=d" (ret), "=&d" (oldval), "=&d" (newval),           \
 256                  "=m" (*uaddr)                                         \
 257                : "0" (-EFAULT), "d" (oparg), "a" (uaddr),              \
 258                  "m" (*uaddr) : "cc");
 259
 260int futex_atomic_op_std(int op, int __user *uaddr, int oparg, int *old)
 261{
 262        int oldval = 0, newval, ret;
 263
 264        switch (op) {
 265        case FUTEX_OP_SET:
 266                __futex_atomic_op("lr %2,%5\n",
 267                                  ret, oldval, newval, uaddr, oparg);
 268                break;
 269        case FUTEX_OP_ADD:
 270                __futex_atomic_op("lr %2,%1\nar %2,%5\n",
 271                                  ret, oldval, newval, uaddr, oparg);
 272                break;
 273        case FUTEX_OP_OR:
 274                __futex_atomic_op("lr %2,%1\nor %2,%5\n",
 275                                  ret, oldval, newval, uaddr, oparg);
 276                break;
 277        case FUTEX_OP_ANDN:
 278                __futex_atomic_op("lr %2,%1\nnr %2,%5\n",
 279                                  ret, oldval, newval, uaddr, oparg);
 280                break;
 281        case FUTEX_OP_XOR:
 282                __futex_atomic_op("lr %2,%1\nxr %2,%5\n",
 283                                  ret, oldval, newval, uaddr, oparg);
 284                break;
 285        default:
 286                ret = -ENOSYS;
 287        }
 288        *old = oldval;
 289        return ret;
 290}
 291
 292int futex_atomic_cmpxchg_std(int __user *uaddr, int oldval, int newval)
 293{
 294        int ret;
 295
 296        asm volatile(
 297                "   sacf 256\n"
 298                "0: cs   %1,%4,0(%5)\n"
 299                "1: lr   %0,%1\n"
 300                "2: sacf 0\n"
 301                EX_TABLE(0b,2b) EX_TABLE(1b,2b)
 302                : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
 303                : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
 304                : "cc", "memory" );
 305        return ret;
 306}
 307
 308struct uaccess_ops uaccess_std = {
 309        .copy_from_user = copy_from_user_std_check,
 310        .copy_from_user_small = copy_from_user_std,
 311        .copy_to_user = copy_to_user_std_check,
 312        .copy_to_user_small = copy_to_user_std,
 313        .copy_in_user = copy_in_user_std,
 314        .clear_user = clear_user_std,
 315        .strnlen_user = strnlen_user_std,
 316        .strncpy_from_user = strncpy_from_user_std,
 317        .futex_atomic_op = futex_atomic_op_std,
 318        .futex_atomic_cmpxchg = futex_atomic_cmpxchg_std,
 319};
 320