linux/arch/s390/lib/uaccess_std.c
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   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
  30size_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
  72static 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
  80size_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
 112static 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
 120static 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
 151static 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
 186size_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
 209size_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
 244int 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
 276int 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
 294struct 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};
 306