arch/s390/lib/uaccess_mvcos.c

   1 /*
   2  *  arch/s390/lib/uaccess_mvcos.c
   3  *
   4  *  Optimized user space space access functions based on mvcos.
   5  *
   6  *    Copyright (C) IBM Corp. 2006
   7  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   8  *               Gerald Schaefer (gerald.schaefer@de.ibm.com)
   9  */
  10
  11 #include <linux/errno.h>
  12 #include <linux/mm.h>
  13 #include <asm/uaccess.h>
  14 #include <asm/futex.h>
  15
  16 #ifndef __s390x__
  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 extern size_t copy_from_user_std(size_t, const void __user *, void *);
  31 extern size_t copy_to_user_std(size_t, void __user *, const void *);
  32
  33 size_t copy_from_user_mvcos(size_t size, const void __user *ptr, void *x)
  34 {
  35         register unsigned long reg0 asm("0") = 0x81UL;
  36         unsigned long tmp1, tmp2;
  37
  38         tmp1 = -4096UL;
  39         asm volatile(
  40                 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
  41                 "   jz    7f\n"
  42                 "1:"ALR"  %0,%3\n"
  43                 "  "SLR"  %1,%3\n"
  44                 "  "SLR"  %2,%3\n"
  45                 "   j     0b\n"
  46                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
  47                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
  48                 "  "SLR"  %4,%1\n"
  49                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
  50                 "   jnh   4f\n"
  51                 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
  52                 "  "SLR"  %0,%4\n"
  53                 "  "ALR"  %2,%4\n"
  54                 "4:"LHI"  %4,-1\n"
  55                 "  "ALR"  %4,%0\n"      /* copy remaining size, subtract 1 */
  56                 "   bras  %3,6f\n"      /* memset loop */
  57                 "   xc    0(1,%2),0(%2)\n"
  58                 "5: xc    0(256,%2),0(%2)\n"
  59                 "   la    %2,256(%2)\n"
  60                 "6:"AHI"  %4,-256\n"
  61                 "   jnm   5b\n"
  62                 "   ex    %4,0(%3)\n"
  63                 "   j     8f\n"
  64                 "7:"SLR"  %0,%0\n"
  65                 "8: \n"
  66                 EX_TABLE(0b,2b) EX_TABLE(3b,4b)
  67                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  68                 : "d" (reg0) : "cc", "memory");
  69         return size;
  70 }
  71
  72 size_t copy_from_user_mvcos_check(size_t size, const void __user *ptr, void *x)
  73 {
  74         if (size <= 256)
  75                 return copy_from_user_std(size, ptr, x);
  76         return copy_from_user_mvcos(size, ptr, x);
  77 }
  78
  79 size_t copy_to_user_mvcos(size_t size, void __user *ptr, const void *x)
  80 {
  81         register unsigned long reg0 asm("0") = 0x810000UL;
  82         unsigned long tmp1, tmp2;
  83
  84         tmp1 = -4096UL;
  85         asm volatile(
  86                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
  87                 "   jz    4f\n"
  88                 "1:"ALR"  %0,%3\n"
  89                 "  "SLR"  %1,%3\n"
  90                 "  "SLR"  %2,%3\n"
  91                 "   j     0b\n"
  92                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
  93                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
  94                 "  "SLR"  %4,%1\n"
  95                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
  96                 "   jnh   5f\n"
  97                 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
  98                 "  "SLR"  %0,%4\n"
  99                 "   j     5f\n"
 100                 "4:"SLR"  %0,%0\n"
 101                 "5: \n"
 102                 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
 103                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 104                 : "d" (reg0) : "cc", "memory");
 105         return size;
 106 }
 107
 108 size_t copy_to_user_mvcos_check(size_t size, void __user *ptr, const void *x)
 109 {
 110         if (size <= 256)
 111                 return copy_to_user_std(size, ptr, x);
 112         return copy_to_user_mvcos(size, ptr, x);
 113 }
 114
 115 size_t copy_in_user_mvcos(size_t size, void __user *to, const void __user *from)
 116 {
 117         register unsigned long reg0 asm("0") = 0x810081UL;
 118         unsigned long tmp1, tmp2;
 119
 120         tmp1 = -4096UL;
 121         /* FIXME: copy with reduced length. */
 122         asm volatile(
 123                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
 124                 "   jz    2f\n"
 125                 "1:"ALR"  %0,%3\n"
 126                 "  "SLR"  %1,%3\n"
 127                 "  "SLR"  %2,%3\n"
 128                 "   j     0b\n"
 129                 "2:"SLR"  %0,%0\n"
 130                 "3: \n"
 131                 EX_TABLE(0b,3b)
 132                 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
 133                 : "d" (reg0) : "cc", "memory");
 134         return size;
 135 }
 136
 137 size_t clear_user_mvcos(size_t size, void __user *to)
 138 {
 139         register unsigned long reg0 asm("0") = 0x810000UL;
 140         unsigned long tmp1, tmp2;
 141
 142         tmp1 = -4096UL;
 143         asm volatile(
 144                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
 145                 "   jz    4f\n"
 146                 "1:"ALR"  %0,%2\n"
 147                 "  "SLR"  %1,%2\n"
 148                 "   j     0b\n"
 149                 "2: la    %3,4095(%1)\n"/* %4 = to + 4095 */
 150                 "   nr    %3,%2\n"      /* %4 = (to + 4095) & -4096 */
 151                 "  "SLR"  %3,%1\n"
 152                 "  "CLR"  %0,%3\n"      /* copy crosses next page boundary? */
 153                 "   jnh   5f\n"
 154                 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
 155                 "  "SLR"  %0,%3\n"
 156                 "   j     5f\n"
 157                 "4:"SLR"  %0,%0\n"
 158                 "5: \n"
 159                 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
 160                 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
 161                 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
 162         return size;
 163 }
 164
 165 extern size_t strnlen_user_std(size_t, const char __user *);
 166 extern size_t strncpy_from_user_std(size_t, const char __user *, char *);
 167 extern int futex_atomic_op(int, int __user *, int, int *);
 168 extern int futex_atomic_cmpxchg(int __user *, int, int);
 169
 170 struct uaccess_ops uaccess_mvcos = {
 171         .copy_from_user = copy_from_user_mvcos_check,
 172         .copy_from_user_small = copy_from_user_std,
 173         .copy_to_user = copy_to_user_mvcos_check,
 174         .copy_to_user_small = copy_to_user_std,
 175         .copy_in_user = copy_in_user_mvcos,
 176         .clear_user = clear_user_mvcos,
 177         .strnlen_user = strnlen_user_std,
 178         .strncpy_from_user = strncpy_from_user_std,
 179         .futex_atomic_op = futex_atomic_op,
 180         .futex_atomic_cmpxchg = futex_atomic_cmpxchg,
 181 };