arch/s390/lib/uaccess_mvcos.c

   1 /*
   2  *  Optimized user space space access functions based on mvcos.
   3  *
   4  *    Copyright IBM Corp. 2006
   5  *    Author(s): Martin Schwidefsky ([email protected]),
   6  *               Gerald Schaefer ([email protected])
   7  */
   8
   9 #include <linux/errno.h>
  10 #include <linux/mm.h>
  11 #include <asm/uaccess.h>
  12 #include <asm/futex.h>
  13 #include "uaccess.h"
  14
  15 #ifndef CONFIG_64BIT
  16 #define AHI     "ahi"
  17 #define ALR     "alr"
  18 #define CLR     "clr"
  19 #define LHI     "lhi"
  20 #define SLR     "slr"
  21 #else
  22 #define AHI     "aghi"
  23 #define ALR     "algr"
  24 #define CLR     "clgr"
  25 #define LHI     "lghi"
  26 #define SLR     "slgr"
  27 #endif
  28
  29 static size_t copy_from_user_mvcos(size_t size, const void __user *ptr, void *x)
  30 {
  31         register unsigned long reg0 asm("0") = 0x81UL;
  32         unsigned long tmp1, tmp2;
  33
  34         tmp1 = -4096UL;
  35         asm volatile(
  36                 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
  37                 "9: jz    7f\n"
  38                 "1:"ALR"  %0,%3\n"
  39                 "  "SLR"  %1,%3\n"
  40                 "  "SLR"  %2,%3\n"
  41                 "   j     0b\n"
  42                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
  43                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
  44                 "  "SLR"  %4,%1\n"
  45                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
  46                 "   jnh   4f\n"
  47                 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
  48                 "10:"SLR"  %0,%4\n"
  49                 "  "ALR"  %2,%4\n"
  50                 "4:"LHI"  %4,-1\n"
  51                 "  "ALR"  %4,%0\n"      /* copy remaining size, subtract 1 */
  52                 "   bras  %3,6f\n"      /* memset loop */
  53                 "   xc    0(1,%2),0(%2)\n"
  54                 "5: xc    0(256,%2),0(%2)\n"
  55                 "   la    %2,256(%2)\n"
  56                 "6:"AHI"  %4,-256\n"
  57                 "   jnm   5b\n"
  58                 "   ex    %4,0(%3)\n"
  59                 "   j     8f\n"
  60                 "7:"SLR"  %0,%0\n"
  61                 "8: \n"
  62                 EX_TABLE(0b,2b) EX_TABLE(3b,4b) EX_TABLE(9b,2b) EX_TABLE(10b,4b)
  63                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  64                 : "d" (reg0) : "cc", "memory");
  65         return size;
  66 }
  67
  68 static size_t copy_to_user_mvcos(size_t size, void __user *ptr, const void *x)
  69 {
  70         register unsigned long reg0 asm("0") = 0x810000UL;
  71         unsigned long tmp1, tmp2;
  72
  73         tmp1 = -4096UL;
  74         asm volatile(
  75                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
  76                 "6: jz    4f\n"
  77                 "1:"ALR"  %0,%3\n"
  78                 "  "SLR"  %1,%3\n"
  79                 "  "SLR"  %2,%3\n"
  80                 "   j     0b\n"
  81                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
  82                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
  83                 "  "SLR"  %4,%1\n"
  84                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
  85                 "   jnh   5f\n"
  86                 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
  87                 "7:"SLR"  %0,%4\n"
  88                 "   j     5f\n"
  89                 "4:"SLR"  %0,%0\n"
  90                 "5: \n"
  91                 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
  92                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  93                 : "d" (reg0) : "cc", "memory");
  94         return size;
  95 }
  96
  97 static size_t copy_in_user_mvcos(size_t size, void __user *to,
  98                                  const void __user *from)
  99 {
 100         register unsigned long reg0 asm("0") = 0x810081UL;
 101         unsigned long tmp1, tmp2;
 102
 103         tmp1 = -4096UL;
 104         /* FIXME: copy with reduced length. */
 105         asm volatile(
 106                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
 107                 "   jz    2f\n"
 108                 "1:"ALR"  %0,%3\n"
 109                 "  "SLR"  %1,%3\n"
 110                 "  "SLR"  %2,%3\n"
 111                 "   j     0b\n"
 112                 "2:"SLR"  %0,%0\n"
 113                 "3: \n"
 114                 EX_TABLE(0b,3b)
 115                 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
 116                 : "d" (reg0) : "cc", "memory");
 117         return size;
 118 }
 119
 120 static size_t clear_user_mvcos(size_t size, void __user *to)
 121 {
 122         register unsigned long reg0 asm("0") = 0x810000UL;
 123         unsigned long tmp1, tmp2;
 124
 125         tmp1 = -4096UL;
 126         asm volatile(
 127                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
 128                 "   jz    4f\n"
 129                 "1:"ALR"  %0,%2\n"
 130                 "  "SLR"  %1,%2\n"
 131                 "   j     0b\n"
 132                 "2: la    %3,4095(%1)\n"/* %4 = to + 4095 */
 133                 "   nr    %3,%2\n"      /* %4 = (to + 4095) & -4096 */
 134                 "  "SLR"  %3,%1\n"
 135                 "  "CLR"  %0,%3\n"      /* copy crosses next page boundary? */
 136                 "   jnh   5f\n"
 137                 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
 138                 "  "SLR"  %0,%3\n"
 139                 "   j     5f\n"
 140                 "4:"SLR"  %0,%0\n"
 141                 "5: \n"
 142                 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
 143                 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
 144                 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
 145         return size;
 146 }
 147
 148 static size_t strnlen_user_mvcos(size_t count, const char __user *src)
 149 {
 150         size_t done, len, offset, len_str;
 151         char buf[256];
 152
 153         done = 0;
 154         do {
 155                 offset = (size_t)src & ~PAGE_MASK;
 156                 len = min(256UL, PAGE_SIZE - offset);
 157                 len = min(count - done, len);
 158                 if (copy_from_user_mvcos(len, src, buf))
 159                         return 0;
 160                 len_str = strnlen(buf, len);
 161                 done += len_str;
 162                 src += len_str;
 163         } while ((len_str == len) && (done < count));
 164         return done + 1;
 165 }
 166
 167 static size_t strncpy_from_user_mvcos(size_t count, const char __user *src,
 168                                       char *dst)
 169 {
 170         size_t done, len, offset, len_str;
 171
 172         if (unlikely(!count))
 173                 return 0;
 174         done = 0;
 175         do {
 176                 offset = (size_t)src & ~PAGE_MASK;
 177                 len = min(count - done, PAGE_SIZE - offset);
 178                 if (copy_from_user_mvcos(len, src, dst))
 179                         return -EFAULT;
 180                 len_str = strnlen(dst, len);
 181                 done += len_str;
 182                 src += len_str;
 183                 dst += len_str;
 184         } while ((len_str == len) && (done < count));
 185         return done;
 186 }
 187
 188 struct uaccess_ops uaccess_mvcos = {
 189         .copy_from_user = copy_from_user_mvcos,
 190         .copy_to_user = copy_to_user_mvcos,
 191         .copy_in_user = copy_in_user_mvcos,
 192         .clear_user = clear_user_mvcos,
 193         .strnlen_user = strnlen_user_mvcos,
 194         .strncpy_from_user = strncpy_from_user_mvcos,
 195         .futex_atomic_op = futex_atomic_op_pt,
 196         .futex_atomic_cmpxchg = futex_atomic_cmpxchg_pt,
 197 };