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 (schwidefsky@de.ibm.com),
   6  *               Gerald Schaefer (gerald.schaefer@de.ibm.com)
   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_from_user_mvcos_check(size_t size, const void __user *ptr, void *x)
  69 {
  70         if (size <= 256)
  71                 return copy_from_user_std(size, ptr, x);
  72         return copy_from_user_mvcos(size, ptr, x);
  73 }
  74
  75 static size_t copy_to_user_mvcos(size_t size, void __user *ptr, const void *x)
  76 {
  77         register unsigned long reg0 asm("0") = 0x810000UL;
  78         unsigned long tmp1, tmp2;
  79
  80         tmp1 = -4096UL;
  81         asm volatile(
  82                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
  83                 "6: jz    4f\n"
  84                 "1:"ALR"  %0,%3\n"
  85                 "  "SLR"  %1,%3\n"
  86                 "  "SLR"  %2,%3\n"
  87                 "   j     0b\n"
  88                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
  89                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
  90                 "  "SLR"  %4,%1\n"
  91                 "  "CLR"  %0,%4\n"      /* copy crosses next page boundary? */
  92                 "   jnh   5f\n"
  93                 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
  94                 "7:"SLR"  %0,%4\n"
  95                 "   j     5f\n"
  96                 "4:"SLR"  %0,%0\n"
  97                 "5: \n"
  98                 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
  99                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 100                 : "d" (reg0) : "cc", "memory");
 101         return size;
 102 }
 103
 104 static size_t copy_to_user_mvcos_check(size_t size, void __user *ptr,
 105                                        const void *x)
 106 {
 107         if (size <= 256)
 108                 return copy_to_user_std(size, ptr, x);
 109         return copy_to_user_mvcos(size, ptr, x);
 110 }
 111
 112 static size_t copy_in_user_mvcos(size_t size, void __user *to,
 113                                  const void __user *from)
 114 {
 115         register unsigned long reg0 asm("0") = 0x810081UL;
 116         unsigned long tmp1, tmp2;
 117
 118         tmp1 = -4096UL;
 119         /* FIXME: copy with reduced length. */
 120         asm volatile(
 121                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
 122                 "   jz    2f\n"
 123                 "1:"ALR"  %0,%3\n"
 124                 "  "SLR"  %1,%3\n"
 125                 "  "SLR"  %2,%3\n"
 126                 "   j     0b\n"
 127                 "2:"SLR"  %0,%0\n"
 128                 "3: \n"
 129                 EX_TABLE(0b,3b)
 130                 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
 131                 : "d" (reg0) : "cc", "memory");
 132         return size;
 133 }
 134
 135 static size_t clear_user_mvcos(size_t size, void __user *to)
 136 {
 137         register unsigned long reg0 asm("0") = 0x810000UL;
 138         unsigned long tmp1, tmp2;
 139
 140         tmp1 = -4096UL;
 141         asm volatile(
 142                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
 143                 "   jz    4f\n"
 144                 "1:"ALR"  %0,%2\n"
 145                 "  "SLR"  %1,%2\n"
 146                 "   j     0b\n"
 147                 "2: la    %3,4095(%1)\n"/* %4 = to + 4095 */
 148                 "   nr    %3,%2\n"      /* %4 = (to + 4095) & -4096 */
 149                 "  "SLR"  %3,%1\n"
 150                 "  "CLR"  %0,%3\n"      /* copy crosses next page boundary? */
 151                 "   jnh   5f\n"
 152                 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
 153                 "  "SLR"  %0,%3\n"
 154                 "   j     5f\n"
 155                 "4:"SLR"  %0,%0\n"
 156                 "5: \n"
 157                 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
 158                 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
 159                 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
 160         return size;
 161 }
 162
 163 static size_t strnlen_user_mvcos(size_t count, const char __user *src)
 164 {
 165         size_t done, len, offset, len_str;
 166         char buf[256];
 167
 168         done = 0;
 169         do {
 170                 offset = (size_t)src & ~PAGE_MASK;
 171                 len = min(256UL, PAGE_SIZE - offset);
 172                 len = min(count - done, len);
 173                 if (copy_from_user_mvcos(len, src, buf))
 174                         return 0;
 175                 len_str = strnlen(buf, len);
 176                 done += len_str;
 177                 src += len_str;
 178         } while ((len_str == len) && (done < count));
 179         return done + 1;
 180 }
 181
 182 static size_t strncpy_from_user_mvcos(size_t count, const char __user *src,
 183                                       char *dst)
 184 {
 185         size_t done, len, offset, len_str;
 186
 187         if (unlikely(!count))
 188                 return 0;
 189         done = 0;
 190         do {
 191                 offset = (size_t)src & ~PAGE_MASK;
 192                 len = min(count - done, PAGE_SIZE - offset);
 193                 if (copy_from_user_mvcos(len, src, dst))
 194                         return -EFAULT;
 195                 len_str = strnlen(dst, len);
 196                 done += len_str;
 197                 src += len_str;
 198                 dst += len_str;
 199         } while ((len_str == len) && (done < count));
 200         return done;
 201 }
 202
 203 struct uaccess_ops uaccess_mvcos = {
 204         .copy_from_user = copy_from_user_mvcos_check,
 205         .copy_from_user_small = copy_from_user_std,
 206         .copy_to_user = copy_to_user_mvcos_check,
 207         .copy_to_user_small = copy_to_user_std,
 208         .copy_in_user = copy_in_user_mvcos,
 209         .clear_user = clear_user_mvcos,
 210         .strnlen_user = strnlen_user_std,
 211         .strncpy_from_user = strncpy_from_user_std,
 212         .futex_atomic_op = futex_atomic_op_std,
 213         .futex_atomic_cmpxchg = futex_atomic_cmpxchg_std,
 214 };
 215
 216 struct uaccess_ops uaccess_mvcos_switch = {
 217         .copy_from_user = copy_from_user_mvcos,
 218         .copy_from_user_small = copy_from_user_mvcos,
 219         .copy_to_user = copy_to_user_mvcos,
 220         .copy_to_user_small = copy_to_user_mvcos,
 221         .copy_in_user = copy_in_user_mvcos,
 222         .clear_user = clear_user_mvcos,
 223         .strnlen_user = strnlen_user_mvcos,
 224         .strncpy_from_user = strncpy_from_user_mvcos,
 225         .futex_atomic_op = futex_atomic_op_pt,
 226         .futex_atomic_cmpxchg = futex_atomic_cmpxchg_pt,
 227 };