arch/s390/lib/uaccess.c

   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. 2006,2014
   6  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   7  *               Gerald Schaefer (gerald.schaefer@de.ibm.com)
   8  */
   9
  10 #include <linux/jump_label.h>
  11 #include <linux/uaccess.h>
  12 #include <linux/export.h>
  13 #include <linux/errno.h>
  14 #include <linux/mm.h>
  15 #include <asm/mmu_context.h>
  16 #include <asm/facility.h>
  17
  18 static DEFINE_STATIC_KEY_FALSE(have_mvcos);
  19
  20 static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
  21                                                  unsigned long size)
  22 {
  23         register unsigned long reg0 asm("0") = 0x81UL;
  24         unsigned long tmp1, tmp2;
  25
  26         tmp1 = -4096UL;
  27         asm volatile(
  28                 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
  29                 "6: jz    4f\n"
  30                 "1: algr  %0,%3\n"
  31                 "   slgr  %1,%3\n"
  32                 "   slgr  %2,%3\n"
  33                 "   j     0b\n"
  34                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
  35                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
  36                 "   slgr  %4,%1\n"
  37                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
  38                 "   jnh   5f\n"
  39                 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
  40                 "7: slgr  %0,%4\n"
  41                 "   j     5f\n"
  42                 "4: slgr  %0,%0\n"
  43                 "5:\n"
  44                 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
  45                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  46                 : "d" (reg0) : "cc", "memory");
  47         return size;
  48 }
  49
  50 static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
  51                                                 unsigned long size)
  52 {
  53         unsigned long tmp1, tmp2;
  54
  55         load_kernel_asce();
  56         tmp1 = -256UL;
  57         asm volatile(
  58                 "   sacf  0\n"
  59                 "0: mvcp  0(%0,%2),0(%1),%3\n"
  60                 "7: jz    5f\n"
  61                 "1: algr  %0,%3\n"
  62                 "   la    %1,256(%1)\n"
  63                 "   la    %2,256(%2)\n"
  64                 "2: mvcp  0(%0,%2),0(%1),%3\n"
  65                 "8: jnz   1b\n"
  66                 "   j     5f\n"
  67                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
  68                 "   lghi  %3,-4096\n"
  69                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
  70                 "   slgr  %4,%1\n"
  71                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
  72                 "   jnh   6f\n"
  73                 "4: mvcp  0(%4,%2),0(%1),%3\n"
  74                 "9: slgr  %0,%4\n"
  75                 "   j     6f\n"
  76                 "5: slgr  %0,%0\n"
  77                 "6: sacf  768\n"
  78                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
  79                 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
  80                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  81                 : : "cc", "memory");
  82         return size;
  83 }
  84
  85 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
  86 {
  87         if (static_branch_likely(&have_mvcos))
  88                 return copy_from_user_mvcos(to, from, n);
  89         return copy_from_user_mvcp(to, from, n);
  90 }
  91 EXPORT_SYMBOL(raw_copy_from_user);
  92
  93 static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
  94                                                unsigned long size)
  95 {
  96         register unsigned long reg0 asm("0") = 0x810000UL;
  97         unsigned long tmp1, tmp2;
  98
  99         tmp1 = -4096UL;
 100         asm volatile(
 101                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
 102                 "6: jz    4f\n"
 103                 "1: algr  %0,%3\n"
 104                 "   slgr  %1,%3\n"
 105                 "   slgr  %2,%3\n"
 106                 "   j     0b\n"
 107                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
 108                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
 109                 "   slgr  %4,%1\n"
 110                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
 111                 "   jnh   5f\n"
 112                 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
 113                 "7: slgr  %0,%4\n"
 114                 "   j     5f\n"
 115                 "4: slgr  %0,%0\n"
 116                 "5:\n"
 117                 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
 118                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 119                 : "d" (reg0) : "cc", "memory");
 120         return size;
 121 }
 122
 123 static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
 124                                               unsigned long size)
 125 {
 126         unsigned long tmp1, tmp2;
 127
 128         load_kernel_asce();
 129         tmp1 = -256UL;
 130         asm volatile(
 131                 "   sacf  0\n"
 132                 "0: mvcs  0(%0,%1),0(%2),%3\n"
 133                 "7: jz    5f\n"
 134                 "1: algr  %0,%3\n"
 135                 "   la    %1,256(%1)\n"
 136                 "   la    %2,256(%2)\n"
 137                 "2: mvcs  0(%0,%1),0(%2),%3\n"
 138                 "8: jnz   1b\n"
 139                 "   j     5f\n"
 140                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
 141                 "   lghi  %3,-4096\n"
 142                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
 143                 "   slgr  %4,%1\n"
 144                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
 145                 "   jnh   6f\n"
 146                 "4: mvcs  0(%4,%1),0(%2),%3\n"
 147                 "9: slgr  %0,%4\n"
 148                 "   j     6f\n"
 149                 "5: slgr  %0,%0\n"
 150                 "6: sacf  768\n"
 151                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
 152                 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
 153                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 154                 : : "cc", "memory");
 155         return size;
 156 }
 157
 158 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 159 {
 160         if (static_branch_likely(&have_mvcos))
 161                 return copy_to_user_mvcos(to, from, n);
 162         return copy_to_user_mvcs(to, from, n);
 163 }
 164 EXPORT_SYMBOL(raw_copy_to_user);
 165
 166 static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from,
 167                                                unsigned long size)
 168 {
 169         register unsigned long reg0 asm("0") = 0x810081UL;
 170         unsigned long tmp1, tmp2;
 171
 172         tmp1 = -4096UL;
 173         /* FIXME: copy with reduced length. */
 174         asm volatile(
 175                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
 176                 "   jz    2f\n"
 177                 "1: algr  %0,%3\n"
 178                 "   slgr  %1,%3\n"
 179                 "   slgr  %2,%3\n"
 180                 "   j     0b\n"
 181                 "2:slgr  %0,%0\n"
 182                 "3: \n"
 183                 EX_TABLE(0b,3b)
 184                 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
 185                 : "d" (reg0) : "cc", "memory");
 186         return size;
 187 }
 188
 189 static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from,
 190                                              unsigned long size)
 191 {
 192         unsigned long tmp1;
 193
 194         load_kernel_asce();
 195         asm volatile(
 196                 "   sacf  256\n"
 197                 "   aghi  %0,-1\n"
 198                 "   jo    5f\n"
 199                 "   bras  %3,3f\n"
 200                 "0: aghi  %0,257\n"
 201                 "1: mvc   0(1,%1),0(%2)\n"
 202                 "   la    %1,1(%1)\n"
 203                 "   la    %2,1(%2)\n"
 204                 "   aghi  %0,-1\n"
 205                 "   jnz   1b\n"
 206                 "   j     5f\n"
 207                 "2: mvc   0(256,%1),0(%2)\n"
 208                 "   la    %1,256(%1)\n"
 209                 "   la    %2,256(%2)\n"
 210                 "3: aghi  %0,-256\n"
 211                 "   jnm   2b\n"
 212                 "4: ex    %0,1b-0b(%3)\n"
 213                 "5: slgr  %0,%0\n"
 214                 "6: sacf  768\n"
 215                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 216                 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
 217                 : : "cc", "memory");
 218         return size;
 219 }
 220
 221 unsigned long raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 222 {
 223         if (static_branch_likely(&have_mvcos))
 224                 return copy_in_user_mvcos(to, from, n);
 225         return copy_in_user_mvc(to, from, n);
 226 }
 227 EXPORT_SYMBOL(raw_copy_in_user);
 228
 229 static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
 230 {
 231         register unsigned long reg0 asm("0") = 0x810000UL;
 232         unsigned long tmp1, tmp2;
 233
 234         tmp1 = -4096UL;
 235         asm volatile(
 236                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
 237                 "   jz    4f\n"
 238                 "1: algr  %0,%2\n"
 239                 "   slgr  %1,%2\n"
 240                 "   j     0b\n"
 241                 "2: la    %3,4095(%1)\n"/* %4 = to + 4095 */
 242                 "   nr    %3,%2\n"      /* %4 = (to + 4095) & -4096 */
 243                 "   slgr  %3,%1\n"
 244                 "   clgr  %0,%3\n"      /* copy crosses next page boundary? */
 245                 "   jnh   5f\n"
 246                 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
 247                 "   slgr  %0,%3\n"
 248                 "   j     5f\n"
 249                 "4: slgr  %0,%0\n"
 250                 "5:\n"
 251                 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
 252                 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
 253                 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
 254         return size;
 255 }
 256
 257 static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
 258 {
 259         unsigned long tmp1, tmp2;
 260
 261         load_kernel_asce();
 262         asm volatile(
 263                 "   sacf  256\n"
 264                 "   aghi  %0,-1\n"
 265                 "   jo    5f\n"
 266                 "   bras  %3,3f\n"
 267                 "   xc    0(1,%1),0(%1)\n"
 268                 "0: aghi  %0,257\n"
 269                 "   la    %2,255(%1)\n" /* %2 = ptr + 255 */
 270                 "   srl   %2,12\n"
 271                 "   sll   %2,12\n"      /* %2 = (ptr + 255) & -4096 */
 272                 "   slgr  %2,%1\n"
 273                 "   clgr  %0,%2\n"      /* clear crosses next page boundary? */
 274                 "   jnh   5f\n"
 275                 "   aghi  %2,-1\n"
 276                 "1: ex    %2,0(%3)\n"
 277                 "   aghi  %2,1\n"
 278                 "   slgr  %0,%2\n"
 279                 "   j     5f\n"
 280                 "2: xc    0(256,%1),0(%1)\n"
 281                 "   la    %1,256(%1)\n"
 282                 "3: aghi  %0,-256\n"
 283                 "   jnm   2b\n"
 284                 "4: ex    %0,0(%3)\n"
 285                 "5: slgr  %0,%0\n"
 286                 "6: sacf  768\n"
 287                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 288                 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
 289                 : : "cc", "memory");
 290         return size;
 291 }
 292
 293 unsigned long __clear_user(void __user *to, unsigned long size)
 294 {
 295         if (static_branch_likely(&have_mvcos))
 296                         return clear_user_mvcos(to, size);
 297         return clear_user_xc(to, size);
 298 }
 299 EXPORT_SYMBOL(__clear_user);
 300
 301 static inline unsigned long strnlen_user_srst(const char __user *src,
 302                                               unsigned long size)
 303 {
 304         register unsigned long reg0 asm("0") = 0;
 305         unsigned long tmp1, tmp2;
 306
 307         asm volatile(
 308                 "   la    %2,0(%1)\n"
 309                 "   la    %3,0(%0,%1)\n"
 310                 "   slgr  %0,%0\n"
 311                 "   sacf  256\n"
 312                 "0: srst  %3,%2\n"
 313                 "   jo    0b\n"
 314                 "   la    %0,1(%3)\n"   /* strnlen_user results includes \0 */
 315                 "   slgr  %0,%1\n"
 316                 "1: sacf  768\n"
 317                 EX_TABLE(0b,1b)
 318                 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
 319                 : "d" (reg0) : "cc", "memory");
 320         return size;
 321 }
 322
 323 unsigned long __strnlen_user(const char __user *src, unsigned long size)
 324 {
 325         if (unlikely(!size))
 326                 return 0;
 327         load_kernel_asce();
 328         return strnlen_user_srst(src, size);
 329 }
 330 EXPORT_SYMBOL(__strnlen_user);
 331
 332 long __strncpy_from_user(char *dst, const char __user *src, long size)
 333 {
 334         size_t done, len, offset, len_str;
 335
 336         if (unlikely(size <= 0))
 337                 return 0;
 338         done = 0;
 339         do {
 340                 offset = (size_t)src & (L1_CACHE_BYTES - 1);
 341                 len = min(size - done, L1_CACHE_BYTES - offset);
 342                 if (copy_from_user(dst, src, len))
 343                         return -EFAULT;
 344                 len_str = strnlen(dst, len);
 345                 done += len_str;
 346                 src += len_str;
 347                 dst += len_str;
 348         } while ((len_str == len) && (done < size));
 349         return done;
 350 }
 351 EXPORT_SYMBOL(__strncpy_from_user);
 352
 353 static int __init uaccess_init(void)
 354 {
 355         if (test_facility(27))
 356                 static_branch_enable(&have_mvcos);
 357         return 0;
 358 }
 359 early_initcall(uaccess_init);