arch/s390/lib/uaccess.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Standard user space access functions based on mvcp/mvcs and doing
   4  *  interesting things in the secondary space mode.
   5  *
   6  *    Copyright IBM Corp. 2006,2014
   7  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   8  *               Gerald Schaefer (gerald.schaefer@de.ibm.com)
   9  */
  10
  11 #include <linux/jump_label.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/export.h>
  14 #include <linux/errno.h>
  15 #include <linux/mm.h>
  16 #include <asm/mmu_context.h>
  17 #include <asm/facility.h>
  18
  19 #ifdef CONFIG_DEBUG_USER_ASCE
  20 void debug_user_asce(void)
  21 {
  22         unsigned long cr1, cr7;
  23
  24         __ctl_store(cr1, 1, 1);
  25         __ctl_store(cr7, 7, 7);
  26         if (cr1 == S390_lowcore.kernel_asce && cr7 == S390_lowcore.user_asce)
  27                 return;
  28         panic("incorrect ASCE on kernel exit\n"
  29               "cr1:    %016lx cr7:  %016lx\n"
  30               "kernel: %016llx user: %016llx\n",
  31               cr1, cr7, S390_lowcore.kernel_asce, S390_lowcore.user_asce);
  32 }
  33 #endif /*CONFIG_DEBUG_USER_ASCE */
  34
  35 #ifndef CONFIG_HAVE_MARCH_Z10_FEATURES
  36 static DEFINE_STATIC_KEY_FALSE(have_mvcos);
  37
  38 static int __init uaccess_init(void)
  39 {
  40         if (test_facility(27))
  41                 static_branch_enable(&have_mvcos);
  42         return 0;
  43 }
  44 early_initcall(uaccess_init);
  45
  46 static inline int copy_with_mvcos(void)
  47 {
  48         if (static_branch_likely(&have_mvcos))
  49                 return 1;
  50         return 0;
  51 }
  52 #else
  53 static inline int copy_with_mvcos(void)
  54 {
  55         return 1;
  56 }
  57 #endif
  58
  59 static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
  60                                                  unsigned long size)
  61 {
  62         register unsigned long reg0 asm("0") = 0x81UL;
  63         unsigned long tmp1, tmp2;
  64
  65         tmp1 = -4096UL;
  66         asm volatile(
  67                 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
  68                 "6: jz    4f\n"
  69                 "1: algr  %0,%3\n"
  70                 "   slgr  %1,%3\n"
  71                 "   slgr  %2,%3\n"
  72                 "   j     0b\n"
  73                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
  74                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
  75                 "   slgr  %4,%1\n"
  76                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
  77                 "   jnh   5f\n"
  78                 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
  79                 "7: slgr  %0,%4\n"
  80                 "   j     5f\n"
  81                 "4: slgr  %0,%0\n"
  82                 "5:\n"
  83                 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
  84                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  85                 : "d" (reg0) : "cc", "memory");
  86         return size;
  87 }
  88
  89 static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
  90                                                 unsigned long size)
  91 {
  92         unsigned long tmp1, tmp2;
  93
  94         tmp1 = -256UL;
  95         asm volatile(
  96                 "   sacf  0\n"
  97                 "0: mvcp  0(%0,%2),0(%1),%3\n"
  98                 "7: jz    5f\n"
  99                 "1: algr  %0,%3\n"
 100                 "   la    %1,256(%1)\n"
 101                 "   la    %2,256(%2)\n"
 102                 "2: mvcp  0(%0,%2),0(%1),%3\n"
 103                 "8: jnz   1b\n"
 104                 "   j     5f\n"
 105                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
 106                 "   lghi  %3,-4096\n"
 107                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
 108                 "   slgr  %4,%1\n"
 109                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
 110                 "   jnh   6f\n"
 111                 "4: mvcp  0(%4,%2),0(%1),%3\n"
 112                 "9: slgr  %0,%4\n"
 113                 "   j     6f\n"
 114                 "5: slgr  %0,%0\n"
 115                 "6: sacf  768\n"
 116                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
 117                 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
 118                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 119                 : : "cc", "memory");
 120         return size;
 121 }
 122
 123 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 124 {
 125         if (copy_with_mvcos())
 126                 return copy_from_user_mvcos(to, from, n);
 127         return copy_from_user_mvcp(to, from, n);
 128 }
 129 EXPORT_SYMBOL(raw_copy_from_user);
 130
 131 static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
 132                                                unsigned long size)
 133 {
 134         register unsigned long reg0 asm("0") = 0x810000UL;
 135         unsigned long tmp1, tmp2;
 136
 137         tmp1 = -4096UL;
 138         asm volatile(
 139                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
 140                 "6: jz    4f\n"
 141                 "1: algr  %0,%3\n"
 142                 "   slgr  %1,%3\n"
 143                 "   slgr  %2,%3\n"
 144                 "   j     0b\n"
 145                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
 146                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
 147                 "   slgr  %4,%1\n"
 148                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
 149                 "   jnh   5f\n"
 150                 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
 151                 "7: slgr  %0,%4\n"
 152                 "   j     5f\n"
 153                 "4: slgr  %0,%0\n"
 154                 "5:\n"
 155                 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
 156                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 157                 : "d" (reg0) : "cc", "memory");
 158         return size;
 159 }
 160
 161 static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
 162                                               unsigned long size)
 163 {
 164         unsigned long tmp1, tmp2;
 165
 166         tmp1 = -256UL;
 167         asm volatile(
 168                 "   sacf  0\n"
 169                 "0: mvcs  0(%0,%1),0(%2),%3\n"
 170                 "7: jz    5f\n"
 171                 "1: algr  %0,%3\n"
 172                 "   la    %1,256(%1)\n"
 173                 "   la    %2,256(%2)\n"
 174                 "2: mvcs  0(%0,%1),0(%2),%3\n"
 175                 "8: jnz   1b\n"
 176                 "   j     5f\n"
 177                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
 178                 "   lghi  %3,-4096\n"
 179                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
 180                 "   slgr  %4,%1\n"
 181                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
 182                 "   jnh   6f\n"
 183                 "4: mvcs  0(%4,%1),0(%2),%3\n"
 184                 "9: slgr  %0,%4\n"
 185                 "   j     6f\n"
 186                 "5: slgr  %0,%0\n"
 187                 "6: sacf  768\n"
 188                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
 189                 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
 190                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 191                 : : "cc", "memory");
 192         return size;
 193 }
 194
 195 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 196 {
 197         if (copy_with_mvcos())
 198                 return copy_to_user_mvcos(to, from, n);
 199         return copy_to_user_mvcs(to, from, n);
 200 }
 201 EXPORT_SYMBOL(raw_copy_to_user);
 202
 203 static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from,
 204                                                unsigned long size)
 205 {
 206         register unsigned long reg0 asm("0") = 0x810081UL;
 207         unsigned long tmp1, tmp2;
 208
 209         tmp1 = -4096UL;
 210         /* FIXME: copy with reduced length. */
 211         asm volatile(
 212                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
 213                 "   jz    2f\n"
 214                 "1: algr  %0,%3\n"
 215                 "   slgr  %1,%3\n"
 216                 "   slgr  %2,%3\n"
 217                 "   j     0b\n"
 218                 "2:slgr  %0,%0\n"
 219                 "3: \n"
 220                 EX_TABLE(0b,3b)
 221                 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
 222                 : "d" (reg0) : "cc", "memory");
 223         return size;
 224 }
 225
 226 static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from,
 227                                              unsigned long size)
 228 {
 229         unsigned long tmp1;
 230
 231         asm volatile(
 232                 "   sacf  256\n"
 233                 "   aghi  %0,-1\n"
 234                 "   jo    5f\n"
 235                 "   bras  %3,3f\n"
 236                 "0: aghi  %0,257\n"
 237                 "1: mvc   0(1,%1),0(%2)\n"
 238                 "   la    %1,1(%1)\n"
 239                 "   la    %2,1(%2)\n"
 240                 "   aghi  %0,-1\n"
 241                 "   jnz   1b\n"
 242                 "   j     5f\n"
 243                 "2: mvc   0(256,%1),0(%2)\n"
 244                 "   la    %1,256(%1)\n"
 245                 "   la    %2,256(%2)\n"
 246                 "3: aghi  %0,-256\n"
 247                 "   jnm   2b\n"
 248                 "4: ex    %0,1b-0b(%3)\n"
 249                 "5: slgr  %0,%0\n"
 250                 "6: sacf  768\n"
 251                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 252                 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
 253                 : : "cc", "memory");
 254         return size;
 255 }
 256
 257 unsigned long raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 258 {
 259         if (copy_with_mvcos())
 260                 return copy_in_user_mvcos(to, from, n);
 261         return copy_in_user_mvc(to, from, n);
 262 }
 263 EXPORT_SYMBOL(raw_copy_in_user);
 264
 265 static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
 266 {
 267         register unsigned long reg0 asm("0") = 0x810000UL;
 268         unsigned long tmp1, tmp2;
 269
 270         tmp1 = -4096UL;
 271         asm volatile(
 272                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
 273                 "   jz    4f\n"
 274                 "1: algr  %0,%2\n"
 275                 "   slgr  %1,%2\n"
 276                 "   j     0b\n"
 277                 "2: la    %3,4095(%1)\n"/* %4 = to + 4095 */
 278                 "   nr    %3,%2\n"      /* %4 = (to + 4095) & -4096 */
 279                 "   slgr  %3,%1\n"
 280                 "   clgr  %0,%3\n"      /* copy crosses next page boundary? */
 281                 "   jnh   5f\n"
 282                 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
 283                 "   slgr  %0,%3\n"
 284                 "   j     5f\n"
 285                 "4: slgr  %0,%0\n"
 286                 "5:\n"
 287                 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
 288                 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
 289                 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
 290         return size;
 291 }
 292
 293 static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
 294 {
 295         unsigned long tmp1, tmp2;
 296
 297         asm volatile(
 298                 "   sacf  256\n"
 299                 "   aghi  %0,-1\n"
 300                 "   jo    5f\n"
 301                 "   bras  %3,3f\n"
 302                 "   xc    0(1,%1),0(%1)\n"
 303                 "0: aghi  %0,257\n"
 304                 "   la    %2,255(%1)\n" /* %2 = ptr + 255 */
 305                 "   srl   %2,12\n"
 306                 "   sll   %2,12\n"      /* %2 = (ptr + 255) & -4096 */
 307                 "   slgr  %2,%1\n"
 308                 "   clgr  %0,%2\n"      /* clear crosses next page boundary? */
 309                 "   jnh   5f\n"
 310                 "   aghi  %2,-1\n"
 311                 "1: ex    %2,0(%3)\n"
 312                 "   aghi  %2,1\n"
 313                 "   slgr  %0,%2\n"
 314                 "   j     5f\n"
 315                 "2: xc    0(256,%1),0(%1)\n"
 316                 "   la    %1,256(%1)\n"
 317                 "3: aghi  %0,-256\n"
 318                 "   jnm   2b\n"
 319                 "4: ex    %0,0(%3)\n"
 320                 "5: slgr  %0,%0\n"
 321                 "6: sacf  768\n"
 322                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 323                 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
 324                 : : "cc", "memory");
 325         return size;
 326 }
 327
 328 unsigned long __clear_user(void __user *to, unsigned long size)
 329 {
 330         if (copy_with_mvcos())
 331                         return clear_user_mvcos(to, size);
 332         return clear_user_xc(to, size);
 333 }
 334 EXPORT_SYMBOL(__clear_user);
 335
 336 static inline unsigned long strnlen_user_srst(const char __user *src,
 337                                               unsigned long size)
 338 {
 339         register unsigned long reg0 asm("0") = 0;
 340         unsigned long tmp1, tmp2;
 341
 342         asm volatile(
 343                 "   la    %2,0(%1)\n"
 344                 "   la    %3,0(%0,%1)\n"
 345                 "   slgr  %0,%0\n"
 346                 "   sacf  256\n"
 347                 "0: srst  %3,%2\n"
 348                 "   jo    0b\n"
 349                 "   la    %0,1(%3)\n"   /* strnlen_user results includes \0 */
 350                 "   slgr  %0,%1\n"
 351                 "1: sacf  768\n"
 352                 EX_TABLE(0b,1b)
 353                 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
 354                 : "d" (reg0) : "cc", "memory");
 355         return size;
 356 }
 357
 358 unsigned long __strnlen_user(const char __user *src, unsigned long size)
 359 {
 360         if (unlikely(!size))
 361                 return 0;
 362         return strnlen_user_srst(src, size);
 363 }
 364 EXPORT_SYMBOL(__strnlen_user);
 365
 366 long __strncpy_from_user(char *dst, const char __user *src, long size)
 367 {
 368         size_t done, len, offset, len_str;
 369
 370         if (unlikely(size <= 0))
 371                 return 0;
 372         done = 0;
 373         do {
 374                 offset = (size_t)src & (L1_CACHE_BYTES - 1);
 375                 len = min(size - done, L1_CACHE_BYTES - offset);
 376                 if (copy_from_user(dst, src, len))
 377                         return -EFAULT;
 378                 len_str = strnlen(dst, len);
 379                 done += len_str;
 380                 src += len_str;
 381                 dst += len_str;
 382         } while ((len_str == len) && (done < size));
 383         return done;
 384 }
 385 EXPORT_SYMBOL(__strncpy_from_user);