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_ENTRY
  20 void debug_user_asce(int exit)
  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 %s\n"
  29               "cr1:    %016lx cr7:  %016lx\n"
  30               "kernel: %016llx user: %016llx\n",
  31               exit ? "exit" : "entry", cr1, cr7,
  32               S390_lowcore.kernel_asce, S390_lowcore.user_asce);
  33
  34 }
  35 #endif /*CONFIG_DEBUG_ENTRY */
  36
  37 #ifndef CONFIG_HAVE_MARCH_Z10_FEATURES
  38 static DEFINE_STATIC_KEY_FALSE(have_mvcos);
  39
  40 static int __init uaccess_init(void)
  41 {
  42         if (test_facility(27))
  43                 static_branch_enable(&have_mvcos);
  44         return 0;
  45 }
  46 early_initcall(uaccess_init);
  47
  48 static inline int copy_with_mvcos(void)
  49 {
  50         if (static_branch_likely(&have_mvcos))
  51                 return 1;
  52         return 0;
  53 }
  54 #else
  55 static inline int copy_with_mvcos(void)
  56 {
  57         return 1;
  58 }
  59 #endif
  60
  61 static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
  62                                                  unsigned long size)
  63 {
  64         register unsigned long reg0 asm("0") = 0x81UL;
  65         unsigned long tmp1, tmp2;
  66
  67         tmp1 = -4096UL;
  68         asm volatile(
  69                 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
  70                 "6: jz    4f\n"
  71                 "1: algr  %0,%3\n"
  72                 "   slgr  %1,%3\n"
  73                 "   slgr  %2,%3\n"
  74                 "   j     0b\n"
  75                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
  76                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
  77                 "   slgr  %4,%1\n"
  78                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
  79                 "   jnh   5f\n"
  80                 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
  81                 "7: slgr  %0,%4\n"
  82                 "   j     5f\n"
  83                 "4: slgr  %0,%0\n"
  84                 "5:\n"
  85                 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
  86                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
  87                 : "d" (reg0) : "cc", "memory");
  88         return size;
  89 }
  90
  91 static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
  92                                                 unsigned long size)
  93 {
  94         unsigned long tmp1, tmp2;
  95
  96         tmp1 = -256UL;
  97         asm volatile(
  98                 "   sacf  0\n"
  99                 "0: mvcp  0(%0,%2),0(%1),%3\n"
 100                 "7: jz    5f\n"
 101                 "1: algr  %0,%3\n"
 102                 "   la    %1,256(%1)\n"
 103                 "   la    %2,256(%2)\n"
 104                 "2: mvcp  0(%0,%2),0(%1),%3\n"
 105                 "8: jnz   1b\n"
 106                 "   j     5f\n"
 107                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
 108                 "   lghi  %3,-4096\n"
 109                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
 110                 "   slgr  %4,%1\n"
 111                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
 112                 "   jnh   6f\n"
 113                 "4: mvcp  0(%4,%2),0(%1),%3\n"
 114                 "9: slgr  %0,%4\n"
 115                 "   j     6f\n"
 116                 "5: slgr  %0,%0\n"
 117                 "6: sacf  768\n"
 118                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
 119                 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
 120                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 121                 : : "cc", "memory");
 122         return size;
 123 }
 124
 125 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 126 {
 127         if (copy_with_mvcos())
 128                 return copy_from_user_mvcos(to, from, n);
 129         return copy_from_user_mvcp(to, from, n);
 130 }
 131 EXPORT_SYMBOL(raw_copy_from_user);
 132
 133 static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
 134                                                unsigned long size)
 135 {
 136         register unsigned long reg0 asm("0") = 0x810000UL;
 137         unsigned long tmp1, tmp2;
 138
 139         tmp1 = -4096UL;
 140         asm volatile(
 141                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
 142                 "6: jz    4f\n"
 143                 "1: algr  %0,%3\n"
 144                 "   slgr  %1,%3\n"
 145                 "   slgr  %2,%3\n"
 146                 "   j     0b\n"
 147                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
 148                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
 149                 "   slgr  %4,%1\n"
 150                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
 151                 "   jnh   5f\n"
 152                 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
 153                 "7: slgr  %0,%4\n"
 154                 "   j     5f\n"
 155                 "4: slgr  %0,%0\n"
 156                 "5:\n"
 157                 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
 158                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 159                 : "d" (reg0) : "cc", "memory");
 160         return size;
 161 }
 162
 163 static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
 164                                               unsigned long size)
 165 {
 166         unsigned long tmp1, tmp2;
 167
 168         tmp1 = -256UL;
 169         asm volatile(
 170                 "   sacf  0\n"
 171                 "0: mvcs  0(%0,%1),0(%2),%3\n"
 172                 "7: jz    5f\n"
 173                 "1: algr  %0,%3\n"
 174                 "   la    %1,256(%1)\n"
 175                 "   la    %2,256(%2)\n"
 176                 "2: mvcs  0(%0,%1),0(%2),%3\n"
 177                 "8: jnz   1b\n"
 178                 "   j     5f\n"
 179                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
 180                 "   lghi  %3,-4096\n"
 181                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
 182                 "   slgr  %4,%1\n"
 183                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
 184                 "   jnh   6f\n"
 185                 "4: mvcs  0(%4,%1),0(%2),%3\n"
 186                 "9: slgr  %0,%4\n"
 187                 "   j     6f\n"
 188                 "5: slgr  %0,%0\n"
 189                 "6: sacf  768\n"
 190                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
 191                 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
 192                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
 193                 : : "cc", "memory");
 194         return size;
 195 }
 196
 197 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 198 {
 199         if (copy_with_mvcos())
 200                 return copy_to_user_mvcos(to, from, n);
 201         return copy_to_user_mvcs(to, from, n);
 202 }
 203 EXPORT_SYMBOL(raw_copy_to_user);
 204
 205 static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from,
 206                                                unsigned long size)
 207 {
 208         register unsigned long reg0 asm("0") = 0x810081UL;
 209         unsigned long tmp1, tmp2;
 210
 211         tmp1 = -4096UL;
 212         /* FIXME: copy with reduced length. */
 213         asm volatile(
 214                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
 215                 "   jz    2f\n"
 216                 "1: algr  %0,%3\n"
 217                 "   slgr  %1,%3\n"
 218                 "   slgr  %2,%3\n"
 219                 "   j     0b\n"
 220                 "2:slgr  %0,%0\n"
 221                 "3: \n"
 222                 EX_TABLE(0b,3b)
 223                 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
 224                 : "d" (reg0) : "cc", "memory");
 225         return size;
 226 }
 227
 228 static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from,
 229                                              unsigned long size)
 230 {
 231         unsigned long tmp1;
 232
 233         asm volatile(
 234                 "   sacf  256\n"
 235                 "   aghi  %0,-1\n"
 236                 "   jo    5f\n"
 237                 "   bras  %3,3f\n"
 238                 "0: aghi  %0,257\n"
 239                 "1: mvc   0(1,%1),0(%2)\n"
 240                 "   la    %1,1(%1)\n"
 241                 "   la    %2,1(%2)\n"
 242                 "   aghi  %0,-1\n"
 243                 "   jnz   1b\n"
 244                 "   j     5f\n"
 245                 "2: mvc   0(256,%1),0(%2)\n"
 246                 "   la    %1,256(%1)\n"
 247                 "   la    %2,256(%2)\n"
 248                 "3: aghi  %0,-256\n"
 249                 "   jnm   2b\n"
 250                 "4: ex    %0,1b-0b(%3)\n"
 251                 "5: slgr  %0,%0\n"
 252                 "6: sacf  768\n"
 253                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 254                 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
 255                 : : "cc", "memory");
 256         return size;
 257 }
 258
 259 unsigned long raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 260 {
 261         if (copy_with_mvcos())
 262                 return copy_in_user_mvcos(to, from, n);
 263         return copy_in_user_mvc(to, from, n);
 264 }
 265 EXPORT_SYMBOL(raw_copy_in_user);
 266
 267 static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
 268 {
 269         register unsigned long reg0 asm("0") = 0x810000UL;
 270         unsigned long tmp1, tmp2;
 271
 272         tmp1 = -4096UL;
 273         asm volatile(
 274                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
 275                 "   jz    4f\n"
 276                 "1: algr  %0,%2\n"
 277                 "   slgr  %1,%2\n"
 278                 "   j     0b\n"
 279                 "2: la    %3,4095(%1)\n"/* %4 = to + 4095 */
 280                 "   nr    %3,%2\n"      /* %4 = (to + 4095) & -4096 */
 281                 "   slgr  %3,%1\n"
 282                 "   clgr  %0,%3\n"      /* copy crosses next page boundary? */
 283                 "   jnh   5f\n"
 284                 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
 285                 "   slgr  %0,%3\n"
 286                 "   j     5f\n"
 287                 "4: slgr  %0,%0\n"
 288                 "5:\n"
 289                 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
 290                 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
 291                 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
 292         return size;
 293 }
 294
 295 static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
 296 {
 297         unsigned long tmp1, tmp2;
 298
 299         asm volatile(
 300                 "   sacf  256\n"
 301                 "   aghi  %0,-1\n"
 302                 "   jo    5f\n"
 303                 "   bras  %3,3f\n"
 304                 "   xc    0(1,%1),0(%1)\n"
 305                 "0: aghi  %0,257\n"
 306                 "   la    %2,255(%1)\n" /* %2 = ptr + 255 */
 307                 "   srl   %2,12\n"
 308                 "   sll   %2,12\n"      /* %2 = (ptr + 255) & -4096 */
 309                 "   slgr  %2,%1\n"
 310                 "   clgr  %0,%2\n"      /* clear crosses next page boundary? */
 311                 "   jnh   5f\n"
 312                 "   aghi  %2,-1\n"
 313                 "1: ex    %2,0(%3)\n"
 314                 "   aghi  %2,1\n"
 315                 "   slgr  %0,%2\n"
 316                 "   j     5f\n"
 317                 "2: xc    0(256,%1),0(%1)\n"
 318                 "   la    %1,256(%1)\n"
 319                 "3: aghi  %0,-256\n"
 320                 "   jnm   2b\n"
 321                 "4: ex    %0,0(%3)\n"
 322                 "5: slgr  %0,%0\n"
 323                 "6: sacf  768\n"
 324                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
 325                 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
 326                 : : "cc", "memory");
 327         return size;
 328 }
 329
 330 unsigned long __clear_user(void __user *to, unsigned long size)
 331 {
 332         if (copy_with_mvcos())
 333                         return clear_user_mvcos(to, size);
 334         return clear_user_xc(to, size);
 335 }
 336 EXPORT_SYMBOL(__clear_user);
 337
 338 static inline unsigned long strnlen_user_srst(const char __user *src,
 339                                               unsigned long size)
 340 {
 341         register unsigned long reg0 asm("0") = 0;
 342         unsigned long tmp1, tmp2;
 343
 344         asm volatile(
 345                 "   la    %2,0(%1)\n"
 346                 "   la    %3,0(%0,%1)\n"
 347                 "   slgr  %0,%0\n"
 348                 "   sacf  256\n"
 349                 "0: srst  %3,%2\n"
 350                 "   jo    0b\n"
 351                 "   la    %0,1(%3)\n"   /* strnlen_user results includes \0 */
 352                 "   slgr  %0,%1\n"
 353                 "1: sacf  768\n"
 354                 EX_TABLE(0b,1b)
 355                 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
 356                 : "d" (reg0) : "cc", "memory");
 357         return size;
 358 }
 359
 360 unsigned long __strnlen_user(const char __user *src, unsigned long size)
 361 {
 362         if (unlikely(!size))
 363                 return 0;
 364         return strnlen_user_srst(src, size);
 365 }
 366 EXPORT_SYMBOL(__strnlen_user);
 367
 368 long __strncpy_from_user(char *dst, const char __user *src, long size)
 369 {
 370         size_t done, len, offset, len_str;
 371
 372         if (unlikely(size <= 0))
 373                 return 0;
 374         done = 0;
 375         do {
 376                 offset = (size_t)src & (L1_CACHE_BYTES - 1);
 377                 len = min(size - done, L1_CACHE_BYTES - offset);
 378                 if (copy_from_user(dst, src, len))
 379                         return -EFAULT;
 380                 len_str = strnlen(dst, len);
 381                 done += len_str;
 382                 src += len_str;
 383                 dst += len_str;
 384         } while ((len_str == len) && (done < size));
 385         return done;
 386 }
 387 EXPORT_SYMBOL(__strncpy_from_user);