arch/s390/include/asm/uaccess.h

   1 /*
   2  *  S390 version
   3  *    Copyright IBM Corp. 1999, 2000
   4  *    Author(s): Hartmut Penner (hp@de.ibm.com),
   5  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   6  *
   7  *  Derived from "include/asm-i386/uaccess.h"
   8  */
   9 #ifndef __S390_UACCESS_H
  10 #define __S390_UACCESS_H
  11
  12 /*
  13  * User space memory access functions
  14  */
  15 #include <linux/sched.h>
  16 #include <linux/errno.h>
  17 #include <asm/ctl_reg.h>
  18
  19 #define VERIFY_READ     0
  20 #define VERIFY_WRITE    1
  21
  22
  23 /*
  24  * The fs value determines whether argument validity checking should be
  25  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  26  * get_fs() == KERNEL_DS, checking is bypassed.
  27  *
  28  * For historical reasons, these macros are grossly misnamed.
  29  */
  30
  31 #define MAKE_MM_SEG(a)  ((mm_segment_t) { (a) })
  32
  33
  34 #define KERNEL_DS       MAKE_MM_SEG(0)
  35 #define USER_DS         MAKE_MM_SEG(1)
  36
  37 #define get_ds()        (KERNEL_DS)
  38 #define get_fs()        (current->thread.mm_segment)
  39
  40 #define set_fs(x) \
  41 ({                                                                      \
  42         unsigned long __pto;                                            \
  43         current->thread.mm_segment = (x);                               \
  44         __pto = current->thread.mm_segment.ar4 ?                        \
  45                 S390_lowcore.user_asce : S390_lowcore.kernel_asce;      \
  46         __ctl_load(__pto, 7, 7);                                        \
  47 })
  48
  49 #define segment_eq(a,b) ((a).ar4 == (b).ar4)
  50
  51 static inline int __range_ok(unsigned long addr, unsigned long size)
  52 {
  53         return 1;
  54 }
  55
  56 #define __access_ok(addr, size)                         \
  57 ({                                                      \
  58         __chk_user_ptr(addr);                           \
  59         __range_ok((unsigned long)(addr), (size));      \
  60 })
  61
  62 #define access_ok(type, addr, size) __access_ok(addr, size)
  63
  64 /*
  65  * The exception table consists of pairs of addresses: the first is the
  66  * address of an instruction that is allowed to fault, and the second is
  67  * the address at which the program should continue.  No registers are
  68  * modified, so it is entirely up to the continuation code to figure out
  69  * what to do.
  70  *
  71  * All the routines below use bits of fixup code that are out of line
  72  * with the main instruction path.  This means when everything is well,
  73  * we don't even have to jump over them.  Further, they do not intrude
  74  * on our cache or tlb entries.
  75  */
  76
  77 struct exception_table_entry
  78 {
  79         int insn, fixup;
  80 };
  81
  82 static inline unsigned long extable_fixup(const struct exception_table_entry *x)
  83 {
  84         return (unsigned long)&x->fixup + x->fixup;
  85 }
  86
  87 #define ARCH_HAS_RELATIVE_EXTABLE
  88
  89 /**
  90  * __copy_from_user: - Copy a block of data from user space, with less checking.
  91  * @to:   Destination address, in kernel space.
  92  * @from: Source address, in user space.
  93  * @n:    Number of bytes to copy.
  94  *
  95  * Context: User context only. This function may sleep if pagefaults are
  96  *          enabled.
  97  *
  98  * Copy data from user space to kernel space.  Caller must check
  99  * the specified block with access_ok() before calling this function.
 100  *
 101  * Returns number of bytes that could not be copied.
 102  * On success, this will be zero.
 103  *
 104  * If some data could not be copied, this function will pad the copied
 105  * data to the requested size using zero bytes.
 106  */
 107 unsigned long __must_check __copy_from_user(void *to, const void __user *from,
 108                                             unsigned long n);
 109
 110 /**
 111  * __copy_to_user: - Copy a block of data into user space, with less checking.
 112  * @to:   Destination address, in user space.
 113  * @from: Source address, in kernel space.
 114  * @n:    Number of bytes to copy.
 115  *
 116  * Context: User context only. This function may sleep if pagefaults are
 117  *          enabled.
 118  *
 119  * Copy data from kernel space to user space.  Caller must check
 120  * the specified block with access_ok() before calling this function.
 121  *
 122  * Returns number of bytes that could not be copied.
 123  * On success, this will be zero.
 124  */
 125 unsigned long __must_check __copy_to_user(void __user *to, const void *from,
 126                                           unsigned long n);
 127
 128 #define __copy_to_user_inatomic __copy_to_user
 129 #define __copy_from_user_inatomic __copy_from_user
 130
 131 #ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
 132
 133 #define __put_get_user_asm(to, from, size, spec)                \
 134 ({                                                              \
 135         register unsigned long __reg0 asm("0") = spec;          \
 136         int __rc;                                               \
 137                                                                 \
 138         asm volatile(                                           \
 139                 "0:     mvcos   %1,%3,%2\n"                     \
 140                 "1:     xr      %0,%0\n"                        \
 141                 "2:\n"                                          \
 142                 ".pushsection .fixup, \"ax\"\n"                 \
 143                 "3:     lhi     %0,%5\n"                        \
 144                 "       jg      2b\n"                           \
 145                 ".popsection\n"                                 \
 146                 EX_TABLE(0b,3b) EX_TABLE(1b,3b)                 \
 147                 : "=d" (__rc), "=Q" (*(to))                     \
 148                 : "d" (size), "Q" (*(from)),                    \
 149                   "d" (__reg0), "K" (-EFAULT)                   \
 150                 : "cc");                                        \
 151         __rc;                                                   \
 152 })
 153
 154 static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
 155 {
 156         unsigned long spec = 0x810000UL;
 157         int rc;
 158
 159         switch (size) {
 160         case 1:
 161                 rc = __put_get_user_asm((unsigned char __user *)ptr,
 162                                         (unsigned char *)x,
 163                                         size, spec);
 164                 break;
 165         case 2:
 166                 rc = __put_get_user_asm((unsigned short __user *)ptr,
 167                                         (unsigned short *)x,
 168                                         size, spec);
 169                 break;
 170         case 4:
 171                 rc = __put_get_user_asm((unsigned int __user *)ptr,
 172                                         (unsigned int *)x,
 173                                         size, spec);
 174                 break;
 175         case 8:
 176                 rc = __put_get_user_asm((unsigned long __user *)ptr,
 177                                         (unsigned long *)x,
 178                                         size, spec);
 179                 break;
 180         };
 181         return rc;
 182 }
 183
 184 static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
 185 {
 186         unsigned long spec = 0x81UL;
 187         int rc;
 188
 189         switch (size) {
 190         case 1:
 191                 rc = __put_get_user_asm((unsigned char *)x,
 192                                         (unsigned char __user *)ptr,
 193                                         size, spec);
 194                 break;
 195         case 2:
 196                 rc = __put_get_user_asm((unsigned short *)x,
 197                                         (unsigned short __user *)ptr,
 198                                         size, spec);
 199                 break;
 200         case 4:
 201                 rc = __put_get_user_asm((unsigned int *)x,
 202                                         (unsigned int __user *)ptr,
 203                                         size, spec);
 204                 break;
 205         case 8:
 206                 rc = __put_get_user_asm((unsigned long *)x,
 207                                         (unsigned long __user *)ptr,
 208                                         size, spec);
 209                 break;
 210         };
 211         return rc;
 212 }
 213
 214 #else /* CONFIG_HAVE_MARCH_Z10_FEATURES */
 215
 216 static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
 217 {
 218         size = __copy_to_user(ptr, x, size);
 219         return size ? -EFAULT : 0;
 220 }
 221
 222 static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
 223 {
 224         size = __copy_from_user(x, ptr, size);
 225         return size ? -EFAULT : 0;
 226 }
 227
 228 #endif /* CONFIG_HAVE_MARCH_Z10_FEATURES */
 229
 230 /*
 231  * These are the main single-value transfer routines.  They automatically
 232  * use the right size if we just have the right pointer type.
 233  */
 234 #define __put_user(x, ptr) \
 235 ({                                                              \
 236         __typeof__(*(ptr)) __x = (x);                           \
 237         int __pu_err = -EFAULT;                                 \
 238         __chk_user_ptr(ptr);                                    \
 239         switch (sizeof (*(ptr))) {                              \
 240         case 1:                                                 \
 241         case 2:                                                 \
 242         case 4:                                                 \
 243         case 8:                                                 \
 244                 __pu_err = __put_user_fn(&__x, ptr,             \
 245                                          sizeof(*(ptr)));       \
 246                 break;                                          \
 247         default:                                                \
 248                 __put_user_bad();                               \
 249                 break;                                          \
 250          }                                                      \
 251         __builtin_expect(__pu_err, 0);                          \
 252 })
 253
 254 #define put_user(x, ptr)                                        \
 255 ({                                                              \
 256         might_fault();                                          \
 257         __put_user(x, ptr);                                     \
 258 })
 259
 260
 261 int __put_user_bad(void) __attribute__((noreturn));
 262
 263 #define __get_user(x, ptr)                                      \
 264 ({                                                              \
 265         int __gu_err = -EFAULT;                                 \
 266         __chk_user_ptr(ptr);                                    \
 267         switch (sizeof(*(ptr))) {                               \
 268         case 1: {                                               \
 269                 unsigned char __x = 0;                          \
 270                 __gu_err = __get_user_fn(&__x, ptr,             \
 271                                          sizeof(*(ptr)));       \
 272                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 273                 break;                                          \
 274         };                                                      \
 275         case 2: {                                               \
 276                 unsigned short __x = 0;                         \
 277                 __gu_err = __get_user_fn(&__x, ptr,             \
 278                                          sizeof(*(ptr)));       \
 279                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 280                 break;                                          \
 281         };                                                      \
 282         case 4: {                                               \
 283                 unsigned int __x = 0;                           \
 284                 __gu_err = __get_user_fn(&__x, ptr,             \
 285                                          sizeof(*(ptr)));       \
 286                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 287                 break;                                          \
 288         };                                                      \
 289         case 8: {                                               \
 290                 unsigned long long __x = 0;                     \
 291                 __gu_err = __get_user_fn(&__x, ptr,             \
 292                                          sizeof(*(ptr)));       \
 293                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 294                 break;                                          \
 295         };                                                      \
 296         default:                                                \
 297                 __get_user_bad();                               \
 298                 break;                                          \
 299         }                                                       \
 300         __builtin_expect(__gu_err, 0);                          \
 301 })
 302
 303 #define get_user(x, ptr)                                        \
 304 ({                                                              \
 305         might_fault();                                          \
 306         __get_user(x, ptr);                                     \
 307 })
 308
 309 int __get_user_bad(void) __attribute__((noreturn));
 310
 311 #define __put_user_unaligned __put_user
 312 #define __get_user_unaligned __get_user
 313
 314 extern void __compiletime_error("usercopy buffer size is too small")
 315 __bad_copy_user(void);
 316
 317 static inline void copy_user_overflow(int size, unsigned long count)
 318 {
 319         WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
 320 }
 321
 322 /**
 323  * copy_to_user: - Copy a block of data into user space.
 324  * @to:   Destination address, in user space.
 325  * @from: Source address, in kernel space.
 326  * @n:    Number of bytes to copy.
 327  *
 328  * Context: User context only. This function may sleep if pagefaults are
 329  *          enabled.
 330  *
 331  * Copy data from kernel space to user space.
 332  *
 333  * Returns number of bytes that could not be copied.
 334  * On success, this will be zero.
 335  */
 336 static inline unsigned long __must_check
 337 copy_to_user(void __user *to, const void *from, unsigned long n)
 338 {
 339         might_fault();
 340         return __copy_to_user(to, from, n);
 341 }
 342
 343 /**
 344  * copy_from_user: - Copy a block of data from user space.
 345  * @to:   Destination address, in kernel space.
 346  * @from: Source address, in user space.
 347  * @n:    Number of bytes to copy.
 348  *
 349  * Context: User context only. This function may sleep if pagefaults are
 350  *          enabled.
 351  *
 352  * Copy data from user space to kernel space.
 353  *
 354  * Returns number of bytes that could not be copied.
 355  * On success, this will be zero.
 356  *
 357  * If some data could not be copied, this function will pad the copied
 358  * data to the requested size using zero bytes.
 359  */
 360 static inline unsigned long __must_check
 361 copy_from_user(void *to, const void __user *from, unsigned long n)
 362 {
 363         unsigned int sz = __compiletime_object_size(to);
 364
 365         might_fault();
 366         if (unlikely(sz != -1 && sz < n)) {
 367                 if (!__builtin_constant_p(n))
 368                         copy_user_overflow(sz, n);
 369                 else
 370                         __bad_copy_user();
 371                 return n;
 372         }
 373         return __copy_from_user(to, from, n);
 374 }
 375
 376 unsigned long __must_check
 377 __copy_in_user(void __user *to, const void __user *from, unsigned long n);
 378
 379 static inline unsigned long __must_check
 380 copy_in_user(void __user *to, const void __user *from, unsigned long n)
 381 {
 382         might_fault();
 383         return __copy_in_user(to, from, n);
 384 }
 385
 386 /*
 387  * Copy a null terminated string from userspace.
 388  */
 389
 390 long __strncpy_from_user(char *dst, const char __user *src, long count);
 391
 392 static inline long __must_check
 393 strncpy_from_user(char *dst, const char __user *src, long count)
 394 {
 395         might_fault();
 396         return __strncpy_from_user(dst, src, count);
 397 }
 398
 399 unsigned long __must_check __strnlen_user(const char __user *src, unsigned long count);
 400
 401 static inline unsigned long strnlen_user(const char __user *src, unsigned long n)
 402 {
 403         might_fault();
 404         return __strnlen_user(src, n);
 405 }
 406
 407 /**
 408  * strlen_user: - Get the size of a string in user space.
 409  * @str: The string to measure.
 410  *
 411  * Context: User context only. This function may sleep if pagefaults are
 412  *          enabled.
 413  *
 414  * Get the size of a NUL-terminated string in user space.
 415  *
 416  * Returns the size of the string INCLUDING the terminating NUL.
 417  * On exception, returns 0.
 418  *
 419  * If there is a limit on the length of a valid string, you may wish to
 420  * consider using strnlen_user() instead.
 421  */
 422 #define strlen_user(str) strnlen_user(str, ~0UL)
 423
 424 /*
 425  * Zero Userspace
 426  */
 427 unsigned long __must_check __clear_user(void __user *to, unsigned long size);
 428
 429 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
 430 {
 431         might_fault();
 432         return __clear_user(to, n);
 433 }
 434
 435 int copy_to_user_real(void __user *dest, void *src, unsigned long count);
 436 void s390_kernel_write(void *dst, const void *src, size_t size);
 437
 438 #endif /* __S390_UACCESS_H */