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_insn(const struct exception_table_entry *x)
  83 {
  84         return (unsigned long)&x->insn + x->insn;
  85 }
  86
  87 static inline unsigned long extable_fixup(const struct exception_table_entry *x)
  88 {
  89         return (unsigned long)&x->fixup + x->fixup;
  90 }
  91
  92 #define ARCH_HAS_SORT_EXTABLE
  93 #define ARCH_HAS_SEARCH_EXTABLE
  94
  95 struct uaccess_ops {
  96         size_t (*copy_from_user)(size_t, const void __user *, void *);
  97         size_t (*copy_to_user)(size_t, void __user *, const void *);
  98         size_t (*copy_in_user)(size_t, void __user *, const void __user *);
  99         size_t (*clear_user)(size_t, void __user *);
 100         size_t (*strnlen_user)(size_t, const char __user *);
 101         size_t (*strncpy_from_user)(size_t, const char __user *, char *);
 102         int (*futex_atomic_op)(int op, u32 __user *, int oparg, int *old);
 103         int (*futex_atomic_cmpxchg)(u32 *, u32 __user *, u32 old, u32 new);
 104 };
 105
 106 extern struct uaccess_ops uaccess;
 107 extern struct uaccess_ops uaccess_mvcos;
 108 extern struct uaccess_ops uaccess_pt;
 109
 110 extern int __handle_fault(unsigned long, unsigned long, int);
 111
 112 static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
 113 {
 114         size = uaccess.copy_to_user(size, ptr, x);
 115         return size ? -EFAULT : size;
 116 }
 117
 118 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
 119 {
 120         size = uaccess.copy_from_user(size, ptr, x);
 121         return size ? -EFAULT : size;
 122 }
 123
 124 /*
 125  * These are the main single-value transfer routines.  They automatically
 126  * use the right size if we just have the right pointer type.
 127  */
 128 #define __put_user(x, ptr) \
 129 ({                                                              \
 130         __typeof__(*(ptr)) __x = (x);                           \
 131         int __pu_err = -EFAULT;                                 \
 132         __chk_user_ptr(ptr);                                    \
 133         switch (sizeof (*(ptr))) {                              \
 134         case 1:                                                 \
 135         case 2:                                                 \
 136         case 4:                                                 \
 137         case 8:                                                 \
 138                 __pu_err = __put_user_fn(sizeof (*(ptr)),       \
 139                                          ptr, &__x);            \
 140                 break;                                          \
 141         default:                                                \
 142                 __put_user_bad();                               \
 143                 break;                                          \
 144          }                                                      \
 145         __pu_err;                                               \
 146 })
 147
 148 #define put_user(x, ptr)                                        \
 149 ({                                                              \
 150         might_fault();                                          \
 151         __put_user(x, ptr);                                     \
 152 })
 153
 154
 155 extern int __put_user_bad(void) __attribute__((noreturn));
 156
 157 #define __get_user(x, ptr)                                      \
 158 ({                                                              \
 159         int __gu_err = -EFAULT;                                 \
 160         __chk_user_ptr(ptr);                                    \
 161         switch (sizeof(*(ptr))) {                               \
 162         case 1: {                                               \
 163                 unsigned char __x;                              \
 164                 __gu_err = __get_user_fn(sizeof (*(ptr)),       \
 165                                          ptr, &__x);            \
 166                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 167                 break;                                          \
 168         };                                                      \
 169         case 2: {                                               \
 170                 unsigned short __x;                             \
 171                 __gu_err = __get_user_fn(sizeof (*(ptr)),       \
 172                                          ptr, &__x);            \
 173                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 174                 break;                                          \
 175         };                                                      \
 176         case 4: {                                               \
 177                 unsigned int __x;                               \
 178                 __gu_err = __get_user_fn(sizeof (*(ptr)),       \
 179                                          ptr, &__x);            \
 180                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 181                 break;                                          \
 182         };                                                      \
 183         case 8: {                                               \
 184                 unsigned long long __x;                         \
 185                 __gu_err = __get_user_fn(sizeof (*(ptr)),       \
 186                                          ptr, &__x);            \
 187                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 188                 break;                                          \
 189         };                                                      \
 190         default:                                                \
 191                 __get_user_bad();                               \
 192                 break;                                          \
 193         }                                                       \
 194         __gu_err;                                               \
 195 })
 196
 197 #define get_user(x, ptr)                                        \
 198 ({                                                              \
 199         might_fault();                                          \
 200         __get_user(x, ptr);                                     \
 201 })
 202
 203 extern int __get_user_bad(void) __attribute__((noreturn));
 204
 205 #define __put_user_unaligned __put_user
 206 #define __get_user_unaligned __get_user
 207
 208 /**
 209  * __copy_to_user: - Copy a block of data into user space, with less checking.
 210  * @to:   Destination address, in user space.
 211  * @from: Source address, in kernel space.
 212  * @n:    Number of bytes to copy.
 213  *
 214  * Context: User context only.  This function may sleep.
 215  *
 216  * Copy data from kernel space to user space.  Caller must check
 217  * the specified block with access_ok() before calling this function.
 218  *
 219  * Returns number of bytes that could not be copied.
 220  * On success, this will be zero.
 221  */
 222 static inline unsigned long __must_check
 223 __copy_to_user(void __user *to, const void *from, unsigned long n)
 224 {
 225         return uaccess.copy_to_user(n, to, from);
 226 }
 227
 228 #define __copy_to_user_inatomic __copy_to_user
 229 #define __copy_from_user_inatomic __copy_from_user
 230
 231 /**
 232  * copy_to_user: - Copy a block of data into user space.
 233  * @to:   Destination address, in user space.
 234  * @from: Source address, in kernel space.
 235  * @n:    Number of bytes to copy.
 236  *
 237  * Context: User context only.  This function may sleep.
 238  *
 239  * Copy data from kernel space to user space.
 240  *
 241  * Returns number of bytes that could not be copied.
 242  * On success, this will be zero.
 243  */
 244 static inline unsigned long __must_check
 245 copy_to_user(void __user *to, const void *from, unsigned long n)
 246 {
 247         might_fault();
 248         return __copy_to_user(to, from, n);
 249 }
 250
 251 /**
 252  * __copy_from_user: - Copy a block of data from user space, with less checking.
 253  * @to:   Destination address, in kernel space.
 254  * @from: Source address, in user space.
 255  * @n:    Number of bytes to copy.
 256  *
 257  * Context: User context only.  This function may sleep.
 258  *
 259  * Copy data from user space to kernel space.  Caller must check
 260  * the specified block with access_ok() before calling this function.
 261  *
 262  * Returns number of bytes that could not be copied.
 263  * On success, this will be zero.
 264  *
 265  * If some data could not be copied, this function will pad the copied
 266  * data to the requested size using zero bytes.
 267  */
 268 static inline unsigned long __must_check
 269 __copy_from_user(void *to, const void __user *from, unsigned long n)
 270 {
 271         return uaccess.copy_from_user(n, from, to);
 272 }
 273
 274 extern void copy_from_user_overflow(void)
 275 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
 276 __compiletime_warning("copy_from_user() buffer size is not provably correct")
 277 #endif
 278 ;
 279
 280 /**
 281  * copy_from_user: - Copy a block of data from user space.
 282  * @to:   Destination address, in kernel space.
 283  * @from: Source address, in user space.
 284  * @n:    Number of bytes to copy.
 285  *
 286  * Context: User context only.  This function may sleep.
 287  *
 288  * Copy data from user space to kernel space.
 289  *
 290  * Returns number of bytes that could not be copied.
 291  * On success, this will be zero.
 292  *
 293  * If some data could not be copied, this function will pad the copied
 294  * data to the requested size using zero bytes.
 295  */
 296 static inline unsigned long __must_check
 297 copy_from_user(void *to, const void __user *from, unsigned long n)
 298 {
 299         unsigned int sz = __compiletime_object_size(to);
 300
 301         might_fault();
 302         if (unlikely(sz != -1 && sz < n)) {
 303                 copy_from_user_overflow();
 304                 return n;
 305         }
 306         return __copy_from_user(to, from, n);
 307 }
 308
 309 static inline unsigned long __must_check
 310 __copy_in_user(void __user *to, const void __user *from, unsigned long n)
 311 {
 312         return uaccess.copy_in_user(n, to, from);
 313 }
 314
 315 static inline unsigned long __must_check
 316 copy_in_user(void __user *to, const void __user *from, unsigned long n)
 317 {
 318         might_fault();
 319         return __copy_in_user(to, from, n);
 320 }
 321
 322 /*
 323  * Copy a null terminated string from userspace.
 324  */
 325 static inline long __must_check
 326 strncpy_from_user(char *dst, const char __user *src, long count)
 327 {
 328         might_fault();
 329         return uaccess.strncpy_from_user(count, src, dst);
 330 }
 331
 332 static inline unsigned long
 333 strnlen_user(const char __user * src, unsigned long n)
 334 {
 335         might_fault();
 336         return uaccess.strnlen_user(n, src);
 337 }
 338
 339 /**
 340  * strlen_user: - Get the size of a string in user space.
 341  * @str: The string to measure.
 342  *
 343  * Context: User context only.  This function may sleep.
 344  *
 345  * Get the size of a NUL-terminated string in user space.
 346  *
 347  * Returns the size of the string INCLUDING the terminating NUL.
 348  * On exception, returns 0.
 349  *
 350  * If there is a limit on the length of a valid string, you may wish to
 351  * consider using strnlen_user() instead.
 352  */
 353 #define strlen_user(str) strnlen_user(str, ~0UL)
 354
 355 /*
 356  * Zero Userspace
 357  */
 358
 359 static inline unsigned long __must_check
 360 __clear_user(void __user *to, unsigned long n)
 361 {
 362         return uaccess.clear_user(n, to);
 363 }
 364
 365 static inline unsigned long __must_check
 366 clear_user(void __user *to, unsigned long n)
 367 {
 368         might_fault();
 369         return uaccess.clear_user(n, to);
 370 }
 371
 372 extern int copy_to_user_real(void __user *dest, void *src, size_t count);
 373 extern int copy_from_user_real(void *dest, void __user *src, size_t count);
 374
 375 #endif /* __S390_UACCESS_H */