include/asm-s390/uaccess.h

   1 /*
   2  *  include/asm-s390/uaccess.h
   3  *
   4  *  S390 version
   5  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Hartmut Penner (hp@de.ibm.com),
   7  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   8  *
   9  *  Derived from "include/asm-i386/uaccess.h"
  10  */
  11 #ifndef __S390_UACCESS_H
  12 #define __S390_UACCESS_H
  13
  14 /*
  15  * User space memory access functions
  16  */
  17 #include <linux/sched.h>
  18 #include <linux/errno.h>
  19
  20 #define VERIFY_READ     0
  21 #define VERIFY_WRITE    1
  22
  23
  24 /*
  25  * The fs value determines whether argument validity checking should be
  26  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  27  * get_fs() == KERNEL_DS, checking is bypassed.
  28  *
  29  * For historical reasons, these macros are grossly misnamed.
  30  */
  31
  32 #define MAKE_MM_SEG(a)  ((mm_segment_t) { (a) })
  33
  34
  35 #define KERNEL_DS       MAKE_MM_SEG(0)
  36 #define USER_DS         MAKE_MM_SEG(1)
  37
  38 #define get_ds()        (KERNEL_DS)
  39 #define get_fs()        (current->thread.mm_segment)
  40
  41 #ifdef __s390x__
  42 #define set_fs(x) \
  43 ({                                                                      \
  44         unsigned long __pto;                                            \
  45         current->thread.mm_segment = (x);                               \
  46         __pto = current->thread.mm_segment.ar4 ?                        \
  47                 S390_lowcore.user_asce : S390_lowcore.kernel_asce;      \
  48         asm volatile ("lctlg 7,7,%0" : : "m" (__pto) );                 \
  49 })
  50 #else
  51 #define set_fs(x) \
  52 ({                                                                      \
  53         unsigned long __pto;                                            \
  54         current->thread.mm_segment = (x);                               \
  55         __pto = current->thread.mm_segment.ar4 ?                        \
  56                 S390_lowcore.user_asce : S390_lowcore.kernel_asce;      \
  57         asm volatile ("lctl  7,7,%0" : : "m" (__pto) );                 \
  58 })
  59 #endif
  60
  61 #define segment_eq(a,b) ((a).ar4 == (b).ar4)
  62
  63
  64 #define __access_ok(addr,size) (1)
  65
  66 #define access_ok(type,addr,size) __access_ok(addr,size)
  67
  68 /* this function will go away soon - use access_ok() instead */
  69 extern inline int __deprecated verify_area(int type, const void __user *addr,
  70                                                 unsigned long size)
  71 {
  72         return access_ok(type, addr, size) ? 0 : -EFAULT;
  73 }
  74
  75 /*
  76  * The exception table consists of pairs of addresses: the first is the
  77  * address of an instruction that is allowed to fault, and the second is
  78  * the address at which the program should continue.  No registers are
  79  * modified, so it is entirely up to the continuation code to figure out
  80  * what to do.
  81  *
  82  * All the routines below use bits of fixup code that are out of line
  83  * with the main instruction path.  This means when everything is well,
  84  * we don't even have to jump over them.  Further, they do not intrude
  85  * on our cache or tlb entries.
  86  */
  87
  88 struct exception_table_entry
  89 {
  90         unsigned long insn, fixup;
  91 };
  92
  93 #ifndef __s390x__
  94 #define __uaccess_fixup \
  95         ".section .fixup,\"ax\"\n"      \
  96         "2: lhi    %0,%4\n"             \
  97         "   bras   1,3f\n"              \
  98         "   .long  1b\n"                \
  99         "3: l      1,0(1)\n"            \
 100         "   br     1\n"                 \
 101         ".previous\n"                   \
 102         ".section __ex_table,\"a\"\n"   \
 103         "   .align 4\n"                 \
 104         "   .long  0b,2b\n"             \
 105         ".previous"
 106 #define __uaccess_clobber "cc", "1"
 107 #else /* __s390x__ */
 108 #define __uaccess_fixup \
 109         ".section .fixup,\"ax\"\n"      \
 110         "2: lghi   %0,%4\n"             \
 111         "   jg     1b\n"                \
 112         ".previous\n"                   \
 113         ".section __ex_table,\"a\"\n"   \
 114         "   .align 8\n"                 \
 115         "   .quad  0b,2b\n"             \
 116         ".previous"
 117 #define __uaccess_clobber "cc"
 118 #endif /* __s390x__ */
 119
 120 /*
 121  * These are the main single-value transfer routines.  They automatically
 122  * use the right size if we just have the right pointer type.
 123  */
 124 #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
 125 #define __put_user_asm(x, ptr, err) \
 126 ({                                                              \
 127         err = 0;                                                \
 128         asm volatile(                                           \
 129                 "0: mvcs  0(%1,%2),%3,%0\n"                     \
 130                 "1:\n"                                          \
 131                 __uaccess_fixup                                 \
 132                 : "+&d" (err)                                   \
 133                 : "d" (sizeof(*(ptr))), "a" (ptr), "Q" (x),     \
 134                   "K" (-EFAULT)                                 \
 135                 : __uaccess_clobber );                          \
 136 })
 137 #else
 138 #define __put_user_asm(x, ptr, err) \
 139 ({                                                              \
 140         err = 0;                                                \
 141         asm volatile(                                           \
 142                 "0: mvcs  0(%1,%2),0(%3),%0\n"                  \
 143                 "1:\n"                                          \
 144                 __uaccess_fixup                                 \
 145                 : "+&d" (err)                                   \
 146                 : "d" (sizeof(*(ptr))), "a" (ptr), "a" (&(x)),  \
 147                   "K" (-EFAULT), "m" (x)                        \
 148                 : __uaccess_clobber );                          \
 149 })
 150 #endif
 151
 152 #ifndef __CHECKER__
 153 #define __put_user(x, ptr) \
 154 ({                                                              \
 155         __typeof__(*(ptr)) __x = (x);                           \
 156         int __pu_err;                                           \
 157         switch (sizeof (*(ptr))) {                              \
 158         case 1:                                                 \
 159         case 2:                                                 \
 160         case 4:                                                 \
 161         case 8:                                                 \
 162                 __put_user_asm(__x, ptr, __pu_err);             \
 163                 break;                                          \
 164         default:                                                \
 165                 __put_user_bad();                               \
 166                 break;                                          \
 167          }                                                      \
 168         __pu_err;                                               \
 169 })
 170 #else
 171 #define __put_user(x, ptr)                      \
 172 ({                                              \
 173         void __user *p;                         \
 174         p = (ptr);                              \
 175         0;                                      \
 176 })
 177 #endif
 178
 179 #define put_user(x, ptr)                                        \
 180 ({                                                              \
 181         might_sleep();                                          \
 182         __put_user(x, ptr);                                     \
 183 })
 184
 185
 186 extern int __put_user_bad(void) __attribute__((noreturn));
 187
 188 #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
 189 #define __get_user_asm(x, ptr, err) \
 190 ({                                                              \
 191         err = 0;                                                \
 192         asm volatile (                                          \
 193                 "0: mvcp  %O1(%2,%R1),0(%3),%0\n"               \
 194                 "1:\n"                                          \
 195                 __uaccess_fixup                                 \
 196                 : "+&d" (err), "=Q" (x)                         \
 197                 : "d" (sizeof(*(ptr))), "a" (ptr),              \
 198                   "K" (-EFAULT)                                 \
 199                 : __uaccess_clobber );                          \
 200 })
 201 #else
 202 #define __get_user_asm(x, ptr, err) \
 203 ({                                                              \
 204         err = 0;                                                \
 205         asm volatile (                                          \
 206                 "0: mvcp  0(%2,%5),0(%3),%0\n"                  \
 207                 "1:\n"                                          \
 208                 __uaccess_fixup                                 \
 209                 : "+&d" (err), "=m" (x)                         \
 210                 : "d" (sizeof(*(ptr))), "a" (ptr),              \
 211                   "K" (-EFAULT), "a" (&(x))                     \
 212                 : __uaccess_clobber );                          \
 213 })
 214 #endif
 215
 216 #ifndef __CHECKER__
 217 #define __get_user(x, ptr)                                      \
 218 ({                                                              \
 219         __typeof__(*(ptr)) __x;                                 \
 220         int __gu_err;                                           \
 221         switch (sizeof(*(ptr))) {                               \
 222         case 1:                                                 \
 223         case 2:                                                 \
 224         case 4:                                                 \
 225         case 8:                                                 \
 226                 __get_user_asm(__x, ptr, __gu_err);             \
 227                 break;                                          \
 228         default:                                                \
 229                 __get_user_bad();                               \
 230                 break;                                          \
 231         }                                                       \
 232         (x) = __x;                                              \
 233         __gu_err;                                               \
 234 })
 235 #else
 236 #define __get_user(x, ptr)                      \
 237 ({                                              \
 238         void __user *p;                         \
 239         p = (ptr);                              \
 240         0;                                      \
 241 })
 242 #endif
 243
 244
 245 #define get_user(x, ptr)                                        \
 246 ({                                                              \
 247         might_sleep();                                          \
 248         __get_user(x, ptr);                                     \
 249 })
 250
 251 extern int __get_user_bad(void) __attribute__((noreturn));
 252
 253 #define __put_user_unaligned __put_user
 254 #define __get_user_unaligned __get_user
 255
 256 extern long __copy_to_user_asm(const void *from, long n, void __user *to);
 257
 258 /**
 259  * __copy_to_user: - Copy a block of data into user space, with less checking.
 260  * @to:   Destination address, in user space.
 261  * @from: Source address, in kernel space.
 262  * @n:    Number of bytes to copy.
 263  *
 264  * Context: User context only.  This function may sleep.
 265  *
 266  * Copy data from kernel space to user space.  Caller must check
 267  * the specified block with access_ok() before calling this function.
 268  *
 269  * Returns number of bytes that could not be copied.
 270  * On success, this will be zero.
 271  */
 272 static inline unsigned long
 273 __copy_to_user(void __user *to, const void *from, unsigned long n)
 274 {
 275         return __copy_to_user_asm(from, n, to);
 276 }
 277
 278 #define __copy_to_user_inatomic __copy_to_user
 279 #define __copy_from_user_inatomic __copy_from_user
 280
 281 /**
 282  * copy_to_user: - Copy a block of data into user space.
 283  * @to:   Destination address, in user space.
 284  * @from: Source address, in kernel space.
 285  * @n:    Number of bytes to copy.
 286  *
 287  * Context: User context only.  This function may sleep.
 288  *
 289  * Copy data from kernel space to user space.
 290  *
 291  * Returns number of bytes that could not be copied.
 292  * On success, this will be zero.
 293  */
 294 static inline unsigned long
 295 copy_to_user(void __user *to, const void *from, unsigned long n)
 296 {
 297         might_sleep();
 298         if (access_ok(VERIFY_WRITE, to, n))
 299                 n = __copy_to_user(to, from, n);
 300         return n;
 301 }
 302
 303 extern long __copy_from_user_asm(void *to, long n, const void __user *from);
 304
 305 /**
 306  * __copy_from_user: - Copy a block of data from user space, with less checking.
 307  * @to:   Destination address, in kernel space.
 308  * @from: Source address, in user space.
 309  * @n:    Number of bytes to copy.
 310  *
 311  * Context: User context only.  This function may sleep.
 312  *
 313  * Copy data from user space to kernel space.  Caller must check
 314  * the specified block with access_ok() before calling this function.
 315  *
 316  * Returns number of bytes that could not be copied.
 317  * On success, this will be zero.
 318  *
 319  * If some data could not be copied, this function will pad the copied
 320  * data to the requested size using zero bytes.
 321  */
 322 static inline unsigned long
 323 __copy_from_user(void *to, const void __user *from, unsigned long n)
 324 {
 325         return __copy_from_user_asm(to, n, from);
 326 }
 327
 328 /**
 329  * copy_from_user: - Copy a block of data from user space.
 330  * @to:   Destination address, in kernel space.
 331  * @from: Source address, in user space.
 332  * @n:    Number of bytes to copy.
 333  *
 334  * Context: User context only.  This function may sleep.
 335  *
 336  * Copy data from user space to kernel space.
 337  *
 338  * Returns number of bytes that could not be copied.
 339  * On success, this will be zero.
 340  *
 341  * If some data could not be copied, this function will pad the copied
 342  * data to the requested size using zero bytes.
 343  */
 344 static inline unsigned long
 345 copy_from_user(void *to, const void __user *from, unsigned long n)
 346 {
 347         might_sleep();
 348         if (access_ok(VERIFY_READ, from, n))
 349                 n = __copy_from_user(to, from, n);
 350         else
 351                 memset(to, 0, n);
 352         return n;
 353 }
 354
 355 extern unsigned long __copy_in_user_asm(const void __user *from, long n,
 356                                                         void __user *to);
 357
 358 static inline unsigned long
 359 __copy_in_user(void __user *to, const void __user *from, unsigned long n)
 360 {
 361         return __copy_in_user_asm(from, n, to);
 362 }
 363
 364 static inline unsigned long
 365 copy_in_user(void __user *to, const void __user *from, unsigned long n)
 366 {
 367         might_sleep();
 368         if (__access_ok(from,n) && __access_ok(to,n))
 369                 n = __copy_in_user_asm(from, n, to);
 370         return n;
 371 }
 372
 373 /*
 374  * Copy a null terminated string from userspace.
 375  */
 376 extern long __strncpy_from_user_asm(long count, char *dst,
 377                                         const char __user *src);
 378
 379 static inline long
 380 strncpy_from_user(char *dst, const char __user *src, long count)
 381 {
 382         long res = -EFAULT;
 383         might_sleep();
 384         if (access_ok(VERIFY_READ, src, 1))
 385                 res = __strncpy_from_user_asm(count, dst, src);
 386         return res;
 387 }
 388
 389
 390 extern long __strnlen_user_asm(long count, const char __user *src);
 391
 392 static inline unsigned long
 393 strnlen_user(const char __user * src, unsigned long n)
 394 {
 395         might_sleep();
 396         return __strnlen_user_asm(n, src);
 397 }
 398
 399 /**
 400  * strlen_user: - Get the size of a string in user space.
 401  * @str: The string to measure.
 402  *
 403  * Context: User context only.  This function may sleep.
 404  *
 405  * Get the size of a NUL-terminated string in user space.
 406  *
 407  * Returns the size of the string INCLUDING the terminating NUL.
 408  * On exception, returns 0.
 409  *
 410  * If there is a limit on the length of a valid string, you may wish to
 411  * consider using strnlen_user() instead.
 412  */
 413 #define strlen_user(str) strnlen_user(str, ~0UL)
 414
 415 /*
 416  * Zero Userspace
 417  */
 418
 419 extern long __clear_user_asm(void __user *to, long n);
 420
 421 static inline unsigned long
 422 __clear_user(void __user *to, unsigned long n)
 423 {
 424         return __clear_user_asm(to, n);
 425 }
 426
 427 static inline unsigned long
 428 clear_user(void __user *to, unsigned long n)
 429 {
 430         might_sleep();
 431         if (access_ok(VERIFY_WRITE, to, n))
 432                 n = __clear_user_asm(to, n);
 433         return n;
 434 }
 435
 436 #endif /* __S390_UACCESS_H */