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 extern inline int verify_area(int type, const void __user *addr,
  69                                                 unsigned long size)
  70 {
  71         return access_ok(type, addr, size) ? 0 : -EFAULT;
  72 }
  73
  74 /*
  75  * The exception table consists of pairs of addresses: the first is the
  76  * address of an instruction that is allowed to fault, and the second is
  77  * the address at which the program should continue.  No registers are
  78  * modified, so it is entirely up to the continuation code to figure out
  79  * what to do.
  80  *
  81  * All the routines below use bits of fixup code that are out of line
  82  * with the main instruction path.  This means when everything is well,
  83  * we don't even have to jump over them.  Further, they do not intrude
  84  * on our cache or tlb entries.
  85  */
  86
  87 struct exception_table_entry
  88 {
  89         unsigned long insn, fixup;
  90 };
  91
  92 #ifndef __s390x__
  93 #define __uaccess_fixup \
  94         ".section .fixup,\"ax\"\n"      \
  95         "2: lhi    %0,%4\n"             \
  96         "   bras   1,3f\n"              \
  97         "   .long  1b\n"                \
  98         "3: l      1,0(1)\n"            \
  99         "   br     1\n"                 \
 100         ".previous\n"                   \
 101         ".section __ex_table,\"a\"\n"   \
 102         "   .align 4\n"                 \
 103         "   .long  0b,2b\n"             \
 104         ".previous"
 105 #define __uaccess_clobber "cc", "1"
 106 #else /* __s390x__ */
 107 #define __uaccess_fixup \
 108         ".section .fixup,\"ax\"\n"      \
 109         "2: lghi   %0,%4\n"             \
 110         "   jg     1b\n"                \
 111         ".previous\n"                   \
 112         ".section __ex_table,\"a\"\n"   \
 113         "   .align 8\n"                 \
 114         "   .quad  0b,2b\n"             \
 115         ".previous"
 116 #define __uaccess_clobber "cc"
 117 #endif /* __s390x__ */
 118
 119 /*
 120  * These are the main single-value transfer routines.  They automatically
 121  * use the right size if we just have the right pointer type.
 122  */
 123 #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
 124 #define __put_user_asm(x, ptr, err) \
 125 ({                                                              \
 126         err = 0;                                                \
 127         asm volatile(                                           \
 128                 "0: mvcs  0(%1,%2),%3,%0\n"                     \
 129                 "1:\n"                                          \
 130                 __uaccess_fixup                                 \
 131                 : "+&d" (err)                                   \
 132                 : "d" (sizeof(*(ptr))), "a" (ptr), "Q" (x),     \
 133                   "K" (-EFAULT)                                 \
 134                 : __uaccess_clobber );                          \
 135 })
 136 #else
 137 #define __put_user_asm(x, ptr, err) \
 138 ({                                                              \
 139         err = 0;                                                \
 140         asm volatile(                                           \
 141                 "0: mvcs  0(%1,%2),0(%3),%0\n"                  \
 142                 "1:\n"                                          \
 143                 __uaccess_fixup                                 \
 144                 : "+&d" (err)                                   \
 145                 : "d" (sizeof(*(ptr))), "a" (ptr), "a" (&(x)),  \
 146                   "K" (-EFAULT), "m" (x)                        \
 147                 : __uaccess_clobber );                          \
 148 })
 149 #endif
 150
 151 #ifndef __CHECKER__
 152 #define __put_user(x, ptr) \
 153 ({                                                              \
 154         __typeof__(*(ptr)) __x = (x);                           \
 155         int __pu_err;                                           \
 156         switch (sizeof (*(ptr))) {                              \
 157         case 1:                                                 \
 158         case 2:                                                 \
 159         case 4:                                                 \
 160         case 8:                                                 \
 161                 __put_user_asm(__x, ptr, __pu_err);             \
 162                 break;                                          \
 163         default:                                                \
 164                 __pu_err = __put_user_bad();                    \
 165                 break;                                          \
 166          }                                                      \
 167         __pu_err;                                               \
 168 })
 169 #else
 170 #define __put_user(x, ptr)                      \
 171 ({                                              \
 172         void __user *p;                         \
 173         p = (ptr);                              \
 174         0;                                      \
 175 })
 176 #endif
 177
 178 #define put_user(x, ptr)                                        \
 179 ({                                                              \
 180         might_sleep();                                          \
 181         __put_user(x, ptr);                                     \
 182 })
 183
 184
 185 extern int __put_user_bad(void);
 186
 187 #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
 188 #define __get_user_asm(x, ptr, err) \
 189 ({                                                              \
 190         err = 0;                                                \
 191         asm volatile (                                          \
 192                 "0: mvcp  %O1(%2,%R1),0(%3),%0\n"               \
 193                 "1:\n"                                          \
 194                 __uaccess_fixup                                 \
 195                 : "+&d" (err), "=Q" (x)                         \
 196                 : "d" (sizeof(*(ptr))), "a" (ptr),              \
 197                   "K" (-EFAULT)                                 \
 198                 : __uaccess_clobber );                          \
 199 })
 200 #else
 201 #define __get_user_asm(x, ptr, err) \
 202 ({                                                              \
 203         err = 0;                                                \
 204         asm volatile (                                          \
 205                 "0: mvcp  0(%2,%5),0(%3),%0\n"                  \
 206                 "1:\n"                                          \
 207                 __uaccess_fixup                                 \
 208                 : "+&d" (err), "=m" (x)                         \
 209                 : "d" (sizeof(*(ptr))), "a" (ptr),              \
 210                   "K" (-EFAULT), "a" (&(x))                     \
 211                 : __uaccess_clobber );                          \
 212 })
 213 #endif
 214
 215 #ifndef __CHECKER__
 216 #define __get_user(x, ptr)                                      \
 217 ({                                                              \
 218         __typeof__(*(ptr)) __x;                                 \
 219         int __gu_err;                                           \
 220         switch (sizeof(*(ptr))) {                               \
 221         case 1:                                                 \
 222         case 2:                                                 \
 223         case 4:                                                 \
 224         case 8:                                                 \
 225                 __get_user_asm(__x, ptr, __gu_err);             \
 226                 break;                                          \
 227         default:                                                \
 228                 __x = 0;                                        \
 229                 __gu_err = __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);
 252
 253 extern long __copy_to_user_asm(const void *from, long n, void __user *to);
 254
 255 /**
 256  * __copy_to_user: - Copy a block of data into user space, with less checking.
 257  * @to:   Destination address, in user space.
 258  * @from: Source address, in kernel space.
 259  * @n:    Number of bytes to copy.
 260  *
 261  * Context: User context only.  This function may sleep.
 262  *
 263  * Copy data from kernel space to user space.  Caller must check
 264  * the specified block with access_ok() before calling this function.
 265  *
 266  * Returns number of bytes that could not be copied.
 267  * On success, this will be zero.
 268  */
 269 static inline unsigned long
 270 __copy_to_user(void __user *to, const void *from, unsigned long n)
 271 {
 272         return __copy_to_user_asm(from, n, to);
 273 }
 274
 275 #define __copy_to_user_inatomic __copy_to_user
 276 #define __copy_from_user_inatomic __copy_from_user
 277
 278 /**
 279  * copy_to_user: - Copy a block of data into user space.
 280  * @to:   Destination address, in user space.
 281  * @from: Source address, in kernel space.
 282  * @n:    Number of bytes to copy.
 283  *
 284  * Context: User context only.  This function may sleep.
 285  *
 286  * Copy data from kernel space to user space.
 287  *
 288  * Returns number of bytes that could not be copied.
 289  * On success, this will be zero.
 290  */
 291 static inline unsigned long
 292 copy_to_user(void __user *to, const void *from, unsigned long n)
 293 {
 294         might_sleep();
 295         if (access_ok(VERIFY_WRITE, to, n))
 296                 n = __copy_to_user(to, from, n);
 297         return n;
 298 }
 299
 300 extern long __copy_from_user_asm(void *to, long n, const void __user *from);
 301
 302 /**
 303  * __copy_from_user: - Copy a block of data from user space, with less checking.
 304  * @to:   Destination address, in kernel space.
 305  * @from: Source address, in user space.
 306  * @n:    Number of bytes to copy.
 307  *
 308  * Context: User context only.  This function may sleep.
 309  *
 310  * Copy data from user space to kernel space.  Caller must check
 311  * the specified block with access_ok() before calling this function.
 312  *
 313  * Returns number of bytes that could not be copied.
 314  * On success, this will be zero.
 315  *
 316  * If some data could not be copied, this function will pad the copied
 317  * data to the requested size using zero bytes.
 318  */
 319 static inline unsigned long
 320 __copy_from_user(void *to, const void __user *from, unsigned long n)
 321 {
 322         return __copy_from_user_asm(to, n, from);
 323 }
 324
 325 /**
 326  * copy_from_user: - Copy a block of data from user space.
 327  * @to:   Destination address, in kernel space.
 328  * @from: Source address, in user space.
 329  * @n:    Number of bytes to copy.
 330  *
 331  * Context: User context only.  This function may sleep.
 332  *
 333  * Copy data from user space to kernel space.
 334  *
 335  * Returns number of bytes that could not be copied.
 336  * On success, this will be zero.
 337  *
 338  * If some data could not be copied, this function will pad the copied
 339  * data to the requested size using zero bytes.
 340  */
 341 static inline unsigned long
 342 copy_from_user(void *to, const void __user *from, unsigned long n)
 343 {
 344         might_sleep();
 345         if (access_ok(VERIFY_READ, from, n))
 346                 n = __copy_from_user(to, from, n);
 347         else
 348                 memset(to, 0, n);
 349         return n;
 350 }
 351
 352 extern unsigned long __copy_in_user_asm(const void __user *from, long n,
 353                                                         void __user *to);
 354
 355 static inline unsigned long
 356 __copy_in_user(void __user *to, const void __user *from, unsigned long n)
 357 {
 358         return __copy_in_user_asm(from, n, to);
 359 }
 360
 361 static inline unsigned long
 362 copy_in_user(void __user *to, const void __user *from, unsigned long n)
 363 {
 364         might_sleep();
 365         if (__access_ok(from,n) && __access_ok(to,n))
 366                 n = __copy_in_user_asm(from, n, to);
 367         return n;
 368 }
 369
 370 /*
 371  * Copy a null terminated string from userspace.
 372  */
 373 extern long __strncpy_from_user_asm(long count, char *dst,
 374                                         const char __user *src);
 375
 376 static inline long
 377 strncpy_from_user(char *dst, const char __user *src, long count)
 378 {
 379         long res = -EFAULT;
 380         might_sleep();
 381         if (access_ok(VERIFY_READ, src, 1))
 382                 res = __strncpy_from_user_asm(count, dst, src);
 383         return res;
 384 }
 385
 386
 387 extern long __strnlen_user_asm(long count, const char __user *src);
 388
 389 static inline unsigned long
 390 strnlen_user(const char __user * src, unsigned long n)
 391 {
 392         might_sleep();
 393         return __strnlen_user_asm(n, src);
 394 }
 395
 396 /**
 397  * strlen_user: - Get the size of a string in user space.
 398  * @str: The string to measure.
 399  *
 400  * Context: User context only.  This function may sleep.
 401  *
 402  * Get the size of a NUL-terminated string in user space.
 403  *
 404  * Returns the size of the string INCLUDING the terminating NUL.
 405  * On exception, returns 0.
 406  *
 407  * If there is a limit on the length of a valid string, you may wish to
 408  * consider using strnlen_user() instead.
 409  */
 410 #define strlen_user(str) strnlen_user(str, ~0UL)
 411
 412 /*
 413  * Zero Userspace
 414  */
 415
 416 extern long __clear_user_asm(void __user *to, long n);
 417
 418 static inline unsigned long
 419 __clear_user(void __user *to, unsigned long n)
 420 {
 421         return __clear_user_asm(to, n);
 422 }
 423
 424 static inline unsigned long
 425 clear_user(void __user *to, unsigned long n)
 426 {
 427         might_sleep();
 428         if (access_ok(VERIFY_WRITE, to, n))
 429                 n = __clear_user_asm(to, n);
 430         return n;
 431 }
 432
 433 #endif /* __S390_UACCESS_H */