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 * addr, unsigned long size)
  69 {
  70         return access_ok(type,addr,size)?0:-EFAULT;
  71 }
  72
  73 /*
  74  * The exception table consists of pairs of addresses: the first is the
  75  * address of an instruction that is allowed to fault, and the second is
  76  * the address at which the program should continue.  No registers are
  77  * modified, so it is entirely up to the continuation code to figure out
  78  * what to do.
  79  *
  80  * All the routines below use bits of fixup code that are out of line
  81  * with the main instruction path.  This means when everything is well,
  82  * we don't even have to jump over them.  Further, they do not intrude
  83  * on our cache or tlb entries.
  84  */
  85
  86 struct exception_table_entry
  87 {
  88         unsigned long insn, fixup;
  89 };
  90
  91 #ifndef __s390x__
  92 #define __uaccess_fixup \
  93         ".section .fixup,\"ax\"\n"      \
  94         "2: lhi    %0,%4\n"             \
  95         "   bras   1,3f\n"              \
  96         "   .long  1b\n"                \
  97         "3: l      1,0(1)\n"            \
  98         "   br     1\n"                 \
  99         ".previous\n"                   \
 100         ".section __ex_table,\"a\"\n"   \
 101         "   .align 4\n"                 \
 102         "   .long  0b,2b\n"             \
 103         ".previous"
 104 #define __uaccess_clobber "cc", "1"
 105 #else /* __s390x__ */
 106 #define __uaccess_fixup \
 107         ".section .fixup,\"ax\"\n"      \
 108         "2: lghi   %0,%4\n"             \
 109         "   jg     1b\n"                \
 110         ".previous\n"                   \
 111         ".section __ex_table,\"a\"\n"   \
 112         "   .align 8\n"                 \
 113         "   .quad  0b,2b\n"             \
 114         ".previous"
 115 #define __uaccess_clobber "cc"
 116 #endif /* __s390x__ */
 117
 118 /*
 119  * These are the main single-value transfer routines.  They automatically
 120  * use the right size if we just have the right pointer type.
 121  */
 122 #if __GNUC__ > 2
 123 #define __put_user_asm(x, ptr, err) \
 124 ({                                                              \
 125         err = 0;                                                \
 126         asm volatile(                                           \
 127                 "0: mvcs  0(%1,%2),%3,%0\n"                     \
 128                 "1:\n"                                          \
 129                 __uaccess_fixup                                 \
 130                 : "+&d" (err)                                   \
 131                 : "d" (sizeof(*(ptr))), "a" (ptr), "Q" (x),     \
 132                   "K" (-EFAULT)                                 \
 133                 : __uaccess_clobber );                          \
 134 })
 135 #else
 136 #define __put_user_asm(x, ptr, err) \
 137 ({                                                              \
 138         err = 0;                                                \
 139         asm volatile(                                           \
 140                 "0: mvcs  0(%1,%2),0(%3),%0\n"                  \
 141                 "1:\n"                                          \
 142                 __uaccess_fixup                                 \
 143                 : "+&d" (err)                                   \
 144                 : "d" (sizeof(*(ptr))), "a" (ptr), "a" (&(x)),  \
 145                   "K" (-EFAULT), "m" (x)                        \
 146                 : __uaccess_clobber );                          \
 147 })
 148 #endif
 149
 150 #define __put_user(x, ptr) \
 151 ({                                                              \
 152         __typeof__(*(ptr)) __x = (x);                           \
 153         int __pu_err;                                           \
 154         switch (sizeof (*(ptr))) {                              \
 155         case 1:                                                 \
 156         case 2:                                                 \
 157         case 4:                                                 \
 158         case 8:                                                 \
 159                 __put_user_asm(__x, ptr, __pu_err);             \
 160                 break;                                          \
 161         default:                                                \
 162                 __pu_err = __put_user_bad();                    \
 163                 break;                                          \
 164          }                                                      \
 165         __pu_err;                                               \
 166 })
 167
 168 #define put_user(x, ptr)                                        \
 169 ({                                                              \
 170         might_sleep();                                          \
 171         __put_user(x, ptr);                                     \
 172 })
 173
 174
 175 extern int __put_user_bad(void);
 176
 177 #if __GNUC__ > 2
 178 #define __get_user_asm(x, ptr, err) \
 179 ({                                                              \
 180         err = 0;                                                \
 181         asm volatile (                                          \
 182                 "0: mvcp  %O1(%2,%R1),0(%3),%0\n"               \
 183                 "1:\n"                                          \
 184                 __uaccess_fixup                                 \
 185                 : "+&d" (err), "=Q" (x)                         \
 186                 : "d" (sizeof(*(ptr))), "a" (ptr),              \
 187                   "K" (-EFAULT)                                 \
 188                 : __uaccess_clobber );                          \
 189 })
 190 #else
 191 #define __get_user_asm(x, ptr, err) \
 192 ({                                                              \
 193         err = 0;                                                \
 194         asm volatile (                                          \
 195                 "0: mvcp  0(%2,%5),0(%3),%0\n"                  \
 196                 "1:\n"                                          \
 197                 __uaccess_fixup                                 \
 198                 : "+&d" (err), "=m" (x)                         \
 199                 : "d" (sizeof(*(ptr))), "a" (ptr),              \
 200                   "K" (-EFAULT), "a" (&(x))                     \
 201                 : __uaccess_clobber );                          \
 202 })
 203 #endif
 204
 205 #define __get_user(x, ptr)                                      \
 206 ({                                                              \
 207         __typeof__(*(ptr)) __x;                                 \
 208         int __gu_err;                                           \
 209         switch (sizeof(*(ptr))) {                               \
 210         case 1:                                                 \
 211         case 2:                                                 \
 212         case 4:                                                 \
 213         case 8:                                                 \
 214                 __get_user_asm(__x, ptr, __gu_err);             \
 215                 break;                                          \
 216         default:                                                \
 217                 __x = 0;                                        \
 218                 __gu_err = __get_user_bad();                    \
 219                 break;                                          \
 220         }                                                       \
 221         (x) = __x;                                              \
 222         __gu_err;                                               \
 223 })
 224
 225 #define get_user(x, ptr)                                        \
 226 ({                                                              \
 227         might_sleep();                                          \
 228         __get_user(x, ptr);                                     \
 229 })
 230
 231 extern int __get_user_bad(void);
 232
 233 extern long __copy_to_user_asm(const void *from, long n, void *to);
 234
 235 /**
 236  * __copy_to_user: - Copy a block of data into user space, with less checking.
 237  * @to:   Destination address, in user space.
 238  * @from: Source address, in kernel space.
 239  * @n:    Number of bytes to copy.
 240  *
 241  * Context: User context only.  This function may sleep.
 242  *
 243  * Copy data from kernel space to user space.  Caller must check
 244  * the specified block with access_ok() before calling this function.
 245  *
 246  * Returns number of bytes that could not be copied.
 247  * On success, this will be zero.
 248  */
 249 static inline unsigned long
 250 __copy_to_user(void __user *to, const void *from, unsigned long n)
 251 {
 252         return __copy_to_user_asm(from, n, to);
 253 }
 254
 255 /**
 256  * copy_to_user: - Copy a block of data into user space.
 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.
 264  *
 265  * Returns number of bytes that could not be copied.
 266  * On success, this will be zero.
 267  */
 268 static inline unsigned long
 269 copy_to_user(void __user *to, const void *from, unsigned long n)
 270 {
 271         might_sleep();
 272         if (access_ok(VERIFY_WRITE, to, n))
 273                 n = __copy_to_user(to, from, n);
 274         return n;
 275 }
 276
 277 extern long __copy_from_user_asm(void *to, long n, const void *from);
 278
 279 /**
 280  * __copy_from_user: - Copy a block of data from user space, with less checking.
 281  * @to:   Destination address, in kernel space.
 282  * @from: Source address, in user space.
 283  * @n:    Number of bytes to copy.
 284  *
 285  * Context: User context only.  This function may sleep.
 286  *
 287  * Copy data from user space to kernel space.  Caller must check
 288  * the specified block with access_ok() before calling this function.
 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
 297 __copy_from_user(void *to, const void __user *from, unsigned long n)
 298 {
 299         return __copy_from_user_asm(to, n, from);
 300 }
 301
 302 /**
 303  * copy_from_user: - Copy a block of data from user space.
 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.
 311  *
 312  * Returns number of bytes that could not be copied.
 313  * On success, this will be zero.
 314  *
 315  * If some data could not be copied, this function will pad the copied
 316  * data to the requested size using zero bytes.
 317  */
 318 static inline unsigned long
 319 copy_from_user(void *to, const void __user *from, unsigned long n)
 320 {
 321         might_sleep();
 322         if (access_ok(VERIFY_READ, from, n))
 323                 n = __copy_from_user(to, from, n);
 324         else
 325                 memset(to, 0, n);
 326         return n;
 327 }
 328
 329 extern long __copy_in_user_asm(const void *from, long n, void *to);
 330
 331 static inline unsigned long
 332 __copy_in_user(void __user *to, const void __user *from, unsigned long n)
 333 {
 334         __copy_in_user_asm(from, n, to);
 335 }
 336
 337 static inline unsigned long
 338 copy_in_user(void __user *to, const void __user *from, unsigned long n)
 339 {
 340         might_sleep();
 341         if (__access_ok(from,n) && __access_ok(to,n))
 342                 n = __copy_in_user_asm(from, n, to);
 343         return n;
 344 }
 345
 346 /*
 347  * Copy a null terminated string from userspace.
 348  */
 349 extern long __strncpy_from_user_asm(char *dst, const char *src, long count);
 350
 351 static inline long
 352 strncpy_from_user(char *dst, const char *src, long count)
 353 {
 354         long res = -EFAULT;
 355         might_sleep();
 356         if (access_ok(VERIFY_READ, src, 1))
 357                 res = __strncpy_from_user_asm(dst, src, count);
 358         return res;
 359 }
 360
 361
 362 extern long __strnlen_user_asm(const char *src, long count);
 363
 364 static inline unsigned long
 365 strnlen_user(const char * src, unsigned long n)
 366 {
 367         might_sleep();
 368         return __strnlen_user_asm(src, n);
 369 }
 370
 371 /**
 372  * strlen_user: - Get the size of a string in user space.
 373  * @str: The string to measure.
 374  *
 375  * Context: User context only.  This function may sleep.
 376  *
 377  * Get the size of a NUL-terminated string in user space.
 378  *
 379  * Returns the size of the string INCLUDING the terminating NUL.
 380  * On exception, returns 0.
 381  *
 382  * If there is a limit on the length of a valid string, you may wish to
 383  * consider using strnlen_user() instead.
 384  */
 385 #define strlen_user(str) strnlen_user(str, ~0UL)
 386
 387 /*
 388  * Zero Userspace
 389  */
 390
 391 extern long __clear_user_asm(void *to, long n);
 392
 393 static inline unsigned long
 394 __clear_user(void *to, unsigned long n)
 395 {
 396         return __clear_user_asm(to, n);
 397 }
 398
 399 static inline unsigned long
 400 clear_user(void *to, unsigned long n)
 401 {
 402         might_sleep();
 403         if (access_ok(VERIFY_WRITE, to, n))
 404                 n = __clear_user_asm(to, n);
 405         return n;
 406 }
 407
 408 #endif /* __S390_UACCESS_H */