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