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