kernel/arch/s390/include/asm/uaccess.h

   1 /*
   2  *  S390 version
   3  *    Copyright IBM Corp. 1999, 2000
   4  *    Author(s): Hartmut Penner (hp@de.ibm.com),
   5  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   6  *
   7  *  Derived from "include/asm-i386/uaccess.h"
   8  */
   9 #ifndef __S390_UACCESS_H
  10 #define __S390_UACCESS_H
  11
  12 /*
  13  * User space memory access functions
  14  */
  15 #include <linux/sched.h>
  16 #include <linux/errno.h>
  17 #include <asm/ctl_reg.h>
  18
  19 #define VERIFY_READ     0
  20 #define VERIFY_WRITE    1
  21
  22
  23 /*
  24  * The fs value determines whether argument validity checking should be
  25  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  26  * get_fs() == KERNEL_DS, checking is bypassed.
  27  *
  28  * For historical reasons, these macros are grossly misnamed.
  29  */
  30
  31 #define MAKE_MM_SEG(a)  ((mm_segment_t) { (a) })
  32
  33
  34 #define KERNEL_DS       MAKE_MM_SEG(0)
  35 #define USER_DS         MAKE_MM_SEG(1)
  36
  37 #define get_ds()        (KERNEL_DS)
  38 #define get_fs()        (current->thread.mm_segment)
  39
  40 #define set_fs(x) \
  41 ({                                                                      \
  42         unsigned long __pto;                                            \
  43         current->thread.mm_segment = (x);                               \
  44         __pto = current->thread.mm_segment.ar4 ?                        \
  45                 S390_lowcore.user_asce : S390_lowcore.kernel_asce;      \
  46         __ctl_load(__pto, 7, 7);                                        \
  47 })
  48
  49 #define segment_eq(a,b) ((a).ar4 == (b).ar4)
  50
  51 static inline int __range_ok(unsigned long addr, unsigned long size)
  52 {
  53         return 1;
  54 }
  55
  56 #define __access_ok(addr, size)                         \
  57 ({                                                      \
  58         __chk_user_ptr(addr);                           \
  59         __range_ok((unsigned long)(addr), (size));      \
  60 })
  61
  62 #define access_ok(type, addr, size) __access_ok(addr, size)
  63
  64 /*
  65  * The exception table consists of pairs of addresses: the first is the
  66  * address of an instruction that is allowed to fault, and the second is
  67  * the address at which the program should continue.  No registers are
  68  * modified, so it is entirely up to the continuation code to figure out
  69  * what to do.
  70  *
  71  * All the routines below use bits of fixup code that are out of line
  72  * with the main instruction path.  This means when everything is well,
  73  * we don't even have to jump over them.  Further, they do not intrude
  74  * on our cache or tlb entries.
  75  */
  76
  77 struct exception_table_entry
  78 {
  79         int insn, fixup;
  80 };
  81
  82 static inline unsigned long extable_insn(const struct exception_table_entry *x)
  83 {
  84         return (unsigned long)&x->insn + x->insn;
  85 }
  86
  87 static inline unsigned long extable_fixup(const struct exception_table_entry *x)
  88 {
  89         return (unsigned long)&x->fixup + x->fixup;
  90 }
  91
  92 #define ARCH_HAS_SORT_EXTABLE
  93 #define ARCH_HAS_SEARCH_EXTABLE
  94
  95 /**
  96  * __copy_from_user: - Copy a block of data from user space, with less checking.
  97  * @to:   Destination address, in kernel space.
  98  * @from: Source address, in user space.
  99  * @n:    Number of bytes to copy.
 100  *
 101  * Context: User context only. This function may sleep if pagefaults are
 102  *          enabled.
 103  *
 104  * Copy data from user space to kernel space.  Caller must check
 105  * the specified block with access_ok() before calling this function.
 106  *
 107  * Returns number of bytes that could not be copied.
 108  * On success, this will be zero.
 109  *
 110  * If some data could not be copied, this function will pad the copied
 111  * data to the requested size using zero bytes.
 112  */
 113 unsigned long __must_check __copy_from_user(void *to, const void __user *from,
 114                                             unsigned long n);
 115
 116 /**
 117  * __copy_to_user: - Copy a block of data into user space, with less checking.
 118  * @to:   Destination address, in user space.
 119  * @from: Source address, in kernel space.
 120  * @n:    Number of bytes to copy.
 121  *
 122  * Context: User context only. This function may sleep if pagefaults are
 123  *          enabled.
 124  *
 125  * Copy data from kernel space to user space.  Caller must check
 126  * the specified block with access_ok() before calling this function.
 127  *
 128  * Returns number of bytes that could not be copied.
 129  * On success, this will be zero.
 130  */
 131 unsigned long __must_check __copy_to_user(void __user *to, const void *from,
 132                                           unsigned long n);
 133
 134 #define __copy_to_user_inatomic __copy_to_user
 135 #define __copy_from_user_inatomic __copy_from_user
 136
 137 #ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
 138
 139 #define __put_get_user_asm(to, from, size, spec)                \
 140 ({                                                              \
 141         register unsigned long __reg0 asm("0") = spec;          \
 142         int __rc;                                               \
 143                                                                 \
 144         asm volatile(                                           \
 145                 "0:     mvcos   %1,%3,%2\n"                     \
 146                 "1:     xr      %0,%0\n"                        \
 147                 "2:\n"                                          \
 148                 ".pushsection .fixup, \"ax\"\n"                 \
 149                 "3:     lhi     %0,%5\n"                        \
 150                 "       jg      2b\n"                           \
 151                 ".popsection\n"                                 \
 152                 EX_TABLE(0b,3b) EX_TABLE(1b,3b)                 \
 153                 : "=d" (__rc), "=Q" (*(to))                     \
 154                 : "d" (size), "Q" (*(from)),                    \
 155                   "d" (__reg0), "K" (-EFAULT)                   \
 156                 : "cc");                                        \
 157         __rc;                                                   \
 158 })
 159
 160 #define __put_user_fn(x, ptr, size) __put_get_user_asm(ptr, x, size, 0x810000UL)
 161 #define __get_user_fn(x, ptr, size) __put_get_user_asm(x, ptr, size, 0x81UL)
 162
 163 #else /* CONFIG_HAVE_MARCH_Z10_FEATURES */
 164
 165 static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
 166 {
 167         size = __copy_to_user(ptr, x, size);
 168         return size ? -EFAULT : 0;
 169 }
 170
 171 static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
 172 {
 173         size = __copy_from_user(x, ptr, size);
 174         return size ? -EFAULT : 0;
 175 }
 176
 177 #endif /* CONFIG_HAVE_MARCH_Z10_FEATURES */
 178
 179 /*
 180  * These are the main single-value transfer routines.  They automatically
 181  * use the right size if we just have the right pointer type.
 182  */
 183 #define __put_user(x, ptr) \
 184 ({                                                              \
 185         __typeof__(*(ptr)) __x = (x);                           \
 186         int __pu_err = -EFAULT;                                 \
 187         __chk_user_ptr(ptr);                                    \
 188         switch (sizeof (*(ptr))) {                              \
 189         case 1:                                                 \
 190         case 2:                                                 \
 191         case 4:                                                 \
 192         case 8:                                                 \
 193                 __pu_err = __put_user_fn(&__x, ptr,             \
 194                                          sizeof(*(ptr)));       \
 195                 break;                                          \
 196         default:                                                \
 197                 __put_user_bad();                               \
 198                 break;                                          \
 199          }                                                      \
 200         __pu_err;                                               \
 201 })
 202
 203 #define put_user(x, ptr)                                        \
 204 ({                                                              \
 205         might_fault();                                          \
 206         __put_user(x, ptr);                                     \
 207 })
 208
 209
 210 int __put_user_bad(void) __attribute__((noreturn));
 211
 212 #define __get_user(x, ptr)                                      \
 213 ({                                                              \
 214         int __gu_err = -EFAULT;                                 \
 215         __chk_user_ptr(ptr);                                    \
 216         switch (sizeof(*(ptr))) {                               \
 217         case 1: {                                               \
 218                 unsigned char __x;                              \
 219                 __gu_err = __get_user_fn(&__x, ptr,             \
 220                                          sizeof(*(ptr)));       \
 221                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 222                 break;                                          \
 223         };                                                      \
 224         case 2: {                                               \
 225                 unsigned short __x;                             \
 226                 __gu_err = __get_user_fn(&__x, ptr,             \
 227                                          sizeof(*(ptr)));       \
 228                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 229                 break;                                          \
 230         };                                                      \
 231         case 4: {                                               \
 232                 unsigned int __x;                               \
 233                 __gu_err = __get_user_fn(&__x, ptr,             \
 234                                          sizeof(*(ptr)));       \
 235                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 236                 break;                                          \
 237         };                                                      \
 238         case 8: {                                               \
 239                 unsigned long long __x;                         \
 240                 __gu_err = __get_user_fn(&__x, ptr,             \
 241                                          sizeof(*(ptr)));       \
 242                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 243                 break;                                          \
 244         };                                                      \
 245         default:                                                \
 246                 __get_user_bad();                               \
 247                 break;                                          \
 248         }                                                       \
 249         __gu_err;                                               \
 250 })
 251
 252 #define get_user(x, ptr)                                        \
 253 ({                                                              \
 254         might_fault();                                          \
 255         __get_user(x, ptr);                                     \
 256 })
 257
 258 int __get_user_bad(void) __attribute__((noreturn));
 259
 260 #define __put_user_unaligned __put_user
 261 #define __get_user_unaligned __get_user
 262
 263 /**
 264  * copy_to_user: - Copy a block of data into user space.
 265  * @to:   Destination address, in user space.
 266  * @from: Source address, in kernel space.
 267  * @n:    Number of bytes to copy.
 268  *
 269  * Context: User context only. This function may sleep if pagefaults are
 270  *          enabled.
 271  *
 272  * Copy data from kernel space to user space.
 273  *
 274  * Returns number of bytes that could not be copied.
 275  * On success, this will be zero.
 276  */
 277 static inline unsigned long __must_check
 278 copy_to_user(void __user *to, const void *from, unsigned long n)
 279 {
 280         might_fault();
 281         return __copy_to_user(to, from, n);
 282 }
 283
 284 void copy_from_user_overflow(void)
 285 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
 286 __compiletime_warning("copy_from_user() buffer size is not provably correct")
 287 #endif
 288 ;
 289
 290 /**
 291  * copy_from_user: - Copy a block of data from user space.
 292  * @to:   Destination address, in kernel space.
 293  * @from: Source address, in user space.
 294  * @n:    Number of bytes to copy.
 295  *
 296  * Context: User context only. This function may sleep if pagefaults are
 297  *          enabled.
 298  *
 299  * Copy data from user space to kernel space.
 300  *
 301  * Returns number of bytes that could not be copied.
 302  * On success, this will be zero.
 303  *
 304  * If some data could not be copied, this function will pad the copied
 305  * data to the requested size using zero bytes.
 306  */
 307 static inline unsigned long __must_check
 308 copy_from_user(void *to, const void __user *from, unsigned long n)
 309 {
 310         unsigned int sz = __compiletime_object_size(to);
 311
 312         might_fault();
 313         if (unlikely(sz != -1 && sz < n)) {
 314                 copy_from_user_overflow();
 315                 return n;
 316         }
 317         return __copy_from_user(to, from, n);
 318 }
 319
 320 unsigned long __must_check
 321 __copy_in_user(void __user *to, const void __user *from, unsigned long n);
 322
 323 static inline unsigned long __must_check
 324 copy_in_user(void __user *to, const void __user *from, unsigned long n)
 325 {
 326         might_fault();
 327         return __copy_in_user(to, from, n);
 328 }
 329
 330 /*
 331  * Copy a null terminated string from userspace.
 332  */
 333
 334 long __strncpy_from_user(char *dst, const char __user *src, long count);
 335
 336 static inline long __must_check
 337 strncpy_from_user(char *dst, const char __user *src, long count)
 338 {
 339         might_fault();
 340         return __strncpy_from_user(dst, src, count);
 341 }
 342
 343 unsigned long __must_check __strnlen_user(const char __user *src, unsigned long count);
 344
 345 static inline unsigned long strnlen_user(const char __user *src, unsigned long n)
 346 {
 347         might_fault();
 348         return __strnlen_user(src, n);
 349 }
 350
 351 /**
 352  * strlen_user: - Get the size of a string in user space.
 353  * @str: The string to measure.
 354  *
 355  * Context: User context only. This function may sleep if pagefaults are
 356  *          enabled.
 357  *
 358  * Get the size of a NUL-terminated string in user space.
 359  *
 360  * Returns the size of the string INCLUDING the terminating NUL.
 361  * On exception, returns 0.
 362  *
 363  * If there is a limit on the length of a valid string, you may wish to
 364  * consider using strnlen_user() instead.
 365  */
 366 #define strlen_user(str) strnlen_user(str, ~0UL)
 367
 368 /*
 369  * Zero Userspace
 370  */
 371 unsigned long __must_check __clear_user(void __user *to, unsigned long size);
 372
 373 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
 374 {
 375         might_fault();
 376         return __clear_user(to, n);
 377 }
 378
 379 int copy_to_user_real(void __user *dest, void *src, unsigned long count);
 380 void s390_kernel_write(void *dst, const void *src, size_t size);
 381
 382 #endif /* __S390_UACCESS_H */