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_fixup(const struct exception_table_entry *x)
  83 {
  84         return (unsigned long)&x->fixup + x->fixup;
  85 }
  86
  87 #define ARCH_HAS_RELATIVE_EXTABLE
  88
  89 /**
  90  * __copy_from_user: - Copy a block of data from user space, with less checking.
  91  * @to:   Destination address, in kernel space.
  92  * @from: Source address, in user space.
  93  * @n:    Number of bytes to copy.
  94  *
  95  * Context: User context only. This function may sleep if pagefaults are
  96  *          enabled.
  97  *
  98  * Copy data from user space to kernel space.  Caller must check
  99  * the specified block with access_ok() before calling this function.
 100  *
 101  * Returns number of bytes that could not be copied.
 102  * On success, this will be zero.
 103  *
 104  * If some data could not be copied, this function will pad the copied
 105  * data to the requested size using zero bytes.
 106  */
 107 unsigned long __must_check __copy_from_user(void *to, const void __user *from,
 108                                             unsigned long n);
 109
 110 /**
 111  * __copy_to_user: - Copy a block of data into user space, with less checking.
 112  * @to:   Destination address, in user space.
 113  * @from: Source address, in kernel space.
 114  * @n:    Number of bytes to copy.
 115  *
 116  * Context: User context only. This function may sleep if pagefaults are
 117  *          enabled.
 118  *
 119  * Copy data from kernel space to user space.  Caller must check
 120  * the specified block with access_ok() before calling this function.
 121  *
 122  * Returns number of bytes that could not be copied.
 123  * On success, this will be zero.
 124  */
 125 unsigned long __must_check __copy_to_user(void __user *to, const void *from,
 126                                           unsigned long n);
 127
 128 #define __copy_to_user_inatomic __copy_to_user
 129 #define __copy_from_user_inatomic __copy_from_user
 130
 131 #ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
 132
 133 #define __put_get_user_asm(to, from, size, spec)                \
 134 ({                                                              \
 135         register unsigned long __reg0 asm("0") = spec;          \
 136         int __rc;                                               \
 137                                                                 \
 138         asm volatile(                                           \
 139                 "0:     mvcos   %1,%3,%2\n"                     \
 140                 "1:     xr      %0,%0\n"                        \
 141                 "2:\n"                                          \
 142                 ".pushsection .fixup, \"ax\"\n"                 \
 143                 "3:     lhi     %0,%5\n"                        \
 144                 "       jg      2b\n"                           \
 145                 ".popsection\n"                                 \
 146                 EX_TABLE(0b,3b) EX_TABLE(1b,3b)                 \
 147                 : "=d" (__rc), "=Q" (*(to))                     \
 148                 : "d" (size), "Q" (*(from)),                    \
 149                   "d" (__reg0), "K" (-EFAULT)                   \
 150                 : "cc");                                        \
 151         __rc;                                                   \
 152 })
 153
 154 #define __put_user_fn(x, ptr, size) __put_get_user_asm(ptr, x, size, 0x810000UL)
 155 #define __get_user_fn(x, ptr, size) __put_get_user_asm(x, ptr, size, 0x81UL)
 156
 157 #else /* CONFIG_HAVE_MARCH_Z10_FEATURES */
 158
 159 static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
 160 {
 161         size = __copy_to_user(ptr, x, size);
 162         return size ? -EFAULT : 0;
 163 }
 164
 165 static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
 166 {
 167         size = __copy_from_user(x, ptr, size);
 168         return size ? -EFAULT : 0;
 169 }
 170
 171 #endif /* CONFIG_HAVE_MARCH_Z10_FEATURES */
 172
 173 /*
 174  * These are the main single-value transfer routines.  They automatically
 175  * use the right size if we just have the right pointer type.
 176  */
 177 #define __put_user(x, ptr) \
 178 ({                                                              \
 179         __typeof__(*(ptr)) __x = (x);                           \
 180         int __pu_err = -EFAULT;                                 \
 181         __chk_user_ptr(ptr);                                    \
 182         switch (sizeof (*(ptr))) {                              \
 183         case 1:                                                 \
 184         case 2:                                                 \
 185         case 4:                                                 \
 186         case 8:                                                 \
 187                 __pu_err = __put_user_fn(&__x, ptr,             \
 188                                          sizeof(*(ptr)));       \
 189                 break;                                          \
 190         default:                                                \
 191                 __put_user_bad();                               \
 192                 break;                                          \
 193          }                                                      \
 194         __pu_err;                                               \
 195 })
 196
 197 #define put_user(x, ptr)                                        \
 198 ({                                                              \
 199         might_fault();                                          \
 200         __put_user(x, ptr);                                     \
 201 })
 202
 203
 204 int __put_user_bad(void) __attribute__((noreturn));
 205
 206 #define __get_user(x, ptr)                                      \
 207 ({                                                              \
 208         int __gu_err = -EFAULT;                                 \
 209         __chk_user_ptr(ptr);                                    \
 210         switch (sizeof(*(ptr))) {                               \
 211         case 1: {                                               \
 212                 unsigned char __x;                              \
 213                 __gu_err = __get_user_fn(&__x, ptr,             \
 214                                          sizeof(*(ptr)));       \
 215                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 216                 break;                                          \
 217         };                                                      \
 218         case 2: {                                               \
 219                 unsigned short __x;                             \
 220                 __gu_err = __get_user_fn(&__x, ptr,             \
 221                                          sizeof(*(ptr)));       \
 222                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 223                 break;                                          \
 224         };                                                      \
 225         case 4: {                                               \
 226                 unsigned int __x;                               \
 227                 __gu_err = __get_user_fn(&__x, ptr,             \
 228                                          sizeof(*(ptr)));       \
 229                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 230                 break;                                          \
 231         };                                                      \
 232         case 8: {                                               \
 233                 unsigned long long __x;                         \
 234                 __gu_err = __get_user_fn(&__x, ptr,             \
 235                                          sizeof(*(ptr)));       \
 236                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 237                 break;                                          \
 238         };                                                      \
 239         default:                                                \
 240                 __get_user_bad();                               \
 241                 break;                                          \
 242         }                                                       \
 243         __gu_err;                                               \
 244 })
 245
 246 #define get_user(x, ptr)                                        \
 247 ({                                                              \
 248         might_fault();                                          \
 249         __get_user(x, ptr);                                     \
 250 })
 251
 252 int __get_user_bad(void) __attribute__((noreturn));
 253
 254 #define __put_user_unaligned __put_user
 255 #define __get_user_unaligned __get_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 if pagefaults are
 264  *          enabled.
 265  *
 266  * Copy data from kernel space to user space.
 267  *
 268  * Returns number of bytes that could not be copied.
 269  * On success, this will be zero.
 270  */
 271 static inline unsigned long __must_check
 272 copy_to_user(void __user *to, const void *from, unsigned long n)
 273 {
 274         might_fault();
 275         return __copy_to_user(to, from, n);
 276 }
 277
 278 void copy_from_user_overflow(void)
 279 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
 280 __compiletime_warning("copy_from_user() buffer size is not provably correct")
 281 #endif
 282 ;
 283
 284 /**
 285  * copy_from_user: - Copy a block of data from user space.
 286  * @to:   Destination address, in kernel space.
 287  * @from: Source address, in user space.
 288  * @n:    Number of bytes to copy.
 289  *
 290  * Context: User context only. This function may sleep if pagefaults are
 291  *          enabled.
 292  *
 293  * Copy data from user space to kernel space.
 294  *
 295  * Returns number of bytes that could not be copied.
 296  * On success, this will be zero.
 297  *
 298  * If some data could not be copied, this function will pad the copied
 299  * data to the requested size using zero bytes.
 300  */
 301 static inline unsigned long __must_check
 302 copy_from_user(void *to, const void __user *from, unsigned long n)
 303 {
 304         unsigned int sz = __compiletime_object_size(to);
 305
 306         might_fault();
 307         if (unlikely(sz != -1 && sz < n)) {
 308                 copy_from_user_overflow();
 309                 return n;
 310         }
 311         return __copy_from_user(to, from, n);
 312 }
 313
 314 unsigned long __must_check
 315 __copy_in_user(void __user *to, const void __user *from, unsigned long n);
 316
 317 static inline unsigned long __must_check
 318 copy_in_user(void __user *to, const void __user *from, unsigned long n)
 319 {
 320         might_fault();
 321         return __copy_in_user(to, from, n);
 322 }
 323
 324 /*
 325  * Copy a null terminated string from userspace.
 326  */
 327
 328 long __strncpy_from_user(char *dst, const char __user *src, long count);
 329
 330 static inline long __must_check
 331 strncpy_from_user(char *dst, const char __user *src, long count)
 332 {
 333         might_fault();
 334         return __strncpy_from_user(dst, src, count);
 335 }
 336
 337 unsigned long __must_check __strnlen_user(const char __user *src, unsigned long count);
 338
 339 static inline unsigned long strnlen_user(const char __user *src, unsigned long n)
 340 {
 341         might_fault();
 342         return __strnlen_user(src, n);
 343 }
 344
 345 /**
 346  * strlen_user: - Get the size of a string in user space.
 347  * @str: The string to measure.
 348  *
 349  * Context: User context only. This function may sleep if pagefaults are
 350  *          enabled.
 351  *
 352  * Get the size of a NUL-terminated string in user space.
 353  *
 354  * Returns the size of the string INCLUDING the terminating NUL.
 355  * On exception, returns 0.
 356  *
 357  * If there is a limit on the length of a valid string, you may wish to
 358  * consider using strnlen_user() instead.
 359  */
 360 #define strlen_user(str) strnlen_user(str, ~0UL)
 361
 362 /*
 363  * Zero Userspace
 364  */
 365 unsigned long __must_check __clear_user(void __user *to, unsigned long size);
 366
 367 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
 368 {
 369         might_fault();
 370         return __clear_user(to, n);
 371 }
 372
 373 int copy_to_user_real(void __user *dest, void *src, unsigned long count);
 374 void s390_kernel_write(void *dst, const void *src, size_t size);
 375
 376 #endif /* __S390_UACCESS_H */