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.
 102  *
 103  * Copy data from user space to kernel space.  Caller must check
 104  * the specified block with access_ok() before calling this function.
 105  *
 106  * Returns number of bytes that could not be copied.
 107  * On success, this will be zero.
 108  *
 109  * If some data could not be copied, this function will pad the copied
 110  * data to the requested size using zero bytes.
 111  */
 112 unsigned long __must_check __copy_from_user(void *to, const void __user *from,
 113                                             unsigned long n);
 114
 115 /**
 116  * __copy_to_user: - Copy a block of data into user space, with less checking.
 117  * @to:   Destination address, in user space.
 118  * @from: Source address, in kernel space.
 119  * @n:    Number of bytes to copy.
 120  *
 121  * Context: User context only.  This function may sleep.
 122  *
 123  * Copy data from kernel space to user space.  Caller must check
 124  * the specified block with access_ok() before calling this function.
 125  *
 126  * Returns number of bytes that could not be copied.
 127  * On success, this will be zero.
 128  */
 129 unsigned long __must_check __copy_to_user(void __user *to, const void *from,
 130                                           unsigned long n);
 131
 132 #define __copy_to_user_inatomic __copy_to_user
 133 #define __copy_from_user_inatomic __copy_from_user
 134
 135 #ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
 136
 137 #define __put_get_user_asm(to, from, size, spec)                \
 138 ({                                                              \
 139         register unsigned long __reg0 asm("0") = spec;          \
 140         int __rc;                                               \
 141                                                                 \
 142         asm volatile(                                           \
 143                 "0:     mvcos   %1,%3,%2\n"                     \
 144                 "1:     xr      %0,%0\n"                        \
 145                 "2:\n"                                          \
 146                 ".pushsection .fixup, \"ax\"\n"                 \
 147                 "3:     lhi     %0,%5\n"                        \
 148                 "       jg      2b\n"                           \
 149                 ".popsection\n"                                 \
 150                 EX_TABLE(0b,3b) EX_TABLE(1b,3b)                 \
 151                 : "=d" (__rc), "=Q" (*(to))                     \
 152                 : "d" (size), "Q" (*(from)),                    \
 153                   "d" (__reg0), "K" (-EFAULT)                   \
 154                 : "cc");                                        \
 155         __rc;                                                   \
 156 })
 157
 158 #define __put_user_fn(x, ptr, size) __put_get_user_asm(ptr, x, size, 0x810000UL)
 159 #define __get_user_fn(x, ptr, size) __put_get_user_asm(x, ptr, size, 0x81UL)
 160
 161 #else /* CONFIG_HAVE_MARCH_Z10_FEATURES */
 162
 163 static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
 164 {
 165         size = __copy_to_user(ptr, x, size);
 166         return size ? -EFAULT : 0;
 167 }
 168
 169 static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
 170 {
 171         size = __copy_from_user(x, ptr, size);
 172         return size ? -EFAULT : 0;
 173 }
 174
 175 #endif /* CONFIG_HAVE_MARCH_Z10_FEATURES */
 176
 177 /*
 178  * These are the main single-value transfer routines.  They automatically
 179  * use the right size if we just have the right pointer type.
 180  */
 181 #define __put_user(x, ptr) \
 182 ({                                                              \
 183         __typeof__(*(ptr)) __x = (x);                           \
 184         int __pu_err = -EFAULT;                                 \
 185         __chk_user_ptr(ptr);                                    \
 186         switch (sizeof (*(ptr))) {                              \
 187         case 1:                                                 \
 188         case 2:                                                 \
 189         case 4:                                                 \
 190         case 8:                                                 \
 191                 __pu_err = __put_user_fn(&__x, ptr,             \
 192                                          sizeof(*(ptr)));       \
 193                 break;                                          \
 194         default:                                                \
 195                 __put_user_bad();                               \
 196                 break;                                          \
 197          }                                                      \
 198         __pu_err;                                               \
 199 })
 200
 201 #define put_user(x, ptr)                                        \
 202 ({                                                              \
 203         might_fault();                                          \
 204         __put_user(x, ptr);                                     \
 205 })
 206
 207
 208 int __put_user_bad(void) __attribute__((noreturn));
 209
 210 #define __get_user(x, ptr)                                      \
 211 ({                                                              \
 212         int __gu_err = -EFAULT;                                 \
 213         __chk_user_ptr(ptr);                                    \
 214         switch (sizeof(*(ptr))) {                               \
 215         case 1: {                                               \
 216                 unsigned char __x;                              \
 217                 __gu_err = __get_user_fn(&__x, ptr,             \
 218                                          sizeof(*(ptr)));       \
 219                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 220                 break;                                          \
 221         };                                                      \
 222         case 2: {                                               \
 223                 unsigned short __x;                             \
 224                 __gu_err = __get_user_fn(&__x, ptr,             \
 225                                          sizeof(*(ptr)));       \
 226                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 227                 break;                                          \
 228         };                                                      \
 229         case 4: {                                               \
 230                 unsigned int __x;                               \
 231                 __gu_err = __get_user_fn(&__x, ptr,             \
 232                                          sizeof(*(ptr)));       \
 233                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 234                 break;                                          \
 235         };                                                      \
 236         case 8: {                                               \
 237                 unsigned long long __x;                         \
 238                 __gu_err = __get_user_fn(&__x, ptr,             \
 239                                          sizeof(*(ptr)));       \
 240                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 241                 break;                                          \
 242         };                                                      \
 243         default:                                                \
 244                 __get_user_bad();                               \
 245                 break;                                          \
 246         }                                                       \
 247         __gu_err;                                               \
 248 })
 249
 250 #define get_user(x, ptr)                                        \
 251 ({                                                              \
 252         might_fault();                                          \
 253         __get_user(x, ptr);                                     \
 254 })
 255
 256 int __get_user_bad(void) __attribute__((noreturn));
 257
 258 #define __put_user_unaligned __put_user
 259 #define __get_user_unaligned __get_user
 260
 261 /**
 262  * copy_to_user: - Copy a block of data into user space.
 263  * @to:   Destination address, in user space.
 264  * @from: Source address, in kernel space.
 265  * @n:    Number of bytes to copy.
 266  *
 267  * Context: User context only.  This function may sleep.
 268  *
 269  * Copy data from kernel space to user space.
 270  *
 271  * Returns number of bytes that could not be copied.
 272  * On success, this will be zero.
 273  */
 274 static inline unsigned long __must_check
 275 copy_to_user(void __user *to, const void *from, unsigned long n)
 276 {
 277         might_fault();
 278         return __copy_to_user(to, from, n);
 279 }
 280
 281 void copy_from_user_overflow(void)
 282 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
 283 __compiletime_warning("copy_from_user() buffer size is not provably correct")
 284 #endif
 285 ;
 286
 287 /**
 288  * copy_from_user: - Copy a block of data from user space.
 289  * @to:   Destination address, in kernel space.
 290  * @from: Source address, in user space.
 291  * @n:    Number of bytes to copy.
 292  *
 293  * Context: User context only.  This function may sleep.
 294  *
 295  * Copy data from user space to kernel space.
 296  *
 297  * Returns number of bytes that could not be copied.
 298  * On success, this will be zero.
 299  *
 300  * If some data could not be copied, this function will pad the copied
 301  * data to the requested size using zero bytes.
 302  */
 303 static inline unsigned long __must_check
 304 copy_from_user(void *to, const void __user *from, unsigned long n)
 305 {
 306         unsigned int sz = __compiletime_object_size(to);
 307
 308         might_fault();
 309         if (unlikely(sz != -1 && sz < n)) {
 310                 copy_from_user_overflow();
 311                 return n;
 312         }
 313         return __copy_from_user(to, from, n);
 314 }
 315
 316 unsigned long __must_check
 317 __copy_in_user(void __user *to, const void __user *from, unsigned long n);
 318
 319 static inline unsigned long __must_check
 320 copy_in_user(void __user *to, const void __user *from, unsigned long n)
 321 {
 322         might_fault();
 323         return __copy_in_user(to, from, n);
 324 }
 325
 326 /*
 327  * Copy a null terminated string from userspace.
 328  */
 329
 330 long __strncpy_from_user(char *dst, const char __user *src, long count);
 331
 332 static inline long __must_check
 333 strncpy_from_user(char *dst, const char __user *src, long count)
 334 {
 335         might_fault();
 336         return __strncpy_from_user(dst, src, count);
 337 }
 338
 339 unsigned long __must_check __strnlen_user(const char __user *src, unsigned long count);
 340
 341 static inline unsigned long strnlen_user(const char __user *src, unsigned long n)
 342 {
 343         might_fault();
 344         return __strnlen_user(src, n);
 345 }
 346
 347 /**
 348  * strlen_user: - Get the size of a string in user space.
 349  * @str: The string to measure.
 350  *
 351  * Context: User context only.  This function may sleep.
 352  *
 353  * Get the size of a NUL-terminated string in user space.
 354  *
 355  * Returns the size of the string INCLUDING the terminating NUL.
 356  * On exception, returns 0.
 357  *
 358  * If there is a limit on the length of a valid string, you may wish to
 359  * consider using strnlen_user() instead.
 360  */
 361 #define strlen_user(str) strnlen_user(str, ~0UL)
 362
 363 /*
 364  * Zero Userspace
 365  */
 366 unsigned long __must_check __clear_user(void __user *to, unsigned long size);
 367
 368 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
 369 {
 370         might_fault();
 371         return __clear_user(to, n);
 372 }
 373
 374 int copy_to_user_real(void __user *dest, void *src, unsigned long count);
 375
 376 #endif /* __S390_UACCESS_H */