asm-ppc/uaccess.h

   1 #ifdef __KERNEL__
   2 #ifndef _PPC_UACCESS_H
   3 #define _PPC_UACCESS_H
   4
   5 #ifndef __ASSEMBLY__
   6 #include <linux/sched.h>
   7 #include <linux/errno.h>
   8 #include <asm/processor.h>
   9
  10 #define VERIFY_READ     0
  11 #define VERIFY_WRITE    1
  12
  13 /*
  14  * The fs value determines whether argument validity checking should be
  15  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  16  * get_fs() == KERNEL_DS, checking is bypassed.
  17  *
  18  * For historical reasons, these macros are grossly misnamed.
  19  */
  20
  21 #define KERNEL_DS       ((mm_segment_t) { 0 })
  22 #define USER_DS         ((mm_segment_t) { 1 })
  23
  24 #define get_ds()        (KERNEL_DS)
  25 #define get_fs()        (current->thread.fs)
  26 #define set_fs(val)     (current->thread.fs = (val))
  27
  28 #define segment_eq(a,b) ((a).seg == (b).seg)
  29
  30 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
  31 #define __user_ok(addr,size) (((size) <= TASK_SIZE)&&((addr) <= TASK_SIZE-(size)))
  32 #define __access_ok(addr,size) (__kernel_ok || __user_ok((addr),(size)))
  33 #define access_ok(type,addr,size) __access_ok((unsigned long)(addr),(size))
  34
  35 extern inline int verify_area(int type, const void * addr, unsigned long size)
  36 {
  37         return access_ok(type,addr,size) ? 0 : -EFAULT;
  38 }
  39
  40
  41 /*
  42  * The exception table consists of pairs of addresses: the first is the
  43  * address of an instruction that is allowed to fault, and the second is
  44  * the address at which the program should continue.  No registers are
  45  * modified, so it is entirely up to the continuation code to figure out
  46  * what to do.
  47  *
  48  * All the routines below use bits of fixup code that are out of line
  49  * with the main instruction path.  This means when everything is well,
  50  * we don't even have to jump over them.  Further, they do not intrude
  51  * on our cache or tlb entries.
  52  */
  53
  54 struct exception_table_entry
  55 {
  56         unsigned long insn, fixup;
  57 };
  58
  59 /* Returns 0 if exception not found and fixup otherwise.  */
  60 extern unsigned long search_exception_table(unsigned long);
  61 extern void sort_exception_table(void);
  62
  63 /*
  64  * These are the main single-value transfer routines.  They automatically
  65  * use the right size if we just have the right pointer type.
  66  *
  67  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  68  * and yet we don't want to do any pointers, because that is too much
  69  * of a performance impact. Thus we have a few rather ugly macros here,
  70  * and hide all the uglyness from the user.
  71  *
  72  * The "__xxx" versions of the user access functions are versions that
  73  * do not verify the address space, that must have been done previously
  74  * with a separate "access_ok()" call (this is used when we do multiple
  75  * accesses to the same area of user memory).
  76  *
  77  * As we use the same address space for kernel and user data on the
  78  * PowerPC, we can just do these as direct assignments.  (Of course, the
  79  * exception handling means that it's no longer "just"...)
  80  *
  81  * The "user64" versions of the user access functions are versions that
  82  * allow access of 64-bit data. The "get_user" functions do not
  83  * properly handle 64-bit data because the value gets down cast to a long.
  84  * The "put_user" functions already handle 64-bit data properly but we add
  85  * "user64" versions for completeness
  86  */
  87 #define get_user(x,ptr) \
  88   __get_user_check((x),(ptr),sizeof(*(ptr)))
  89 #define get_user64(x,ptr) \
  90   __get_user64_check((x),(ptr),sizeof(*(ptr)))
  91 #define put_user(x,ptr) \
  92   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
  93 #define put_user64(x,ptr) put_user(x,ptr)
  94
  95 #define __get_user(x,ptr) \
  96   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
  97 #define __get_user64(x,ptr) \
  98   __get_user64_nocheck((x),(ptr),sizeof(*(ptr)))
  99 #define __put_user(x,ptr) \
 100   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 101 #define __put_user64(x,ptr) __put_user(x,ptr)
 102
 103 extern long __put_user_bad(void);
 104
 105 #define __put_user_nocheck(x,ptr,size)                  \
 106 ({                                                      \
 107         long __pu_err;                                  \
 108         __put_user_size((x),(ptr),(size),__pu_err);     \
 109         __pu_err;                                       \
 110 })
 111
 112 #define __put_user_check(x,ptr,size)                            \
 113 ({                                                              \
 114         long __pu_err = -EFAULT;                                \
 115         __typeof__(*(ptr)) *__pu_addr = (ptr);                  \
 116         if (access_ok(VERIFY_WRITE,__pu_addr,size))             \
 117                 __put_user_size((x),__pu_addr,(size),__pu_err); \
 118         __pu_err;                                               \
 119 })
 120
 121 #define __put_user_size(x,ptr,size,retval)                      \
 122 do {                                                            \
 123         retval = 0;                                             \
 124         switch (size) {                                         \
 125           case 1: __put_user_asm(x,ptr,retval,"stb"); break;    \
 126           case 2: __put_user_asm(x,ptr,retval,"sth"); break;    \
 127           case 4: __put_user_asm(x,ptr,retval,"stw"); break;    \
 128           case 8: __put_user_asm2(x,ptr,retval); break;         \
 129           default: __put_user_bad();                            \
 130         }                                                       \
 131 } while (0)
 132
 133 struct __large_struct { unsigned long buf[100]; };
 134 #define __m(x) (*(struct __large_struct *)(x))
 135
 136 /*
 137  * We don't tell gcc that we are accessing memory, but this is OK
 138  * because we do not write to any memory gcc knows about, so there
 139  * are no aliasing issues.
 140  */
 141 #define __put_user_asm(x, addr, err, op)                        \
 142         __asm__ __volatile__(                                   \
 143                 "1:     "op" %1,0(%2)\n"                        \
 144                 "2:\n"                                          \
 145                 ".section .fixup,\"ax\"\n"                      \
 146                 "3:     li %0,%3\n"                             \
 147                 "       b 2b\n"                                 \
 148                 ".previous\n"                                   \
 149                 ".section __ex_table,\"a\"\n"                   \
 150                 "       .align 2\n"                             \
 151                 "       .long 1b,3b\n"                          \
 152                 ".previous"                                     \
 153                 : "=r"(err)                                     \
 154                 : "r"(x), "b"(addr), "i"(-EFAULT), "0"(err))
 155
 156 #define __put_user_asm2(x, addr, err)                           \
 157         __asm__ __volatile__(                                   \
 158                 "1:     stw %1,0(%2)\n"                         \
 159                 "2:     stw %1+1,4(%2)\n"                               \
 160                 "3:\n"                                          \
 161                 ".section .fixup,\"ax\"\n"                      \
 162                 "4:     li %0,%3\n"                             \
 163                 "       b 3b\n"                                 \
 164                 ".previous\n"                                   \
 165                 ".section __ex_table,\"a\"\n"                   \
 166                 "       .align 2\n"                             \
 167                 "       .long 1b,4b\n"                          \
 168                 "       .long 2b,4b\n"                          \
 169                 ".previous"                                     \
 170                 : "=r"(err)                                     \
 171                 : "r"(x), "b"(addr), "i"(-EFAULT), "0"(err))
 172
 173 #define __get_user_nocheck(x,ptr,size)                          \
 174 ({                                                              \
 175         long __gu_err, __gu_val;                                \
 176         __get_user_size(__gu_val,(ptr),(size),__gu_err);        \
 177         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 178         __gu_err;                                               \
 179 })
 180
 181 #define __get_user64_nocheck(x,ptr,size)                        \
 182 ({                                                              \
 183         long __gu_err;                                          \
 184         long long __gu_val;                                     \
 185         __get_user_size64(__gu_val,(ptr),(size),__gu_err);      \
 186         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 187         __gu_err;                                               \
 188 })
 189
 190 #define __get_user_check(x,ptr,size)                                    \
 191 ({                                                                      \
 192         long __gu_err = -EFAULT, __gu_val = 0;                          \
 193         const __typeof__(*(ptr)) *__gu_addr = (ptr);                    \
 194         if (access_ok(VERIFY_READ,__gu_addr,size))                      \
 195                 __get_user_size(__gu_val,__gu_addr,(size),__gu_err);    \
 196         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 197         __gu_err;                                                       \
 198 })
 199
 200 #define __get_user64_check(x,ptr,size)                                  \
 201 ({                                                                      \
 202         long __gu_err = -EFAULT;                                        \
 203         long long __gu_val = 0;                                         \
 204         const __typeof__(*(ptr)) *__gu_addr = (ptr);                    \
 205         if (access_ok(VERIFY_READ,__gu_addr,size))                      \
 206                 __get_user_size64(__gu_val,__gu_addr,(size),__gu_err);  \
 207         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 208         __gu_err;                                                       \
 209 })
 210
 211 extern long __get_user_bad(void);
 212
 213 #define __get_user_size(x,ptr,size,retval)                      \
 214 do {                                                            \
 215         retval = 0;                                             \
 216         switch (size) {                                         \
 217           case 1: __get_user_asm(x,ptr,retval,"lbz"); break;    \
 218           case 2: __get_user_asm(x,ptr,retval,"lhz"); break;    \
 219           case 4: __get_user_asm(x,ptr,retval,"lwz"); break;    \
 220           default: (x) = __get_user_bad();                      \
 221         }                                                       \
 222 } while (0)
 223
 224 #define __get_user_size64(x,ptr,size,retval)                    \
 225 do {                                                            \
 226         retval = 0;                                             \
 227         switch (size) {                                         \
 228           case 1: __get_user_asm(x,ptr,retval,"lbz"); break;    \
 229           case 2: __get_user_asm(x,ptr,retval,"lhz"); break;    \
 230           case 4: __get_user_asm(x,ptr,retval,"lwz"); break;    \
 231           case 8: __get_user_asm2(x, ptr, retval); break;       \
 232           default: (x) = __get_user_bad();                      \
 233         }                                                       \
 234 } while (0)
 235
 236 #define __get_user_asm(x, addr, err, op)                \
 237         __asm__ __volatile__(                           \
 238                 "1:     "op" %1,0(%2)\n"                \
 239                 "2:\n"                                  \
 240                 ".section .fixup,\"ax\"\n"              \
 241                 "3:     li %0,%3\n"                     \
 242                 "       li %1,0\n"                      \
 243                 "       b 2b\n"                         \
 244                 ".previous\n"                           \
 245                 ".section __ex_table,\"a\"\n"           \
 246                 "       .align 2\n"                     \
 247                 "       .long 1b,3b\n"                  \
 248                 ".previous"                             \
 249                 : "=r"(err), "=r"(x)                    \
 250                 : "b"(addr), "i"(-EFAULT), "0"(err))
 251
 252 #define __get_user_asm2(x, addr, err)                   \
 253         __asm__ __volatile__(                           \
 254                 "1:     lwz %1,0(%2)\n"                 \
 255                 "2:     lwz %1+1,4(%2)\n"               \
 256                 "3:\n"                                  \
 257                 ".section .fixup,\"ax\"\n"              \
 258                 "4:     li %0,%3\n"                     \
 259                 "       li %1,0\n"                      \
 260                 "       li %1+1,0\n"                    \
 261                 "       b 3b\n"                         \
 262                 ".previous\n"                           \
 263                 ".section __ex_table,\"a\"\n"           \
 264                 "       .align 2\n"                     \
 265                 "       .long 1b,4b\n"                  \
 266                 "       .long 2b,4b\n"                  \
 267                 ".previous"                             \
 268                 : "=r"(err), "=&r"(x)                   \
 269                 : "b"(addr), "i"(-EFAULT), "0"(err))
 270
 271 /* more complex routines */
 272
 273 extern int __copy_tofrom_user(void *to, const void *from, unsigned long size);
 274
 275 extern inline unsigned long
 276 copy_from_user(void *to, const void *from, unsigned long n)
 277 {
 278         unsigned long over;
 279
 280         if (access_ok(VERIFY_READ, from, n))
 281                 return __copy_tofrom_user(to, from, n);
 282         if ((unsigned long)from < TASK_SIZE) {
 283                 over = (unsigned long)from + n - TASK_SIZE;
 284                 return __copy_tofrom_user(to, from, n - over) + over;
 285         }
 286         return n;
 287 }
 288
 289 extern inline unsigned long
 290 copy_to_user(void *to, const void *from, unsigned long n)
 291 {
 292         unsigned long over;
 293
 294         if (access_ok(VERIFY_WRITE, to, n))
 295                 return __copy_tofrom_user(to, from, n);
 296         if ((unsigned long)to < TASK_SIZE) {
 297                 over = (unsigned long)to + n - TASK_SIZE;
 298                 return __copy_tofrom_user(to, from, n - over) + over;
 299         }
 300         return n;
 301 }
 302
 303 #define __copy_from_user(to, from, size) \
 304         __copy_tofrom_user((to), (from), (size))
 305 #define __copy_to_user(to, from, size) \
 306         __copy_tofrom_user((to), (from), (size))
 307
 308 extern unsigned long __clear_user(void *addr, unsigned long size);
 309
 310 extern inline unsigned long
 311 clear_user(void *addr, unsigned long size)
 312 {
 313         if (access_ok(VERIFY_WRITE, addr, size))
 314                 return __clear_user(addr, size);
 315         if ((unsigned long)addr < TASK_SIZE) {
 316                 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
 317                 return __clear_user(addr, size - over) + over;
 318         }
 319         return size;
 320 }
 321
 322 extern int __strncpy_from_user(char *dst, const char *src, long count);
 323
 324 extern inline long
 325 strncpy_from_user(char *dst, const char *src, long count)
 326 {
 327         if (access_ok(VERIFY_READ, src, 1))
 328                 return __strncpy_from_user(dst, src, count);
 329         return -EFAULT;
 330 }
 331
 332 /*
 333  * Return the size of a string (including the ending 0)
 334  *
 335  * Return 0 for error
 336  */
 337
 338 extern int __strnlen_user(const char *str, long len, unsigned long top);
 339
 340 /*
 341  * Returns the length of the string at str (including the null byte),
 342  * or 0 if we hit a page we can't access,
 343  * or something > len if we didn't find a null byte.
 344  *
 345  * The `top' parameter to __strnlen_user is to make sure that
 346  * we can never overflow from the user area into kernel space.
 347  */
 348 extern __inline__ int strnlen_user(const char *str, long len)
 349 {
 350         unsigned long top = __kernel_ok? ~0UL: TASK_SIZE - 1;
 351
 352         if ((unsigned long)str > top)
 353                 return 0;
 354         return __strnlen_user(str, len, top);
 355 }
 356
 357 #define strlen_user(str)        strnlen_user((str), 0x7ffffffe)
 358
 359 #endif  /* __ASSEMBLY__ */
 360
 361 #endif  /* _PPC_UACCESS_H */
 362 #endif /* __KERNEL__ */