arch/alpha/include/asm/uaccess.h

   1 #ifndef __ALPHA_UACCESS_H
   2 #define __ALPHA_UACCESS_H
   3
   4 /*
   5  * The fs value determines whether argument validity checking should be
   6  * performed or not.  If get_fs() == USER_DS, checking is performed, with
   7  * get_fs() == KERNEL_DS, checking is bypassed.
   8  *
   9  * Or at least it did once upon a time.  Nowadays it is a mask that
  10  * defines which bits of the address space are off limits.  This is a
  11  * wee bit faster than the above.
  12  *
  13  * For historical reasons, these macros are grossly misnamed.
  14  */
  15
  16 #define KERNEL_DS       ((mm_segment_t) { 0UL })
  17 #define USER_DS         ((mm_segment_t) { -0x40000000000UL })
  18
  19 #define get_fs()  (current_thread_info()->addr_limit)
  20 #define get_ds()  (KERNEL_DS)
  21 #define set_fs(x) (current_thread_info()->addr_limit = (x))
  22
  23 #define segment_eq(a, b)        ((a).seg == (b).seg)
  24
  25 /*
  26  * Is a address valid? This does a straightforward calculation rather
  27  * than tests.
  28  *
  29  * Address valid if:
  30  *  - "addr" doesn't have any high-bits set
  31  *  - AND "size" doesn't have any high-bits set
  32  *  - AND "addr+size" doesn't have any high-bits set
  33  *  - OR we are in kernel mode.
  34  */
  35 #define __access_ok(addr, size) \
  36         ((get_fs().seg & (addr | size | (addr+size))) == 0)
  37
  38 #define access_ok(type, addr, size)                     \
  39 ({                                                      \
  40         __chk_user_ptr(addr);                           \
  41         __access_ok(((unsigned long)(addr)), (size));   \
  42 })
  43
  44 /*
  45  * These are the main single-value transfer routines.  They automatically
  46  * use the right size if we just have the right pointer type.
  47  *
  48  * As the alpha uses the same address space for kernel and user
  49  * data, we can just do these as direct assignments.  (Of course, the
  50  * exception handling means that it's no longer "just"...)
  51  *
  52  * Careful to not
  53  * (a) re-use the arguments for side effects (sizeof/typeof is ok)
  54  * (b) require any knowledge of processes at this stage
  55  */
  56 #define put_user(x, ptr) \
  57   __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  58 #define get_user(x, ptr) \
  59   __get_user_check((x), (ptr), sizeof(*(ptr)))
  60
  61 /*
  62  * The "__xxx" versions do not do address space checking, useful when
  63  * doing multiple accesses to the same area (the programmer has to do the
  64  * checks by hand with "access_ok()")
  65  */
  66 #define __put_user(x, ptr) \
  67   __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  68 #define __get_user(x, ptr) \
  69   __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  70
  71 /*
  72  * The "lda %1, 2b-1b(%0)" bits are magic to get the assembler to
  73  * encode the bits we need for resolving the exception.  See the
  74  * more extensive comments with fixup_inline_exception below for
  75  * more information.
  76  */
  77 #define EXC(label,cont,res,err)                         \
  78         ".section __ex_table,\"a\"\n"                   \
  79         "       .long "#label"-.\n"                     \
  80         "       lda "#res","#cont"-"#label"("#err")\n"  \
  81         ".previous\n"
  82
  83 extern void __get_user_unknown(void);
  84
  85 #define __get_user_nocheck(x, ptr, size)                        \
  86 ({                                                              \
  87         long __gu_err = 0;                                      \
  88         unsigned long __gu_val;                                 \
  89         __chk_user_ptr(ptr);                                    \
  90         switch (size) {                                         \
  91           case 1: __get_user_8(ptr); break;                     \
  92           case 2: __get_user_16(ptr); break;                    \
  93           case 4: __get_user_32(ptr); break;                    \
  94           case 8: __get_user_64(ptr); break;                    \
  95           default: __get_user_unknown(); break;                 \
  96         }                                                       \
  97         (x) = (__force __typeof__(*(ptr))) __gu_val;            \
  98         __gu_err;                                               \
  99 })
 100
 101 #define __get_user_check(x, ptr, size)                          \
 102 ({                                                              \
 103         long __gu_err = -EFAULT;                                \
 104         unsigned long __gu_val = 0;                             \
 105         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 106         if (__access_ok((unsigned long)__gu_addr, size)) {      \
 107                 __gu_err = 0;                                   \
 108                 switch (size) {                                 \
 109                   case 1: __get_user_8(__gu_addr); break;       \
 110                   case 2: __get_user_16(__gu_addr); break;      \
 111                   case 4: __get_user_32(__gu_addr); break;      \
 112                   case 8: __get_user_64(__gu_addr); break;      \
 113                   default: __get_user_unknown(); break;         \
 114                 }                                               \
 115         }                                                       \
 116         (x) = (__force __typeof__(*(ptr))) __gu_val;            \
 117         __gu_err;                                               \
 118 })
 119
 120 struct __large_struct { unsigned long buf[100]; };
 121 #define __m(x) (*(struct __large_struct __user *)(x))
 122
 123 #define __get_user_64(addr)                             \
 124         __asm__("1: ldq %0,%2\n"                        \
 125         "2:\n"                                          \
 126         EXC(1b,2b,%0,%1)                                \
 127                 : "=r"(__gu_val), "=r"(__gu_err)        \
 128                 : "m"(__m(addr)), "1"(__gu_err))
 129
 130 #define __get_user_32(addr)                             \
 131         __asm__("1: ldl %0,%2\n"                        \
 132         "2:\n"                                          \
 133         EXC(1b,2b,%0,%1)                                \
 134                 : "=r"(__gu_val), "=r"(__gu_err)        \
 135                 : "m"(__m(addr)), "1"(__gu_err))
 136
 137 #ifdef __alpha_bwx__
 138 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
 139
 140 #define __get_user_16(addr)                             \
 141         __asm__("1: ldwu %0,%2\n"                       \
 142         "2:\n"                                          \
 143         EXC(1b,2b,%0,%1)                                \
 144                 : "=r"(__gu_val), "=r"(__gu_err)        \
 145                 : "m"(__m(addr)), "1"(__gu_err))
 146
 147 #define __get_user_8(addr)                              \
 148         __asm__("1: ldbu %0,%2\n"                       \
 149         "2:\n"                                          \
 150         EXC(1b,2b,%0,%1)                                \
 151                 : "=r"(__gu_val), "=r"(__gu_err)        \
 152                 : "m"(__m(addr)), "1"(__gu_err))
 153 #else
 154 /* Unfortunately, we can't get an unaligned access trap for the sub-word
 155    load, so we have to do a general unaligned operation.  */
 156
 157 #define __get_user_16(addr)                                             \
 158 {                                                                       \
 159         long __gu_tmp;                                                  \
 160         __asm__("1: ldq_u %0,0(%3)\n"                                   \
 161         "2:     ldq_u %1,1(%3)\n"                                       \
 162         "       extwl %0,%3,%0\n"                                       \
 163         "       extwh %1,%3,%1\n"                                       \
 164         "       or %0,%1,%0\n"                                          \
 165         "3:\n"                                                          \
 166         EXC(1b,3b,%0,%2)                                                \
 167         EXC(2b,3b,%0,%2)                                                \
 168                 : "=&r"(__gu_val), "=&r"(__gu_tmp), "=r"(__gu_err)      \
 169                 : "r"(addr), "2"(__gu_err));                            \
 170 }
 171
 172 #define __get_user_8(addr)                                              \
 173         __asm__("1: ldq_u %0,0(%2)\n"                                   \
 174         "       extbl %0,%2,%0\n"                                       \
 175         "2:\n"                                                          \
 176         EXC(1b,2b,%0,%1)                                                \
 177                 : "=&r"(__gu_val), "=r"(__gu_err)                       \
 178                 : "r"(addr), "1"(__gu_err))
 179 #endif
 180
 181 extern void __put_user_unknown(void);
 182
 183 #define __put_user_nocheck(x, ptr, size)                        \
 184 ({                                                              \
 185         long __pu_err = 0;                                      \
 186         __chk_user_ptr(ptr);                                    \
 187         switch (size) {                                         \
 188           case 1: __put_user_8(x, ptr); break;                  \
 189           case 2: __put_user_16(x, ptr); break;                 \
 190           case 4: __put_user_32(x, ptr); break;                 \
 191           case 8: __put_user_64(x, ptr); break;                 \
 192           default: __put_user_unknown(); break;                 \
 193         }                                                       \
 194         __pu_err;                                               \
 195 })
 196
 197 #define __put_user_check(x, ptr, size)                          \
 198 ({                                                              \
 199         long __pu_err = -EFAULT;                                \
 200         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 201         if (__access_ok((unsigned long)__pu_addr, size)) {      \
 202                 __pu_err = 0;                                   \
 203                 switch (size) {                                 \
 204                   case 1: __put_user_8(x, __pu_addr); break;    \
 205                   case 2: __put_user_16(x, __pu_addr); break;   \
 206                   case 4: __put_user_32(x, __pu_addr); break;   \
 207                   case 8: __put_user_64(x, __pu_addr); break;   \
 208                   default: __put_user_unknown(); break;         \
 209                 }                                               \
 210         }                                                       \
 211         __pu_err;                                               \
 212 })
 213
 214 /*
 215  * The "__put_user_xx()" macros tell gcc they read from memory
 216  * instead of writing: this is because they do not write to
 217  * any memory gcc knows about, so there are no aliasing issues
 218  */
 219 #define __put_user_64(x, addr)                                  \
 220 __asm__ __volatile__("1: stq %r2,%1\n"                          \
 221         "2:\n"                                                  \
 222         EXC(1b,2b,$31,%0)                                       \
 223                 : "=r"(__pu_err)                                \
 224                 : "m" (__m(addr)), "rJ" (x), "0"(__pu_err))
 225
 226 #define __put_user_32(x, addr)                                  \
 227 __asm__ __volatile__("1: stl %r2,%1\n"                          \
 228         "2:\n"                                                  \
 229         EXC(1b,2b,$31,%0)                                       \
 230                 : "=r"(__pu_err)                                \
 231                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 232
 233 #ifdef __alpha_bwx__
 234 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
 235
 236 #define __put_user_16(x, addr)                                  \
 237 __asm__ __volatile__("1: stw %r2,%1\n"                          \
 238         "2:\n"                                                  \
 239         EXC(1b,2b,$31,%0)                                       \
 240                 : "=r"(__pu_err)                                \
 241                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 242
 243 #define __put_user_8(x, addr)                                   \
 244 __asm__ __volatile__("1: stb %r2,%1\n"                          \
 245         "2:\n"                                                  \
 246         EXC(1b,2b,$31,%0)                                       \
 247                 : "=r"(__pu_err)                                \
 248                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 249 #else
 250 /* Unfortunately, we can't get an unaligned access trap for the sub-word
 251    write, so we have to do a general unaligned operation.  */
 252
 253 #define __put_user_16(x, addr)                                  \
 254 {                                                               \
 255         long __pu_tmp1, __pu_tmp2, __pu_tmp3, __pu_tmp4;        \
 256         __asm__ __volatile__(                                   \
 257         "1:     ldq_u %2,1(%5)\n"                               \
 258         "2:     ldq_u %1,0(%5)\n"                               \
 259         "       inswh %6,%5,%4\n"                               \
 260         "       inswl %6,%5,%3\n"                               \
 261         "       mskwh %2,%5,%2\n"                               \
 262         "       mskwl %1,%5,%1\n"                               \
 263         "       or %2,%4,%2\n"                                  \
 264         "       or %1,%3,%1\n"                                  \
 265         "3:     stq_u %2,1(%5)\n"                               \
 266         "4:     stq_u %1,0(%5)\n"                               \
 267         "5:\n"                                                  \
 268         EXC(1b,5b,$31,%0)                                       \
 269         EXC(2b,5b,$31,%0)                                       \
 270         EXC(3b,5b,$31,%0)                                       \
 271         EXC(4b,5b,$31,%0)                                       \
 272                 : "=r"(__pu_err), "=&r"(__pu_tmp1),             \
 273                   "=&r"(__pu_tmp2), "=&r"(__pu_tmp3),           \
 274                   "=&r"(__pu_tmp4)                              \
 275                 : "r"(addr), "r"((unsigned long)(x)), "0"(__pu_err)); \
 276 }
 277
 278 #define __put_user_8(x, addr)                                   \
 279 {                                                               \
 280         long __pu_tmp1, __pu_tmp2;                              \
 281         __asm__ __volatile__(                                   \
 282         "1:     ldq_u %1,0(%4)\n"                               \
 283         "       insbl %3,%4,%2\n"                               \
 284         "       mskbl %1,%4,%1\n"                               \
 285         "       or %1,%2,%1\n"                                  \
 286         "2:     stq_u %1,0(%4)\n"                               \
 287         "3:\n"                                                  \
 288         EXC(1b,3b,$31,%0)                                       \
 289         EXC(2b,3b,$31,%0)                                       \
 290                 : "=r"(__pu_err),                               \
 291                   "=&r"(__pu_tmp1), "=&r"(__pu_tmp2)            \
 292                 : "r"((unsigned long)(x)), "r"(addr), "0"(__pu_err)); \
 293 }
 294 #endif
 295
 296
 297 /*
 298  * Complex access routines
 299  */
 300
 301 extern long __copy_user(void *to, const void *from, long len);
 302
 303 static inline unsigned long
 304 raw_copy_from_user(void *to, const void __user *from, unsigned long len)
 305 {
 306         return __copy_user(to, (__force const void *)from, len);
 307 }
 308
 309 static inline unsigned long
 310 raw_copy_to_user(void __user *to, const void *from, unsigned long len)
 311 {
 312         return __copy_user((__force void *)to, from, len);
 313 }
 314
 315 extern long __clear_user(void __user *to, long len);
 316
 317 extern inline long
 318 clear_user(void __user *to, long len)
 319 {
 320         if (__access_ok((unsigned long)to, len))
 321                 len = __clear_user(to, len);
 322         return len;
 323 }
 324
 325 #define user_addr_max() \
 326         (uaccess_kernel() ? ~0UL : TASK_SIZE)
 327
 328 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 329 extern __must_check long strnlen_user(const char __user *str, long n);
 330
 331 #include <asm/extable.h>
 332
 333 #endif /* __ALPHA_UACCESS_H */