arch/alpha/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ALPHA_UACCESS_H
   3 #define __ALPHA_UACCESS_H
   4
   5 /*
   6  * The fs value determines whether argument validity checking should be
   7  * performed or not.  If get_fs() == USER_DS, checking is performed, with
   8  * get_fs() == KERNEL_DS, checking is bypassed.
   9  *
  10  * Or at least it did once upon a time.  Nowadays it is a mask that
  11  * defines which bits of the address space are off limits.  This is a
  12  * wee bit faster than the above.
  13  *
  14  * For historical reasons, these macros are grossly misnamed.
  15  */
  16
  17 #define KERNEL_DS       ((mm_segment_t) { 0UL })
  18 #define USER_DS         ((mm_segment_t) { -0x40000000000UL })
  19
  20 #define get_fs()  (current_thread_info()->addr_limit)
  21 #define get_ds()  (KERNEL_DS)
  22 #define set_fs(x) (current_thread_info()->addr_limit = (x))
  23
  24 #define segment_eq(a, b)        ((a).seg == (b).seg)
  25
  26 /*
  27  * Is a address valid? This does a straightforward calculation rather
  28  * than tests.
  29  *
  30  * Address valid if:
  31  *  - "addr" doesn't have any high-bits set
  32  *  - AND "size" doesn't have any high-bits set
  33  *  - AND "addr+size-(size != 0)" doesn't have any high-bits set
  34  *  - OR we are in kernel mode.
  35  */
  36 #define __access_ok(addr, size) ({                              \
  37         unsigned long __ao_a = (addr), __ao_b = (size);         \
  38         unsigned long __ao_end = __ao_a + __ao_b - !!__ao_b;    \
  39         (get_fs().seg & (__ao_a | __ao_b | __ao_end)) == 0; })
  40
  41 #define access_ok(addr, size)                           \
  42 ({                                                      \
  43         __chk_user_ptr(addr);                           \
  44         __access_ok(((unsigned long)(addr)), (size));   \
  45 })
  46
  47 /*
  48  * These are the main single-value transfer routines.  They automatically
  49  * use the right size if we just have the right pointer type.
  50  *
  51  * As the alpha uses the same address space for kernel and user
  52  * data, we can just do these as direct assignments.  (Of course, the
  53  * exception handling means that it's no longer "just"...)
  54  *
  55  * Careful to not
  56  * (a) re-use the arguments for side effects (sizeof/typeof is ok)
  57  * (b) require any knowledge of processes at this stage
  58  */
  59 #define put_user(x, ptr) \
  60   __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  61 #define get_user(x, ptr) \
  62   __get_user_check((x), (ptr), sizeof(*(ptr)))
  63
  64 /*
  65  * The "__xxx" versions do not do address space checking, useful when
  66  * doing multiple accesses to the same area (the programmer has to do the
  67  * checks by hand with "access_ok()")
  68  */
  69 #define __put_user(x, ptr) \
  70   __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  71 #define __get_user(x, ptr) \
  72   __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  73
  74 /*
  75  * The "lda %1, 2b-1b(%0)" bits are magic to get the assembler to
  76  * encode the bits we need for resolving the exception.  See the
  77  * more extensive comments with fixup_inline_exception below for
  78  * more information.
  79  */
  80 #define EXC(label,cont,res,err)                         \
  81         ".section __ex_table,\"a\"\n"                   \
  82         "       .long "#label"-.\n"                     \
  83         "       lda "#res","#cont"-"#label"("#err")\n"  \
  84         ".previous\n"
  85
  86 extern void __get_user_unknown(void);
  87
  88 #define __get_user_nocheck(x, ptr, size)                        \
  89 ({                                                              \
  90         long __gu_err = 0;                                      \
  91         unsigned long __gu_val;                                 \
  92         __chk_user_ptr(ptr);                                    \
  93         switch (size) {                                         \
  94           case 1: __get_user_8(ptr); break;                     \
  95           case 2: __get_user_16(ptr); break;                    \
  96           case 4: __get_user_32(ptr); break;                    \
  97           case 8: __get_user_64(ptr); break;                    \
  98           default: __get_user_unknown(); break;                 \
  99         }                                                       \
 100         (x) = (__force __typeof__(*(ptr))) __gu_val;            \
 101         __gu_err;                                               \
 102 })
 103
 104 #define __get_user_check(x, ptr, size)                          \
 105 ({                                                              \
 106         long __gu_err = -EFAULT;                                \
 107         unsigned long __gu_val = 0;                             \
 108         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 109         if (__access_ok((unsigned long)__gu_addr, size)) {      \
 110                 __gu_err = 0;                                   \
 111                 switch (size) {                                 \
 112                   case 1: __get_user_8(__gu_addr); break;       \
 113                   case 2: __get_user_16(__gu_addr); break;      \
 114                   case 4: __get_user_32(__gu_addr); break;      \
 115                   case 8: __get_user_64(__gu_addr); break;      \
 116                   default: __get_user_unknown(); break;         \
 117                 }                                               \
 118         }                                                       \
 119         (x) = (__force __typeof__(*(ptr))) __gu_val;            \
 120         __gu_err;                                               \
 121 })
 122
 123 struct __large_struct { unsigned long buf[100]; };
 124 #define __m(x) (*(struct __large_struct __user *)(x))
 125
 126 #define __get_user_64(addr)                             \
 127         __asm__("1: ldq %0,%2\n"                        \
 128         "2:\n"                                          \
 129         EXC(1b,2b,%0,%1)                                \
 130                 : "=r"(__gu_val), "=r"(__gu_err)        \
 131                 : "m"(__m(addr)), "1"(__gu_err))
 132
 133 #define __get_user_32(addr)                             \
 134         __asm__("1: ldl %0,%2\n"                        \
 135         "2:\n"                                          \
 136         EXC(1b,2b,%0,%1)                                \
 137                 : "=r"(__gu_val), "=r"(__gu_err)        \
 138                 : "m"(__m(addr)), "1"(__gu_err))
 139
 140 #ifdef __alpha_bwx__
 141 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
 142
 143 #define __get_user_16(addr)                             \
 144         __asm__("1: ldwu %0,%2\n"                       \
 145         "2:\n"                                          \
 146         EXC(1b,2b,%0,%1)                                \
 147                 : "=r"(__gu_val), "=r"(__gu_err)        \
 148                 : "m"(__m(addr)), "1"(__gu_err))
 149
 150 #define __get_user_8(addr)                              \
 151         __asm__("1: ldbu %0,%2\n"                       \
 152         "2:\n"                                          \
 153         EXC(1b,2b,%0,%1)                                \
 154                 : "=r"(__gu_val), "=r"(__gu_err)        \
 155                 : "m"(__m(addr)), "1"(__gu_err))
 156 #else
 157 /* Unfortunately, we can't get an unaligned access trap for the sub-word
 158    load, so we have to do a general unaligned operation.  */
 159
 160 #define __get_user_16(addr)                                             \
 161 {                                                                       \
 162         long __gu_tmp;                                                  \
 163         __asm__("1: ldq_u %0,0(%3)\n"                                   \
 164         "2:     ldq_u %1,1(%3)\n"                                       \
 165         "       extwl %0,%3,%0\n"                                       \
 166         "       extwh %1,%3,%1\n"                                       \
 167         "       or %0,%1,%0\n"                                          \
 168         "3:\n"                                                          \
 169         EXC(1b,3b,%0,%2)                                                \
 170         EXC(2b,3b,%0,%2)                                                \
 171                 : "=&r"(__gu_val), "=&r"(__gu_tmp), "=r"(__gu_err)      \
 172                 : "r"(addr), "2"(__gu_err));                            \
 173 }
 174
 175 #define __get_user_8(addr)                                              \
 176         __asm__("1: ldq_u %0,0(%2)\n"                                   \
 177         "       extbl %0,%2,%0\n"                                       \
 178         "2:\n"                                                          \
 179         EXC(1b,2b,%0,%1)                                                \
 180                 : "=&r"(__gu_val), "=r"(__gu_err)                       \
 181                 : "r"(addr), "1"(__gu_err))
 182 #endif
 183
 184 extern void __put_user_unknown(void);
 185
 186 #define __put_user_nocheck(x, ptr, size)                        \
 187 ({                                                              \
 188         long __pu_err = 0;                                      \
 189         __chk_user_ptr(ptr);                                    \
 190         switch (size) {                                         \
 191           case 1: __put_user_8(x, ptr); break;                  \
 192           case 2: __put_user_16(x, ptr); break;                 \
 193           case 4: __put_user_32(x, ptr); break;                 \
 194           case 8: __put_user_64(x, ptr); break;                 \
 195           default: __put_user_unknown(); break;                 \
 196         }                                                       \
 197         __pu_err;                                               \
 198 })
 199
 200 #define __put_user_check(x, ptr, size)                          \
 201 ({                                                              \
 202         long __pu_err = -EFAULT;                                \
 203         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 204         if (__access_ok((unsigned long)__pu_addr, size)) {      \
 205                 __pu_err = 0;                                   \
 206                 switch (size) {                                 \
 207                   case 1: __put_user_8(x, __pu_addr); break;    \
 208                   case 2: __put_user_16(x, __pu_addr); break;   \
 209                   case 4: __put_user_32(x, __pu_addr); break;   \
 210                   case 8: __put_user_64(x, __pu_addr); break;   \
 211                   default: __put_user_unknown(); break;         \
 212                 }                                               \
 213         }                                                       \
 214         __pu_err;                                               \
 215 })
 216
 217 /*
 218  * The "__put_user_xx()" macros tell gcc they read from memory
 219  * instead of writing: this is because they do not write to
 220  * any memory gcc knows about, so there are no aliasing issues
 221  */
 222 #define __put_user_64(x, addr)                                  \
 223 __asm__ __volatile__("1: stq %r2,%1\n"                          \
 224         "2:\n"                                                  \
 225         EXC(1b,2b,$31,%0)                                       \
 226                 : "=r"(__pu_err)                                \
 227                 : "m" (__m(addr)), "rJ" (x), "0"(__pu_err))
 228
 229 #define __put_user_32(x, addr)                                  \
 230 __asm__ __volatile__("1: stl %r2,%1\n"                          \
 231         "2:\n"                                                  \
 232         EXC(1b,2b,$31,%0)                                       \
 233                 : "=r"(__pu_err)                                \
 234                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 235
 236 #ifdef __alpha_bwx__
 237 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
 238
 239 #define __put_user_16(x, addr)                                  \
 240 __asm__ __volatile__("1: stw %r2,%1\n"                          \
 241         "2:\n"                                                  \
 242         EXC(1b,2b,$31,%0)                                       \
 243                 : "=r"(__pu_err)                                \
 244                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 245
 246 #define __put_user_8(x, addr)                                   \
 247 __asm__ __volatile__("1: stb %r2,%1\n"                          \
 248         "2:\n"                                                  \
 249         EXC(1b,2b,$31,%0)                                       \
 250                 : "=r"(__pu_err)                                \
 251                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 252 #else
 253 /* Unfortunately, we can't get an unaligned access trap for the sub-word
 254    write, so we have to do a general unaligned operation.  */
 255
 256 #define __put_user_16(x, addr)                                  \
 257 {                                                               \
 258         long __pu_tmp1, __pu_tmp2, __pu_tmp3, __pu_tmp4;        \
 259         __asm__ __volatile__(                                   \
 260         "1:     ldq_u %2,1(%5)\n"                               \
 261         "2:     ldq_u %1,0(%5)\n"                               \
 262         "       inswh %6,%5,%4\n"                               \
 263         "       inswl %6,%5,%3\n"                               \
 264         "       mskwh %2,%5,%2\n"                               \
 265         "       mskwl %1,%5,%1\n"                               \
 266         "       or %2,%4,%2\n"                                  \
 267         "       or %1,%3,%1\n"                                  \
 268         "3:     stq_u %2,1(%5)\n"                               \
 269         "4:     stq_u %1,0(%5)\n"                               \
 270         "5:\n"                                                  \
 271         EXC(1b,5b,$31,%0)                                       \
 272         EXC(2b,5b,$31,%0)                                       \
 273         EXC(3b,5b,$31,%0)                                       \
 274         EXC(4b,5b,$31,%0)                                       \
 275                 : "=r"(__pu_err), "=&r"(__pu_tmp1),             \
 276                   "=&r"(__pu_tmp2), "=&r"(__pu_tmp3),           \
 277                   "=&r"(__pu_tmp4)                              \
 278                 : "r"(addr), "r"((unsigned long)(x)), "0"(__pu_err)); \
 279 }
 280
 281 #define __put_user_8(x, addr)                                   \
 282 {                                                               \
 283         long __pu_tmp1, __pu_tmp2;                              \
 284         __asm__ __volatile__(                                   \
 285         "1:     ldq_u %1,0(%4)\n"                               \
 286         "       insbl %3,%4,%2\n"                               \
 287         "       mskbl %1,%4,%1\n"                               \
 288         "       or %1,%2,%1\n"                                  \
 289         "2:     stq_u %1,0(%4)\n"                               \
 290         "3:\n"                                                  \
 291         EXC(1b,3b,$31,%0)                                       \
 292         EXC(2b,3b,$31,%0)                                       \
 293                 : "=r"(__pu_err),                               \
 294                   "=&r"(__pu_tmp1), "=&r"(__pu_tmp2)            \
 295                 : "r"((unsigned long)(x)), "r"(addr), "0"(__pu_err)); \
 296 }
 297 #endif
 298
 299
 300 /*
 301  * Complex access routines
 302  */
 303
 304 extern long __copy_user(void *to, const void *from, long len);
 305
 306 static inline unsigned long
 307 raw_copy_from_user(void *to, const void __user *from, unsigned long len)
 308 {
 309         return __copy_user(to, (__force const void *)from, len);
 310 }
 311
 312 static inline unsigned long
 313 raw_copy_to_user(void __user *to, const void *from, unsigned long len)
 314 {
 315         return __copy_user((__force void *)to, from, len);
 316 }
 317
 318 extern long __clear_user(void __user *to, long len);
 319
 320 extern inline long
 321 clear_user(void __user *to, long len)
 322 {
 323         if (__access_ok((unsigned long)to, len))
 324                 len = __clear_user(to, len);
 325         return len;
 326 }
 327
 328 #define user_addr_max() \
 329         (uaccess_kernel() ? ~0UL : TASK_SIZE)
 330
 331 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 332 extern __must_check long strnlen_user(const char __user *str, long n);
 333
 334 #include <asm/extable.h>
 335
 336 #endif /* __ALPHA_UACCESS_H */