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