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