arch/powerpc/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ARCH_POWERPC_UACCESS_H
   3 #define _ARCH_POWERPC_UACCESS_H
   4
   5 #include <asm/ppc_asm.h>
   6 #include <asm/processor.h>
   7 #include <asm/page.h>
   8 #include <asm/extable.h>
   9
  10 /*
  11  * The fs value determines whether argument validity checking should be
  12  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  13  * get_fs() == KERNEL_DS, checking is bypassed.
  14  *
  15  * For historical reasons, these macros are grossly misnamed.
  16  *
  17  * The fs/ds values are now the highest legal address in the "segment".
  18  * This simplifies the checking in the routines below.
  19  */
  20
  21 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  22
  23 #define KERNEL_DS       MAKE_MM_SEG(~0UL)
  24 #ifdef __powerpc64__
  25 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
  26 #define USER_DS         MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
  27 #else
  28 #define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
  29 #endif
  30
  31 #define get_ds()        (KERNEL_DS)
  32 #define get_fs()        (current->thread.addr_limit)
  33
  34 static inline void set_fs(mm_segment_t fs)
  35 {
  36         current->thread.addr_limit = fs;
  37         /* On user-mode return check addr_limit (fs) is correct */
  38         set_thread_flag(TIF_FSCHECK);
  39 }
  40
  41 #define segment_eq(a, b)        ((a).seg == (b).seg)
  42
  43 #define user_addr_max() (get_fs().seg)
  44
  45 #ifdef __powerpc64__
  46 /*
  47  * This check is sufficient because there is a large enough
  48  * gap between user addresses and the kernel addresses
  49  */
  50 #define __access_ok(addr, size, segment)        \
  51         (((addr) <= (segment).seg) && ((size) <= (segment).seg))
  52
  53 #else
  54
  55 static inline int __access_ok(unsigned long addr, unsigned long size,
  56                         mm_segment_t seg)
  57 {
  58         if (addr > seg.seg)
  59                 return 0;
  60         return (size == 0 || size - 1 <= seg.seg - addr);
  61 }
  62
  63 #endif
  64
  65 #define access_ok(addr, size)           \
  66         (__chk_user_ptr(addr), (void)(type),            \
  67          __access_ok((__force unsigned long)(addr), (size), get_fs()))
  68
  69 /*
  70  * These are the main single-value transfer routines.  They automatically
  71  * use the right size if we just have the right pointer type.
  72  *
  73  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  74  * and yet we don't want to do any pointers, because that is too much
  75  * of a performance impact. Thus we have a few rather ugly macros here,
  76  * and hide all the ugliness from the user.
  77  *
  78  * The "__xxx" versions of the user access functions are versions that
  79  * do not verify the address space, that must have been done previously
  80  * with a separate "access_ok()" call (this is used when we do multiple
  81  * accesses to the same area of user memory).
  82  *
  83  * As we use the same address space for kernel and user data on the
  84  * PowerPC, we can just do these as direct assignments.  (Of course, the
  85  * exception handling means that it's no longer "just"...)
  86  *
  87  */
  88 #define get_user(x, ptr) \
  89         __get_user_check((x), (ptr), sizeof(*(ptr)))
  90 #define put_user(x, ptr) \
  91         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  92
  93 #define __get_user(x, ptr) \
  94         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  95 #define __put_user(x, ptr) \
  96         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  97
  98 #define __get_user_inatomic(x, ptr) \
  99         __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
 100 #define __put_user_inatomic(x, ptr) \
 101         __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 102
 103 extern long __put_user_bad(void);
 104
 105 /*
 106  * We don't tell gcc that we are accessing memory, but this is OK
 107  * because we do not write to any memory gcc knows about, so there
 108  * are no aliasing issues.
 109  */
 110 #define __put_user_asm(x, addr, err, op)                        \
 111         __asm__ __volatile__(                                   \
 112                 "1:     " op " %1,0(%2) # put_user\n"           \
 113                 "2:\n"                                          \
 114                 ".section .fixup,\"ax\"\n"                      \
 115                 "3:     li %0,%3\n"                             \
 116                 "       b 2b\n"                                 \
 117                 ".previous\n"                                   \
 118                 EX_TABLE(1b, 3b)                                \
 119                 : "=r" (err)                                    \
 120                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 121
 122 #ifdef __powerpc64__
 123 #define __put_user_asm2(x, ptr, retval)                         \
 124           __put_user_asm(x, ptr, retval, "std")
 125 #else /* __powerpc64__ */
 126 #define __put_user_asm2(x, addr, err)                           \
 127         __asm__ __volatile__(                                   \
 128                 "1:     stw %1,0(%2)\n"                         \
 129                 "2:     stw %1+1,4(%2)\n"                       \
 130                 "3:\n"                                          \
 131                 ".section .fixup,\"ax\"\n"                      \
 132                 "4:     li %0,%3\n"                             \
 133                 "       b 3b\n"                                 \
 134                 ".previous\n"                                   \
 135                 EX_TABLE(1b, 4b)                                \
 136                 EX_TABLE(2b, 4b)                                \
 137                 : "=r" (err)                                    \
 138                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 139 #endif /* __powerpc64__ */
 140
 141 #define __put_user_size(x, ptr, size, retval)                   \
 142 do {                                                            \
 143         retval = 0;                                             \
 144         switch (size) {                                         \
 145           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 146           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 147           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 148           case 8: __put_user_asm2(x, ptr, retval); break;       \
 149           default: __put_user_bad();                            \
 150         }                                                       \
 151 } while (0)
 152
 153 #define __put_user_nocheck(x, ptr, size)                        \
 154 ({                                                              \
 155         long __pu_err;                                          \
 156         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 157         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 158                 might_fault();                                  \
 159         __chk_user_ptr(ptr);                                    \
 160         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 161         __pu_err;                                               \
 162 })
 163
 164 #define __put_user_check(x, ptr, size)                                  \
 165 ({                                                                      \
 166         long __pu_err = -EFAULT;                                        \
 167         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 168         might_fault();                                                  \
 169         if (access_ok(__pu_addr, size))                 \
 170                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 171         __pu_err;                                                       \
 172 })
 173
 174 #define __put_user_nosleep(x, ptr, size)                        \
 175 ({                                                              \
 176         long __pu_err;                                          \
 177         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 178         __chk_user_ptr(ptr);                                    \
 179         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 180         __pu_err;                                               \
 181 })
 182
 183
 184 extern long __get_user_bad(void);
 185
 186 /*
 187  * This does an atomic 128 byte aligned load from userspace.
 188  * Upto caller to do enable_kernel_vmx() before calling!
 189  */
 190 #define __get_user_atomic_128_aligned(kaddr, uaddr, err)                \
 191         __asm__ __volatile__(                           \
 192                 "1:     lvx  0,0,%1     # get user\n"   \
 193                 "       stvx 0,0,%2     # put kernel\n" \
 194                 "2:\n"                                  \
 195                 ".section .fixup,\"ax\"\n"              \
 196                 "3:     li %0,%3\n"                     \
 197                 "       b 2b\n"                         \
 198                 ".previous\n"                           \
 199                 EX_TABLE(1b, 3b)                        \
 200                 : "=r" (err)                    \
 201                 : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err))
 202
 203 #define __get_user_asm(x, addr, err, op)                \
 204         __asm__ __volatile__(                           \
 205                 "1:     "op" %1,0(%2)   # get_user\n"   \
 206                 "2:\n"                                  \
 207                 ".section .fixup,\"ax\"\n"              \
 208                 "3:     li %0,%3\n"                     \
 209                 "       li %1,0\n"                      \
 210                 "       b 2b\n"                         \
 211                 ".previous\n"                           \
 212                 EX_TABLE(1b, 3b)                        \
 213                 : "=r" (err), "=r" (x)                  \
 214                 : "b" (addr), "i" (-EFAULT), "0" (err))
 215
 216 #ifdef __powerpc64__
 217 #define __get_user_asm2(x, addr, err)                   \
 218         __get_user_asm(x, addr, err, "ld")
 219 #else /* __powerpc64__ */
 220 #define __get_user_asm2(x, addr, err)                   \
 221         __asm__ __volatile__(                           \
 222                 "1:     lwz %1,0(%2)\n"                 \
 223                 "2:     lwz %1+1,4(%2)\n"               \
 224                 "3:\n"                                  \
 225                 ".section .fixup,\"ax\"\n"              \
 226                 "4:     li %0,%3\n"                     \
 227                 "       li %1,0\n"                      \
 228                 "       li %1+1,0\n"                    \
 229                 "       b 3b\n"                         \
 230                 ".previous\n"                           \
 231                 EX_TABLE(1b, 4b)                        \
 232                 EX_TABLE(2b, 4b)                        \
 233                 : "=r" (err), "=&r" (x)                 \
 234                 : "b" (addr), "i" (-EFAULT), "0" (err))
 235 #endif /* __powerpc64__ */
 236
 237 #define __get_user_size(x, ptr, size, retval)                   \
 238 do {                                                            \
 239         retval = 0;                                             \
 240         __chk_user_ptr(ptr);                                    \
 241         if (size > sizeof(x))                                   \
 242                 (x) = __get_user_bad();                         \
 243         switch (size) {                                         \
 244         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 245         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 246         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 247         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 248         default: (x) = __get_user_bad();                        \
 249         }                                                       \
 250 } while (0)
 251
 252 /*
 253  * This is a type: either unsigned long, if the argument fits into
 254  * that type, or otherwise unsigned long long.
 255  */
 256 #define __long_type(x) \
 257         __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 258
 259 #define __get_user_nocheck(x, ptr, size)                        \
 260 ({                                                              \
 261         long __gu_err;                                          \
 262         __long_type(*(ptr)) __gu_val;                           \
 263         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
 264         __chk_user_ptr(ptr);                                    \
 265         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 266                 might_fault();                                  \
 267         barrier_nospec();                                       \
 268         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 269         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 270         __gu_err;                                               \
 271 })
 272
 273 #define __get_user_check(x, ptr, size)                                  \
 274 ({                                                                      \
 275         long __gu_err = -EFAULT;                                        \
 276         __long_type(*(ptr)) __gu_val = 0;                               \
 277         __typeof__(*(ptr)) __user *__gu_addr = (ptr);           \
 278         might_fault();                                                  \
 279         if (access_ok(__gu_addr, (size))) {             \
 280                 barrier_nospec();                                       \
 281                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 282         }                                                               \
 283         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 284         __gu_err;                                                       \
 285 })
 286
 287 #define __get_user_nosleep(x, ptr, size)                        \
 288 ({                                                              \
 289         long __gu_err;                                          \
 290         __long_type(*(ptr)) __gu_val;                           \
 291         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
 292         __chk_user_ptr(ptr);                                    \
 293         barrier_nospec();                                       \
 294         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 295         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 296         __gu_err;                                               \
 297 })
 298
 299
 300 /* more complex routines */
 301
 302 extern unsigned long __copy_tofrom_user(void __user *to,
 303                 const void __user *from, unsigned long size);
 304
 305 #ifdef __powerpc64__
 306 static inline unsigned long
 307 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 308 {
 309         return __copy_tofrom_user(to, from, n);
 310 }
 311 #endif /* __powerpc64__ */
 312
 313 static inline unsigned long raw_copy_from_user(void *to,
 314                 const void __user *from, unsigned long n)
 315 {
 316         if (__builtin_constant_p(n) && (n <= 8)) {
 317                 unsigned long ret = 1;
 318
 319                 switch (n) {
 320                 case 1:
 321                         barrier_nospec();
 322                         __get_user_size(*(u8 *)to, from, 1, ret);
 323                         break;
 324                 case 2:
 325                         barrier_nospec();
 326                         __get_user_size(*(u16 *)to, from, 2, ret);
 327                         break;
 328                 case 4:
 329                         barrier_nospec();
 330                         __get_user_size(*(u32 *)to, from, 4, ret);
 331                         break;
 332                 case 8:
 333                         barrier_nospec();
 334                         __get_user_size(*(u64 *)to, from, 8, ret);
 335                         break;
 336                 }
 337                 if (ret == 0)
 338                         return 0;
 339         }
 340
 341         barrier_nospec();
 342         return __copy_tofrom_user((__force void __user *)to, from, n);
 343 }
 344
 345 static inline unsigned long raw_copy_to_user(void __user *to,
 346                 const void *from, unsigned long n)
 347 {
 348         if (__builtin_constant_p(n) && (n <= 8)) {
 349                 unsigned long ret = 1;
 350
 351                 switch (n) {
 352                 case 1:
 353                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 354                         break;
 355                 case 2:
 356                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 357                         break;
 358                 case 4:
 359                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 360                         break;
 361                 case 8:
 362                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 363                         break;
 364                 }
 365                 if (ret == 0)
 366                         return 0;
 367         }
 368
 369         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 370 }
 371
 372 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 373
 374 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 375 {
 376         might_fault();
 377         if (likely(access_ok(addr, size)))
 378                 return __clear_user(addr, size);
 379         return size;
 380 }
 381
 382 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 383 extern __must_check long strnlen_user(const char __user *str, long n);
 384
 385 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
 386                 unsigned size);
 387 extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
 388                            size_t len);
 389
 390 #endif  /* _ARCH_POWERPC_UACCESS_H */