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 #include <asm/kup.h>
  10
  11 #ifdef __powerpc64__
  12 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
  13 #define TASK_SIZE_MAX           TASK_SIZE_USER64
  14 #else
  15 #define TASK_SIZE_MAX           TASK_SIZE
  16 #endif
  17
  18 static inline bool __access_ok(unsigned long addr, unsigned long size)
  19 {
  20         return addr < TASK_SIZE_MAX && size <= TASK_SIZE_MAX - addr;
  21 }
  22
  23 #define access_ok(addr, size)           \
  24         (__chk_user_ptr(addr),          \
  25          __access_ok((unsigned long)(addr), (size)))
  26
  27 /*
  28  * These are the main single-value transfer routines.  They automatically
  29  * use the right size if we just have the right pointer type.
  30  *
  31  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  32  * and yet we don't want to do any pointers, because that is too much
  33  * of a performance impact. Thus we have a few rather ugly macros here,
  34  * and hide all the ugliness from the user.
  35  *
  36  * The "__xxx" versions of the user access functions are versions that
  37  * do not verify the address space, that must have been done previously
  38  * with a separate "access_ok()" call (this is used when we do multiple
  39  * accesses to the same area of user memory).
  40  *
  41  * As we use the same address space for kernel and user data on the
  42  * PowerPC, we can just do these as direct assignments.  (Of course, the
  43  * exception handling means that it's no longer "just"...)
  44  *
  45  */
  46 #define __put_user(x, ptr)                                      \
  47 ({                                                              \
  48         long __pu_err;                                          \
  49         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
  50         __typeof__(*(ptr)) __pu_val = (__typeof__(*(ptr)))(x);  \
  51         __typeof__(sizeof(*(ptr))) __pu_size = sizeof(*(ptr));  \
  52                                                                 \
  53         might_fault();                                          \
  54         do {                                                    \
  55                 __label__ __pu_failed;                          \
  56                                                                 \
  57                 allow_write_to_user(__pu_addr, __pu_size);      \
  58                 __put_user_size_goto(__pu_val, __pu_addr, __pu_size, __pu_failed);      \
  59                 prevent_write_to_user(__pu_addr, __pu_size);    \
  60                 __pu_err = 0;                                   \
  61                 break;                                          \
  62                                                                 \
  63 __pu_failed:                                                    \
  64                 prevent_write_to_user(__pu_addr, __pu_size);    \
  65                 __pu_err = -EFAULT;                             \
  66         } while (0);                                            \
  67                                                                 \
  68         __pu_err;                                               \
  69 })
  70
  71 #define put_user(x, ptr)                                                \
  72 ({                                                                      \
  73         __typeof__(*(ptr)) __user *_pu_addr = (ptr);                    \
  74                                                                         \
  75         access_ok(_pu_addr, sizeof(*(ptr))) ?                           \
  76                   __put_user(x, _pu_addr) : -EFAULT;                    \
  77 })
  78
  79 /*
  80  * We don't tell gcc that we are accessing memory, but this is OK
  81  * because we do not write to any memory gcc knows about, so there
  82  * are no aliasing issues.
  83  */
  84 #define __put_user_asm_goto(x, addr, label, op)                 \
  85         asm_volatile_goto(                                      \
  86                 "1:     " op "%U1%X1 %0,%1      # put_user\n"   \
  87                 EX_TABLE(1b, %l2)                               \
  88                 :                                               \
  89                 : "r" (x), "m"UPD_CONSTR (*addr)                \
  90                 :                                               \
  91                 : label)
  92
  93 #ifdef __powerpc64__
  94 #define __put_user_asm2_goto(x, ptr, label)                     \
  95         __put_user_asm_goto(x, ptr, label, "std")
  96 #else /* __powerpc64__ */
  97 #define __put_user_asm2_goto(x, addr, label)                    \
  98         asm_volatile_goto(                                      \
  99                 "1:     stw%X1 %0, %1\n"                        \
 100                 "2:     stw%X1 %L0, %L1\n"                      \
 101                 EX_TABLE(1b, %l2)                               \
 102                 EX_TABLE(2b, %l2)                               \
 103                 :                                               \
 104                 : "r" (x), "m" (*addr)                          \
 105                 :                                               \
 106                 : label)
 107 #endif /* __powerpc64__ */
 108
 109 #define __put_user_size_goto(x, ptr, size, label)               \
 110 do {                                                            \
 111         __typeof__(*(ptr)) __user *__pus_addr = (ptr);          \
 112                                                                 \
 113         switch (size) {                                         \
 114         case 1: __put_user_asm_goto(x, __pus_addr, label, "stb"); break;        \
 115         case 2: __put_user_asm_goto(x, __pus_addr, label, "sth"); break;        \
 116         case 4: __put_user_asm_goto(x, __pus_addr, label, "stw"); break;        \
 117         case 8: __put_user_asm2_goto(x, __pus_addr, label); break;              \
 118         default: BUILD_BUG();                                   \
 119         }                                                       \
 120 } while (0)
 121
 122 /*
 123  * This does an atomic 128 byte aligned load from userspace.
 124  * Upto caller to do enable_kernel_vmx() before calling!
 125  */
 126 #define __get_user_atomic_128_aligned(kaddr, uaddr, err)                \
 127         __asm__ __volatile__(                           \
 128                 ".machine push\n"                       \
 129                 ".machine altivec\n"                    \
 130                 "1:     lvx  0,0,%1     # get user\n"   \
 131                 "       stvx 0,0,%2     # put kernel\n" \
 132                 ".machine pop\n"                        \
 133                 "2:\n"                                  \
 134                 ".section .fixup,\"ax\"\n"              \
 135                 "3:     li %0,%3\n"                     \
 136                 "       b 2b\n"                         \
 137                 ".previous\n"                           \
 138                 EX_TABLE(1b, 3b)                        \
 139                 : "=r" (err)                    \
 140                 : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err))
 141
 142 #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
 143
 144 #define __get_user_asm_goto(x, addr, label, op)                 \
 145         asm_volatile_goto(                                      \
 146                 "1:     "op"%U1%X1 %0, %1       # get_user\n"   \
 147                 EX_TABLE(1b, %l2)                               \
 148                 : "=r" (x)                                      \
 149                 : "m"UPD_CONSTR (*addr)                         \
 150                 :                                               \
 151                 : label)
 152
 153 #ifdef __powerpc64__
 154 #define __get_user_asm2_goto(x, addr, label)                    \
 155         __get_user_asm_goto(x, addr, label, "ld")
 156 #else /* __powerpc64__ */
 157 #define __get_user_asm2_goto(x, addr, label)                    \
 158         asm_volatile_goto(                                      \
 159                 "1:     lwz%X1 %0, %1\n"                        \
 160                 "2:     lwz%X1 %L0, %L1\n"                      \
 161                 EX_TABLE(1b, %l2)                               \
 162                 EX_TABLE(2b, %l2)                               \
 163                 : "=&r" (x)                                     \
 164                 : "m" (*addr)                                   \
 165                 :                                               \
 166                 : label)
 167 #endif /* __powerpc64__ */
 168
 169 #define __get_user_size_goto(x, ptr, size, label)                               \
 170 do {                                                                            \
 171         BUILD_BUG_ON(size > sizeof(x));                                         \
 172         switch (size) {                                                         \
 173         case 1: __get_user_asm_goto(x, (u8 __user *)ptr, label, "lbz"); break;  \
 174         case 2: __get_user_asm_goto(x, (u16 __user *)ptr, label, "lhz"); break; \
 175         case 4: __get_user_asm_goto(x, (u32 __user *)ptr, label, "lwz"); break; \
 176         case 8: __get_user_asm2_goto(x, (u64 __user *)ptr, label);  break;      \
 177         default: x = 0; BUILD_BUG();                                            \
 178         }                                                                       \
 179 } while (0)
 180
 181 #define __get_user_size_allowed(x, ptr, size, retval)                   \
 182 do {                                                                    \
 183                 __label__ __gus_failed;                                 \
 184                                                                         \
 185                 __get_user_size_goto(x, ptr, size, __gus_failed);       \
 186                 retval = 0;                                             \
 187                 break;                                                  \
 188 __gus_failed:                                                           \
 189                 x = 0;                                                  \
 190                 retval = -EFAULT;                                       \
 191 } while (0)
 192
 193 #else /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
 194
 195 #define __get_user_asm(x, addr, err, op)                \
 196         __asm__ __volatile__(                           \
 197                 "1:     "op"%U2%X2 %1, %2       # get_user\n"   \
 198                 "2:\n"                                  \
 199                 ".section .fixup,\"ax\"\n"              \
 200                 "3:     li %0,%3\n"                     \
 201                 "       li %1,0\n"                      \
 202                 "       b 2b\n"                         \
 203                 ".previous\n"                           \
 204                 EX_TABLE(1b, 3b)                        \
 205                 : "=r" (err), "=r" (x)                  \
 206                 : "m"UPD_CONSTR (*addr), "i" (-EFAULT), "0" (err))
 207
 208 #ifdef __powerpc64__
 209 #define __get_user_asm2(x, addr, err)                   \
 210         __get_user_asm(x, addr, err, "ld")
 211 #else /* __powerpc64__ */
 212 #define __get_user_asm2(x, addr, err)                   \
 213         __asm__ __volatile__(                           \
 214                 "1:     lwz%X2 %1, %2\n"                        \
 215                 "2:     lwz%X2 %L1, %L2\n"              \
 216                 "3:\n"                                  \
 217                 ".section .fixup,\"ax\"\n"              \
 218                 "4:     li %0,%3\n"                     \
 219                 "       li %1,0\n"                      \
 220                 "       li %1+1,0\n"                    \
 221                 "       b 3b\n"                         \
 222                 ".previous\n"                           \
 223                 EX_TABLE(1b, 4b)                        \
 224                 EX_TABLE(2b, 4b)                        \
 225                 : "=r" (err), "=&r" (x)                 \
 226                 : "m" (*addr), "i" (-EFAULT), "0" (err))
 227 #endif /* __powerpc64__ */
 228
 229 #define __get_user_size_allowed(x, ptr, size, retval)           \
 230 do {                                                            \
 231         retval = 0;                                             \
 232         BUILD_BUG_ON(size > sizeof(x));                         \
 233         switch (size) {                                         \
 234         case 1: __get_user_asm(x, (u8 __user *)ptr, retval, "lbz"); break;      \
 235         case 2: __get_user_asm(x, (u16 __user *)ptr, retval, "lhz"); break;     \
 236         case 4: __get_user_asm(x, (u32 __user *)ptr, retval, "lwz"); break;     \
 237         case 8: __get_user_asm2(x, (u64 __user *)ptr, retval);  break;  \
 238         default: x = 0; BUILD_BUG();                            \
 239         }                                                       \
 240 } while (0)
 241
 242 #define __get_user_size_goto(x, ptr, size, label)               \
 243 do {                                                            \
 244         long __gus_retval;                                      \
 245                                                                 \
 246         __get_user_size_allowed(x, ptr, size, __gus_retval);    \
 247         if (__gus_retval)                                       \
 248                 goto label;                                     \
 249 } while (0)
 250
 251 #endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
 252
 253 /*
 254  * This is a type: either unsigned long, if the argument fits into
 255  * that type, or otherwise unsigned long long.
 256  */
 257 #define __long_type(x) \
 258         __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 259
 260 #define __get_user(x, ptr)                                      \
 261 ({                                                              \
 262         long __gu_err;                                          \
 263         __long_type(*(ptr)) __gu_val;                           \
 264         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
 265         __typeof__(sizeof(*(ptr))) __gu_size = sizeof(*(ptr));  \
 266                                                                 \
 267         might_fault();                                  \
 268         allow_read_from_user(__gu_addr, __gu_size);             \
 269         __get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err);      \
 270         prevent_read_from_user(__gu_addr, __gu_size);           \
 271         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 272                                                                 \
 273         __gu_err;                                               \
 274 })
 275
 276 #define get_user(x, ptr)                                                \
 277 ({                                                                      \
 278         __typeof__(*(ptr)) __user *_gu_addr = (ptr);                    \
 279                                                                         \
 280         access_ok(_gu_addr, sizeof(*(ptr))) ?                           \
 281                   __get_user(x, _gu_addr) :                             \
 282                   ((x) = (__force __typeof__(*(ptr)))0, -EFAULT);       \
 283 })
 284
 285 /* more complex routines */
 286
 287 extern unsigned long __copy_tofrom_user(void __user *to,
 288                 const void __user *from, unsigned long size);
 289
 290 #ifdef __powerpc64__
 291 static inline unsigned long
 292 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 293 {
 294         unsigned long ret;
 295
 296         allow_read_write_user(to, from, n);
 297         ret = __copy_tofrom_user(to, from, n);
 298         prevent_read_write_user(to, from, n);
 299         return ret;
 300 }
 301 #endif /* __powerpc64__ */
 302
 303 static inline unsigned long raw_copy_from_user(void *to,
 304                 const void __user *from, unsigned long n)
 305 {
 306         unsigned long ret;
 307
 308         allow_read_from_user(from, n);
 309         ret = __copy_tofrom_user((__force void __user *)to, from, n);
 310         prevent_read_from_user(from, n);
 311         return ret;
 312 }
 313
 314 static inline unsigned long
 315 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 316 {
 317         unsigned long ret;
 318
 319         allow_write_to_user(to, n);
 320         ret = __copy_tofrom_user(to, (__force const void __user *)from, n);
 321         prevent_write_to_user(to, n);
 322         return ret;
 323 }
 324
 325 unsigned long __arch_clear_user(void __user *addr, unsigned long size);
 326
 327 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
 328 {
 329         unsigned long ret;
 330
 331         might_fault();
 332         allow_write_to_user(addr, size);
 333         ret = __arch_clear_user(addr, size);
 334         prevent_write_to_user(addr, size);
 335         return ret;
 336 }
 337
 338 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 339 {
 340         return likely(access_ok(addr, size)) ? __clear_user(addr, size) : size;
 341 }
 342
 343 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 344 extern __must_check long strnlen_user(const char __user *str, long n);
 345
 346 #ifdef CONFIG_ARCH_HAS_COPY_MC
 347 unsigned long __must_check
 348 copy_mc_generic(void *to, const void *from, unsigned long size);
 349
 350 static inline unsigned long __must_check
 351 copy_mc_to_kernel(void *to, const void *from, unsigned long size)
 352 {
 353         return copy_mc_generic(to, from, size);
 354 }
 355 #define copy_mc_to_kernel copy_mc_to_kernel
 356
 357 static inline unsigned long __must_check
 358 copy_mc_to_user(void __user *to, const void *from, unsigned long n)
 359 {
 360         if (likely(check_copy_size(from, n, true))) {
 361                 if (access_ok(to, n)) {
 362                         allow_write_to_user(to, n);
 363                         n = copy_mc_generic((void *)to, from, n);
 364                         prevent_write_to_user(to, n);
 365                 }
 366         }
 367
 368         return n;
 369 }
 370 #endif
 371
 372 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
 373                 unsigned size);
 374 extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
 375                            size_t len);
 376
 377 static __must_check inline bool user_access_begin(const void __user *ptr, size_t len)
 378 {
 379         if (unlikely(!access_ok(ptr, len)))
 380                 return false;
 381
 382         might_fault();
 383
 384         allow_read_write_user((void __user *)ptr, ptr, len);
 385         return true;
 386 }
 387 #define user_access_begin       user_access_begin
 388 #define user_access_end         prevent_current_access_user
 389 #define user_access_save        prevent_user_access_return
 390 #define user_access_restore     restore_user_access
 391
 392 static __must_check inline bool
 393 user_read_access_begin(const void __user *ptr, size_t len)
 394 {
 395         if (unlikely(!access_ok(ptr, len)))
 396                 return false;
 397
 398         might_fault();
 399
 400         allow_read_from_user(ptr, len);
 401         return true;
 402 }
 403 #define user_read_access_begin  user_read_access_begin
 404 #define user_read_access_end            prevent_current_read_from_user
 405
 406 static __must_check inline bool
 407 user_write_access_begin(const void __user *ptr, size_t len)
 408 {
 409         if (unlikely(!access_ok(ptr, len)))
 410                 return false;
 411
 412         might_fault();
 413
 414         allow_write_to_user((void __user *)ptr, len);
 415         return true;
 416 }
 417 #define user_write_access_begin user_write_access_begin
 418 #define user_write_access_end           prevent_current_write_to_user
 419
 420 #define unsafe_get_user(x, p, e) do {                                   \
 421         __long_type(*(p)) __gu_val;                             \
 422         __typeof__(*(p)) __user *__gu_addr = (p);               \
 423                                                                 \
 424         __get_user_size_goto(__gu_val, __gu_addr, sizeof(*(p)), e); \
 425         (x) = (__typeof__(*(p)))__gu_val;                       \
 426 } while (0)
 427
 428 #define unsafe_put_user(x, p, e) \
 429         __put_user_size_goto((__typeof__(*(p)))(x), (p), sizeof(*(p)), e)
 430
 431 #define unsafe_copy_from_user(d, s, l, e) \
 432 do {                                                                                    \
 433         u8 *_dst = (u8 *)(d);                                                           \
 434         const u8 __user *_src = (const u8 __user *)(s);                                 \
 435         size_t _len = (l);                                                              \
 436         int _i;                                                                         \
 437                                                                                         \
 438         for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64))               \
 439                 unsafe_get_user(*(u64 *)(_dst + _i), (u64 __user *)(_src + _i), e);     \
 440         if (_len & 4) {                                                                 \
 441                 unsafe_get_user(*(u32 *)(_dst + _i), (u32 __user *)(_src + _i), e);     \
 442                 _i += 4;                                                                \
 443         }                                                                               \
 444         if (_len & 2) {                                                                 \
 445                 unsafe_get_user(*(u16 *)(_dst + _i), (u16 __user *)(_src + _i), e);     \
 446                 _i += 2;                                                                \
 447         }                                                                               \
 448         if (_len & 1)                                                                   \
 449                 unsafe_get_user(*(u8 *)(_dst + _i), (u8 __user *)(_src + _i), e);       \
 450 } while (0)
 451
 452 #define unsafe_copy_to_user(d, s, l, e) \
 453 do {                                                                    \
 454         u8 __user *_dst = (u8 __user *)(d);                             \
 455         const u8 *_src = (const u8 *)(s);                               \
 456         size_t _len = (l);                                              \
 457         int _i;                                                         \
 458                                                                         \
 459         for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64))       \
 460                 unsafe_put_user(*(u64 *)(_src + _i), (u64 __user *)(_dst + _i), e); \
 461         if (_len & 4) {                                                 \
 462                 unsafe_put_user(*(u32*)(_src + _i), (u32 __user *)(_dst + _i), e); \
 463                 _i += 4;                                                \
 464         }                                                               \
 465         if (_len & 2) {                                                 \
 466                 unsafe_put_user(*(u16*)(_src + _i), (u16 __user *)(_dst + _i), e); \
 467                 _i += 2;                                                \
 468         }                                                               \
 469         if (_len & 1) \
 470                 unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \
 471 } while (0)
 472
 473 #define HAVE_GET_KERNEL_NOFAULT
 474
 475 #define __get_kernel_nofault(dst, src, type, err_label)                 \
 476         __get_user_size_goto(*((type *)(dst)),                          \
 477                 (__force type __user *)(src), sizeof(type), err_label)
 478
 479 #define __put_kernel_nofault(dst, src, type, err_label)                 \
 480         __put_user_size_goto(*((type *)(src)),                          \
 481                 (__force type __user *)(dst), sizeof(type), err_label)
 482
 483 #endif  /* _ARCH_POWERPC_UACCESS_H */