arch/x86/include/asm/uaccess.h

   1 #ifndef _ASM_X86_UACCESS_H
   2 #define _ASM_X86_UACCESS_H
   3 /*
   4  * User space memory access functions
   5  */
   6 #include <linux/errno.h>
   7 #include <linux/compiler.h>
   8 #include <linux/thread_info.h>
   9 #include <linux/string.h>
  10 #include <asm/asm.h>
  11 #include <asm/page.h>
  12 #include <asm/smap.h>
  13
  14 #define VERIFY_READ 0
  15 #define VERIFY_WRITE 1
  16
  17 /*
  18  * The fs value determines whether argument validity checking should be
  19  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  20  * get_fs() == KERNEL_DS, checking is bypassed.
  21  *
  22  * For historical reasons, these macros are grossly misnamed.
  23  */
  24
  25 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  26
  27 #define KERNEL_DS       MAKE_MM_SEG(-1UL)
  28 #define USER_DS         MAKE_MM_SEG(TASK_SIZE_MAX)
  29
  30 #define get_ds()        (KERNEL_DS)
  31 #define get_fs()        (current_thread_info()->addr_limit)
  32 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  33
  34 #define segment_eq(a, b)        ((a).seg == (b).seg)
  35
  36 #define user_addr_max() (current_thread_info()->addr_limit.seg)
  37 #define __addr_ok(addr)         \
  38         ((unsigned long __force)(addr) < user_addr_max())
  39
  40 /*
  41  * Test whether a block of memory is a valid user space address.
  42  * Returns 0 if the range is valid, nonzero otherwise.
  43  */
  44 static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit)
  45 {
  46         /*
  47          * If we have used "sizeof()" for the size,
  48          * we know it won't overflow the limit (but
  49          * it might overflow the 'addr', so it's
  50          * important to subtract the size from the
  51          * limit, not add it to the address).
  52          */
  53         if (__builtin_constant_p(size))
  54                 return unlikely(addr > limit - size);
  55
  56         /* Arbitrary sizes? Be careful about overflow */
  57         addr += size;
  58         if (unlikely(addr < size))
  59                 return true;
  60         return unlikely(addr > limit);
  61 }
  62
  63 #define __range_not_ok(addr, size, limit)                               \
  64 ({                                                                      \
  65         __chk_user_ptr(addr);                                           \
  66         __chk_range_not_ok((unsigned long __force)(addr), size, limit); \
  67 })
  68
  69 /**
  70  * access_ok: - Checks if a user space pointer is valid
  71  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
  72  *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
  73  *        to write to a block, it is always safe to read from it.
  74  * @addr: User space pointer to start of block to check
  75  * @size: Size of block to check
  76  *
  77  * Context: User context only. This function may sleep if pagefaults are
  78  *          enabled.
  79  *
  80  * Checks if a pointer to a block of memory in user space is valid.
  81  *
  82  * Returns true (nonzero) if the memory block may be valid, false (zero)
  83  * if it is definitely invalid.
  84  *
  85  * Note that, depending on architecture, this function probably just
  86  * checks that the pointer is in the user space range - after calling
  87  * this function, memory access functions may still return -EFAULT.
  88  */
  89 #define access_ok(type, addr, size) \
  90         likely(!__range_not_ok(addr, size, user_addr_max()))
  91
  92 /*
  93  * The exception table consists of pairs of addresses relative to the
  94  * exception table enty itself: the first is the address of an
  95  * instruction that is allowed to fault, and the second is the address
  96  * at which the program should continue.  No registers are modified,
  97  * so it is entirely up to the continuation code to figure out what to
  98  * do.
  99  *
 100  * All the routines below use bits of fixup code that are out of line
 101  * with the main instruction path.  This means when everything is well,
 102  * we don't even have to jump over them.  Further, they do not intrude
 103  * on our cache or tlb entries.
 104  */
 105
 106 struct exception_table_entry {
 107         int insn, fixup;
 108 };
 109 /* This is not the generic standard exception_table_entry format */
 110 #define ARCH_HAS_SORT_EXTABLE
 111 #define ARCH_HAS_SEARCH_EXTABLE
 112
 113 extern int fixup_exception(struct pt_regs *regs);
 114 extern int early_fixup_exception(unsigned long *ip);
 115
 116 /*
 117  * These are the main single-value transfer routines.  They automatically
 118  * use the right size if we just have the right pointer type.
 119  *
 120  * This gets kind of ugly. We want to return _two_ values in "get_user()"
 121  * and yet we don't want to do any pointers, because that is too much
 122  * of a performance impact. Thus we have a few rather ugly macros here,
 123  * and hide all the ugliness from the user.
 124  *
 125  * The "__xxx" versions of the user access functions are versions that
 126  * do not verify the address space, that must have been done previously
 127  * with a separate "access_ok()" call (this is used when we do multiple
 128  * accesses to the same area of user memory).
 129  */
 130
 131 extern int __get_user_1(void);
 132 extern int __get_user_2(void);
 133 extern int __get_user_4(void);
 134 extern int __get_user_8(void);
 135 extern int __get_user_bad(void);
 136
 137 #define __uaccess_begin() stac()
 138 #define __uaccess_end()   clac()
 139
 140 /*
 141  * This is a type: either unsigned long, if the argument fits into
 142  * that type, or otherwise unsigned long long.
 143  */
 144 #define __inttype(x) \
 145 __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 146
 147 /**
 148  * get_user: - Get a simple variable from user space.
 149  * @x:   Variable to store result.
 150  * @ptr: Source address, in user space.
 151  *
 152  * Context: User context only. This function may sleep if pagefaults are
 153  *          enabled.
 154  *
 155  * This macro copies a single simple variable from user space to kernel
 156  * space.  It supports simple types like char and int, but not larger
 157  * data types like structures or arrays.
 158  *
 159  * @ptr must have pointer-to-simple-variable type, and the result of
 160  * dereferencing @ptr must be assignable to @x without a cast.
 161  *
 162  * Returns zero on success, or -EFAULT on error.
 163  * On error, the variable @x is set to zero.
 164  */
 165 /*
 166  * Careful: we have to cast the result to the type of the pointer
 167  * for sign reasons.
 168  *
 169  * The use of _ASM_DX as the register specifier is a bit of a
 170  * simplification, as gcc only cares about it as the starting point
 171  * and not size: for a 64-bit value it will use %ecx:%edx on 32 bits
 172  * (%ecx being the next register in gcc's x86 register sequence), and
 173  * %rdx on 64 bits.
 174  *
 175  * Clang/LLVM cares about the size of the register, but still wants
 176  * the base register for something that ends up being a pair.
 177  */
 178 #define get_user(x, ptr)                                                \
 179 ({                                                                      \
 180         int __ret_gu;                                                   \
 181         register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX);            \
 182         __chk_user_ptr(ptr);                                            \
 183         might_fault();                                                  \
 184         asm volatile("call __get_user_%P3"                              \
 185                      : "=a" (__ret_gu), "=r" (__val_gu)                 \
 186                      : "0" (ptr), "i" (sizeof(*(ptr))));                \
 187         (x) = (__force __typeof__(*(ptr))) __val_gu;                    \
 188         __builtin_expect(__ret_gu, 0);                                  \
 189 })
 190
 191 #define __put_user_x(size, x, ptr, __ret_pu)                    \
 192         asm volatile("call __put_user_" #size : "=a" (__ret_pu) \
 193                      : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
 194
 195
 196
 197 #ifdef CONFIG_X86_32
 198 #define __put_user_asm_u64(x, addr, err, errret)                        \
 199         asm volatile("\n"                                               \
 200                      "1:        movl %%eax,0(%2)\n"                     \
 201                      "2:        movl %%edx,4(%2)\n"                     \
 202                      "3:"                                               \
 203                      ".section .fixup,\"ax\"\n"                         \
 204                      "4:        movl %3,%0\n"                           \
 205                      "  jmp 3b\n"                                       \
 206                      ".previous\n"                                      \
 207                      _ASM_EXTABLE(1b, 4b)                               \
 208                      _ASM_EXTABLE(2b, 4b)                               \
 209                      : "=r" (err)                                       \
 210                      : "A" (x), "r" (addr), "i" (errret), "0" (err))
 211
 212 #define __put_user_asm_ex_u64(x, addr)                                  \
 213         asm volatile("\n"                                               \
 214                      "1:        movl %%eax,0(%1)\n"                     \
 215                      "2:        movl %%edx,4(%1)\n"                     \
 216                      "3:"                                               \
 217                      _ASM_EXTABLE_EX(1b, 2b)                            \
 218                      _ASM_EXTABLE_EX(2b, 3b)                            \
 219                      : : "A" (x), "r" (addr))
 220
 221 #define __put_user_x8(x, ptr, __ret_pu)                         \
 222         asm volatile("call __put_user_8" : "=a" (__ret_pu)      \
 223                      : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
 224 #else
 225 #define __put_user_asm_u64(x, ptr, retval, errret) \
 226         __put_user_asm(x, ptr, retval, "q", "", "er", errret)
 227 #define __put_user_asm_ex_u64(x, addr)  \
 228         __put_user_asm_ex(x, addr, "q", "", "er")
 229 #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
 230 #endif
 231
 232 extern void __put_user_bad(void);
 233
 234 /*
 235  * Strange magic calling convention: pointer in %ecx,
 236  * value in %eax(:%edx), return value in %eax. clobbers %rbx
 237  */
 238 extern void __put_user_1(void);
 239 extern void __put_user_2(void);
 240 extern void __put_user_4(void);
 241 extern void __put_user_8(void);
 242
 243 /**
 244  * put_user: - Write a simple value into user space.
 245  * @x:   Value to copy to user space.
 246  * @ptr: Destination address, in user space.
 247  *
 248  * Context: User context only. This function may sleep if pagefaults are
 249  *          enabled.
 250  *
 251  * This macro copies a single simple value from kernel space to user
 252  * space.  It supports simple types like char and int, but not larger
 253  * data types like structures or arrays.
 254  *
 255  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 256  * to the result of dereferencing @ptr.
 257  *
 258  * Returns zero on success, or -EFAULT on error.
 259  */
 260 #define put_user(x, ptr)                                        \
 261 ({                                                              \
 262         int __ret_pu;                                           \
 263         __typeof__(*(ptr)) __pu_val;                            \
 264         __chk_user_ptr(ptr);                                    \
 265         might_fault();                                          \
 266         __pu_val = x;                                           \
 267         switch (sizeof(*(ptr))) {                               \
 268         case 1:                                                 \
 269                 __put_user_x(1, __pu_val, ptr, __ret_pu);       \
 270                 break;                                          \
 271         case 2:                                                 \
 272                 __put_user_x(2, __pu_val, ptr, __ret_pu);       \
 273                 break;                                          \
 274         case 4:                                                 \
 275                 __put_user_x(4, __pu_val, ptr, __ret_pu);       \
 276                 break;                                          \
 277         case 8:                                                 \
 278                 __put_user_x8(__pu_val, ptr, __ret_pu);         \
 279                 break;                                          \
 280         default:                                                \
 281                 __put_user_x(X, __pu_val, ptr, __ret_pu);       \
 282                 break;                                          \
 283         }                                                       \
 284         __builtin_expect(__ret_pu, 0);                          \
 285 })
 286
 287 #define __put_user_size(x, ptr, size, retval, errret)                   \
 288 do {                                                                    \
 289         retval = 0;                                                     \
 290         __chk_user_ptr(ptr);                                            \
 291         switch (size) {                                                 \
 292         case 1:                                                         \
 293                 __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \
 294                 break;                                                  \
 295         case 2:                                                         \
 296                 __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \
 297                 break;                                                  \
 298         case 4:                                                         \
 299                 __put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \
 300                 break;                                                  \
 301         case 8:                                                         \
 302                 __put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval,  \
 303                                    errret);                             \
 304                 break;                                                  \
 305         default:                                                        \
 306                 __put_user_bad();                                       \
 307         }                                                               \
 308 } while (0)
 309
 310 /*
 311  * This doesn't do __uaccess_begin/end - the exception handling
 312  * around it must do that.
 313  */
 314 #define __put_user_size_ex(x, ptr, size)                                \
 315 do {                                                                    \
 316         __chk_user_ptr(ptr);                                            \
 317         switch (size) {                                                 \
 318         case 1:                                                         \
 319                 __put_user_asm_ex(x, ptr, "b", "b", "iq");              \
 320                 break;                                                  \
 321         case 2:                                                         \
 322                 __put_user_asm_ex(x, ptr, "w", "w", "ir");              \
 323                 break;                                                  \
 324         case 4:                                                         \
 325                 __put_user_asm_ex(x, ptr, "l", "k", "ir");              \
 326                 break;                                                  \
 327         case 8:                                                         \
 328                 __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr);      \
 329                 break;                                                  \
 330         default:                                                        \
 331                 __put_user_bad();                                       \
 332         }                                                               \
 333 } while (0)
 334
 335 #ifdef CONFIG_X86_32
 336 #define __get_user_asm_u64(x, ptr, retval, errret)      (x) = __get_user_bad()
 337 #define __get_user_asm_ex_u64(x, ptr)                   (x) = __get_user_bad()
 338 #else
 339 #define __get_user_asm_u64(x, ptr, retval, errret) \
 340          __get_user_asm(x, ptr, retval, "q", "", "=r", errret)
 341 #define __get_user_asm_ex_u64(x, ptr) \
 342          __get_user_asm_ex(x, ptr, "q", "", "=r")
 343 #endif
 344
 345 #define __get_user_size(x, ptr, size, retval, errret)                   \
 346 do {                                                                    \
 347         retval = 0;                                                     \
 348         __chk_user_ptr(ptr);                                            \
 349         switch (size) {                                                 \
 350         case 1:                                                         \
 351                 __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \
 352                 break;                                                  \
 353         case 2:                                                         \
 354                 __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \
 355                 break;                                                  \
 356         case 4:                                                         \
 357                 __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \
 358                 break;                                                  \
 359         case 8:                                                         \
 360                 __get_user_asm_u64(x, ptr, retval, errret);             \
 361                 break;                                                  \
 362         default:                                                        \
 363                 (x) = __get_user_bad();                                 \
 364         }                                                               \
 365 } while (0)
 366
 367 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret)       \
 368         asm volatile("\n"                                               \
 369                      "1:        mov"itype" %2,%"rtype"1\n"              \
 370                      "2:\n"                                             \
 371                      ".section .fixup,\"ax\"\n"                         \
 372                      "3:        mov %3,%0\n"                            \
 373                      "  xor"itype" %"rtype"1,%"rtype"1\n"               \
 374                      "  jmp 2b\n"                                       \
 375                      ".previous\n"                                      \
 376                      _ASM_EXTABLE(1b, 3b)                               \
 377                      : "=r" (err), ltype(x)                             \
 378                      : "m" (__m(addr)), "i" (errret), "0" (err))
 379
 380 /*
 381  * This doesn't do __uaccess_begin/end - the exception handling
 382  * around it must do that.
 383  */
 384 #define __get_user_size_ex(x, ptr, size)                                \
 385 do {                                                                    \
 386         __chk_user_ptr(ptr);                                            \
 387         switch (size) {                                                 \
 388         case 1:                                                         \
 389                 __get_user_asm_ex(x, ptr, "b", "b", "=q");              \
 390                 break;                                                  \
 391         case 2:                                                         \
 392                 __get_user_asm_ex(x, ptr, "w", "w", "=r");              \
 393                 break;                                                  \
 394         case 4:                                                         \
 395                 __get_user_asm_ex(x, ptr, "l", "k", "=r");              \
 396                 break;                                                  \
 397         case 8:                                                         \
 398                 __get_user_asm_ex_u64(x, ptr);                          \
 399                 break;                                                  \
 400         default:                                                        \
 401                 (x) = __get_user_bad();                                 \
 402         }                                                               \
 403 } while (0)
 404
 405 #define __get_user_asm_ex(x, addr, itype, rtype, ltype)                 \
 406         asm volatile("1:        mov"itype" %1,%"rtype"0\n"              \
 407                      "2:\n"                                             \
 408                      ".section .fixup,\"ax\"\n"                         \
 409                      "3:xor"itype" %"rtype"0,%"rtype"0\n"               \
 410                      "  jmp 2b\n"                                       \
 411                      ".previous\n"                                      \
 412                      _ASM_EXTABLE_EX(1b, 3b)                            \
 413                      : ltype(x) : "m" (__m(addr)))
 414
 415 #define __put_user_nocheck(x, ptr, size)                        \
 416 ({                                                              \
 417         int __pu_err;                                           \
 418         __uaccess_begin();                                      \
 419         __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \
 420         __uaccess_end();                                        \
 421         __builtin_expect(__pu_err, 0);                          \
 422 })
 423
 424 #define __get_user_nocheck(x, ptr, size)                                \
 425 ({                                                                      \
 426         int __gu_err;                                                   \
 427         unsigned long __gu_val;                                         \
 428         __uaccess_begin();                                              \
 429         __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT);    \
 430         __uaccess_end();                                                \
 431         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 432         __builtin_expect(__gu_err, 0);                                  \
 433 })
 434
 435 /* FIXME: this hack is definitely wrong -AK */
 436 struct __large_struct { unsigned long buf[100]; };
 437 #define __m(x) (*(struct __large_struct __user *)(x))
 438
 439 /*
 440  * Tell gcc we read from memory instead of writing: this is because
 441  * we do not write to any memory gcc knows about, so there are no
 442  * aliasing issues.
 443  */
 444 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret)       \
 445         asm volatile("\n"                                               \
 446                      "1:        mov"itype" %"rtype"1,%2\n"              \
 447                      "2:\n"                                             \
 448                      ".section .fixup,\"ax\"\n"                         \
 449                      "3:        mov %3,%0\n"                            \
 450                      "  jmp 2b\n"                                       \
 451                      ".previous\n"                                      \
 452                      _ASM_EXTABLE(1b, 3b)                               \
 453                      : "=r"(err)                                        \
 454                      : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))
 455
 456 #define __put_user_asm_ex(x, addr, itype, rtype, ltype)                 \
 457         asm volatile("1:        mov"itype" %"rtype"0,%1\n"              \
 458                      "2:\n"                                             \
 459                      _ASM_EXTABLE_EX(1b, 2b)                            \
 460                      : : ltype(x), "m" (__m(addr)))
 461
 462 /*
 463  * uaccess_try and catch
 464  */
 465 #define uaccess_try     do {                                            \
 466         current_thread_info()->uaccess_err = 0;                         \
 467         __uaccess_begin();                                              \
 468         barrier();
 469
 470 #define uaccess_catch(err)                                              \
 471         __uaccess_end();                                                \
 472         (err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0);    \
 473 } while (0)
 474
 475 /**
 476  * __get_user: - Get a simple variable from user space, with less checking.
 477  * @x:   Variable to store result.
 478  * @ptr: Source address, in user space.
 479  *
 480  * Context: User context only. This function may sleep if pagefaults are
 481  *          enabled.
 482  *
 483  * This macro copies a single simple variable from user space to kernel
 484  * space.  It supports simple types like char and int, but not larger
 485  * data types like structures or arrays.
 486  *
 487  * @ptr must have pointer-to-simple-variable type, and the result of
 488  * dereferencing @ptr must be assignable to @x without a cast.
 489  *
 490  * Caller must check the pointer with access_ok() before calling this
 491  * function.
 492  *
 493  * Returns zero on success, or -EFAULT on error.
 494  * On error, the variable @x is set to zero.
 495  */
 496
 497 #define __get_user(x, ptr)                                              \
 498         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 499
 500 /**
 501  * __put_user: - Write a simple value into user space, with less checking.
 502  * @x:   Value to copy to user space.
 503  * @ptr: Destination address, in user space.
 504  *
 505  * Context: User context only. This function may sleep if pagefaults are
 506  *          enabled.
 507  *
 508  * This macro copies a single simple value from kernel space to user
 509  * space.  It supports simple types like char and int, but not larger
 510  * data types like structures or arrays.
 511  *
 512  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 513  * to the result of dereferencing @ptr.
 514  *
 515  * Caller must check the pointer with access_ok() before calling this
 516  * function.
 517  *
 518  * Returns zero on success, or -EFAULT on error.
 519  */
 520
 521 #define __put_user(x, ptr)                                              \
 522         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 523
 524 #define __get_user_unaligned __get_user
 525 #define __put_user_unaligned __put_user
 526
 527 /*
 528  * {get|put}_user_try and catch
 529  *
 530  * get_user_try {
 531  *      get_user_ex(...);
 532  * } get_user_catch(err)
 533  */
 534 #define get_user_try            uaccess_try
 535 #define get_user_catch(err)     uaccess_catch(err)
 536
 537 #define get_user_ex(x, ptr)     do {                                    \
 538         unsigned long __gue_val;                                        \
 539         __get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr))));       \
 540         (x) = (__force __typeof__(*(ptr)))__gue_val;                    \
 541 } while (0)
 542
 543 #define put_user_try            uaccess_try
 544 #define put_user_catch(err)     uaccess_catch(err)
 545
 546 #define put_user_ex(x, ptr)                                             \
 547         __put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 548
 549 extern unsigned long
 550 copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
 551 extern __must_check long
 552 strncpy_from_user(char *dst, const char __user *src, long count);
 553
 554 extern __must_check long strlen_user(const char __user *str);
 555 extern __must_check long strnlen_user(const char __user *str, long n);
 556
 557 unsigned long __must_check clear_user(void __user *mem, unsigned long len);
 558 unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
 559
 560 extern void __cmpxchg_wrong_size(void)
 561         __compiletime_error("Bad argument size for cmpxchg");
 562
 563 #define __user_atomic_cmpxchg_inatomic(uval, ptr, old, new, size)       \
 564 ({                                                                      \
 565         int __ret = 0;                                                  \
 566         __typeof__(ptr) __uval = (uval);                                \
 567         __typeof__(*(ptr)) __old = (old);                               \
 568         __typeof__(*(ptr)) __new = (new);                               \
 569         __uaccess_begin();                                              \
 570         switch (size) {                                                 \
 571         case 1:                                                         \
 572         {                                                               \
 573                 asm volatile("\n"                                       \
 574                         "1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n"          \
 575                         "2:\n"                                          \
 576                         "\t.section .fixup, \"ax\"\n"                   \
 577                         "3:\tmov     %3, %0\n"                          \
 578                         "\tjmp     2b\n"                                \
 579                         "\t.previous\n"                                 \
 580                         _ASM_EXTABLE(1b, 3b)                            \
 581                         : "+r" (__ret), "=a" (__old), "+m" (*(ptr))     \
 582                         : "i" (-EFAULT), "q" (__new), "1" (__old)       \
 583                         : "memory"                                      \
 584                 );                                                      \
 585                 break;                                                  \
 586         }                                                               \
 587         case 2:                                                         \
 588         {                                                               \
 589                 asm volatile("\n"                                       \
 590                         "1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n"          \
 591                         "2:\n"                                          \
 592                         "\t.section .fixup, \"ax\"\n"                   \
 593                         "3:\tmov     %3, %0\n"                          \
 594                         "\tjmp     2b\n"                                \
 595                         "\t.previous\n"                                 \
 596                         _ASM_EXTABLE(1b, 3b)                            \
 597                         : "+r" (__ret), "=a" (__old), "+m" (*(ptr))     \
 598                         : "i" (-EFAULT), "r" (__new), "1" (__old)       \
 599                         : "memory"                                      \
 600                 );                                                      \
 601                 break;                                                  \
 602         }                                                               \
 603         case 4:                                                         \
 604         {                                                               \
 605                 asm volatile("\n"                                       \
 606                         "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"          \
 607                         "2:\n"                                          \
 608                         "\t.section .fixup, \"ax\"\n"                   \
 609                         "3:\tmov     %3, %0\n"                          \
 610                         "\tjmp     2b\n"                                \
 611                         "\t.previous\n"                                 \
 612                         _ASM_EXTABLE(1b, 3b)                            \
 613                         : "+r" (__ret), "=a" (__old), "+m" (*(ptr))     \
 614                         : "i" (-EFAULT), "r" (__new), "1" (__old)       \
 615                         : "memory"                                      \
 616                 );                                                      \
 617                 break;                                                  \
 618         }                                                               \
 619         case 8:                                                         \
 620         {                                                               \
 621                 if (!IS_ENABLED(CONFIG_X86_64))                         \
 622                         __cmpxchg_wrong_size();                         \
 623                                                                         \
 624                 asm volatile("\n"                                       \
 625                         "1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n"          \
 626                         "2:\n"                                          \
 627                         "\t.section .fixup, \"ax\"\n"                   \
 628                         "3:\tmov     %3, %0\n"                          \
 629                         "\tjmp     2b\n"                                \
 630                         "\t.previous\n"                                 \
 631                         _ASM_EXTABLE(1b, 3b)                            \
 632                         : "+r" (__ret), "=a" (__old), "+m" (*(ptr))     \
 633                         : "i" (-EFAULT), "r" (__new), "1" (__old)       \
 634                         : "memory"                                      \
 635                 );                                                      \
 636                 break;                                                  \
 637         }                                                               \
 638         default:                                                        \
 639                 __cmpxchg_wrong_size();                                 \
 640         }                                                               \
 641         __uaccess_end();                                                \
 642         *__uval = __old;                                                \
 643         __ret;                                                          \
 644 })
 645
 646 #define user_atomic_cmpxchg_inatomic(uval, ptr, old, new)               \
 647 ({                                                                      \
 648         access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ?                \
 649                 __user_atomic_cmpxchg_inatomic((uval), (ptr),           \
 650                                 (old), (new), sizeof(*(ptr))) :         \
 651                 -EFAULT;                                                \
 652 })
 653
 654 /*
 655  * movsl can be slow when source and dest are not both 8-byte aligned
 656  */
 657 #ifdef CONFIG_X86_INTEL_USERCOPY
 658 extern struct movsl_mask {
 659         int mask;
 660 } ____cacheline_aligned_in_smp movsl_mask;
 661 #endif
 662
 663 #define ARCH_HAS_NOCACHE_UACCESS 1
 664
 665 #ifdef CONFIG_X86_32
 666 # include <asm/uaccess_32.h>
 667 #else
 668 # include <asm/uaccess_64.h>
 669 #endif
 670
 671 unsigned long __must_check _copy_from_user(void *to, const void __user *from,
 672                                            unsigned n);
 673 unsigned long __must_check _copy_to_user(void __user *to, const void *from,
 674                                          unsigned n);
 675
 676 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
 677 # define copy_user_diag __compiletime_error
 678 #else
 679 # define copy_user_diag __compiletime_warning
 680 #endif
 681
 682 extern void copy_user_diag("copy_from_user() buffer size is too small")
 683 copy_from_user_overflow(void);
 684 extern void copy_user_diag("copy_to_user() buffer size is too small")
 685 copy_to_user_overflow(void) __asm__("copy_from_user_overflow");
 686
 687 #undef copy_user_diag
 688
 689 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
 690
 691 extern void
 692 __compiletime_warning("copy_from_user() buffer size is not provably correct")
 693 __copy_from_user_overflow(void) __asm__("copy_from_user_overflow");
 694 #define __copy_from_user_overflow(size, count) __copy_from_user_overflow()
 695
 696 extern void
 697 __compiletime_warning("copy_to_user() buffer size is not provably correct")
 698 __copy_to_user_overflow(void) __asm__("copy_from_user_overflow");
 699 #define __copy_to_user_overflow(size, count) __copy_to_user_overflow()
 700
 701 #else
 702
 703 static inline void
 704 __copy_from_user_overflow(int size, unsigned long count)
 705 {
 706         WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
 707 }
 708
 709 #define __copy_to_user_overflow __copy_from_user_overflow
 710
 711 #endif
 712
 713 static inline unsigned long __must_check
 714 copy_from_user(void *to, const void __user *from, unsigned long n)
 715 {
 716         int sz = __compiletime_object_size(to);
 717
 718         might_fault();
 719
 720         /*
 721          * While we would like to have the compiler do the checking for us
 722          * even in the non-constant size case, any false positives there are
 723          * a problem (especially when DEBUG_STRICT_USER_COPY_CHECKS, but even
 724          * without - the [hopefully] dangerous looking nature of the warning
 725          * would make people go look at the respecitive call sites over and
 726          * over again just to find that there's no problem).
 727          *
 728          * And there are cases where it's just not realistic for the compiler
 729          * to prove the count to be in range. For example when multiple call
 730          * sites of a helper function - perhaps in different source files -
 731          * all doing proper range checking, yet the helper function not doing
 732          * so again.
 733          *
 734          * Therefore limit the compile time checking to the constant size
 735          * case, and do only runtime checking for non-constant sizes.
 736          */
 737
 738         if (likely(sz < 0 || sz >= n)) {
 739                 check_object_size(to, n, false);
 740                 n = _copy_from_user(to, from, n);
 741         } else if (__builtin_constant_p(n))
 742                 copy_from_user_overflow();
 743         else
 744                 __copy_from_user_overflow(sz, n);
 745
 746         return n;
 747 }
 748
 749 static inline unsigned long __must_check
 750 copy_to_user(void __user *to, const void *from, unsigned long n)
 751 {
 752         int sz = __compiletime_object_size(from);
 753
 754         might_fault();
 755
 756         /* See the comment in copy_from_user() above. */
 757         if (likely(sz < 0 || sz >= n)) {
 758                 check_object_size(from, n, true);
 759                 n = _copy_to_user(to, from, n);
 760         } else if (__builtin_constant_p(n))
 761                 copy_to_user_overflow();
 762         else
 763                 __copy_to_user_overflow(sz, n);
 764
 765         return n;
 766 }
 767
 768 #undef __copy_from_user_overflow
 769 #undef __copy_to_user_overflow
 770
 771 /*
 772  * The "unsafe" user accesses aren't really "unsafe", but the naming
 773  * is a big fat warning: you have to not only do the access_ok()
 774  * checking before using them, but you have to surround them with the
 775  * user_access_begin/end() pair.
 776  */
 777 #define user_access_begin()     __uaccess_begin()
 778 #define user_access_end()       __uaccess_end()
 779
 780 #define unsafe_put_user(x, ptr, err_label)                                      \
 781 do {                                                                            \
 782         int __pu_err;                                                           \
 783         __put_user_size((x), (ptr), sizeof(*(ptr)), __pu_err, -EFAULT);         \
 784         if (unlikely(__pu_err)) goto err_label;                                 \
 785 } while (0)
 786
 787 #define unsafe_get_user(x, ptr, err_label)                                      \
 788 do {                                                                            \
 789         int __gu_err;                                                           \
 790         unsigned long __gu_val;                                                 \
 791         __get_user_size(__gu_val, (ptr), sizeof(*(ptr)), __gu_err, -EFAULT);    \
 792         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 793         if (unlikely(__gu_err)) goto err_label;                                 \
 794 } while (0)
 795
 796 #endif /* _ASM_X86_UACCESS_H */
 797