arch/tile/include/asm/uaccess.h

   1 /*
   2  * Copyright 2010 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  */
  14
  15 #ifndef _ASM_TILE_UACCESS_H
  16 #define _ASM_TILE_UACCESS_H
  17
  18 /*
  19  * User space memory access functions
  20  */
  21 #include <linux/mm.h>
  22 #include <asm/processor.h>
  23 #include <asm/page.h>
  24
  25 /*
  26  * The fs value determines whether argument validity checking should be
  27  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  28  * get_fs() == KERNEL_DS, checking is bypassed.
  29  *
  30  * For historical reasons, these macros are grossly misnamed.
  31  */
  32 #define MAKE_MM_SEG(a)  ((mm_segment_t) { (a) })
  33
  34 #define KERNEL_DS       MAKE_MM_SEG(-1UL)
  35 #define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)
  36
  37 #define get_ds()        (KERNEL_DS)
  38 #define get_fs()        (current_thread_info()->addr_limit)
  39 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  40
  41 #define segment_eq(a, b) ((a).seg == (b).seg)
  42
  43 #ifndef __tilegx__
  44 /*
  45  * We could allow mapping all 16 MB at 0xfc000000, but we set up a
  46  * special hack in arch_setup_additional_pages() to auto-create a mapping
  47  * for the first 16 KB, and it would seem strange to have different
  48  * user-accessible semantics for memory at 0xfc000000 and above 0xfc004000.
  49  */
  50 static inline int is_arch_mappable_range(unsigned long addr,
  51                                          unsigned long size)
  52 {
  53         return (addr >= MEM_USER_INTRPT &&
  54                 addr < (MEM_USER_INTRPT + INTRPT_SIZE) &&
  55                 size <= (MEM_USER_INTRPT + INTRPT_SIZE) - addr);
  56 }
  57 #define is_arch_mappable_range is_arch_mappable_range
  58 #else
  59 #define is_arch_mappable_range(addr, size) 0
  60 #endif
  61
  62 /*
  63  * Note that using this definition ignores is_arch_mappable_range(),
  64  * so on tilepro code that uses user_addr_max() is constrained not
  65  * to reference the tilepro user-interrupt region.
  66  */
  67 #define user_addr_max() (current_thread_info()->addr_limit.seg)
  68
  69 /*
  70  * Test whether a block of memory is a valid user space address.
  71  * Returns 0 if the range is valid, nonzero otherwise.
  72  */
  73 int __range_ok(unsigned long addr, unsigned long size);
  74
  75 /**
  76  * access_ok: - Checks if a user space pointer is valid
  77  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
  78  *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
  79  *        to write to a block, it is always safe to read from it.
  80  * @addr: User space pointer to start of block to check
  81  * @size: Size of block to check
  82  *
  83  * Context: User context only. This function may sleep if pagefaults are
  84  *          enabled.
  85  *
  86  * Checks if a pointer to a block of memory in user space is valid.
  87  *
  88  * Returns true (nonzero) if the memory block may be valid, false (zero)
  89  * if it is definitely invalid.
  90  *
  91  * Note that, depending on architecture, this function probably just
  92  * checks that the pointer is in the user space range - after calling
  93  * this function, memory access functions may still return -EFAULT.
  94  */
  95 #define access_ok(type, addr, size) ({ \
  96         __chk_user_ptr(addr); \
  97         likely(__range_ok((unsigned long)(addr), (size)) == 0); \
  98 })
  99
 100 #include <asm/extable.h>
 101
 102 /*
 103  * This is a type: either unsigned long, if the argument fits into
 104  * that type, or otherwise unsigned long long.
 105  */
 106 #define __inttype(x) \
 107         __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 108
 109 /*
 110  * Support macros for __get_user().
 111  * Note that __get_user() and __put_user() assume proper alignment.
 112  */
 113
 114 #ifdef __LP64__
 115 #define _ASM_PTR        ".quad"
 116 #define _ASM_ALIGN      ".align 8"
 117 #else
 118 #define _ASM_PTR        ".long"
 119 #define _ASM_ALIGN      ".align 4"
 120 #endif
 121
 122 #define __get_user_asm(OP, x, ptr, ret)                                 \
 123         asm volatile("1: {" #OP " %1, %2; movei %0, 0 }\n"              \
 124                      ".pushsection .fixup,\"ax\"\n"                     \
 125                      "0: { movei %1, 0; movei %0, %3 }\n"               \
 126                      "j 9f\n"                                           \
 127                      ".section __ex_table,\"a\"\n"                      \
 128                      _ASM_ALIGN "\n"                                    \
 129                      _ASM_PTR " 1b, 0b\n"                               \
 130                      ".popsection\n"                                    \
 131                      "9:"                                               \
 132                      : "=r" (ret), "=r" (x)                             \
 133                      : "r" (ptr), "i" (-EFAULT))
 134
 135 #ifdef __tilegx__
 136 #define __get_user_1(x, ptr, ret) __get_user_asm(ld1u, x, ptr, ret)
 137 #define __get_user_2(x, ptr, ret) __get_user_asm(ld2u, x, ptr, ret)
 138 #define __get_user_4(x, ptr, ret) __get_user_asm(ld4s, x, ptr, ret)
 139 #define __get_user_8(x, ptr, ret) __get_user_asm(ld, x, ptr, ret)
 140 #else
 141 #define __get_user_1(x, ptr, ret) __get_user_asm(lb_u, x, ptr, ret)
 142 #define __get_user_2(x, ptr, ret) __get_user_asm(lh_u, x, ptr, ret)
 143 #define __get_user_4(x, ptr, ret) __get_user_asm(lw, x, ptr, ret)
 144 #ifdef __LITTLE_ENDIAN
 145 #define __lo32(a, b) a
 146 #define __hi32(a, b) b
 147 #else
 148 #define __lo32(a, b) b
 149 #define __hi32(a, b) a
 150 #endif
 151 #define __get_user_8(x, ptr, ret)                                       \
 152         ({                                                              \
 153                 unsigned int __a, __b;                                  \
 154                 asm volatile("1: { lw %1, %3; addi %2, %3, 4 }\n"       \
 155                              "2: { lw %2, %2; movei %0, 0 }\n"          \
 156                              ".pushsection .fixup,\"ax\"\n"             \
 157                              "0: { movei %1, 0; movei %2, 0 }\n"        \
 158                              "{ movei %0, %4; j 9f }\n"                 \
 159                              ".section __ex_table,\"a\"\n"              \
 160                              ".align 4\n"                               \
 161                              ".word 1b, 0b\n"                           \
 162                              ".word 2b, 0b\n"                           \
 163                              ".popsection\n"                            \
 164                              "9:"                                       \
 165                              : "=r" (ret), "=r" (__a), "=&r" (__b)      \
 166                              : "r" (ptr), "i" (-EFAULT));               \
 167                 (x) = (__force __typeof(x))(__inttype(x))               \
 168                         (((u64)__hi32(__a, __b) << 32) |                \
 169                          __lo32(__a, __b));                             \
 170         })
 171 #endif
 172
 173 extern int __get_user_bad(void)
 174   __attribute__((warning("sizeof __get_user argument not 1, 2, 4 or 8")));
 175
 176 /**
 177  * __get_user: - Get a simple variable from user space, with less checking.
 178  * @x:   Variable to store result.
 179  * @ptr: Source address, in user space.
 180  *
 181  * Context: User context only. This function may sleep if pagefaults are
 182  *          enabled.
 183  *
 184  * This macro copies a single simple variable from user space to kernel
 185  * space.  It supports simple types like char and int, but not larger
 186  * data types like structures or arrays.
 187  *
 188  * @ptr must have pointer-to-simple-variable type, and the result of
 189  * dereferencing @ptr must be assignable to @x without a cast.
 190  *
 191  * Returns zero on success, or -EFAULT on error.
 192  * On error, the variable @x is set to zero.
 193  *
 194  * Caller must check the pointer with access_ok() before calling this
 195  * function.
 196  */
 197 #define __get_user(x, ptr)                                              \
 198         ({                                                              \
 199                 int __ret;                                              \
 200                 typeof(x) _x;                                           \
 201                 __chk_user_ptr(ptr);                                    \
 202                 switch (sizeof(*(ptr))) {                               \
 203                 case 1: __get_user_1(_x, ptr, __ret); break;            \
 204                 case 2: __get_user_2(_x, ptr, __ret); break;            \
 205                 case 4: __get_user_4(_x, ptr, __ret); break;            \
 206                 case 8: __get_user_8(_x, ptr, __ret); break;            \
 207                 default: __ret = __get_user_bad(); break;               \
 208                 }                                                       \
 209                 (x) = (typeof(*(ptr))) _x;                              \
 210                 __ret;                                                  \
 211         })
 212
 213 /* Support macros for __put_user(). */
 214
 215 #define __put_user_asm(OP, x, ptr, ret)                 \
 216         asm volatile("1: {" #OP " %1, %2; movei %0, 0 }\n"              \
 217                      ".pushsection .fixup,\"ax\"\n"                     \
 218                      "0: { movei %0, %3; j 9f }\n"                      \
 219                      ".section __ex_table,\"a\"\n"                      \
 220                      _ASM_ALIGN "\n"                                    \
 221                      _ASM_PTR " 1b, 0b\n"                               \
 222                      ".popsection\n"                                    \
 223                      "9:"                                               \
 224                      : "=r" (ret)                                       \
 225                      : "r" (ptr), "r" (x), "i" (-EFAULT))
 226
 227 #ifdef __tilegx__
 228 #define __put_user_1(x, ptr, ret) __put_user_asm(st1, x, ptr, ret)
 229 #define __put_user_2(x, ptr, ret) __put_user_asm(st2, x, ptr, ret)
 230 #define __put_user_4(x, ptr, ret) __put_user_asm(st4, x, ptr, ret)
 231 #define __put_user_8(x, ptr, ret) __put_user_asm(st, x, ptr, ret)
 232 #else
 233 #define __put_user_1(x, ptr, ret) __put_user_asm(sb, x, ptr, ret)
 234 #define __put_user_2(x, ptr, ret) __put_user_asm(sh, x, ptr, ret)
 235 #define __put_user_4(x, ptr, ret) __put_user_asm(sw, x, ptr, ret)
 236 #define __put_user_8(x, ptr, ret)                                       \
 237         ({                                                              \
 238                 u64 __x = (__force __inttype(x))(x);                    \
 239                 int __lo = (int) __x, __hi = (int) (__x >> 32);         \
 240                 asm volatile("1: { sw %1, %2; addi %0, %1, 4 }\n"       \
 241                              "2: { sw %0, %3; movei %0, 0 }\n"          \
 242                              ".pushsection .fixup,\"ax\"\n"             \
 243                              "0: { movei %0, %4; j 9f }\n"              \
 244                              ".section __ex_table,\"a\"\n"              \
 245                              ".align 4\n"                               \
 246                              ".word 1b, 0b\n"                           \
 247                              ".word 2b, 0b\n"                           \
 248                              ".popsection\n"                            \
 249                              "9:"                                       \
 250                              : "=&r" (ret)                              \
 251                              : "r" (ptr), "r" (__lo32(__lo, __hi)),     \
 252                              "r" (__hi32(__lo, __hi)), "i" (-EFAULT));  \
 253         })
 254 #endif
 255
 256 extern int __put_user_bad(void)
 257   __attribute__((warning("sizeof __put_user argument not 1, 2, 4 or 8")));
 258
 259 /**
 260  * __put_user: - Write a simple value into user space, with less checking.
 261  * @x:   Value to copy to user space.
 262  * @ptr: Destination address, in user space.
 263  *
 264  * Context: User context only. This function may sleep if pagefaults are
 265  *          enabled.
 266  *
 267  * This macro copies a single simple value from kernel space to user
 268  * space.  It supports simple types like char and int, but not larger
 269  * data types like structures or arrays.
 270  *
 271  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 272  * to the result of dereferencing @ptr.
 273  *
 274  * Caller must check the pointer with access_ok() before calling this
 275  * function.
 276  *
 277  * Returns zero on success, or -EFAULT on error.
 278  */
 279 #define __put_user(x, ptr)                                              \
 280 ({                                                                      \
 281         int __ret;                                                      \
 282         typeof(*(ptr)) _x = (x);                                        \
 283         __chk_user_ptr(ptr);                                            \
 284         switch (sizeof(*(ptr))) {                                       \
 285         case 1: __put_user_1(_x, ptr, __ret); break;                    \
 286         case 2: __put_user_2(_x, ptr, __ret); break;                    \
 287         case 4: __put_user_4(_x, ptr, __ret); break;                    \
 288         case 8: __put_user_8(_x, ptr, __ret); break;                    \
 289         default: __ret = __put_user_bad(); break;                       \
 290         }                                                               \
 291         __ret;                                                          \
 292 })
 293
 294 /*
 295  * The versions of get_user and put_user without initial underscores
 296  * check the address of their arguments to make sure they are not
 297  * in kernel space.
 298  */
 299 #define put_user(x, ptr)                                                \
 300 ({                                                                      \
 301         __typeof__(*(ptr)) __user *__Pu_addr = (ptr);                   \
 302         access_ok(VERIFY_WRITE, (__Pu_addr), sizeof(*(__Pu_addr))) ?    \
 303                 __put_user((x), (__Pu_addr)) :                          \
 304                 -EFAULT;                                                \
 305 })
 306
 307 #define get_user(x, ptr)                                                \
 308 ({                                                                      \
 309         __typeof__(*(ptr)) const __user *__Gu_addr = (ptr);             \
 310         access_ok(VERIFY_READ, (__Gu_addr), sizeof(*(__Gu_addr))) ?     \
 311                 __get_user((x), (__Gu_addr)) :                          \
 312                 ((x) = 0, -EFAULT);                                     \
 313 })
 314
 315 extern unsigned long __must_check
 316 raw_copy_to_user(void __user *to, const void *from, unsigned long n);
 317 extern unsigned long __must_check
 318 raw_copy_from_user(void *to, const void __user *from, unsigned long n);
 319 #define INLINE_COPY_FROM_USER
 320 #define INLINE_COPY_TO_USER
 321
 322 #ifdef __tilegx__
 323 extern unsigned long raw_copy_in_user(
 324         void __user *to, const void __user *from, unsigned long n);
 325 #endif
 326
 327
 328 extern long strnlen_user(const char __user *str, long n);
 329 extern long strncpy_from_user(char *dst, const char __user *src, long);
 330
 331 /**
 332  * clear_user: - Zero a block of memory in user space.
 333  * @mem:   Destination address, in user space.
 334  * @len:   Number of bytes to zero.
 335  *
 336  * Zero a block of memory in user space.
 337  *
 338  * Returns number of bytes that could not be cleared.
 339  * On success, this will be zero.
 340  */
 341 extern unsigned long clear_user_asm(void __user *mem, unsigned long len);
 342 static inline unsigned long __must_check __clear_user(
 343         void __user *mem, unsigned long len)
 344 {
 345         might_fault();
 346         return clear_user_asm(mem, len);
 347 }
 348 static inline unsigned long __must_check clear_user(
 349         void __user *mem, unsigned long len)
 350 {
 351         if (access_ok(VERIFY_WRITE, mem, len))
 352                 return __clear_user(mem, len);
 353         return len;
 354 }
 355
 356 /**
 357  * flush_user: - Flush a block of memory in user space from cache.
 358  * @mem:   Destination address, in user space.
 359  * @len:   Number of bytes to flush.
 360  *
 361  * Returns number of bytes that could not be flushed.
 362  * On success, this will be zero.
 363  */
 364 extern unsigned long flush_user_asm(void __user *mem, unsigned long len);
 365 static inline unsigned long __must_check __flush_user(
 366         void __user *mem, unsigned long len)
 367 {
 368         int retval;
 369
 370         might_fault();
 371         retval = flush_user_asm(mem, len);
 372         mb_incoherent();
 373         return retval;
 374 }
 375
 376 static inline unsigned long __must_check flush_user(
 377         void __user *mem, unsigned long len)
 378 {
 379         if (access_ok(VERIFY_WRITE, mem, len))
 380                 return __flush_user(mem, len);
 381         return len;
 382 }
 383
 384 /**
 385  * finv_user: - Flush-inval a block of memory in user space from cache.
 386  * @mem:   Destination address, in user space.
 387  * @len:   Number of bytes to invalidate.
 388  *
 389  * Returns number of bytes that could not be flush-invalidated.
 390  * On success, this will be zero.
 391  */
 392 extern unsigned long finv_user_asm(void __user *mem, unsigned long len);
 393 static inline unsigned long __must_check __finv_user(
 394         void __user *mem, unsigned long len)
 395 {
 396         int retval;
 397
 398         might_fault();
 399         retval = finv_user_asm(mem, len);
 400         mb_incoherent();
 401         return retval;
 402 }
 403 static inline unsigned long __must_check finv_user(
 404         void __user *mem, unsigned long len)
 405 {
 406         if (access_ok(VERIFY_WRITE, mem, len))
 407                 return __finv_user(mem, len);
 408         return len;
 409 }
 410
 411 #endif /* _ASM_TILE_UACCESS_H */