linux/arch/cris/include/asm/uaccess.h
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   1/* 
   2 * Authors:    Bjorn Wesen (bjornw@axis.com)
   3 *             Hans-Peter Nilsson (hp@axis.com)
   4 */
   5
   6/* Asm:s have been tweaked (within the domain of correctness) to give
   7   satisfactory results for "gcc version 2.96 20000427 (experimental)".
   8
   9   Check regularly...
  10
  11   Register $r9 is chosen for temporaries, being a call-clobbered register
  12   first in line to be used (notably for local blocks), not colliding with
  13   parameter registers.  */
  14
  15#ifndef _CRIS_UACCESS_H
  16#define _CRIS_UACCESS_H
  17
  18#ifndef __ASSEMBLY__
  19#include <linux/sched.h>
  20#include <linux/errno.h>
  21#include <asm/processor.h>
  22#include <asm/page.h>
  23
  24#define VERIFY_READ     0
  25#define VERIFY_WRITE    1
  26
  27/*
  28 * The fs value determines whether argument validity checking should be
  29 * performed or not.  If get_fs() == USER_DS, checking is performed, with
  30 * get_fs() == KERNEL_DS, checking is bypassed.
  31 *
  32 * For historical reasons, these macros are grossly misnamed.
  33 */
  34
  35#define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  36
  37/* addr_limit is the maximum accessible address for the task. we misuse
  38 * the KERNEL_DS and USER_DS values to both assign and compare the 
  39 * addr_limit values through the equally misnamed get/set_fs macros.
  40 * (see above)
  41 */
  42
  43#define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
  44#define USER_DS         MAKE_MM_SEG(TASK_SIZE)
  45
  46#define get_ds()        (KERNEL_DS)
  47#define get_fs()        (current_thread_info()->addr_limit)
  48#define set_fs(x)       (current_thread_info()->addr_limit = (x))
  49
  50#define segment_eq(a,b) ((a).seg == (b).seg)
  51
  52#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
  53#define __user_ok(addr,size) (((size) <= TASK_SIZE)&&((addr) <= TASK_SIZE-(size)))
  54#define __access_ok(addr,size) (__kernel_ok || __user_ok((addr),(size)))
  55#define access_ok(type,addr,size) __access_ok((unsigned long)(addr),(size))
  56
  57#include <arch/uaccess.h>
  58
  59/*
  60 * The exception table consists of pairs of addresses: the first is the
  61 * address of an instruction that is allowed to fault, and the second is
  62 * the address at which the program should continue.  No registers are
  63 * modified, so it is entirely up to the continuation code to figure out
  64 * what to do.
  65 *
  66 * All the routines below use bits of fixup code that are out of line
  67 * with the main instruction path.  This means when everything is well,
  68 * we don't even have to jump over them.  Further, they do not intrude
  69 * on our cache or tlb entries.
  70 */
  71
  72struct exception_table_entry
  73{
  74        unsigned long insn, fixup;
  75};
  76
  77/*
  78 * These are the main single-value transfer routines.  They automatically
  79 * use the right size if we just have the right pointer type.
  80 *
  81 * This gets kind of ugly. We want to return _two_ values in "get_user()"
  82 * and yet we don't want to do any pointers, because that is too much
  83 * of a performance impact. Thus we have a few rather ugly macros here,
  84 * and hide all the ugliness from the user.
  85 *
  86 * The "__xxx" versions of the user access functions are versions that
  87 * do not verify the address space, that must have been done previously
  88 * with a separate "access_ok()" call (this is used when we do multiple
  89 * accesses to the same area of user memory).
  90 *
  91 * As we use the same address space for kernel and user data on
  92 * CRIS, we can just do these as direct assignments.  (Of course, the
  93 * exception handling means that it's no longer "just"...)
  94 */
  95#define get_user(x,ptr) \
  96  __get_user_check((x),(ptr),sizeof(*(ptr)))
  97#define put_user(x,ptr) \
  98  __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
  99
 100#define __get_user(x,ptr) \
 101  __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
 102#define __put_user(x,ptr) \
 103  __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 104
 105extern long __put_user_bad(void);
 106
 107#define __put_user_size(x,ptr,size,retval)                      \
 108do {                                                            \
 109        retval = 0;                                             \
 110        switch (size) {                                         \
 111          case 1: __put_user_asm(x,ptr,retval,"move.b"); break; \
 112          case 2: __put_user_asm(x,ptr,retval,"move.w"); break; \
 113          case 4: __put_user_asm(x,ptr,retval,"move.d"); break; \
 114          case 8: __put_user_asm_64(x,ptr,retval); break;       \
 115          default: __put_user_bad();                            \
 116        }                                                       \
 117} while (0)
 118
 119#define __get_user_size(x,ptr,size,retval)                      \
 120do {                                                            \
 121        retval = 0;                                             \
 122        switch (size) {                                         \
 123          case 1: __get_user_asm(x,ptr,retval,"move.b"); break; \
 124          case 2: __get_user_asm(x,ptr,retval,"move.w"); break; \
 125          case 4: __get_user_asm(x,ptr,retval,"move.d"); break; \
 126          case 8: __get_user_asm_64(x,ptr,retval); break;       \
 127          default: (x) = __get_user_bad();                      \
 128        }                                                       \
 129} while (0)
 130
 131#define __put_user_nocheck(x,ptr,size)                  \
 132({                                                      \
 133        long __pu_err;                                  \
 134        __put_user_size((x),(ptr),(size),__pu_err);     \
 135        __pu_err;                                       \
 136})
 137
 138#define __put_user_check(x,ptr,size)                            \
 139({                                                              \
 140        long __pu_err = -EFAULT;                                \
 141        __typeof__(*(ptr)) *__pu_addr = (ptr);                  \
 142        if (access_ok(VERIFY_WRITE,__pu_addr,size))             \
 143                __put_user_size((x),__pu_addr,(size),__pu_err); \
 144        __pu_err;                                               \
 145})
 146
 147struct __large_struct { unsigned long buf[100]; };
 148#define __m(x) (*(struct __large_struct *)(x))
 149
 150
 151
 152#define __get_user_nocheck(x,ptr,size)                          \
 153({                                                              \
 154        long __gu_err, __gu_val;                                \
 155        __get_user_size(__gu_val,(ptr),(size),__gu_err);        \
 156        (x) = (__typeof__(*(ptr)))__gu_val;                     \
 157        __gu_err;                                               \
 158})
 159
 160#define __get_user_check(x,ptr,size)                                    \
 161({                                                                      \
 162        long __gu_err = -EFAULT, __gu_val = 0;                          \
 163        const __typeof__(*(ptr)) *__gu_addr = (ptr);                    \
 164        if (access_ok(VERIFY_READ,__gu_addr,size))                      \
 165                __get_user_size(__gu_val,__gu_addr,(size),__gu_err);    \
 166        (x) = (__typeof__(*(ptr)))__gu_val;                             \
 167        __gu_err;                                                       \
 168})
 169
 170extern long __get_user_bad(void);
 171
 172/* More complex functions.  Most are inline, but some call functions that
 173   live in lib/usercopy.c  */
 174
 175extern unsigned long __copy_user(void __user *to, const void *from, unsigned long n);
 176extern unsigned long __copy_user_zeroing(void *to, const void __user *from, unsigned long n);
 177extern unsigned long __do_clear_user(void __user *to, unsigned long n);
 178
 179static inline unsigned long
 180__generic_copy_to_user(void __user *to, const void *from, unsigned long n)
 181{
 182        if (access_ok(VERIFY_WRITE, to, n))
 183                return __copy_user(to,from,n);
 184        return n;
 185}
 186
 187static inline unsigned long
 188__generic_copy_from_user(void *to, const void __user *from, unsigned long n)
 189{
 190        if (access_ok(VERIFY_READ, from, n))
 191                return __copy_user_zeroing(to,from,n);
 192        return n;
 193}
 194
 195static inline unsigned long
 196__generic_clear_user(void __user *to, unsigned long n)
 197{
 198        if (access_ok(VERIFY_WRITE, to, n))
 199                return __do_clear_user(to,n);
 200        return n;
 201}
 202
 203static inline long
 204__strncpy_from_user(char *dst, const char __user *src, long count)
 205{
 206        return __do_strncpy_from_user(dst, src, count);
 207}
 208
 209static inline long
 210strncpy_from_user(char *dst, const char __user *src, long count)
 211{
 212        long res = -EFAULT;
 213        if (access_ok(VERIFY_READ, src, 1))
 214                res = __do_strncpy_from_user(dst, src, count);
 215        return res;
 216}
 217
 218
 219/* Note that these expand awfully if made into switch constructs, so
 220   don't do that.  */
 221
 222static inline unsigned long
 223__constant_copy_from_user(void *to, const void __user *from, unsigned long n)
 224{
 225        unsigned long ret = 0;
 226        if (n == 0)
 227                ;
 228        else if (n == 1)
 229                __asm_copy_from_user_1(to, from, ret);
 230        else if (n == 2)
 231                __asm_copy_from_user_2(to, from, ret);
 232        else if (n == 3)
 233                __asm_copy_from_user_3(to, from, ret);
 234        else if (n == 4)
 235                __asm_copy_from_user_4(to, from, ret);
 236        else if (n == 5)
 237                __asm_copy_from_user_5(to, from, ret);
 238        else if (n == 6)
 239                __asm_copy_from_user_6(to, from, ret);
 240        else if (n == 7)
 241                __asm_copy_from_user_7(to, from, ret);
 242        else if (n == 8)
 243                __asm_copy_from_user_8(to, from, ret);
 244        else if (n == 9)
 245                __asm_copy_from_user_9(to, from, ret);
 246        else if (n == 10)
 247                __asm_copy_from_user_10(to, from, ret);
 248        else if (n == 11)
 249                __asm_copy_from_user_11(to, from, ret);
 250        else if (n == 12)
 251                __asm_copy_from_user_12(to, from, ret);
 252        else if (n == 13)
 253                __asm_copy_from_user_13(to, from, ret);
 254        else if (n == 14)
 255                __asm_copy_from_user_14(to, from, ret);
 256        else if (n == 15)
 257                __asm_copy_from_user_15(to, from, ret);
 258        else if (n == 16)
 259                __asm_copy_from_user_16(to, from, ret);
 260        else if (n == 20)
 261                __asm_copy_from_user_20(to, from, ret);
 262        else if (n == 24)
 263                __asm_copy_from_user_24(to, from, ret);
 264        else
 265                ret = __generic_copy_from_user(to, from, n);
 266
 267        return ret;
 268}
 269
 270/* Ditto, don't make a switch out of this.  */
 271
 272static inline unsigned long
 273__constant_copy_to_user(void __user *to, const void *from, unsigned long n)
 274{
 275        unsigned long ret = 0;
 276        if (n == 0)
 277                ;
 278        else if (n == 1)
 279                __asm_copy_to_user_1(to, from, ret);
 280        else if (n == 2)
 281                __asm_copy_to_user_2(to, from, ret);
 282        else if (n == 3)
 283                __asm_copy_to_user_3(to, from, ret);
 284        else if (n == 4)
 285                __asm_copy_to_user_4(to, from, ret);
 286        else if (n == 5)
 287                __asm_copy_to_user_5(to, from, ret);
 288        else if (n == 6)
 289                __asm_copy_to_user_6(to, from, ret);
 290        else if (n == 7)
 291                __asm_copy_to_user_7(to, from, ret);
 292        else if (n == 8)
 293                __asm_copy_to_user_8(to, from, ret);
 294        else if (n == 9)
 295                __asm_copy_to_user_9(to, from, ret);
 296        else if (n == 10)
 297                __asm_copy_to_user_10(to, from, ret);
 298        else if (n == 11)
 299                __asm_copy_to_user_11(to, from, ret);
 300        else if (n == 12)
 301                __asm_copy_to_user_12(to, from, ret);
 302        else if (n == 13)
 303                __asm_copy_to_user_13(to, from, ret);
 304        else if (n == 14)
 305                __asm_copy_to_user_14(to, from, ret);
 306        else if (n == 15)
 307                __asm_copy_to_user_15(to, from, ret);
 308        else if (n == 16)
 309                __asm_copy_to_user_16(to, from, ret);
 310        else if (n == 20)
 311                __asm_copy_to_user_20(to, from, ret);
 312        else if (n == 24)
 313                __asm_copy_to_user_24(to, from, ret);
 314        else
 315                ret = __generic_copy_to_user(to, from, n);
 316
 317        return ret;
 318}
 319
 320/* No switch, please.  */
 321
 322static inline unsigned long
 323__constant_clear_user(void __user *to, unsigned long n)
 324{
 325        unsigned long ret = 0;
 326        if (n == 0)
 327                ;
 328        else if (n == 1)
 329                __asm_clear_1(to, ret);
 330        else if (n == 2)
 331                __asm_clear_2(to, ret);
 332        else if (n == 3)
 333                __asm_clear_3(to, ret);
 334        else if (n == 4)
 335                __asm_clear_4(to, ret);
 336        else if (n == 8)
 337                __asm_clear_8(to, ret);
 338        else if (n == 12)
 339                __asm_clear_12(to, ret);
 340        else if (n == 16)
 341                __asm_clear_16(to, ret);
 342        else if (n == 20)
 343                __asm_clear_20(to, ret);
 344        else if (n == 24)
 345                __asm_clear_24(to, ret);
 346        else
 347                ret = __generic_clear_user(to, n);
 348
 349        return ret;
 350}
 351
 352
 353#define clear_user(to, n)                       \
 354(__builtin_constant_p(n) ?                      \
 355 __constant_clear_user(to, n) :                 \
 356 __generic_clear_user(to, n))
 357
 358#define copy_from_user(to, from, n)             \
 359(__builtin_constant_p(n) ?                      \
 360 __constant_copy_from_user(to, from, n) :       \
 361 __generic_copy_from_user(to, from, n))
 362
 363#define copy_to_user(to, from, n)               \
 364(__builtin_constant_p(n) ?                      \
 365 __constant_copy_to_user(to, from, n) :         \
 366 __generic_copy_to_user(to, from, n))
 367
 368/* We let the __ versions of copy_from/to_user inline, because they're often
 369 * used in fast paths and have only a small space overhead.
 370 */
 371
 372static inline unsigned long
 373__generic_copy_from_user_nocheck(void *to, const void __user *from,
 374                                 unsigned long n)
 375{
 376        return __copy_user_zeroing(to,from,n);
 377}
 378
 379static inline unsigned long
 380__generic_copy_to_user_nocheck(void __user *to, const void *from,
 381                               unsigned long n)
 382{
 383        return __copy_user(to,from,n);
 384}
 385
 386static inline unsigned long
 387__generic_clear_user_nocheck(void __user *to, unsigned long n)
 388{
 389        return __do_clear_user(to,n);
 390}
 391
 392/* without checking */
 393
 394#define __copy_to_user(to,from,n)   __generic_copy_to_user_nocheck((to),(from),(n))
 395#define __copy_from_user(to,from,n) __generic_copy_from_user_nocheck((to),(from),(n))
 396#define __copy_to_user_inatomic __copy_to_user
 397#define __copy_from_user_inatomic __copy_from_user
 398#define __clear_user(to,n) __generic_clear_user_nocheck((to),(n))
 399
 400#define strlen_user(str)        strnlen_user((str), 0x7ffffffe)
 401
 402#endif  /* __ASSEMBLY__ */
 403
 404#endif  /* _CRIS_UACCESS_H */
 405
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