arch/ia64/include/asm/uaccess.h

   1 #ifndef _ASM_IA64_UACCESS_H
   2 #define _ASM_IA64_UACCESS_H
   3
   4 /*
   5  * This file defines various macros to transfer memory areas across
   6  * the user/kernel boundary.  This needs to be done carefully because
   7  * this code is executed in kernel mode and uses user-specified
   8  * addresses.  Thus, we need to be careful not to let the user to
   9  * trick us into accessing kernel memory that would normally be
  10  * inaccessible.  This code is also fairly performance sensitive,
  11  * so we want to spend as little time doing safety checks as
  12  * possible.
  13  *
  14  * To make matters a bit more interesting, these macros sometimes also
  15  * called from within the kernel itself, in which case the address
  16  * validity check must be skipped.  The get_fs() macro tells us what
  17  * to do: if get_fs()==USER_DS, checking is performed, if
  18  * get_fs()==KERNEL_DS, checking is bypassed.
  19  *
  20  * Note that even if the memory area specified by the user is in a
  21  * valid address range, it is still possible that we'll get a page
  22  * fault while accessing it.  This is handled by filling out an
  23  * exception handler fixup entry for each instruction that has the
  24  * potential to fault.  When such a fault occurs, the page fault
  25  * handler checks to see whether the faulting instruction has a fixup
  26  * associated and, if so, sets r8 to -EFAULT and clears r9 to 0 and
  27  * then resumes execution at the continuation point.
  28  *
  29  * Based on <asm-alpha/uaccess.h>.
  30  *
  31  * Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co
  32  *      David Mosberger-Tang <davidm@hpl.hp.com>
  33  */
  34
  35 #include <linux/compiler.h>
  36 #include <linux/errno.h>
  37 #include <linux/sched.h>
  38 #include <linux/page-flags.h>
  39 #include <linux/mm.h>
  40
  41 #include <asm/intrinsics.h>
  42 #include <asm/pgtable.h>
  43 #include <asm/io.h>
  44
  45 /*
  46  * For historical reasons, the following macros are grossly misnamed:
  47  */
  48 #define KERNEL_DS       ((mm_segment_t) { ~0UL })               /* cf. access_ok() */
  49 #define USER_DS         ((mm_segment_t) { TASK_SIZE-1 })        /* cf. access_ok() */
  50
  51 #define VERIFY_READ     0
  52 #define VERIFY_WRITE    1
  53
  54 #define get_ds()  (KERNEL_DS)
  55 #define get_fs()  (current_thread_info()->addr_limit)
  56 #define set_fs(x) (current_thread_info()->addr_limit = (x))
  57
  58 #define segment_eq(a, b)        ((a).seg == (b).seg)
  59
  60 /*
  61  * When accessing user memory, we need to make sure the entire area really is in
  62  * user-level space.  In order to do this efficiently, we make sure that the page at
  63  * address TASK_SIZE is never valid.  We also need to make sure that the address doesn't
  64  * point inside the virtually mapped linear page table.
  65  */
  66 #define __access_ok(addr, size, segment)                                                \
  67 ({                                                                                      \
  68         __chk_user_ptr(addr);                                                           \
  69         (likely((unsigned long) (addr) <= (segment).seg)                                \
  70          && ((segment).seg == KERNEL_DS.seg                                             \
  71              || likely(REGION_OFFSET((unsigned long) (addr)) < RGN_MAP_LIMIT)));        \
  72 })
  73 #define access_ok(type, addr, size)     __access_ok((addr), (size), get_fs())
  74
  75 /*
  76  * These are the main single-value transfer routines.  They automatically
  77  * use the right size if we just have the right pointer type.
  78  *
  79  * Careful to not
  80  * (a) re-use the arguments for side effects (sizeof/typeof is ok)
  81  * (b) require any knowledge of processes at this stage
  82  */
  83 #define put_user(x, ptr)        __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)), get_fs())
  84 #define get_user(x, ptr)        __get_user_check((x), (ptr), sizeof(*(ptr)), get_fs())
  85
  86 /*
  87  * The "__xxx" versions do not do address space checking, useful when
  88  * doing multiple accesses to the same area (the programmer has to do the
  89  * checks by hand with "access_ok()")
  90  */
  91 #define __put_user(x, ptr)      __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
  92 #define __get_user(x, ptr)      __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  93
  94 extern long __put_user_unaligned_unknown (void);
  95
  96 #define __put_user_unaligned(x, ptr)                                                            \
  97 ({                                                                                              \
  98         long __ret;                                                                             \
  99         switch (sizeof(*(ptr))) {                                                               \
 100                 case 1: __ret = __put_user((x), (ptr)); break;                                  \
 101                 case 2: __ret = (__put_user((x), (u8 __user *)(ptr)))                           \
 102                         | (__put_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;              \
 103                 case 4: __ret = (__put_user((x), (u16 __user *)(ptr)))                          \
 104                         | (__put_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;            \
 105                 case 8: __ret = (__put_user((x), (u32 __user *)(ptr)))                          \
 106                         | (__put_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;            \
 107                 default: __ret = __put_user_unaligned_unknown();                                \
 108         }                                                                                       \
 109         __ret;                                                                                  \
 110 })
 111
 112 extern long __get_user_unaligned_unknown (void);
 113
 114 #define __get_user_unaligned(x, ptr)                                                            \
 115 ({                                                                                              \
 116         long __ret;                                                                             \
 117         switch (sizeof(*(ptr))) {                                                               \
 118                 case 1: __ret = __get_user((x), (ptr)); break;                                  \
 119                 case 2: __ret = (__get_user((x), (u8 __user *)(ptr)))                           \
 120                         | (__get_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;              \
 121                 case 4: __ret = (__get_user((x), (u16 __user *)(ptr)))                          \
 122                         | (__get_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;            \
 123                 case 8: __ret = (__get_user((x), (u32 __user *)(ptr)))                          \
 124                         | (__get_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;            \
 125                 default: __ret = __get_user_unaligned_unknown();                                \
 126         }                                                                                       \
 127         __ret;                                                                                  \
 128 })
 129
 130 #ifdef ASM_SUPPORTED
 131   struct __large_struct { unsigned long buf[100]; };
 132 # define __m(x) (*(struct __large_struct __user *)(x))
 133
 134 /* We need to declare the __ex_table section before we can use it in .xdata.  */
 135 asm (".section \"__ex_table\", \"a\"\n\t.previous");
 136
 137 # define __get_user_size(val, addr, n, err)                                                     \
 138 do {                                                                                            \
 139         register long __gu_r8 asm ("r8") = 0;                                                   \
 140         register long __gu_r9 asm ("r9");                                                       \
 141         asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n"     \
 142              "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n"                                         \
 143              "[1:]"                                                                             \
 144              : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8));                    \
 145         (err) = __gu_r8;                                                                        \
 146         (val) = __gu_r9;                                                                        \
 147 } while (0)
 148
 149 /*
 150  * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it.  This
 151  * is because they do not write to any memory gcc knows about, so there are no aliasing
 152  * issues.
 153  */
 154 # define __put_user_size(val, addr, n, err)                                                     \
 155 do {                                                                                            \
 156         register long __pu_r8 asm ("r8") = 0;                                                   \
 157         asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \
 158                       "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n"                                  \
 159                       "[1:]"                                                                    \
 160                       : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8));               \
 161         (err) = __pu_r8;                                                                        \
 162 } while (0)
 163
 164 #else /* !ASM_SUPPORTED */
 165 # define RELOC_TYPE     2       /* ip-rel */
 166 # define __get_user_size(val, addr, n, err)                             \
 167 do {                                                                    \
 168         __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE);   \
 169         (err) = ia64_getreg(_IA64_REG_R8);                              \
 170         (val) = ia64_getreg(_IA64_REG_R9);                              \
 171 } while (0)
 172 # define __put_user_size(val, addr, n, err)                                                     \
 173 do {                                                                                            \
 174         __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, (unsigned long) (val));    \
 175         (err) = ia64_getreg(_IA64_REG_R8);                                                      \
 176 } while (0)
 177 #endif /* !ASM_SUPPORTED */
 178
 179 extern void __get_user_unknown (void);
 180
 181 /*
 182  * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
 183  * could clobber r8 and r9 (among others).  Thus, be careful not to evaluate it while
 184  * using r8/r9.
 185  */
 186 #define __do_get_user(check, x, ptr, size, segment)                                     \
 187 ({                                                                                      \
 188         const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);                              \
 189         __typeof__ (size) __gu_size = (size);                                           \
 190         long __gu_err = -EFAULT;                                                        \
 191         unsigned long __gu_val = 0;                                                     \
 192         if (!check || __access_ok(__gu_ptr, size, segment))                             \
 193                 switch (__gu_size) {                                                    \
 194                       case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break;  \
 195                       case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break;  \
 196                       case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break;  \
 197                       case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break;  \
 198                       default: __get_user_unknown(); break;                             \
 199                 }                                                                       \
 200         (x) = (__typeof__(*(__gu_ptr))) __gu_val;                                       \
 201         __gu_err;                                                                       \
 202 })
 203
 204 #define __get_user_nocheck(x, ptr, size)        __do_get_user(0, x, ptr, size, KERNEL_DS)
 205 #define __get_user_check(x, ptr, size, segment) __do_get_user(1, x, ptr, size, segment)
 206
 207 extern void __put_user_unknown (void);
 208
 209 /*
 210  * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
 211  * could clobber r8 (among others).  Thus, be careful not to evaluate them while using r8.
 212  */
 213 #define __do_put_user(check, x, ptr, size, segment)                                     \
 214 ({                                                                                      \
 215         __typeof__ (x) __pu_x = (x);                                                    \
 216         __typeof__ (*(ptr)) __user *__pu_ptr = (ptr);                                   \
 217         __typeof__ (size) __pu_size = (size);                                           \
 218         long __pu_err = -EFAULT;                                                        \
 219                                                                                         \
 220         if (!check || __access_ok(__pu_ptr, __pu_size, segment))                        \
 221                 switch (__pu_size) {                                                    \
 222                       case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break;    \
 223                       case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break;    \
 224                       case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break;    \
 225                       case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break;    \
 226                       default: __put_user_unknown(); break;                             \
 227                 }                                                                       \
 228         __pu_err;                                                                       \
 229 })
 230
 231 #define __put_user_nocheck(x, ptr, size)        __do_put_user(0, x, ptr, size, KERNEL_DS)
 232 #define __put_user_check(x, ptr, size, segment) __do_put_user(1, x, ptr, size, segment)
 233
 234 /*
 235  * Complex access routines
 236  */
 237 extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
 238                                                unsigned long count);
 239
 240 static inline unsigned long
 241 __copy_to_user (void __user *to, const void *from, unsigned long count)
 242 {
 243         return __copy_user(to, (__force void __user *) from, count);
 244 }
 245
 246 static inline unsigned long
 247 __copy_from_user (void *to, const void __user *from, unsigned long count)
 248 {
 249         return __copy_user((__force void __user *) to, from, count);
 250 }
 251
 252 #define __copy_to_user_inatomic         __copy_to_user
 253 #define __copy_from_user_inatomic       __copy_from_user
 254 #define copy_to_user(to, from, n)                                                       \
 255 ({                                                                                      \
 256         void __user *__cu_to = (to);                                                    \
 257         const void *__cu_from = (from);                                                 \
 258         long __cu_len = (n);                                                            \
 259                                                                                         \
 260         if (__access_ok(__cu_to, __cu_len, get_fs()))                                   \
 261                 __cu_len = __copy_user(__cu_to, (__force void __user *) __cu_from, __cu_len);   \
 262         __cu_len;                                                                       \
 263 })
 264
 265 #define copy_from_user(to, from, n)                                                     \
 266 ({                                                                                      \
 267         void *__cu_to = (to);                                                           \
 268         const void __user *__cu_from = (from);                                          \
 269         long __cu_len = (n);                                                            \
 270                                                                                         \
 271         __chk_user_ptr(__cu_from);                                                      \
 272         if (__access_ok(__cu_from, __cu_len, get_fs()))                                 \
 273                 __cu_len = __copy_user((__force void __user *) __cu_to, __cu_from, __cu_len);   \
 274         __cu_len;                                                                       \
 275 })
 276
 277 #define __copy_in_user(to, from, size)  __copy_user((to), (from), (size))
 278
 279 static inline unsigned long
 280 copy_in_user (void __user *to, const void __user *from, unsigned long n)
 281 {
 282         if (likely(access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n)))
 283                 n = __copy_user(to, from, n);
 284         return n;
 285 }
 286
 287 extern unsigned long __do_clear_user (void __user *, unsigned long);
 288
 289 #define __clear_user(to, n)             __do_clear_user(to, n)
 290
 291 #define clear_user(to, n)                                       \
 292 ({                                                              \
 293         unsigned long __cu_len = (n);                           \
 294         if (__access_ok(to, __cu_len, get_fs()))                \
 295                 __cu_len = __do_clear_user(to, __cu_len);       \
 296         __cu_len;                                               \
 297 })
 298
 299
 300 /*
 301  * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
 302  * strlen.
 303  */
 304 extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);
 305
 306 #define strncpy_from_user(to, from, n)                                  \
 307 ({                                                                      \
 308         const char __user * __sfu_from = (from);                        \
 309         long __sfu_ret = -EFAULT;                                       \
 310         if (__access_ok(__sfu_from, 0, get_fs()))                       \
 311                 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
 312         __sfu_ret;                                                      \
 313 })
 314
 315 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 316 extern unsigned long __strlen_user (const char __user *);
 317
 318 #define strlen_user(str)                                \
 319 ({                                                      \
 320         const char __user *__su_str = (str);            \
 321         unsigned long __su_ret = 0;                     \
 322         if (__access_ok(__su_str, 0, get_fs()))         \
 323                 __su_ret = __strlen_user(__su_str);     \
 324         __su_ret;                                       \
 325 })
 326
 327 /*
 328  * Returns: 0 if exception before NUL or reaching the supplied limit
 329  * (N), a value greater than N if the limit would be exceeded, else
 330  * strlen.
 331  */
 332 extern unsigned long __strnlen_user (const char __user *, long);
 333
 334 #define strnlen_user(str, len)                                  \
 335 ({                                                              \
 336         const char __user *__su_str = (str);                    \
 337         unsigned long __su_ret = 0;                             \
 338         if (__access_ok(__su_str, 0, get_fs()))                 \
 339                 __su_ret = __strnlen_user(__su_str, len);       \
 340         __su_ret;                                               \
 341 })
 342
 343 /* Generic code can't deal with the location-relative format that we use for compactness.  */
 344 #define ARCH_HAS_SORT_EXTABLE
 345 #define ARCH_HAS_SEARCH_EXTABLE
 346
 347 struct exception_table_entry {
 348         int addr;       /* location-relative address of insn this fixup is for */
 349         int cont;       /* location-relative continuation addr.; if bit 2 is set, r9 is set to 0 */
 350 };
 351
 352 extern void ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e);
 353 extern const struct exception_table_entry *search_exception_tables (unsigned long addr);
 354
 355 static inline int
 356 ia64_done_with_exception (struct pt_regs *regs)
 357 {
 358         const struct exception_table_entry *e;
 359         e = search_exception_tables(regs->cr_iip + ia64_psr(regs)->ri);
 360         if (e) {
 361                 ia64_handle_exception(regs, e);
 362                 return 1;
 363         }
 364         return 0;
 365 }
 366
 367 #define ARCH_HAS_TRANSLATE_MEM_PTR      1
 368 static __inline__ char *
 369 xlate_dev_mem_ptr (unsigned long p)
 370 {
 371         struct page *page;
 372         char * ptr;
 373
 374         page = pfn_to_page(p >> PAGE_SHIFT);
 375         if (PageUncached(page))
 376                 ptr = (char *)p + __IA64_UNCACHED_OFFSET;
 377         else
 378                 ptr = __va(p);
 379
 380         return ptr;
 381 }
 382
 383 /*
 384  * Convert a virtual cached kernel memory pointer to an uncached pointer
 385  */
 386 static __inline__ char *
 387 xlate_dev_kmem_ptr (char * p)
 388 {
 389         struct page *page;
 390         char * ptr;
 391
 392         page = virt_to_page((unsigned long)p);
 393         if (PageUncached(page))
 394                 ptr = (char *)__pa(p) + __IA64_UNCACHED_OFFSET;
 395         else
 396                 ptr = p;
 397
 398         return ptr;
 399 }
 400
 401 #endif /* _ASM_IA64_UACCESS_H */