include/asm-ia64/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 /* this function will go away soon - use access_ok() instead */
  76 static inline int __deprecated
  77 verify_area (int type, const void __user *addr, unsigned long size)
  78 {
  79         return access_ok(type, addr, size) ? 0 : -EFAULT;
  80 }
  81
  82 /*
  83  * These are the main single-value transfer routines.  They automatically
  84  * use the right size if we just have the right pointer type.
  85  *
  86  * Careful to not
  87  * (a) re-use the arguments for side effects (sizeof/typeof is ok)
  88  * (b) require any knowledge of processes at this stage
  89  */
  90 #define put_user(x, ptr)        __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)), get_fs())
  91 #define get_user(x, ptr)        __get_user_check((x), (ptr), sizeof(*(ptr)), get_fs())
  92
  93 /*
  94  * The "__xxx" versions do not do address space checking, useful when
  95  * doing multiple accesses to the same area (the programmer has to do the
  96  * checks by hand with "access_ok()")
  97  */
  98 #define __put_user(x, ptr)      __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
  99 #define __get_user(x, ptr)      __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 100
 101 extern long __put_user_unaligned_unknown (void);
 102
 103 #define __put_user_unaligned(x, ptr)                                                            \
 104 ({                                                                                              \
 105         long __ret;                                                                             \
 106         switch (sizeof(*(ptr))) {                                                               \
 107                 case 1: __ret = __put_user((x), (ptr)); break;                                  \
 108                 case 2: __ret = (__put_user((x), (u8 __user *)(ptr)))                           \
 109                         | (__put_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;              \
 110                 case 4: __ret = (__put_user((x), (u16 __user *)(ptr)))                          \
 111                         | (__put_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;            \
 112                 case 8: __ret = (__put_user((x), (u32 __user *)(ptr)))                          \
 113                         | (__put_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;            \
 114                 default: __ret = __put_user_unaligned_unknown();                                \
 115         }                                                                                       \
 116         __ret;                                                                                  \
 117 })
 118
 119 extern long __get_user_unaligned_unknown (void);
 120
 121 #define __get_user_unaligned(x, ptr)                                                            \
 122 ({                                                                                              \
 123         long __ret;                                                                             \
 124         switch (sizeof(*(ptr))) {                                                               \
 125                 case 1: __ret = __get_user((x), (ptr)); break;                                  \
 126                 case 2: __ret = (__get_user((x), (u8 __user *)(ptr)))                           \
 127                         | (__get_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;              \
 128                 case 4: __ret = (__get_user((x), (u16 __user *)(ptr)))                          \
 129                         | (__get_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;            \
 130                 case 8: __ret = (__get_user((x), (u32 __user *)(ptr)))                          \
 131                         | (__get_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;            \
 132                 default: __ret = __get_user_unaligned_unknown();                                \
 133         }                                                                                       \
 134         __ret;                                                                                  \
 135 })
 136
 137 #ifdef ASM_SUPPORTED
 138   struct __large_struct { unsigned long buf[100]; };
 139 # define __m(x) (*(struct __large_struct __user *)(x))
 140
 141 /* We need to declare the __ex_table section before we can use it in .xdata.  */
 142 asm (".section \"__ex_table\", \"a\"\n\t.previous");
 143
 144 # define __get_user_size(val, addr, n, err)                                                     \
 145 do {                                                                                            \
 146         register long __gu_r8 asm ("r8") = 0;                                                   \
 147         register long __gu_r9 asm ("r9");                                                       \
 148         asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n"     \
 149              "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n"                                         \
 150              "[1:]"                                                                             \
 151              : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8));                    \
 152         (err) = __gu_r8;                                                                        \
 153         (val) = __gu_r9;                                                                        \
 154 } while (0)
 155
 156 /*
 157  * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it.  This
 158  * is because they do not write to any memory gcc knows about, so there are no aliasing
 159  * issues.
 160  */
 161 # define __put_user_size(val, addr, n, err)                                                     \
 162 do {                                                                                            \
 163         register long __pu_r8 asm ("r8") = 0;                                                   \
 164         asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \
 165                       "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n"                                  \
 166                       "[1:]"                                                                    \
 167                       : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8));               \
 168         (err) = __pu_r8;                                                                        \
 169 } while (0)
 170
 171 #else /* !ASM_SUPPORTED */
 172 # define RELOC_TYPE     2       /* ip-rel */
 173 # define __get_user_size(val, addr, n, err)                             \
 174 do {                                                                    \
 175         __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE);   \
 176         (err) = ia64_getreg(_IA64_REG_R8);                              \
 177         (val) = ia64_getreg(_IA64_REG_R9);                              \
 178 } while (0)
 179 # define __put_user_size(val, addr, n, err)                                                     \
 180 do {                                                                                            \
 181         __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, (unsigned long) (val));    \
 182         (err) = ia64_getreg(_IA64_REG_R8);                                                      \
 183 } while (0)
 184 #endif /* !ASM_SUPPORTED */
 185
 186 extern void __get_user_unknown (void);
 187
 188 /*
 189  * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
 190  * could clobber r8 and r9 (among others).  Thus, be careful not to evaluate it while
 191  * using r8/r9.
 192  */
 193 #define __do_get_user(check, x, ptr, size, segment)                                     \
 194 ({                                                                                      \
 195         const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);                              \
 196         __typeof__ (size) __gu_size = (size);                                           \
 197         long __gu_err = -EFAULT, __gu_val = 0;                                          \
 198                                                                                         \
 199         if (!check || __access_ok(__gu_ptr, size, segment))                             \
 200                 switch (__gu_size) {                                                    \
 201                       case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break;  \
 202                       case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break;  \
 203                       case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break;  \
 204                       case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break;  \
 205                       default: __get_user_unknown(); break;                             \
 206                 }                                                                       \
 207         (x) = (__typeof__(*(__gu_ptr))) __gu_val;                                       \
 208         __gu_err;                                                                       \
 209 })
 210
 211 #define __get_user_nocheck(x, ptr, size)        __do_get_user(0, x, ptr, size, KERNEL_DS)
 212 #define __get_user_check(x, ptr, size, segment) __do_get_user(1, x, ptr, size, segment)
 213
 214 extern void __put_user_unknown (void);
 215
 216 /*
 217  * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
 218  * could clobber r8 (among others).  Thus, be careful not to evaluate them while using r8.
 219  */
 220 #define __do_put_user(check, x, ptr, size, segment)                                     \
 221 ({                                                                                      \
 222         __typeof__ (x) __pu_x = (x);                                                    \
 223         __typeof__ (*(ptr)) __user *__pu_ptr = (ptr);                                   \
 224         __typeof__ (size) __pu_size = (size);                                           \
 225         long __pu_err = -EFAULT;                                                        \
 226                                                                                         \
 227         if (!check || __access_ok(__pu_ptr, __pu_size, segment))                        \
 228                 switch (__pu_size) {                                                    \
 229                       case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break;    \
 230                       case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break;    \
 231                       case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break;    \
 232                       case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break;    \
 233                       default: __put_user_unknown(); break;                             \
 234                 }                                                                       \
 235         __pu_err;                                                                       \
 236 })
 237
 238 #define __put_user_nocheck(x, ptr, size)        __do_put_user(0, x, ptr, size, KERNEL_DS)
 239 #define __put_user_check(x, ptr, size, segment) __do_put_user(1, x, ptr, size, segment)
 240
 241 /*
 242  * Complex access routines
 243  */
 244 extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
 245                                                unsigned long count);
 246
 247 static inline unsigned long
 248 __copy_to_user (void __user *to, const void *from, unsigned long count)
 249 {
 250         return __copy_user(to, (void __user *) from, count);
 251 }
 252
 253 static inline unsigned long
 254 __copy_from_user (void *to, const void __user *from, unsigned long count)
 255 {
 256         return __copy_user((void __user *) to, from, count);
 257 }
 258
 259 #define __copy_to_user_inatomic         __copy_to_user
 260 #define __copy_from_user_inatomic       __copy_from_user
 261 #define copy_to_user(to, from, n)                                                       \
 262 ({                                                                                      \
 263         void __user *__cu_to = (to);                                                    \
 264         const void *__cu_from = (from);                                                 \
 265         long __cu_len = (n);                                                            \
 266                                                                                         \
 267         if (__access_ok(__cu_to, __cu_len, get_fs()))                                   \
 268                 __cu_len = __copy_user(__cu_to, (void __user *) __cu_from, __cu_len);   \
 269         __cu_len;                                                                       \
 270 })
 271
 272 #define copy_from_user(to, from, n)                                                     \
 273 ({                                                                                      \
 274         void *__cu_to = (to);                                                           \
 275         const void __user *__cu_from = (from);                                          \
 276         long __cu_len = (n);                                                            \
 277                                                                                         \
 278         __chk_user_ptr(__cu_from);                                                      \
 279         if (__access_ok(__cu_from, __cu_len, get_fs()))                                 \
 280                 __cu_len = __copy_user((void __user *) __cu_to, __cu_from, __cu_len);   \
 281         __cu_len;                                                                       \
 282 })
 283
 284 #define __copy_in_user(to, from, size)  __copy_user((to), (from), (size))
 285
 286 static inline unsigned long
 287 copy_in_user (void __user *to, const void __user *from, unsigned long n)
 288 {
 289         if (likely(access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n)))
 290                 n = __copy_user(to, from, n);
 291         return n;
 292 }
 293
 294 extern unsigned long __do_clear_user (void __user *, unsigned long);
 295
 296 #define __clear_user(to, n)             __do_clear_user(to, n)
 297
 298 #define clear_user(to, n)                                       \
 299 ({                                                              \
 300         unsigned long __cu_len = (n);                           \
 301         if (__access_ok(to, __cu_len, get_fs()))                \
 302                 __cu_len = __do_clear_user(to, __cu_len);       \
 303         __cu_len;                                               \
 304 })
 305
 306
 307 /*
 308  * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
 309  * strlen.
 310  */
 311 extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);
 312
 313 #define strncpy_from_user(to, from, n)                                  \
 314 ({                                                                      \
 315         const char __user * __sfu_from = (from);                        \
 316         long __sfu_ret = -EFAULT;                                       \
 317         if (__access_ok(__sfu_from, 0, get_fs()))                       \
 318                 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
 319         __sfu_ret;                                                      \
 320 })
 321
 322 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 323 extern unsigned long __strlen_user (const char __user *);
 324
 325 #define strlen_user(str)                                \
 326 ({                                                      \
 327         const char __user *__su_str = (str);            \
 328         unsigned long __su_ret = 0;                     \
 329         if (__access_ok(__su_str, 0, get_fs()))         \
 330                 __su_ret = __strlen_user(__su_str);     \
 331         __su_ret;                                       \
 332 })
 333
 334 /*
 335  * Returns: 0 if exception before NUL or reaching the supplied limit
 336  * (N), a value greater than N if the limit would be exceeded, else
 337  * strlen.
 338  */
 339 extern unsigned long __strnlen_user (const char __user *, long);
 340
 341 #define strnlen_user(str, len)                                  \
 342 ({                                                              \
 343         const char __user *__su_str = (str);                    \
 344         unsigned long __su_ret = 0;                             \
 345         if (__access_ok(__su_str, 0, get_fs()))                 \
 346                 __su_ret = __strnlen_user(__su_str, len);       \
 347         __su_ret;                                               \
 348 })
 349
 350 /* Generic code can't deal with the location-relative format that we use for compactness.  */
 351 #define ARCH_HAS_SORT_EXTABLE
 352 #define ARCH_HAS_SEARCH_EXTABLE
 353
 354 struct exception_table_entry {
 355         int addr;       /* location-relative address of insn this fixup is for */
 356         int cont;       /* location-relative continuation addr.; if bit 2 is set, r9 is set to 0 */
 357 };
 358
 359 extern void ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e);
 360 extern const struct exception_table_entry *search_exception_tables (unsigned long addr);
 361
 362 static inline int
 363 ia64_done_with_exception (struct pt_regs *regs)
 364 {
 365         const struct exception_table_entry *e;
 366         e = search_exception_tables(regs->cr_iip + ia64_psr(regs)->ri);
 367         if (e) {
 368                 ia64_handle_exception(regs, e);
 369                 return 1;
 370         }
 371         return 0;
 372 }
 373
 374 #define ARCH_HAS_TRANSLATE_MEM_PTR      1
 375 static __inline__ char *
 376 xlate_dev_mem_ptr (unsigned long p)
 377 {
 378         struct page *page;
 379         char * ptr;
 380
 381         page = pfn_to_page(p >> PAGE_SHIFT);
 382         if (PageUncached(page))
 383                 ptr = (char *)p + __IA64_UNCACHED_OFFSET;
 384         else
 385                 ptr = __va(p);
 386
 387         return ptr;
 388 }
 389
 390 /*
 391  * Convert a virtual cached kernel memory pointer to an uncached pointer
 392  */
 393 static __inline__ char *
 394 xlate_dev_kmem_ptr (char * p)
 395 {
 396         struct page *page;
 397         char * ptr;
 398
 399         page = virt_to_page((unsigned long)p >> PAGE_SHIFT);
 400         if (PageUncached(page))
 401                 ptr = (char *)__pa(p) + __IA64_UNCACHED_OFFSET;
 402         else
 403                 ptr = p;
 404
 405         return ptr;
 406 }
 407
 408 #endif /* _ASM_IA64_UACCESS_H */