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,    \
 175                   (__force unsigned long) (val));                       \
 176         (err) = ia64_getreg(_IA64_REG_R8);                              \
 177 } while (0)
 178 #endif /* !ASM_SUPPORTED */
 179
 180 extern void __get_user_unknown (void);
 181
 182 /*
 183  * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
 184  * could clobber r8 and r9 (among others).  Thus, be careful not to evaluate it while
 185  * using r8/r9.
 186  */
 187 #define __do_get_user(check, x, ptr, size, segment)                                     \
 188 ({                                                                                      \
 189         const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);                              \
 190         __typeof__ (size) __gu_size = (size);                                           \
 191         long __gu_err = -EFAULT;                                                        \
 192         unsigned long __gu_val = 0;                                                     \
 193         if (!check || __access_ok(__gu_ptr, size, segment))                             \
 194                 switch (__gu_size) {                                                    \
 195                       case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break;  \
 196                       case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break;  \
 197                       case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break;  \
 198                       case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break;  \
 199                       default: __get_user_unknown(); break;                             \
 200                 }                                                                       \
 201         (x) = (__force __typeof__(*(__gu_ptr))) __gu_val;                               \
 202         __gu_err;                                                                       \
 203 })
 204
 205 #define __get_user_nocheck(x, ptr, size)        __do_get_user(0, x, ptr, size, KERNEL_DS)
 206 #define __get_user_check(x, ptr, size, segment) __do_get_user(1, x, ptr, size, segment)
 207
 208 extern void __put_user_unknown (void);
 209
 210 /*
 211  * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
 212  * could clobber r8 (among others).  Thus, be careful not to evaluate them while using r8.
 213  */
 214 #define __do_put_user(check, x, ptr, size, segment)                                     \
 215 ({                                                                                      \
 216         __typeof__ (x) __pu_x = (x);                                                    \
 217         __typeof__ (*(ptr)) __user *__pu_ptr = (ptr);                                   \
 218         __typeof__ (size) __pu_size = (size);                                           \
 219         long __pu_err = -EFAULT;                                                        \
 220                                                                                         \
 221         if (!check || __access_ok(__pu_ptr, __pu_size, segment))                        \
 222                 switch (__pu_size) {                                                    \
 223                       case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break;    \
 224                       case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break;    \
 225                       case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break;    \
 226                       case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break;    \
 227                       default: __put_user_unknown(); break;                             \
 228                 }                                                                       \
 229         __pu_err;                                                                       \
 230 })
 231
 232 #define __put_user_nocheck(x, ptr, size)        __do_put_user(0, x, ptr, size, KERNEL_DS)
 233 #define __put_user_check(x, ptr, size, segment) __do_put_user(1, x, ptr, size, segment)
 234
 235 /*
 236  * Complex access routines
 237  */
 238 extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
 239                                                unsigned long count);
 240
 241 static inline unsigned long
 242 __copy_to_user (void __user *to, const void *from, unsigned long count)
 243 {
 244         if (!__builtin_constant_p(count))
 245                 check_object_size(from, count, true);
 246
 247         return __copy_user(to, (__force void __user *) from, count);
 248 }
 249
 250 static inline unsigned long
 251 __copy_from_user (void *to, const void __user *from, unsigned long count)
 252 {
 253         if (!__builtin_constant_p(count))
 254                 check_object_size(to, count, false);
 255
 256         return __copy_user((__force 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                 if (!__builtin_constant_p(n))                                           \
 269                         check_object_size(__cu_from, __cu_len, true);                   \
 270                 __cu_len = __copy_user(__cu_to, (__force void __user *)  __cu_from, __cu_len);  \
 271         }                                                                               \
 272         __cu_len;                                                                       \
 273 })
 274
 275 #define copy_from_user(to, from, n)                                                     \
 276 ({                                                                                      \
 277         void *__cu_to = (to);                                                           \
 278         const void __user *__cu_from = (from);                                          \
 279         long __cu_len = (n);                                                            \
 280                                                                                         \
 281         __chk_user_ptr(__cu_from);                                                      \
 282         if (__access_ok(__cu_from, __cu_len, get_fs())) {                               \
 283                 if (!__builtin_constant_p(n))                                           \
 284                         check_object_size(__cu_to, __cu_len, false);                    \
 285                 __cu_len = __copy_user((__force void __user *) __cu_to, __cu_from, __cu_len);   \
 286         }                                                                               \
 287         __cu_len;                                                                       \
 288 })
 289
 290 #define __copy_in_user(to, from, size)  __copy_user((to), (from), (size))
 291
 292 static inline unsigned long
 293 copy_in_user (void __user *to, const void __user *from, unsigned long n)
 294 {
 295         if (likely(access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n)))
 296                 n = __copy_user(to, from, n);
 297         return n;
 298 }
 299
 300 extern unsigned long __do_clear_user (void __user *, unsigned long);
 301
 302 #define __clear_user(to, n)             __do_clear_user(to, n)
 303
 304 #define clear_user(to, n)                                       \
 305 ({                                                              \
 306         unsigned long __cu_len = (n);                           \
 307         if (__access_ok(to, __cu_len, get_fs()))                \
 308                 __cu_len = __do_clear_user(to, __cu_len);       \
 309         __cu_len;                                               \
 310 })
 311
 312
 313 /*
 314  * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
 315  * strlen.
 316  */
 317 extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);
 318
 319 #define strncpy_from_user(to, from, n)                                  \
 320 ({                                                                      \
 321         const char __user * __sfu_from = (from);                        \
 322         long __sfu_ret = -EFAULT;                                       \
 323         if (__access_ok(__sfu_from, 0, get_fs()))                       \
 324                 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
 325         __sfu_ret;                                                      \
 326 })
 327
 328 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 329 extern unsigned long __strlen_user (const char __user *);
 330
 331 #define strlen_user(str)                                \
 332 ({                                                      \
 333         const char __user *__su_str = (str);            \
 334         unsigned long __su_ret = 0;                     \
 335         if (__access_ok(__su_str, 0, get_fs()))         \
 336                 __su_ret = __strlen_user(__su_str);     \
 337         __su_ret;                                       \
 338 })
 339
 340 /*
 341  * Returns: 0 if exception before NUL or reaching the supplied limit
 342  * (N), a value greater than N if the limit would be exceeded, else
 343  * strlen.
 344  */
 345 extern unsigned long __strnlen_user (const char __user *, long);
 346
 347 #define strnlen_user(str, len)                                  \
 348 ({                                                              \
 349         const char __user *__su_str = (str);                    \
 350         unsigned long __su_ret = 0;                             \
 351         if (__access_ok(__su_str, 0, get_fs()))                 \
 352                 __su_ret = __strnlen_user(__su_str, len);       \
 353         __su_ret;                                               \
 354 })
 355
 356 #define ARCH_HAS_RELATIVE_EXTABLE
 357
 358 struct exception_table_entry {
 359         int insn;       /* location-relative address of insn this fixup is for */
 360         int fixup;      /* location-relative continuation addr.; if bit 2 is set, r9 is set to 0 */
 361 };
 362
 363 extern void ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e);
 364 extern const struct exception_table_entry *search_exception_tables (unsigned long addr);
 365
 366 static inline int
 367 ia64_done_with_exception (struct pt_regs *regs)
 368 {
 369         const struct exception_table_entry *e;
 370         e = search_exception_tables(regs->cr_iip + ia64_psr(regs)->ri);
 371         if (e) {
 372                 ia64_handle_exception(regs, e);
 373                 return 1;
 374         }
 375         return 0;
 376 }
 377
 378 #define ARCH_HAS_TRANSLATE_MEM_PTR      1
 379 static __inline__ void *
 380 xlate_dev_mem_ptr(phys_addr_t p)
 381 {
 382         struct page *page;
 383         void *ptr;
 384
 385         page = pfn_to_page(p >> PAGE_SHIFT);
 386         if (PageUncached(page))
 387                 ptr = (void *)p + __IA64_UNCACHED_OFFSET;
 388         else
 389                 ptr = __va(p);
 390
 391         return ptr;
 392 }
 393
 394 /*
 395  * Convert a virtual cached kernel memory pointer to an uncached pointer
 396  */
 397 static __inline__ void *
 398 xlate_dev_kmem_ptr(void *p)
 399 {
 400         struct page *page;
 401         void *ptr;
 402
 403         page = virt_to_page((unsigned long)p);
 404         if (PageUncached(page))
 405                 ptr = (void *)__pa(p) + __IA64_UNCACHED_OFFSET;
 406         else
 407                 ptr = p;
 408
 409         return ptr;
 410 }
 411
 412 #endif /* _ASM_IA64_UACCESS_H */