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/page-flags.h>
  37 #include <linux/mm.h>
  38
  39 #include <asm/intrinsics.h>
  40 #include <asm/pgtable.h>
  41 #include <asm/io.h>
  42
  43 /*
  44  * For historical reasons, the following macros are grossly misnamed:
  45  */
  46 #define KERNEL_DS       ((mm_segment_t) { ~0UL })               /* cf. access_ok() */
  47 #define USER_DS         ((mm_segment_t) { TASK_SIZE-1 })        /* cf. access_ok() */
  48
  49 #define get_ds()  (KERNEL_DS)
  50 #define get_fs()  (current_thread_info()->addr_limit)
  51 #define set_fs(x) (current_thread_info()->addr_limit = (x))
  52
  53 #define segment_eq(a, b)        ((a).seg == (b).seg)
  54
  55 /*
  56  * When accessing user memory, we need to make sure the entire area really is in
  57  * user-level space.  In order to do this efficiently, we make sure that the page at
  58  * address TASK_SIZE is never valid.  We also need to make sure that the address doesn't
  59  * point inside the virtually mapped linear page table.
  60  */
  61 #define __access_ok(addr, size, segment)                                                \
  62 ({                                                                                      \
  63         __chk_user_ptr(addr);                                                           \
  64         (likely((unsigned long) (addr) <= (segment).seg)                                \
  65          && ((segment).seg == KERNEL_DS.seg                                             \
  66              || likely(REGION_OFFSET((unsigned long) (addr)) < RGN_MAP_LIMIT)));        \
  67 })
  68 #define access_ok(type, addr, size)     __access_ok((addr), (size), get_fs())
  69
  70 /*
  71  * These are the main single-value transfer routines.  They automatically
  72  * use the right size if we just have the right pointer type.
  73  *
  74  * Careful to not
  75  * (a) re-use the arguments for side effects (sizeof/typeof is ok)
  76  * (b) require any knowledge of processes at this stage
  77  */
  78 #define put_user(x, ptr)        __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)), get_fs())
  79 #define get_user(x, ptr)        __get_user_check((x), (ptr), sizeof(*(ptr)), get_fs())
  80
  81 /*
  82  * The "__xxx" versions do not do address space checking, useful when
  83  * doing multiple accesses to the same area (the programmer has to do the
  84  * checks by hand with "access_ok()")
  85  */
  86 #define __put_user(x, ptr)      __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
  87 #define __get_user(x, ptr)      __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  88
  89 extern long __put_user_unaligned_unknown (void);
  90
  91 #define __put_user_unaligned(x, ptr)                                                            \
  92 ({                                                                                              \
  93         long __ret;                                                                             \
  94         switch (sizeof(*(ptr))) {                                                               \
  95                 case 1: __ret = __put_user((x), (ptr)); break;                                  \
  96                 case 2: __ret = (__put_user((x), (u8 __user *)(ptr)))                           \
  97                         | (__put_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;              \
  98                 case 4: __ret = (__put_user((x), (u16 __user *)(ptr)))                          \
  99                         | (__put_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;            \
 100                 case 8: __ret = (__put_user((x), (u32 __user *)(ptr)))                          \
 101                         | (__put_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;            \
 102                 default: __ret = __put_user_unaligned_unknown();                                \
 103         }                                                                                       \
 104         __ret;                                                                                  \
 105 })
 106
 107 extern long __get_user_unaligned_unknown (void);
 108
 109 #define __get_user_unaligned(x, ptr)                                                            \
 110 ({                                                                                              \
 111         long __ret;                                                                             \
 112         switch (sizeof(*(ptr))) {                                                               \
 113                 case 1: __ret = __get_user((x), (ptr)); break;                                  \
 114                 case 2: __ret = (__get_user((x), (u8 __user *)(ptr)))                           \
 115                         | (__get_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;              \
 116                 case 4: __ret = (__get_user((x), (u16 __user *)(ptr)))                          \
 117                         | (__get_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;            \
 118                 case 8: __ret = (__get_user((x), (u32 __user *)(ptr)))                          \
 119                         | (__get_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;            \
 120                 default: __ret = __get_user_unaligned_unknown();                                \
 121         }                                                                                       \
 122         __ret;                                                                                  \
 123 })
 124
 125 #ifdef ASM_SUPPORTED
 126   struct __large_struct { unsigned long buf[100]; };
 127 # define __m(x) (*(struct __large_struct __user *)(x))
 128
 129 /* We need to declare the __ex_table section before we can use it in .xdata.  */
 130 asm (".section \"__ex_table\", \"a\"\n\t.previous");
 131
 132 # define __get_user_size(val, addr, n, err)                                                     \
 133 do {                                                                                            \
 134         register long __gu_r8 asm ("r8") = 0;                                                   \
 135         register long __gu_r9 asm ("r9");                                                       \
 136         asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n"     \
 137              "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n"                                         \
 138              "[1:]"                                                                             \
 139              : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8));                    \
 140         (err) = __gu_r8;                                                                        \
 141         (val) = __gu_r9;                                                                        \
 142 } while (0)
 143
 144 /*
 145  * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it.  This
 146  * is because they do not write to any memory gcc knows about, so there are no aliasing
 147  * issues.
 148  */
 149 # define __put_user_size(val, addr, n, err)                                                     \
 150 do {                                                                                            \
 151         register long __pu_r8 asm ("r8") = 0;                                                   \
 152         asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \
 153                       "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n"                                  \
 154                       "[1:]"                                                                    \
 155                       : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8));               \
 156         (err) = __pu_r8;                                                                        \
 157 } while (0)
 158
 159 #else /* !ASM_SUPPORTED */
 160 # define RELOC_TYPE     2       /* ip-rel */
 161 # define __get_user_size(val, addr, n, err)                             \
 162 do {                                                                    \
 163         __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE);   \
 164         (err) = ia64_getreg(_IA64_REG_R8);                              \
 165         (val) = ia64_getreg(_IA64_REG_R9);                              \
 166 } while (0)
 167 # define __put_user_size(val, addr, n, err)                             \
 168 do {                                                                    \
 169         __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE,    \
 170                   (__force unsigned long) (val));                       \
 171         (err) = ia64_getreg(_IA64_REG_R8);                              \
 172 } while (0)
 173 #endif /* !ASM_SUPPORTED */
 174
 175 extern void __get_user_unknown (void);
 176
 177 /*
 178  * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
 179  * could clobber r8 and r9 (among others).  Thus, be careful not to evaluate it while
 180  * using r8/r9.
 181  */
 182 #define __do_get_user(check, x, ptr, size, segment)                                     \
 183 ({                                                                                      \
 184         const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);                              \
 185         __typeof__ (size) __gu_size = (size);                                           \
 186         long __gu_err = -EFAULT;                                                        \
 187         unsigned long __gu_val = 0;                                                     \
 188         if (!check || __access_ok(__gu_ptr, size, segment))                             \
 189                 switch (__gu_size) {                                                    \
 190                       case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break;  \
 191                       case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break;  \
 192                       case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break;  \
 193                       case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break;  \
 194                       default: __get_user_unknown(); break;                             \
 195                 }                                                                       \
 196         (x) = (__force __typeof__(*(__gu_ptr))) __gu_val;                               \
 197         __gu_err;                                                                       \
 198 })
 199
 200 #define __get_user_nocheck(x, ptr, size)        __do_get_user(0, x, ptr, size, KERNEL_DS)
 201 #define __get_user_check(x, ptr, size, segment) __do_get_user(1, x, ptr, size, segment)
 202
 203 extern void __put_user_unknown (void);
 204
 205 /*
 206  * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
 207  * could clobber r8 (among others).  Thus, be careful not to evaluate them while using r8.
 208  */
 209 #define __do_put_user(check, x, ptr, size, segment)                                     \
 210 ({                                                                                      \
 211         __typeof__ (x) __pu_x = (x);                                                    \
 212         __typeof__ (*(ptr)) __user *__pu_ptr = (ptr);                                   \
 213         __typeof__ (size) __pu_size = (size);                                           \
 214         long __pu_err = -EFAULT;                                                        \
 215                                                                                         \
 216         if (!check || __access_ok(__pu_ptr, __pu_size, segment))                        \
 217                 switch (__pu_size) {                                                    \
 218                       case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break;    \
 219                       case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break;    \
 220                       case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break;    \
 221                       case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break;    \
 222                       default: __put_user_unknown(); break;                             \
 223                 }                                                                       \
 224         __pu_err;                                                                       \
 225 })
 226
 227 #define __put_user_nocheck(x, ptr, size)        __do_put_user(0, x, ptr, size, KERNEL_DS)
 228 #define __put_user_check(x, ptr, size, segment) __do_put_user(1, x, ptr, size, segment)
 229
 230 /*
 231  * Complex access routines
 232  */
 233 extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
 234                                                unsigned long count);
 235
 236 static inline unsigned long
 237 __copy_to_user (void __user *to, const void *from, unsigned long count)
 238 {
 239         check_object_size(from, count, true);
 240
 241         return __copy_user(to, (__force void __user *) from, count);
 242 }
 243
 244 static inline unsigned long
 245 __copy_from_user (void *to, const void __user *from, unsigned long count)
 246 {
 247         check_object_size(to, count, false);
 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                 check_object_size(__cu_from, __cu_len, true);                   \
 262                 __cu_len = __copy_user(__cu_to, (__force void __user *)  __cu_from, __cu_len);  \
 263         }                                                                               \
 264         __cu_len;                                                                       \
 265 })
 266
 267 static inline unsigned long
 268 copy_from_user(void *to, const void __user *from, unsigned long n)
 269 {
 270         check_object_size(to, n, false);
 271         if (likely(__access_ok(from, n, get_fs())))
 272                 n = __copy_user((__force void __user *) to, from, n);
 273         else
 274                 memset(to, 0, n);
 275         return n;
 276 }
 277
 278 #define __copy_in_user(to, from, size)  __copy_user((to), (from), (size))
 279
 280 static inline unsigned long
 281 copy_in_user (void __user *to, const void __user *from, unsigned long n)
 282 {
 283         if (likely(access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n)))
 284                 n = __copy_user(to, from, n);
 285         return n;
 286 }
 287
 288 extern unsigned long __do_clear_user (void __user *, unsigned long);
 289
 290 #define __clear_user(to, n)             __do_clear_user(to, n)
 291
 292 #define clear_user(to, n)                                       \
 293 ({                                                              \
 294         unsigned long __cu_len = (n);                           \
 295         if (__access_ok(to, __cu_len, get_fs()))                \
 296                 __cu_len = __do_clear_user(to, __cu_len);       \
 297         __cu_len;                                               \
 298 })
 299
 300
 301 /*
 302  * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
 303  * strlen.
 304  */
 305 extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);
 306
 307 #define strncpy_from_user(to, from, n)                                  \
 308 ({                                                                      \
 309         const char __user * __sfu_from = (from);                        \
 310         long __sfu_ret = -EFAULT;                                       \
 311         if (__access_ok(__sfu_from, 0, get_fs()))                       \
 312                 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
 313         __sfu_ret;                                                      \
 314 })
 315
 316 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 317 extern unsigned long __strlen_user (const char __user *);
 318
 319 #define strlen_user(str)                                \
 320 ({                                                      \
 321         const char __user *__su_str = (str);            \
 322         unsigned long __su_ret = 0;                     \
 323         if (__access_ok(__su_str, 0, get_fs()))         \
 324                 __su_ret = __strlen_user(__su_str);     \
 325         __su_ret;                                       \
 326 })
 327
 328 /*
 329  * Returns: 0 if exception before NUL or reaching the supplied limit
 330  * (N), a value greater than N if the limit would be exceeded, else
 331  * strlen.
 332  */
 333 extern unsigned long __strnlen_user (const char __user *, long);
 334
 335 #define strnlen_user(str, len)                                  \
 336 ({                                                              \
 337         const char __user *__su_str = (str);                    \
 338         unsigned long __su_ret = 0;                             \
 339         if (__access_ok(__su_str, 0, get_fs()))                 \
 340                 __su_ret = __strnlen_user(__su_str, len);       \
 341         __su_ret;                                               \
 342 })
 343
 344 #define ARCH_HAS_RELATIVE_EXTABLE
 345
 346 struct exception_table_entry {
 347         int insn;       /* location-relative address of insn this fixup is for */
 348         int fixup;      /* location-relative continuation addr.; if bit 2 is set, r9 is set to 0 */
 349 };
 350
 351 #define ARCH_HAS_TRANSLATE_MEM_PTR      1
 352 static __inline__ void *
 353 xlate_dev_mem_ptr(phys_addr_t p)
 354 {
 355         struct page *page;
 356         void *ptr;
 357
 358         page = pfn_to_page(p >> PAGE_SHIFT);
 359         if (PageUncached(page))
 360                 ptr = (void *)p + __IA64_UNCACHED_OFFSET;
 361         else
 362                 ptr = __va(p);
 363
 364         return ptr;
 365 }
 366
 367 /*
 368  * Convert a virtual cached kernel memory pointer to an uncached pointer
 369  */
 370 static __inline__ void *
 371 xlate_dev_kmem_ptr(void *p)
 372 {
 373         struct page *page;
 374         void *ptr;
 375
 376         page = virt_to_page((unsigned long)p);
 377         if (PageUncached(page))
 378                 ptr = (void *)__pa(p) + __IA64_UNCACHED_OFFSET;
 379         else
 380                 ptr = p;
 381
 382         return ptr;
 383 }
 384
 385 #endif /* _ASM_IA64_UACCESS_H */