kernel/arch/sparc/include/asm/uaccess_32.h

   1 /*
   2  * uaccess.h: User space memore access functions.
   3  *
   4  * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
   5  * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
   6  */
   7 #ifndef _ASM_UACCESS_H
   8 #define _ASM_UACCESS_H
   9
  10 #ifdef __KERNEL__
  11 #include <linux/compiler.h>
  12 #include <linux/sched.h>
  13 #include <linux/string.h>
  14 #include <linux/errno.h>
  15 #endif
  16
  17 #ifndef __ASSEMBLY__
  18
  19 #include <asm/processor.h>
  20
  21 #define ARCH_HAS_SORT_EXTABLE
  22 #define ARCH_HAS_SEARCH_EXTABLE
  23
  24 /* Sparc is not segmented, however we need to be able to fool access_ok()
  25  * when doing system calls from kernel mode legitimately.
  26  *
  27  * "For historical reasons, these macros are grossly misnamed." -Linus
  28  */
  29
  30 #define KERNEL_DS   ((mm_segment_t) { 0 })
  31 #define USER_DS     ((mm_segment_t) { -1 })
  32
  33 #define VERIFY_READ     0
  34 #define VERIFY_WRITE    1
  35
  36 #define get_ds()        (KERNEL_DS)
  37 #define get_fs()        (current->thread.current_ds)
  38 #define set_fs(val)     ((current->thread.current_ds) = (val))
  39
  40 #define segment_eq(a, b) ((a).seg == (b).seg)
  41
  42 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
  43  * can be fairly lightweight.
  44  * No one can read/write anything from userland in the kernel space by setting
  45  * large size and address near to PAGE_OFFSET - a fault will break his intentions.
  46  */
  47 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
  48 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
  49 #define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size)))
  50 #define access_ok(type, addr, size) \
  51         ({ (void)(type); __access_ok((unsigned long)(addr), size); })
  52
  53 /*
  54  * The exception table consists of pairs of addresses: the first is the
  55  * address of an instruction that is allowed to fault, and the second is
  56  * the address at which the program should continue.  No registers are
  57  * modified, so it is entirely up to the continuation code to figure out
  58  * what to do.
  59  *
  60  * All the routines below use bits of fixup code that are out of line
  61  * with the main instruction path.  This means when everything is well,
  62  * we don't even have to jump over them.  Further, they do not intrude
  63  * on our cache or tlb entries.
  64  *
  65  * There is a special way how to put a range of potentially faulting
  66  * insns (like twenty ldd/std's with now intervening other instructions)
  67  * You specify address of first in insn and 0 in fixup and in the next
  68  * exception_table_entry you specify last potentially faulting insn + 1
  69  * and in fixup the routine which should handle the fault.
  70  * That fixup code will get
  71  * (faulting_insn_address - first_insn_in_the_range_address)/4
  72  * in %g2 (ie. index of the faulting instruction in the range).
  73  */
  74
  75 struct exception_table_entry
  76 {
  77         unsigned long insn, fixup;
  78 };
  79
  80 /* Returns 0 if exception not found and fixup otherwise.  */
  81 unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
  82
  83 void __ret_efault(void);
  84
  85 /* Uh, these should become the main single-value transfer routines..
  86  * They automatically use the right size if we just have the right
  87  * pointer type..
  88  *
  89  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  90  * and yet we don't want to do any pointers, because that is too much
  91  * of a performance impact. Thus we have a few rather ugly macros here,
  92  * and hide all the ugliness from the user.
  93  */
  94 #define put_user(x, ptr) ({ \
  95         unsigned long __pu_addr = (unsigned long)(ptr); \
  96         __chk_user_ptr(ptr); \
  97         __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \
  98 })
  99
 100 #define get_user(x, ptr) ({ \
 101         unsigned long __gu_addr = (unsigned long)(ptr); \
 102         __chk_user_ptr(ptr); \
 103         __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \
 104 })
 105
 106 /*
 107  * The "__xxx" versions do not do address space checking, useful when
 108  * doing multiple accesses to the same area (the user has to do the
 109  * checks by hand with "access_ok()")
 110  */
 111 #define __put_user(x, ptr) \
 112         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 113 #define __get_user(x, ptr) \
 114     __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr)))
 115
 116 struct __large_struct { unsigned long buf[100]; };
 117 #define __m(x) ((struct __large_struct __user *)(x))
 118
 119 #define __put_user_check(x, addr, size) ({ \
 120         register int __pu_ret; \
 121         if (__access_ok(addr, size)) { \
 122                 switch (size) { \
 123                 case 1: \
 124                         __put_user_asm(x, b, addr, __pu_ret); \
 125                         break; \
 126                 case 2: \
 127                         __put_user_asm(x, h, addr, __pu_ret); \
 128                         break; \
 129                 case 4: \
 130                         __put_user_asm(x, , addr, __pu_ret); \
 131                         break; \
 132                 case 8: \
 133                         __put_user_asm(x, d, addr, __pu_ret); \
 134                         break; \
 135                 default: \
 136                         __pu_ret = __put_user_bad(); \
 137                         break; \
 138                 } \
 139         } else { \
 140                 __pu_ret = -EFAULT; \
 141         } \
 142         __pu_ret; \
 143 })
 144
 145 #define __put_user_nocheck(x, addr, size) ({                    \
 146         register int __pu_ret;                                  \
 147         switch (size) {                                         \
 148         case 1: __put_user_asm(x, b, addr, __pu_ret); break;    \
 149         case 2: __put_user_asm(x, h, addr, __pu_ret); break;    \
 150         case 4: __put_user_asm(x, , addr, __pu_ret); break;     \
 151         case 8: __put_user_asm(x, d, addr, __pu_ret); break;    \
 152         default: __pu_ret = __put_user_bad(); break;            \
 153         } \
 154         __pu_ret; \
 155 })
 156
 157 #define __put_user_asm(x, size, addr, ret)                              \
 158 __asm__ __volatile__(                                                   \
 159                 "/* Put user asm, inline. */\n"                         \
 160         "1:\t"  "st"#size " %1, %2\n\t"                                 \
 161                 "clr    %0\n"                                           \
 162         "2:\n\n\t"                                                      \
 163                 ".section .fixup,#alloc,#execinstr\n\t"                 \
 164                 ".align 4\n"                                            \
 165         "3:\n\t"                                                        \
 166                 "b      2b\n\t"                                         \
 167                 " mov   %3, %0\n\t"                                     \
 168                 ".previous\n\n\t"                                       \
 169                 ".section __ex_table,#alloc\n\t"                        \
 170                 ".align 4\n\t"                                          \
 171                 ".word  1b, 3b\n\t"                                     \
 172                 ".previous\n\n\t"                                       \
 173                : "=&r" (ret) : "r" (x), "m" (*__m(addr)),               \
 174                  "i" (-EFAULT))
 175
 176 int __put_user_bad(void);
 177
 178 #define __get_user_check(x, addr, size, type) ({ \
 179         register int __gu_ret; \
 180         register unsigned long __gu_val; \
 181         if (__access_ok(addr, size)) { \
 182                 switch (size) { \
 183                 case 1: \
 184                          __get_user_asm(__gu_val, ub, addr, __gu_ret); \
 185                         break; \
 186                 case 2: \
 187                         __get_user_asm(__gu_val, uh, addr, __gu_ret); \
 188                         break; \
 189                 case 4: \
 190                         __get_user_asm(__gu_val, , addr, __gu_ret); \
 191                         break; \
 192                 case 8: \
 193                         __get_user_asm(__gu_val, d, addr, __gu_ret); \
 194                         break; \
 195                 default: \
 196                         __gu_val = 0; \
 197                         __gu_ret = __get_user_bad(); \
 198                         break; \
 199                 } \
 200          } else { \
 201                  __gu_val = 0; \
 202                  __gu_ret = -EFAULT; \
 203         } \
 204         x = (__force type) __gu_val; \
 205         __gu_ret; \
 206 })
 207
 208 #define __get_user_check_ret(x, addr, size, type, retval) ({ \
 209         register unsigned long __gu_val __asm__ ("l1"); \
 210         if (__access_ok(addr, size)) { \
 211                 switch (size) { \
 212                 case 1: \
 213                         __get_user_asm_ret(__gu_val, ub, addr, retval); \
 214                         break; \
 215                 case 2: \
 216                         __get_user_asm_ret(__gu_val, uh, addr, retval); \
 217                         break; \
 218                 case 4: \
 219                         __get_user_asm_ret(__gu_val, , addr, retval); \
 220                         break; \
 221                 case 8: \
 222                         __get_user_asm_ret(__gu_val, d, addr, retval); \
 223                         break; \
 224                 default: \
 225                         if (__get_user_bad()) \
 226                                 return retval; \
 227                 } \
 228                 x = (__force type) __gu_val; \
 229         } else \
 230                 return retval; \
 231 })
 232
 233 #define __get_user_nocheck(x, addr, size, type) ({                      \
 234         register int __gu_ret;                                          \
 235         register unsigned long __gu_val;                                \
 236         switch (size) {                                                 \
 237         case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break;    \
 238         case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break;    \
 239         case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break;      \
 240         case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break;     \
 241         default:                                                        \
 242                 __gu_val = 0;                                           \
 243                 __gu_ret = __get_user_bad();                            \
 244                 break;                                                  \
 245         }                                                               \
 246         x = (__force type) __gu_val;                                    \
 247         __gu_ret;                                                       \
 248 })
 249
 250 #define __get_user_nocheck_ret(x, addr, size, type, retval) ({          \
 251         register unsigned long __gu_val __asm__ ("l1");                 \
 252         switch (size) {                                                 \
 253         case 1: __get_user_asm_ret(__gu_val, ub, addr, retval); break;  \
 254         case 2: __get_user_asm_ret(__gu_val, uh, addr, retval); break;  \
 255         case 4: __get_user_asm_ret(__gu_val, , addr, retval);  break;   \
 256         case 8: __get_user_asm_ret(__gu_val, d, addr, retval); break;   \
 257         default:                                                        \
 258                 if (__get_user_bad())                                   \
 259                         return retval;                                  \
 260         }                                                               \
 261         x = (__force type) __gu_val;                                    \
 262 })
 263
 264 #define __get_user_asm(x, size, addr, ret)                              \
 265 __asm__ __volatile__(                                                   \
 266                 "/* Get user asm, inline. */\n"                         \
 267         "1:\t"  "ld"#size " %2, %1\n\t"                                 \
 268                 "clr    %0\n"                                           \
 269         "2:\n\n\t"                                                      \
 270                 ".section .fixup,#alloc,#execinstr\n\t"                 \
 271                 ".align 4\n"                                            \
 272         "3:\n\t"                                                        \
 273                 "clr    %1\n\t"                                         \
 274                 "b      2b\n\t"                                         \
 275                 " mov   %3, %0\n\n\t"                                   \
 276                 ".previous\n\t"                                         \
 277                 ".section __ex_table,#alloc\n\t"                        \
 278                 ".align 4\n\t"                                          \
 279                 ".word  1b, 3b\n\n\t"                                   \
 280                 ".previous\n\t"                                         \
 281                : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)),             \
 282                  "i" (-EFAULT))
 283
 284 #define __get_user_asm_ret(x, size, addr, retval)                       \
 285 if (__builtin_constant_p(retval) && retval == -EFAULT)                  \
 286         __asm__ __volatile__(                                           \
 287                         "/* Get user asm ret, inline. */\n"             \
 288                 "1:\t"  "ld"#size " %1, %0\n\n\t"                       \
 289                         ".section __ex_table,#alloc\n\t"                \
 290                         ".align 4\n\t"                                  \
 291                         ".word  1b,__ret_efault\n\n\t"                  \
 292                         ".previous\n\t"                                 \
 293                        : "=&r" (x) : "m" (*__m(addr)));                 \
 294 else                                                                    \
 295         __asm__ __volatile__(                                           \
 296                         "/* Get user asm ret, inline. */\n"             \
 297                 "1:\t"  "ld"#size " %1, %0\n\n\t"                       \
 298                         ".section .fixup,#alloc,#execinstr\n\t"         \
 299                         ".align 4\n"                                    \
 300                 "3:\n\t"                                                \
 301                         "ret\n\t"                                       \
 302                         " restore %%g0, %2, %%o0\n\n\t"                 \
 303                         ".previous\n\t"                                 \
 304                         ".section __ex_table,#alloc\n\t"                \
 305                         ".align 4\n\t"                                  \
 306                         ".word  1b, 3b\n\n\t"                           \
 307                         ".previous\n\t"                                 \
 308                        : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
 309
 310 int __get_user_bad(void);
 311
 312 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
 313
 314 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
 315 {
 316         if (n && __access_ok((unsigned long) to, n))
 317                 return __copy_user(to, (__force void __user *) from, n);
 318         else
 319                 return n;
 320 }
 321
 322 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
 323 {
 324         return __copy_user(to, (__force void __user *) from, n);
 325 }
 326
 327 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 328 {
 329         if (n && __access_ok((unsigned long) from, n))
 330                 return __copy_user((__force void __user *) to, from, n);
 331         else
 332                 return n;
 333 }
 334
 335 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
 336 {
 337         return __copy_user((__force void __user *) to, from, n);
 338 }
 339
 340 #define __copy_to_user_inatomic __copy_to_user
 341 #define __copy_from_user_inatomic __copy_from_user
 342
 343 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
 344 {
 345         unsigned long ret;
 346
 347         __asm__ __volatile__ (
 348                 ".section __ex_table,#alloc\n\t"
 349                 ".align 4\n\t"
 350                 ".word 1f,3\n\t"
 351                 ".previous\n\t"
 352                 "mov %2, %%o1\n"
 353                 "1:\n\t"
 354                 "call __bzero\n\t"
 355                 " mov %1, %%o0\n\t"
 356                 "mov %%o0, %0\n"
 357                 : "=r" (ret) : "r" (addr), "r" (size) :
 358                 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
 359                 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
 360
 361         return ret;
 362 }
 363
 364 static inline unsigned long clear_user(void __user *addr, unsigned long n)
 365 {
 366         if (n && __access_ok((unsigned long) addr, n))
 367                 return __clear_user(addr, n);
 368         else
 369                 return n;
 370 }
 371
 372 __must_check long strlen_user(const char __user *str);
 373 __must_check long strnlen_user(const char __user *str, long n);
 374
 375 #endif  /* __ASSEMBLY__ */
 376
 377 #endif /* _ASM_UACCESS_H */