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   1 /* $Id: uaccess.h,v 1.24 2001/10/30 04:32:24 davem Exp $
   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 #include <asm/vac-ops.h>
  16 #include <asm/a.out.h>
  17 #endif
  18
  19 #ifndef __ASSEMBLY__
  20
  21 /* Sparc is not segmented, however we need to be able to fool access_ok()
  22  * when doing system calls from kernel mode legitimately.
  23  *
  24  * "For historical reasons, these macros are grossly misnamed." -Linus
  25  */
  26
  27 #define KERNEL_DS   ((mm_segment_t) { 0 })
  28 #define USER_DS     ((mm_segment_t) { -1 })
  29
  30 #define VERIFY_READ     0
  31 #define VERIFY_WRITE    1
  32
  33 #define get_ds()        (KERNEL_DS)
  34 #define get_fs()        (current->thread.current_ds)
  35 #define set_fs(val)     ((current->thread.current_ds) = (val))
  36
  37 #define segment_eq(a,b) ((a).seg == (b).seg)
  38
  39 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
  40  * can be fairly lightweight.
  41  * No one can read/write anything from userland in the kernel space by setting
  42  * large size and address near to PAGE_OFFSET - a fault will break his intentions.
  43  */
  44 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
  45 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
  46 #define __access_ok(addr,size) (__user_ok((addr) & get_fs().seg,(size)))
  47 #define access_ok(type, addr, size)                                     \
  48         ({ (void)(type); __access_ok((unsigned long)(addr), size); })
  49
  50 /* this function will go away soon - use access_ok() instead */
  51 static inline int __deprecated verify_area(int type, const void __user * addr, unsigned long size)
  52 {
  53         return access_ok(type,addr,size) ? 0 : -EFAULT;
  54 }
  55
  56 /*
  57  * The exception table consists of pairs of addresses: the first is the
  58  * address of an instruction that is allowed to fault, and the second is
  59  * the address at which the program should continue.  No registers are
  60  * modified, so it is entirely up to the continuation code to figure out
  61  * what to do.
  62  *
  63  * All the routines below use bits of fixup code that are out of line
  64  * with the main instruction path.  This means when everything is well,
  65  * we don't even have to jump over them.  Further, they do not intrude
  66  * on our cache or tlb entries.
  67  *
  68  * There is a special way how to put a range of potentially faulting
  69  * insns (like twenty ldd/std's with now intervening other instructions)
  70  * You specify address of first in insn and 0 in fixup and in the next
  71  * exception_table_entry you specify last potentially faulting insn + 1
  72  * and in fixup the routine which should handle the fault.
  73  * That fixup code will get
  74  * (faulting_insn_address - first_insn_in_the_range_address)/4
  75  * in %g2 (ie. index of the faulting instruction in the range).
  76  */
  77
  78 struct exception_table_entry
  79 {
  80         unsigned long insn, fixup;
  81 };
  82
  83 /* Returns 0 if exception not found and fixup otherwise.  */
  84 extern unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
  85
  86 extern void __ret_efault(void);
  87
  88 /* Uh, these should become the main single-value transfer routines..
  89  * They automatically use the right size if we just have the right
  90  * pointer type..
  91  *
  92  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  93  * and yet we don't want to do any pointers, because that is too much
  94  * of a performance impact. Thus we have a few rather ugly macros here,
  95  * and hide all the ugliness from the user.
  96  */
  97 #define put_user(x,ptr) ({ \
  98 unsigned long __pu_addr = (unsigned long)(ptr); \
  99 __chk_user_ptr(ptr); \
 100 __put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); })
 101
 102 #define get_user(x,ptr) ({ \
 103 unsigned long __gu_addr = (unsigned long)(ptr); \
 104 __chk_user_ptr(ptr); \
 105 __get_user_check((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); })
 106
 107 /*
 108  * The "__xxx" versions do not do address space checking, useful when
 109  * doing multiple accesses to the same area (the user has to do the
 110  * checks by hand with "access_ok()")
 111  */
 112 #define __put_user(x,ptr) __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 113 #define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)),__typeof__(*(ptr)))
 114
 115 struct __large_struct { unsigned long buf[100]; };
 116 #define __m(x) ((struct __large_struct __user *)(x))
 117
 118 #define __put_user_check(x,addr,size) ({ \
 119 register int __pu_ret; \
 120 if (__access_ok(addr,size)) { \
 121 switch (size) { \
 122 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
 123 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
 124 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
 125 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
 126 default: __pu_ret = __put_user_bad(); break; \
 127 } } else { __pu_ret = -EFAULT; } __pu_ret; })
 128
 129 #define __put_user_check_ret(x,addr,size,retval) ({ \
 130 register int __foo __asm__ ("l1"); \
 131 if (__access_ok(addr,size)) { \
 132 switch (size) { \
 133 case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
 134 case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
 135 case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
 136 case 8: __put_user_asm_ret(x,d,addr,retval,__foo); break; \
 137 default: if (__put_user_bad()) return retval; break; \
 138 } } else return retval; })
 139
 140 #define __put_user_nocheck(x,addr,size) ({ \
 141 register int __pu_ret; \
 142 switch (size) { \
 143 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
 144 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
 145 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
 146 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
 147 default: __pu_ret = __put_user_bad(); break; \
 148 } __pu_ret; })
 149
 150 #define __put_user_nocheck_ret(x,addr,size,retval) ({ \
 151 register int __foo __asm__ ("l1"); \
 152 switch (size) { \
 153 case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
 154 case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
 155 case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
 156 case 8: __put_user_asm_ret(x,d,addr,retval,__foo); break; \
 157 default: if (__put_user_bad()) return retval; break; \
 158 } })
 159
 160 #define __put_user_asm(x,size,addr,ret)                                 \
 161 __asm__ __volatile__(                                                   \
 162         "/* Put user asm, inline. */\n"                                 \
 163 "1:\t"  "st"#size " %1, %2\n\t"                                         \
 164         "clr    %0\n"                                                   \
 165 "2:\n\n\t"                                                              \
 166         ".section .fixup,#alloc,#execinstr\n\t"                         \
 167         ".align 4\n"                                                    \
 168 "3:\n\t"                                                                \
 169         "b      2b\n\t"                                                 \
 170         " mov   %3, %0\n\t"                                             \
 171         ".previous\n\n\t"                                               \
 172         ".section __ex_table,#alloc\n\t"                                \
 173         ".align 4\n\t"                                                  \
 174         ".word  1b, 3b\n\t"                                             \
 175         ".previous\n\n\t"                                               \
 176        : "=&r" (ret) : "r" (x), "m" (*__m(addr)),                       \
 177          "i" (-EFAULT))
 178
 179 #define __put_user_asm_ret(x,size,addr,ret,foo)                         \
 180 if (__builtin_constant_p(ret) && ret == -EFAULT)                        \
 181 __asm__ __volatile__(                                                   \
 182         "/* Put user asm ret, inline. */\n"                             \
 183 "1:\t"  "st"#size " %1, %2\n\n\t"                                       \
 184         ".section __ex_table,#alloc\n\t"                                \
 185         ".align 4\n\t"                                                  \
 186         ".word  1b, __ret_efault\n\n\t"                                 \
 187         ".previous\n\n\t"                                               \
 188        : "=r" (foo) : "r" (x), "m" (*__m(addr)));                       \
 189 else                                                                    \
 190 __asm__ __volatile(                                                     \
 191         "/* Put user asm ret, inline. */\n"                             \
 192 "1:\t"  "st"#size " %1, %2\n\n\t"                                       \
 193         ".section .fixup,#alloc,#execinstr\n\t"                         \
 194         ".align 4\n"                                                    \
 195 "3:\n\t"                                                                \
 196         "ret\n\t"                                                       \
 197         " restore %%g0, %3, %%o0\n\t"                                   \
 198         ".previous\n\n\t"                                               \
 199         ".section __ex_table,#alloc\n\t"                                \
 200         ".align 4\n\t"                                                  \
 201         ".word  1b, 3b\n\n\t"                                           \
 202         ".previous\n\n\t"                                               \
 203        : "=r" (foo) : "r" (x), "m" (*__m(addr)), "i" (ret))
 204
 205 extern int __put_user_bad(void);
 206
 207 #define __get_user_check(x,addr,size,type) ({ \
 208 register int __gu_ret; \
 209 register unsigned long __gu_val; \
 210 if (__access_ok(addr,size)) { \
 211 switch (size) { \
 212 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
 213 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
 214 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
 215 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
 216 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
 217 } } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; })
 218
 219 #define __get_user_check_ret(x,addr,size,type,retval) ({ \
 220 register unsigned long __gu_val __asm__ ("l1"); \
 221 if (__access_ok(addr,size)) { \
 222 switch (size) { \
 223 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
 224 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
 225 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
 226 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
 227 default: if (__get_user_bad()) return retval; \
 228 } x = (type) __gu_val; } else return retval; })
 229
 230 #define __get_user_nocheck(x,addr,size,type) ({ \
 231 register int __gu_ret; \
 232 register unsigned long __gu_val; \
 233 switch (size) { \
 234 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
 235 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
 236 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
 237 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
 238 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
 239 } x = (type) __gu_val; __gu_ret; })
 240
 241 #define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \
 242 register unsigned long __gu_val __asm__ ("l1"); \
 243 switch (size) { \
 244 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
 245 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
 246 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
 247 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
 248 default: if (__get_user_bad()) return retval; \
 249 } x = (type) __gu_val; })
 250
 251 #define __get_user_asm(x,size,addr,ret)                                 \
 252 __asm__ __volatile__(                                                   \
 253         "/* Get user asm, inline. */\n"                                 \
 254 "1:\t"  "ld"#size " %2, %1\n\t"                                         \
 255         "clr    %0\n"                                                   \
 256 "2:\n\n\t"                                                              \
 257         ".section .fixup,#alloc,#execinstr\n\t"                         \
 258         ".align 4\n"                                                    \
 259 "3:\n\t"                                                                \
 260         "clr    %1\n\t"                                                 \
 261         "b      2b\n\t"                                                 \
 262         " mov   %3, %0\n\n\t"                                           \
 263         ".previous\n\t"                                                 \
 264         ".section __ex_table,#alloc\n\t"                                \
 265         ".align 4\n\t"                                                  \
 266         ".word  1b, 3b\n\n\t"                                           \
 267         ".previous\n\t"                                                 \
 268        : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)),                     \
 269          "i" (-EFAULT))
 270
 271 #define __get_user_asm_ret(x,size,addr,retval)                          \
 272 if (__builtin_constant_p(retval) && retval == -EFAULT)                  \
 273 __asm__ __volatile__(                                                   \
 274         "/* Get user asm ret, inline. */\n"                             \
 275 "1:\t"  "ld"#size " %1, %0\n\n\t"                                       \
 276         ".section __ex_table,#alloc\n\t"                                \
 277         ".align 4\n\t"                                                  \
 278         ".word  1b,__ret_efault\n\n\t"                                  \
 279         ".previous\n\t"                                                 \
 280        : "=&r" (x) : "m" (*__m(addr)));                                 \
 281 else                                                                    \
 282 __asm__ __volatile__(                                                   \
 283         "/* Get user asm ret, inline. */\n"                             \
 284 "1:\t"  "ld"#size " %1, %0\n\n\t"                                       \
 285         ".section .fixup,#alloc,#execinstr\n\t"                         \
 286         ".align 4\n"                                                    \
 287 "3:\n\t"                                                                \
 288         "ret\n\t"                                                       \
 289         " restore %%g0, %2, %%o0\n\n\t"                                 \
 290         ".previous\n\t"                                                 \
 291         ".section __ex_table,#alloc\n\t"                                \
 292         ".align 4\n\t"                                                  \
 293         ".word  1b, 3b\n\n\t"                                           \
 294         ".previous\n\t"                                                 \
 295        : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
 296
 297 extern int __get_user_bad(void);
 298
 299 extern unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
 300
 301 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
 302 {
 303         if (n && __access_ok((unsigned long) to, n))
 304                 return __copy_user(to, (__force void __user *) from, n);
 305         else
 306                 return n;
 307 }
 308
 309 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
 310 {
 311         return __copy_user(to, (__force void __user *) from, n);
 312 }
 313
 314 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 315 {
 316         if (n && __access_ok((unsigned long) from, n))
 317                 return __copy_user((__force void __user *) to, from, n);
 318         else
 319                 return n;
 320 }
 321
 322 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
 323 {
 324         return __copy_user((__force void __user *) to, from, n);
 325 }
 326
 327 #define __copy_to_user_inatomic __copy_to_user
 328 #define __copy_from_user_inatomic __copy_from_user
 329
 330 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
 331 {
 332         unsigned long ret;
 333
 334         __asm__ __volatile__ (
 335                 ".section __ex_table,#alloc\n\t"
 336                 ".align 4\n\t"
 337                 ".word 1f,3\n\t"
 338                 ".previous\n\t"
 339                 "mov %2, %%o1\n"
 340                 "1:\n\t"
 341                 "call __bzero\n\t"
 342                 " mov %1, %%o0\n\t"
 343                 "mov %%o0, %0\n"
 344                 : "=r" (ret) : "r" (addr), "r" (size) :
 345                 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
 346                 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
 347
 348         return ret;
 349 }
 350
 351 static inline unsigned long clear_user(void __user *addr, unsigned long n)
 352 {
 353         if (n && __access_ok((unsigned long) addr, n))
 354                 return __clear_user(addr, n);
 355         else
 356                 return n;
 357 }
 358
 359 extern long __strncpy_from_user(char *dest, const char __user *src, long count);
 360
 361 static inline long strncpy_from_user(char *dest, const char __user *src, long count)
 362 {
 363         if (__access_ok((unsigned long) src, count))
 364                 return __strncpy_from_user(dest, src, count);
 365         else
 366                 return -EFAULT;
 367 }
 368
 369 extern long __strlen_user(const char __user *);
 370 extern long __strnlen_user(const char __user *, long len);
 371
 372 static inline long strlen_user(const char __user *str)
 373 {
 374         if (!access_ok(VERIFY_READ, str, 0))
 375                 return 0;
 376         else
 377                 return __strlen_user(str);
 378 }
 379
 380 static inline long strnlen_user(const char __user *str, long len)
 381 {
 382         if (!access_ok(VERIFY_READ, str, 0))
 383                 return 0;
 384         else
 385                 return __strnlen_user(str, len);
 386 }
 387
 388 #endif  /* __ASSEMBLY__ */
 389
 390 #endif /* _ASM_UACCESS_H */