include/asm-sparc/uaccess.h

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