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