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_nocheck(x,addr,size) ({ \
 124 register int __pu_ret; \
 125 switch (size) { \
 126 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
 127 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
 128 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
 129 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
 130 default: __pu_ret = __put_user_bad(); break; \
 131 } __pu_ret; })
 132
 133 #define __put_user_asm(x,size,addr,ret)                                 \
 134 __asm__ __volatile__(                                                   \
 135         "/* Put user asm, inline. */\n"                                 \
 136 "1:\t"  "st"#size " %1, %2\n\t"                                         \
 137         "clr    %0\n"                                                   \
 138 "2:\n\n\t"                                                              \
 139         ".section .fixup,#alloc,#execinstr\n\t"                         \
 140         ".align 4\n"                                                    \
 141 "3:\n\t"                                                                \
 142         "b      2b\n\t"                                                 \
 143         " mov   %3, %0\n\t"                                             \
 144         ".previous\n\n\t"                                               \
 145         ".section __ex_table,#alloc\n\t"                                \
 146         ".align 4\n\t"                                                  \
 147         ".word  1b, 3b\n\t"                                             \
 148         ".previous\n\n\t"                                               \
 149        : "=&r" (ret) : "r" (x), "m" (*__m(addr)),                       \
 150          "i" (-EFAULT))
 151
 152 extern int __put_user_bad(void);
 153
 154 #define __get_user_check(x,addr,size,type) ({ \
 155 register int __gu_ret; \
 156 register unsigned long __gu_val; \
 157 if (__access_ok(addr,size)) { \
 158 switch (size) { \
 159 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
 160 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
 161 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
 162 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
 163 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
 164 } } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; })
 165
 166 #define __get_user_check_ret(x,addr,size,type,retval) ({ \
 167 register unsigned long __gu_val __asm__ ("l1"); \
 168 if (__access_ok(addr,size)) { \
 169 switch (size) { \
 170 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
 171 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
 172 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
 173 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
 174 default: if (__get_user_bad()) return retval; \
 175 } x = (type) __gu_val; } else return retval; })
 176
 177 #define __get_user_nocheck(x,addr,size,type) ({ \
 178 register int __gu_ret; \
 179 register unsigned long __gu_val; \
 180 switch (size) { \
 181 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
 182 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
 183 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
 184 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
 185 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
 186 } x = (type) __gu_val; __gu_ret; })
 187
 188 #define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \
 189 register unsigned long __gu_val __asm__ ("l1"); \
 190 switch (size) { \
 191 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
 192 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
 193 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
 194 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
 195 default: if (__get_user_bad()) return retval; \
 196 } x = (type) __gu_val; })
 197
 198 #define __get_user_asm(x,size,addr,ret)                                 \
 199 __asm__ __volatile__(                                                   \
 200         "/* Get user asm, inline. */\n"                                 \
 201 "1:\t"  "ld"#size " %2, %1\n\t"                                         \
 202         "clr    %0\n"                                                   \
 203 "2:\n\n\t"                                                              \
 204         ".section .fixup,#alloc,#execinstr\n\t"                         \
 205         ".align 4\n"                                                    \
 206 "3:\n\t"                                                                \
 207         "clr    %1\n\t"                                                 \
 208         "b      2b\n\t"                                                 \
 209         " mov   %3, %0\n\n\t"                                           \
 210         ".previous\n\t"                                                 \
 211         ".section __ex_table,#alloc\n\t"                                \
 212         ".align 4\n\t"                                                  \
 213         ".word  1b, 3b\n\n\t"                                           \
 214         ".previous\n\t"                                                 \
 215        : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)),                     \
 216          "i" (-EFAULT))
 217
 218 #define __get_user_asm_ret(x,size,addr,retval)                          \
 219 if (__builtin_constant_p(retval) && retval == -EFAULT)                  \
 220 __asm__ __volatile__(                                                   \
 221         "/* Get user asm ret, inline. */\n"                             \
 222 "1:\t"  "ld"#size " %1, %0\n\n\t"                                       \
 223         ".section __ex_table,#alloc\n\t"                                \
 224         ".align 4\n\t"                                                  \
 225         ".word  1b,__ret_efault\n\n\t"                                  \
 226         ".previous\n\t"                                                 \
 227        : "=&r" (x) : "m" (*__m(addr)));                                 \
 228 else                                                                    \
 229 __asm__ __volatile__(                                                   \
 230         "/* Get user asm ret, inline. */\n"                             \
 231 "1:\t"  "ld"#size " %1, %0\n\n\t"                                       \
 232         ".section .fixup,#alloc,#execinstr\n\t"                         \
 233         ".align 4\n"                                                    \
 234 "3:\n\t"                                                                \
 235         "ret\n\t"                                                       \
 236         " restore %%g0, %2, %%o0\n\n\t"                                 \
 237         ".previous\n\t"                                                 \
 238         ".section __ex_table,#alloc\n\t"                                \
 239         ".align 4\n\t"                                                  \
 240         ".word  1b, 3b\n\n\t"                                           \
 241         ".previous\n\t"                                                 \
 242        : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
 243
 244 extern int __get_user_bad(void);
 245
 246 extern unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
 247
 248 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
 249 {
 250         if (n && __access_ok((unsigned long) to, n))
 251                 return __copy_user(to, (__force void __user *) from, n);
 252         else
 253                 return n;
 254 }
 255
 256 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
 257 {
 258         return __copy_user(to, (__force void __user *) from, n);
 259 }
 260
 261 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 262 {
 263         if (n && __access_ok((unsigned long) from, n))
 264                 return __copy_user((__force void __user *) to, from, n);
 265         else
 266                 return n;
 267 }
 268
 269 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
 270 {
 271         return __copy_user((__force void __user *) to, from, n);
 272 }
 273
 274 #define __copy_to_user_inatomic __copy_to_user
 275 #define __copy_from_user_inatomic __copy_from_user
 276
 277 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
 278 {
 279         unsigned long ret;
 280
 281         __asm__ __volatile__ (
 282                 ".section __ex_table,#alloc\n\t"
 283                 ".align 4\n\t"
 284                 ".word 1f,3\n\t"
 285                 ".previous\n\t"
 286                 "mov %2, %%o1\n"
 287                 "1:\n\t"
 288                 "call __bzero\n\t"
 289                 " mov %1, %%o0\n\t"
 290                 "mov %%o0, %0\n"
 291                 : "=r" (ret) : "r" (addr), "r" (size) :
 292                 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
 293                 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
 294
 295         return ret;
 296 }
 297
 298 static inline unsigned long clear_user(void __user *addr, unsigned long n)
 299 {
 300         if (n && __access_ok((unsigned long) addr, n))
 301                 return __clear_user(addr, n);
 302         else
 303                 return n;
 304 }
 305
 306 extern long __strncpy_from_user(char *dest, const char __user *src, long count);
 307
 308 static inline long strncpy_from_user(char *dest, const char __user *src, long count)
 309 {
 310         if (__access_ok((unsigned long) src, count))
 311                 return __strncpy_from_user(dest, src, count);
 312         else
 313                 return -EFAULT;
 314 }
 315
 316 extern long __strlen_user(const char __user *);
 317 extern long __strnlen_user(const char __user *, long len);
 318
 319 static inline long strlen_user(const char __user *str)
 320 {
 321         if (!access_ok(VERIFY_READ, str, 0))
 322                 return 0;
 323         else
 324                 return __strlen_user(str);
 325 }
 326
 327 static inline long strnlen_user(const char __user *str, long len)
 328 {
 329         if (!access_ok(VERIFY_READ, str, 0))
 330                 return 0;
 331         else
 332                 return __strnlen_user(str, len);
 333 }
 334
 335 #endif  /* __ASSEMBLY__ */
 336
 337 #endif /* _ASM_UACCESS_H */