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