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