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 extern long not_a_user_address;
  87 #define check_user_ptr(x) \
  88         (void) ({ void __user * __userptr = (__typeof__(*(x)) *)&not_a_user_address; __userptr; })
  89
  90 /* Uh, these should become the main single-value transfer routines..
  91  * They automatically use the right size if we just have the right
  92  * pointer type..
  93  *
  94  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  95  * and yet we don't want to do any pointers, because that is too much
  96  * of a performance impact. Thus we have a few rather ugly macros here,
  97  * and hide all the ugliness from the user.
  98  */
  99 #define put_user(x,ptr) ({ \
 100 unsigned long __pu_addr = (unsigned long)(ptr); \
 101 check_user_ptr(ptr); \
 102 __put_user_check((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); })
 103
 104 #define get_user(x,ptr) ({ \
 105 unsigned long __gu_addr = (unsigned long)(ptr); \
 106 check_user_ptr(ptr); \
 107 __get_user_check((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); })
 108
 109 /*
 110  * The "__xxx" versions do not do address space checking, useful when
 111  * doing multiple accesses to the same area (the user has to do the
 112  * checks by hand with "access_ok()")
 113  */
 114 #define __put_user(x,ptr) __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 115 #define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)),__typeof__(*(ptr)))
 116
 117 struct __large_struct { unsigned long buf[100]; };
 118 #define __m(x) ((struct __large_struct *)(x))
 119
 120 #define __put_user_check(x,addr,size) ({ \
 121 register int __pu_ret; \
 122 if (__access_ok(addr,size)) { \
 123 switch (size) { \
 124 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
 125 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
 126 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
 127 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
 128 default: __pu_ret = __put_user_bad(); break; \
 129 } } else { __pu_ret = -EFAULT; } __pu_ret; })
 130
 131 #define __put_user_check_ret(x,addr,size,retval) ({ \
 132 register int __foo __asm__ ("l1"); \
 133 if (__access_ok(addr,size)) { \
 134 switch (size) { \
 135 case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
 136 case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
 137 case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
 138 case 8: __put_user_asm_ret(x,d,addr,retval,__foo); break; \
 139 default: if (__put_user_bad()) return retval; break; \
 140 } } else return retval; })
 141
 142 #define __put_user_nocheck(x,addr,size) ({ \
 143 register int __pu_ret; \
 144 switch (size) { \
 145 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \
 146 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \
 147 case 4: __put_user_asm(x,,addr,__pu_ret); break; \
 148 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \
 149 default: __pu_ret = __put_user_bad(); break; \
 150 } __pu_ret; })
 151
 152 #define __put_user_nocheck_ret(x,addr,size,retval) ({ \
 153 register int __foo __asm__ ("l1"); \
 154 switch (size) { \
 155 case 1: __put_user_asm_ret(x,b,addr,retval,__foo); break; \
 156 case 2: __put_user_asm_ret(x,h,addr,retval,__foo); break; \
 157 case 4: __put_user_asm_ret(x,,addr,retval,__foo); break; \
 158 case 8: __put_user_asm_ret(x,d,addr,retval,__foo); break; \
 159 default: if (__put_user_bad()) return retval; break; \
 160 } })
 161
 162 #define __put_user_asm(x,size,addr,ret)                                 \
 163 __asm__ __volatile__(                                                   \
 164         "/* Put user asm, inline. */\n"                                 \
 165 "1:\t"  "st"#size " %1, %2\n\t"                                         \
 166         "clr    %0\n"                                                   \
 167 "2:\n\n\t"                                                              \
 168         ".section .fixup,#alloc,#execinstr\n\t"                         \
 169         ".align 4\n"                                                    \
 170 "3:\n\t"                                                                \
 171         "b      2b\n\t"                                                 \
 172         " mov   %3, %0\n\t"                                             \
 173         ".previous\n\n\t"                                               \
 174         ".section __ex_table,#alloc\n\t"                                \
 175         ".align 4\n\t"                                                  \
 176         ".word  1b, 3b\n\t"                                             \
 177         ".previous\n\n\t"                                               \
 178        : "=&r" (ret) : "r" (x), "m" (*__m(addr)),                       \
 179          "i" (-EFAULT))
 180
 181 #define __put_user_asm_ret(x,size,addr,ret,foo)                         \
 182 if (__builtin_constant_p(ret) && ret == -EFAULT)                        \
 183 __asm__ __volatile__(                                                   \
 184         "/* Put user asm ret, inline. */\n"                             \
 185 "1:\t"  "st"#size " %1, %2\n\n\t"                                       \
 186         ".section __ex_table,#alloc\n\t"                                \
 187         ".align 4\n\t"                                                  \
 188         ".word  1b, __ret_efault\n\n\t"                                 \
 189         ".previous\n\n\t"                                               \
 190        : "=r" (foo) : "r" (x), "m" (*__m(addr)));                       \
 191 else                                                                    \
 192 __asm__ __volatile(                                                     \
 193         "/* Put user asm ret, inline. */\n"                             \
 194 "1:\t"  "st"#size " %1, %2\n\n\t"                                       \
 195         ".section .fixup,#alloc,#execinstr\n\t"                         \
 196         ".align 4\n"                                                    \
 197 "3:\n\t"                                                                \
 198         "ret\n\t"                                                       \
 199         " restore %%g0, %3, %%o0\n\t"                                   \
 200         ".previous\n\n\t"                                               \
 201         ".section __ex_table,#alloc\n\t"                                \
 202         ".align 4\n\t"                                                  \
 203         ".word  1b, 3b\n\n\t"                                           \
 204         ".previous\n\n\t"                                               \
 205        : "=r" (foo) : "r" (x), "m" (*__m(addr)), "i" (ret))
 206
 207 extern int __put_user_bad(void);
 208
 209 #define __get_user_check(x,addr,size,type) ({ \
 210 register int __gu_ret; \
 211 register unsigned long __gu_val; \
 212 if (__access_ok(addr,size)) { \
 213 switch (size) { \
 214 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
 215 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
 216 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
 217 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
 218 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
 219 } } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; })
 220
 221 #define __get_user_check_ret(x,addr,size,type,retval) ({ \
 222 register unsigned long __gu_val __asm__ ("l1"); \
 223 if (__access_ok(addr,size)) { \
 224 switch (size) { \
 225 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
 226 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
 227 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
 228 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
 229 default: if (__get_user_bad()) return retval; \
 230 } x = (type) __gu_val; } else return retval; })
 231
 232 #define __get_user_nocheck(x,addr,size,type) ({ \
 233 register int __gu_ret; \
 234 register unsigned long __gu_val; \
 235 switch (size) { \
 236 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
 237 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
 238 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \
 239 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \
 240 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
 241 } x = (type) __gu_val; __gu_ret; })
 242
 243 #define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \
 244 register unsigned long __gu_val __asm__ ("l1"); \
 245 switch (size) { \
 246 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
 247 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
 248 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \
 249 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \
 250 default: if (__get_user_bad()) return retval; \
 251 } x = (type) __gu_val; })
 252
 253 #define __get_user_asm(x,size,addr,ret)                                 \
 254 __asm__ __volatile__(                                                   \
 255         "/* Get user asm, inline. */\n"                                 \
 256 "1:\t"  "ld"#size " %2, %1\n\t"                                         \
 257         "clr    %0\n"                                                   \
 258 "2:\n\n\t"                                                              \
 259         ".section .fixup,#alloc,#execinstr\n\t"                         \
 260         ".align 4\n"                                                    \
 261 "3:\n\t"                                                                \
 262         "clr    %1\n\t"                                                 \
 263         "b      2b\n\t"                                                 \
 264         " mov   %3, %0\n\n\t"                                           \
 265         ".previous\n\t"                                                 \
 266         ".section __ex_table,#alloc\n\t"                                \
 267         ".align 4\n\t"                                                  \
 268         ".word  1b, 3b\n\n\t"                                           \
 269         ".previous\n\t"                                                 \
 270        : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)),                     \
 271          "i" (-EFAULT))
 272
 273 #define __get_user_asm_ret(x,size,addr,retval)                          \
 274 if (__builtin_constant_p(retval) && retval == -EFAULT)                  \
 275 __asm__ __volatile__(                                                   \
 276         "/* Get user asm ret, inline. */\n"                             \
 277 "1:\t"  "ld"#size " %1, %0\n\n\t"                                       \
 278         ".section __ex_table,#alloc\n\t"                                \
 279         ".align 4\n\t"                                                  \
 280         ".word  1b,__ret_efault\n\n\t"                                  \
 281         ".previous\n\t"                                                 \
 282        : "=&r" (x) : "m" (*__m(addr)));                                 \
 283 else                                                                    \
 284 __asm__ __volatile__(                                                   \
 285         "/* Get user asm ret, inline. */\n"                             \
 286 "1:\t"  "ld"#size " %1, %0\n\n\t"                                       \
 287         ".section .fixup,#alloc,#execinstr\n\t"                         \
 288         ".align 4\n"                                                    \
 289 "3:\n\t"                                                                \
 290         "ret\n\t"                                                       \
 291         " restore %%g0, %2, %%o0\n\n\t"                                 \
 292         ".previous\n\t"                                                 \
 293         ".section __ex_table,#alloc\n\t"                                \
 294         ".align 4\n\t"                                                  \
 295         ".word  1b, 3b\n\n\t"                                           \
 296         ".previous\n\t"                                                 \
 297        : "=&r" (x) : "m" (*__m(addr)), "i" (retval))
 298
 299 extern int __get_user_bad(void);
 300
 301 extern unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
 302
 303 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
 304 {
 305         if (n && __access_ok((unsigned long) to, n))
 306                 return __copy_user(to, (void __user *) from, n);
 307         else
 308                 return n;
 309 }
 310
 311 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
 312 {
 313         return __copy_user(to, (void __user *) from, n);
 314 }
 315
 316 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 317 {
 318         if (n && __access_ok((unsigned long) from, n))
 319                 return __copy_user((void __user *) to, from, n);
 320         else
 321                 return n;
 322 }
 323
 324 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
 325 {
 326         return __copy_user((void __user *) to, from, n);
 327 }
 328
 329 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
 330 {
 331         unsigned long ret;
 332
 333         __asm__ __volatile__ (
 334                 ".section __ex_table,#alloc\n\t"
 335                 ".align 4\n\t"
 336                 ".word 1f,3\n\t"
 337                 ".previous\n\t"
 338                 "mov %2, %%o1\n"
 339                 "1:\n\t"
 340                 "call __bzero\n\t"
 341                 " mov %1, %%o0\n\t"
 342                 "mov %%o0, %0\n"
 343                 : "=r" (ret) : "r" (addr), "r" (size) :
 344                 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
 345                 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
 346
 347         return ret;
 348 }
 349
 350 static inline unsigned long clear_user(void __user *addr, unsigned long n)
 351 {
 352         if (n && __access_ok((unsigned long) addr, n))
 353                 return __clear_user(addr, n);
 354         else
 355                 return n;
 356 }
 357
 358 extern long __strncpy_from_user(char *dest, const char __user *src, long count);
 359
 360 static inline long strncpy_from_user(char *dest, const char __user *src, long count)
 361 {
 362         if (__access_ok((unsigned long) src, count))
 363                 return __strncpy_from_user(dest, src, count);
 364         else
 365                 return -EFAULT;
 366 }
 367
 368 extern long __strlen_user(const char __user *);
 369 extern long __strnlen_user(const char __user *, long len);
 370
 371 static inline long strlen_user(const char __user *str)
 372 {
 373         if (!access_ok(VERIFY_READ, str, 0))
 374                 return 0;
 375         else
 376                 return __strlen_user(str);
 377 }
 378
 379 static inline long strnlen_user(const char __user *str, long len)
 380 {
 381         if (!access_ok(VERIFY_READ, str, 0))
 382                 return 0;
 383         else
 384                 return __strnlen_user(str, len);
 385 }
 386
 387 #endif  /* __ASSEMBLY__ */
 388
 389 #endif /* _ASM_UACCESS_H */