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 #endif
  16
  17 #ifndef __ASSEMBLY__
  18
  19 #include <asm/processor.h>
  20
  21 #define ARCH_HAS_SORT_EXTABLE
  22 #define ARCH_HAS_SEARCH_EXTABLE
  23
  24 /* Sparc is not segmented, however we need to be able to fool access_ok()
  25  * when doing system calls from kernel mode legitimately.
  26  *
  27  * "For historical reasons, these macros are grossly misnamed." -Linus
  28  */
  29
  30 #define KERNEL_DS   ((mm_segment_t) { 0 })
  31 #define USER_DS     ((mm_segment_t) { -1 })
  32
  33 #define VERIFY_READ     0
  34 #define VERIFY_WRITE    1
  35
  36 #define get_ds()        (KERNEL_DS)
  37 #define get_fs()        (current->thread.current_ds)
  38 #define set_fs(val)     ((current->thread.current_ds) = (val))
  39
  40 #define segment_eq(a, b) ((a).seg == (b).seg)
  41
  42 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
  43  * can be fairly lightweight.
  44  * No one can read/write anything from userland in the kernel space by setting
  45  * large size and address near to PAGE_OFFSET - a fault will break his intentions.
  46  */
  47 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
  48 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
  49 #define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size)))
  50 #define access_ok(type, addr, size) \
  51         ({ (void)(type); __access_ok((unsigned long)(addr), size); })
  52
  53 /*
  54  * The exception table consists of pairs of addresses: the first is the
  55  * address of an instruction that is allowed to fault, and the second is
  56  * the address at which the program should continue.  No registers are
  57  * modified, so it is entirely up to the continuation code to figure out
  58  * what to do.
  59  *
  60  * All the routines below use bits of fixup code that are out of line
  61  * with the main instruction path.  This means when everything is well,
  62  * we don't even have to jump over them.  Further, they do not intrude
  63  * on our cache or tlb entries.
  64  *
  65  * There is a special way how to put a range of potentially faulting
  66  * insns (like twenty ldd/std's with now intervening other instructions)
  67  * You specify address of first in insn and 0 in fixup and in the next
  68  * exception_table_entry you specify last potentially faulting insn + 1
  69  * and in fixup the routine which should handle the fault.
  70  * That fixup code will get
  71  * (faulting_insn_address - first_insn_in_the_range_address)/4
  72  * in %g2 (ie. index of the faulting instruction in the range).
  73  */
  74
  75 struct exception_table_entry
  76 {
  77         unsigned long insn, fixup;
  78 };
  79
  80 /* Returns 0 if exception not found and fixup otherwise.  */
  81 unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
  82
  83 void __ret_efault(void);
  84
  85 /* Uh, these should become the main single-value transfer routines..
  86  * They automatically use the right size if we just have the right
  87  * pointer type..
  88  *
  89  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  90  * and yet we don't want to do any pointers, because that is too much
  91  * of a performance impact. Thus we have a few rather ugly macros here,
  92  * and hide all the ugliness from the user.
  93  */
  94 #define put_user(x, ptr) ({ \
  95         unsigned long __pu_addr = (unsigned long)(ptr); \
  96         __chk_user_ptr(ptr); \
  97         __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \
  98 })
  99
 100 #define get_user(x, ptr) ({ \
 101         unsigned long __gu_addr = (unsigned long)(ptr); \
 102         __chk_user_ptr(ptr); \
 103         __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \
 104 })
 105
 106 /*
 107  * The "__xxx" versions do not do address space checking, useful when
 108  * doing multiple accesses to the same area (the user has to do the
 109  * checks by hand with "access_ok()")
 110  */
 111 #define __put_user(x, ptr) \
 112         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 113 #define __get_user(x, ptr) \
 114     __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr)))
 115
 116 struct __large_struct { unsigned long buf[100]; };
 117 #define __m(x) ((struct __large_struct __user *)(x))
 118
 119 #define __put_user_check(x, addr, size) ({ \
 120         register int __pu_ret; \
 121         if (__access_ok(addr, size)) { \
 122                 switch (size) { \
 123                 case 1: \
 124                         __put_user_asm(x, b, addr, __pu_ret); \
 125                         break; \
 126                 case 2: \
 127                         __put_user_asm(x, h, addr, __pu_ret); \
 128                         break; \
 129                 case 4: \
 130                         __put_user_asm(x, , addr, __pu_ret); \
 131                         break; \
 132                 case 8: \
 133                         __put_user_asm(x, d, addr, __pu_ret); \
 134                         break; \
 135                 default: \
 136                         __pu_ret = __put_user_bad(); \
 137                         break; \
 138                 } \
 139         } else { \
 140                 __pu_ret = -EFAULT; \
 141         } \
 142         __pu_ret; \
 143 })
 144
 145 #define __put_user_nocheck(x, addr, size) ({                    \
 146         register int __pu_ret;                                  \
 147         switch (size) {                                         \
 148         case 1: __put_user_asm(x, b, addr, __pu_ret); break;    \
 149         case 2: __put_user_asm(x, h, addr, __pu_ret); break;    \
 150         case 4: __put_user_asm(x, , addr, __pu_ret); break;     \
 151         case 8: __put_user_asm(x, d, addr, __pu_ret); break;    \
 152         default: __pu_ret = __put_user_bad(); break;            \
 153         } \
 154         __pu_ret; \
 155 })
 156
 157 #define __put_user_asm(x, size, addr, ret)                              \
 158 __asm__ __volatile__(                                                   \
 159                 "/* Put user asm, inline. */\n"                         \
 160         "1:\t"  "st"#size " %1, %2\n\t"                                 \
 161                 "clr    %0\n"                                           \
 162         "2:\n\n\t"                                                      \
 163                 ".section .fixup,#alloc,#execinstr\n\t"                 \
 164                 ".align 4\n"                                            \
 165         "3:\n\t"                                                        \
 166                 "b      2b\n\t"                                         \
 167                 " mov   %3, %0\n\t"                                     \
 168                 ".previous\n\n\t"                                       \
 169                 ".section __ex_table,#alloc\n\t"                        \
 170                 ".align 4\n\t"                                          \
 171                 ".word  1b, 3b\n\t"                                     \
 172                 ".previous\n\n\t"                                       \
 173                : "=&r" (ret) : "r" (x), "m" (*__m(addr)),               \
 174                  "i" (-EFAULT))
 175
 176 int __put_user_bad(void);
 177
 178 #define __get_user_check(x, addr, size, type) ({ \
 179         register int __gu_ret; \
 180         register unsigned long __gu_val; \
 181         if (__access_ok(addr, size)) { \
 182                 switch (size) { \
 183                 case 1: \
 184                          __get_user_asm(__gu_val, ub, addr, __gu_ret); \
 185                         break; \
 186                 case 2: \
 187                         __get_user_asm(__gu_val, uh, addr, __gu_ret); \
 188                         break; \
 189                 case 4: \
 190                         __get_user_asm(__gu_val, , addr, __gu_ret); \
 191                         break; \
 192                 case 8: \
 193                         __get_user_asm(__gu_val, d, addr, __gu_ret); \
 194                         break; \
 195                 default: \
 196                         __gu_val = 0; \
 197                         __gu_ret = __get_user_bad(); \
 198                         break; \
 199                 } \
 200          } else { \
 201                  __gu_val = 0; \
 202                  __gu_ret = -EFAULT; \
 203         } \
 204         x = (__force type) __gu_val; \
 205         __gu_ret; \
 206 })
 207
 208 #define __get_user_nocheck(x, addr, size, type) ({                      \
 209         register int __gu_ret;                                          \
 210         register unsigned long __gu_val;                                \
 211         switch (size) {                                                 \
 212         case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break;    \
 213         case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break;    \
 214         case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break;      \
 215         case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break;     \
 216         default:                                                        \
 217                 __gu_val = 0;                                           \
 218                 __gu_ret = __get_user_bad();                            \
 219                 break;                                                  \
 220         }                                                               \
 221         x = (__force type) __gu_val;                                    \
 222         __gu_ret;                                                       \
 223 })
 224
 225 #define __get_user_asm(x, size, addr, ret)                              \
 226 __asm__ __volatile__(                                                   \
 227                 "/* Get user asm, inline. */\n"                         \
 228         "1:\t"  "ld"#size " %2, %1\n\t"                                 \
 229                 "clr    %0\n"                                           \
 230         "2:\n\n\t"                                                      \
 231                 ".section .fixup,#alloc,#execinstr\n\t"                 \
 232                 ".align 4\n"                                            \
 233         "3:\n\t"                                                        \
 234                 "clr    %1\n\t"                                         \
 235                 "b      2b\n\t"                                         \
 236                 " mov   %3, %0\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" (ret), "=&r" (x) : "m" (*__m(addr)),             \
 243                  "i" (-EFAULT))
 244
 245 int __get_user_bad(void);
 246
 247 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
 248
 249 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
 250 {
 251         if (n && __access_ok((unsigned long) to, n)) {
 252                 check_object_size(from, n, true);
 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         check_object_size(from, n, true);
 261         return __copy_user(to, (__force void __user *) from, n);
 262 }
 263
 264 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 265 {
 266         if (n && __access_ok((unsigned long) from, n)) {
 267                 check_object_size(to, n, false);
 268                 return __copy_user((__force void __user *) to, from, n);
 269         } else {
 270                 memset(to, 0, n);
 271                 return n;
 272         }
 273 }
 274
 275 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
 276 {
 277         return __copy_user((__force void __user *) to, from, n);
 278 }
 279
 280 #define __copy_to_user_inatomic __copy_to_user
 281 #define __copy_from_user_inatomic __copy_from_user
 282
 283 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
 284 {
 285         unsigned long ret;
 286
 287         __asm__ __volatile__ (
 288                 ".section __ex_table,#alloc\n\t"
 289                 ".align 4\n\t"
 290                 ".word 1f,3\n\t"
 291                 ".previous\n\t"
 292                 "mov %2, %%o1\n"
 293                 "1:\n\t"
 294                 "call __bzero\n\t"
 295                 " mov %1, %%o0\n\t"
 296                 "mov %%o0, %0\n"
 297                 : "=r" (ret) : "r" (addr), "r" (size) :
 298                 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
 299                 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
 300
 301         return ret;
 302 }
 303
 304 static inline unsigned long clear_user(void __user *addr, unsigned long n)
 305 {
 306         if (n && __access_ok((unsigned long) addr, n))
 307                 return __clear_user(addr, n);
 308         else
 309                 return n;
 310 }
 311
 312 __must_check long strlen_user(const char __user *str);
 313 __must_check long strnlen_user(const char __user *str, long n);
 314
 315 #endif  /* __ASSEMBLY__ */
 316
 317 #endif /* _ASM_UACCESS_H */