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 #include <linux/compiler.h>
  11 #include <linux/string.h>
  12
  13 #include <asm/processor.h>
  14
  15 #define ARCH_HAS_SORT_EXTABLE
  16 #define ARCH_HAS_SEARCH_EXTABLE
  17
  18 /* Sparc is not segmented, however we need to be able to fool access_ok()
  19  * when doing system calls from kernel mode legitimately.
  20  *
  21  * "For historical reasons, these macros are grossly misnamed." -Linus
  22  */
  23
  24 #define KERNEL_DS   ((mm_segment_t) { 0 })
  25 #define USER_DS     ((mm_segment_t) { -1 })
  26
  27 #define get_ds()        (KERNEL_DS)
  28 #define get_fs()        (current->thread.current_ds)
  29 #define set_fs(val)     ((current->thread.current_ds) = (val))
  30
  31 #define segment_eq(a, b) ((a).seg == (b).seg)
  32
  33 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test
  34  * can be fairly lightweight.
  35  * No one can read/write anything from userland in the kernel space by setting
  36  * large size and address near to PAGE_OFFSET - a fault will break his intentions.
  37  */
  38 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
  39 #define __kernel_ok (uaccess_kernel())
  40 #define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size)))
  41 #define access_ok(type, addr, size) \
  42         ({ (void)(type); __access_ok((unsigned long)(addr), size); })
  43
  44 /*
  45  * The exception table consists of pairs of addresses: the first is the
  46  * address of an instruction that is allowed to fault, and the second is
  47  * the address at which the program should continue.  No registers are
  48  * modified, so it is entirely up to the continuation code to figure out
  49  * what to do.
  50  *
  51  * All the routines below use bits of fixup code that are out of line
  52  * with the main instruction path.  This means when everything is well,
  53  * we don't even have to jump over them.  Further, they do not intrude
  54  * on our cache or tlb entries.
  55  *
  56  * There is a special way how to put a range of potentially faulting
  57  * insns (like twenty ldd/std's with now intervening other instructions)
  58  * You specify address of first in insn and 0 in fixup and in the next
  59  * exception_table_entry you specify last potentially faulting insn + 1
  60  * and in fixup the routine which should handle the fault.
  61  * That fixup code will get
  62  * (faulting_insn_address - first_insn_in_the_range_address)/4
  63  * in %g2 (ie. index of the faulting instruction in the range).
  64  */
  65
  66 struct exception_table_entry
  67 {
  68         unsigned long insn, fixup;
  69 };
  70
  71 /* Returns 0 if exception not found and fixup otherwise.  */
  72 unsigned long search_extables_range(unsigned long addr, unsigned long *g2);
  73
  74 /* Uh, these should become the main single-value transfer routines..
  75  * They automatically use the right size if we just have the right
  76  * pointer type..
  77  *
  78  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  79  * and yet we don't want to do any pointers, because that is too much
  80  * of a performance impact. Thus we have a few rather ugly macros here,
  81  * and hide all the ugliness from the user.
  82  */
  83 #define put_user(x, ptr) ({ \
  84         unsigned long __pu_addr = (unsigned long)(ptr); \
  85         __chk_user_ptr(ptr); \
  86         __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \
  87 })
  88
  89 #define get_user(x, ptr) ({ \
  90         unsigned long __gu_addr = (unsigned long)(ptr); \
  91         __chk_user_ptr(ptr); \
  92         __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \
  93 })
  94
  95 /*
  96  * The "__xxx" versions do not do address space checking, useful when
  97  * doing multiple accesses to the same area (the user has to do the
  98  * checks by hand with "access_ok()")
  99  */
 100 #define __put_user(x, ptr) \
 101         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 102 #define __get_user(x, ptr) \
 103     __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr)))
 104
 105 struct __large_struct { unsigned long buf[100]; };
 106 #define __m(x) ((struct __large_struct __user *)(x))
 107
 108 #define __put_user_check(x, addr, size) ({ \
 109         register int __pu_ret; \
 110         if (__access_ok(addr, size)) { \
 111                 switch (size) { \
 112                 case 1: \
 113                         __put_user_asm(x, b, addr, __pu_ret); \
 114                         break; \
 115                 case 2: \
 116                         __put_user_asm(x, h, addr, __pu_ret); \
 117                         break; \
 118                 case 4: \
 119                         __put_user_asm(x, , addr, __pu_ret); \
 120                         break; \
 121                 case 8: \
 122                         __put_user_asm(x, d, addr, __pu_ret); \
 123                         break; \
 124                 default: \
 125                         __pu_ret = __put_user_bad(); \
 126                         break; \
 127                 } \
 128         } else { \
 129                 __pu_ret = -EFAULT; \
 130         } \
 131         __pu_ret; \
 132 })
 133
 134 #define __put_user_nocheck(x, addr, size) ({                    \
 135         register int __pu_ret;                                  \
 136         switch (size) {                                         \
 137         case 1: __put_user_asm(x, b, addr, __pu_ret); break;    \
 138         case 2: __put_user_asm(x, h, addr, __pu_ret); break;    \
 139         case 4: __put_user_asm(x, , addr, __pu_ret); break;     \
 140         case 8: __put_user_asm(x, d, addr, __pu_ret); break;    \
 141         default: __pu_ret = __put_user_bad(); break;            \
 142         } \
 143         __pu_ret; \
 144 })
 145
 146 #define __put_user_asm(x, size, addr, ret)                              \
 147 __asm__ __volatile__(                                                   \
 148                 "/* Put user asm, inline. */\n"                         \
 149         "1:\t"  "st"#size " %1, %2\n\t"                                 \
 150                 "clr    %0\n"                                           \
 151         "2:\n\n\t"                                                      \
 152                 ".section .fixup,#alloc,#execinstr\n\t"                 \
 153                 ".align 4\n"                                            \
 154         "3:\n\t"                                                        \
 155                 "b      2b\n\t"                                         \
 156                 " mov   %3, %0\n\t"                                     \
 157                 ".previous\n\n\t"                                       \
 158                 ".section __ex_table,#alloc\n\t"                        \
 159                 ".align 4\n\t"                                          \
 160                 ".word  1b, 3b\n\t"                                     \
 161                 ".previous\n\n\t"                                       \
 162                : "=&r" (ret) : "r" (x), "m" (*__m(addr)),               \
 163                  "i" (-EFAULT))
 164
 165 int __put_user_bad(void);
 166
 167 #define __get_user_check(x, addr, size, type) ({ \
 168         register int __gu_ret; \
 169         register unsigned long __gu_val; \
 170         if (__access_ok(addr, size)) { \
 171                 switch (size) { \
 172                 case 1: \
 173                          __get_user_asm(__gu_val, ub, addr, __gu_ret); \
 174                         break; \
 175                 case 2: \
 176                         __get_user_asm(__gu_val, uh, addr, __gu_ret); \
 177                         break; \
 178                 case 4: \
 179                         __get_user_asm(__gu_val, , addr, __gu_ret); \
 180                         break; \
 181                 case 8: \
 182                         __get_user_asm(__gu_val, d, addr, __gu_ret); \
 183                         break; \
 184                 default: \
 185                         __gu_val = 0; \
 186                         __gu_ret = __get_user_bad(); \
 187                         break; \
 188                 } \
 189          } else { \
 190                  __gu_val = 0; \
 191                  __gu_ret = -EFAULT; \
 192         } \
 193         x = (__force type) __gu_val; \
 194         __gu_ret; \
 195 })
 196
 197 #define __get_user_nocheck(x, addr, size, type) ({                      \
 198         register int __gu_ret;                                          \
 199         register unsigned long __gu_val;                                \
 200         switch (size) {                                                 \
 201         case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break;    \
 202         case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break;    \
 203         case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break;      \
 204         case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break;     \
 205         default:                                                        \
 206                 __gu_val = 0;                                           \
 207                 __gu_ret = __get_user_bad();                            \
 208                 break;                                                  \
 209         }                                                               \
 210         x = (__force type) __gu_val;                                    \
 211         __gu_ret;                                                       \
 212 })
 213
 214 #define __get_user_asm(x, size, addr, ret)                              \
 215 __asm__ __volatile__(                                                   \
 216                 "/* Get user asm, inline. */\n"                         \
 217         "1:\t"  "ld"#size " %2, %1\n\t"                                 \
 218                 "clr    %0\n"                                           \
 219         "2:\n\n\t"                                                      \
 220                 ".section .fixup,#alloc,#execinstr\n\t"                 \
 221                 ".align 4\n"                                            \
 222         "3:\n\t"                                                        \
 223                 "clr    %1\n\t"                                         \
 224                 "b      2b\n\t"                                         \
 225                 " mov   %3, %0\n\n\t"                                   \
 226                 ".previous\n\t"                                         \
 227                 ".section __ex_table,#alloc\n\t"                        \
 228                 ".align 4\n\t"                                          \
 229                 ".word  1b, 3b\n\n\t"                                   \
 230                 ".previous\n\t"                                         \
 231                : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)),             \
 232                  "i" (-EFAULT))
 233
 234 int __get_user_bad(void);
 235
 236 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size);
 237
 238 static inline unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 239 {
 240         return __copy_user(to, (__force void __user *) from, n);
 241 }
 242
 243 static inline unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 244 {
 245         return __copy_user((__force void __user *) to, from, n);
 246 }
 247
 248 #define INLINE_COPY_FROM_USER
 249 #define INLINE_COPY_TO_USER
 250
 251 static inline unsigned long __clear_user(void __user *addr, unsigned long size)
 252 {
 253         unsigned long ret;
 254
 255         __asm__ __volatile__ (
 256                 ".section __ex_table,#alloc\n\t"
 257                 ".align 4\n\t"
 258                 ".word 1f,3\n\t"
 259                 ".previous\n\t"
 260                 "mov %2, %%o1\n"
 261                 "1:\n\t"
 262                 "call __bzero\n\t"
 263                 " mov %1, %%o0\n\t"
 264                 "mov %%o0, %0\n"
 265                 : "=r" (ret) : "r" (addr), "r" (size) :
 266                 "o0", "o1", "o2", "o3", "o4", "o5", "o7",
 267                 "g1", "g2", "g3", "g4", "g5", "g7", "cc");
 268
 269         return ret;
 270 }
 271
 272 static inline unsigned long clear_user(void __user *addr, unsigned long n)
 273 {
 274         if (n && __access_ok((unsigned long) addr, n))
 275                 return __clear_user(addr, n);
 276         else
 277                 return n;
 278 }
 279
 280 __must_check long strnlen_user(const char __user *str, long n);
 281
 282 #endif /* _ASM_UACCESS_H */