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   1 /* $Id: uaccess.h,v 1.35 2002/02/09 19:49:31 davem Exp $ */
   2 #ifndef _ASM_UACCESS_H
   3 #define _ASM_UACCESS_H
   4
   5 /*
   6  * User space memory access functions
   7  */
   8
   9 #ifdef __KERNEL__
  10 #include <linux/compiler.h>
  11 #include <linux/sched.h>
  12 #include <linux/string.h>
  13 #include <asm/a.out.h>
  14 #include <asm/asi.h>
  15 #include <asm/system.h>
  16 #include <asm/spitfire.h>
  17 #include <asm-generic/uaccess.h>
  18 #endif
  19
  20 #ifndef __ASSEMBLY__
  21
  22 /*
  23  * Sparc64 is segmented, though more like the M68K than the I386.
  24  * We use the secondary ASI to address user memory, which references a
  25  * completely different VM map, thus there is zero chance of the user
  26  * doing something queer and tricking us into poking kernel memory.
  27  *
  28  * What is left here is basically what is needed for the other parts of
  29  * the kernel that expect to be able to manipulate, erum, "segments".
  30  * Or perhaps more properly, permissions.
  31  *
  32  * "For historical reasons, these macros are grossly misnamed." -Linus
  33  */
  34
  35 #define KERNEL_DS   ((mm_segment_t) { ASI_P })
  36 #define USER_DS     ((mm_segment_t) { ASI_AIUS })       /* har har har */
  37
  38 #define VERIFY_READ     0
  39 #define VERIFY_WRITE    1
  40
  41 #define get_fs() ((mm_segment_t) { get_thread_current_ds() })
  42 #define get_ds() (KERNEL_DS)
  43
  44 #define segment_eq(a,b)  ((a).seg == (b).seg)
  45
  46 #define set_fs(val)                                                             \
  47 do {                                                                            \
  48         set_thread_current_ds((val).seg);                                       \
  49         __asm__ __volatile__ ("wr %%g0, %0, %%asi" : : "r" ((val).seg));        \
  50 } while(0)
  51
  52 static inline int __access_ok(const void __user * addr, unsigned long size)
  53 {
  54         return 1;
  55 }
  56
  57 static inline int access_ok(int type, const void __user * addr, unsigned long size)
  58 {
  59         return 1;
  60 }
  61
  62 /*
  63  * The exception table consists of pairs of addresses: the first is the
  64  * address of an instruction that is allowed to fault, and the second is
  65  * the address at which the program should continue.  No registers are
  66  * modified, so it is entirely up to the continuation code to figure out
  67  * what to do.
  68  *
  69  * All the routines below use bits of fixup code that are out of line
  70  * with the main instruction path.  This means when everything is well,
  71  * we don't even have to jump over them.  Further, they do not intrude
  72  * on our cache or tlb entries.
  73  */
  74
  75 struct exception_table_entry {
  76         unsigned int insn, fixup;
  77 };
  78
  79 extern void __ret_efault(void);
  80 extern void __retl_efault(void);
  81
  82 /* Uh, these should become the main single-value transfer routines..
  83  * They automatically use the right size if we just have the right
  84  * pointer type..
  85  *
  86  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  87  * and yet we don't want to do any pointers, because that is too much
  88  * of a performance impact. Thus we have a few rather ugly macros here,
  89  * and hide all the ugliness from the user.
  90  */
  91 #define put_user(x,ptr) ({ \
  92 unsigned long __pu_addr = (unsigned long)(ptr); \
  93 __chk_user_ptr(ptr); \
  94 __put_user_nocheck((__typeof__(*(ptr)))(x),__pu_addr,sizeof(*(ptr))); })
  95
  96 #define get_user(x,ptr) ({ \
  97 unsigned long __gu_addr = (unsigned long)(ptr); \
  98 __chk_user_ptr(ptr); \
  99 __get_user_nocheck((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); })
 100
 101 #define __put_user(x,ptr) put_user(x,ptr)
 102 #define __get_user(x,ptr) get_user(x,ptr)
 103
 104 struct __large_struct { unsigned long buf[100]; };
 105 #define __m(x) ((struct __large_struct *)(x))
 106
 107 #define __put_user_nocheck(data,addr,size) ({ \
 108 register int __pu_ret; \
 109 switch (size) { \
 110 case 1: __put_user_asm(data,b,addr,__pu_ret); break; \
 111 case 2: __put_user_asm(data,h,addr,__pu_ret); break; \
 112 case 4: __put_user_asm(data,w,addr,__pu_ret); break; \
 113 case 8: __put_user_asm(data,x,addr,__pu_ret); break; \
 114 default: __pu_ret = __put_user_bad(); break; \
 115 } __pu_ret; })
 116
 117 #define __put_user_asm(x,size,addr,ret)                                 \
 118 __asm__ __volatile__(                                                   \
 119         "/* Put user asm, inline. */\n"                                 \
 120 "1:\t"  "st"#size "a %1, [%2] %%asi\n\t"                                \
 121         "clr    %0\n"                                                   \
 122 "2:\n\n\t"                                                              \
 123         ".section .fixup,#alloc,#execinstr\n\t"                         \
 124         ".align 4\n"                                                    \
 125 "3:\n\t"                                                                \
 126         "b      2b\n\t"                                                 \
 127         " mov   %3, %0\n\n\t"                                           \
 128         ".previous\n\t"                                                 \
 129         ".section __ex_table,\"a\"\n\t"                                 \
 130         ".align 4\n\t"                                                  \
 131         ".word  1b, 3b\n\t"                                             \
 132         ".previous\n\n\t"                                               \
 133        : "=r" (ret) : "r" (x), "r" (__m(addr)),                         \
 134          "i" (-EFAULT))
 135
 136 extern int __put_user_bad(void);
 137
 138 #define __get_user_nocheck(data,addr,size,type) ({ \
 139 register int __gu_ret; \
 140 register unsigned long __gu_val; \
 141 switch (size) { \
 142 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \
 143 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \
 144 case 4: __get_user_asm(__gu_val,uw,addr,__gu_ret); break; \
 145 case 8: __get_user_asm(__gu_val,x,addr,__gu_ret); break; \
 146 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \
 147 } data = (type) __gu_val; __gu_ret; })
 148
 149 #define __get_user_nocheck_ret(data,addr,size,type,retval) ({ \
 150 register unsigned long __gu_val __asm__ ("l1"); \
 151 switch (size) { \
 152 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \
 153 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \
 154 case 4: __get_user_asm_ret(__gu_val,uw,addr,retval); break; \
 155 case 8: __get_user_asm_ret(__gu_val,x,addr,retval); break; \
 156 default: if (__get_user_bad()) return retval; \
 157 } data = (type) __gu_val; })
 158
 159 #define __get_user_asm(x,size,addr,ret)                                 \
 160 __asm__ __volatile__(                                                   \
 161         "/* Get user asm, inline. */\n"                                 \
 162 "1:\t"  "ld"#size "a [%2] %%asi, %1\n\t"                                \
 163         "clr    %0\n"                                                   \
 164 "2:\n\n\t"                                                              \
 165         ".section .fixup,#alloc,#execinstr\n\t"                         \
 166         ".align 4\n"                                                    \
 167 "3:\n\t"                                                                \
 168         "clr    %1\n\t"                                                 \
 169         "b      2b\n\t"                                                 \
 170         " mov   %3, %0\n\n\t"                                           \
 171         ".previous\n\t"                                                 \
 172         ".section __ex_table,\"a\"\n\t"                                 \
 173         ".align 4\n\t"                                                  \
 174         ".word  1b, 3b\n\n\t"                                           \
 175         ".previous\n\t"                                                 \
 176        : "=r" (ret), "=r" (x) : "r" (__m(addr)),                        \
 177          "i" (-EFAULT))
 178
 179 #define __get_user_asm_ret(x,size,addr,retval)                          \
 180 if (__builtin_constant_p(retval) && retval == -EFAULT)                  \
 181 __asm__ __volatile__(                                                   \
 182         "/* Get user asm ret, inline. */\n"                             \
 183 "1:\t"  "ld"#size "a [%1] %%asi, %0\n\n\t"                              \
 184         ".section __ex_table,\"a\"\n\t"                                 \
 185         ".align 4\n\t"                                                  \
 186         ".word  1b,__ret_efault\n\n\t"                                  \
 187         ".previous\n\t"                                                 \
 188        : "=r" (x) : "r" (__m(addr)));                                   \
 189 else                                                                    \
 190 __asm__ __volatile__(                                                   \
 191         "/* Get user asm ret, inline. */\n"                             \
 192 "1:\t"  "ld"#size "a [%1] %%asi, %0\n\n\t"                              \
 193         ".section .fixup,#alloc,#execinstr\n\t"                         \
 194         ".align 4\n"                                                    \
 195 "3:\n\t"                                                                \
 196         "ret\n\t"                                                       \
 197         " restore %%g0, %2, %%o0\n\n\t"                                 \
 198         ".previous\n\t"                                                 \
 199         ".section __ex_table,\"a\"\n\t"                                 \
 200         ".align 4\n\t"                                                  \
 201         ".word  1b, 3b\n\n\t"                                           \
 202         ".previous\n\t"                                                 \
 203        : "=r" (x) : "r" (__m(addr)), "i" (retval))
 204
 205 extern int __get_user_bad(void);
 206
 207 extern unsigned long __must_check ___copy_from_user(void *to,
 208                                                     const void __user *from,
 209                                                     unsigned long size);
 210 extern unsigned long copy_from_user_fixup(void *to, const void __user *from,
 211                                           unsigned long size);
 212 static inline unsigned long __must_check
 213 copy_from_user(void *to, const void __user *from, unsigned long size)
 214 {
 215         unsigned long ret = ___copy_from_user(to, from, size);
 216
 217         if (unlikely(ret))
 218                 ret = copy_from_user_fixup(to, from, size);
 219         return ret;
 220 }
 221 #define __copy_from_user copy_from_user
 222
 223 extern unsigned long __must_check ___copy_to_user(void __user *to,
 224                                                   const void *from,
 225                                                   unsigned long size);
 226 extern unsigned long copy_to_user_fixup(void __user *to, const void *from,
 227                                         unsigned long size);
 228 static inline unsigned long __must_check
 229 copy_to_user(void __user *to, const void *from, unsigned long size)
 230 {
 231         unsigned long ret = ___copy_to_user(to, from, size);
 232
 233         if (unlikely(ret))
 234                 ret = copy_to_user_fixup(to, from, size);
 235         return ret;
 236 }
 237 #define __copy_to_user copy_to_user
 238
 239 extern unsigned long __must_check ___copy_in_user(void __user *to,
 240                                                   const void __user *from,
 241                                                   unsigned long size);
 242 extern unsigned long copy_in_user_fixup(void __user *to, void __user *from,
 243                                         unsigned long size);
 244 static inline unsigned long __must_check
 245 copy_in_user(void __user *to, void __user *from, unsigned long size)
 246 {
 247         unsigned long ret = ___copy_in_user(to, from, size);
 248
 249         if (unlikely(ret))
 250                 ret = copy_in_user_fixup(to, from, size);
 251         return ret;
 252 }
 253 #define __copy_in_user copy_in_user
 254
 255 extern unsigned long __must_check __clear_user(void __user *, unsigned long);
 256
 257 #define clear_user __clear_user
 258
 259 extern long __must_check __strncpy_from_user(char *dest, const char __user *src, long count);
 260
 261 #define strncpy_from_user __strncpy_from_user
 262
 263 extern long __strlen_user(const char __user *);
 264 extern long __strnlen_user(const char __user *, long len);
 265
 266 #define strlen_user __strlen_user
 267 #define strnlen_user __strnlen_user
 268 #define __copy_to_user_inatomic __copy_to_user
 269 #define __copy_from_user_inatomic __copy_from_user
 270
 271 #endif  /* __ASSEMBLY__ */
 272
 273 #endif /* _ASM_UACCESS_H */