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 #define get_user(x,ptr) ({ \ 100 unsigned long __gu_addr = (unsigned long)(ptr); \ 101 __chk_user_ptr(ptr); \ 102 __get_user_check((x),__gu_addr,sizeof(*(ptr)),__typeof__(*(ptr))); }) 103 104 /* 105 * The "__xxx" versions do not do address space checking, useful when 106 * doing multiple accesses to the same area (the user has to do the 107 * checks by hand with "access_ok()") 108 */ 109 #define __put_user(x,ptr) __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr))) 110 #define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)),__typeof__(*(ptr))) 111 112 struct __large_struct { unsigned long buf[100]; }; 113 #define __m(x) ((struct __large_struct __user *)(x)) 114 115 #define __put_user_check(x,addr,size) ({ \ 116 register int __pu_ret; \ 117 if (__access_ok(addr,size)) { \ 118 switch (size) { \ 119 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \ 120 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \ 121 case 4: __put_user_asm(x,,addr,__pu_ret); break; \ 122 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \ 123 default: __pu_ret = __put_user_bad(); break; \ 124 } } else { __pu_ret = -EFAULT; } __pu_ret; }) 125 126 #define __put_user_nocheck(x,addr,size) ({ \ 127 register int __pu_ret; \ 128 switch (size) { \ 129 case 1: __put_user_asm(x,b,addr,__pu_ret); break; \ 130 case 2: __put_user_asm(x,h,addr,__pu_ret); break; \ 131 case 4: __put_user_asm(x,,addr,__pu_ret); break; \ 132 case 8: __put_user_asm(x,d,addr,__pu_ret); break; \ 133 default: __pu_ret = __put_user_bad(); break; \ 134 } __pu_ret; }) 135 136 #define __put_user_asm(x,size,addr,ret) \ 137 __asm__ __volatile__( \ 138 "/* Put user asm, inline. */\n" \ 139 "1:\t" "st"#size " %1, %2\n\t" \ 140 "clr %0\n" \ 141 "2:\n\n\t" \ 142 ".section .fixup,#alloc,#execinstr\n\t" \ 143 ".align 4\n" \ 144 "3:\n\t" \ 145 "b 2b\n\t" \ 146 " mov %3, %0\n\t" \ 147 ".previous\n\n\t" \ 148 ".section __ex_table,#alloc\n\t" \ 149 ".align 4\n\t" \ 150 ".word 1b, 3b\n\t" \ 151 ".previous\n\n\t" \ 152 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \ 153 "i" (-EFAULT)) 154 155 int __put_user_bad(void); 156 157 #define __get_user_check(x,addr,size,type) ({ \ 158 register int __gu_ret; \ 159 register unsigned long __gu_val; \ 160 if (__access_ok(addr,size)) { \ 161 switch (size) { \ 162 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \ 163 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \ 164 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \ 165 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \ 166 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \ 167 } } else { __gu_val = 0; __gu_ret = -EFAULT; } x = (type) __gu_val; __gu_ret; }) 168 169 #define __get_user_check_ret(x,addr,size,type,retval) ({ \ 170 register unsigned long __gu_val __asm__ ("l1"); \ 171 if (__access_ok(addr,size)) { \ 172 switch (size) { \ 173 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \ 174 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \ 175 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \ 176 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \ 177 default: if (__get_user_bad()) return retval; \ 178 } x = (type) __gu_val; } else return retval; }) 179 180 #define __get_user_nocheck(x,addr,size,type) ({ \ 181 register int __gu_ret; \ 182 register unsigned long __gu_val; \ 183 switch (size) { \ 184 case 1: __get_user_asm(__gu_val,ub,addr,__gu_ret); break; \ 185 case 2: __get_user_asm(__gu_val,uh,addr,__gu_ret); break; \ 186 case 4: __get_user_asm(__gu_val,,addr,__gu_ret); break; \ 187 case 8: __get_user_asm(__gu_val,d,addr,__gu_ret); break; \ 188 default: __gu_val = 0; __gu_ret = __get_user_bad(); break; \ 189 } x = (type) __gu_val; __gu_ret; }) 190 191 #define __get_user_nocheck_ret(x,addr,size,type,retval) ({ \ 192 register unsigned long __gu_val __asm__ ("l1"); \ 193 switch (size) { \ 194 case 1: __get_user_asm_ret(__gu_val,ub,addr,retval); break; \ 195 case 2: __get_user_asm_ret(__gu_val,uh,addr,retval); break; \ 196 case 4: __get_user_asm_ret(__gu_val,,addr,retval); break; \ 197 case 8: __get_user_asm_ret(__gu_val,d,addr,retval); break; \ 198 default: if (__get_user_bad()) return retval; \ 199 } x = (type) __gu_val; }) 200 201 #define __get_user_asm(x,size,addr,ret) \ 202 __asm__ __volatile__( \ 203 "/* Get user asm, inline. */\n" \ 204 "1:\t" "ld"#size " %2, %1\n\t" \ 205 "clr %0\n" \ 206 "2:\n\n\t" \ 207 ".section .fixup,#alloc,#execinstr\n\t" \ 208 ".align 4\n" \ 209 "3:\n\t" \ 210 "clr %1\n\t" \ 211 "b 2b\n\t" \ 212 " mov %3, %0\n\n\t" \ 213 ".previous\n\t" \ 214 ".section __ex_table,#alloc\n\t" \ 215 ".align 4\n\t" \ 216 ".word 1b, 3b\n\n\t" \ 217 ".previous\n\t" \ 218 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \ 219 "i" (-EFAULT)) 220 221 #define __get_user_asm_ret(x,size,addr,retval) \ 222 if (__builtin_constant_p(retval) && retval == -EFAULT) \ 223 __asm__ __volatile__( \ 224 "/* Get user asm ret, inline. */\n" \ 225 "1:\t" "ld"#size " %1, %0\n\n\t" \ 226 ".section __ex_table,#alloc\n\t" \ 227 ".align 4\n\t" \ 228 ".word 1b,__ret_efault\n\n\t" \ 229 ".previous\n\t" \ 230 : "=&r" (x) : "m" (*__m(addr))); \ 231 else \ 232 __asm__ __volatile__( \ 233 "/* Get user asm ret, inline. */\n" \ 234 "1:\t" "ld"#size " %1, %0\n\n\t" \ 235 ".section .fixup,#alloc,#execinstr\n\t" \ 236 ".align 4\n" \ 237 "3:\n\t" \ 238 "ret\n\t" \ 239 " restore %%g0, %2, %%o0\n\n\t" \ 240 ".previous\n\t" \ 241 ".section __ex_table,#alloc\n\t" \ 242 ".align 4\n\t" \ 243 ".word 1b, 3b\n\n\t" \ 244 ".previous\n\t" \ 245 : "=&r" (x) : "m" (*__m(addr)), "i" (retval)) 246 247 int __get_user_bad(void); 248 249 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size); 250 251 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n) 252 { 253 if (n && __access_ok((unsigned long) to, n)) 254 return __copy_user(to, (__force void __user *) from, n); 255 else 256 return n; 257 } 258 259 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n) 260 { 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 return __copy_user((__force void __user *) to, from, n); 268 else 269 return n; 270 } 271 272 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n) 273 { 274 return __copy_user((__force void __user *) to, from, n); 275 } 276 277 #define __copy_to_user_inatomic __copy_to_user 278 #define __copy_from_user_inatomic __copy_from_user 279 280 static inline unsigned long __clear_user(void __user *addr, unsigned long size) 281 { 282 unsigned long ret; 283 284 __asm__ __volatile__ ( 285 ".section __ex_table,#alloc\n\t" 286 ".align 4\n\t" 287 ".word 1f,3\n\t" 288 ".previous\n\t" 289 "mov %2, %%o1\n" 290 "1:\n\t" 291 "call __bzero\n\t" 292 " mov %1, %%o0\n\t" 293 "mov %%o0, %0\n" 294 : "=r" (ret) : "r" (addr), "r" (size) : 295 "o0", "o1", "o2", "o3", "o4", "o5", "o7", 296 "g1", "g2", "g3", "g4", "g5", "g7", "cc"); 297 298 return ret; 299 } 300 301 static inline unsigned long clear_user(void __user *addr, unsigned long n) 302 { 303 if (n && __access_ok((unsigned long) addr, n)) 304 return __clear_user(addr, n); 305 else 306 return n; 307 } 308 309 __must_check long strlen_user(const char __user *str); 310 __must_check long strnlen_user(const char __user *str, long n); 311 312 #endif /* __ASSEMBLY__ */ 313 314 #endif /* _ASM_UACCESS_H */ 315