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/string.h> 13 #endif 14 15 #ifndef __ASSEMBLY__ 16 17 #include <asm/processor.h> 18 19 #define ARCH_HAS_SORT_EXTABLE 20 #define ARCH_HAS_SEARCH_EXTABLE 21 22 /* Sparc is not segmented, however we need to be able to fool access_ok() 23 * when doing system calls from kernel mode legitimately. 24 * 25 * "For historical reasons, these macros are grossly misnamed." -Linus 26 */ 27 28 #define KERNEL_DS ((mm_segment_t) { 0 }) 29 #define USER_DS ((mm_segment_t) { -1 }) 30 31 #define get_ds() (KERNEL_DS) 32 #define get_fs() (current->thread.current_ds) 33 #define set_fs(val) ((current->thread.current_ds) = (val)) 34 35 #define segment_eq(a, b) ((a).seg == (b).seg) 36 37 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test 38 * can be fairly lightweight. 39 * No one can read/write anything from userland in the kernel space by setting 40 * large size and address near to PAGE_OFFSET - a fault will break his intentions. 41 */ 42 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; }) 43 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS)) 44 #define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size))) 45 #define access_ok(type, addr, size) \ 46 ({ (void)(type); __access_ok((unsigned long)(addr), size); }) 47 48 /* 49 * The exception table consists of pairs of addresses: the first is the 50 * address of an instruction that is allowed to fault, and the second is 51 * the address at which the program should continue. No registers are 52 * modified, so it is entirely up to the continuation code to figure out 53 * what to do. 54 * 55 * All the routines below use bits of fixup code that are out of line 56 * with the main instruction path. This means when everything is well, 57 * we don't even have to jump over them. Further, they do not intrude 58 * on our cache or tlb entries. 59 * 60 * There is a special way how to put a range of potentially faulting 61 * insns (like twenty ldd/std's with now intervening other instructions) 62 * You specify address of first in insn and 0 in fixup and in the next 63 * exception_table_entry you specify last potentially faulting insn + 1 64 * and in fixup the routine which should handle the fault. 65 * That fixup code will get 66 * (faulting_insn_address - first_insn_in_the_range_address)/4 67 * in %g2 (ie. index of the faulting instruction in the range). 68 */ 69 70 struct exception_table_entry 71 { 72 unsigned long insn, fixup; 73 }; 74 75 /* Returns 0 if exception not found and fixup otherwise. */ 76 unsigned long search_extables_range(unsigned long addr, unsigned long *g2); 77 78 void __ret_efault(void); 79 80 /* Uh, these should become the main single-value transfer routines.. 81 * They automatically use the right size if we just have the right 82 * pointer type.. 83 * 84 * This gets kind of ugly. We want to return _two_ values in "get_user()" 85 * and yet we don't want to do any pointers, because that is too much 86 * of a performance impact. Thus we have a few rather ugly macros here, 87 * and hide all the ugliness from the user. 88 */ 89 #define put_user(x, ptr) ({ \ 90 unsigned long __pu_addr = (unsigned long)(ptr); \ 91 __chk_user_ptr(ptr); \ 92 __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \ 93 }) 94 95 #define get_user(x, ptr) ({ \ 96 unsigned long __gu_addr = (unsigned long)(ptr); \ 97 __chk_user_ptr(ptr); \ 98 __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \ 99 }) 100 101 /* 102 * The "__xxx" versions do not do address space checking, useful when 103 * doing multiple accesses to the same area (the user has to do the 104 * checks by hand with "access_ok()") 105 */ 106 #define __put_user(x, ptr) \ 107 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 108 #define __get_user(x, ptr) \ 109 __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr))) 110 111 struct __large_struct { unsigned long buf[100]; }; 112 #define __m(x) ((struct __large_struct __user *)(x)) 113 114 #define __put_user_check(x, addr, size) ({ \ 115 register int __pu_ret; \ 116 if (__access_ok(addr, size)) { \ 117 switch (size) { \ 118 case 1: \ 119 __put_user_asm(x, b, addr, __pu_ret); \ 120 break; \ 121 case 2: \ 122 __put_user_asm(x, h, addr, __pu_ret); \ 123 break; \ 124 case 4: \ 125 __put_user_asm(x, , addr, __pu_ret); \ 126 break; \ 127 case 8: \ 128 __put_user_asm(x, d, addr, __pu_ret); \ 129 break; \ 130 default: \ 131 __pu_ret = __put_user_bad(); \ 132 break; \ 133 } \ 134 } else { \ 135 __pu_ret = -EFAULT; \ 136 } \ 137 __pu_ret; \ 138 }) 139 140 #define __put_user_nocheck(x, addr, size) ({ \ 141 register int __pu_ret; \ 142 switch (size) { \ 143 case 1: __put_user_asm(x, b, addr, __pu_ret); break; \ 144 case 2: __put_user_asm(x, h, addr, __pu_ret); break; \ 145 case 4: __put_user_asm(x, , addr, __pu_ret); break; \ 146 case 8: __put_user_asm(x, d, addr, __pu_ret); break; \ 147 default: __pu_ret = __put_user_bad(); break; \ 148 } \ 149 __pu_ret; \ 150 }) 151 152 #define __put_user_asm(x, size, addr, ret) \ 153 __asm__ __volatile__( \ 154 "/* Put user asm, inline. */\n" \ 155 "1:\t" "st"#size " %1, %2\n\t" \ 156 "clr %0\n" \ 157 "2:\n\n\t" \ 158 ".section .fixup,#alloc,#execinstr\n\t" \ 159 ".align 4\n" \ 160 "3:\n\t" \ 161 "b 2b\n\t" \ 162 " mov %3, %0\n\t" \ 163 ".previous\n\n\t" \ 164 ".section __ex_table,#alloc\n\t" \ 165 ".align 4\n\t" \ 166 ".word 1b, 3b\n\t" \ 167 ".previous\n\n\t" \ 168 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \ 169 "i" (-EFAULT)) 170 171 int __put_user_bad(void); 172 173 #define __get_user_check(x, addr, size, type) ({ \ 174 register int __gu_ret; \ 175 register unsigned long __gu_val; \ 176 if (__access_ok(addr, size)) { \ 177 switch (size) { \ 178 case 1: \ 179 __get_user_asm(__gu_val, ub, addr, __gu_ret); \ 180 break; \ 181 case 2: \ 182 __get_user_asm(__gu_val, uh, addr, __gu_ret); \ 183 break; \ 184 case 4: \ 185 __get_user_asm(__gu_val, , addr, __gu_ret); \ 186 break; \ 187 case 8: \ 188 __get_user_asm(__gu_val, d, addr, __gu_ret); \ 189 break; \ 190 default: \ 191 __gu_val = 0; \ 192 __gu_ret = __get_user_bad(); \ 193 break; \ 194 } \ 195 } else { \ 196 __gu_val = 0; \ 197 __gu_ret = -EFAULT; \ 198 } \ 199 x = (__force type) __gu_val; \ 200 __gu_ret; \ 201 }) 202 203 #define __get_user_nocheck(x, addr, size, type) ({ \ 204 register int __gu_ret; \ 205 register unsigned long __gu_val; \ 206 switch (size) { \ 207 case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break; \ 208 case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break; \ 209 case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break; \ 210 case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break; \ 211 default: \ 212 __gu_val = 0; \ 213 __gu_ret = __get_user_bad(); \ 214 break; \ 215 } \ 216 x = (__force type) __gu_val; \ 217 __gu_ret; \ 218 }) 219 220 #define __get_user_asm(x, size, addr, ret) \ 221 __asm__ __volatile__( \ 222 "/* Get user asm, inline. */\n" \ 223 "1:\t" "ld"#size " %2, %1\n\t" \ 224 "clr %0\n" \ 225 "2:\n\n\t" \ 226 ".section .fixup,#alloc,#execinstr\n\t" \ 227 ".align 4\n" \ 228 "3:\n\t" \ 229 "clr %1\n\t" \ 230 "b 2b\n\t" \ 231 " mov %3, %0\n\n\t" \ 232 ".previous\n\t" \ 233 ".section __ex_table,#alloc\n\t" \ 234 ".align 4\n\t" \ 235 ".word 1b, 3b\n\n\t" \ 236 ".previous\n\t" \ 237 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \ 238 "i" (-EFAULT)) 239 240 int __get_user_bad(void); 241 242 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size); 243 244 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n) 245 { 246 if (n && __access_ok((unsigned long) to, n)) { 247 check_object_size(from, n, true); 248 return __copy_user(to, (__force void __user *) from, n); 249 } else 250 return n; 251 } 252 253 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n) 254 { 255 check_object_size(from, n, true); 256 return __copy_user(to, (__force void __user *) from, n); 257 } 258 259 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n) 260 { 261 if (n && __access_ok((unsigned long) from, n)) { 262 check_object_size(to, n, false); 263 return __copy_user((__force void __user *) to, from, n); 264 } else { 265 memset(to, 0, n); 266 return n; 267 } 268 } 269 270 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n) 271 { 272 return __copy_user((__force void __user *) to, from, n); 273 } 274 275 #define __copy_to_user_inatomic __copy_to_user 276 #define __copy_from_user_inatomic __copy_from_user 277 278 static inline unsigned long __clear_user(void __user *addr, unsigned long size) 279 { 280 unsigned long ret; 281 282 __asm__ __volatile__ ( 283 ".section __ex_table,#alloc\n\t" 284 ".align 4\n\t" 285 ".word 1f,3\n\t" 286 ".previous\n\t" 287 "mov %2, %%o1\n" 288 "1:\n\t" 289 "call __bzero\n\t" 290 " mov %1, %%o0\n\t" 291 "mov %%o0, %0\n" 292 : "=r" (ret) : "r" (addr), "r" (size) : 293 "o0", "o1", "o2", "o3", "o4", "o5", "o7", 294 "g1", "g2", "g3", "g4", "g5", "g7", "cc"); 295 296 return ret; 297 } 298 299 static inline unsigned long clear_user(void __user *addr, unsigned long n) 300 { 301 if (n && __access_ok((unsigned long) addr, n)) 302 return __clear_user(addr, n); 303 else 304 return n; 305 } 306 307 __must_check long strlen_user(const char __user *str); 308 __must_check long strnlen_user(const char __user *str, long n); 309 310 #endif /* __ASSEMBLY__ */ 311 312 #endif /* _ASM_UACCESS_H */ 313