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 (segment_eq(get_fs(), KERNEL_DS)) 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 void __ret_efault(void); 75 76 /* Uh, these should become the main single-value transfer routines.. 77 * They automatically use the right size if we just have the right 78 * pointer type.. 79 * 80 * This gets kind of ugly. We want to return _two_ values in "get_user()" 81 * and yet we don't want to do any pointers, because that is too much 82 * of a performance impact. Thus we have a few rather ugly macros here, 83 * and hide all the ugliness from the user. 84 */ 85 #define put_user(x, ptr) ({ \ 86 unsigned long __pu_addr = (unsigned long)(ptr); \ 87 __chk_user_ptr(ptr); \ 88 __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \ 89 }) 90 91 #define get_user(x, ptr) ({ \ 92 unsigned long __gu_addr = (unsigned long)(ptr); \ 93 __chk_user_ptr(ptr); \ 94 __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \ 95 }) 96 97 /* 98 * The "__xxx" versions do not do address space checking, useful when 99 * doing multiple accesses to the same area (the user has to do the 100 * checks by hand with "access_ok()") 101 */ 102 #define __put_user(x, ptr) \ 103 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 104 #define __get_user(x, ptr) \ 105 __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr))) 106 107 struct __large_struct { unsigned long buf[100]; }; 108 #define __m(x) ((struct __large_struct __user *)(x)) 109 110 #define __put_user_check(x, addr, size) ({ \ 111 register int __pu_ret; \ 112 if (__access_ok(addr, size)) { \ 113 switch (size) { \ 114 case 1: \ 115 __put_user_asm(x, b, addr, __pu_ret); \ 116 break; \ 117 case 2: \ 118 __put_user_asm(x, h, addr, __pu_ret); \ 119 break; \ 120 case 4: \ 121 __put_user_asm(x, , addr, __pu_ret); \ 122 break; \ 123 case 8: \ 124 __put_user_asm(x, d, addr, __pu_ret); \ 125 break; \ 126 default: \ 127 __pu_ret = __put_user_bad(); \ 128 break; \ 129 } \ 130 } else { \ 131 __pu_ret = -EFAULT; \ 132 } \ 133 __pu_ret; \ 134 }) 135 136 #define __put_user_nocheck(x, addr, size) ({ \ 137 register int __pu_ret; \ 138 switch (size) { \ 139 case 1: __put_user_asm(x, b, addr, __pu_ret); break; \ 140 case 2: __put_user_asm(x, h, addr, __pu_ret); break; \ 141 case 4: __put_user_asm(x, , addr, __pu_ret); break; \ 142 case 8: __put_user_asm(x, d, addr, __pu_ret); break; \ 143 default: __pu_ret = __put_user_bad(); break; \ 144 } \ 145 __pu_ret; \ 146 }) 147 148 #define __put_user_asm(x, size, addr, ret) \ 149 __asm__ __volatile__( \ 150 "/* Put user asm, inline. */\n" \ 151 "1:\t" "st"#size " %1, %2\n\t" \ 152 "clr %0\n" \ 153 "2:\n\n\t" \ 154 ".section .fixup,#alloc,#execinstr\n\t" \ 155 ".align 4\n" \ 156 "3:\n\t" \ 157 "b 2b\n\t" \ 158 " mov %3, %0\n\t" \ 159 ".previous\n\n\t" \ 160 ".section __ex_table,#alloc\n\t" \ 161 ".align 4\n\t" \ 162 ".word 1b, 3b\n\t" \ 163 ".previous\n\n\t" \ 164 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \ 165 "i" (-EFAULT)) 166 167 int __put_user_bad(void); 168 169 #define __get_user_check(x, addr, size, type) ({ \ 170 register int __gu_ret; \ 171 register unsigned long __gu_val; \ 172 if (__access_ok(addr, size)) { \ 173 switch (size) { \ 174 case 1: \ 175 __get_user_asm(__gu_val, ub, addr, __gu_ret); \ 176 break; \ 177 case 2: \ 178 __get_user_asm(__gu_val, uh, addr, __gu_ret); \ 179 break; \ 180 case 4: \ 181 __get_user_asm(__gu_val, , addr, __gu_ret); \ 182 break; \ 183 case 8: \ 184 __get_user_asm(__gu_val, d, addr, __gu_ret); \ 185 break; \ 186 default: \ 187 __gu_val = 0; \ 188 __gu_ret = __get_user_bad(); \ 189 break; \ 190 } \ 191 } else { \ 192 __gu_val = 0; \ 193 __gu_ret = -EFAULT; \ 194 } \ 195 x = (__force type) __gu_val; \ 196 __gu_ret; \ 197 }) 198 199 #define __get_user_nocheck(x, addr, size, type) ({ \ 200 register int __gu_ret; \ 201 register unsigned long __gu_val; \ 202 switch (size) { \ 203 case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break; \ 204 case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break; \ 205 case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break; \ 206 case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break; \ 207 default: \ 208 __gu_val = 0; \ 209 __gu_ret = __get_user_bad(); \ 210 break; \ 211 } \ 212 x = (__force type) __gu_val; \ 213 __gu_ret; \ 214 }) 215 216 #define __get_user_asm(x, size, addr, ret) \ 217 __asm__ __volatile__( \ 218 "/* Get user asm, inline. */\n" \ 219 "1:\t" "ld"#size " %2, %1\n\t" \ 220 "clr %0\n" \ 221 "2:\n\n\t" \ 222 ".section .fixup,#alloc,#execinstr\n\t" \ 223 ".align 4\n" \ 224 "3:\n\t" \ 225 "clr %1\n\t" \ 226 "b 2b\n\t" \ 227 " mov %3, %0\n\n\t" \ 228 ".previous\n\t" \ 229 ".section __ex_table,#alloc\n\t" \ 230 ".align 4\n\t" \ 231 ".word 1b, 3b\n\n\t" \ 232 ".previous\n\t" \ 233 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \ 234 "i" (-EFAULT)) 235 236 int __get_user_bad(void); 237 238 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size); 239 240 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n) 241 { 242 if (n && __access_ok((unsigned long) to, n)) { 243 check_object_size(from, n, true); 244 return __copy_user(to, (__force void __user *) from, n); 245 } else 246 return n; 247 } 248 249 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n) 250 { 251 check_object_size(from, n, true); 252 return __copy_user(to, (__force void __user *) from, n); 253 } 254 255 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n) 256 { 257 if (n && __access_ok((unsigned long) from, n)) { 258 check_object_size(to, n, false); 259 return __copy_user((__force void __user *) to, from, n); 260 } else { 261 memset(to, 0, n); 262 return n; 263 } 264 } 265 266 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n) 267 { 268 return __copy_user((__force void __user *) to, from, n); 269 } 270 271 #define __copy_to_user_inatomic __copy_to_user 272 #define __copy_from_user_inatomic __copy_from_user 273 274 static inline unsigned long __clear_user(void __user *addr, unsigned long size) 275 { 276 unsigned long ret; 277 278 __asm__ __volatile__ ( 279 ".section __ex_table,#alloc\n\t" 280 ".align 4\n\t" 281 ".word 1f,3\n\t" 282 ".previous\n\t" 283 "mov %2, %%o1\n" 284 "1:\n\t" 285 "call __bzero\n\t" 286 " mov %1, %%o0\n\t" 287 "mov %%o0, %0\n" 288 : "=r" (ret) : "r" (addr), "r" (size) : 289 "o0", "o1", "o2", "o3", "o4", "o5", "o7", 290 "g1", "g2", "g3", "g4", "g5", "g7", "cc"); 291 292 return ret; 293 } 294 295 static inline unsigned long clear_user(void __user *addr, unsigned long n) 296 { 297 if (n && __access_ok((unsigned long) addr, n)) 298 return __clear_user(addr, n); 299 else 300 return n; 301 } 302 303 __must_check long strlen_user(const char __user *str); 304 __must_check long strnlen_user(const char __user *str, long n); 305 306 #endif /* _ASM_UACCESS_H */ 307