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 }) 99 100 #define get_user(x, ptr) ({ \ 101 unsigned long __gu_addr = (unsigned long)(ptr); \ 102 __chk_user_ptr(ptr); \ 103 __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \ 104 }) 105 106 /* 107 * The "__xxx" versions do not do address space checking, useful when 108 * doing multiple accesses to the same area (the user has to do the 109 * checks by hand with "access_ok()") 110 */ 111 #define __put_user(x, ptr) \ 112 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 113 #define __get_user(x, ptr) \ 114 __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr))) 115 116 struct __large_struct { unsigned long buf[100]; }; 117 #define __m(x) ((struct __large_struct __user *)(x)) 118 119 #define __put_user_check(x, addr, size) ({ \ 120 register int __pu_ret; \ 121 if (__access_ok(addr, size)) { \ 122 switch (size) { \ 123 case 1: \ 124 __put_user_asm(x, b, addr, __pu_ret); \ 125 break; \ 126 case 2: \ 127 __put_user_asm(x, h, addr, __pu_ret); \ 128 break; \ 129 case 4: \ 130 __put_user_asm(x, , addr, __pu_ret); \ 131 break; \ 132 case 8: \ 133 __put_user_asm(x, d, addr, __pu_ret); \ 134 break; \ 135 default: \ 136 __pu_ret = __put_user_bad(); \ 137 break; \ 138 } \ 139 } else { \ 140 __pu_ret = -EFAULT; \ 141 } \ 142 __pu_ret; \ 143 }) 144 145 #define __put_user_nocheck(x, addr, size) ({ \ 146 register int __pu_ret; \ 147 switch (size) { \ 148 case 1: __put_user_asm(x, b, addr, __pu_ret); break; \ 149 case 2: __put_user_asm(x, h, addr, __pu_ret); break; \ 150 case 4: __put_user_asm(x, , addr, __pu_ret); break; \ 151 case 8: __put_user_asm(x, d, addr, __pu_ret); break; \ 152 default: __pu_ret = __put_user_bad(); break; \ 153 } \ 154 __pu_ret; \ 155 }) 156 157 #define __put_user_asm(x, size, addr, ret) \ 158 __asm__ __volatile__( \ 159 "/* Put user asm, inline. */\n" \ 160 "1:\t" "st"#size " %1, %2\n\t" \ 161 "clr %0\n" \ 162 "2:\n\n\t" \ 163 ".section .fixup,#alloc,#execinstr\n\t" \ 164 ".align 4\n" \ 165 "3:\n\t" \ 166 "b 2b\n\t" \ 167 " mov %3, %0\n\t" \ 168 ".previous\n\n\t" \ 169 ".section __ex_table,#alloc\n\t" \ 170 ".align 4\n\t" \ 171 ".word 1b, 3b\n\t" \ 172 ".previous\n\n\t" \ 173 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \ 174 "i" (-EFAULT)) 175 176 int __put_user_bad(void); 177 178 #define __get_user_check(x, addr, size, type) ({ \ 179 register int __gu_ret; \ 180 register unsigned long __gu_val; \ 181 if (__access_ok(addr, size)) { \ 182 switch (size) { \ 183 case 1: \ 184 __get_user_asm(__gu_val, ub, addr, __gu_ret); \ 185 break; \ 186 case 2: \ 187 __get_user_asm(__gu_val, uh, addr, __gu_ret); \ 188 break; \ 189 case 4: \ 190 __get_user_asm(__gu_val, , addr, __gu_ret); \ 191 break; \ 192 case 8: \ 193 __get_user_asm(__gu_val, d, addr, __gu_ret); \ 194 break; \ 195 default: \ 196 __gu_val = 0; \ 197 __gu_ret = __get_user_bad(); \ 198 break; \ 199 } \ 200 } else { \ 201 __gu_val = 0; \ 202 __gu_ret = -EFAULT; \ 203 } \ 204 x = (__force type) __gu_val; \ 205 __gu_ret; \ 206 }) 207 208 #define __get_user_nocheck(x, addr, size, type) ({ \ 209 register int __gu_ret; \ 210 register unsigned long __gu_val; \ 211 switch (size) { \ 212 case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break; \ 213 case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break; \ 214 case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break; \ 215 case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break; \ 216 default: \ 217 __gu_val = 0; \ 218 __gu_ret = __get_user_bad(); \ 219 break; \ 220 } \ 221 x = (__force type) __gu_val; \ 222 __gu_ret; \ 223 }) 224 225 #define __get_user_asm(x, size, addr, ret) \ 226 __asm__ __volatile__( \ 227 "/* Get user asm, inline. */\n" \ 228 "1:\t" "ld"#size " %2, %1\n\t" \ 229 "clr %0\n" \ 230 "2:\n\n\t" \ 231 ".section .fixup,#alloc,#execinstr\n\t" \ 232 ".align 4\n" \ 233 "3:\n\t" \ 234 "clr %1\n\t" \ 235 "b 2b\n\t" \ 236 " mov %3, %0\n\n\t" \ 237 ".previous\n\t" \ 238 ".section __ex_table,#alloc\n\t" \ 239 ".align 4\n\t" \ 240 ".word 1b, 3b\n\n\t" \ 241 ".previous\n\t" \ 242 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \ 243 "i" (-EFAULT)) 244 245 int __get_user_bad(void); 246 247 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size); 248 249 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n) 250 { 251 if (n && __access_ok((unsigned long) to, n)) { 252 check_object_size(from, n, true); 253 return __copy_user(to, (__force void __user *) from, n); 254 } else 255 return n; 256 } 257 258 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n) 259 { 260 check_object_size(from, n, true); 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 check_object_size(to, n, false); 268 return __copy_user((__force void __user *) to, from, n); 269 } else { 270 memset(to, 0, n); 271 return n; 272 } 273 } 274 275 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n) 276 { 277 return __copy_user((__force void __user *) to, from, n); 278 } 279 280 #define __copy_to_user_inatomic __copy_to_user 281 #define __copy_from_user_inatomic __copy_from_user 282 283 static inline unsigned long __clear_user(void __user *addr, unsigned long size) 284 { 285 unsigned long ret; 286 287 __asm__ __volatile__ ( 288 ".section __ex_table,#alloc\n\t" 289 ".align 4\n\t" 290 ".word 1f,3\n\t" 291 ".previous\n\t" 292 "mov %2, %%o1\n" 293 "1:\n\t" 294 "call __bzero\n\t" 295 " mov %1, %%o0\n\t" 296 "mov %%o0, %0\n" 297 : "=r" (ret) : "r" (addr), "r" (size) : 298 "o0", "o1", "o2", "o3", "o4", "o5", "o7", 299 "g1", "g2", "g3", "g4", "g5", "g7", "cc"); 300 301 return ret; 302 } 303 304 static inline unsigned long clear_user(void __user *addr, unsigned long n) 305 { 306 if (n && __access_ok((unsigned long) addr, n)) 307 return __clear_user(addr, n); 308 else 309 return n; 310 } 311 312 __must_check long strlen_user(const char __user *str); 313 __must_check long strnlen_user(const char __user *str, long n); 314 315 #endif /* __ASSEMBLY__ */ 316 317 #endif /* _ASM_UACCESS_H */ 318