1 /* 2 * OpenRISC Linux 3 * 4 * Linux architectural port borrowing liberally from similar works of 5 * others. All original copyrights apply as per the original source 6 * declaration. 7 * 8 * OpenRISC implementation: 9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> 10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> 11 * et al. 12 * 13 * This program is free software; you can redistribute it and/or modify 14 * it under the terms of the GNU General Public License as published by 15 * the Free Software Foundation; either version 2 of the License, or 16 * (at your option) any later version. 17 */ 18 19 #ifndef __ASM_OPENRISC_UACCESS_H 20 #define __ASM_OPENRISC_UACCESS_H 21 22 /* 23 * User space memory access functions 24 */ 25 #include <linux/errno.h> 26 #include <linux/thread_info.h> 27 #include <linux/prefetch.h> 28 #include <linux/string.h> 29 #include <linux/thread_info.h> 30 #include <asm/page.h> 31 32 #define VERIFY_READ 0 33 #define VERIFY_WRITE 1 34 35 /* 36 * The fs value determines whether argument validity checking should be 37 * performed or not. If get_fs() == USER_DS, checking is performed, with 38 * get_fs() == KERNEL_DS, checking is bypassed. 39 * 40 * For historical reasons, these macros are grossly misnamed. 41 */ 42 43 /* addr_limit is the maximum accessible address for the task. we misuse 44 * the KERNEL_DS and USER_DS values to both assign and compare the 45 * addr_limit values through the equally misnamed get/set_fs macros. 46 * (see above) 47 */ 48 49 #define KERNEL_DS (~0UL) 50 #define get_ds() (KERNEL_DS) 51 52 #define USER_DS (TASK_SIZE) 53 #define get_fs() (current_thread_info()->addr_limit) 54 #define set_fs(x) (current_thread_info()->addr_limit = (x)) 55 56 #define segment_eq(a, b) ((a) == (b)) 57 58 /* Ensure that the range from addr to addr+size is all within the process' 59 * address space 60 */ 61 #define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()-size)) 62 63 /* Ensure that addr is below task's addr_limit */ 64 #define __addr_ok(addr) ((unsigned long) addr < get_fs()) 65 66 #define access_ok(type, addr, size) \ 67 __range_ok((unsigned long)addr, (unsigned long)size) 68 69 /* 70 * The exception table consists of pairs of addresses: the first is the 71 * address of an instruction that is allowed to fault, and the second is 72 * the address at which the program should continue. No registers are 73 * modified, so it is entirely up to the continuation code to figure out 74 * what to do. 75 * 76 * All the routines below use bits of fixup code that are out of line 77 * with the main instruction path. This means when everything is well, 78 * we don't even have to jump over them. Further, they do not intrude 79 * on our cache or tlb entries. 80 */ 81 82 struct exception_table_entry { 83 unsigned long insn, fixup; 84 }; 85 86 /* Returns 0 if exception not found and fixup otherwise. */ 87 extern unsigned long search_exception_table(unsigned long); 88 extern void sort_exception_table(void); 89 90 /* 91 * These are the main single-value transfer routines. They automatically 92 * use the right size if we just have the right pointer type. 93 * 94 * This gets kind of ugly. We want to return _two_ values in "get_user()" 95 * and yet we don't want to do any pointers, because that is too much 96 * of a performance impact. Thus we have a few rather ugly macros here, 97 * and hide all the uglyness from the user. 98 * 99 * The "__xxx" versions of the user access functions are versions that 100 * do not verify the address space, that must have been done previously 101 * with a separate "access_ok()" call (this is used when we do multiple 102 * accesses to the same area of user memory). 103 * 104 * As we use the same address space for kernel and user data on the 105 * PowerPC, we can just do these as direct assignments. (Of course, the 106 * exception handling means that it's no longer "just"...) 107 */ 108 #define get_user(x, ptr) \ 109 __get_user_check((x), (ptr), sizeof(*(ptr))) 110 #define put_user(x, ptr) \ 111 __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 112 113 #define __get_user(x, ptr) \ 114 __get_user_nocheck((x), (ptr), sizeof(*(ptr))) 115 #define __put_user(x, ptr) \ 116 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 117 118 extern long __put_user_bad(void); 119 120 #define __put_user_nocheck(x, ptr, size) \ 121 ({ \ 122 long __pu_err; \ 123 __put_user_size((x), (ptr), (size), __pu_err); \ 124 __pu_err; \ 125 }) 126 127 #define __put_user_check(x, ptr, size) \ 128 ({ \ 129 long __pu_err = -EFAULT; \ 130 __typeof__(*(ptr)) *__pu_addr = (ptr); \ 131 if (access_ok(VERIFY_WRITE, __pu_addr, size)) \ 132 __put_user_size((x), __pu_addr, (size), __pu_err); \ 133 __pu_err; \ 134 }) 135 136 #define __put_user_size(x, ptr, size, retval) \ 137 do { \ 138 retval = 0; \ 139 switch (size) { \ 140 case 1: __put_user_asm(x, ptr, retval, "l.sb"); break; \ 141 case 2: __put_user_asm(x, ptr, retval, "l.sh"); break; \ 142 case 4: __put_user_asm(x, ptr, retval, "l.sw"); break; \ 143 case 8: __put_user_asm2(x, ptr, retval); break; \ 144 default: __put_user_bad(); \ 145 } \ 146 } while (0) 147 148 struct __large_struct { 149 unsigned long buf[100]; 150 }; 151 #define __m(x) (*(struct __large_struct *)(x)) 152 153 /* 154 * We don't tell gcc that we are accessing memory, but this is OK 155 * because we do not write to any memory gcc knows about, so there 156 * are no aliasing issues. 157 */ 158 #define __put_user_asm(x, addr, err, op) \ 159 __asm__ __volatile__( \ 160 "1: "op" 0(%2),%1\n" \ 161 "2:\n" \ 162 ".section .fixup,\"ax\"\n" \ 163 "3: l.addi %0,r0,%3\n" \ 164 " l.j 2b\n" \ 165 " l.nop\n" \ 166 ".previous\n" \ 167 ".section __ex_table,\"a\"\n" \ 168 " .align 2\n" \ 169 " .long 1b,3b\n" \ 170 ".previous" \ 171 : "=r"(err) \ 172 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err)) 173 174 #define __put_user_asm2(x, addr, err) \ 175 __asm__ __volatile__( \ 176 "1: l.sw 0(%2),%1\n" \ 177 "2: l.sw 4(%2),%H1\n" \ 178 "3:\n" \ 179 ".section .fixup,\"ax\"\n" \ 180 "4: l.addi %0,r0,%3\n" \ 181 " l.j 3b\n" \ 182 " l.nop\n" \ 183 ".previous\n" \ 184 ".section __ex_table,\"a\"\n" \ 185 " .align 2\n" \ 186 " .long 1b,4b\n" \ 187 " .long 2b,4b\n" \ 188 ".previous" \ 189 : "=r"(err) \ 190 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err)) 191 192 #define __get_user_nocheck(x, ptr, size) \ 193 ({ \ 194 long __gu_err, __gu_val; \ 195 __get_user_size(__gu_val, (ptr), (size), __gu_err); \ 196 (x) = (__typeof__(*(ptr)))__gu_val; \ 197 __gu_err; \ 198 }) 199 200 #define __get_user_check(x, ptr, size) \ 201 ({ \ 202 long __gu_err = -EFAULT, __gu_val = 0; \ 203 const __typeof__(*(ptr)) * __gu_addr = (ptr); \ 204 if (access_ok(VERIFY_READ, __gu_addr, size)) \ 205 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \ 206 (x) = (__typeof__(*(ptr)))__gu_val; \ 207 __gu_err; \ 208 }) 209 210 extern long __get_user_bad(void); 211 212 #define __get_user_size(x, ptr, size, retval) \ 213 do { \ 214 retval = 0; \ 215 switch (size) { \ 216 case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break; \ 217 case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break; \ 218 case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break; \ 219 case 8: __get_user_asm2(x, ptr, retval); \ 220 default: (x) = __get_user_bad(); \ 221 } \ 222 } while (0) 223 224 #define __get_user_asm(x, addr, err, op) \ 225 __asm__ __volatile__( \ 226 "1: "op" %1,0(%2)\n" \ 227 "2:\n" \ 228 ".section .fixup,\"ax\"\n" \ 229 "3: l.addi %0,r0,%3\n" \ 230 " l.addi %1,r0,0\n" \ 231 " l.j 2b\n" \ 232 " l.nop\n" \ 233 ".previous\n" \ 234 ".section __ex_table,\"a\"\n" \ 235 " .align 2\n" \ 236 " .long 1b,3b\n" \ 237 ".previous" \ 238 : "=r"(err), "=r"(x) \ 239 : "r"(addr), "i"(-EFAULT), "0"(err)) 240 241 #define __get_user_asm2(x, addr, err) \ 242 __asm__ __volatile__( \ 243 "1: l.lwz %1,0(%2)\n" \ 244 "2: l.lwz %H1,4(%2)\n" \ 245 "3:\n" \ 246 ".section .fixup,\"ax\"\n" \ 247 "4: l.addi %0,r0,%3\n" \ 248 " l.addi %1,r0,0\n" \ 249 " l.addi %H1,r0,0\n" \ 250 " l.j 3b\n" \ 251 " l.nop\n" \ 252 ".previous\n" \ 253 ".section __ex_table,\"a\"\n" \ 254 " .align 2\n" \ 255 " .long 1b,4b\n" \ 256 " .long 2b,4b\n" \ 257 ".previous" \ 258 : "=r"(err), "=&r"(x) \ 259 : "r"(addr), "i"(-EFAULT), "0"(err)) 260 261 /* more complex routines */ 262 263 extern unsigned long __must_check 264 __copy_tofrom_user(void *to, const void *from, unsigned long size); 265 266 #define __copy_from_user(to, from, size) \ 267 __copy_tofrom_user(to, from, size) 268 #define __copy_to_user(to, from, size) \ 269 __copy_tofrom_user(to, from, size) 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 275 copy_from_user(void *to, const void *from, unsigned long n) 276 { 277 unsigned long over; 278 279 if (access_ok(VERIFY_READ, from, n)) 280 return __copy_tofrom_user(to, from, n); 281 if ((unsigned long)from < TASK_SIZE) { 282 over = (unsigned long)from + n - TASK_SIZE; 283 return __copy_tofrom_user(to, from, n - over) + over; 284 } 285 return n; 286 } 287 288 static inline unsigned long 289 copy_to_user(void *to, const void *from, unsigned long n) 290 { 291 unsigned long over; 292 293 if (access_ok(VERIFY_WRITE, to, n)) 294 return __copy_tofrom_user(to, from, n); 295 if ((unsigned long)to < TASK_SIZE) { 296 over = (unsigned long)to + n - TASK_SIZE; 297 return __copy_tofrom_user(to, from, n - over) + over; 298 } 299 return n; 300 } 301 302 extern unsigned long __clear_user(void *addr, unsigned long size); 303 304 static inline __must_check unsigned long 305 clear_user(void *addr, unsigned long size) 306 { 307 308 if (access_ok(VERIFY_WRITE, addr, size)) 309 return __clear_user(addr, size); 310 if ((unsigned long)addr < TASK_SIZE) { 311 unsigned long over = (unsigned long)addr + size - TASK_SIZE; 312 return __clear_user(addr, size - over) + over; 313 } 314 return size; 315 } 316 317 extern int __strncpy_from_user(char *dst, const char *src, long count); 318 319 static inline long strncpy_from_user(char *dst, const char *src, long count) 320 { 321 if (access_ok(VERIFY_READ, src, 1)) 322 return __strncpy_from_user(dst, src, count); 323 return -EFAULT; 324 } 325 326 /* 327 * Return the size of a string (including the ending 0) 328 * 329 * Return 0 for error 330 */ 331 332 extern int __strnlen_user(const char *str, long len, unsigned long top); 333 334 /* 335 * Returns the length of the string at str (including the null byte), 336 * or 0 if we hit a page we can't access, 337 * or something > len if we didn't find a null byte. 338 * 339 * The `top' parameter to __strnlen_user is to make sure that 340 * we can never overflow from the user area into kernel space. 341 */ 342 static inline long strnlen_user(const char __user *str, long len) 343 { 344 unsigned long top = (unsigned long)get_fs(); 345 unsigned long res = 0; 346 347 if (__addr_ok(str)) 348 res = __strnlen_user(str, len, top); 349 350 return res; 351 } 352 353 #define strlen_user(str) strnlen_user(str, TASK_SIZE-1) 354 355 #endif /* __ASM_OPENRISC_UACCESS_H */ 356