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 <asm/page.h> 30 31 #define VERIFY_READ 0 32 #define VERIFY_WRITE 1 33 34 /* 35 * The fs value determines whether argument validity checking should be 36 * performed or not. If get_fs() == USER_DS, checking is performed, with 37 * get_fs() == KERNEL_DS, checking is bypassed. 38 * 39 * For historical reasons, these macros are grossly misnamed. 40 */ 41 42 /* addr_limit is the maximum accessible address for the task. we misuse 43 * the KERNEL_DS and USER_DS values to both assign and compare the 44 * addr_limit values through the equally misnamed get/set_fs macros. 45 * (see above) 46 */ 47 48 #define KERNEL_DS (~0UL) 49 #define get_ds() (KERNEL_DS) 50 51 #define USER_DS (TASK_SIZE) 52 #define get_fs() (current_thread_info()->addr_limit) 53 #define set_fs(x) (current_thread_info()->addr_limit = (x)) 54 55 #define segment_eq(a, b) ((a) == (b)) 56 57 /* Ensure that the range from addr to addr+size is all within the process' 58 * address space 59 */ 60 #define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()-size)) 61 62 /* Ensure that addr is below task's addr_limit */ 63 #define __addr_ok(addr) ((unsigned long) addr < get_fs()) 64 65 #define access_ok(type, addr, size) \ 66 __range_ok((unsigned long)addr, (unsigned long)size) 67 68 /* 69 * The exception table consists of pairs of addresses: the first is the 70 * address of an instruction that is allowed to fault, and the second is 71 * the address at which the program should continue. No registers are 72 * modified, so it is entirely up to the continuation code to figure out 73 * what to do. 74 * 75 * All the routines below use bits of fixup code that are out of line 76 * with the main instruction path. This means when everything is well, 77 * we don't even have to jump over them. Further, they do not intrude 78 * on our cache or tlb entries. 79 */ 80 81 struct exception_table_entry { 82 unsigned long insn, fixup; 83 }; 84 85 /* Returns 0 if exception not found and fixup otherwise. */ 86 extern unsigned long search_exception_table(unsigned long); 87 extern void sort_exception_table(void); 88 89 /* 90 * These are the main single-value transfer routines. They automatically 91 * use the right size if we just have the right pointer type. 92 * 93 * This gets kind of ugly. We want to return _two_ values in "get_user()" 94 * and yet we don't want to do any pointers, because that is too much 95 * of a performance impact. Thus we have a few rather ugly macros here, 96 * and hide all the uglyness from the user. 97 * 98 * The "__xxx" versions of the user access functions are versions that 99 * do not verify the address space, that must have been done previously 100 * with a separate "access_ok()" call (this is used when we do multiple 101 * accesses to the same area of user memory). 102 * 103 * As we use the same address space for kernel and user data on the 104 * PowerPC, we can just do these as direct assignments. (Of course, the 105 * exception handling means that it's no longer "just"...) 106 */ 107 #define get_user(x, ptr) \ 108 __get_user_check((x), (ptr), sizeof(*(ptr))) 109 #define put_user(x, ptr) \ 110 __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 111 112 #define __get_user(x, ptr) \ 113 __get_user_nocheck((x), (ptr), sizeof(*(ptr))) 114 #define __put_user(x, ptr) \ 115 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 116 117 extern long __put_user_bad(void); 118 119 #define __put_user_nocheck(x, ptr, size) \ 120 ({ \ 121 long __pu_err; \ 122 __put_user_size((x), (ptr), (size), __pu_err); \ 123 __pu_err; \ 124 }) 125 126 #define __put_user_check(x, ptr, size) \ 127 ({ \ 128 long __pu_err = -EFAULT; \ 129 __typeof__(*(ptr)) *__pu_addr = (ptr); \ 130 if (access_ok(VERIFY_WRITE, __pu_addr, size)) \ 131 __put_user_size((x), __pu_addr, (size), __pu_err); \ 132 __pu_err; \ 133 }) 134 135 #define __put_user_size(x, ptr, size, retval) \ 136 do { \ 137 retval = 0; \ 138 switch (size) { \ 139 case 1: __put_user_asm(x, ptr, retval, "l.sb"); break; \ 140 case 2: __put_user_asm(x, ptr, retval, "l.sh"); break; \ 141 case 4: __put_user_asm(x, ptr, retval, "l.sw"); break; \ 142 case 8: __put_user_asm2(x, ptr, retval); break; \ 143 default: __put_user_bad(); \ 144 } \ 145 } while (0) 146 147 struct __large_struct { 148 unsigned long buf[100]; 149 }; 150 #define __m(x) (*(struct __large_struct *)(x)) 151 152 /* 153 * We don't tell gcc that we are accessing memory, but this is OK 154 * because we do not write to any memory gcc knows about, so there 155 * are no aliasing issues. 156 */ 157 #define __put_user_asm(x, addr, err, op) \ 158 __asm__ __volatile__( \ 159 "1: "op" 0(%2),%1\n" \ 160 "2:\n" \ 161 ".section .fixup,\"ax\"\n" \ 162 "3: l.addi %0,r0,%3\n" \ 163 " l.j 2b\n" \ 164 " l.nop\n" \ 165 ".previous\n" \ 166 ".section __ex_table,\"a\"\n" \ 167 " .align 2\n" \ 168 " .long 1b,3b\n" \ 169 ".previous" \ 170 : "=r"(err) \ 171 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err)) 172 173 #define __put_user_asm2(x, addr, err) \ 174 __asm__ __volatile__( \ 175 "1: l.sw 0(%2),%1\n" \ 176 "2: l.sw 4(%2),%H1\n" \ 177 "3:\n" \ 178 ".section .fixup,\"ax\"\n" \ 179 "4: l.addi %0,r0,%3\n" \ 180 " l.j 3b\n" \ 181 " l.nop\n" \ 182 ".previous\n" \ 183 ".section __ex_table,\"a\"\n" \ 184 " .align 2\n" \ 185 " .long 1b,4b\n" \ 186 " .long 2b,4b\n" \ 187 ".previous" \ 188 : "=r"(err) \ 189 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err)) 190 191 #define __get_user_nocheck(x, ptr, size) \ 192 ({ \ 193 long __gu_err, __gu_val; \ 194 __get_user_size(__gu_val, (ptr), (size), __gu_err); \ 195 (x) = (__force __typeof__(*(ptr)))__gu_val; \ 196 __gu_err; \ 197 }) 198 199 #define __get_user_check(x, ptr, size) \ 200 ({ \ 201 long __gu_err = -EFAULT, __gu_val = 0; \ 202 const __typeof__(*(ptr)) * __gu_addr = (ptr); \ 203 if (access_ok(VERIFY_READ, __gu_addr, size)) \ 204 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \ 205 (x) = (__force __typeof__(*(ptr)))__gu_val; \ 206 __gu_err; \ 207 }) 208 209 extern long __get_user_bad(void); 210 211 #define __get_user_size(x, ptr, size, retval) \ 212 do { \ 213 retval = 0; \ 214 switch (size) { \ 215 case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break; \ 216 case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break; \ 217 case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break; \ 218 case 8: __get_user_asm2(x, ptr, retval); \ 219 default: (x) = __get_user_bad(); \ 220 } \ 221 } while (0) 222 223 #define __get_user_asm(x, addr, err, op) \ 224 __asm__ __volatile__( \ 225 "1: "op" %1,0(%2)\n" \ 226 "2:\n" \ 227 ".section .fixup,\"ax\"\n" \ 228 "3: l.addi %0,r0,%3\n" \ 229 " l.addi %1,r0,0\n" \ 230 " l.j 2b\n" \ 231 " l.nop\n" \ 232 ".previous\n" \ 233 ".section __ex_table,\"a\"\n" \ 234 " .align 2\n" \ 235 " .long 1b,3b\n" \ 236 ".previous" \ 237 : "=r"(err), "=r"(x) \ 238 : "r"(addr), "i"(-EFAULT), "0"(err)) 239 240 #define __get_user_asm2(x, addr, err) \ 241 __asm__ __volatile__( \ 242 "1: l.lwz %1,0(%2)\n" \ 243 "2: l.lwz %H1,4(%2)\n" \ 244 "3:\n" \ 245 ".section .fixup,\"ax\"\n" \ 246 "4: l.addi %0,r0,%3\n" \ 247 " l.addi %1,r0,0\n" \ 248 " l.addi %H1,r0,0\n" \ 249 " l.j 3b\n" \ 250 " l.nop\n" \ 251 ".previous\n" \ 252 ".section __ex_table,\"a\"\n" \ 253 " .align 2\n" \ 254 " .long 1b,4b\n" \ 255 " .long 2b,4b\n" \ 256 ".previous" \ 257 : "=r"(err), "=&r"(x) \ 258 : "r"(addr), "i"(-EFAULT), "0"(err)) 259 260 /* more complex routines */ 261 262 extern unsigned long __must_check 263 __copy_tofrom_user(void *to, const void *from, unsigned long size); 264 265 #define __copy_from_user(to, from, size) \ 266 __copy_tofrom_user(to, from, size) 267 #define __copy_to_user(to, from, size) \ 268 __copy_tofrom_user(to, from, size) 269 270 #define __copy_to_user_inatomic __copy_to_user 271 #define __copy_from_user_inatomic __copy_from_user 272 273 static inline unsigned long 274 copy_from_user(void *to, const void *from, unsigned long n) 275 { 276 unsigned long over; 277 278 if (access_ok(VERIFY_READ, from, n)) 279 return __copy_tofrom_user(to, from, n); 280 if ((unsigned long)from < TASK_SIZE) { 281 over = (unsigned long)from + n - TASK_SIZE; 282 return __copy_tofrom_user(to, from, n - over) + over; 283 } 284 return n; 285 } 286 287 static inline unsigned long 288 copy_to_user(void *to, const void *from, unsigned long n) 289 { 290 unsigned long over; 291 292 if (access_ok(VERIFY_WRITE, to, n)) 293 return __copy_tofrom_user(to, from, n); 294 if ((unsigned long)to < TASK_SIZE) { 295 over = (unsigned long)to + n - TASK_SIZE; 296 return __copy_tofrom_user(to, from, n - over) + over; 297 } 298 return n; 299 } 300 301 extern unsigned long __clear_user(void *addr, unsigned long size); 302 303 static inline __must_check unsigned long 304 clear_user(void *addr, unsigned long size) 305 { 306 307 if (access_ok(VERIFY_WRITE, addr, size)) 308 return __clear_user(addr, size); 309 if ((unsigned long)addr < TASK_SIZE) { 310 unsigned long over = (unsigned long)addr + size - TASK_SIZE; 311 return __clear_user(addr, size - over) + over; 312 } 313 return size; 314 } 315 316 #define user_addr_max() \ 317 (segment_eq(get_fs(), USER_DS) ? TASK_SIZE : ~0UL) 318 319 extern long strncpy_from_user(char *dest, const char __user *src, long count); 320 321 extern __must_check long strlen_user(const char __user *str); 322 extern __must_check long strnlen_user(const char __user *str, long n); 323 324 #endif /* __ASM_OPENRISC_UACCESS_H */ 325