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 /* 86 * These are the main single-value transfer routines. They automatically 87 * use the right size if we just have the right 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 uglyness from the user. 93 * 94 * The "__xxx" versions of the user access functions are versions that 95 * do not verify the address space, that must have been done previously 96 * with a separate "access_ok()" call (this is used when we do multiple 97 * accesses to the same area of user memory). 98 * 99 * As we use the same address space for kernel and user data on the 100 * PowerPC, we can just do these as direct assignments. (Of course, the 101 * exception handling means that it's no longer "just"...) 102 */ 103 #define get_user(x, ptr) \ 104 __get_user_check((x), (ptr), sizeof(*(ptr))) 105 #define put_user(x, ptr) \ 106 __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 107 108 #define __get_user(x, ptr) \ 109 __get_user_nocheck((x), (ptr), sizeof(*(ptr))) 110 #define __put_user(x, ptr) \ 111 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 112 113 extern long __put_user_bad(void); 114 115 #define __put_user_nocheck(x, ptr, size) \ 116 ({ \ 117 long __pu_err; \ 118 __put_user_size((x), (ptr), (size), __pu_err); \ 119 __pu_err; \ 120 }) 121 122 #define __put_user_check(x, ptr, size) \ 123 ({ \ 124 long __pu_err = -EFAULT; \ 125 __typeof__(*(ptr)) *__pu_addr = (ptr); \ 126 if (access_ok(VERIFY_WRITE, __pu_addr, size)) \ 127 __put_user_size((x), __pu_addr, (size), __pu_err); \ 128 __pu_err; \ 129 }) 130 131 #define __put_user_size(x, ptr, size, retval) \ 132 do { \ 133 retval = 0; \ 134 switch (size) { \ 135 case 1: __put_user_asm(x, ptr, retval, "l.sb"); break; \ 136 case 2: __put_user_asm(x, ptr, retval, "l.sh"); break; \ 137 case 4: __put_user_asm(x, ptr, retval, "l.sw"); break; \ 138 case 8: __put_user_asm2(x, ptr, retval); break; \ 139 default: __put_user_bad(); \ 140 } \ 141 } while (0) 142 143 struct __large_struct { 144 unsigned long buf[100]; 145 }; 146 #define __m(x) (*(struct __large_struct *)(x)) 147 148 /* 149 * We don't tell gcc that we are accessing memory, but this is OK 150 * because we do not write to any memory gcc knows about, so there 151 * are no aliasing issues. 152 */ 153 #define __put_user_asm(x, addr, err, op) \ 154 __asm__ __volatile__( \ 155 "1: "op" 0(%2),%1\n" \ 156 "2:\n" \ 157 ".section .fixup,\"ax\"\n" \ 158 "3: l.addi %0,r0,%3\n" \ 159 " l.j 2b\n" \ 160 " l.nop\n" \ 161 ".previous\n" \ 162 ".section __ex_table,\"a\"\n" \ 163 " .align 2\n" \ 164 " .long 1b,3b\n" \ 165 ".previous" \ 166 : "=r"(err) \ 167 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err)) 168 169 #define __put_user_asm2(x, addr, err) \ 170 __asm__ __volatile__( \ 171 "1: l.sw 0(%2),%1\n" \ 172 "2: l.sw 4(%2),%H1\n" \ 173 "3:\n" \ 174 ".section .fixup,\"ax\"\n" \ 175 "4: l.addi %0,r0,%3\n" \ 176 " l.j 3b\n" \ 177 " l.nop\n" \ 178 ".previous\n" \ 179 ".section __ex_table,\"a\"\n" \ 180 " .align 2\n" \ 181 " .long 1b,4b\n" \ 182 " .long 2b,4b\n" \ 183 ".previous" \ 184 : "=r"(err) \ 185 : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err)) 186 187 #define __get_user_nocheck(x, ptr, size) \ 188 ({ \ 189 long __gu_err, __gu_val; \ 190 __get_user_size(__gu_val, (ptr), (size), __gu_err); \ 191 (x) = (__force __typeof__(*(ptr)))__gu_val; \ 192 __gu_err; \ 193 }) 194 195 #define __get_user_check(x, ptr, size) \ 196 ({ \ 197 long __gu_err = -EFAULT, __gu_val = 0; \ 198 const __typeof__(*(ptr)) * __gu_addr = (ptr); \ 199 if (access_ok(VERIFY_READ, __gu_addr, size)) \ 200 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \ 201 (x) = (__force __typeof__(*(ptr)))__gu_val; \ 202 __gu_err; \ 203 }) 204 205 extern long __get_user_bad(void); 206 207 #define __get_user_size(x, ptr, size, retval) \ 208 do { \ 209 retval = 0; \ 210 switch (size) { \ 211 case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break; \ 212 case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break; \ 213 case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break; \ 214 case 8: __get_user_asm2(x, ptr, retval); \ 215 default: (x) = __get_user_bad(); \ 216 } \ 217 } while (0) 218 219 #define __get_user_asm(x, addr, err, op) \ 220 __asm__ __volatile__( \ 221 "1: "op" %1,0(%2)\n" \ 222 "2:\n" \ 223 ".section .fixup,\"ax\"\n" \ 224 "3: l.addi %0,r0,%3\n" \ 225 " l.addi %1,r0,0\n" \ 226 " l.j 2b\n" \ 227 " l.nop\n" \ 228 ".previous\n" \ 229 ".section __ex_table,\"a\"\n" \ 230 " .align 2\n" \ 231 " .long 1b,3b\n" \ 232 ".previous" \ 233 : "=r"(err), "=r"(x) \ 234 : "r"(addr), "i"(-EFAULT), "0"(err)) 235 236 #define __get_user_asm2(x, addr, err) \ 237 __asm__ __volatile__( \ 238 "1: l.lwz %1,0(%2)\n" \ 239 "2: l.lwz %H1,4(%2)\n" \ 240 "3:\n" \ 241 ".section .fixup,\"ax\"\n" \ 242 "4: l.addi %0,r0,%3\n" \ 243 " l.addi %1,r0,0\n" \ 244 " l.addi %H1,r0,0\n" \ 245 " l.j 3b\n" \ 246 " l.nop\n" \ 247 ".previous\n" \ 248 ".section __ex_table,\"a\"\n" \ 249 " .align 2\n" \ 250 " .long 1b,4b\n" \ 251 " .long 2b,4b\n" \ 252 ".previous" \ 253 : "=r"(err), "=&r"(x) \ 254 : "r"(addr), "i"(-EFAULT), "0"(err)) 255 256 /* more complex routines */ 257 258 extern unsigned long __must_check 259 __copy_tofrom_user(void *to, const void *from, unsigned long size); 260 261 #define __copy_from_user(to, from, size) \ 262 __copy_tofrom_user(to, from, size) 263 #define __copy_to_user(to, from, size) \ 264 __copy_tofrom_user(to, from, size) 265 266 #define __copy_to_user_inatomic __copy_to_user 267 #define __copy_from_user_inatomic __copy_from_user 268 269 static inline unsigned long 270 copy_from_user(void *to, const void *from, unsigned long n) 271 { 272 unsigned long res = n; 273 274 if (likely(access_ok(VERIFY_READ, from, n))) 275 res = __copy_tofrom_user(to, from, n); 276 if (unlikely(res)) 277 memset(to + (n - res), 0, res); 278 return res; 279 } 280 281 static inline unsigned long 282 copy_to_user(void *to, const void *from, unsigned long n) 283 { 284 if (likely(access_ok(VERIFY_WRITE, to, n))) 285 n = __copy_tofrom_user(to, from, n); 286 return n; 287 } 288 289 extern unsigned long __clear_user(void *addr, unsigned long size); 290 291 static inline __must_check unsigned long 292 clear_user(void *addr, unsigned long size) 293 { 294 if (likely(access_ok(VERIFY_WRITE, addr, size))) 295 size = __clear_user(addr, size); 296 return size; 297 } 298 299 #define user_addr_max() \ 300 (segment_eq(get_fs(), USER_DS) ? TASK_SIZE : ~0UL) 301 302 extern long strncpy_from_user(char *dest, const char __user *src, long count); 303 304 extern __must_check long strlen_user(const char __user *str); 305 extern __must_check long strnlen_user(const char __user *str, long n); 306 307 #endif /* __ASM_OPENRISC_UACCESS_H */ 308