1/* 2 * linux/include/asm-arm/uaccess.h 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8#ifndef _ASMARM_UACCESS_H 9#define _ASMARM_UACCESS_H 10 11/* 12 * User space memory access functions 13 */ 14#include <linux/sched.h> 15#include <asm/errno.h> 16#include <asm/memory.h> 17#include <asm/domain.h> 18#include <asm/system.h> 19 20#define VERIFY_READ 0 21#define VERIFY_WRITE 1 22 23/* 24 * The exception table consists of pairs of addresses: the first is the 25 * address of an instruction that is allowed to fault, and the second is 26 * the address at which the program should continue. No registers are 27 * modified, so it is entirely up to the continuation code to figure out 28 * what to do. 29 * 30 * All the routines below use bits of fixup code that are out of line 31 * with the main instruction path. This means when everything is well, 32 * we don't even have to jump over them. Further, they do not intrude 33 * on our cache or tlb entries. 34 */ 35 36struct exception_table_entry 37{ 38 unsigned long insn, fixup; 39}; 40 41extern int fixup_exception(struct pt_regs *regs); 42 43/* 44 * These two are intentionally not defined anywhere - if the kernel 45 * code generates any references to them, that's a bug. 46 */ 47extern int __get_user_bad(void); 48extern int __put_user_bad(void); 49 50/* 51 * Note that this is actually 0x1,0000,0000 52 */ 53#define KERNEL_DS 0x00000000 54#define get_ds() (KERNEL_DS) 55 56#ifdef CONFIG_MMU 57 58#define USER_DS TASK_SIZE 59#define get_fs() (current_thread_info()->addr_limit) 60 61static inline void set_fs(mm_segment_t fs) 62{ 63 current_thread_info()->addr_limit = fs; 64 modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER); 65} 66 67#define segment_eq(a,b) ((a) == (b)) 68 69#define __addr_ok(addr) ({ \ 70 unsigned long flag; \ 71 __asm__("cmp %2, %0; movlo %0, #0" \ 72 : "=&r" (flag) \ 73 : "0" (current_thread_info()->addr_limit), "r" (addr) \ 74 : "cc"); \ 75 (flag == 0); }) 76 77/* We use 33-bit arithmetic here... */ 78#define __range_ok(addr,size) ({ \ 79 unsigned long flag, sum; \ 80 __chk_user_ptr(addr); \ 81 __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \ 82 : "=&r" (flag), "=&r" (sum) \ 83 : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \ 84 : "cc"); \ 85 flag; }) 86 87/* 88 * Single-value transfer routines. They automatically use the right 89 * size if we just have the right pointer type. Note that the functions 90 * which read from user space (*get_*) need to take care not to leak 91 * kernel data even if the calling code is buggy and fails to check 92 * the return value. This means zeroing out the destination variable 93 * or buffer on error. Normally this is done out of line by the 94 * fixup code, but there are a few places where it intrudes on the 95 * main code path. When we only write to user space, there is no 96 * problem. 97 */ 98extern int __get_user_1(void *); 99extern int __get_user_2(void *); 100extern int __get_user_4(void *); 101 102#define __get_user_x(__r2,__p,__e,__s,__i...) \ 103 __asm__ __volatile__ ( \ 104 __asmeq("%0", "r0") __asmeq("%1", "r2") \ 105 "bl __get_user_" #__s \ 106 : "=&r" (__e), "=r" (__r2) \ 107 : "0" (__p) \ 108 : __i, "cc") 109 110#define get_user(x,p) \ 111 ({ \ 112 const register typeof(*(p)) __user *__p asm("r0") = (p);\ 113 register unsigned int __r2 asm("r2"); \ 114 register int __e asm("r0"); \ 115 switch (sizeof(*(__p))) { \ 116 case 1: \ 117 __get_user_x(__r2, __p, __e, 1, "lr"); \ 118 break; \ 119 case 2: \ 120 __get_user_x(__r2, __p, __e, 2, "r3", "lr"); \ 121 break; \ 122 case 4: \ 123 __get_user_x(__r2, __p, __e, 4, "lr"); \ 124 break; \ 125 default: __e = __get_user_bad(); break; \ 126 } \ 127 x = (typeof(*(p))) __r2; \ 128 __e; \ 129 }) 130 131extern int __put_user_1(void *, unsigned int); 132extern int __put_user_2(void *, unsigned int); 133extern int __put_user_4(void *, unsigned int); 134extern int __put_user_8(void *, unsigned long long); 135 136#define __put_user_x(__r2,__p,__e,__s) \ 137 __asm__ __volatile__ ( \ 138 __asmeq("%0", "r0") __asmeq("%2", "r2") \ 139 "bl __put_user_" #__s \ 140 : "=&r" (__e) \ 141 : "0" (__p), "r" (__r2) \ 142 : "ip", "lr", "cc") 143 144#define put_user(x,p) \ 145 ({ \ 146 const register typeof(*(p)) __r2 asm("r2") = (x); \ 147 const register typeof(*(p)) __user *__p asm("r0") = (p);\ 148 register int __e asm("r0"); \ 149 switch (sizeof(*(__p))) { \ 150 case 1: \ 151 __put_user_x(__r2, __p, __e, 1); \ 152 break; \ 153 case 2: \ 154 __put_user_x(__r2, __p, __e, 2); \ 155 break; \ 156 case 4: \ 157 __put_user_x(__r2, __p, __e, 4); \ 158 break; \ 159 case 8: \ 160 __put_user_x(__r2, __p, __e, 8); \ 161 break; \ 162 default: __e = __put_user_bad(); break; \ 163 } \ 164 __e; \ 165 }) 166 167#else /* CONFIG_MMU */ 168 169/* 170 * uClinux has only one addr space, so has simplified address limits. 171 */ 172#define USER_DS KERNEL_DS 173 174#define segment_eq(a,b) (1) 175#define __addr_ok(addr) (1) 176#define __range_ok(addr,size) (0) 177#define get_fs() (KERNEL_DS) 178 179static inline void set_fs(mm_segment_t fs) 180{ 181} 182 183#define get_user(x,p) __get_user(x,p) 184#define put_user(x,p) __put_user(x,p) 185 186#endif /* CONFIG_MMU */ 187 188#define access_ok(type,addr,size) (__range_ok(addr,size) == 0) 189 190/* 191 * The "__xxx" versions of the user access functions do not verify the 192 * address space - it must have been done previously with a separate 193 * "access_ok()" call. 194 * 195 * The "xxx_error" versions set the third argument to EFAULT if an 196 * error occurs, and leave it unchanged on success. Note that these 197 * versions are void (ie, don't return a value as such). 198 */ 199#define __get_user(x,ptr) \ 200({ \ 201 long __gu_err = 0; \ 202 __get_user_err((x),(ptr),__gu_err); \ 203 __gu_err; \ 204}) 205 206#define __get_user_error(x,ptr,err) \ 207({ \ 208 __get_user_err((x),(ptr),err); \ 209 (void) 0; \ 210}) 211 212#define __get_user_err(x,ptr,err) \ 213do { \ 214 unsigned long __gu_addr = (unsigned long)(ptr); \ 215 unsigned long __gu_val; \ 216 __chk_user_ptr(ptr); \ 217 switch (sizeof(*(ptr))) { \ 218 case 1: __get_user_asm_byte(__gu_val,__gu_addr,err); break; \ 219 case 2: __get_user_asm_half(__gu_val,__gu_addr,err); break; \ 220 case 4: __get_user_asm_word(__gu_val,__gu_addr,err); break; \ 221 default: (__gu_val) = __get_user_bad(); \ 222 } \ 223 (x) = (__typeof__(*(ptr)))__gu_val; \ 224} while (0) 225 226#define __get_user_asm_byte(x,addr,err) \ 227 __asm__ __volatile__( \ 228 "1: ldrbt %1,[%2],#0\n" \ 229 "2:\n" \ 230 " .section .fixup,\"ax\"\n" \ 231 " .align 2\n" \ 232 "3: mov %0, %3\n" \ 233 " mov %1, #0\n" \ 234 " b 2b\n" \ 235 " .previous\n" \ 236 " .section __ex_table,\"a\"\n" \ 237 " .align 3\n" \ 238 " .long 1b, 3b\n" \ 239 " .previous" \ 240 : "+r" (err), "=&r" (x) \ 241 : "r" (addr), "i" (-EFAULT) \ 242 : "cc") 243 244#ifndef __ARMEB__ 245#define __get_user_asm_half(x,__gu_addr,err) \ 246({ \ 247 unsigned long __b1, __b2; \ 248 __get_user_asm_byte(__b1, __gu_addr, err); \ 249 __get_user_asm_byte(__b2, __gu_addr + 1, err); \ 250 (x) = __b1 | (__b2 << 8); \ 251}) 252#else 253#define __get_user_asm_half(x,__gu_addr,err) \ 254({ \ 255 unsigned long __b1, __b2; \ 256 __get_user_asm_byte(__b1, __gu_addr, err); \ 257 __get_user_asm_byte(__b2, __gu_addr + 1, err); \ 258 (x) = (__b1 << 8) | __b2; \ 259}) 260#endif 261 262#define __get_user_asm_word(x,addr,err) \ 263 __asm__ __volatile__( \ 264 "1: ldrt %1,[%2],#0\n" \ 265 "2:\n" \ 266 " .section .fixup,\"ax\"\n" \ 267 " .align 2\n" \ 268 "3: mov %0, %3\n" \ 269 " mov %1, #0\n" \ 270 " b 2b\n" \ 271 " .previous\n" \ 272 " .section __ex_table,\"a\"\n" \ 273 " .align 3\n" \ 274 " .long 1b, 3b\n" \ 275 " .previous" \ 276 : "+r" (err), "=&r" (x) \ 277 : "r" (addr), "i" (-EFAULT) \ 278 : "cc") 279 280#define __put_user(x,ptr) \ 281({ \ 282 long __pu_err = 0; \ 283 __put_user_err((x),(ptr),__pu_err); \ 284 __pu_err; \ 285}) 286 287#define __put_user_error(x,ptr,err) \ 288({ \ 289 __put_user_err((x),(ptr),err); \ 290 (void) 0; \ 291}) 292 293#define __put_user_err(x,ptr,err) \ 294do { \ 295 unsigned long __pu_addr = (unsigned long)(ptr); \ 296 __typeof__(*(ptr)) __pu_val = (x); \ 297 __chk_user_ptr(ptr); \ 298 switch (sizeof(*(ptr))) { \ 299 case 1: __put_user_asm_byte(__pu_val,__pu_addr,err); break; \ 300 case 2: __put_user_asm_half(__pu_val,__pu_addr,err); break; \ 301 case 4: __put_user_asm_word(__pu_val,__pu_addr,err); break; \ 302 case 8: __put_user_asm_dword(__pu_val,__pu_addr,err); break; \ 303 default: __put_user_bad(); \ 304 } \ 305} while (0) 306 307#define __put_user_asm_byte(x,__pu_addr,err) \ 308 __asm__ __volatile__( \ 309 "1: strbt %1,[%2],#0\n" \ 310 "2:\n" \ 311 " .section .fixup,\"ax\"\n" \ 312 " .align 2\n" \ 313 "3: mov %0, %3\n" \ 314 " b 2b\n" \ 315 " .previous\n" \ 316 " .section __ex_table,\"a\"\n" \ 317 " .align 3\n" \ 318 " .long 1b, 3b\n" \ 319 " .previous" \ 320 : "+r" (err) \ 321 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \ 322 : "cc") 323 324#ifndef __ARMEB__ 325#define __put_user_asm_half(x,__pu_addr,err) \ 326({ \ 327 unsigned long __temp = (unsigned long)(x); \ 328 __put_user_asm_byte(__temp, __pu_addr, err); \ 329 __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \ 330}) 331#else 332#define __put_user_asm_half(x,__pu_addr,err) \ 333({ \ 334 unsigned long __temp = (unsigned long)(x); \ 335 __put_user_asm_byte(__temp >> 8, __pu_addr, err); \ 336 __put_user_asm_byte(__temp, __pu_addr + 1, err); \ 337}) 338#endif 339 340#define __put_user_asm_word(x,__pu_addr,err) \ 341 __asm__ __volatile__( \ 342 "1: strt %1,[%2],#0\n" \ 343 "2:\n" \ 344 " .section .fixup,\"ax\"\n" \ 345 " .align 2\n" \ 346 "3: mov %0, %3\n" \ 347 " b 2b\n" \ 348 " .previous\n" \ 349 " .section __ex_table,\"a\"\n" \ 350 " .align 3\n" \ 351 " .long 1b, 3b\n" \ 352 " .previous" \ 353 : "+r" (err) \ 354 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \ 355 : "cc") 356 357#ifndef __ARMEB__ 358#define __reg_oper0 "%R2" 359#define __reg_oper1 "%Q2" 360#else 361#define __reg_oper0 "%Q2" 362#define __reg_oper1 "%R2" 363#endif 364 365#define __put_user_asm_dword(x,__pu_addr,err) \ 366 __asm__ __volatile__( \ 367 "1: strt " __reg_oper1 ", [%1], #4\n" \ 368 "2: strt " __reg_oper0 ", [%1], #0\n" \ 369 "3:\n" \ 370 " .section .fixup,\"ax\"\n" \ 371 " .align 2\n" \ 372 "4: mov %0, %3\n" \ 373 " b 3b\n" \ 374 " .previous\n" \ 375 " .section __ex_table,\"a\"\n" \ 376 " .align 3\n" \ 377 " .long 1b, 4b\n" \ 378 " .long 2b, 4b\n" \ 379 " .previous" \ 380 : "+r" (err), "+r" (__pu_addr) \ 381 : "r" (x), "i" (-EFAULT) \ 382 : "cc") 383 384 385#ifdef CONFIG_MMU 386extern unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n); 387extern unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n); 388extern unsigned long __clear_user(void __user *addr, unsigned long n); 389#else 390#define __copy_from_user(to,from,n) (memcpy(to, (void __force *)from, n), 0) 391#define __copy_to_user(to,from,n) (memcpy((void __force *)to, from, n), 0) 392#define __clear_user(addr,n) (memset((void __force *)addr, 0, n), 0) 393#endif 394 395extern unsigned long __strncpy_from_user(char *to, const char __user *from, unsigned long count); 396extern unsigned long __strnlen_user(const char __user *s, long n); 397 398static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n) 399{ 400 if (access_ok(VERIFY_READ, from, n)) 401 n = __copy_from_user(to, from, n); 402 else /* security hole - plug it */ 403 memzero(to, n); 404 return n; 405} 406 407static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n) 408{ 409 if (access_ok(VERIFY_WRITE, to, n)) 410 n = __copy_to_user(to, from, n); 411 return n; 412} 413 414#define __copy_to_user_inatomic __copy_to_user 415#define __copy_from_user_inatomic __copy_from_user 416 417static inline unsigned long clear_user(void __user *to, unsigned long n) 418{ 419 if (access_ok(VERIFY_WRITE, to, n)) 420 n = __clear_user(to, n); 421 return n; 422} 423 424static inline long strncpy_from_user(char *dst, const char __user *src, long count) 425{ 426 long res = -EFAULT; 427 if (access_ok(VERIFY_READ, src, 1)) 428 res = __strncpy_from_user(dst, src, count); 429 return res; 430} 431 432#define strlen_user(s) strnlen_user(s, ~0UL >> 1) 433 434static inline long strnlen_user(const char __user *s, long n) 435{ 436 unsigned long res = 0; 437 438 if (__addr_ok(s)) 439 res = __strnlen_user(s, n); 440 441 return res; 442} 443 444#endif /* _ASMARM_UACCESS_H */ 445