1 #ifndef _ASM_IA64_UACCESS_H 2 #define _ASM_IA64_UACCESS_H 3 4 /* 5 * This file defines various macros to transfer memory areas across 6 * the user/kernel boundary. This needs to be done carefully because 7 * this code is executed in kernel mode and uses user-specified 8 * addresses. Thus, we need to be careful not to let the user to 9 * trick us into accessing kernel memory that would normally be 10 * inaccessible. This code is also fairly performance sensitive, 11 * so we want to spend as little time doing safety checks as 12 * possible. 13 * 14 * To make matters a bit more interesting, these macros sometimes also 15 * called from within the kernel itself, in which case the address 16 * validity check must be skipped. The get_fs() macro tells us what 17 * to do: if get_fs()==USER_DS, checking is performed, if 18 * get_fs()==KERNEL_DS, checking is bypassed. 19 * 20 * Note that even if the memory area specified by the user is in a 21 * valid address range, it is still possible that we'll get a page 22 * fault while accessing it. This is handled by filling out an 23 * exception handler fixup entry for each instruction that has the 24 * potential to fault. When such a fault occurs, the page fault 25 * handler checks to see whether the faulting instruction has a fixup 26 * associated and, if so, sets r8 to -EFAULT and clears r9 to 0 and 27 * then resumes execution at the continuation point. 28 * 29 * Based on <asm-alpha/uaccess.h>. 30 * 31 * Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co 32 * David Mosberger-Tang <davidm@hpl.hp.com> 33 */ 34 35 #include <linux/compiler.h> 36 #include <linux/errno.h> 37 #include <linux/sched.h> 38 #include <linux/page-flags.h> 39 #include <linux/mm.h> 40 41 #include <asm/intrinsics.h> 42 #include <asm/pgtable.h> 43 #include <asm/io.h> 44 45 /* 46 * For historical reasons, the following macros are grossly misnamed: 47 */ 48 #define KERNEL_DS ((mm_segment_t) { ~0UL }) /* cf. access_ok() */ 49 #define USER_DS ((mm_segment_t) { TASK_SIZE-1 }) /* cf. access_ok() */ 50 51 #define VERIFY_READ 0 52 #define VERIFY_WRITE 1 53 54 #define get_ds() (KERNEL_DS) 55 #define get_fs() (current_thread_info()->addr_limit) 56 #define set_fs(x) (current_thread_info()->addr_limit = (x)) 57 58 #define segment_eq(a, b) ((a).seg == (b).seg) 59 60 /* 61 * When accessing user memory, we need to make sure the entire area really is in 62 * user-level space. In order to do this efficiently, we make sure that the page at 63 * address TASK_SIZE is never valid. We also need to make sure that the address doesn't 64 * point inside the virtually mapped linear page table. 65 */ 66 #define __access_ok(addr, size, segment) \ 67 ({ \ 68 __chk_user_ptr(addr); \ 69 (likely((unsigned long) (addr) <= (segment).seg) \ 70 && ((segment).seg == KERNEL_DS.seg \ 71 || likely(REGION_OFFSET((unsigned long) (addr)) < RGN_MAP_LIMIT))); \ 72 }) 73 #define access_ok(type, addr, size) __access_ok((addr), (size), get_fs()) 74 75 /* 76 * These are the main single-value transfer routines. They automatically 77 * use the right size if we just have the right pointer type. 78 * 79 * Careful to not 80 * (a) re-use the arguments for side effects (sizeof/typeof is ok) 81 * (b) require any knowledge of processes at this stage 82 */ 83 #define put_user(x, ptr) __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)), get_fs()) 84 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)), get_fs()) 85 86 /* 87 * The "__xxx" versions do not do address space checking, useful when 88 * doing multiple accesses to the same area (the programmer has to do the 89 * checks by hand with "access_ok()") 90 */ 91 #define __put_user(x, ptr) __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr))) 92 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr))) 93 94 extern long __put_user_unaligned_unknown (void); 95 96 #define __put_user_unaligned(x, ptr) \ 97 ({ \ 98 long __ret; \ 99 switch (sizeof(*(ptr))) { \ 100 case 1: __ret = __put_user((x), (ptr)); break; \ 101 case 2: __ret = (__put_user((x), (u8 __user *)(ptr))) \ 102 | (__put_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break; \ 103 case 4: __ret = (__put_user((x), (u16 __user *)(ptr))) \ 104 | (__put_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break; \ 105 case 8: __ret = (__put_user((x), (u32 __user *)(ptr))) \ 106 | (__put_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break; \ 107 default: __ret = __put_user_unaligned_unknown(); \ 108 } \ 109 __ret; \ 110 }) 111 112 extern long __get_user_unaligned_unknown (void); 113 114 #define __get_user_unaligned(x, ptr) \ 115 ({ \ 116 long __ret; \ 117 switch (sizeof(*(ptr))) { \ 118 case 1: __ret = __get_user((x), (ptr)); break; \ 119 case 2: __ret = (__get_user((x), (u8 __user *)(ptr))) \ 120 | (__get_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break; \ 121 case 4: __ret = (__get_user((x), (u16 __user *)(ptr))) \ 122 | (__get_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break; \ 123 case 8: __ret = (__get_user((x), (u32 __user *)(ptr))) \ 124 | (__get_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break; \ 125 default: __ret = __get_user_unaligned_unknown(); \ 126 } \ 127 __ret; \ 128 }) 129 130 #ifdef ASM_SUPPORTED 131 struct __large_struct { unsigned long buf[100]; }; 132 # define __m(x) (*(struct __large_struct __user *)(x)) 133 134 /* We need to declare the __ex_table section before we can use it in .xdata. */ 135 asm (".section \"__ex_table\", \"a\"\n\t.previous"); 136 137 # define __get_user_size(val, addr, n, err) \ 138 do { \ 139 register long __gu_r8 asm ("r8") = 0; \ 140 register long __gu_r9 asm ("r9"); \ 141 asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n" \ 142 "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n" \ 143 "[1:]" \ 144 : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8)); \ 145 (err) = __gu_r8; \ 146 (val) = __gu_r9; \ 147 } while (0) 148 149 /* 150 * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it. This 151 * is because they do not write to any memory gcc knows about, so there are no aliasing 152 * issues. 153 */ 154 # define __put_user_size(val, addr, n, err) \ 155 do { \ 156 register long __pu_r8 asm ("r8") = 0; \ 157 asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \ 158 "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n" \ 159 "[1:]" \ 160 : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8)); \ 161 (err) = __pu_r8; \ 162 } while (0) 163 164 #else /* !ASM_SUPPORTED */ 165 # define RELOC_TYPE 2 /* ip-rel */ 166 # define __get_user_size(val, addr, n, err) \ 167 do { \ 168 __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE); \ 169 (err) = ia64_getreg(_IA64_REG_R8); \ 170 (val) = ia64_getreg(_IA64_REG_R9); \ 171 } while (0) 172 # define __put_user_size(val, addr, n, err) \ 173 do { \ 174 __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, \ 175 (__force unsigned long) (val)); \ 176 (err) = ia64_getreg(_IA64_REG_R8); \ 177 } while (0) 178 #endif /* !ASM_SUPPORTED */ 179 180 extern void __get_user_unknown (void); 181 182 /* 183 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which 184 * could clobber r8 and r9 (among others). Thus, be careful not to evaluate it while 185 * using r8/r9. 186 */ 187 #define __do_get_user(check, x, ptr, size, segment) \ 188 ({ \ 189 const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ 190 __typeof__ (size) __gu_size = (size); \ 191 long __gu_err = -EFAULT; \ 192 unsigned long __gu_val = 0; \ 193 if (!check || __access_ok(__gu_ptr, size, segment)) \ 194 switch (__gu_size) { \ 195 case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break; \ 196 case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break; \ 197 case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break; \ 198 case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break; \ 199 default: __get_user_unknown(); break; \ 200 } \ 201 (x) = (__force __typeof__(*(__gu_ptr))) __gu_val; \ 202 __gu_err; \ 203 }) 204 205 #define __get_user_nocheck(x, ptr, size) __do_get_user(0, x, ptr, size, KERNEL_DS) 206 #define __get_user_check(x, ptr, size, segment) __do_get_user(1, x, ptr, size, segment) 207 208 extern void __put_user_unknown (void); 209 210 /* 211 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which 212 * could clobber r8 (among others). Thus, be careful not to evaluate them while using r8. 213 */ 214 #define __do_put_user(check, x, ptr, size, segment) \ 215 ({ \ 216 __typeof__ (x) __pu_x = (x); \ 217 __typeof__ (*(ptr)) __user *__pu_ptr = (ptr); \ 218 __typeof__ (size) __pu_size = (size); \ 219 long __pu_err = -EFAULT; \ 220 \ 221 if (!check || __access_ok(__pu_ptr, __pu_size, segment)) \ 222 switch (__pu_size) { \ 223 case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break; \ 224 case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break; \ 225 case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break; \ 226 case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break; \ 227 default: __put_user_unknown(); break; \ 228 } \ 229 __pu_err; \ 230 }) 231 232 #define __put_user_nocheck(x, ptr, size) __do_put_user(0, x, ptr, size, KERNEL_DS) 233 #define __put_user_check(x, ptr, size, segment) __do_put_user(1, x, ptr, size, segment) 234 235 /* 236 * Complex access routines 237 */ 238 extern unsigned long __must_check __copy_user (void __user *to, const void __user *from, 239 unsigned long count); 240 241 static inline unsigned long 242 __copy_to_user (void __user *to, const void *from, unsigned long count) 243 { 244 check_object_size(from, count, true); 245 246 return __copy_user(to, (__force void __user *) from, count); 247 } 248 249 static inline unsigned long 250 __copy_from_user (void *to, const void __user *from, unsigned long count) 251 { 252 check_object_size(to, count, false); 253 254 return __copy_user((__force void __user *) to, from, count); 255 } 256 257 #define __copy_to_user_inatomic __copy_to_user 258 #define __copy_from_user_inatomic __copy_from_user 259 #define copy_to_user(to, from, n) \ 260 ({ \ 261 void __user *__cu_to = (to); \ 262 const void *__cu_from = (from); \ 263 long __cu_len = (n); \ 264 \ 265 if (__access_ok(__cu_to, __cu_len, get_fs())) { \ 266 check_object_size(__cu_from, __cu_len, true); \ 267 __cu_len = __copy_user(__cu_to, (__force void __user *) __cu_from, __cu_len); \ 268 } \ 269 __cu_len; \ 270 }) 271 272 static inline unsigned long 273 copy_from_user(void *to, const void __user *from, unsigned long n) 274 { 275 check_object_size(to, n, false); 276 if (likely(__access_ok(from, n, get_fs()))) 277 n = __copy_user((__force void __user *) to, from, n); 278 else 279 memset(to, 0, n); 280 return n; 281 } 282 283 #define __copy_in_user(to, from, size) __copy_user((to), (from), (size)) 284 285 static inline unsigned long 286 copy_in_user (void __user *to, const void __user *from, unsigned long n) 287 { 288 if (likely(access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n))) 289 n = __copy_user(to, from, n); 290 return n; 291 } 292 293 extern unsigned long __do_clear_user (void __user *, unsigned long); 294 295 #define __clear_user(to, n) __do_clear_user(to, n) 296 297 #define clear_user(to, n) \ 298 ({ \ 299 unsigned long __cu_len = (n); \ 300 if (__access_ok(to, __cu_len, get_fs())) \ 301 __cu_len = __do_clear_user(to, __cu_len); \ 302 __cu_len; \ 303 }) 304 305 306 /* 307 * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else 308 * strlen. 309 */ 310 extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len); 311 312 #define strncpy_from_user(to, from, n) \ 313 ({ \ 314 const char __user * __sfu_from = (from); \ 315 long __sfu_ret = -EFAULT; \ 316 if (__access_ok(__sfu_from, 0, get_fs())) \ 317 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \ 318 __sfu_ret; \ 319 }) 320 321 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */ 322 extern unsigned long __strlen_user (const char __user *); 323 324 #define strlen_user(str) \ 325 ({ \ 326 const char __user *__su_str = (str); \ 327 unsigned long __su_ret = 0; \ 328 if (__access_ok(__su_str, 0, get_fs())) \ 329 __su_ret = __strlen_user(__su_str); \ 330 __su_ret; \ 331 }) 332 333 /* 334 * Returns: 0 if exception before NUL or reaching the supplied limit 335 * (N), a value greater than N if the limit would be exceeded, else 336 * strlen. 337 */ 338 extern unsigned long __strnlen_user (const char __user *, long); 339 340 #define strnlen_user(str, len) \ 341 ({ \ 342 const char __user *__su_str = (str); \ 343 unsigned long __su_ret = 0; \ 344 if (__access_ok(__su_str, 0, get_fs())) \ 345 __su_ret = __strnlen_user(__su_str, len); \ 346 __su_ret; \ 347 }) 348 349 #define ARCH_HAS_RELATIVE_EXTABLE 350 351 struct exception_table_entry { 352 int insn; /* location-relative address of insn this fixup is for */ 353 int fixup; /* location-relative continuation addr.; if bit 2 is set, r9 is set to 0 */ 354 }; 355 356 #define ARCH_HAS_TRANSLATE_MEM_PTR 1 357 static __inline__ void * 358 xlate_dev_mem_ptr(phys_addr_t p) 359 { 360 struct page *page; 361 void *ptr; 362 363 page = pfn_to_page(p >> PAGE_SHIFT); 364 if (PageUncached(page)) 365 ptr = (void *)p + __IA64_UNCACHED_OFFSET; 366 else 367 ptr = __va(p); 368 369 return ptr; 370 } 371 372 /* 373 * Convert a virtual cached kernel memory pointer to an uncached pointer 374 */ 375 static __inline__ void * 376 xlate_dev_kmem_ptr(void *p) 377 { 378 struct page *page; 379 void *ptr; 380 381 page = virt_to_page((unsigned long)p); 382 if (PageUncached(page)) 383 ptr = (void *)__pa(p) + __IA64_UNCACHED_OFFSET; 384 else 385 ptr = p; 386 387 return ptr; 388 } 389 390 #endif /* _ASM_IA64_UACCESS_H */ 391