1 /* 2 * S390 version 3 * Copyright IBM Corp. 1999, 2000 4 * Author(s): Hartmut Penner (hp@de.ibm.com), 5 * Martin Schwidefsky (schwidefsky@de.ibm.com) 6 * 7 * Derived from "include/asm-i386/uaccess.h" 8 */ 9 #ifndef __S390_UACCESS_H 10 #define __S390_UACCESS_H 11 12 /* 13 * User space memory access functions 14 */ 15 #include <linux/sched.h> 16 #include <linux/errno.h> 17 #include <asm/ctl_reg.h> 18 19 #define VERIFY_READ 0 20 #define VERIFY_WRITE 1 21 22 23 /* 24 * The fs value determines whether argument validity checking should be 25 * performed or not. If get_fs() == USER_DS, checking is performed, with 26 * get_fs() == KERNEL_DS, checking is bypassed. 27 * 28 * For historical reasons, these macros are grossly misnamed. 29 */ 30 31 #define MAKE_MM_SEG(a) ((mm_segment_t) { (a) }) 32 33 34 #define KERNEL_DS MAKE_MM_SEG(0) 35 #define USER_DS MAKE_MM_SEG(1) 36 37 #define get_ds() (KERNEL_DS) 38 #define get_fs() (current->thread.mm_segment) 39 40 #define set_fs(x) \ 41 ({ \ 42 unsigned long __pto; \ 43 current->thread.mm_segment = (x); \ 44 __pto = current->thread.mm_segment.ar4 ? \ 45 S390_lowcore.user_asce : S390_lowcore.kernel_asce; \ 46 __ctl_load(__pto, 7, 7); \ 47 }) 48 49 #define segment_eq(a,b) ((a).ar4 == (b).ar4) 50 51 static inline int __range_ok(unsigned long addr, unsigned long size) 52 { 53 return 1; 54 } 55 56 #define __access_ok(addr, size) \ 57 ({ \ 58 __chk_user_ptr(addr); \ 59 __range_ok((unsigned long)(addr), (size)); \ 60 }) 61 62 #define access_ok(type, addr, size) __access_ok(addr, size) 63 64 /* 65 * The exception table consists of pairs of addresses: the first is the 66 * address of an instruction that is allowed to fault, and the second is 67 * the address at which the program should continue. No registers are 68 * modified, so it is entirely up to the continuation code to figure out 69 * what to do. 70 * 71 * All the routines below use bits of fixup code that are out of line 72 * with the main instruction path. This means when everything is well, 73 * we don't even have to jump over them. Further, they do not intrude 74 * on our cache or tlb entries. 75 */ 76 77 struct exception_table_entry 78 { 79 int insn, fixup; 80 }; 81 82 static inline unsigned long extable_insn(const struct exception_table_entry *x) 83 { 84 return (unsigned long)&x->insn + x->insn; 85 } 86 87 static inline unsigned long extable_fixup(const struct exception_table_entry *x) 88 { 89 return (unsigned long)&x->fixup + x->fixup; 90 } 91 92 #define ARCH_HAS_SORT_EXTABLE 93 #define ARCH_HAS_SEARCH_EXTABLE 94 95 /** 96 * __copy_from_user: - Copy a block of data from user space, with less checking. 97 * @to: Destination address, in kernel space. 98 * @from: Source address, in user space. 99 * @n: Number of bytes to copy. 100 * 101 * Context: User context only. This function may sleep if pagefaults are 102 * enabled. 103 * 104 * Copy data from user space to kernel space. Caller must check 105 * the specified block with access_ok() before calling this function. 106 * 107 * Returns number of bytes that could not be copied. 108 * On success, this will be zero. 109 * 110 * If some data could not be copied, this function will pad the copied 111 * data to the requested size using zero bytes. 112 */ 113 unsigned long __must_check __copy_from_user(void *to, const void __user *from, 114 unsigned long n); 115 116 /** 117 * __copy_to_user: - Copy a block of data into user space, with less checking. 118 * @to: Destination address, in user space. 119 * @from: Source address, in kernel space. 120 * @n: Number of bytes to copy. 121 * 122 * Context: User context only. This function may sleep if pagefaults are 123 * enabled. 124 * 125 * Copy data from kernel space to user space. Caller must check 126 * the specified block with access_ok() before calling this function. 127 * 128 * Returns number of bytes that could not be copied. 129 * On success, this will be zero. 130 */ 131 unsigned long __must_check __copy_to_user(void __user *to, const void *from, 132 unsigned long n); 133 134 #define __copy_to_user_inatomic __copy_to_user 135 #define __copy_from_user_inatomic __copy_from_user 136 137 #ifdef CONFIG_HAVE_MARCH_Z10_FEATURES 138 139 #define __put_get_user_asm(to, from, size, spec) \ 140 ({ \ 141 register unsigned long __reg0 asm("0") = spec; \ 142 int __rc; \ 143 \ 144 asm volatile( \ 145 "0: mvcos %1,%3,%2\n" \ 146 "1: xr %0,%0\n" \ 147 "2:\n" \ 148 ".pushsection .fixup, \"ax\"\n" \ 149 "3: lhi %0,%5\n" \ 150 " jg 2b\n" \ 151 ".popsection\n" \ 152 EX_TABLE(0b,3b) EX_TABLE(1b,3b) \ 153 : "=d" (__rc), "=Q" (*(to)) \ 154 : "d" (size), "Q" (*(from)), \ 155 "d" (__reg0), "K" (-EFAULT) \ 156 : "cc"); \ 157 __rc; \ 158 }) 159 160 #define __put_user_fn(x, ptr, size) __put_get_user_asm(ptr, x, size, 0x810000UL) 161 #define __get_user_fn(x, ptr, size) __put_get_user_asm(x, ptr, size, 0x81UL) 162 163 #else /* CONFIG_HAVE_MARCH_Z10_FEATURES */ 164 165 static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size) 166 { 167 size = __copy_to_user(ptr, x, size); 168 return size ? -EFAULT : 0; 169 } 170 171 static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size) 172 { 173 size = __copy_from_user(x, ptr, size); 174 return size ? -EFAULT : 0; 175 } 176 177 #endif /* CONFIG_HAVE_MARCH_Z10_FEATURES */ 178 179 /* 180 * These are the main single-value transfer routines. They automatically 181 * use the right size if we just have the right pointer type. 182 */ 183 #define __put_user(x, ptr) \ 184 ({ \ 185 __typeof__(*(ptr)) __x = (x); \ 186 int __pu_err = -EFAULT; \ 187 __chk_user_ptr(ptr); \ 188 switch (sizeof (*(ptr))) { \ 189 case 1: \ 190 case 2: \ 191 case 4: \ 192 case 8: \ 193 __pu_err = __put_user_fn(&__x, ptr, \ 194 sizeof(*(ptr))); \ 195 break; \ 196 default: \ 197 __put_user_bad(); \ 198 break; \ 199 } \ 200 __pu_err; \ 201 }) 202 203 #define put_user(x, ptr) \ 204 ({ \ 205 might_fault(); \ 206 __put_user(x, ptr); \ 207 }) 208 209 210 int __put_user_bad(void) __attribute__((noreturn)); 211 212 #define __get_user(x, ptr) \ 213 ({ \ 214 int __gu_err = -EFAULT; \ 215 __chk_user_ptr(ptr); \ 216 switch (sizeof(*(ptr))) { \ 217 case 1: { \ 218 unsigned char __x; \ 219 __gu_err = __get_user_fn(&__x, ptr, \ 220 sizeof(*(ptr))); \ 221 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 222 break; \ 223 }; \ 224 case 2: { \ 225 unsigned short __x; \ 226 __gu_err = __get_user_fn(&__x, ptr, \ 227 sizeof(*(ptr))); \ 228 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 229 break; \ 230 }; \ 231 case 4: { \ 232 unsigned int __x; \ 233 __gu_err = __get_user_fn(&__x, ptr, \ 234 sizeof(*(ptr))); \ 235 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 236 break; \ 237 }; \ 238 case 8: { \ 239 unsigned long long __x; \ 240 __gu_err = __get_user_fn(&__x, ptr, \ 241 sizeof(*(ptr))); \ 242 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 243 break; \ 244 }; \ 245 default: \ 246 __get_user_bad(); \ 247 break; \ 248 } \ 249 __gu_err; \ 250 }) 251 252 #define get_user(x, ptr) \ 253 ({ \ 254 might_fault(); \ 255 __get_user(x, ptr); \ 256 }) 257 258 int __get_user_bad(void) __attribute__((noreturn)); 259 260 #define __put_user_unaligned __put_user 261 #define __get_user_unaligned __get_user 262 263 /** 264 * copy_to_user: - Copy a block of data into user space. 265 * @to: Destination address, in user space. 266 * @from: Source address, in kernel space. 267 * @n: Number of bytes to copy. 268 * 269 * Context: User context only. This function may sleep if pagefaults are 270 * enabled. 271 * 272 * Copy data from kernel space to user space. 273 * 274 * Returns number of bytes that could not be copied. 275 * On success, this will be zero. 276 */ 277 static inline unsigned long __must_check 278 copy_to_user(void __user *to, const void *from, unsigned long n) 279 { 280 might_fault(); 281 return __copy_to_user(to, from, n); 282 } 283 284 void copy_from_user_overflow(void) 285 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS 286 __compiletime_warning("copy_from_user() buffer size is not provably correct") 287 #endif 288 ; 289 290 /** 291 * copy_from_user: - Copy a block of data from user space. 292 * @to: Destination address, in kernel space. 293 * @from: Source address, in user space. 294 * @n: Number of bytes to copy. 295 * 296 * Context: User context only. This function may sleep if pagefaults are 297 * enabled. 298 * 299 * Copy data from user space to kernel space. 300 * 301 * Returns number of bytes that could not be copied. 302 * On success, this will be zero. 303 * 304 * If some data could not be copied, this function will pad the copied 305 * data to the requested size using zero bytes. 306 */ 307 static inline unsigned long __must_check 308 copy_from_user(void *to, const void __user *from, unsigned long n) 309 { 310 unsigned int sz = __compiletime_object_size(to); 311 312 might_fault(); 313 if (unlikely(sz != -1 && sz < n)) { 314 copy_from_user_overflow(); 315 return n; 316 } 317 return __copy_from_user(to, from, n); 318 } 319 320 unsigned long __must_check 321 __copy_in_user(void __user *to, const void __user *from, unsigned long n); 322 323 static inline unsigned long __must_check 324 copy_in_user(void __user *to, const void __user *from, unsigned long n) 325 { 326 might_fault(); 327 return __copy_in_user(to, from, n); 328 } 329 330 /* 331 * Copy a null terminated string from userspace. 332 */ 333 334 long __strncpy_from_user(char *dst, const char __user *src, long count); 335 336 static inline long __must_check 337 strncpy_from_user(char *dst, const char __user *src, long count) 338 { 339 might_fault(); 340 return __strncpy_from_user(dst, src, count); 341 } 342 343 unsigned long __must_check __strnlen_user(const char __user *src, unsigned long count); 344 345 static inline unsigned long strnlen_user(const char __user *src, unsigned long n) 346 { 347 might_fault(); 348 return __strnlen_user(src, n); 349 } 350 351 /** 352 * strlen_user: - Get the size of a string in user space. 353 * @str: The string to measure. 354 * 355 * Context: User context only. This function may sleep if pagefaults are 356 * enabled. 357 * 358 * Get the size of a NUL-terminated string in user space. 359 * 360 * Returns the size of the string INCLUDING the terminating NUL. 361 * On exception, returns 0. 362 * 363 * If there is a limit on the length of a valid string, you may wish to 364 * consider using strnlen_user() instead. 365 */ 366 #define strlen_user(str) strnlen_user(str, ~0UL) 367 368 /* 369 * Zero Userspace 370 */ 371 unsigned long __must_check __clear_user(void __user *to, unsigned long size); 372 373 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n) 374 { 375 might_fault(); 376 return __clear_user(to, n); 377 } 378 379 int copy_to_user_real(void __user *dest, void *src, unsigned long count); 380 void s390_kernel_write(void *dst, const void *src, size_t size); 381 382 #endif /* __S390_UACCESS_H */ 383