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_fixup(const struct exception_table_entry *x) 83 { 84 return (unsigned long)&x->fixup + x->fixup; 85 } 86 87 #define ARCH_HAS_RELATIVE_EXTABLE 88 89 /** 90 * __copy_from_user: - Copy a block of data from user space, with less checking. 91 * @to: Destination address, in kernel space. 92 * @from: Source address, in user space. 93 * @n: Number of bytes to copy. 94 * 95 * Context: User context only. This function may sleep if pagefaults are 96 * enabled. 97 * 98 * Copy data from user space to kernel space. Caller must check 99 * the specified block with access_ok() before calling this function. 100 * 101 * Returns number of bytes that could not be copied. 102 * On success, this will be zero. 103 * 104 * If some data could not be copied, this function will pad the copied 105 * data to the requested size using zero bytes. 106 */ 107 unsigned long __must_check __copy_from_user(void *to, const void __user *from, 108 unsigned long n); 109 110 /** 111 * __copy_to_user: - Copy a block of data into user space, with less checking. 112 * @to: Destination address, in user space. 113 * @from: Source address, in kernel space. 114 * @n: Number of bytes to copy. 115 * 116 * Context: User context only. This function may sleep if pagefaults are 117 * enabled. 118 * 119 * Copy data from kernel space to user space. Caller must check 120 * the specified block with access_ok() before calling this function. 121 * 122 * Returns number of bytes that could not be copied. 123 * On success, this will be zero. 124 */ 125 unsigned long __must_check __copy_to_user(void __user *to, const void *from, 126 unsigned long n); 127 128 #define __copy_to_user_inatomic __copy_to_user 129 #define __copy_from_user_inatomic __copy_from_user 130 131 #ifdef CONFIG_HAVE_MARCH_Z10_FEATURES 132 133 #define __put_get_user_asm(to, from, size, spec) \ 134 ({ \ 135 register unsigned long __reg0 asm("0") = spec; \ 136 int __rc; \ 137 \ 138 asm volatile( \ 139 "0: mvcos %1,%3,%2\n" \ 140 "1: xr %0,%0\n" \ 141 "2:\n" \ 142 ".pushsection .fixup, \"ax\"\n" \ 143 "3: lhi %0,%5\n" \ 144 " jg 2b\n" \ 145 ".popsection\n" \ 146 EX_TABLE(0b,3b) EX_TABLE(1b,3b) \ 147 : "=d" (__rc), "=Q" (*(to)) \ 148 : "d" (size), "Q" (*(from)), \ 149 "d" (__reg0), "K" (-EFAULT) \ 150 : "cc"); \ 151 __rc; \ 152 }) 153 154 #define __put_user_fn(x, ptr, size) __put_get_user_asm(ptr, x, size, 0x810000UL) 155 #define __get_user_fn(x, ptr, size) __put_get_user_asm(x, ptr, size, 0x81UL) 156 157 #else /* CONFIG_HAVE_MARCH_Z10_FEATURES */ 158 159 static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size) 160 { 161 size = __copy_to_user(ptr, x, size); 162 return size ? -EFAULT : 0; 163 } 164 165 static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size) 166 { 167 size = __copy_from_user(x, ptr, size); 168 return size ? -EFAULT : 0; 169 } 170 171 #endif /* CONFIG_HAVE_MARCH_Z10_FEATURES */ 172 173 /* 174 * These are the main single-value transfer routines. They automatically 175 * use the right size if we just have the right pointer type. 176 */ 177 #define __put_user(x, ptr) \ 178 ({ \ 179 __typeof__(*(ptr)) __x = (x); \ 180 int __pu_err = -EFAULT; \ 181 __chk_user_ptr(ptr); \ 182 switch (sizeof (*(ptr))) { \ 183 case 1: \ 184 case 2: \ 185 case 4: \ 186 case 8: \ 187 __pu_err = __put_user_fn(&__x, ptr, \ 188 sizeof(*(ptr))); \ 189 break; \ 190 default: \ 191 __put_user_bad(); \ 192 break; \ 193 } \ 194 __pu_err; \ 195 }) 196 197 #define put_user(x, ptr) \ 198 ({ \ 199 might_fault(); \ 200 __put_user(x, ptr); \ 201 }) 202 203 204 int __put_user_bad(void) __attribute__((noreturn)); 205 206 #define __get_user(x, ptr) \ 207 ({ \ 208 int __gu_err = -EFAULT; \ 209 __chk_user_ptr(ptr); \ 210 switch (sizeof(*(ptr))) { \ 211 case 1: { \ 212 unsigned char __x; \ 213 __gu_err = __get_user_fn(&__x, ptr, \ 214 sizeof(*(ptr))); \ 215 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 216 break; \ 217 }; \ 218 case 2: { \ 219 unsigned short __x; \ 220 __gu_err = __get_user_fn(&__x, ptr, \ 221 sizeof(*(ptr))); \ 222 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 223 break; \ 224 }; \ 225 case 4: { \ 226 unsigned int __x; \ 227 __gu_err = __get_user_fn(&__x, ptr, \ 228 sizeof(*(ptr))); \ 229 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 230 break; \ 231 }; \ 232 case 8: { \ 233 unsigned long long __x; \ 234 __gu_err = __get_user_fn(&__x, ptr, \ 235 sizeof(*(ptr))); \ 236 (x) = *(__force __typeof__(*(ptr)) *) &__x; \ 237 break; \ 238 }; \ 239 default: \ 240 __get_user_bad(); \ 241 break; \ 242 } \ 243 __gu_err; \ 244 }) 245 246 #define get_user(x, ptr) \ 247 ({ \ 248 might_fault(); \ 249 __get_user(x, ptr); \ 250 }) 251 252 int __get_user_bad(void) __attribute__((noreturn)); 253 254 #define __put_user_unaligned __put_user 255 #define __get_user_unaligned __get_user 256 257 /** 258 * copy_to_user: - Copy a block of data into user space. 259 * @to: Destination address, in user space. 260 * @from: Source address, in kernel space. 261 * @n: Number of bytes to copy. 262 * 263 * Context: User context only. This function may sleep if pagefaults are 264 * enabled. 265 * 266 * Copy data from kernel space to user space. 267 * 268 * Returns number of bytes that could not be copied. 269 * On success, this will be zero. 270 */ 271 static inline unsigned long __must_check 272 copy_to_user(void __user *to, const void *from, unsigned long n) 273 { 274 might_fault(); 275 return __copy_to_user(to, from, n); 276 } 277 278 void copy_from_user_overflow(void) 279 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS 280 __compiletime_warning("copy_from_user() buffer size is not provably correct") 281 #endif 282 ; 283 284 /** 285 * copy_from_user: - Copy a block of data from user space. 286 * @to: Destination address, in kernel space. 287 * @from: Source address, in user space. 288 * @n: Number of bytes to copy. 289 * 290 * Context: User context only. This function may sleep if pagefaults are 291 * enabled. 292 * 293 * Copy data from user space to kernel space. 294 * 295 * Returns number of bytes that could not be copied. 296 * On success, this will be zero. 297 * 298 * If some data could not be copied, this function will pad the copied 299 * data to the requested size using zero bytes. 300 */ 301 static inline unsigned long __must_check 302 copy_from_user(void *to, const void __user *from, unsigned long n) 303 { 304 unsigned int sz = __compiletime_object_size(to); 305 306 might_fault(); 307 if (unlikely(sz != -1 && sz < n)) { 308 copy_from_user_overflow(); 309 return n; 310 } 311 return __copy_from_user(to, from, n); 312 } 313 314 unsigned long __must_check 315 __copy_in_user(void __user *to, const void __user *from, unsigned long n); 316 317 static inline unsigned long __must_check 318 copy_in_user(void __user *to, const void __user *from, unsigned long n) 319 { 320 might_fault(); 321 return __copy_in_user(to, from, n); 322 } 323 324 /* 325 * Copy a null terminated string from userspace. 326 */ 327 328 long __strncpy_from_user(char *dst, const char __user *src, long count); 329 330 static inline long __must_check 331 strncpy_from_user(char *dst, const char __user *src, long count) 332 { 333 might_fault(); 334 return __strncpy_from_user(dst, src, count); 335 } 336 337 unsigned long __must_check __strnlen_user(const char __user *src, unsigned long count); 338 339 static inline unsigned long strnlen_user(const char __user *src, unsigned long n) 340 { 341 might_fault(); 342 return __strnlen_user(src, n); 343 } 344 345 /** 346 * strlen_user: - Get the size of a string in user space. 347 * @str: The string to measure. 348 * 349 * Context: User context only. This function may sleep if pagefaults are 350 * enabled. 351 * 352 * Get the size of a NUL-terminated string in user space. 353 * 354 * Returns the size of the string INCLUDING the terminating NUL. 355 * On exception, returns 0. 356 * 357 * If there is a limit on the length of a valid string, you may wish to 358 * consider using strnlen_user() instead. 359 */ 360 #define strlen_user(str) strnlen_user(str, ~0UL) 361 362 /* 363 * Zero Userspace 364 */ 365 unsigned long __must_check __clear_user(void __user *to, unsigned long size); 366 367 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n) 368 { 369 might_fault(); 370 return __clear_user(to, n); 371 } 372 373 int copy_to_user_real(void __user *dest, void *src, unsigned long count); 374 void s390_kernel_write(void *dst, const void *src, size_t size); 375 376 #endif /* __S390_UACCESS_H */ 377