uaccess.h 9.9 KB

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  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. * User space memory access functions
  13. */
  14. #include <linux/sched.h>
  15. #include <linux/errno.h>
  16. #include <asm/ctl_reg.h>
  17. #define VERIFY_READ 0
  18. #define VERIFY_WRITE 1
  19. /*
  20. * The fs value determines whether argument validity checking should be
  21. * performed or not. If get_fs() == USER_DS, checking is performed, with
  22. * get_fs() == KERNEL_DS, checking is bypassed.
  23. *
  24. * For historical reasons, these macros are grossly misnamed.
  25. */
  26. #define MAKE_MM_SEG(a) ((mm_segment_t) { (a) })
  27. #define KERNEL_DS MAKE_MM_SEG(0)
  28. #define USER_DS MAKE_MM_SEG(1)
  29. #define get_ds() (KERNEL_DS)
  30. #define get_fs() (current->thread.mm_segment)
  31. #define set_fs(x) \
  32. ({ \
  33. unsigned long __pto; \
  34. current->thread.mm_segment = (x); \
  35. __pto = current->thread.mm_segment.ar4 ? \
  36. S390_lowcore.user_asce : S390_lowcore.kernel_asce; \
  37. __ctl_load(__pto, 7, 7); \
  38. })
  39. #define segment_eq(a,b) ((a).ar4 == (b).ar4)
  40. static inline int __range_ok(unsigned long addr, unsigned long size)
  41. {
  42. return 1;
  43. }
  44. #define __access_ok(addr, size) \
  45. ({ \
  46. __chk_user_ptr(addr); \
  47. __range_ok((unsigned long)(addr), (size)); \
  48. })
  49. #define access_ok(type, addr, size) __access_ok(addr, size)
  50. /*
  51. * The exception table consists of pairs of addresses: the first is the
  52. * address of an instruction that is allowed to fault, and the second is
  53. * the address at which the program should continue. No registers are
  54. * modified, so it is entirely up to the continuation code to figure out
  55. * what to do.
  56. *
  57. * All the routines below use bits of fixup code that are out of line
  58. * with the main instruction path. This means when everything is well,
  59. * we don't even have to jump over them. Further, they do not intrude
  60. * on our cache or tlb entries.
  61. */
  62. struct exception_table_entry
  63. {
  64. int insn, fixup;
  65. };
  66. static inline unsigned long extable_insn(const struct exception_table_entry *x)
  67. {
  68. return (unsigned long)&x->insn + x->insn;
  69. }
  70. static inline unsigned long extable_fixup(const struct exception_table_entry *x)
  71. {
  72. return (unsigned long)&x->fixup + x->fixup;
  73. }
  74. #define ARCH_HAS_SORT_EXTABLE
  75. #define ARCH_HAS_SEARCH_EXTABLE
  76. struct uaccess_ops {
  77. size_t (*copy_from_user)(size_t, const void __user *, void *);
  78. size_t (*copy_to_user)(size_t, void __user *, const void *);
  79. size_t (*copy_in_user)(size_t, void __user *, const void __user *);
  80. size_t (*clear_user)(size_t, void __user *);
  81. size_t (*strnlen_user)(size_t, const char __user *);
  82. size_t (*strncpy_from_user)(size_t, const char __user *, char *);
  83. int (*futex_atomic_op)(int op, u32 __user *, int oparg, int *old);
  84. int (*futex_atomic_cmpxchg)(u32 *, u32 __user *, u32 old, u32 new);
  85. };
  86. extern struct uaccess_ops uaccess;
  87. extern struct uaccess_ops uaccess_mvcos;
  88. extern struct uaccess_ops uaccess_pt;
  89. extern int __handle_fault(unsigned long, unsigned long, int);
  90. static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
  91. {
  92. size = uaccess.copy_to_user(size, ptr, x);
  93. return size ? -EFAULT : size;
  94. }
  95. static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
  96. {
  97. size = uaccess.copy_from_user(size, ptr, x);
  98. return size ? -EFAULT : size;
  99. }
  100. /*
  101. * These are the main single-value transfer routines. They automatically
  102. * use the right size if we just have the right pointer type.
  103. */
  104. #define __put_user(x, ptr) \
  105. ({ \
  106. __typeof__(*(ptr)) __x = (x); \
  107. int __pu_err = -EFAULT; \
  108. __chk_user_ptr(ptr); \
  109. switch (sizeof (*(ptr))) { \
  110. case 1: \
  111. case 2: \
  112. case 4: \
  113. case 8: \
  114. __pu_err = __put_user_fn(sizeof (*(ptr)), \
  115. ptr, &__x); \
  116. break; \
  117. default: \
  118. __put_user_bad(); \
  119. break; \
  120. } \
  121. __pu_err; \
  122. })
  123. #define put_user(x, ptr) \
  124. ({ \
  125. might_fault(); \
  126. __put_user(x, ptr); \
  127. })
  128. extern int __put_user_bad(void) __attribute__((noreturn));
  129. #define __get_user(x, ptr) \
  130. ({ \
  131. int __gu_err = -EFAULT; \
  132. __chk_user_ptr(ptr); \
  133. switch (sizeof(*(ptr))) { \
  134. case 1: { \
  135. unsigned char __x; \
  136. __gu_err = __get_user_fn(sizeof (*(ptr)), \
  137. ptr, &__x); \
  138. (x) = *(__force __typeof__(*(ptr)) *) &__x; \
  139. break; \
  140. }; \
  141. case 2: { \
  142. unsigned short __x; \
  143. __gu_err = __get_user_fn(sizeof (*(ptr)), \
  144. ptr, &__x); \
  145. (x) = *(__force __typeof__(*(ptr)) *) &__x; \
  146. break; \
  147. }; \
  148. case 4: { \
  149. unsigned int __x; \
  150. __gu_err = __get_user_fn(sizeof (*(ptr)), \
  151. ptr, &__x); \
  152. (x) = *(__force __typeof__(*(ptr)) *) &__x; \
  153. break; \
  154. }; \
  155. case 8: { \
  156. unsigned long long __x; \
  157. __gu_err = __get_user_fn(sizeof (*(ptr)), \
  158. ptr, &__x); \
  159. (x) = *(__force __typeof__(*(ptr)) *) &__x; \
  160. break; \
  161. }; \
  162. default: \
  163. __get_user_bad(); \
  164. break; \
  165. } \
  166. __gu_err; \
  167. })
  168. #define get_user(x, ptr) \
  169. ({ \
  170. might_fault(); \
  171. __get_user(x, ptr); \
  172. })
  173. extern int __get_user_bad(void) __attribute__((noreturn));
  174. #define __put_user_unaligned __put_user
  175. #define __get_user_unaligned __get_user
  176. /**
  177. * __copy_to_user: - Copy a block of data into user space, with less checking.
  178. * @to: Destination address, in user space.
  179. * @from: Source address, in kernel space.
  180. * @n: Number of bytes to copy.
  181. *
  182. * Context: User context only. This function may sleep.
  183. *
  184. * Copy data from kernel space to user space. Caller must check
  185. * the specified block with access_ok() before calling this function.
  186. *
  187. * Returns number of bytes that could not be copied.
  188. * On success, this will be zero.
  189. */
  190. static inline unsigned long __must_check
  191. __copy_to_user(void __user *to, const void *from, unsigned long n)
  192. {
  193. return uaccess.copy_to_user(n, to, from);
  194. }
  195. #define __copy_to_user_inatomic __copy_to_user
  196. #define __copy_from_user_inatomic __copy_from_user
  197. /**
  198. * copy_to_user: - Copy a block of data into user space.
  199. * @to: Destination address, in user space.
  200. * @from: Source address, in kernel space.
  201. * @n: Number of bytes to copy.
  202. *
  203. * Context: User context only. This function may sleep.
  204. *
  205. * Copy data from kernel space to user space.
  206. *
  207. * Returns number of bytes that could not be copied.
  208. * On success, this will be zero.
  209. */
  210. static inline unsigned long __must_check
  211. copy_to_user(void __user *to, const void *from, unsigned long n)
  212. {
  213. might_fault();
  214. return __copy_to_user(to, from, n);
  215. }
  216. /**
  217. * __copy_from_user: - Copy a block of data from user space, with less checking.
  218. * @to: Destination address, in kernel space.
  219. * @from: Source address, in user space.
  220. * @n: Number of bytes to copy.
  221. *
  222. * Context: User context only. This function may sleep.
  223. *
  224. * Copy data from user space to kernel space. Caller must check
  225. * the specified block with access_ok() before calling this function.
  226. *
  227. * Returns number of bytes that could not be copied.
  228. * On success, this will be zero.
  229. *
  230. * If some data could not be copied, this function will pad the copied
  231. * data to the requested size using zero bytes.
  232. */
  233. static inline unsigned long __must_check
  234. __copy_from_user(void *to, const void __user *from, unsigned long n)
  235. {
  236. return uaccess.copy_from_user(n, from, to);
  237. }
  238. extern void copy_from_user_overflow(void)
  239. #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
  240. __compiletime_warning("copy_from_user() buffer size is not provably correct")
  241. #endif
  242. ;
  243. /**
  244. * copy_from_user: - Copy a block of data from user space.
  245. * @to: Destination address, in kernel space.
  246. * @from: Source address, in user space.
  247. * @n: Number of bytes to copy.
  248. *
  249. * Context: User context only. This function may sleep.
  250. *
  251. * Copy data from user space to kernel space.
  252. *
  253. * Returns number of bytes that could not be copied.
  254. * On success, this will be zero.
  255. *
  256. * If some data could not be copied, this function will pad the copied
  257. * data to the requested size using zero bytes.
  258. */
  259. static inline unsigned long __must_check
  260. copy_from_user(void *to, const void __user *from, unsigned long n)
  261. {
  262. unsigned int sz = __compiletime_object_size(to);
  263. might_fault();
  264. if (unlikely(sz != -1 && sz < n)) {
  265. copy_from_user_overflow();
  266. return n;
  267. }
  268. return __copy_from_user(to, from, n);
  269. }
  270. static inline unsigned long __must_check
  271. __copy_in_user(void __user *to, const void __user *from, unsigned long n)
  272. {
  273. return uaccess.copy_in_user(n, to, from);
  274. }
  275. static inline unsigned long __must_check
  276. copy_in_user(void __user *to, const void __user *from, unsigned long n)
  277. {
  278. might_fault();
  279. return __copy_in_user(to, from, n);
  280. }
  281. /*
  282. * Copy a null terminated string from userspace.
  283. */
  284. static inline long __must_check
  285. strncpy_from_user(char *dst, const char __user *src, long count)
  286. {
  287. might_fault();
  288. return uaccess.strncpy_from_user(count, src, dst);
  289. }
  290. static inline unsigned long
  291. strnlen_user(const char __user * src, unsigned long n)
  292. {
  293. might_fault();
  294. return uaccess.strnlen_user(n, src);
  295. }
  296. /**
  297. * strlen_user: - Get the size of a string in user space.
  298. * @str: The string to measure.
  299. *
  300. * Context: User context only. This function may sleep.
  301. *
  302. * Get the size of a NUL-terminated string in user space.
  303. *
  304. * Returns the size of the string INCLUDING the terminating NUL.
  305. * On exception, returns 0.
  306. *
  307. * If there is a limit on the length of a valid string, you may wish to
  308. * consider using strnlen_user() instead.
  309. */
  310. #define strlen_user(str) strnlen_user(str, ~0UL)
  311. /*
  312. * Zero Userspace
  313. */
  314. static inline unsigned long __must_check
  315. __clear_user(void __user *to, unsigned long n)
  316. {
  317. return uaccess.clear_user(n, to);
  318. }
  319. static inline unsigned long __must_check
  320. clear_user(void __user *to, unsigned long n)
  321. {
  322. might_fault();
  323. return uaccess.clear_user(n, to);
  324. }
  325. extern int copy_to_user_real(void __user *dest, void *src, size_t count);
  326. extern int copy_from_user_real(void *dest, void __user *src, size_t count);
  327. #endif /* __S390_UACCESS_H */