/* * include/asm-s390/uaccess.h * * S390 version * Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation * Author(s): Hartmut Penner (hp@de.ibm.com), * Martin Schwidefsky (schwidefsky@de.ibm.com) * * Derived from "include/asm-i386/uaccess.h" */ #ifndef __S390_UACCESS_H #define __S390_UACCESS_H /* * User space memory access functions */ #include <linux/sched.h> #include <linux/errno.h> #define VERIFY_READ 0 #define VERIFY_WRITE 1 /* * The fs value determines whether argument validity checking should be * performed or not. If get_fs() == USER_DS, checking is performed, with * get_fs() == KERNEL_DS, checking is bypassed. * * For historical reasons, these macros are grossly misnamed. */ #define MAKE_MM_SEG(a) ((mm_segment_t) { (a) }) #define KERNEL_DS MAKE_MM_SEG(0) #define USER_DS MAKE_MM_SEG(1) #define get_ds() (KERNEL_DS) #define get_fs() (current->thread.mm_segment) #define set_fs(x) \ ({ \ unsigned long __pto; \ current->thread.mm_segment = (x); \ __pto = current->thread.mm_segment.ar4 ? \ S390_lowcore.user_asce : S390_lowcore.kernel_asce; \ __ctl_load(__pto, 7, 7); \ }) #define segment_eq(a,b) ((a).ar4 == (b).ar4) static inline int __access_ok(const void __user *addr, unsigned long size) { return 1; } #define access_ok(type,addr,size) __access_ok(addr,size) /* * The exception table consists of pairs of addresses: the first is the * address of an instruction that is allowed to fault, and the second is * the address at which the program should continue. No registers are * modified, so it is entirely up to the continuation code to figure out * what to do. * * All the routines below use bits of fixup code that are out of line * with the main instruction path. This means when everything is well, * we don't even have to jump over them. Further, they do not intrude * on our cache or tlb entries. */ struct exception_table_entry { unsigned long insn, fixup; }; struct uaccess_ops { size_t (*copy_from_user)(size_t, const void __user *, void *); size_t (*copy_from_user_small)(size_t, const void __user *, void *); size_t (*copy_to_user)(size_t, void __user *, const void *); size_t (*copy_to_user_small)(size_t, void __user *, const void *); size_t (*copy_in_user)(size_t, void __user *, const void __user *); size_t (*clear_user)(size_t, void __user *); size_t (*strnlen_user)(size_t, const char __user *); size_t (*strncpy_from_user)(size_t, const char __user *, char *); int (*futex_atomic_op)(int op, int __user *, int oparg, int *old); int (*futex_atomic_cmpxchg)(int __user *, int old, int new); }; extern struct uaccess_ops uaccess; extern struct uaccess_ops uaccess_std; extern struct uaccess_ops uaccess_mvcos; static inline int __put_user_fn(size_t size, void __user *ptr, void *x) { size = uaccess.copy_to_user_small(size, ptr, x); return size ? -EFAULT : size; } static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) { size = uaccess.copy_from_user_small(size, ptr, x); return size ? -EFAULT : size; } /* * These are the main single-value transfer routines. They automatically * use the right size if we just have the right pointer type. */ #define __put_user(x, ptr) \ ({ \ __typeof__(*(ptr)) __x = (x); \ int __pu_err = -EFAULT; \ __chk_user_ptr(ptr); \ switch (sizeof (*(ptr))) { \ case 1: \ case 2: \ case 4: \ case 8: \ __pu_err = __put_user_fn(sizeof (*(ptr)), \ ptr, &__x); \ break; \ default: \ __put_user_bad(); \ break; \ } \ __pu_err; \ }) #define put_user(x, ptr) \ ({ \ might_sleep(); \ __put_user(x, ptr); \ }) extern int __put_user_bad(void) __attribute__((noreturn)); #define __get_user(x, ptr) \ ({ \ int __gu_err = -EFAULT; \ __chk_user_ptr(ptr); \ switch (sizeof(*(ptr))) { \ case 1: { \ unsigned char __x; \ __gu_err = __get_user_fn(sizeof (*(ptr)), \ ptr, &__x); \ (x) = *(__force __typeof__(*(ptr)) *) &__x; \ break; \ }; \ case 2: { \ unsigned short __x; \ __gu_err = __get_user_fn(sizeof (*(ptr)), \ ptr, &__x); \ (x) = *(__force __typeof__(*(ptr)) *) &__x; \ break; \ }; \ case 4: { \ unsigned int __x; \ __gu_err = __get_user_fn(sizeof (*(ptr)), \ ptr, &__x); \ (x) = *(__force __typeof__(*(ptr)) *) &__x; \ break; \ }; \ case 8: { \ unsigned long long __x; \ __gu_err = __get_user_fn(sizeof (*(ptr)), \ ptr, &__x); \ (x) = *(__force __typeof__(*(ptr)) *) &__x; \ break; \ }; \ default: \ __get_user_bad(); \ break; \ } \ __gu_err; \ }) #define get_user(x, ptr) \ ({ \ might_sleep(); \ __get_user(x, ptr); \ }) extern int __get_user_bad(void) __attribute__((noreturn)); #define __put_user_unaligned __put_user #define __get_user_unaligned __get_user /** * __copy_to_user: - Copy a block of data into user space, with less checking. * @to: Destination address, in user space. * @from: Source address, in kernel space. * @n: Number of bytes to copy. * * Context: User context only. This function may sleep. * * Copy data from kernel space to user space. Caller must check * the specified block with access_ok() before calling this function. * * Returns number of bytes that could not be copied. * On success, this will be zero. */ static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n) { if (__builtin_constant_p(n) && (n <= 256)) return uaccess.copy_to_user_small(n, to, from); else return uaccess.copy_to_user(n, to, from); } #define __copy_to_user_inatomic __copy_to_user #define __copy_from_user_inatomic __copy_from_user /** * copy_to_user: - Copy a block of data into user space. * @to: Destination address, in user space. * @from: Source address, in kernel space. * @n: Number of bytes to copy. * * Context: User context only. This function may sleep. * * Copy data from kernel space to user space. * * Returns number of bytes that could not be copied. * On success, this will be zero. */ static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n) { might_sleep(); if (access_ok(VERIFY_WRITE, to, n)) n = __copy_to_user(to, from, n); return n; } /** * __copy_from_user: - Copy a block of data from user space, with less checking. * @to: Destination address, in kernel space. * @from: Source address, in user space. * @n: Number of bytes to copy. * * Context: User context only. This function may sleep. * * Copy data from user space to kernel space. Caller must check * the specified block with access_ok() before calling this function. * * Returns number of bytes that could not be copied. * On success, this will be zero. * * If some data could not be copied, this function will pad the copied * data to the requested size using zero bytes. */ static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n) { if (__builtin_constant_p(n) && (n <= 256)) return uaccess.copy_from_user_small(n, from, to); else return uaccess.copy_from_user(n, from, to); } /** * copy_from_user: - Copy a block of data from user space. * @to: Destination address, in kernel space. * @from: Source address, in user space. * @n: Number of bytes to copy. * * Context: User context only. This function may sleep. * * Copy data from user space to kernel space. * * Returns number of bytes that could not be copied. * On success, this will be zero. * * If some data could not be copied, this function will pad the copied * data to the requested size using zero bytes. */ static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n) { might_sleep(); if (access_ok(VERIFY_READ, from, n)) n = __copy_from_user(to, from, n); else memset(to, 0, n); return n; } static inline unsigned long __copy_in_user(void __user *to, const void __user *from, unsigned long n) { return uaccess.copy_in_user(n, to, from); } static inline unsigned long copy_in_user(void __user *to, const void __user *from, unsigned long n) { might_sleep(); if (__access_ok(from,n) && __access_ok(to,n)) n = __copy_in_user(to, from, n); return n; } /* * Copy a null terminated string from userspace. */ static inline long strncpy_from_user(char *dst, const char __user *src, long count) { long res = -EFAULT; might_sleep(); if (access_ok(VERIFY_READ, src, 1)) res = uaccess.strncpy_from_user(count, src, dst); return res; } static inline unsigned long strnlen_user(const char __user * src, unsigned long n) { might_sleep(); return uaccess.strnlen_user(n, src); } /** * strlen_user: - Get the size of a string in user space. * @str: The string to measure. * * Context: User context only. This function may sleep. * * Get the size of a NUL-terminated string in user space. * * Returns the size of the string INCLUDING the terminating NUL. * On exception, returns 0. * * If there is a limit on the length of a valid string, you may wish to * consider using strnlen_user() instead. */ #define strlen_user(str) strnlen_user(str, ~0UL) /* * Zero Userspace */ static inline unsigned long __clear_user(void __user *to, unsigned long n) { return uaccess.clear_user(n, to); } static inline unsigned long clear_user(void __user *to, unsigned long n) { might_sleep(); if (access_ok(VERIFY_WRITE, to, n)) n = uaccess.clear_user(n, to); return n; } #endif /* __S390_UACCESS_H */