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+/*
+ * 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;
+extern struct uaccess_ops uaccess_mvcos_switch;
+extern struct uaccess_ops uaccess_pt;
+
+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 __must_check
+__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 __must_check
+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 __must_check
+__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 __must_check
+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 __must_check
+__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 __must_check
+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 __must_check
+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 __must_check
+__clear_user(void __user *to, unsigned long n)
+{
+ return uaccess.clear_user(n, to);
+}
+
+static inline unsigned long __must_check
+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 */
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