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