328 lines
7.2 KiB
C
328 lines
7.2 KiB
C
#ifndef __ASM_GENERIC_UACCESS_H
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#define __ASM_GENERIC_UACCESS_H
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/*
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* User space memory access functions, these should work
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* on a ny machine that has kernel and user data in the same
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* address space, e.g. all NOMMU machines.
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*/
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <asm/segment.h>
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#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
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#ifndef KERNEL_DS
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#define KERNEL_DS MAKE_MM_SEG(~0UL)
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#endif
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#ifndef USER_DS
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#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
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#endif
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#ifndef get_fs
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#define get_ds() (KERNEL_DS)
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#define get_fs() (current_thread_info()->addr_limit)
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static inline void set_fs(mm_segment_t fs)
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{
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current_thread_info()->addr_limit = fs;
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}
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#endif
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#define segment_eq(a, b) ((a).seg == (b).seg)
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#define VERIFY_READ 0
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#define VERIFY_WRITE 1
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#define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size))
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/*
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* The architecture should really override this if possible, at least
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* doing a check on the get_fs()
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*/
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#ifndef __access_ok
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static inline int __access_ok(unsigned long addr, unsigned long size)
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{
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return 1;
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}
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#endif
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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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/* Returns 0 if exception not found and fixup otherwise. */
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extern unsigned long search_exception_table(unsigned long);
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/*
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* architectures with an MMU should override these two
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*/
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#ifndef __copy_from_user
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static inline __must_check long __copy_from_user(void *to,
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const void __user * from, unsigned long n)
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{
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if (__builtin_constant_p(n)) {
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switch(n) {
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case 1:
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*(u8 *)to = *(u8 __force *)from;
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return 0;
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case 2:
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*(u16 *)to = *(u16 __force *)from;
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return 0;
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case 4:
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*(u32 *)to = *(u32 __force *)from;
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return 0;
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#ifdef CONFIG_64BIT
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case 8:
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*(u64 *)to = *(u64 __force *)from;
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return 0;
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#endif
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default:
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break;
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}
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}
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memcpy(to, (const void __force *)from, n);
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return 0;
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}
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#endif
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#ifndef __copy_to_user
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static inline __must_check long __copy_to_user(void __user *to,
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const void *from, unsigned long n)
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{
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if (__builtin_constant_p(n)) {
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switch(n) {
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case 1:
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*(u8 __force *)to = *(u8 *)from;
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return 0;
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case 2:
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*(u16 __force *)to = *(u16 *)from;
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return 0;
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case 4:
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*(u32 __force *)to = *(u32 *)from;
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return 0;
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#ifdef CONFIG_64BIT
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case 8:
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*(u64 __force *)to = *(u64 *)from;
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return 0;
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#endif
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default:
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break;
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}
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}
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memcpy((void __force *)to, from, n);
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return 0;
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}
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#endif
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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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* This version just falls back to copy_{from,to}_user, which should
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* provide a fast-path for small values.
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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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access_ok(VERIFY_WRITE, ptr, sizeof(*ptr)) ? \
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__put_user(x, ptr) : \
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-EFAULT; \
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})
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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 = __copy_to_user(ptr, x, size);
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return size ? -EFAULT : size;
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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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access_ok(VERIFY_READ, ptr, sizeof(*ptr)) ? \
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__get_user(x, ptr) : \
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-EFAULT; \
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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 = __copy_from_user(x, ptr, size);
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return size ? -EFAULT : size;
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}
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extern int __get_user_bad(void) __attribute__((noreturn));
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#ifndef __copy_from_user_inatomic
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#define __copy_from_user_inatomic __copy_from_user
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#endif
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#ifndef __copy_to_user_inatomic
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#define __copy_to_user_inatomic __copy_to_user
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#endif
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static inline long copy_from_user(void *to,
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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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return __copy_from_user(to, from, n);
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else
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return n;
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}
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static inline long copy_to_user(void __user *to,
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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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return __copy_to_user(to, from, n);
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else
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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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#ifndef __strncpy_from_user
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static inline long
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__strncpy_from_user(char *dst, const char __user *src, long count)
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{
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char *tmp;
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strncpy(dst, (const char __force *)src, count);
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for (tmp = dst; *tmp && count > 0; tmp++, count--)
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;
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return (tmp - dst);
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}
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#endif
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static inline long
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strncpy_from_user(char *dst, const char __user *src, long count)
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{
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if (!access_ok(VERIFY_READ, src, 1))
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return -EFAULT;
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return __strncpy_from_user(dst, src, count);
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}
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/*
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* Return the size of a string (including the ending 0)
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*
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* Return 0 on exception, a value greater than N if too long
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*/
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#ifndef strnlen_user
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static inline long strnlen_user(const char __user *src, long n)
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{
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if (!access_ok(VERIFY_READ, src, 1))
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return 0;
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return strlen((void * __force)src) + 1;
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}
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#endif
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static inline long strlen_user(const char __user *src)
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{
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return strnlen_user(src, 32767);
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}
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/*
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* Zero Userspace
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*/
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#ifndef __clear_user
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static inline __must_check unsigned long
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__clear_user(void __user *to, unsigned long n)
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{
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memset((void __force *)to, 0, n);
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return 0;
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}
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#endif
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static inline __must_check unsigned long
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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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return n;
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return __clear_user(to, n);
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}
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#endif /* __ASM_GENERIC_UACCESS_H */
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