forked from Minki/linux
87 lines
2.2 KiB
C
87 lines
2.2 KiB
C
/*
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* User address space access functions.
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*
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* For licencing details see kernel-base/COPYING
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*/
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#include <linux/highmem.h>
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#include <linux/export.h>
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#include <asm/word-at-a-time.h>
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#include <linux/sched.h>
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/*
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* We rely on the nested NMI work to allow atomic faults from the NMI path; the
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* nested NMI paths are careful to preserve CR2.
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*/
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unsigned long
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copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
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{
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unsigned long ret;
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if (__range_not_ok(from, n, TASK_SIZE))
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return n;
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/*
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* Even though this function is typically called from NMI/IRQ context
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* disable pagefaults so that its behaviour is consistent even when
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* called form other contexts.
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*/
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pagefault_disable();
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ret = __copy_from_user_inatomic(to, from, n);
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pagefault_enable();
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return ret;
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}
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EXPORT_SYMBOL_GPL(copy_from_user_nmi);
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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 if pagefaults are
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* enabled.
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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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unsigned long _copy_to_user(void __user *to, const void *from, unsigned n)
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{
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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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EXPORT_SYMBOL(_copy_to_user);
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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 if pagefaults are
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* enabled.
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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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unsigned long _copy_from_user(void *to, const void __user *from, unsigned n)
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{
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unsigned long res = n;
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if (access_ok(VERIFY_READ, from, n))
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res = __copy_from_user_inatomic(to, from, n);
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if (unlikely(res))
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memset(to + n - res, 0, res);
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return res;
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}
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EXPORT_SYMBOL(_copy_from_user);
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