blob: c3e8a62ca561a0aa3eb81f7059916a172b1ec305 [file] [log] [blame]
* User address space access functions.
* For licencing details see kernel-base/COPYING
#include <linux/uaccess.h>
#include <linux/export.h>
#include <asm/tlbflush.h>
* copy_from_user_nmi - NMI safe copy from user
* @to: Pointer to the destination buffer
* @from: Pointer to a user space address of the current task
* @n: Number of bytes to copy
* Returns: The number of not copied bytes. 0 is success, i.e. all bytes copied
* Contrary to other copy_from_user() variants this function can be called
* from NMI context. Despite the name it is not restricted to be called
* from NMI context. It is safe to be called from any other context as
* well. It disables pagefaults across the copy which means a fault will
* abort the copy.
* For NMI context invocations this relies on the nested NMI work to allow
* atomic faults from the NMI path; the nested NMI paths are careful to
* preserve CR2.
unsigned long
copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
unsigned long ret;
if (__range_not_ok(from, n, TASK_SIZE))
return n;
if (!nmi_uaccess_okay())
return n;
* Even though this function is typically called from NMI/IRQ context
* disable pagefaults so that its behaviour is consistent even when
* called from other contexts.
ret = __copy_from_user_inatomic(to, from, n);
return ret;