1/* 2 * User address space access functions. 3 * 4 * For licencing details see kernel-base/COPYING 5 */ 6 7#include <linux/uaccess.h> 8#include <linux/export.h> 9 10#include <asm/tlbflush.h> 11 12/* 13 * We rely on the nested NMI work to allow atomic faults from the NMI path; the 14 * nested NMI paths are careful to preserve CR2. 15 */ 16unsigned long 17copy_from_user_nmi(void *to, const void __user *from, unsigned long n) 18{ 19 unsigned long ret; 20 21 if (__range_not_ok(from, n, TASK_SIZE)) 22 return n; 23 24 if (!nmi_uaccess_okay()) 25 return n; 26 27 /* 28 * Even though this function is typically called from NMI/IRQ context 29 * disable pagefaults so that its behaviour is consistent even when 30 * called form other contexts. 31 */ 32 pagefault_disable(); 33 ret = __copy_from_user_inatomic(to, from, n); 34 pagefault_enable(); 35 36 return ret; 37} 38EXPORT_SYMBOL_GPL(copy_from_user_nmi); 39