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