1*4882a593Smuzhiyun /* 2*4882a593Smuzhiyun * User address space access functions. 3*4882a593Smuzhiyun * 4*4882a593Smuzhiyun * For licencing details see kernel-base/COPYING 5*4882a593Smuzhiyun */ 6*4882a593Smuzhiyun 7*4882a593Smuzhiyun #include <linux/uaccess.h> 8*4882a593Smuzhiyun #include <linux/export.h> 9*4882a593Smuzhiyun 10*4882a593Smuzhiyun #include <asm/tlbflush.h> 11*4882a593Smuzhiyun 12*4882a593Smuzhiyun /* 13*4882a593Smuzhiyun * We rely on the nested NMI work to allow atomic faults from the NMI path; the 14*4882a593Smuzhiyun * nested NMI paths are careful to preserve CR2. 15*4882a593Smuzhiyun */ 16*4882a593Smuzhiyun unsigned long copy_from_user_nmi(void * to,const void __user * from,unsigned long n)17*4882a593Smuzhiyuncopy_from_user_nmi(void *to, const void __user *from, unsigned long n) 18*4882a593Smuzhiyun { 19*4882a593Smuzhiyun unsigned long ret; 20*4882a593Smuzhiyun 21*4882a593Smuzhiyun if (__range_not_ok(from, n, TASK_SIZE)) 22*4882a593Smuzhiyun return n; 23*4882a593Smuzhiyun 24*4882a593Smuzhiyun if (!nmi_uaccess_okay()) 25*4882a593Smuzhiyun return n; 26*4882a593Smuzhiyun 27*4882a593Smuzhiyun /* 28*4882a593Smuzhiyun * Even though this function is typically called from NMI/IRQ context 29*4882a593Smuzhiyun * disable pagefaults so that its behaviour is consistent even when 30*4882a593Smuzhiyun * called form other contexts. 31*4882a593Smuzhiyun */ 32*4882a593Smuzhiyun pagefault_disable(); 33*4882a593Smuzhiyun ret = __copy_from_user_inatomic(to, from, n); 34*4882a593Smuzhiyun pagefault_enable(); 35*4882a593Smuzhiyun 36*4882a593Smuzhiyun return ret; 37*4882a593Smuzhiyun } 38*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(copy_from_user_nmi); 39