LXR linux/arch/x86/lib/usercopy.c

   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 */
  17unsigned long
  18copy_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 0;
  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}
  36EXPORT_SYMBOL_GPL(copy_from_user_nmi);
  37