Tracepoints are named hierachially, and it makes more sense to keep a
general flow of information level from general to specific from left
to right, i.e.

	x86_exceptions.page_fault_user|kernel

rather than

	x86_exceptions.user|kernel_page_fault
Suggested-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NSeiji Aguchi <seiji.aguchi@hds.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/20131111082955.GB12405@gmail.com

This patch introduces page fault tracepoints to x86 architecture
by switching IDT.

  Two events, for user and kernel spaces, are introduced at the beginning
  of page fault handler for tracing.

  - User space event
    There is a request of page fault event for user space as below.

    https://lkml.kernel.org/r/1368079520-11015-2-git-send-email-fdeslaur+()+gmail+!+com
    https://lkml.kernel.org/r/1368079520-11015-1-git-send-email-fdeslaur+()+gmail+!+com

  - Kernel space event:
    When we measure an overhead in kernel space for investigating performance
    issues, we can check if it comes from the page fault events.
Signed-off-by: NSeiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/52716E67.6090705@hds.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>