The tests in this directory try to trigger the various errno
returns from perf_event_open().

See ../../doc/low_level_implementation/ERRORS.txt for more info

TODO:
	the same for the various perf-related ioctls

Not covered:
	ENOMEM	-- how to trigger out of memory?
	EBUSY	-- can this get to userspace?
	EAGAIN	-- can this get to userspace?
	ENOTTY	-- ioctl only
	ENOSYS	-- only if arch doesn't have CONFIG_HAVE_PERF_USER_STACK_DUMP
	ENODEV	-- require unsupported hardware
	
