tree a4ff5c8ddf932920fc2700e261f92c08b293d040
parent 5398f9854f60d670e8ef1ea08c0e0310f253eeb1
author Arjan van de Ven <arjan@linux.intel.com> 1201696447 +0100
committer Ingo Molnar <mingo@elte.hu> 1201696447 +0100

x86: fix pageattr-selftest

In Ingo's testing, he found a bug in the CPA selftest code. What would
happen is that the test would call change_page_attr_addr on a range of
memory, part of which was read only, part of which was writable. The
only thing the test wanted to change was the global bit...

What actually happened was that the selftest would take the permissions
of the first page, and then the change_page_attr_addr call would then
set the permissions of the entire range to this first page. In the
rodata section case, this resulted in pages after the .rodata becoming
read only... which made the kernel rather unhappy in many interesting
ways.

This is just another example of how dangerous the cpa API is (was); this
patch changes the test to use the incremental clear/set APIs
instead, and it changes the clear/set implementation to work on a 1 page
at a time basis.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>