Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 mm updates from Ingo Molnar:
 "A laundry list of changes: KASAN improvements/fixes for ptdump, a
  self-test fix, PAT cleanup and wbinvd() avoidance, removal of stale
  code and documentation updates"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm/ptdump: Add address marker for KASAN shadow region
  x86/mm/ptdump: Optimize check for W+X mappings for CONFIG_KASAN=y
  x86/mm/pat: Use rb_entry()
  x86/mpx: Re-add MPX to selftests Makefile
  x86/mm: Remove CONFIG_DEBUG_NX_TEST
  x86/mm/cpa: Avoid wbinvd() for PREEMPT
  x86/mm: Improve documentation for low-level device I/O functions

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 5a287e523eab..28d42130243c 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -214,7 +214,20 @@ static void cpa_flush_array(unsigned long *start, int numpages, int cache,
 			    int in_flags, struct page **pages)
 {
 	unsigned int i, level;
+#ifdef CONFIG_PREEMPT
+	/*
+	 * Avoid wbinvd() because it causes latencies on all CPUs,
+	 * regardless of any CPU isolation that may be in effect.
+	 *
+	 * This should be extended for CAT enabled systems independent of
+	 * PREEMPT because wbinvd() does not respect the CAT partitions and
+	 * this is exposed to unpriviledged users through the graphics
+	 * subsystem.
+	 */
+	unsigned long do_wbinvd = 0;
+#else
 	unsigned long do_wbinvd = cache && numpages >= 1024; /* 4M threshold */
+#endif
 
 	BUG_ON(irqs_disabled());