svn commit: r261918 - head/sys/arm/arm

[Zbigniew Bodek]

Author: zbb
Date: Sat Feb 15 13:17:51 2014
New Revision: 261918
URL: http://svnweb.freebsd.org/changeset/base/261918

Log:
  Ensure proper TLB invalidation on superpage promotion and demotion on ARM
  
  Base pages within newly created superpage need to be invalidated so that
  new mapping is "visible" immediately after creation.

Modified:
  head/sys/arm/arm/pmap-v6.c

Modified: head/sys/arm/arm/pmap-v6.c
==============================================================================
--- head/sys/arm/arm/pmap-v6.c	Sat Feb 15 13:13:00 2014	(r261917)
+++ head/sys/arm/arm/pmap-v6.c	Sat Feb 15 13:17:51 2014	(r261918)
@@ -3854,6 +3854,24 @@ pmap_promote_section(pmap_t pmap, vm_off
 	 * Map the superpage.
 	 */
 	pmap_map_section(pmap, first_va, l2pte_pa(firstpte), prot, TRUE);
+	/*
+	 * Invalidate all possible TLB mappings for small
+	 * pages within the newly created superpage.
+	 * Rely on the first PTE's attributes since they
+	 * have to be consistent across all of the base pages
+	 * within the superpage. If page is not executable it
+	 * is at least referenced.
+	 * The fastest way to do that is to invalidate whole
+	 * TLB at once instead of executing 256 CP15 TLB
+	 * invalidations by single entry. TLBs usually maintain
+	 * several dozen entries so loss of unrelated entries is
+	 * still a less agresive approach.
+	 */
+	if (L2_S_EXECUTABLE(firstpte))
+		cpu_tlb_flushID();
+	else
+		cpu_tlb_flushD();
+
 	pmap_section_promotions++;
 	CTR2(KTR_PMAP, "pmap_promote_section: success for va %#x"
 	    " in pmap %p", first_va, pmap);
@@ -3889,7 +3907,7 @@ pmap_demote_section(pmap_t pmap, vm_offs
 	struct l2_bucket *l2b;
 	struct pv_entry *l1pdpve;
 	struct md_page *pvh;
-	pd_entry_t *pl1pd, l1pd;
+	pd_entry_t *pl1pd, l1pd, newl1pd;
 	pt_entry_t *firstptep, newpte;
 	vm_offset_t pa;
 	vm_page_t m;
@@ -3969,9 +3987,14 @@ pmap_demote_section(pmap_t pmap, vm_offs
 	pmap_pv_demote_section(pmap, va, pa);
 
 	/* Now fix-up L1 */
-	l1pd = l2b->l2b_phys | L1_C_DOM(pmap->pm_domain) | L1_C_PROTO;
-	*pl1pd = l1pd;
+	newl1pd = l2b->l2b_phys | L1_C_DOM(pmap->pm_domain) | L1_C_PROTO;
+	*pl1pd = newl1pd;
 	PTE_SYNC(pl1pd);
+	/* Invalidate old TLB mapping */
+	if (L1_S_EXECUTABLE(l1pd))
+		cpu_tlb_flushID_SE(va);
+	else if (L1_S_REFERENCED(l1pd))
+		cpu_tlb_flushD_SE(va);
 
 	pmap_section_demotions++;
 	CTR2(KTR_PMAP, "pmap_demote_section: success for va %#x"