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Date:      Fri, 30 Dec 2011 18:16:16 +0000 (UTC)
From:      Alan Cox <alc@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r229007 - head/sys/i386/xen
Message-ID:  <201112301816.pBUIGGHX024329@svn.freebsd.org>
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Author: alc
Date: Fri Dec 30 18:16:15 2011
New Revision: 229007
URL: http://svn.freebsd.org/changeset/base/229007

Log:
  Merge r216333 and r216555 from the native pmap
    When r207410 eliminated the acquisition and release of the page queues
    lock from pmap_extract_and_hold(), it didn't take into account that
    pmap_pte_quick() sometimes requires the page queues lock to be held.
    This change reimplements pmap_extract_and_hold() such that it no
    longer uses pmap_pte_quick(), and thus never requires the page queues
    lock.
  
  Merge r177525 from the native pmap
    Prevent the overflow in the calculation of the next page directory.
    The overflow causes the wraparound with consequent corruption of the
    (almost) whole address space mapping.
  
  Strictly speaking, r177525 is not required by the Xen pmap because the
  hypervisor steals the uppermost region of the normal kernel address
  space.  I am nonetheless merging it in order to reduce the number of
  unnecessary differences between the native and Xen pmap implementations.
  
  Tested by:	sbruno

Modified:
  head/sys/i386/xen/pmap.c

Modified: head/sys/i386/xen/pmap.c
==============================================================================
--- head/sys/i386/xen/pmap.c	Fri Dec 30 18:02:14 2011	(r229006)
+++ head/sys/i386/xen/pmap.c	Fri Dec 30 18:16:15 2011	(r229007)
@@ -1122,7 +1122,7 @@ vm_page_t
 pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, vm_prot_t prot)
 {
 	pd_entry_t pde;
-	pt_entry_t pte;
+	pt_entry_t pte, *ptep;
 	vm_page_t m;
 	vm_paddr_t pa;
 
@@ -1142,21 +1142,17 @@ retry:
 				vm_page_hold(m);
 			}
 		} else {
-			sched_pin();
-			pte = PT_GET(pmap_pte_quick(pmap, va));
-			if (*PMAP1)
-				PT_SET_MA(PADDR1, 0);
-			if ((pte & PG_V) &&
+			ptep = pmap_pte(pmap, va);
+			pte = PT_GET(ptep);
+			pmap_pte_release(ptep);
+			if (pte != 0 &&
 			    ((pte & PG_RW) || (prot & VM_PROT_WRITE) == 0)) {
 				if (vm_page_pa_tryrelock(pmap, pte & PG_FRAME,
-				    &pa)) {
-					sched_unpin();
+				    &pa))
 					goto retry;
-				}
 				m = PHYS_TO_VM_PAGE(pte & PG_FRAME);
 				vm_page_hold(m);
 			}
-			sched_unpin();
 		}
 	}
 	PA_UNLOCK_COND(pa);
@@ -2316,6 +2312,8 @@ pmap_remove(pmap_t pmap, vm_offset_t sva
 		 * Calculate index for next page table.
 		 */
 		pdnxt = (sva + NBPDR) & ~PDRMASK;
+		if (pdnxt < sva)
+			pdnxt = eva;
 		if (pmap->pm_stats.resident_count == 0)
 			break;
 
@@ -2471,6 +2469,8 @@ pmap_protect(pmap_t pmap, vm_offset_t sv
 		u_int pdirindex;
 
 		pdnxt = (sva + NBPDR) & ~PDRMASK;
+		if (pdnxt < sva)
+			pdnxt = eva;
 
 		pdirindex = sva >> PDRSHIFT;
 		ptpaddr = pmap->pm_pdir[pdirindex];
@@ -3172,6 +3172,8 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pm
 		    ("pmap_copy: invalid to pmap_copy page tables"));
 
 		pdnxt = (addr + NBPDR) & ~PDRMASK;
+		if (pdnxt < addr)
+			pdnxt = end_addr;
 		ptepindex = addr >> PDRSHIFT;
 
 		srcptepaddr = PT_GET(&src_pmap->pm_pdir[ptepindex]);

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