svn commit: r336001 - head/sys/vm

[Konstantin Belousov]

Author: kib
Date: Thu Jul  5 16:43:15 2018
New Revision: 336001
URL: https://svnweb.freebsd.org/changeset/base/336001

Log:
  Copyout(9) on 4/4 i386 needs correct vm_page_array[].
  
  On the 4/4 i386, copyout(9) may need to call pmap_extract_and_hold()
  on arbitrary userspace mapping.  If the mapping is backed by the
  non-managed cdev pager or by the sg pager, on dense configs we might
  access arbitrary element of vm_page_array[], in particular, not
  corresponding to a page from the memory segment.  Initialize such pages
  as fictitious with the corresponding physical address.
  
  Reported by:	bde
  Reviewed by:	alc, markj (previous version)
  Sponsored by:	The FreeBSD Foundation
  Differential revision:	https://reviews.freebsd.org/D16085

Modified:
  head/sys/vm/vm_page.c

Modified: head/sys/vm/vm_page.c
==============================================================================
--- head/sys/vm/vm_page.c	Thu Jul  5 16:40:20 2018	(r336000)
+++ head/sys/vm/vm_page.c	Thu Jul  5 16:43:15 2018	(r336001)
@@ -551,6 +551,9 @@ vm_page_startup(vm_offset_t vaddr)
 	vm_paddr_t biggestsize, last_pa, pa;
 	u_long pagecount;
 	int biggestone, i, segind;
+#if defined(__i386__) && defined(VM_PHYSSEG_DENSE)
+	long ii;
+#endif
 
 	biggestsize = 0;
 	biggestone = 0;
@@ -789,6 +792,13 @@ vm_page_startup(vm_offset_t vaddr)
 	 * Initialize the page structures and add every available page to the
 	 * physical memory allocator's free lists.
 	 */
+#if defined(__i386__) && defined(VM_PHYSSEG_DENSE)
+	for (ii = 0; ii < vm_page_array_size; ii++) {
+		m = &vm_page_array[ii];
+		vm_page_init_page(m, (first_page + ii) << PAGE_SHIFT, 0);
+		m->flags = PG_FICTITIOUS;
+	}
+#endif
 	vm_cnt.v_page_count = 0;
 	for (segind = 0; segind < vm_phys_nsegs; segind++) {
 		seg = &vm_phys_segs[segind];