Author: kib
Date: Fri May 31 19:13:31 2019
New Revision: 348479
URL: https://svnweb.freebsd.org/changeset/base/348479
Log:
MFC r348246:
Fix a corner case in demotion of kernel mappings.
Modified:
stable/12/sys/amd64/amd64/pmap.c
stable/12/sys/i386/i386/pmap.c
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/sys/amd64/amd64/pmap.c
==============================================================================
--- stable/12/sys/amd64/amd64/pmap.c Fri May 31 19:09:56 2019
(r348478)
+++ stable/12/sys/amd64/amd64/pmap.c Fri May 31 19:13:31 2019
(r348479)
@@ -4167,8 +4167,10 @@ pmap_demote_pde_locked(pmap_t pmap, pd_entry_t *pde, v
" in pmap %p", va, pmap);
return (FALSE);
}
- if (va < VM_MAXUSER_ADDRESS)
+ if (va < VM_MAXUSER_ADDRESS) {
+ mpte->wire_count = NPTEPG;
pmap_resident_count_inc(pmap, 1);
+ }
}
mptepa = VM_PAGE_TO_PHYS(mpte);
firstpte = (pt_entry_t *)PHYS_TO_DMAP(mptepa);
@@ -4181,12 +4183,12 @@ pmap_demote_pde_locked(pmap_t pmap, pd_entry_t *pde, v
newpte = pmap_swap_pat(pmap, newpte);
/*
- * If the page table page is new, initialize it.
+ * If the page table page is not leftover from an earlier promotion,
+ * initialize it.
*/
- if (mpte->wire_count == 1) {
- mpte->wire_count = NPTEPG;
+ if ((oldpde & PG_PROMOTED) == 0)
pmap_fill_ptp(firstpte, newpte);
- }
+
KASSERT((*firstpte & PG_FRAME) == (newpte & PG_FRAME),
("pmap_demote_pde: firstpte and newpte map different physical"
" addresses"));
Modified: stable/12/sys/i386/i386/pmap.c
==============================================================================
--- stable/12/sys/i386/i386/pmap.c Fri May 31 19:09:56 2019
(r348478)
+++ stable/12/sys/i386/i386/pmap.c Fri May 31 19:13:31 2019
(r348479)
@@ -2845,8 +2845,10 @@ pmap_demote_pde(pmap_t pmap, pd_entry_t *pde, vm_offse
" in pmap %p", va, pmap);
return (FALSE);
}
- if (pmap != kernel_pmap)
+ if (pmap != kernel_pmap) {
+ mpte->wire_count = NPTEPG;
pmap->pm_stats.resident_count++;
+ }
}
mptepa = VM_PAGE_TO_PHYS(mpte);
@@ -2894,12 +2896,12 @@ pmap_demote_pde(pmap_t pmap, pd_entry_t *pde, vm_offse
newpte ^= PG_PDE_PAT | PG_PTE_PAT;
/*
- * If the page table page is new, initialize it.
+ * If the page table page is not leftover from an earlier promotion,
+ * initialize it.
*/
- if (mpte->wire_count == 1) {
- mpte->wire_count = NPTEPG;
+ if ((oldpde & PG_PROMOTED) == 0)
pmap_fill_ptp(firstpte, newpte);
- }
+
KASSERT((*firstpte & PG_FRAME) == (newpte & PG_FRAME),
("pmap_demote_pde: firstpte and newpte map different physical"
" addresses"));
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