Author: jeff
Date: Mon Aug 5 00:28:03 2013
New Revision: 253949
URL: http://svnweb.freebsd.org/changeset/base/253949
Log:
- Introduce a specific function, pmap_remove_kernel_pde, for removing
huge pages in the kernel's address space. This works around several
asserts from pmap_demote_pde_locked that did not apply and gave false
warnings.
Discovered by: pho
Reviewed by: alc
Sponsored by: EMC / Isilon Storage Division
Modified:
head/sys/amd64/amd64/pmap.c
head/sys/i386/i386/pmap.c
Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c Sun Aug 4 23:45:04 2013 (r253948)
+++ head/sys/amd64/amd64/pmap.c Mon Aug 5 00:28:03 2013 (r253949)
@@ -2795,6 +2795,44 @@ pmap_demote_pde_locked(pmap_t pmap, pd_e
}
/*
+ * pmap_remove_kernel_pde: Remove a kernel superpage mapping.
+ */
+static void
+pmap_remove_kernel_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t va)
+{
+ pd_entry_t newpde;
+ vm_paddr_t mptepa;
+ vm_page_t mpte;
+
+ PMAP_LOCK_ASSERT(pmap, MA_OWNED);
+ mpte = pmap_lookup_pt_page(pmap, va);
+ if (mpte == NULL)
+ panic("pmap_remove_kernel_pde: Missing pt page.");
+
+ pmap_remove_pt_page(pmap, mpte);
+ mptepa = VM_PAGE_TO_PHYS(mpte);
+ newpde = mptepa | PG_M | PG_A | PG_RW | PG_V;
+
+ /*
+ * Initialize the page table page.
+ */
+ pagezero((void *)PHYS_TO_DMAP(mptepa));
+
+ /*
+ * Demote the mapping.
+ */
+ if (workaround_erratum383)
+ pmap_update_pde(pmap, va, pde, newpde);
+ else
+ pde_store(pde, newpde);
+
+ /*
+ * Invalidate a stale recursive mapping of the page table page.
+ */
+ pmap_invalidate_page(pmap, (vm_offset_t)vtopte(va));
+}
+
+/*
* pmap_remove_pde: do the things to unmap a superpage in a process
*/
static int
@@ -2837,8 +2875,7 @@ pmap_remove_pde(pmap_t pmap, pd_entry_t
}
}
if (pmap == kernel_pmap) {
- if (!pmap_demote_pde_locked(pmap, pdq, sva, lockp))
- panic("pmap_remove_pde: failed demotion");
+ pmap_remove_kernel_pde(pmap, pdq, sva);
} else {
mpte = pmap_lookup_pt_page(pmap, sva);
if (mpte != NULL) {
Modified: head/sys/i386/i386/pmap.c
==============================================================================
--- head/sys/i386/i386/pmap.c Sun Aug 4 23:45:04 2013 (r253948)
+++ head/sys/i386/i386/pmap.c Mon Aug 5 00:28:03 2013 (r253949)
@@ -2773,6 +2773,44 @@ pmap_demote_pde(pmap_t pmap, pd_entry_t
}
/*
+ * Removes a 2- or 4MB page mapping from the kernel pmap.
+ */
+static void
+pmap_remove_kernel_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t va)
+{
+ pd_entry_t newpde;
+ vm_paddr_t mptepa;
+ vm_page_t mpte;
+
+ PMAP_LOCK_ASSERT(pmap, MA_OWNED);
+ mpte = pmap_lookup_pt_page(pmap, va);
+ if (mpte == NULL)
+ panic("pmap_remove_kernel_pde: Missing pt page.");
+
+ pmap_remove_pt_page(pmap, mpte);
+ mptepa = VM_PAGE_TO_PHYS(mpte);
+ newpde = mptepa | PG_M | PG_A | PG_RW | PG_V;
+
+ /*
+ * Initialize the page table page.
+ */
+ pagezero((void *)&KPTmap[i386_btop(trunc_4mpage(va))]);
+
+ /*
+ * Remove the mapping.
+ */
+ if (workaround_erratum383)
+ pmap_update_pde(pmap, va, pde, newpde);
+ else
+ pmap_kenter_pde(va, newpde);
+
+ /*
+ * Invalidate the recursive mapping of the page table page.
+ */
+ pmap_invalidate_page(pmap, (vm_offset_t)vtopte(va));
+}
+
+/*
* pmap_remove_pde: do the things to unmap a superpage in a process
*/
static void
@@ -2814,8 +2852,7 @@ pmap_remove_pde(pmap_t pmap, pd_entry_t
}
}
if (pmap == kernel_pmap) {
- if (!pmap_demote_pde(pmap, pdq, sva))
- panic("pmap_remove_pde: failed demotion");
+ pmap_remove_kernel_pde(pmap, pdq, sva);
} else {
mpte = pmap_lookup_pt_page(pmap, sva);
if (mpte != NULL) {
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