x86, 64-bit: create small vmemmap mappings if PSE not available

If PSE is not available, then fall back to 4k page mappings for the
vmemmap area.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 40 insertions, 22 deletions

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 363751dc3fb8..e62cbdd4e2d9 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -988,7 +988,7 @@ vmemmap_populate(struct page *start_page, unsigned long size, int node)
         pmd_t *pmd;
 
         for (; addr < end; addr = next) {
-                next = pmd_addr_end(addr, end);
+                void *p = NULL;
 
                 pgd = vmemmap_pgd_populate(addr, node);
                 if (!pgd)
@@ -998,33 +998,51 @@ vmemmap_populate(struct page *start_page, unsigned long size, int node)
                 if (!pud)
                         return -ENOMEM;
 
-                pmd = pmd_offset(pud, addr);
-                if (pmd_none(*pmd)) {
-                        pte_t entry;
-                        void *p;
+                if (!cpu_has_pse) {
+                        next = (addr + PAGE_SIZE) & PAGE_MASK;
+                        pmd = vmemmap_pmd_populate(pud, addr, node);
+
+                        if (!pmd)
+                                return -ENOMEM;
+
+                        p = vmemmap_pte_populate(pmd, addr, node);
 
-                        p = vmemmap_alloc_block(PMD_SIZE, node);
                         if (!p)
                                 return -ENOMEM;
 
-                        entry = pfn_pte(__pa(p) >> PAGE_SHIFT,
-                                                        PAGE_KERNEL_LARGE);
-                        set_pmd(pmd, __pmd(pte_val(entry)));
-
-                        /* check to see if we have contiguous blocks */
-                        if (p_end != p || node_start != node) {
-                                if (p_start)
-                                        printk(KERN_DEBUG " [%lx-%lx] PMD -> [%p-%p] on node %d\n",
-                                                addr_start, addr_end-1, p_start, p_end-1, node_start);
-                                addr_start = addr;
-                                node_start = node;
-                                p_start = p;
-                        }
-                        addr_end = addr + PMD_SIZE;
-                        p_end = p + PMD_SIZE;
+                        addr_end = addr + PAGE_SIZE;
+                        p_end = p + PAGE_SIZE;
                 } else {
-                        vmemmap_verify((pte_t *)pmd, node, addr, next);
+                        next = pmd_addr_end(addr, end);
+
+                        pmd = pmd_offset(pud, addr);
+                        if (pmd_none(*pmd)) {
+                                pte_t entry;
+
+                                p = vmemmap_alloc_block(PMD_SIZE, node);
+                                if (!p)
+                                        return -ENOMEM;
+
+                                entry = pfn_pte(__pa(p) >> PAGE_SHIFT,
+                                                PAGE_KERNEL_LARGE);
+                                set_pmd(pmd, __pmd(pte_val(entry)));
+
+                                addr_end = addr + PMD_SIZE;
+                                p_end = p + PMD_SIZE;
+
+                                /* check to see if we have contiguous blocks */
+                                if (p_end != p || node_start != node) {
+                                        if (p_start)
+                                                printk(KERN_DEBUG " [%lx-%lx] PMD -> [%p-%p] on node %d\n",
+                                                       addr_start, addr_end-1, p_start, p_end-1, node_start);
+                                        addr_start = addr;
+                                        node_start = node;
+                                        p_start = p;
+                                }
+                        } else
+                                vmemmap_verify((pte_t *)pmd, node, addr, next);
                 }
+
         }
         return 0;
 }