xen/mmu: some early pagetable cleanups

1. make sure early-allocated ptes are pinned, so they can be later
   unpinned
2. don't pin pmd+pud, just make them RO
3. scatter some __inits around

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

1 files changed, 28 insertions, 12 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 67d2ab45cd90..df87c803cecc 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1013,7 +1013,7 @@ static __init int xen_mark_pinned(struct mm_struct *mm, struct page *page,
         return 0;
 }
 
-void __init xen_mark_init_mm_pinned(void)
+static void __init xen_mark_init_mm_pinned(void)
 {
         xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
 }
@@ -1461,6 +1461,15 @@ static __init void xen_set_pte_init(pte_t *ptep, pte_t pte)
 }
 #endif
 
+static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
+{
+        struct mmuext_op op;
+        op.cmd = cmd;
+        op.arg1.mfn = pfn_to_mfn(pfn);
+        if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
+                BUG();
+}
+
 /* Early in boot, while setting up the initial pagetable, assume
    everything is pinned. */
 static __init void xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
@@ -1469,22 +1478,29 @@ static __init void xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
         BUG_ON(mem_map);        /* should only be used early */
 #endif
         make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+        pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
+}
+
+/* Used for pmd and pud */
+static __init void xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
+{
+#ifdef CONFIG_FLATMEM
+        BUG_ON(mem_map);        /* should only be used early */
+#endif
+        make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
 }
 
 /* Early release_pte assumes that all pts are pinned, since there's
    only init_mm and anything attached to that is pinned. */
-static void xen_release_pte_init(unsigned long pfn)
+static __init void xen_release_pte_init(unsigned long pfn)
 {
+        pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
         make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
 }
 
-static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
+static __init void xen_release_pmd_init(unsigned long pfn)
 {
-        struct mmuext_op op;
-        op.cmd = cmd;
-        op.arg1.mfn = pfn_to_mfn(pfn);
-        if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
-                BUG();
+        make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
 }
 
 /* This needs to make sure the new pte page is pinned iff its being
@@ -1873,9 +1889,9 @@ const struct pv_mmu_ops xen_mmu_ops __initdata = {
 
         .alloc_pte = xen_alloc_pte_init,
         .release_pte = xen_release_pte_init,
-        .alloc_pmd = xen_alloc_pte_init,
+        .alloc_pmd = xen_alloc_pmd_init,
         .alloc_pmd_clone = paravirt_nop,
-        .release_pmd = xen_release_pte_init,
+        .release_pmd = xen_release_pmd_init,
 
 #ifdef CONFIG_HIGHPTE
         .kmap_atomic_pte = xen_kmap_atomic_pte,
@@ -1914,8 +1930,8 @@ const struct pv_mmu_ops xen_mmu_ops __initdata = {
         .make_pud = PV_CALLEE_SAVE(xen_make_pud),
         .set_pgd = xen_set_pgd_hyper,
 
-        .alloc_pud = xen_alloc_pte_init,
-        .release_pud = xen_release_pte_init,
+        .alloc_pud = xen_alloc_pmd_init,
+        .release_pud = xen_release_pmd_init,
 #endif  /* PAGETABLE_LEVELS == 4 */
 
         .activate_mm = xen_activate_mm,