From 02fe5df62ac5b5689db023b7404b39e6395cca9b Mon Sep 17 00:00:00 2001
From: Jeremy Fitzhardinge <jeremy@goop.org>
Date: Wed, 13 Oct 2010 16:02:24 -0700
Subject: [PATCH] --- yaml --- r: 212751 b: refs/heads/master c:
 fef5ba797991f9335bcfc295942b684f9bf613a1 h: refs/heads/master i:   212749:
 77f55c09bd4e61e718742e7584af08631c378c1d   212747:
 d1e0d14cd9e2c16a024c4eca04e9186722ba97e7   212743:
 1067a8241a585470f35d737ca1343352ec9ae047   212735:
 2a49a0350bff4f52c683dd55aede41a3843159e5 v: v3

---
 [refs]                          |  2 +-
 trunk/arch/x86/include/asm/io.h |  1 +
 trunk/arch/x86/mm/ioremap.c     |  5 +++++
 trunk/arch/x86/xen/mmu.c        | 26 ++++++++++++++++++--------
 4 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/[refs] b/[refs]
index 2ef239d66bc4..d4c824733731 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c7fc2de0c83dbd2eaf759c5cd0e2b9cf1eb4df3a
+refs/heads/master: fef5ba797991f9335bcfc295942b684f9bf613a1
diff --git a/trunk/arch/x86/include/asm/io.h b/trunk/arch/x86/include/asm/io.h
index 30a3e9776123..66aee6c4123b 100644
--- a/trunk/arch/x86/include/asm/io.h
+++ b/trunk/arch/x86/include/asm/io.h
@@ -348,6 +348,7 @@ extern void __iomem *early_memremap(resource_size_t phys_addr,
 				    unsigned long size);
 extern void early_iounmap(void __iomem *addr, unsigned long size);
 extern void fixup_early_ioremap(void);
+extern bool is_early_ioremap_ptep(pte_t *ptep);
 
 #define IO_SPACE_LIMIT 0xffff
 
diff --git a/trunk/arch/x86/mm/ioremap.c b/trunk/arch/x86/mm/ioremap.c
index 3ba6e0608c55..0369843511dc 100644
--- a/trunk/arch/x86/mm/ioremap.c
+++ b/trunk/arch/x86/mm/ioremap.c
@@ -362,6 +362,11 @@ static inline pte_t * __init early_ioremap_pte(unsigned long addr)
 	return &bm_pte[pte_index(addr)];
 }
 
+bool __init is_early_ioremap_ptep(pte_t *ptep)
+{
+	return ptep >= &bm_pte[0] && ptep < &bm_pte[PAGE_SIZE/sizeof(pte_t)];
+}
+
 static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
 
 void __init early_ioremap_init(void)
diff --git a/trunk/arch/x86/xen/mmu.c b/trunk/arch/x86/xen/mmu.c
index 4fe04ac0bae0..7d55e9ee3a76 100644
--- a/trunk/arch/x86/xen/mmu.c
+++ b/trunk/arch/x86/xen/mmu.c
@@ -56,6 +56,7 @@
 #include <asm/e820.h>
 #include <asm/linkage.h>
 #include <asm/page.h>
+#include <asm/init.h>
 
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
@@ -360,7 +361,8 @@ void make_lowmem_page_readonly(void *vaddr)
 	unsigned int level;
 
 	pte = lookup_address(address, &level);
-	BUG_ON(pte == NULL);
+	if (pte == NULL)
+		return;		/* vaddr missing */
 
 	ptev = pte_wrprotect(*pte);
 
@@ -375,7 +377,8 @@ void make_lowmem_page_readwrite(void *vaddr)
 	unsigned int level;
 
 	pte = lookup_address(address, &level);
-	BUG_ON(pte == NULL);
+	if (pte == NULL)
+		return;		/* vaddr missing */
 
 	ptev = pte_mkwrite(*pte);
 
@@ -1509,13 +1512,25 @@ static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
 #endif
 }
 
-#ifdef CONFIG_X86_32
 static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
 {
+	unsigned long pfn = pte_pfn(pte);
+
+#ifdef CONFIG_X86_32
 	/* If there's an existing pte, then don't allow _PAGE_RW to be set */
 	if (pte_val_ma(*ptep) & _PAGE_PRESENT)
 		pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
 			       pte_val_ma(pte));
+#endif
+
+	/*
+	 * If the new pfn is within the range of the newly allocated
+	 * kernel pagetable, and it isn't being mapped into an
+	 * early_ioremap fixmap slot, make sure it is RO.
+	 */
+	if (!is_early_ioremap_ptep(ptep) &&
+	    pfn >= e820_table_start && pfn < e820_table_end)
+		pte = pte_wrprotect(pte);
 
 	return pte;
 }
@@ -1528,7 +1543,6 @@ static __init void xen_set_pte_init(pte_t *ptep, pte_t pte)
 
 	xen_set_pte(ptep, pte);
 }
-#endif
 
 static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
 {
@@ -1973,11 +1987,7 @@ static const struct pv_mmu_ops xen_mmu_ops __initdata = {
 	.alloc_pmd_clone = paravirt_nop,
 	.release_pmd = xen_release_pmd_init,
 
-#ifdef CONFIG_X86_64
-	.set_pte = xen_set_pte,
-#else
 	.set_pte = xen_set_pte_init,
-#endif
 	.set_pte_at = xen_set_pte_at,
 	.set_pmd = xen_set_pmd_hyper,