xen: don't drop NX bit

Because NX is now enforced properly, we must put the hypercall page
into the .text segment so that it is executable.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
Cc: the arch/x86 maintainers <x86@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 31 insertions, 25 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index f0078d9a5b78..8132aa8c5d49 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -323,46 +323,54 @@ out:
                 preempt_enable();
 }
 
-pteval_t xen_pte_val(pte_t pte)
+/* Assume pteval_t is equivalent to all the other *val_t types. */
+static pteval_t pte_mfn_to_pfn(pteval_t val)
 {
-        pteval_t ret = pte.pte;
+        if (val & _PAGE_PRESENT) {
+                unsigned long mfn = (val & PTE_MASK) >> PAGE_SHIFT;
+                pteval_t flags = val & ~PTE_MASK;
+                val = (mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
+        }
 
-        if (ret & _PAGE_PRESENT)
-                ret = machine_to_phys(XMADDR(ret)).paddr | _PAGE_PRESENT;
+        return val;
+}
 
-        return ret;
+static pteval_t pte_pfn_to_mfn(pteval_t val)
+{
+        if (val & _PAGE_PRESENT) {
+                unsigned long pfn = (val & PTE_MASK) >> PAGE_SHIFT;
+                pteval_t flags = val & ~PTE_MASK;
+                val = (pfn_to_mfn(pfn) << PAGE_SHIFT) | flags;
+        }
+
+        return val;
+}
+
+pteval_t xen_pte_val(pte_t pte)
+{
+        return pte_mfn_to_pfn(pte.pte);
 }
 
 pgdval_t xen_pgd_val(pgd_t pgd)
 {
-        pgdval_t ret = pgd.pgd;
-        if (ret & _PAGE_PRESENT)
-                ret = machine_to_phys(XMADDR(ret)).paddr | _PAGE_PRESENT;
-        return ret;
+        return pte_mfn_to_pfn(pgd.pgd);
 }
 
 pte_t xen_make_pte(pteval_t pte)
 {
-        if (pte & _PAGE_PRESENT)
-                pte = phys_to_machine(XPADDR(pte)).maddr;
-
-        return (pte_t){ .pte = pte };
+        pte = pte_pfn_to_mfn(pte);
+        return native_make_pte(pte);
 }
 
 pgd_t xen_make_pgd(pgdval_t pgd)
 {
-        if (pgd & _PAGE_PRESENT)
-                pgd = phys_to_machine(XPADDR(pgd)).maddr;
-
-        return (pgd_t){ pgd };
+        pgd = pte_pfn_to_mfn(pgd);
+        return native_make_pgd(pgd);
 }
 
 pmdval_t xen_pmd_val(pmd_t pmd)
 {
-        pmdval_t ret = native_pmd_val(pmd);
-        if (ret & _PAGE_PRESENT)
-                ret = machine_to_phys(XMADDR(ret)).paddr | _PAGE_PRESENT;
-        return ret;
+        return pte_mfn_to_pfn(pmd.pmd);
 }
 
 void xen_set_pud_hyper(pud_t *ptr, pud_t val)
@@ -421,9 +429,7 @@ void xen_pmd_clear(pmd_t *pmdp)
 
 pmd_t xen_make_pmd(pmdval_t pmd)
 {
-        if (pmd & _PAGE_PRESENT)
-                pmd = phys_to_machine(XPADDR(pmd)).maddr;
-
+        pmd = pte_pfn_to_mfn(pmd);
         return native_make_pmd(pmd);
 }
 
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
index ef6c9e005f90..7c0cf6320a0a 100644
--- a/arch/x86/xen/xen-head.S
+++ b/arch/x86/xen/xen-head.S
@@ -18,7 +18,7 @@ ENTRY(startup_xen)
 
         __FINIT
 
-.pushsection .bss.page_aligned
+.pushsection .text
         .align PAGE_SIZE_asm
 ENTRY(hypercall_page)
         .skip 0x1000