xen/mmu/p2m: Refactor the xen_pagetable_init code (v2).

The revectoring and copying of the P2M only happens when
!auto-xlat and on 64-bit builds. It is not obvious from
the code, so lets have seperate 32 and 64-bit functions.

We also invert the check for auto-xlat to make the code
flow simpler.

Suggested-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 37 insertions, 33 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index ce563be09cc1..c140efffe37e 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1198,44 +1198,40 @@ static void __init xen_cleanhighmap(unsigned long vaddr,
          * instead of somewhere later and be confusing. */
         xen_mc_flush();
 }
-#endif
-static void __init xen_pagetable_init(void)
+static void __init xen_pagetable_p2m_copy(void)
 {
-#ifdef CONFIG_X86_64
         unsigned long size;
         unsigned long addr;
-#endif
-        paging_init();
-        xen_setup_shared_info();
-#ifdef CONFIG_X86_64
-        if (!xen_feature(XENFEAT_auto_translated_physmap)) {
-                unsigned long new_mfn_list;
+        unsigned long new_mfn_list;
+
+        if (xen_feature(XENFEAT_auto_translated_physmap))
+                return;
+
+        size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
+
+        /* On 32-bit, we get zero so this never gets executed. */
+        new_mfn_list = xen_revector_p2m_tree();
+        if (new_mfn_list && new_mfn_list != xen_start_info->mfn_list) {
+                /* using __ka address and sticking INVALID_P2M_ENTRY! */
+                memset((void *)xen_start_info->mfn_list, 0xff, size);
+
+                /* We should be in __ka space. */
+                BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map);
+                addr = xen_start_info->mfn_list;
+                /* We roundup to the PMD, which means that if anybody at this stage is
+                 * using the __ka address of xen_start_info or xen_start_info->shared_info
+                 * they are in going to crash. Fortunatly we have already revectored
+                 * in xen_setup_kernel_pagetable and in xen_setup_shared_info. */
+                size = roundup(size, PMD_SIZE);
+                xen_cleanhighmap(addr, addr + size);
 
                 size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
+                memblock_free(__pa(xen_start_info->mfn_list), size);
+                /* And revector! Bye bye old array */
+                xen_start_info->mfn_list = new_mfn_list;
+        } else
+                return;
 
-                /* On 32-bit, we get zero so this never gets executed. */
-                new_mfn_list = xen_revector_p2m_tree();
-                if (new_mfn_list && new_mfn_list != xen_start_info->mfn_list) {
-                        /* using __ka address and sticking INVALID_P2M_ENTRY! */
-                        memset((void *)xen_start_info->mfn_list, 0xff, size);
-
-                        /* We should be in __ka space. */
-                        BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map);
-                        addr = xen_start_info->mfn_list;
-                        /* We roundup to the PMD, which means that if anybody at this stage is
-                         * using the __ka address of xen_start_info or xen_start_info->shared_info
-                         * they are in going to crash. Fortunatly we have already revectored
-                         * in xen_setup_kernel_pagetable and in xen_setup_shared_info. */
-                        size = roundup(size, PMD_SIZE);
-                        xen_cleanhighmap(addr, addr + size);
-
-                        size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
-                        memblock_free(__pa(xen_start_info->mfn_list), size);
-                        /* And revector! Bye bye old array */
-                        xen_start_info->mfn_list = new_mfn_list;
-                } else
-                        goto skip;
-        }
         /* At this stage, cleanup_highmap has already cleaned __ka space
          * from _brk_limit way up to the max_pfn_mapped (which is the end of
          * the ramdisk). We continue on, erasing PMD entries that point to page
@@ -1255,7 +1251,15 @@ static void __init xen_pagetable_init(void)
          * anything at this stage. */
         xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1);
 #endif
-skip:
+}
+#endif
+
+static void __init xen_pagetable_init(void)
+{
+        paging_init();
+        xen_setup_shared_info();
+#ifdef CONFIG_X86_64
+        xen_pagetable_p2m_copy();
 #endif
         xen_post_allocator_init();
 }