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>

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index ce563be..c140eff 100644 (file)
--- 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();
 }