x86, 64-bit: split set_pte_vaddr()

We will need to set a pte on l3_user_pgt. Extract set_pte_vaddr_pud()
from set_pte_vaddr(), that will accept the l3 page table as parameter.

This change should be a no-op for existing code.
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/mm/init_64.c

@@ -144,22 +144,13 @@ static __init void *spp_getpage(void)
 }
 
 void
-set_pte_vaddr(unsigned long vaddr, pte_t new_pte)
+set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t new_pte)
 {
-	pgd_t *pgd;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
 
-	pr_debug("set_pte_vaddr %lx to %lx\n", vaddr, native_pte_val(new_pte));
-
-	pgd = pgd_offset_k(vaddr);
-	if (pgd_none(*pgd)) {
-		printk(KERN_ERR
-			"PGD FIXMAP MISSING, it should be setup in head.S!\n");
-		return;
-	}
-	pud = pud_offset(pgd, vaddr);
+	pud = pud_page + pud_index(vaddr);
 	if (pud_none(*pud)) {
 		pmd = (pmd_t *) spp_getpage();
 		pud_populate(&init_mm, pud, pmd);
@@ -192,6 +183,24 @@ set_pte_vaddr(unsigned long vaddr, pte_t new_pte)
 	__flush_tlb_one(vaddr);
 }
 
+void
+set_pte_vaddr(unsigned long vaddr, pte_t pteval)
+{
+	pgd_t *pgd;
+	pud_t *pud_page;
+
+	pr_debug("set_pte_vaddr %lx to %lx\n", vaddr, native_pte_val(pteval));
+
+	pgd = pgd_offset_k(vaddr);
+	if (pgd_none(*pgd)) {
+		printk(KERN_ERR
+			"PGD FIXMAP MISSING, it should be setup in head.S!\n");
+		return;
+	}
+	pud_page = (pud_t*)pgd_page_vaddr(*pgd);
+	set_pte_vaddr_pud(pud_page, vaddr, pteval);
+}
+
 /*
  * The head.S code sets up the kernel high mapping:
  *

include/asm-x86/pgtable_64.h

@@ -70,6 +70,9 @@ extern void paging_init(void);
 
 struct mm_struct;
 
+void set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t new_pte);
+
+
 static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr,
 				    pte_t *ptep)
 {