x86: update populate_extra_pte() and add populate_extra_pmd()

Impact: minor change to populate_extra_pte() and addition of pmd flavor

Update populate_extra_pte() to return pointer to the pte_t for the
specified address and add populate_extra_pmd() which only populates
till the pmd and returns pointer to the pmd entry for the address.

For 64bit, pud/pmd/pte fill functions are separated out from
set_pte_vaddr[_pud]() and used for set_pte_vaddr[_pud]() and
populate_extra_{pte|pmd}().

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 45 insertions, 30 deletions

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 7f91e2cdc4ce..7d4e76da3368 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -168,34 +168,51 @@ static __ref void *spp_getpage(void)
         return ptr;
 }
 
-void
-set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t new_pte)
+static pud_t * __init fill_pud(pgd_t *pgd, unsigned long vaddr)
 {
-        pud_t *pud;
-        pmd_t *pmd;
-        pte_t *pte;
+        if (pgd_none(*pgd)) {
+                pud_t *pud = (pud_t *)spp_getpage();
+                pgd_populate(&init_mm, pgd, pud);
+                if (pud != pud_offset(pgd, 0))
+                        printk(KERN_ERR "PAGETABLE BUG #00! %p <-> %p\n",
+                               pud, pud_offset(pgd, 0));
+        }
+        return pud_offset(pgd, vaddr);
+}
 
-        pud = pud_page + pud_index(vaddr);
+static pmd_t * __init fill_pmd(pud_t *pud, unsigned long vaddr)
+{
         if (pud_none(*pud)) {
-                pmd = (pmd_t *) spp_getpage();
+                pmd_t *pmd = (pmd_t *) spp_getpage();
                 pud_populate(&init_mm, pud, pmd);
-                if (pmd != pmd_offset(pud, 0)) {
+                if (pmd != pmd_offset(pud, 0))
                         printk(KERN_ERR "PAGETABLE BUG #01! %p <-> %p\n",
-                                pmd, pmd_offset(pud, 0));
-                        return;
-                }
+                               pmd, pmd_offset(pud, 0));
         }
-        pmd = pmd_offset(pud, vaddr);
+        return pmd_offset(pud, vaddr);
+}
+
+static pte_t * __init fill_pte(pmd_t *pmd, unsigned long vaddr)
+{
         if (pmd_none(*pmd)) {
-                pte = (pte_t *) spp_getpage();
+                pte_t *pte = (pte_t *) spp_getpage();
                 pmd_populate_kernel(&init_mm, pmd, pte);
-                if (pte != pte_offset_kernel(pmd, 0)) {
+                if (pte != pte_offset_kernel(pmd, 0))
                         printk(KERN_ERR "PAGETABLE BUG #02!\n");
-                        return;
-                }
         }
+        return pte_offset_kernel(pmd, vaddr);
+}
+
+void set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t new_pte)
+{
+        pud_t *pud;
+        pmd_t *pmd;
+        pte_t *pte;
+
+        pud = pud_page + pud_index(vaddr);
+        pmd = fill_pmd(pud, vaddr);
+        pte = fill_pte(pmd, vaddr);
 
-        pte = pte_offset_kernel(pmd, vaddr);
         set_pte(pte, new_pte);
 
         /*
@@ -205,8 +222,7 @@ set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t new_pte)
         __flush_tlb_one(vaddr);
 }
 
-void
-set_pte_vaddr(unsigned long vaddr, pte_t pteval)
+void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
 {
         pgd_t *pgd;
         pud_t *pud_page;
@@ -223,23 +239,22 @@ set_pte_vaddr(unsigned long vaddr, pte_t pteval)
         set_pte_vaddr_pud(pud_page, vaddr, pteval);
 }
 
-void __init populate_extra_pte(unsigned long vaddr)
+pmd_t * __init populate_extra_pmd(unsigned long vaddr)
 {
         pgd_t *pgd;
         pud_t *pud;
 
         pgd = pgd_offset_k(vaddr);
-        if (pgd_none(*pgd)) {
-                pud = (pud_t *)spp_getpage();
-                pgd_populate(&init_mm, pgd, pud);
-                if (pud != pud_offset(pgd, 0)) {
-                        printk(KERN_ERR "PAGETABLE BUG #00! %p <-> %p\n",
-                               pud, pud_offset(pgd, 0));
-                        return;
-                }
-        }
+        pud = fill_pud(pgd, vaddr);
+        return fill_pmd(pud, vaddr);
+}
+
+pte_t * __init populate_extra_pte(unsigned long vaddr)
+{
+        pmd_t *pmd;
 
-        set_pte_vaddr_pud((pud_t *)pgd_page_vaddr(*pgd), vaddr, __pte(0));
+        pmd = populate_extra_pmd(vaddr);
+        return fill_pte(pmd, vaddr);
 }
 
 /*