[PATCH] uml: fixrange_init 3-level page table support

From: Al Viro - add three-level page table support to fixrange_init.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index f156661781cb19a2000900d195503616090de77d..c22825f13e40fda8ab8a2b21d8cc5df6fc04f6d4 100644 (file)
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -100,12 +100,37 @@ void mem_init(void)
 #endif
 }
 
+/*
+ * Create a page table and place a pointer to it in a middle page
+ * directory entry.
+ */
+static void __init one_page_table_init(pmd_t *pmd)
+{
+       if (pmd_none(*pmd)) {
+               pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
+               set_pmd(pmd, __pmd(_KERNPG_TABLE +
+                                          (unsigned long) __pa(pte)));
+               if (pte != pte_offset_kernel(pmd, 0))
+                       BUG();
+       }
+}
+
+static void __init one_md_table_init(pud_t *pud)
+{
+#ifdef CONFIG_3_LEVEL_PGTABLES
+       pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
+       set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
+       if (pmd_table != pmd_offset(pud, 0))
+               BUG();
+#endif
+}
+
 static void __init fixrange_init(unsigned long start, unsigned long end, 
                                 pgd_t *pgd_base)
 {
        pgd_t *pgd;
+       pud_t *pud;
        pmd_t *pmd;
-       pte_t *pte;
        int i, j;
        unsigned long vaddr;
 
@@ -115,15 +140,12 @@ static void __init fixrange_init(unsigned long start, unsigned long end,
        pgd = pgd_base + i;
 
        for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
-               pmd = (pmd_t *)pgd;
+               pud = pud_offset(pgd, vaddr);
+               if (pud_none(*pud))
+                       one_md_table_init(pud);
+               pmd = pmd_offset(pud, vaddr);
                for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
-                       if (pmd_none(*pmd)) {
-                               pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
-                               set_pmd(pmd, __pmd(_KERNPG_TABLE + 
-                                                  (unsigned long) __pa(pte)));
-                               if (pte != pte_offset_kernel(pmd, 0))
-                                       BUG();
-                       }
+                       one_page_table_init(pmd);
                        vaddr += PMD_SIZE;
                }
                j = 0;