1 files changed, 45 insertions, 3 deletions

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 88f1b10de3be..2cef05074413 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -138,6 +138,47 @@ static pte_t * __init one_page_table_init(pmd_t *pmd)
         return pte_offset_kernel(pmd, 0);
 }
 
+static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
+                                           unsigned long vaddr, pte_t *lastpte)
+{
+#ifdef CONFIG_HIGHMEM
+        /*
+         * Something (early fixmap) may already have put a pte
+         * page here, which causes the page table allocation
+         * to become nonlinear. Attempt to fix it, and if it
+         * is still nonlinear then we have to bug.
+         */
+        int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
+        int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
+
+        if (pmd_idx_kmap_begin != pmd_idx_kmap_end
+            && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
+            && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
+            && ((__pa(pte) >> PAGE_SHIFT) < table_start
+                || (__pa(pte) >> PAGE_SHIFT) >= table_end)) {
+                pte_t *newpte;
+                int i;
+
+                BUG_ON(after_init_bootmem);
+                newpte = alloc_low_page();
+                for (i = 0; i < PTRS_PER_PTE; i++)
+                        set_pte(newpte + i, pte[i]);
+
+                paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
+                set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
+                BUG_ON(newpte != pte_offset_kernel(pmd, 0));
+                __flush_tlb_all();
+
+                paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
+                pte = newpte;
+        }
+        BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
+               && vaddr > fix_to_virt(FIX_KMAP_END)
+               && lastpte && lastpte + PTRS_PER_PTE != pte);
+#endif
+        return pte;
+}
+
 /*
  * This function initializes a certain range of kernel virtual memory
  * with new bootmem page tables, everywhere page tables are missing in
@@ -154,6 +195,7 @@ page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
         unsigned long vaddr;
         pgd_t *pgd;
         pmd_t *pmd;
+        pte_t *pte = NULL;
 
         vaddr = start;
         pgd_idx = pgd_index(vaddr);
@@ -165,7 +207,8 @@ page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
                 pmd = pmd + pmd_index(vaddr);
                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
                                                         pmd++, pmd_idx++) {
-                        one_page_table_init(pmd);
+                        pte = page_table_kmap_check(one_page_table_init(pmd),
+                                                    pmd, vaddr, pte);
 
                         vaddr += PMD_SIZE;
                 }
@@ -508,7 +551,6 @@ static void __init early_ioremap_page_table_range_init(pgd_t *pgd_base)
          * Fixed mappings, only the page table structure has to be
          * created - mappings will be set by set_fixmap():
          */
-        early_ioremap_clear();
         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
         end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
         page_table_range_init(vaddr, end, pgd_base);
@@ -801,7 +843,7 @@ static void __init find_early_table_space(unsigned long end, int use_pse)
         tables += PAGE_ALIGN(ptes * sizeof(pte_t));
 
         /* for fixmap */
-        tables += PAGE_SIZE * 2;
+        tables += PAGE_ALIGN(__end_of_fixed_addresses * sizeof(pte_t));
 
         /*
          * RED-PEN putting page tables only on node 0 could