x86: create a non-zero sized bm_pte only when needed

[net-next-2.6.git] / arch / x86 / mm / ioremap.c

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 83ed74affba9f9ac1cd0c484104835ba53356493..55e127f71ed9014348e4b5935274849ddd264fff 100644 (file)
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -487,7 +487,12 @@ static int __init early_ioremap_debug_setup(char *str)
 early_param("early_ioremap_debug", early_ioremap_debug_setup);
 
 static __initdata int after_paging_init;
-static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss;
+#define __FIXADDR_TOP (-PAGE_SIZE)
+static pte_t bm_pte[(__fix_to_virt(FIX_DBGP_BASE)
+                    ^ __fix_to_virt(FIX_BTMAP_BEGIN)) >> PMD_SHIFT
+                   ? PAGE_SIZE / sizeof(pte_t) : 0] __page_aligned_bss;
+#undef __FIXADDR_TOP
+static __initdata pte_t *bm_ptep;
 
 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
 {
@@ -502,6 +507,8 @@ static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
 
 static inline pte_t * __init early_ioremap_pte(unsigned long addr)
 {
+       if (!sizeof(bm_pte))
+               return &bm_ptep[pte_index(addr)];
        return &bm_pte[pte_index(addr)];
 }
 
@@ -519,8 +526,14 @@ void __init early_ioremap_init(void)
                slot_virt[i] = fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
 
        pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
-       memset(bm_pte, 0, sizeof(bm_pte));
-       pmd_populate_kernel(&init_mm, pmd, bm_pte);
+       if (sizeof(bm_pte)) {
+               memset(bm_pte, 0, sizeof(bm_pte));
+               pmd_populate_kernel(&init_mm, pmd, bm_pte);
+       } else {
+               bm_ptep = pte_offset_kernel(pmd, 0);
+               if (early_ioremap_debug)
+                       printk(KERN_INFO "bm_ptep=%p\n", bm_ptep);
+       }
 
        /*
         * The boot-ioremap range spans multiple pmds, for which