[PATCH 1/9] prepare pmap helpers for full 64 bit memory map

[Luca Dariz]

* i386/intel/pmap.c: start walking the page table tree from the L4
  table instead of the PDP table in pmap_pte() and pmap_pde(),
  preparing for the kernel to run on high addresses.
---
 i386/intel/pmap.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)
diff --git a/i386/intel/pmap.c b/i386/intel/pmap.c
index 615b0fff..9fe16368 100644
--- a/i386/intel/pmap.c
+++ b/i386/intel/pmap.c
@@ -437,10 +437,22 @@ pmap_pde(const pmap_t pmap, vm_offset_t addr)
        if (pmap == kernel_pmap)
                addr = kvtolin(addr);
 #if PAE
-       page_dir = (pt_entry_t *) ptetokv(pmap->pdpbase[lin2pdpnum(addr)]);
-#else
+       pt_entry_t *pdp_table, pdp, pde;
+#ifdef __x86_64__
+       pdp = pmap->l4base[lin2l4num(addr)];
+       if ((pdp & INTEL_PTE_VALID) == 0)
+               return PT_ENTRY_NULL;
+       pdp_table = (pt_entry_t *) ptetokv(pdp);
+#else /* __x86_64__ */
+       pdp_table = pmap->pdpbase;
+#endif /* __x86_64__ */
+       pde = pdp_table[lin2pdpnum(addr)];
+       if ((pde & INTEL_PTE_VALID) == 0)
+               return PT_ENTRY_NULL;
+       page_dir = (pt_entry_t *) ptetokv(pde);
+#else /* PAE */
        page_dir = pmap->dirbase;
-#endif
+#endif /* PAE */
        return &page_dir[lin2pdenum(addr)];
 }
 
@@ -457,14 +469,20 @@ pmap_pte(const pmap_t pmap, vm_offset_t addr)
        pt_entry_t      *ptp;
        pt_entry_t      pte;
 
-#if PAE
+#ifdef __x86_64__
+       if (pmap->l4base == 0)
+               return(PT_ENTRY_NULL);
+#elif PAE
        if (pmap->pdpbase == 0)
                return(PT_ENTRY_NULL);
 #else
        if (pmap->dirbase == 0)
                return(PT_ENTRY_NULL);
 #endif
-       pte = *pmap_pde(pmap, addr);
+       ptp = pmap_pde(pmap, addr);
+       if (ptp == 0)
+               return(PT_ENTRY_NULL);
+       pte = *ptp;
        if ((pte & INTEL_PTE_VALID) == 0)
                return(PT_ENTRY_NULL);
        ptp = (pt_entry_t *)ptetokv(pte);
-- 
2.30.2