x86: map UV chipset space - pagetable

Add boot-time function for creating additional 2MB page table entries for
mapping chipset specific cached/uncached ranges.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Cc: linux-mm@kvack.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 40 insertions, 0 deletions

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 77d129d62c97..57d5eff754c9 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -202,6 +202,46 @@ set_pte_vaddr(unsigned long vaddr, pte_t pteval)
 }
 
 /*
+ * Create large page table mappings for a range of physical addresses.
+ */
+static void __init __init_extra_mapping(unsigned long phys, unsigned long size,
+                                                pgprot_t prot)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pmd_t *pmd;
+
+        BUG_ON((phys & ~PMD_MASK) || (size & ~PMD_MASK));
+        for (; size; phys += PMD_SIZE, size -= PMD_SIZE) {
+                pgd = pgd_offset_k((unsigned long)__va(phys));
+                if (pgd_none(*pgd)) {
+                        pud = (pud_t *) spp_getpage();
+                        set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE |
+                                                _PAGE_USER));
+                }
+                pud = pud_offset(pgd, (unsigned long)__va(phys));
+                if (pud_none(*pud)) {
+                        pmd = (pmd_t *) spp_getpage();
+                        set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE |
+                                                _PAGE_USER));
+                }
+                pmd = pmd_offset(pud, phys);
+                BUG_ON(!pmd_none(*pmd));
+                set_pmd(pmd, __pmd(phys | pgprot_val(prot)));
+        }
+}
+
+void __init init_extra_mapping_wb(unsigned long phys, unsigned long size)
+{
+        __init_extra_mapping(phys, size, PAGE_KERNEL_LARGE);
+}
+
+void __init init_extra_mapping_uc(unsigned long phys, unsigned long size)
+{
+        __init_extra_mapping(phys, size, PAGE_KERNEL_LARGE_NOCACHE);
+}
+
+/*
  * The head.S code sets up the kernel high mapping:
  *
  *   from __START_KERNEL_map to __START_KERNEL_map + size (== _end-_text)