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>

arch/x86/mm/init_64.c

@@ -201,6 +201,46 @@ set_pte_vaddr(unsigned long vaddr, pte_t pteval)
 	set_pte_vaddr_pud(pud_page, vaddr, 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:
  *

include/asm-x86/page_64.h

@@ -91,6 +91,10 @@ extern unsigned long init_memory_mapping(unsigned long start,
 					 unsigned long end);
 
 extern void initmem_init(unsigned long start_pfn, unsigned long end_pfn);
+
+extern void init_extra_mapping_uc(unsigned long phys, unsigned long size);
+extern void init_extra_mapping_wb(unsigned long phys, unsigned long size);
+
 #endif	/* !__ASSEMBLY__ */
 
 #ifdef CONFIG_FLATMEM

include/asm-x86/pgtable.h

@@ -91,6 +91,7 @@
 #define __PAGE_KERNEL_VSYSCALL		(__PAGE_KERNEL_RX | _PAGE_USER)
 #define __PAGE_KERNEL_VSYSCALL_NOCACHE	(__PAGE_KERNEL_VSYSCALL | _PAGE_PCD | _PAGE_PWT)
 #define __PAGE_KERNEL_LARGE		(__PAGE_KERNEL | _PAGE_PSE)
+#define __PAGE_KERNEL_LARGE_NOCACHE	(__PAGE_KERNEL | _PAGE_CACHE_UC | _PAGE_PSE)
 #define __PAGE_KERNEL_LARGE_EXEC	(__PAGE_KERNEL_EXEC | _PAGE_PSE)
 
 #define PAGE_KERNEL			__pgprot(__PAGE_KERNEL)
@@ -102,6 +103,7 @@
 #define PAGE_KERNEL_UC_MINUS		__pgprot(__PAGE_KERNEL_UC_MINUS)
 #define PAGE_KERNEL_EXEC_NOCACHE	__pgprot(__PAGE_KERNEL_EXEC_NOCACHE)
 #define PAGE_KERNEL_LARGE		__pgprot(__PAGE_KERNEL_LARGE)
+#define PAGE_KERNEL_LARGE_NOCACHE	__pgprot(__PAGE_KERNEL_LARGE_NOCACHE)
 #define PAGE_KERNEL_LARGE_EXEC		__pgprot(__PAGE_KERNEL_LARGE_EXEC)
 #define PAGE_KERNEL_VSYSCALL		__pgprot(__PAGE_KERNEL_VSYSCALL)
 #define PAGE_KERNEL_VSYSCALL_NOCACHE	__pgprot(__PAGE_KERNEL_VSYSCALL_NOCACHE)