Genericize IA64 virtual memory map population function

Provide a function populate_vmmmap that can be used to populate
the Virtual memory map during bootup. This function is limited
to early boot and it here only supports VMAP_PAGE_SIZE == PAGE_SIZE.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.18-mm3/mm/bootmem.c
===================================================================
--- linux-2.6.18-mm3.orig/mm/bootmem.c	2006-10-04 21:48:59.889553051 -0500
+++ linux-2.6.18-mm3/mm/bootmem.c	2006-10-04 22:18:47.757607451 -0500
@@ -16,6 +16,7 @@
 #include <asm/bug.h>
 #include <asm/io.h>
 #include <asm/processor.h>
+#include <asm/pgalloc.h>
 
 #include "internal.h"
 
@@ -485,3 +486,66 @@ void * __init __alloc_bootmem_low_node(p
 	return __alloc_bootmem_core(pgdat->bdata, size, align, goal,
 				    ARCH_LOW_ADDRESS_LIMIT);
 }
+
+#if defined(CONFIG_VIRTUAL_MEM_MAP) && !defined(ARCH_HAS_POPULATE_VMEMMAP)
+/*
+ * Generic VMMAP populate function. This function is only useful
+ * at boot time. In order to populate more segments of the
+ * virtual memory map later (memory hotplug) another function would need
+ * to be supplied.
+ *
+ * This function only supports the case that VMAP_PAGE_SIZE == PAGE_SIZE
+ * and is suitable to share the page table with VMALLOC which supports the
+ * same page size.
+ *
+ * Note that using regular pages for mapping the virtual memory map
+ * may cause TLB pressure on architectures with small page size (4k?).
+ * If an architecture has a small page size but also allows higher
+ * page sizes then arch code should define its own populate_virtual_memmap()
+ * function and support the larger page size.
+ */
+
+#if VMEMMAP_PAGE_SIZE != PAGE_SIZE
+#error "Generic populate_virtual_memmap() function only supports PAGE_SIZE!"
+#endif
+
+void __init populate_virtual_memmap(int nid, unsigned long start_pfn,
+					 unsigned long end_pfn)
+{
+	unsigned long addr, start, end;
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+	struct pglist_data *pgdat = NODE_DATA(nid);
+
+	start = (unsigned long)&mem_map[start_pfn] & ~(VMEMMAP_PAGE_SIZE - 1);
+	end   = ALIGN((unsigned long)&mem_map[end_pfn], VMEMMAP_PAGE_SIZE);
+
+	for (addr = start; addr < end; addr += VMEMMAP_PAGE_SIZE) {
+
+		pgd = pgd_offset_k(addr);
+		if (pgd_none(*pgd))
+			pgd_populate(&init_mm, pgd,
+				alloc_bootmem_pages_node(pgdat, PAGE_SIZE));
+
+		pud = pud_offset(pgd, addr);
+		if (pud_none(*pud))
+			pud_populate(&init_mm, pud,
+				alloc_bootmem_pages_node(pgdat, PAGE_SIZE));
+
+		pmd = pmd_offset(pud, addr);
+		if (pmd_none(*pmd))
+			pmd_populate_kernel(&init_mm, pmd,
+				alloc_bootmem_pages_node(pgdat, PAGE_SIZE));
+
+		pte = pte_offset_kernel(pmd, addr);
+		if (pte_none(*pte))
+			set_pte(pte, pfn_pte(__pa(
+				alloc_bootmem_pages_node(pgdat,
+				VMEMMAP_PAGE_SIZE)) >> PAGE_SHIFT,
+				PAGE_KERNEL));
+	}
+}
+#endif
+
Index: linux-2.6.18-mm3/arch/ia64/mm/init.c
===================================================================
--- linux-2.6.18-mm3.orig/arch/ia64/mm/init.c	2006-10-04 21:51:09.545114056 -0500
+++ linux-2.6.18-mm3/arch/ia64/mm/init.c	2006-10-04 22:02:33.375776717 -0500
@@ -472,39 +472,10 @@ retry_pte:
 int __init
 create_mem_map_page_table (u64 start, u64 end, void *arg)
 {
-	unsigned long address, start_page, end_page;
-	struct page *map_start, *map_end;
-	int node;
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
+	populate_virtual_memmap(paddr_to_nid(__pa(start)),
+		__pa(start) >> PAGE_SHIFT,
+		__pa(end) >> PAGE_SHIFT);
 
-	map_start = mem_map + (__pa(start) >> PAGE_SHIFT);
-	map_end   = mem_map + (__pa(end) >> PAGE_SHIFT);
-
-	start_page = (unsigned long) map_start & PAGE_MASK;
-	end_page = PAGE_ALIGN((unsigned long) map_end);
-	node = paddr_to_nid(__pa(start));
-
-	for (address = start_page; address < end_page; address += PAGE_SIZE) {
-		pgd = pgd_offset_k(address);
-		if (pgd_none(*pgd))
-			pgd_populate(&init_mm, pgd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
-		pud = pud_offset(pgd, address);
-
-		if (pud_none(*pud))
-			pud_populate(&init_mm, pud, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
-		pmd = pmd_offset(pud, address);
-
-		if (pmd_none(*pmd))
-			pmd_populate_kernel(&init_mm, pmd, alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE));
-		pte = pte_offset_kernel(pmd, address);
-
-		if (pte_none(*pte))
-			set_pte(pte, pfn_pte(__pa(alloc_bootmem_pages_node(NODE_DATA(node), PAGE_SIZE)) >> PAGE_SHIFT,
-					     PAGE_KERNEL));
-	}
 	return 0;
 }
 
Index: linux-2.6.18-mm3/include/linux/bootmem.h
===================================================================
--- linux-2.6.18-mm3.orig/include/linux/bootmem.h	2006-10-04 21:48:59.912992544 -0500
+++ linux-2.6.18-mm3/include/linux/bootmem.h	2006-10-04 22:02:37.930852056 -0500
@@ -132,5 +132,6 @@ extern void *alloc_large_system_hash(con
 #endif
 extern int hashdist;		/* Distribute hashes across NUMA nodes? */
 
-
+extern void populate_virtual_memmap(int nid, unsigned long start_pfn,
+					unsigned long end_pfn);
 #endif /* _LINUX_BOOTMEM_H */