SPARC64: SPARSEMEM_VMEMMAP support

[apw@shadowen.org: style fixups]
[apw@shadowen.org: vmemmap sparc64: convert to new config options]
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/sparc64/mm/init.c b/arch/sparc64/mm/init.c
index f0ab9aa..69538d1 100644
--- a/arch/sparc64/mm/init.c
+++ b/arch/sparc64/mm/init.c
@@ -1645,6 +1645,58 @@
 unsigned long _PAGE_CACHE __read_mostly;
 EXPORT_SYMBOL(_PAGE_CACHE);
 
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+
+#define VMEMMAP_CHUNK_SHIFT	22
+#define VMEMMAP_CHUNK		(1UL << VMEMMAP_CHUNK_SHIFT)
+#define VMEMMAP_CHUNK_MASK	~(VMEMMAP_CHUNK - 1UL)
+#define VMEMMAP_ALIGN(x)	(((x)+VMEMMAP_CHUNK-1UL)&VMEMMAP_CHUNK_MASK)
+
+#define VMEMMAP_SIZE	((((1UL << MAX_PHYSADDR_BITS) >> PAGE_SHIFT) * \
+			  sizeof(struct page *)) >> VMEMMAP_CHUNK_SHIFT)
+unsigned long vmemmap_table[VMEMMAP_SIZE];
+
+int __meminit vmemmap_populate(struct page *start, unsigned long nr, int node)
+{
+	unsigned long vstart = (unsigned long) start;
+	unsigned long vend = (unsigned long) (start + nr);
+	unsigned long phys_start = (vstart - VMEMMAP_BASE);
+	unsigned long phys_end = (vend - VMEMMAP_BASE);
+	unsigned long addr = phys_start & VMEMMAP_CHUNK_MASK;
+	unsigned long end = VMEMMAP_ALIGN(phys_end);
+	unsigned long pte_base;
+
+	pte_base = (_PAGE_VALID | _PAGE_SZ4MB_4U |
+		    _PAGE_CP_4U | _PAGE_CV_4U |
+		    _PAGE_P_4U | _PAGE_W_4U);
+	if (tlb_type == hypervisor)
+		pte_base = (_PAGE_VALID | _PAGE_SZ4MB_4V |
+			    _PAGE_CP_4V | _PAGE_CV_4V |
+			    _PAGE_P_4V | _PAGE_W_4V);
+
+	for (; addr < end; addr += VMEMMAP_CHUNK) {
+		unsigned long *vmem_pp =
+			vmemmap_table + (addr >> VMEMMAP_CHUNK_SHIFT);
+		void *block;
+
+		if (!(*vmem_pp & _PAGE_VALID)) {
+			block = vmemmap_alloc_block(1UL << 22, node);
+			if (!block)
+				return -ENOMEM;
+
+			*vmem_pp = pte_base | __pa(block);
+
+			printk(KERN_INFO "[%p-%p] page_structs=%lu "
+			       "node=%d entry=%lu/%lu\n", start, block, nr,
+			       node,
+			       addr >> VMEMMAP_CHUNK_SHIFT,
+			       VMEMMAP_SIZE >> VMEMMAP_CHUNK_SHIFT);
+		}
+	}
+	return 0;
+}
+#endif /* CONFIG_SPARSEMEM_VMEMMAP */
+
 static void prot_init_common(unsigned long page_none,
 			     unsigned long page_shared,
 			     unsigned long page_copy,