ppc64: SPARSEMEM_VMEMMAP support
Enable virtual memmap support for SPARSEMEM on PPC64 systems. Slice a 16th
off the end of the linear mapping space and use that to hold the vmemmap.
Uses the same size mapping as uses in the linear 1:1 kernel mapping.
[pbadari@gmail.com: fix warning]
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index fa90f65..29ed495 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -183,3 +183,70 @@
zero_ctor);
}
}
+
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+/*
+ * Given an address within the vmemmap, determine the pfn of the page that
+ * represents the start of the section it is within. Note that we have to
+ * do this by hand as the proffered address may not be correctly aligned.
+ * Subtraction of non-aligned pointers produces undefined results.
+ */
+unsigned long __meminit vmemmap_section_start(unsigned long page)
+{
+ unsigned long offset = page - ((unsigned long)(vmemmap));
+
+ /* Return the pfn of the start of the section. */
+ return (offset / sizeof(struct page)) & PAGE_SECTION_MASK;
+}
+
+/*
+ * Check if this vmemmap page is already initialised. If any section
+ * which overlaps this vmemmap page is initialised then this page is
+ * initialised already.
+ */
+int __meminit vmemmap_populated(unsigned long start, int page_size)
+{
+ unsigned long end = start + page_size;
+
+ for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page)))
+ if (pfn_valid(vmemmap_section_start(start)))
+ return 1;
+
+ return 0;
+}
+
+int __meminit vmemmap_populate(struct page *start_page,
+ unsigned long nr_pages, int node)
+{
+ unsigned long mode_rw;
+ unsigned long start = (unsigned long)start_page;
+ unsigned long end = (unsigned long)(start_page + nr_pages);
+ unsigned long page_size = 1 << mmu_psize_defs[mmu_linear_psize].shift;
+
+ mode_rw = _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_COHERENT | PP_RWXX;
+
+ /* Align to the page size of the linear mapping. */
+ start = _ALIGN_DOWN(start, page_size);
+
+ for (; start < end; start += page_size) {
+ int mapped;
+ void *p;
+
+ if (vmemmap_populated(start, page_size))
+ continue;
+
+ p = vmemmap_alloc_block(page_size, node);
+ if (!p)
+ return -ENOMEM;
+
+ printk(KERN_WARNING "vmemmap %08lx allocated at %p, "
+ "physical %p.\n", start, p, __pa(p));
+
+ mapped = htab_bolt_mapping(start, start + page_size,
+ __pa(p), mode_rw, mmu_linear_psize);
+ BUG_ON(mapped < 0);
+ }
+
+ return 0;
+}
+#endif