diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 7a9886f98b0c..a5091c034747 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -188,15 +188,20 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 	pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node);
 
 	for (; start < end; start += page_size) {
-		void *p;
+		void *p = NULL;
 		int rc;
 
 		if (vmemmap_populated(start, page_size))
 			continue;
 
+		/*
+		 * Allocate from the altmap first if we have one. This may
+		 * fail due to alignment issues when using 16MB hugepages, so
+		 * fall back to system memory if the altmap allocation fail.
+		 */
 		if (altmap)
 			p = altmap_alloc_block_buf(page_size, altmap);
-		else
+		if (!p)
 			p = vmemmap_alloc_block_buf(page_size, node);
 		if (!p)
 			return -ENOMEM;
@@ -255,8 +260,15 @@ void __ref vmemmap_free(unsigned long start, unsigned long end,
 {
 	unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
 	unsigned long page_order = get_order(page_size);
+	unsigned long alt_start = ~0, alt_end = ~0;
+	unsigned long base_pfn;
 
 	start = _ALIGN_DOWN(start, page_size);
+	if (altmap) {
+		alt_start = altmap->base_pfn;
+		alt_end = altmap->base_pfn + altmap->reserve +
+			  altmap->free + altmap->alloc + altmap->align;
+	}
 
 	pr_debug("vmemmap_free %lx...%lx\n", start, end);
 
@@ -280,8 +292,9 @@ void __ref vmemmap_free(unsigned long start, unsigned long end,
 		page = pfn_to_page(addr >> PAGE_SHIFT);
 		section_base = pfn_to_page(vmemmap_section_start(start));
 		nr_pages = 1 << page_order;
+		base_pfn = PHYS_PFN(addr);
 
-		if (altmap) {
+		if (base_pfn >= alt_start && base_pfn < alt_end) {
 			vmem_altmap_free(altmap, nr_pages);
 		} else if (PageReserved(page)) {
 			/* allocated from bootmem */