[PATCH v4 08/27] x86/mm: make register_page_bootmem_memmap handle PTE mappings

[Frank van der Linden]

register_page_bootmem_memmap expects that vmemmap pages handed
to it are PMD-mapped, and that the number of pages to call
get_page_bootmem on is PMD-aligned.

This is currently a correct assumption, but will no longer be
true once pre-HVO of hugetlb pages is implemented.

Make it handle PTE-mapped vmemmap pages and a nr_pages argument
that is not necessarily PAGES_PER_SECTION.

Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Frank van der Linden <fvdl@xxxxxxxxxx>
---
 arch/x86/mm/init_64.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 01ea7c6df303..6e8e4ef5312a 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1599,11 +1599,14 @@ void register_page_bootmem_memmap(unsigned long section_nr,
 		}
 		get_page_bootmem(section_nr, pud_page(*pud), MIX_SECTION_INFO);
 
-		if (!boot_cpu_has(X86_FEATURE_PSE)) {
+		pmd = pmd_offset(pud, addr);
+		if (pmd_none(*pmd)) {
+			next = (addr + PAGE_SIZE) & PAGE_MASK;
+			continue;
+		}
+
+		if (!boot_cpu_has(X86_FEATURE_PSE) || !pmd_leaf(*pmd)) {
 			next = (addr + PAGE_SIZE) & PAGE_MASK;
-			pmd = pmd_offset(pud, addr);
-			if (pmd_none(*pmd))
-				continue;
 			get_page_bootmem(section_nr, pmd_page(*pmd),
 					 MIX_SECTION_INFO);
 
@@ -1614,12 +1617,7 @@ void register_page_bootmem_memmap(unsigned long section_nr,
 					 SECTION_INFO);
 		} else {
 			next = pmd_addr_end(addr, end);
-
-			pmd = pmd_offset(pud, addr);
-			if (pmd_none(*pmd))
-				continue;
-
-			nr_pmd_pages = 1 << get_order(PMD_SIZE);
+			nr_pmd_pages = (next - addr) >> PAGE_SHIFT;
 			page = pmd_page(*pmd);
 			while (nr_pmd_pages--)
 				get_page_bootmem(section_nr, page++,
-- 
2.48.1.601.g30ceb7b040-goog