EFI fix for v4.9 queue

Folks, please pull the following fix for the v4.9 EFI queue sat in tip/efi/core.

The following changes since commit 5465fe0fc3316f7cdda66732a7986f4ebe76d949:

Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into efi/core (2016-09-13 20:21:55 +0200)

are available in the git repository at:

git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi.git tags/efi-next

for you to fetch changes up to 92dc33501bfba74655dbf3ec63ea82d040fd6d58:

x86/efi: Round EFI memmap reservations to EFI_PAGE_SIZE (2016-09-20 15:43:31 +0100)

----------------------------------------------------------------
* Fix a boot crash reported by Mike Galbraith and Mike Krinkin. The new EFI memory map reservation code didn't align reservations to EFI_PAGE_SIZE boundaries causing bogus regions to be inserted into the global EFI memory map - Matt Fleming

----------------------------------------------------------------
Matt Fleming (1):
x86/efi: Round EFI memmap reservations to EFI_PAGE_SIZE

 arch/x86/platform/efi/quirks.c |  6 +++++-
 drivers/firmware/efi/memmap.c  | 11 +++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

Mike Galbraith reported that his machine started rebooting during boot after,

commit 8e80632fb23f ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()")

The ESRT table on his machine is 56 bytes and at no point in the efi_arch_mem_reserve() call path is that size rounded up to EFI_PAGE_SIZE, nor is the start address on an EFI_PAGE_SIZE boundary.

Since the EFI memory map only deals with whole pages, inserting an EFI memory region with 56 bytes results in a new entry covering zero pages, and completely screws up the calculations for the old regions that were trimmed.

Round all sizes upwards, and start addresses downwards, to the nearest EFI_PAGE_SIZE boundary.

Additionally, efi_memmap_insert() expects the mem::range::end value to be one less than the end address for the region.

---
 arch/x86/platform/efi/quirks.c |  6 +++++-
 drivers/firmware/efi/memmap.c  | 11 +++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

index f14b7a9da24b..10aca63a50d7 100644
@@ -201,8 +201,12 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
 		return;
 	}
 
+	size += addr % EFI_PAGE_SIZE;
+	size = round_up(size, EFI_PAGE_SIZE);
+	addr = round_down(addr, EFI_PAGE_SIZE);
+
 	mr.range.start = addr;
-	mr.range.end = addr + size;
+	mr.range.end = addr + size - 1;
 	mr.attribute = md.attribute | EFI_MEMORY_RUNTIME;
 
 	num_entries = efi_memmap_split_count(&md, &mr.range);

index cd96086fd851..f03ddecd232b 100644
@@ -225,6 +225,17 @@ void __init efi_memmap_insert(struct efi_memory_map *old_memmap, void *buf,
 	m_end = mem->range.end;
 	m_attr = mem->attribute;
 
+	/*
+	 * The EFI memory map deals with regions in EFI_PAGE_SIZE
+	 * units. Ensure that the region described by 'mem' is aligned
+	 * correctly.
+	 */
+	if (!IS_ALIGNED(m_start, EFI_PAGE_SIZE) ||
+	    !IS_ALIGNED(m_end + 1, EFI_PAGE_SIZE)) {
+		WARN_ON(1);
+		return;
+	}
+
 	for (old = old_memmap->map, new = buf;
 	     old < old_memmap->map_end;
 	     old += old_memmap->desc_size, new += old_memmap->desc_size) {

2.9.3

Pulled into tip:efi/core, thanks a lot Matt!

Ingo