This is a note to let you know that I've just added the patch titled

x86/build/64: Force the linker to use 2MB page size

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: x86-build-64-force-the-linker-to-use-2mb-page-size.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From e3d03598e8ae7d195af5d3d049596dec336f569f Mon Sep 17 00:00:00 2001

From: "H.J. Lu" hjl.tools@gmail.com Date: Mon, 19 Mar 2018 13:57:46 -0700 Subject: x86/build/64: Force the linker to use 2MB page size

From: H.J. Lu hjl.tools@gmail.com

commit e3d03598e8ae7d195af5d3d049596dec336f569f upstream.

Binutils 2.31 will enable -z separate-code by default for x86 to avoid mixing code pages with data to improve cache performance as well as security. To reduce x86-64 executable and shared object sizes, the maximum page size is reduced from 2MB to 4KB. But x86-64 kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to linker to force 2MB page size regardless of the default page size used by linker.

Tested with Linux kernel 4.15.6 on x86-64.

Signed-off-by: H.J. Lu hjl.tools@gmail.com Cc: Andy Shevchenko andy.shevchenko@gmail.com Cc: Eric Biederman ebiederm@xmission.com Cc: H. Peter Anvin hpa@zytor.com Cc: Juergen Gross jgross@suse.com Cc: Kees Cook keescook@chromium.org Cc: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/CAMe9rOp4_%3D_8twdpTyAP2DhONOCeaTOsniJLoppzhoNptL8x... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/x86/Makefile | 9 +++++++++ 1 file changed, 9 insertions(+)

--- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -172,6 +172,15 @@ KBUILD_CFLAGS += $(cfi) $(cfi-sigframe)

LDFLAGS := -m elf_$(UTS_MACHINE)

+# +# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to +# the linker to force 2MB page size regardless of the default page size used +# by the linker. +# +ifdef CONFIG_X86_64 +LDFLAGS += $(call ld-option, -z max-page-size=0x200000) +endif + # Speed up the build KBUILD_CFLAGS += -pipe # Workaround for a gcc prelease that unfortunately was shipped in a suse release

Patches currently in stable-queue which might be from hjl.tools@gmail.com are

queue-4.9/x86-boot-64-verify-alignment-of-the-load-segment.patch queue-4.9/x86-build-64-force-the-linker-to-use-2mb-page-size.patch