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 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary 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-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From e3d03598e8ae7d195af5d3d049596dec336f569f Mon Sep 17 00:00:00 2001 From: "H.J. Lu" <hjl.tools@xxxxxxxxx> 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@xxxxxxxxx> 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@xxxxxxxxx> Cc: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Juergen Gross <jgross@xxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/CAMe9rOp4_%3D_8twdpTyAP2DhONOCeaTOsniJLoppzhoNptL8xzA@xxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/Makefile | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -179,6 +179,15 @@ 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@xxxxxxxxx are queue-4.4/x86-boot-64-verify-alignment-of-the-load-segment.patch queue-4.4/x86-build-64-force-the-linker-to-use-2mb-page-size.patch