Patch "x86/build/64: Force the linker to use 2MB page size" has been added to the 4.9-stable tree

Patch "x86/build/64: Force the linker to use 2MB page size" has been added to the 4.9-stable tree

[gregkh]

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;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-4.9 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_8twdpTyAP2DhONOCeaTOsniJLoppzhoNptL8xzA@mail.gmail.com
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