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Patch "x86/build/64: Force the linker to use 2MB page size" has been added to the 4.14-stable tree

PATCH [email protected] 1 participant 1 message Mar 26, 2018

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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 4.14-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-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From e3d03598e8ae7d195af5d3d049596dec336f569f Mon Sep 17 00:00:00 2001

From: "H.J. Lu" <[email protected]>
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 <[email protected]>

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 <[email protected]>
Cc Andy Shevchenko <[email protected]>
Cc Eric Biederman <[email protected]>
Cc H. Peter Anvin <[email protected]>
Cc Juergen Gross <[email protected]>
Cc Kees Cook <[email protected]>
Cc Kirill A. Shutemov <[email protected]>
Cc Linus Torvalds <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Thomas Gleixner <[email protected]>
Link http://lkml.kernel.org/r/CAMe9rOp4_%[email protected] open here
Signed-off-by Ingo Molnar <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 arch/x86/Makefile |    9 +++++++++
 1 file changed, 9 insertions(+)
arch/x86/Makefile +9 -0
@@ -223,6 +223,15 @@ 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 [email protected] are

queue-4.14/x86-boot-64-verify-alignment-of-the-load-segment.patch queue-4.14/x86-build-64-force-the-linker-to-use-2mb-page-size.patch