[3.16.y-ckt stable] Patch "arm64: errata: Add -mpc-relative-literal-loads to build flags" has been added to the 3.16.y-ckt tree

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    arm64: errata: Add -mpc-relative-literal-loads to build flags

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt25.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

---8<------------------------------------------------------------

>From f026380e278a930b4c71e29886e8263955f43bc7 Mon Sep 17 00:00:00 2001
From: dann frazier <dann.frazier at canonical.com>
Date: Mon, 25 Jan 2016 16:52:16 -0700
Subject: arm64: errata: Add -mpc-relative-literal-loads to build flags

commit 67dfa1751ce71e629aad7c438e1678ad41054677 upstream.

GCC6 (and Linaro's 2015.12 snapshot of GCC5) has a new default that uses
adrp/ldr or adrp/add to address literal pools. When CONFIG_ARM64_ERRATUM_843419
is enabled, modules built with this toolchain fail to load:

  module libahci: unsupported RELA relocation: 275

This patch fixes the problem by passing '-mpc-relative-literal-loads'
to the compiler.

Fixes: df057cc7b4fa ("arm64: errata: add module build workaround for erratum #843419")
BugLink: http://bugs.launchpad.net/bugs/1533009
Acked-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
Suggested-by: Christophe Lyon <christophe.lyon at linaro.org>
Signed-off-by: Dann Frazier <dann.frazier at canonical.com>
Signed-off-by: Will Deacon <will.deacon at arm.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/arm64/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index e82e87e7ff6d..dac811dbe9fa 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -20,6 +20,7 @@ LIBGCC 		:= $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
 KBUILD_DEFCONFIG := defconfig

 KBUILD_CFLAGS	+= -mgeneral-regs-only
+KBUILD_CFLAGS	+= $(call cc-option, -mpc-relative-literal-loads)
 ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
 KBUILD_CPPFLAGS	+= -mbig-endian
 AS		+= -EB