From a980ce352fcd408d30b044455e5f6e959d6258b6 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Fri, 18 Nov 2016 13:07:19 -0800
Subject: x86/build: Build compressed x86 kernels as PIE when
 !CONFIG_RELOCATABLE as well

Since the bootloader may load the compressed x86 kernel at any address,
it should always be built as PIE, not just when CONFIG_RELOCATABLE=y.

Otherwise, linker in binutils 2.27 will optimize GOT load into the
absolute address when building the compressed x86 kernel as a non-PIE
executable.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
[ Small wording changes. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/boot/compressed/Makefile | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

(limited to 'arch/x86/boot')

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 536ccfcc01c6..34d9e15857c3 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -40,8 +40,8 @@ GCOV_PROFILE := n
 UBSAN_SANITIZE :=n
 
 LDFLAGS := -m elf_$(UTS_MACHINE)
-ifeq ($(CONFIG_RELOCATABLE),y)
-# If kernel is relocatable, build compressed kernel as PIE.
+# Compressed kernel should be built as PIE since it may be loaded at any
+# address by the bootloader.
 ifeq ($(CONFIG_X86_32),y)
 LDFLAGS += $(call ld-option, -pie) $(call ld-option, --no-dynamic-linker)
 else
@@ -51,7 +51,6 @@ else
 LDFLAGS += $(shell $(LD) --help 2>&1 | grep -q "\-z noreloc-overflow" \
 	&& echo "-z noreloc-overflow -pie --no-dynamic-linker")
 endif
-endif
 LDFLAGS_vmlinux := -T
 
 hostprogs-y	:= mkpiggy
-- 
cgit v1.2.3