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From:   Joerg Roedel <joro@8bytes.org>
To:     x86@kernel.org
Cc:     hpa@zytor.com, Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
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        Dan Williams <dan.j.williams@intel.com>,
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        David Rientjes <rientjes@google.com>,
        Cfir Cohen <cfir@google.com>,
        Erdem Aktas <erdemaktas@google.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Mike Stunes <mstunes@vmware.com>,
        Joerg Roedel <joro@8bytes.org>, Joerg Roedel <jroedel@suse.de>,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org
Subject: [PATCH v3 35/75] x86/head/64: Build k/head64.c with -fno-stack-protector
Date:   Tue, 28 Apr 2020 17:16:45 +0200
Message-Id: <20200428151725.31091-36-joro@8bytes.org>
In-Reply-To: <20200428151725.31091-1-joro@8bytes.org>
References: <20200428151725.31091-1-joro@8bytes.org>
Sender: linux-kernel-owner@vger.kernel.org
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From: Joerg Roedel <jroedel@suse.de>

The code inserted by the stack protector does not work in the early
boot environment because it uses the GS segment, at least with memory
encryption enabled. Make sure the early code is compiled without this
feature enabled.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 arch/x86/kernel/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index ba89cabe5fcf..1192de38fa56 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -35,6 +35,10 @@ ifdef CONFIG_FRAME_POINTER
 OBJECT_FILES_NON_STANDARD_ftrace_$(BITS).o		:= y
 endif
 
+# make sure head64.c is built without stack protector
+nostackp := $(call cc-option, -fno-stack-protector)
+CFLAGS_head64.o		:= $(nostackp)
+
 # If instrumentation of this dir is enabled, boot hangs during first second.
 # Probably could be more selective here, but note that files related to irqs,
 # boot, dumpstack/stacktrace, etc are either non-interesting or can lead to
-- 
2.17.1