From 3a218961b16f1f4feb1147f56338faf1ac8f5703 Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Tue, 12 May 2020 19:18:43 +0100 Subject: [PATCH] x86/build: Unilaterally disable -fcf-protection Xen doesn't support CET-IBT yet. At a minimum, logic is required to enable it for supervisor use, but the livepatch functionality needs to learn not to overwrite ENDBR64 instructions. Furthermore, Ubuntu enables -fcf-protection by default, along with a buggy version of GCC-9 which objects to it in combination with -mindirect-branch=thunk-extern (Fixed in GCC 10, 9.4). Various objects (Xen boot path, Rombios 32 stubs) require .text to be at the beginning of the object. These paths explode when .note.gnu.properties gets put ahead of .text and we end up executing the notes data. Disable -fcf-protection for all embedded objects. Reported-by: Jason Andryuk Signed-off-by: Andrew Cooper Reviewed-by: Jason Andryuk Reviewed-by: Jan Beulich --- Config.mk | 1 + 1 file changed, 1 insertion(+) diff --git a/Config.mk b/Config.mk index b0f16680f3..7d556aed30 100644 --- a/Config.mk +++ b/Config.mk @@ -205,6 +205,7 @@ APPEND_CFLAGS += $(foreach i, $(APPEND_INCLUDES), -I$(i)) EMBEDDED_EXTRA_CFLAGS := -nopie -fno-stack-protector -fno-stack-protector-all EMBEDDED_EXTRA_CFLAGS += -fno-exceptions -fno-asynchronous-unwind-tables +EMBEDDED_EXTRA_CFLAGS += -fcf-protection=none XEN_EXTFILES_URL ?= http://xenbits.xen.org/xen-extfiles # All the files at that location were downloaded from elsewhere on -- 2.30.2