[PATCH] xen/x86: prevent addition of .note.gnu.property if livepatch is enabled

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

GNU assembly that supports such feature will unconditionally add a
.note.gnu.property section to object files.  The content of that section can
change depending on the generated instructions.  The current logic in
livepatch-build-tools doesn't know how to deal with such section changing
as a result of applying a patch and rebuilding.

Since .note.gnu.property is not consumed by the Xen build, suppress its
addition when livepatch support is enabled.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/arch.mk | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/xen/arch/x86/arch.mk b/xen/arch/x86/arch.mk
index 1460ecf30b9a..1ded012d9f5b 100644
--- a/xen/arch/x86/arch.mk
+++ b/xen/arch/x86/arch.mk
@@ -26,6 +26,12 @@ $(call as-option-add,CFLAGS,CC,"invpcid 
(%rax)$(comma)%rax",-DHAVE_AS_INVPCID)
 $(call as-option-add,CFLAGS,CC,"movdiri %rax$(comma)(%rax)",-DHAVE_AS_MOVDIR)
 $(call as-option-add,CFLAGS,CC,"enqcmd (%rax)$(comma)%rax",-DHAVE_AS_ENQCMD)
 
+# Disable the addition of a .note.gnu.property section to object files when
+# livepatch support is enabled.  The contents of that section can change
+# depending on the instructions used, and livepatch-build-tools doesn't know
+# how to deal with such changes.
+$(call 
cc-option-add,CFLAGS-$(CONFIG_LIVEPATCH),CC,-Wa$$(comma)-mx86-used-note=no)
+
 # Check to see whether the assmbler supports the .nop directive.
 $(call as-option-add,CFLAGS,CC,\
     ".L1: .L2: .nops (.L2 - .L1)$(comma)9",-DHAVE_AS_NOPS_DIRECTIVE)
-- 
2.46.0