From 337965ad71520c758a2cae03705a29afb1c56883 Mon Sep 17 00:00:00 2001
From: Joe Lawrence <joe.lawrence@redhat.com>
Date: Wed, 8 Feb 2017 17:02:12 -0500
Subject: [PATCH] kpatch-build: consider CONFIG_PARAVIRT optional

CONFIG_PARAVIRT is not required for building kpatch patch modules.  The
sizeof paravirt_patch_site struct was only needed to create
.parainstructions sections as part of create-diff-object.  As long as
the original objects were built without such sections then
this kernel option (and struct handling) can be considered optional.
---
 kpatch-build/kpatch-build | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/kpatch-build/kpatch-build b/kpatch-build/kpatch-build
index cd55473..46dfb50 100755
--- a/kpatch-build/kpatch-build
+++ b/kpatch-build/kpatch-build
@@ -505,6 +505,13 @@ else
 	KBUILD_EXTRA_SYMBOLS="$SYMVERSFILE"
 fi
 
+# optional kernel configs: CONFIG_PARAVIRT
+if grep "CONFIG_PARAVIRT=y" "$OBJDIR/.config" > /dev/null; then
+	CONFIG_PARAVIRT=1
+else
+	CONFIG_PARAVIRT=0
+fi
+
 # unsupported kernel option checking: CONFIG_DEBUG_INFO_SPLIT
 grep -q "CONFIG_DEBUG_INFO_SPLIT=y" "$OBJDIR/.config" && die "kernel option 'CONFIG_DEBUG_INFO_SPLIT' not supported"
 
@@ -516,8 +523,9 @@ cp -LR "$DATADIR/patch" "$TEMPDIR" || die
 export KCFLAGS="-I$DATADIR/patch -ffunction-sections -fdata-sections"
 
 echo "Reading special section data"
+[[ $CONFIG_PARAVIRT -eq 0 ]] && AWK_OPTIONS="-vskip_p=1"
 SPECIAL_VARS=$(readelf -wi "$VMLINUX" |
-	       gawk --non-decimal-data '
+	       gawk --non-decimal-data $AWK_OPTIONS '
 	       BEGIN { a = b = p = e = 0 }
 
 	       # Set state if name matches
@@ -539,14 +547,15 @@ SPECIAL_VARS=$(readelf -wi "$VMLINUX" |
 	       e == 1 {printf("export EX_STRUCT_SIZE=%d\n", $4); e = 2}
 
 	       # Bail out once we have everything
-	       a == 2 && b == 2 && p == 2 && e == 2 {exit}')
+	       a == 2 && b == 2 && (p == 2 || skip_p) && e == 2 {exit}')
 
 [[ -n $SPECIAL_VARS ]] && eval "$SPECIAL_VARS"
 
-if [[ -z $ALT_STRUCT_SIZE ]] || [[ -z $BUG_STRUCT_SIZE ]] ||
-   [[ -z $PARA_STRUCT_SIZE ]] || [[ -z $EX_STRUCT_SIZE ]]; then
-	die "can't find special struct size"
-fi
+[[ -z $ALT_STRUCT_SIZE ]] && die "can't find special struct alt_instr size"
+[[ -z $BUG_STRUCT_SIZE ]] && die "can't find special struct bug_entry size"
+[[ -z $EX_STRUCT_SIZE ]]  && die "can't find special struct paravirt_patch_site size"
+[[ -z $PARA_STRUCT_SIZE && $CONFIG_PARAVIRT -ne 0 ]] && die "can't find special struct paravirt_patch_site size"
+
 for i in $ALT_STRUCT_SIZE $BUG_STRUCT_SIZE $PARA_STRUCT_SIZE $EX_STRUCT_SIZE; do
 	if [[ ! $i -gt 0 ]] || [[ ! $i -le 16 ]]; then
 		die "invalid special struct size $i"