[PATCH] Kbuild: Handle PREEMPT_RT for version string and magic

[Thomas Gleixner <tglx@xxxxxxxxxxxxx>]

Update the build scripts and the version magic to reflect when
CONFIG_PREEMPT_RT is enabled in the same way as CONFIG_PREEMPT is treated.

The resulting version strings:

  Linux m 5.3.0-rc1+ #100 SMP Fri Jul 26 ...
  Linux m 5.3.0-rc1+ #101 SMP PREEMPT Fri Jul 26 ...
  Linux m 5.3.0-rc1+ #102 SMP PREEMPT_RT Fri Jul 26 ...

The module vermagic:

  5.3.0-rc1+ SMP mod_unload modversions 
  5.3.0-rc1+ SMP preempt mod_unload modversions 
  5.3.0-rc1+ SMP preempt_rt mod_unload modversions 

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Cc: Michal Marek <michal.lkml@xxxxxxxxxxx>
Cc: linux-kbuild@xxxxxxxxxxxxxxx
---
 include/linux/vermagic.h |   10 +++++++---
 init/Makefile            |    5 +++--
 scripts/Makefile.modpost |    2 +-
 scripts/mkcompile_h      |    4 +++-
 4 files changed, 14 insertions(+), 7 deletions(-)

--- a/include/linux/vermagic.h
+++ b/include/linux/vermagic.h
@@ -7,10 +7,14 @@
 #else
 #define MODULE_VERMAGIC_SMP ""
 #endif
-#ifdef CONFIG_PREEMPT
-#define MODULE_VERMAGIC_PREEMPT "preempt "
+#ifdef CONFIG_PREEMPTION
+# ifdef CONFIG_PREEMPT
+#  define MODULE_VERMAGIC_PREEMPT "preempt "
+# else
+#  define MODULE_VERMAGIC_PREEMPT "preempt_rt "
+# endif
 #else
-#define MODULE_VERMAGIC_PREEMPT ""
+# define MODULE_VERMAGIC_PREEMPT ""
 #endif
 #ifdef CONFIG_MODULE_UNLOAD
 #define MODULE_VERMAGIC_MODULE_UNLOAD "mod_unload "
--- a/init/Makefile
+++ b/init/Makefile
@@ -33,5 +33,6 @@ mounts-$(CONFIG_BLK_DEV_MD)	+= do_mounts
 silent_chk_compile.h = :
 include/generated/compile.h: FORCE
 	@$($(quiet)chk_compile.h)
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@ \
-	"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)" "$(CC) $(KBUILD_CFLAGS)"
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@	\
+	"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)"	\
+	"$(CONFIG_PREEMPT_RT)" "$(CC) $(KBUILD_CFLAGS)"
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -23,7 +23,7 @@
 #   Version magic (see include/linux/vermagic.h for full details)
 #     - Kernel release
 #     - SMP is CONFIG_SMP
-#     - PREEMPT is CONFIG_PREEMPT
+#     - PREEMPT is CONFIG_PREEMPT[_RT]
 #     - GCC Version
 #   Module info
 #     - Module version (MODULE_VERSION)
--- a/scripts/mkcompile_h
+++ b/scripts/mkcompile_h
@@ -5,7 +5,8 @@ TARGET=$1
 ARCH=$2
 SMP=$3
 PREEMPT=$4
-CC=$5
+PREEMPT_RT=$5
+CC=$6
 
 vecho() { [ "${quiet}" = "silent_" ] || echo "$@" ; }
 
@@ -53,6 +54,7 @@ UTS_VERSION="#$VERSION"
 CONFIG_FLAGS=""
 if [ -n "$SMP" ] ; then CONFIG_FLAGS="SMP"; fi
 if [ -n "$PREEMPT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"; fi
+if [ -n "$PREEMPT_RT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT_RT"; fi
 UTS_VERSION="$UTS_VERSION $CONFIG_FLAGS $TIMESTAMP"
 
 # Truncate to maximum length