sched/preempt: Tell about PREEMPT_DYNAMIC on kernel headers

Displaying "PREEMPT" on kernel headers when CONFIG_PREEMPT_DYNAMIC=y
can be misleading for anybody involved in remote debugging because it
is then not guaranteed that there is an actual preemption behaviour. It
depends on default Kconfig or boot defined choices.

Therefore, tell about PREEMPT_DYNAMIC on static kernel headers and leave
the search for the actual preemption behaviour to browsing dmesg.

Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220217111240.GA742892@lothringen

diff --git a/init/Makefile b/init/Makefile
index 06326e30438407ee98c2276387230ad7d10e1a94..d82623d7fc8e8c89d6442dfa15feac384a9ec2c4 100644 (file)
--- a/init/Makefile
+++ b/init/Makefile
@@ -31,7 +31,8 @@ quiet_cmd_compile.h = CHK     $@
       cmd_compile.h = \
        $(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@       \
        "$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT_BUILD)"      \
-       "$(CONFIG_PREEMPT_RT)" "$(CONFIG_CC_VERSION_TEXT)" "$(LD)"
+       "$(CONFIG_PREEMPT_DYNAMIC)" "$(CONFIG_PREEMPT_RT)" \
+       "$(CONFIG_CC_VERSION_TEXT)" "$(LD)"
 
 include/generated/compile.h: FORCE
        $(call cmd,compile.h)

diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h
index 6a2a04d92f42fd8e5dd3d10f900ccb971214ccd0..ca40a5258c8778214c93f32ae241b1274d0cceaf 100755 (executable)
--- a/scripts/mkcompile_h
+++ b/scripts/mkcompile_h
@@ -5,9 +5,10 @@ TARGET=$1
 ARCH=$2
 SMP=$3
 PREEMPT=$4
-PREEMPT_RT=$5
-CC_VERSION="$6"
-LD=$7
+PREEMPT_DYNAMIC=$5
+PREEMPT_RT=$6
+CC_VERSION="$7"
+LD=$8
 
 # Do not expand names
 set -f
@@ -41,8 +42,14 @@ fi
 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
+
+if [ -n "$PREEMPT_RT" ] ; then
+       CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT_RT"
+elif [ -n "$PREEMPT_DYNAMIC" ] ; then
+       CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT_DYNAMIC"
+elif [ -n "$PREEMPT" ] ; then
+       CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"
+fi
 
 # Truncate to maximum length
 UTS_LEN=64