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authorKees Cook <kees@kernel.org>2025-05-03 11:46:18 -0700
committerKees Cook <kees@kernel.org>2025-05-08 09:42:06 -0700
commit0cecd37daef3d57e6656c0023978d5ec2d7409c1 (patch)
tree497cc620941750eb1efaa602b40e1dbcc35c6ef1 /scripts
parent5e88c48cb4bcbd0ea683373a106268933bb4edd2 (diff)
gcc-plugins: Force full rebuild when plugins change
There was no dependency between the plugins changing and the rest of the kernel being built. This could cause strange behaviors as instrumentation could vary between targets depending on when they were built. Generate a new header file, gcc-plugins.h, any time the GCC plugins change. Include the header file in compiler-version.h when its associated feature name, GCC_PLUGINS, is defined. This will be picked up by fixdep and force rebuilds where needed. Add a generic "touch" kbuild command, which will be used again in a following patch. Add a "normalize_path" string helper to make the "TOUCH" output less ugly. Link: https://lore.kernel.org/r/20250503184623.2572355-1-kees@kernel.org Tested-by: Nicolas Schier <n.schier@avm.de> Reviewed-by: Nicolas Schier <n.schier@avm.de> Signed-off-by: Kees Cook <kees@kernel.org>
Diffstat (limited to 'scripts')
-rw-r--r--scripts/Makefile.gcc-plugins2
-rw-r--r--scripts/Makefile.lib18
-rw-r--r--scripts/gcc-plugins/Makefile4
3 files changed, 23 insertions, 1 deletions
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index 5b8a8378ca8ad..e50dc931be499 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins
@@ -38,7 +38,7 @@ export DISABLE_STACKLEAK_PLUGIN
# All the plugin CFLAGS are collected here in case a build target needs to
# filter them out of the KBUILD_CFLAGS.
-GCC_PLUGINS_CFLAGS := $(strip $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) $(gcc-plugin-cflags-y))
+GCC_PLUGINS_CFLAGS := $(strip $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) $(gcc-plugin-cflags-y)) -DGCC_PLUGINS
export GCC_PLUGINS_CFLAGS
# Add the flags to the build!
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 2fe73cda0bddb..6fc2a82ee3bba 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -296,6 +296,19 @@ $(foreach m, $1, \
$(addprefix $(obj)/, $(call suffix-search, $(patsubst $(obj)/%,%,$m), $2, $3))))
endef
+# Remove ".." and "." from a path, without using "realpath"
+# Usage:
+# $(call normalize_path,path/to/../file)
+define normalize_path
+$(strip $(eval elements :=) \
+$(foreach elem,$(subst /, ,$1), \
+ $(if $(filter-out .,$(elem)), \
+ $(if $(filter ..,$(elem)), \
+ $(eval elements := $(wordlist 2,$(words $(elements)),x $(elements))), \
+ $(eval elements := $(elements) $(elem))))) \
+$(subst $(space),/,$(elements)))
+endef
+
# Build commands
# ===========================================================================
# These are shared by some Makefile.* files.
@@ -343,6 +356,11 @@ quiet_cmd_copy = COPY $@
$(obj)/%: $(src)/%_shipped
$(call cmd,copy)
+# Touch a file
+# ===========================================================================
+quiet_cmd_touch = TOUCH $(call normalize_path,$@)
+ cmd_touch = touch $@
+
# Commands useful for building a boot image
# ===========================================================================
#
diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile
index 320afd3cf8e82..05b14aba41efc 100644
--- a/scripts/gcc-plugins/Makefile
+++ b/scripts/gcc-plugins/Makefile
@@ -66,3 +66,7 @@ quiet_cmd_plugin_cxx_o_c = HOSTCXX $@
$(plugin-objs): $(obj)/%.o: $(src)/%.c FORCE
$(call if_changed_dep,plugin_cxx_o_c)
+
+$(obj)/../../include/generated/gcc-plugins.h: $(plugin-single) $(plugin-multi) FORCE
+ $(call if_changed,touch)
+always-y += ../../include/generated/gcc-plugins.h