Merge tag 'gcc-plugin-cleanup-v4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull gcc plugin cleanups from Kees Cook:

 - Kconfig and Makefile clean-ups (Masahiro Yamada, Kees Cook)

 - gcc-common.h definition clean-ups (Alexander Popov)

* tag 'gcc-plugin-cleanup-v4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  gcc-plugins: Clean up the cgraph_create_edge* macros
  gcc-plugins: Regularize Makefile.gcc-plugins
  gcc-plugins: split out Kconfig entries to scripts/gcc-plugins/Kconfig
  gcc-plugins: remove unused GCC_PLUGIN_SUBDIR

4 files changed, 182 insertions, 28 deletions

diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index c961b9a65d11..0a482f341576 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins
@@ -1,33 +1,44 @@
 # SPDX-License-Identifier: GPL-2.0
+
 gcc-plugin-$(CONFIG_GCC_PLUGIN_CYC_COMPLEXITY)	+= cyc_complexity_plugin.so
 
 gcc-plugin-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY)	+= latent_entropy_plugin.so
-gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY)	+= -DLATENT_ENTROPY_PLUGIN
+gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY)		\
+		+= -DLATENT_ENTROPY_PLUGIN
 ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
-    DISABLE_LATENT_ENTROPY_PLUGIN			+= -fplugin-arg-latent_entropy_plugin-disable
+    DISABLE_LATENT_ENTROPY_PLUGIN += -fplugin-arg-latent_entropy_plugin-disable
 endif
+export DISABLE_LATENT_ENTROPY_PLUGIN
 
 gcc-plugin-$(CONFIG_GCC_PLUGIN_SANCOV)		+= sancov_plugin.so
+
 gcc-plugin-$(CONFIG_GCC_PLUGIN_STRUCTLEAK)	+= structleak_plugin.so
-gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_VERBOSE)	+= -fplugin-arg-structleak_plugin-verbose
-gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL)	+= -fplugin-arg-structleak_plugin-byref-all
-gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK)	+= -DSTRUCTLEAK_PLUGIN
+gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_VERBOSE)	\
+		+= -fplugin-arg-structleak_plugin-verbose
+gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL)	\
+		+= -fplugin-arg-structleak_plugin-byref-all
+gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK)		\
+		+= -DSTRUCTLEAK_PLUGIN
 
 gcc-plugin-$(CONFIG_GCC_PLUGIN_RANDSTRUCT)	+= randomize_layout_plugin.so
-gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_RANDSTRUCT)	+= -DRANDSTRUCT_PLUGIN
-gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_RANDSTRUCT_PERFORMANCE)	+= -fplugin-arg-randomize_layout_plugin-performance-mode
+gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_RANDSTRUCT)		\
+		+= -DRANDSTRUCT_PLUGIN
+gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_RANDSTRUCT_PERFORMANCE)	\
+		+= -fplugin-arg-randomize_layout_plugin-performance-mode
 
+# 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))
-
-export GCC_PLUGINS_CFLAGS GCC_PLUGIN GCC_PLUGIN_SUBDIR
-export DISABLE_LATENT_ENTROPY_PLUGIN
-
-# sancov_plugin.so can be only in CFLAGS_KCOV because avoid duplication.
+# The sancov_plugin.so is included via CFLAGS_KCOV, so it is removed here.
 GCC_PLUGINS_CFLAGS := $(filter-out %/sancov_plugin.so, $(GCC_PLUGINS_CFLAGS))
+export GCC_PLUGINS_CFLAGS
 
+# Add the flags to the build!
 KBUILD_CFLAGS += $(GCC_PLUGINS_CFLAGS)
+
+# All enabled GCC plugins are collected here for building below.
 GCC_PLUGIN := $(gcc-plugin-y)
-GCC_PLUGIN_SUBDIR := $(gcc-plugin-subdir-y)
+export GCC_PLUGIN
 
 # Actually do the build, if requested.
 PHONY += gcc-plugins
diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig
new file mode 100644
index 000000000000..7430a7c77a4a
--- /dev/null
+++ b/scripts/gcc-plugins/Kconfig
@@ -0,0 +1,142 @@
+preferred-plugin-hostcc := $(if-success,[ $(gcc-version) -ge 40800 ],$(HOSTCXX),$(HOSTCC))
+
+config PLUGIN_HOSTCC
+	string
+	default "$(shell,$(srctree)/scripts/gcc-plugin.sh "$(preferred-plugin-hostcc)" "$(HOSTCXX)" "$(CC)")"
+	help
+	  Host compiler used to build GCC plugins.  This can be $(HOSTCXX),
+	  $(HOSTCC), or a null string if GCC plugin is unsupported.
+
+config HAVE_GCC_PLUGINS
+	bool
+	help
+	  An arch should select this symbol if it supports building with
+	  GCC plugins.
+
+menuconfig GCC_PLUGINS
+	bool "GCC plugins"
+	depends on HAVE_GCC_PLUGINS
+	depends on PLUGIN_HOSTCC != ""
+	help
+	  GCC plugins are loadable modules that provide extra features to the
+	  compiler. They are useful for runtime instrumentation and static analysis.
+
+	  See Documentation/gcc-plugins.txt for details.
+
+if GCC_PLUGINS
+
+config GCC_PLUGIN_CYC_COMPLEXITY
+	bool "Compute the cyclomatic complexity of a function" if EXPERT
+	depends on !COMPILE_TEST	# too noisy
+	help
+	  The complexity M of a function's control flow graph is defined as:
+	   M = E - N + 2P
+	  where
+
+	  E = the number of edges
+	  N = the number of nodes
+	  P = the number of connected components (exit nodes).
+
+	  Enabling this plugin reports the complexity to stderr during the
+	  build. It mainly serves as a simple example of how to create a
+	  gcc plugin for the kernel.
+
+config GCC_PLUGIN_SANCOV
+	bool
+	help
+	  This plugin inserts a __sanitizer_cov_trace_pc() call at the start of
+	  basic blocks. It supports all gcc versions with plugin support (from
+	  gcc-4.5 on). It is based on the commit "Add fuzzing coverage support"
+	  by Dmitry Vyukov <dvyukov@google.com>.
+
+config GCC_PLUGIN_LATENT_ENTROPY
+	bool "Generate some entropy during boot and runtime"
+	help
+	  By saying Y here the kernel will instrument some kernel code to
+	  extract some entropy from both original and artificially created
+	  program state.  This will help especially embedded systems where
+	  there is little 'natural' source of entropy normally.  The cost
+	  is some slowdown of the boot process (about 0.5%) and fork and
+	  irq processing.
+
+	  Note that entropy extracted this way is not cryptographically
+	  secure!
+
+	  This plugin was ported from grsecurity/PaX. More information at:
+	   * https://grsecurity.net/
+	   * https://pax.grsecurity.net/
+
+config GCC_PLUGIN_STRUCTLEAK
+	bool "Force initialization of variables containing userspace addresses"
+	# Currently STRUCTLEAK inserts initialization out of live scope of
+	# variables from KASAN point of view. This leads to KASAN false
+	# positive reports. Prohibit this combination for now.
+	depends on !KASAN_EXTRA
+	help
+	  This plugin zero-initializes any structures containing a
+	  __user attribute. This can prevent some classes of information
+	  exposures.
+
+	  This plugin was ported from grsecurity/PaX. More information at:
+	   * https://grsecurity.net/
+	   * https://pax.grsecurity.net/
+
+config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
+	bool "Force initialize all struct type variables passed by reference"
+	depends on GCC_PLUGIN_STRUCTLEAK
+	depends on !COMPILE_TEST
+	help
+	  Zero initialize any struct type local variable that may be passed by
+	  reference without having been initialized.
+
+config GCC_PLUGIN_STRUCTLEAK_VERBOSE
+	bool "Report forcefully initialized variables"
+	depends on GCC_PLUGIN_STRUCTLEAK
+	depends on !COMPILE_TEST	# too noisy
+	help
+	  This option will cause a warning to be printed each time the
+	  structleak plugin finds a variable it thinks needs to be
+	  initialized. Since not all existing initializers are detected
+	  by the plugin, this can produce false positive warnings.
+
+config GCC_PLUGIN_RANDSTRUCT
+	bool "Randomize layout of sensitive kernel structures"
+	select MODVERSIONS if MODULES
+	help
+	  If you say Y here, the layouts of structures that are entirely
+	  function pointers (and have not been manually annotated with
+	  __no_randomize_layout), or structures that have been explicitly
+	  marked with __randomize_layout, will be randomized at compile-time.
+	  This can introduce the requirement of an additional information
+	  exposure vulnerability for exploits targeting these structure
+	  types.
+
+	  Enabling this feature will introduce some performance impact,
+	  slightly increase memory usage, and prevent the use of forensic
+	  tools like Volatility against the system (unless the kernel
+	  source tree isn't cleaned after kernel installation).
+
+	  The seed used for compilation is located at
+	  scripts/gcc-plgins/randomize_layout_seed.h.  It remains after
+	  a make clean to allow for external modules to be compiled with
+	  the existing seed and will be removed by a make mrproper or
+	  make distclean.
+
+	  Note that the implementation requires gcc 4.7 or newer.
+
+	  This plugin was ported from grsecurity/PaX. More information at:
+	   * https://grsecurity.net/
+	   * https://pax.grsecurity.net/
+
+config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
+	bool "Use cacheline-aware structure randomization"
+	depends on GCC_PLUGIN_RANDSTRUCT
+	depends on !COMPILE_TEST	# do not reduce test coverage
+	help
+	  If you say Y here, the RANDSTRUCT randomization will make a
+	  best effort at restricting randomization to cacheline-sized
+	  groups of elements.  It will further not randomize bitfields
+	  in structures.  This reduces the performance hit of RANDSTRUCT
+	  at the cost of weakened randomization.
+
+endif
diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile
index 326254653bd0..aa0d0ec6936d 100644
--- a/scripts/gcc-plugins/Makefile
+++ b/scripts/gcc-plugins/Makefile
@@ -14,8 +14,6 @@ else
   export HOST_EXTRACXXFLAGS
 endif
 
-export HOSTLIBS
-
 $(obj)/randomize_layout_plugin.o: $(objtree)/$(obj)/randomize_layout_seed.h
 quiet_cmd_create_randomize_layout_seed = GENSEED $@
 cmd_create_randomize_layout_seed = \
@@ -29,7 +27,4 @@ always := $($(HOSTLIBS)-y)
 
 $(foreach p,$($(HOSTLIBS)-y:%.so=%),$(eval $(p)-objs := $(p).o))
 
-subdir-y := $(GCC_PLUGIN_SUBDIR)
-subdir-  += $(GCC_PLUGIN_SUBDIR)
-
 clean-files += *.so
diff --git a/scripts/gcc-plugins/gcc-common.h b/scripts/gcc-plugins/gcc-common.h
index f46750053377..552d5efd7cb7 100644
--- a/scripts/gcc-plugins/gcc-common.h
+++ b/scripts/gcc-plugins/gcc-common.h
@@ -392,13 +392,6 @@ static inline struct cgraph_node *cgraph_alias_target(struct cgraph_node *n)
 }
 #endif
 
-#if BUILDING_GCC_VERSION >= 4007 && BUILDING_GCC_VERSION <= 4009
-#define cgraph_create_edge(caller, callee, call_stmt, count, freq, nest) \
-	cgraph_create_edge((caller), (callee), (call_stmt), (count), (freq))
-#define cgraph_create_edge_including_clones(caller, callee, old_call_stmt, call_stmt, count, freq, nest, reason) \
-	cgraph_create_edge_including_clones((caller), (callee), (old_call_stmt), (call_stmt), (count), (freq), (reason))
-#endif
-
 #if BUILDING_GCC_VERSION <= 4008
 #define ENTRY_BLOCK_PTR_FOR_FN(FN)	ENTRY_BLOCK_PTR_FOR_FUNCTION(FN)
 #define EXIT_BLOCK_PTR_FOR_FN(FN)	EXIT_BLOCK_PTR_FOR_FUNCTION(FN)
@@ -723,10 +716,23 @@ static inline const char *get_decl_section_name(const_tree decl)
 #define varpool_get_node(decl) varpool_node::get(decl)
 #define dump_varpool_node(file, node) (node)->dump(file)
 
-#define cgraph_create_edge(caller, callee, call_stmt, count, freq, nest) \
+#if BUILDING_GCC_VERSION >= 8000
+#define cgraph_create_edge(caller, callee, call_stmt, count, freq) \
+	(caller)->create_edge((callee), (call_stmt), (count))
+
+#define cgraph_create_edge_including_clones(caller, callee,	\
+		old_call_stmt, call_stmt, count, freq, reason)	\
+	(caller)->create_edge_including_clones((callee),	\
+		(old_call_stmt), (call_stmt), (count), (reason))
+#else
+#define cgraph_create_edge(caller, callee, call_stmt, count, freq) \
 	(caller)->create_edge((callee), (call_stmt), (count), (freq))
-#define cgraph_create_edge_including_clones(caller, callee, old_call_stmt, call_stmt, count, freq, nest, reason) \
-	(caller)->create_edge_including_clones((callee), (old_call_stmt), (call_stmt), (count), (freq), (reason))
+
+#define cgraph_create_edge_including_clones(caller, callee,	\
+		old_call_stmt, call_stmt, count, freq, reason)	\
+	(caller)->create_edge_including_clones((callee),	\
+		(old_call_stmt), (call_stmt), (count), (freq), (reason))
+#endif
 
 typedef struct cgraph_node *cgraph_node_ptr;
 typedef struct cgraph_edge *cgraph_edge_p;