kbuild: Bump the build system to 5.1
Our last sync with the kernel was 5.1. Even that was a partial one
as some patches from 4.x kernels were already missing making the
transition to a modern kbuild infeasible.
We are so out of sync now, that tracking the patches and backporting
them one by one makes little sense and it's going to take ages.
This is an attempt to sync up Makefile[.lib/.kbuild].
Unfortunately due to sheer amount of patches this is not easy to review,
but that's what we decided during a community call.
One of the biggest changes is get rid of partial linking entirely and
build .a archives isntead of .o.
We diaviate from the kernel on that. Instead of calling a custom script
to create the archive symbol table, we call ar with rcTP (isntead of
rcSTP) since we want a resulting archive that's sauble with the linker.
The only affected platforms are PPC ones. Unfortunately I don't have any
of them around to test, but the objdump of the resulting files --
arch/powerpc/lib/built-in.[oa] looks identical.
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
new file mode 100644
index 0000000..5f7df50
--- /dev/null
+++ b/scripts/Makefile.gcc-plugins
@@ -0,0 +1,59 @@
+# 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-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) \
+ += -DLATENT_ENTROPY_PLUGIN
+ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
+ DISABLE_LATENT_ENTROPY_PLUGIN += -fplugin-arg-latent_entropy_plugin-disable
+endif
+export DISABLE_LATENT_ENTROPY_PLUGIN
+
+gcc-plugin-$(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-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF) \
+ += -fplugin-arg-structleak_plugin-byref
+gcc-plugin-cflags-$(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-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak_plugin.so
+gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \
+ += -DSTACKLEAK_PLUGIN
+gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \
+ += -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_STACKLEAK_TRACK_MIN_SIZE)
+ifdef CONFIG_GCC_PLUGIN_STACKLEAK
+ DISABLE_STACKLEAK_PLUGIN += -fplugin-arg-stackleak_plugin-disable
+endif
+export DISABLE_STACKLEAK_PLUGIN
+
+gcc-plugin-$(CONFIG_GCC_PLUGIN_ARM_SSP_PER_TASK) += arm_ssp_per_task_plugin.so
+ifdef CONFIG_GCC_PLUGIN_ARM_SSP_PER_TASK
+ DISABLE_ARM_SSP_PER_TASK_PLUGIN += -fplugin-arg-arm_ssp_per_task_plugin-disable
+endif
+export DISABLE_ARM_SSP_PER_TASK_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))
+# 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)
+export GCC_PLUGIN