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openwrt/include/kernel.mk
Mark Mentovai 802bfe0806 kernel: disable stack validation for external module builds as needed 
c3e31b6a9b and 5f8e587240 disable stack validation when the build
host is not running Linux, as the objtool kernel build tool required for
stack validation is not portable to other build host environments. This
was achieved by setting CONFIG_STACK_VALIDATION= in KERNEL_MAKEOPTS, and
by setting SKIP_STACK_VALIDATION=1 in the environment. KERNEL_MAKEOPTS
only has effect for the kernel build, not for external module builds,
but through kernel 5.14, SKIP_STACK_VALIDATION worked to disable this
feature too, so stack validation was disabled for external module builds
as well. Since kernel 0d989ac2c90b, the kernel build no longer considers
SKIP_STACK_VALIDATION, so the feature will be disabled for the kernel
build, but not for external module builds.

When building OpenWrt on a non-Linux build host targeting x86 (the only
target architecture for which OpenWrt enables the kernel
CONFIG_STACK_VALIDATION) and using kernel 5.15 (such as via
CONFIG_TESTING_KERNEL), this caused a build failure during any external
module build, such as kmod-button-hotplug. This manifested as build
errors such as:

  make[4]: *** No rule to make target
  '.../build_dir/target-x86_64_musl/linux-x86_64/button-hotplug/button-hotplug.o',
  needed by
  '.../build_dir/target-x86_64_musl/linux-x86_64/button-hotplug/button-hotplug.mod'.
  Stop.

Although button-hotplug.c was present, the implicit rule to make
$(obj)/%.o from $(src)/%.c in the kernel's scripts/Makefile.build could
not be satisfied in this case, as it also depends on $(objtool_dep),
non-empty as a result of the failure to propagate disabling of stack
validation to external module builds, in a configuration where it is not
possible to build objtool.

KERNEL_MAKEOPTS is used for just the kernel build itself, while
KERNEL_MAKE_FLAGS is used for both the kernel build and for external
module builds. This restores the ability to build OpenWrt in such
configurations by moving the CONFIG_STACK_VALIDATION= make argument from
KERNEL_MAKEOPTS to KERNEL_MAKE_FLAGS where it is able to affect external
module builds properly.

Note that the kernel's objtool and related configuration have seen a
major overhaul since kernel 5.15, and may need more attention again
after 22922deae13f, in kernel 5.19.

Signed-off-by: Mark Mentovai <mark@mentovai.com>
2022-10-20 09:53:23 +02:00

302 lines
9.5 KiB
Makefile
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# SPDX-License-Identifier: GPL-2.0-only
#
# Copyright (C) 2006-2020 OpenWrt.org
ifneq ($(filter check,$(MAKECMDGOALS)),)
CHECK:=1
DUMP:=1
endif
ifneq ($(SOURCE_DATE_EPOCH),)
ifndef DUMP
KBUILD_BUILD_TIMESTAMP:=$(shell perl -e 'print scalar gmtime($(SOURCE_DATE_EPOCH))')
endif
endif
ifeq ($(__target_inc),)
ifndef CHECK
include $(INCLUDE_DIR)/target.mk
endif
endif
ifeq ($(DUMP),1)
KERNEL?=<KERNEL>
BOARD?=<BOARD>
LINUX_VERSION?=<LINUX_VERSION>
LINUX_VERMAGIC?=<LINUX_VERMAGIC>
else
ifeq ($(CONFIG_EXTERNAL_TOOLCHAIN),)
export GCC_HONOUR_COPTS=s
endif
LINUX_KMOD_SUFFIX=ko
ifneq (,$(findstring uml,$(BOARD)))
KERNEL_CC?=$(HOSTCC)
KERNEL_CROSS?=
else
KERNEL_CC?=$(TARGET_CC)
KERNEL_CROSS?=$(TARGET_CROSS)
endif
ifeq ($(TARGET_BUILD),1)
PATCH_DIR ?= $(CURDIR)/patches$(if $(wildcard ./patches-$(KERNEL_PATCHVER)),-$(KERNEL_PATCHVER))
FILES_DIR ?= $(foreach dir,$(wildcard $(CURDIR)/files $(CURDIR)/files-$(KERNEL_PATCHVER)),"$(dir)")
endif
KERNEL_BUILD_DIR ?= $(BUILD_DIR)/linux-$(BOARD)$(if $(SUBTARGET),_$(SUBTARGET))
LINUX_DIR ?= $(KERNEL_BUILD_DIR)/linux-$(LINUX_VERSION)
LINUX_UAPI_DIR=uapi/
LINUX_VERMAGIC:=$(strip $(shell cat $(LINUX_DIR)/.vermagic 2>/dev/null))
LINUX_VERMAGIC:=$(if $(LINUX_VERMAGIC),$(LINUX_VERMAGIC),unknown)
LINUX_UNAME_VERSION:=$(KERNEL_BASE)
ifneq ($(findstring -rc,$(LINUX_VERSION)),)
LINUX_UNAME_VERSION:=$(LINUX_UNAME_VERSION)-$(strip $(lastword $(subst -, ,$(LINUX_VERSION))))
endif
LINUX_KERNEL:=$(KERNEL_BUILD_DIR)/vmlinux
ifneq (,$(findstring -rc,$(LINUX_VERSION)))
LINUX_SOURCE:=linux-$(LINUX_VERSION).tar.gz
else
LINUX_SOURCE:=linux-$(LINUX_VERSION).tar.xz
endif
ifneq (,$(findstring -rc,$(LINUX_VERSION)))
LINUX_SITE:=https://git.kernel.org/torvalds/t
else ifeq ($(call qstrip,$(CONFIG_EXTERNAL_KERNEL_TREE))$(call qstrip,$(CONFIG_KERNEL_GIT_CLONE_URI)),)
LINUX_SITE:=@KERNEL/linux/kernel/v$(word 1,$(subst ., ,$(KERNEL_BASE))).x
else
LINUX_UNAME_VERSION:=$(strip $(shell cat $(LINUX_DIR)/include/config/kernel.release 2>/dev/null))
endif
MODULES_SUBDIR:=lib/modules/$(LINUX_UNAME_VERSION)
TARGET_MODULES_DIR:=$(LINUX_TARGET_DIR)/$(MODULES_SUBDIR)
ifneq ($(TARGET_BUILD),1)
PKG_BUILD_DIR ?= $(KERNEL_BUILD_DIR)/$(if $(BUILD_VARIANT),$(PKG_NAME)-$(BUILD_VARIANT)/)$(PKG_NAME)$(if $(PKG_VERSION),-$(PKG_VERSION))
endif
endif
ifneq (,$(findstring uml,$(BOARD)))
LINUX_KARCH=um
else ifneq (,$(findstring $(ARCH) , aarch64 aarch64_be ))
LINUX_KARCH := arm64
else ifneq (,$(findstring $(ARCH) , arceb ))
LINUX_KARCH := arc
else ifneq (,$(findstring $(ARCH) , armeb ))
LINUX_KARCH := arm
else ifneq (,$(findstring $(ARCH) , mipsel mips64 mips64el ))
LINUX_KARCH := mips
else ifneq (,$(findstring $(ARCH) , powerpc64 ))
LINUX_KARCH := powerpc
else ifneq (,$(findstring $(ARCH) , sh2 sh3 sh4 ))
LINUX_KARCH := sh
else ifneq (,$(findstring $(ARCH) , i386 x86_64 ))
LINUX_KARCH := x86
else
LINUX_KARCH := $(ARCH)
endif
KERNEL_MAKE = $(MAKE) $(KERNEL_MAKEOPTS)
KERNEL_MAKE_FLAGS = \
KCFLAGS="$(call iremap,$(BUILD_DIR),$(notdir $(BUILD_DIR))) $(filter-out -fno-plt,$(call qstrip,$(CONFIG_EXTRA_OPTIMIZATION))) $(call qstrip,$(CONFIG_KERNEL_CFLAGS))" \
HOSTCFLAGS="$(HOST_CFLAGS) -Wall -Wmissing-prototypes -Wstrict-prototypes" \
CROSS_COMPILE="$(KERNEL_CROSS)" \
ARCH="$(LINUX_KARCH)" \
KBUILD_HAVE_NLS=no \
KBUILD_BUILD_USER="$(call qstrip,$(CONFIG_KERNEL_BUILD_USER))" \
KBUILD_BUILD_HOST="$(call qstrip,$(CONFIG_KERNEL_BUILD_DOMAIN))" \
KBUILD_BUILD_TIMESTAMP="$(KBUILD_BUILD_TIMESTAMP)" \
KBUILD_BUILD_VERSION="0" \
KBUILD_HOSTLDFLAGS="-L$(STAGING_DIR_HOST)/lib" \
CONFIG_SHELL="$(BASH)" \
$(if $(findstring c,$(OPENWRT_VERBOSE)),V=1,V='') \
$(if $(PKG_BUILD_ID),LDFLAGS_MODULE=--build-id=0x$(PKG_BUILD_ID)) \
cmd_syscalls= \
$(if $(__package_mk),KBUILD_EXTRA_SYMBOLS="$(wildcard $(PKG_SYMVERS_DIR)/*.symvers)")
KERNEL_NOSTDINC_FLAGS = \
-nostdinc $(if $(DUMP),, -isystem $(shell $(TARGET_CC) -print-file-name=include))
ifeq ($(call qstrip,$(CONFIG_EXTERNAL_KERNEL_TREE))$(call qstrip,$(CONFIG_KERNEL_GIT_CLONE_URI)),)
KERNEL_MAKE_FLAGS += \
KERNELRELEASE=$(LINUX_VERSION)
endif
ifneq ($(HOST_OS),Linux)
KERNEL_MAKE_FLAGS += CONFIG_STACK_VALIDATION=
export SKIP_STACK_VALIDATION:=1
endif
KERNEL_MAKEOPTS := -C $(LINUX_DIR) $(KERNEL_MAKE_FLAGS)
ifdef CONFIG_USE_SPARSE
KERNEL_MAKEOPTS += C=1 CHECK=$(STAGING_DIR_HOST)/bin/sparse
endif
PKG_EXTMOD_SUBDIRS ?= .
PKG_SYMVERS_DIR = $(KERNEL_BUILD_DIR)/symvers
define collect_module_symvers
for subdir in $(PKG_EXTMOD_SUBDIRS); do \
realdir=$$$$(readlink -f $(PKG_BUILD_DIR)); \
grep -F $(PKG_BUILD_DIR) $(PKG_BUILD_DIR)/$$$$subdir/Module.symvers >> $(PKG_BUILD_DIR)/Module.symvers.tmp; \
[ "$(PKG_BUILD_DIR)" = "$$$$realdir" ] || \
grep -F $$$$realdir $(PKG_BUILD_DIR)/$$$$subdir/Module.symvers >> $(PKG_BUILD_DIR)/Module.symvers.tmp; \
done; \
sort -u $(PKG_BUILD_DIR)/Module.symvers.tmp > $(PKG_BUILD_DIR)/Module.symvers; \
mkdir -p $(PKG_SYMVERS_DIR); \
mv $(PKG_BUILD_DIR)/Module.symvers $(PKG_SYMVERS_DIR)/$(PKG_NAME).symvers
endef
define KernelPackage/hooks
ifneq ($(PKG_NAME),kernel)
Hooks/Compile/Post += collect_module_symvers
endif
define KernelPackage/hooks
endef
endef
define KernelPackage/Defaults
FILES:=
AUTOLOAD:=
MODPARAMS:=
PKGFLAGS+=nonshared
endef
# 1: name
# 2: install prefix
# 3: module priority prefix
# 4: required for boot
# 5: module list
define ModuleAutoLoad
$(if $(5), \
mkdir -p $(2)/etc/modules.d; \
($(foreach mod,$(5), \
echo "$(mod)$(if $(MODPARAMS.$(mod)), $(MODPARAMS.$(mod)),$(if $(MODPARAMS), $(MODPARAMS)))"; )) > $(2)/etc/modules.d/$(3)$(1); \
$(if $(4), \
mkdir -p $(2)/etc/modules-boot.d; \
ln -sf ../modules.d/$(3)$(1) $(2)/etc/modules-boot.d/;))
endef
ifeq ($(DUMP)$(TARGET_BUILD),)
-include $(LINUX_DIR)/.config
endif
define KernelPackage/depends
$(STAMP_BUILT): $(LINUX_DIR)/.config
define KernelPackage/depends
endef
endef
define KernelPackage
NAME:=$(1)
$(eval $(call Package/Default))
$(eval $(call KernelPackage/Defaults))
$(eval $(call KernelPackage/$(1)))
$(eval $(call KernelPackage/$(1)/$(BOARD)))
$(eval $(call KernelPackage/$(1)/$(BOARD)/$(if $(SUBTARGET),$(SUBTARGET),generic)))
define Package/kmod-$(1)
TITLE:=$(TITLE)
SECTION:=kernel
CATEGORY:=Kernel modules
DESCRIPTION:=$(DESCRIPTION)
EXTRA_DEPENDS:=kernel (=$(LINUX_VERSION)-$(LINUX_RELEASE)-$(LINUX_VERMAGIC))
VERSION:=$(LINUX_VERSION)$(if $(PKG_VERSION),+$(PKG_VERSION))-$(if $(PKG_RELEASE),$(PKG_RELEASE),$(LINUX_RELEASE))
PKGFLAGS:=$(PKGFLAGS)
$(call KernelPackage/$(1))
$(call KernelPackage/$(1)/$(BOARD))
$(call KernelPackage/$(1)/$(BOARD)/$(if $(SUBTARGET),$(SUBTARGET),generic))
endef
ifdef KernelPackage/$(1)/conffiles
define Package/kmod-$(1)/conffiles
$(call KernelPackage/$(1)/conffiles)
endef
endif
ifdef KernelPackage/$(1)/description
define Package/kmod-$(1)/description
$(call KernelPackage/$(1)/description)
endef
endif
ifdef KernelPackage/$(1)/config
define Package/kmod-$(1)/config
$(call KernelPackage/$(1)/config)
endef
endif
$(call KernelPackage/depends)
$(call KernelPackage/hooks)
ifneq ($(if $(filter-out %=y %=n %=m,$(KCONFIG)),$(filter m y,$(foreach c,$(filter-out %=y %=n %=m,$(KCONFIG)),$($(c)))),.),)
define Package/kmod-$(1)/install
@for mod in $$(call version_filter,$$(FILES)); do \
if grep -q "$$$$$$$${mod##$(LINUX_DIR)/}" "$(LINUX_DIR)/modules.builtin"; then \
echo "NOTICE: module '$$$$$$$$mod' is built-in."; \
elif [ -e $$$$$$$$mod ]; then \
mkdir -p $$(1)/$(MODULES_SUBDIR) ; \
$(CP) -L $$$$$$$$mod $$(1)/$(MODULES_SUBDIR)/ ; \
else \
echo "ERROR: module '$$$$$$$$mod' is missing." >&2; \
exit 1; \
fi; \
done;
$(call ModuleAutoLoad,$(1),$$(1),$(filter-out 0-,$(word 1,$(AUTOLOAD))-),$(filter-out 0,$(word 2,$(AUTOLOAD))),$(sort $(wordlist 3,99,$(AUTOLOAD))))
$(call KernelPackage/$(1)/install,$$(1))
endef
$(if $(CONFIG_PACKAGE_kmod-$(1)),
else
compile: $(1)-disabled
$(1)-disabled:
@echo "WARNING: kmod-$(1) is not available in the kernel config - generating empty package" >&2
define Package/kmod-$(1)/install
true
endef
)
endif
$$(eval $$(call BuildPackage,kmod-$(1)))
$$(IPKG_kmod-$(1)): $$(wildcard $$(call version_filter,$$(FILES)))
endef
version_filter=$(if $(findstring @,$(1)),$(shell $(SCRIPT_DIR)/package-metadata.pl version_filter $(KERNEL_PATCHVER) $(1)),$(1))
# 1: priority (optional)
# 2: module list
# 3: boot flag
define AutoLoad
$(if $(1),$(1),0) $(if $(3),1,0) $(call version_filter,$(2))
endef
# 1: module list
# 2: boot flag
define AutoProbe
$(call AutoLoad,,$(1),$(2))
endef
version_field=$(if $(word $(1),$(2)),$(word $(1),$(2)),0)
kernel_version_merge=$$(( ($(call version_field,1,$(1)) << 24) + ($(call version_field,2,$(1)) << 16) + ($(call version_field,3,$(1)) << 8) + $(call version_field,4,$(1)) ))
ifdef DUMP
kernel_version_cmp=
else
kernel_version_cmp=$(shell [ $(call kernel_version_merge,$(call split_version,$(2))) $(1) $(call kernel_version_merge,$(call split_version,$(3))) ] && echo 1 )
endif
CompareKernelPatchVer=$(if $(call kernel_version_cmp,-$(2),$(1),$(3)),1,0)
kernel_patchver_gt=$(call kernel_version_cmp,-gt,$(KERNEL_PATCHVER),$(1))
kernel_patchver_ge=$(call kernel_version_cmp,-ge,$(KERNEL_PATCHVER),$(1))
kernel_patchver_eq=$(call kernel_version_cmp,-eq,$(KERNEL_PATCHVER),$(1))
kernel_patchver_le=$(call kernel_version_cmp,-le,$(KERNEL_PATCHVER),$(1))
kernel_patchver_lt=$(call kernel_version_cmp,-lt,$(KERNEL_PATCHVER),$(1))
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