linux-nv-oot/scripts/conftest/Makefile

###########################################################################
# SPDX-License-Identifier: MIT
# SPDX-FileCopyrightText: Copyright (c) 2023 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
#
# Makefile file for NVIDIA Linux conftest
###########################################################################

#
# The parent makefile is expected to define:
#
#  NV_KERNEL_SOURCES : The root of the kernel source tree.
#  NV_KERNEL_OUTPUT  : The kernel's output tree.
#  NV_KERNEL_MODULES : A whitespace-separated list of modules to build.
#  ARCH              : The target CPU architecture: x86_64|arm64|powerpc
#
# Kbuild provides the variables:
#
# $(src) : The directory containing this Kbuild file.
# $(obj) : The directory where the output from this build is written.
#

#
# The conftest.sh script tests various aspects of the target kernel.
# The per-module Kbuild files included above should:
#
# - Append to the NV_CONFTEST_*_COMPILE_TESTS variables to indicate
#   which conftests they require.
# - Append to the NV_OBJECTS_DEPEND_ON_CONFTEST variable any object files
#   that depend on conftest.
#
# The conftest machinery below will run the requested tests and
# generate the appropriate header files.
#

CC ?= cc
LD ?= ld

NV_CONFTEST_SCRIPT := $(src)/conftest.sh
NV_CONFTEST_HEADER := $(obj)/conftest/headers.h

NV_CONFTEST_CMD := /bin/sh $(NV_CONFTEST_SCRIPT) \
  "$(CC)" $(ARCH) $(NV_KERNEL_SOURCES) $(NV_KERNEL_OUTPUT)

NV_CFLAGS_FROM_CONFTEST := $(shell $(NV_CONFTEST_CMD) build_cflags)

NV_CONFTEST_CFLAGS = $(NV_CFLAGS_FROM_CONFTEST) $(EXTRA_CFLAGS) -fno-pie

NV_CONFTEST_COMPILE_TEST_HEADERS := $(obj)/conftest/macros.h
NV_CONFTEST_COMPILE_TEST_HEADERS += $(obj)/conftest/functions.h
NV_CONFTEST_COMPILE_TEST_HEADERS += $(obj)/conftest/symbols.h
NV_CONFTEST_COMPILE_TEST_HEADERS += $(obj)/conftest/types.h
NV_CONFTEST_COMPILE_TEST_HEADERS += $(obj)/conftest/generic.h

NV_CONFTEST_HEADERS := $(obj)/conftest/patches.h
NV_CONFTEST_HEADERS += $(obj)/conftest/headers.h
NV_CONFTEST_HEADERS += $(NV_CONFTEST_COMPILE_TEST_HEADERS)

all: $(NV_CONFTEST_HEADERS)

#
# Generate a header file for a single conftest compile test. Each compile test
# header depends on conftest.sh, as well as the generated conftest/headers.h
# file, which is included in the compile test preamble.
#

$(obj)/conftest/compile-tests/%.h: $(NV_CONFTEST_SCRIPT) $(NV_CONFTEST_HEADER)
	@mkdir -p $(obj)/conftest/compile-tests
	@echo "  CONFTEST: $(notdir $*)"
	@$(NV_CONFTEST_CMD) compile_tests '$(NV_CONFTEST_CFLAGS)' \
	  $(notdir $*) > $@

#
# Concatenate a conftest/*.h header from its constituent compile test headers
#
# $(1): The name of the concatenated header
# $(2): The list of compile tests that make up the header
#

define NV_GENERATE_COMPILE_TEST_HEADER
  $(obj)/conftest/$(1).h: $(addprefix $(obj)/conftest/compile-tests/,$(addsuffix .h,$(2)))
	@mkdir -p $(obj)/conftest
	@# concatenate /dev/null to prevent cat from hanging when $$^ is empty
	@cat $$^ /dev/null > $$@
endef

#
# Generate the conftest compile test headers from the lists of compile tests
# provided by the module-specific Kbuild files.
#

NV_CONFTEST_FUNCTION_COMPILE_TESTS += devm_thermal_of_zone_register
NV_CONFTEST_FUNCTION_COMPILE_TESTS += iio_dev_opaque_has_mlock
NV_CONFTEST_GENERIC_COMPILE_TESTS ?=
NV_CONFTEST_MACRO_COMPILE_TESTS ?=
NV_CONFTEST_SYMBOL_COMPILE_TESTS ?=
NV_CONFTEST_TYPE_COMPILE_TESTS ?=

$(eval $(call NV_GENERATE_COMPILE_TEST_HEADER,functions,$(NV_CONFTEST_FUNCTION_COMPILE_TESTS)))
$(eval $(call NV_GENERATE_COMPILE_TEST_HEADER,generic,$(NV_CONFTEST_GENERIC_COMPILE_TESTS)))
$(eval $(call NV_GENERATE_COMPILE_TEST_HEADER,macros,$(NV_CONFTEST_MACRO_COMPILE_TESTS)))
$(eval $(call NV_GENERATE_COMPILE_TEST_HEADER,symbols,$(NV_CONFTEST_SYMBOL_COMPILE_TESTS)))
$(eval $(call NV_GENERATE_COMPILE_TEST_HEADER,types,$(NV_CONFTEST_TYPE_COMPILE_TESTS)))

$(obj)/conftest/patches.h: $(NV_CONFTEST_SCRIPT)
	@mkdir -p $(obj)/conftest
	@$(NV_CONFTEST_CMD) patch_check > $@


# Each of these headers is checked for presence with a test #include; a
# corresponding #define will be generated in conftest/headers.h.
NV_HEADER_PRESENCE_TESTS = \
  generated/autoconf.h \
  linux/kconfig.h \
  linux/iosys-map.h

# Filename to store the define for the header in $(1); this is only consumed by
# the rule below that concatenates all of these together.
NV_HEADER_PRESENCE_PART = $(addprefix $(obj)/conftest/header_presence/,$(addsuffix .part,$(1)))

# Define a rule to check the header $(1).
define NV_HEADER_PRESENCE_CHECK
  $$(call NV_HEADER_PRESENCE_PART,$(1)): $$(NV_CONFTEST_SCRIPT) $(obj)/conftest/uts_release
	@mkdir -p $$(dir $$@)
	@$$(NV_CONFTEST_CMD) test_kernel_header '$$(NV_CONFTEST_CFLAGS)' '$(1)' > $$@
endef

# Evaluate the rule above for each header in the list.
$(foreach header,$(NV_HEADER_PRESENCE_TESTS),$(eval $(call NV_HEADER_PRESENCE_CHECK,$(header))))

# Concatenate all of the parts into headers.h.
$(obj)/conftest/headers.h: $(call NV_HEADER_PRESENCE_PART,$(NV_HEADER_PRESENCE_TESTS))
	@cat $^ > $@

clean-dirs := $(obj)/conftest

# For any object files that depend on conftest, declare the dependency here.
$(addprefix $(obj)/,$(NV_OBJECTS_DEPEND_ON_CONFTEST)): | $(NV_CONFTEST_HEADERS)

# Sanity checks of the build environment and target system/kernel

BUILD_SANITY_CHECKS = \
  cc_sanity_check \
  cc_version_check \
  module_symvers_sanity_check

.PHONY: $(BUILD_SANITY_CHECKS)

$(BUILD_SANITY_CHECKS):
	@$(NV_CONFTEST_CMD) $@ full_output

# Perform all sanity checks before generating the conftest headers

$(NV_CONFTEST_HEADERS): | $(BUILD_SANITY_CHECKS)

# Make the conftest headers depend on the kernel version string

$(obj)/conftest/uts_release: NV_GENERATE_UTS_RELEASE
	@mkdir -p $(dir $@)
	@NV_UTS_RELEASE="// Kernel version: `$(NV_CONFTEST_CMD) compile_tests '$(NV_CONFTEST_CFLAGS)' uts_release`"; \
	if ! [ -f "$@" ] || [ "$$NV_UTS_RELEASE" != "`cat $@`" ]; \
	then echo "$$NV_UTS_RELEASE" > $@; fi

.PHONY: NV_GENERATE_UTS_RELEASE

$(NV_CONFTEST_HEADERS): $(obj)/conftest/uts_release