Question

这是一个示例Makefile，它使用关键字modules两次（除了出现在路径和PHONY中的那些）。

# Path to the kbuild Makefile of the kernel to compile against
export KERNEL_BUILD_PATH := /lib/modules/$(shell uname -r)/build
# Name of this kernel module
export KERNEL_MODULE     := hello
# List of kernel headers to include (e.g.: "linux/netdevice.h")
export KERNEL_INCLUDE    := 
# Path to the directory where kernel build artifacts should be stored
export BUILD_DIRECTORY   := build
# List of C files to compile into this kernel module
export C_FILES           := $(wildcard src/*.c)
# List of all Rust files that will be compiled into this kernel module
export RUST_FILES        := $(wildcard src/*.rs)
# Base directory of the Rust compiler
export RUST_ROOT         := /usr

# Rust compiler settings
export CARGO      = $(RUST_ROOT)/bin/xargo
export CARGOFLAGS =
export RCFLAGS    =
export RELEASE    =

-include ./config.mk


# Top-level project directory
export BASE_DIR := $(patsubst %/,%,$(dir $(abspath $(lastword $(MAKEFILE_LIST)))))


# Prevent command echoing, unless the (Kbuild-style) `V=1` parameter is set
ifneq "$(V)" "1"
.SILENT:
endif


all modules: ${BUILD_DIRECTORY}/Makefile
    @$(MAKE) -C "${KERNEL_BUILD_PATH}" M="${BASE_DIR}/${BUILD_DIRECTORY}" modules
    cp "${BUILD_DIRECTORY}/${KERNEL_MODULE}.ko" "${KERNEL_MODULE}.ko"

# Make sure there always is a target `Makefile` for kbuild in place
${BUILD_DIRECTORY}/Makefile: kbuild.mk
    @mkdir -p "${BUILD_DIRECTORY}/src"
    cp "kbuild.mk" "${BUILD_DIRECTORY}/Makefile"

insmod:
    sudo insmod "${KERNEL_MODULE}.ko"
    dmesg | tail

rmmod:
    sudo rmmod "${KERNEL_MODULE}"
    dmesg | tail

clean:
    rm -rf "${BUILD_DIRECTORY}"
    $(CARGO) clean

test: ${KERNEL_MODULE}.ko
    sudo insmod "${KERNEL_MODULE}.ko"
    sudo rmmod  "${KERNEL_MODULE}"
    dmesg | tail -3

.PHONY: all modules clean insmod rmmod test

我的问题是：

在第35行中，all modules是否指两个单独的目标，例如all和modules在一起？如果是这样，为什么我们用两个不同的名称命名相同的规则？规则不会递归吗？
在第36行中，关键字module出现在最后的重要性是什么？
第36行，M=代表什么？

Answer 1

all modules

是非常不幸的目标名称。每次Makefile被执行时都会被调用＆＃34;没有指定任何目标。当您致电make -f Makefile modules时，也会调用它。我不会那样打电话给目标。

all modules:
    @echo "Hello"

.PHONY: all modules

如果你运行这个

> make
Hello

至于 M =

value:
    @echo $(M)

M =简单地传递将在Makefile

中可见的变量

> make M=hohoho -f Makefile value
hohoho

这个Makefile中的“模块”是指什么？

1 个答案: