编译一个linux内核模块
看源代码。
#include <linux/kernel.h> #include <linux/module.h> #if CONFIG_MODVERSIONS==1 #define MODVERSIONS #include <linux/modversions.h> #endif int init_module() { printk("Hello, I'm kernel/n"); return 0; } void cleanup_module() { printk("I'm kernel, bye/n"); }
再来看 makefile的写法
TARGET = hello
OBJS = hello.o
MDIR = drivers/misc
EXTRA_CFLAGS = -DEXPORT_SYMTAB
CURRENT = $(shell uname -r)
KDIR = /lib/modules/$(CURRENT)/build
PWD = $(shell pwd)
DEST = /lib/modules/$(CURRENT)/kernel/$(MDIR)
obj-m := $(TARGET).o
default:
make -C $(KDIR) SUBDIRS=$(PWD) modules
$(TARGET).o: $(OBJS)
$(LD) $(LD_RFLAG) -r -o $@ $(OBJS)
ifneq (,$(findstring 2.4.,$(CURRENT)))
install:
echo $(DEST) $(LD_RFLAG)
su -c "cp -v $(TARGET).o $(DEST) && /sbin/depmod -a"
else
install:
su -c "cp -v $(TARGET).ko $(DEST) && /sbin/depmod -a"
endif
clean:
-rm -f *.o *.ko .*.cmd .*.flags *.mod.c
-include $(KDIR)/Rules.make
好了 放入到位置运行makefile即可
插入模块的命令是这样的
$insmod hello.ko（PS：尽管你看不到有.ko这样的文件，但是的确是这么来做的）
用 dmesg 就可以看到 输出啦。。。。
补充一个错误：
./linux/include/asm/elf.h: In function `start_ia32_thread':
./linux/include/asm/elf.h:153: warning: implicit declaration of function `load_g
s_index'
./linux/include/asm/elf.h: In function `elf_common_init':
./linux/include/asm/elf.h:166: error: structure has no member named `r8'
./linux/include/asm/elf.h:166: error: structure has no member named `r9'
./linux/include/asm/elf.h:166: error: structure has no member named `r10'
./linux/include/asm/elf.h:166: error: structure has no member named `r11'
./linux/include/asm/elf.h:167: error: structure has no member named `r12'
./linux/include/asm/elf.h:167: error: structure has no member named `r13'
./linux/include/asm/elf.h:167: error: structure has no member named `r14'
./linux/include/asm/elf.h:167: error: structure has no member named `r15'
In file included from ./linux/include/linux/module.h:21,
from hello.c:2:
./linux/include/asm/module.h:70:2: #error unknown processor family
可能路径显示不是这样 因为我是复制出来源代码来编译的，但是错误的确是这样。其实这个错误是makefile的问题，因为用
-Wall -DMODULE -D__KERNEL__ -D__SMT__ 的编译方法在kenel2.6下不行的。所以 按照上面写的makefile 就好了。。