无法在Android JellyBean上构建hello world内核模块

Question

我正在尝试在Android JellyBean上构建一个简单的内核模块.

码:

#include <linux/module.h>  /* Needed by all modules */
#include <linux/kernel.h>  /* Needed for KERN_ALERT */

MODULE_LICENSE("GPL");
MODULE_AUTHOR("test");
MODULE_DESCRIPTION("Android ko test");

int init_module(void)
{
   printk(KERN_ALERT, "Hello world\n");

   // A non 0 return means init_module failed; module can't be loaded.
   return 0;
}

void cleanup_module(void)
{
  printk(KERN_ALERT "Goodbye world 1.\n");
}

Makefile文件:

obj-m +=hello.o

KERNELDIR ?= ~/android/kernel
PWD := $(shell pwd)
CROSS_COMPILE=~/android/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/arm-eabi-
ARCH=arm

default:
    $(MAKE) -C $(KERNELDIR) M=$(PWD) ARCH=arm CROSS_COMPILE=$(CROSS_COMPILE) modules

clean:
    $(MAKE) -C $(KERNELDIR) M=$(PWD) clean

输出:

make -C ~/android/kernel M=/home/test/testmod ARCH=arm CROSS_COMPILE=~/android/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin/arm-eabi- modules
make[1]: Entering directory `/home/test/android/kernel'

  ERROR: Kernel configuration is invalid.
         include/generated/autoconf.h or include/config/auto.conf are missing.
         Run 'make oldconfig && make prepare' on kernel src to fix it.


  WARNING: Symbol version dump /home/test/android/kernel/Module.symvers
           is missing; modules will have no dependencies and modversions.

  CC [M]  /home/test/testmod/hello.o
In file included from <command-line>:0:
/home/test/android/kernel/include/linux/kconfig.h:4:32: error: generated/autoconf.h: No such file or directory
In file included from /home/test/android/kernel/arch/arm/include/asm/types.h:4,
                 from include/linux/types.h:4,
                 from include/linux/list.h:4,
                 from include/linux/module.h:9,
                 from /home/test/testmod/hello.c:1:
include/asm-generic/int-ll64.h:11:29: error: asm/bitsperlong.h: No such file or directory
In file included from /home/test/android/kernel/arch/arm/include/asm/posix_types.h:38,
                 from include/linux/posix_types.h:47,
                 from include/linux/types.h:17,
                 from include/linux/list.h:4,
                 from include/linux/module.h:9,
                 from /home/test/testmod/hello.c:1:
include/asm-generic/posix_types.h:70:5: warning: "__BITS_PER_LONG" is not defined
error, forbidden warning: posix_types.h:70
make[2]: *** [/home/test/testmod/hello.o] Error 1
make[1]: *** [_module_/home/test/testmod] Error 2
make[1]: Leaving directory `/home/test/android/kernel'
make: *** [default] Error 2

如果我按照输出中的建议,并在内核上运行'make oldconfig && make prepare',它会引导我通过几十个内核配置是/否问题.之后,编译在下一个错误时仍然失败,这个错误大约是bitsperlong.h.

Answer 1

Android将输出二进制文件放在out目录下.因此,例如,人们可以有out/target/product/<target name>/obj/KERNEL_OBJ/或$ANDROID_PRODUCT_OUT/obj/KERNEL_OBJ/是否$ANDROID_PRODUCT_OUT被定义.此目录可能具有与不同供应商不同的名称,但只是包含该目录的目录vmlinux.

因此,当您在Android repo下编译内核模块时,您应该make在模块目录中提交如下所示的命令.

make -C $ANDROID_PRODUCT_OUT/obj/KERNEL_OBJ/ M=`pwd` ARCH=arm CROSS_COMPILE=arm-eabi- modules