撰写并运行内核模块
mkdir -p src/modules/hello_imx6ull
cd src/modules/hello_imx6ull
vi hello_imx6ull.c
hello_imx6ull.c
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
static int __init hello_imx6ull_init(void)
{
pr_info("hello imx6ull module init\n");
return 0;
}
static void __exit hello_imx6ull_exit(void)
{
pr_info("hello imx6ull module exit\n");
}
module_init(hello_imx6ull_init);
module_exit(hello_imx6ull_exit);
MODULE_DESCRIPTION("hello imx6ull - Linux Lab real board module example");
MODULE_AUTHOR("iOSDevLog <iosdevlog@iosdevlog.com>");
MODULE_LICENSE("GPL");
Makefile
# ARCH = arm
# CROSS_COMPILE = arm-linux-gnueabi-
KERNEL_SRC ?= /lib/modules/`uname -r`/build
obj-m += hello_imx6ull.o
modules:
$(MAKE) -C $(KERNEL_SRC) M=$$PWD modules;
modules-install:
$(MAKE) -C $(KERNEL_SRC) M=$$PWD modules-install;
clean:
$(MAKE) -C $(KERNEL_SRC) M=$$PWD clean;
$(RM) *.ko;
编译该内核模块
make modules m=hello_imx6ull
make modules-install m=hello_imx6ull
make modules-upload
在真板上启动内核模块
make login
登录 IMX6ULL。
sudo modprobe hello_imx6ull
modprobe: ERROR: could not insert 'hello_imx6ull': Exec format error
原因未知。
2021/01/04 重头执行
将 预览版 从 TF卡 fire-config刷机 到 emmc。
重新执行了一遍 next 分支的操作。
已经有了 hello_imx6ull 模块，这次新建一个 hello_linux_lab_hello。
cp -r src/modules/hello src/modules/hello_linux_lab_hello
cd src/modules/hello_linux_lab_hello
mv hello.c hello_linux_lab_hello.c
hello_linux_lab_hello.c
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
static int __init hello_linux_lab_imx6ull_init(void)
{
pr_info("hello linux-lab imx6ull module init\n");
return 0;
}
static void __exit hello_linux_lab_imx6ull_exit(void)
{
pr_info("hello linux-lab imx6ull module exit\n");
}
module_init(hello_linux_lab_imx6ull_init);
module_exit(hello_linux_lab_imx6ull_exit);
MODULE_DESCRIPTION("hello linux-lab imx6ull - Linux Lab real board module example");
MODULE_AUTHOR("iOSDevLog <iosdevlog@iosdevlog.com>");
MODULE_LICENSE("GPL");
Makeifle
KERNEL_SRC ?= /lib/modules/`uname -r`/build
obj-m += hello_linux_lab_imx6ull.o
modules:
$(MAKE) -C $(KERNEL_SRC) M=$$PWD modules;
modules-install:
$(MAKE) -C $(KERNEL_SRC) M=$$PWD modules-install;
clean:
$(MAKE) -C $(KERNEL_SRC) M=$$PWD clean;
rm -f *.ko;
Compile a kernel module and upload it
make modules m=hello_linux_lab_imx6ull
make modules-install m=hello_linux_lab_imx6ull
make modules-upload
验证
make login
查看 hello_linux_lab_imx6ull.ko 类型。
debian@npi:~$ ls /lib/modules/4.19.35+/extra/
hello.ko hello_imx6ull.ko hello_linux_lab_imx6ull.ko
sudo apt install file
file /lib/modules/4.19.35+/extra/*
同 hello.ko 一样。
/lib/modules/4.19.35+/extra/hello.ko: ELF 32-bit LSB relocatable, ARM, EABI5 version 1 (SYSV), BuildID[sha1]=c669968dec7cfd12ff354756b21f4cb6653fc74b, with debug_info, not stripped
/lib/modules/4.19.35+/extra/hello_imx6ull.ko: ELF 32-bit LSB relocatable, ARM, EABI5 version 1 (SYSV), BuildID[sha1]=70f2771a81593d78ef1aea082b7bbf1ab54d6e11, with debug_info, not stripped
/lib/modules/4.19.35+/extra/hello_linux_lab_imx6ull.ko: ELF 32-bit LSB relocatable, ARM, EABI5 version 1 (SYSV), BuildID[sha1]=a72a2e20aa70392320fdcef88bb7844ae38a7c2c, with debug_info, not stripped
查看 hello_linux_lab_imx6ull 信息。
debian@npi:~$ sudo modprobe hello_linux_lab_imx6ull
[ 1177.900660] hello linux-lab imx6ull module init
debian@npi:~$ lsmod | grep hello_linux_lab_imx6ull
hello_linux_lab_imx6ull 16384 0
debian@npi:~$ dmesg | grep "hello linux"
[ 1177.900660] hello linux-lab imx6ull module init
debian@npi:~$ modinfo hello_linux_lab_imx6ull
filename: /lib/modules/4.19.35+/extra/hello_linux_lab_imx6ull.ko
license: GPL
author: iOSDevLog <iosdevlog@iosdevlog.com>
description: hello linux-lab imx6ull - Linux Lab real board module example
srcversion: 23F6F2563D3621635B131C2
depends:
name: hello_linux_lab_imx6ull
vermagic: 4.19.35+ SMP preempt mod_unload modversions ARMv7 p2v8
总结
年前不知什么原因，导致 Exec format error 错误，今天用干净的环境重新执行一下又可以了。
确实要使用相同的环境（抽象出虚拟层）。