Compile Linux Kernel Modules

ÎÒÕýÔÚѧϰдlinux device driver for embedded system.
ÎÒÓÐÒ»¸ölinuxǶÈëʽÉ豸£¬Ò²ÓÐÕâ¸öÉ豸µÄlinuxÔ´´úÂë¡£Ò²ÓÐcross compiler tool chain.
µÚÒ»²½£¬¾ÍÊÇдһ¸ö¼òµ¥µÄhelloÄ£¿é£¬È»ºó×°µ½É豸ÖС£ÒÔÑéÖ¤ÎÒÕâ¸ö¿ª·¢»·¾³¡£
ÔÚÍøÉÏËÑË÷ÁËһϣ¬ how to cross compile linux device driver
·¢ÏÖÔÚlinux´úÂë¸ùĿ¼µÄMakefileÖÐÓйØÓÚcross compileµÄÃèÊö
# Cross compiling and selecting different set of gcc/bin-utils
# ---------------------------------------------------------------------------
#
# When performing cross compilation for other architectures ARCH shall be set
# to the target architecture. (See arch/* for the possibilities).
# ARCH can be set during invocation of make:
# make ARCH=ia64
# Another way is to have ARCH set in the environment.
# The default ARCH is the host where make is executed.
# CROSS_COMPILE specify the prefix used for all executables used
# during compilation. Only gcc and related bin-utils executables
# are prefixed with $(CROSS_COMPILE).
# CROSS_COMPILE can be set on the command line
# make CROSS_COMPILE=ia64-linux-
# Alternatively CROSS_COMPILE can be set in the environment.
# Default value for CROSS_COMPILE is not to prefix executables
# Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
Ö»ÒªÖ¸¶¨ARCHºÍCROSS_COMPILE¾Í¿ÉÒÔÁË¡£
ÔÚÎÒµÄÕâ¸öMakefileÖУ¬ÒѾ­Ö¸¶¨ÁËARCH=arm£¬CROSS_COMPILE=arm-linux-
ÒòΪÔÚ±àÒëmoduleµÄʱºò£¬Ê¹ÓõÄÊÇÄں˹¹Ôìϵͳ£¬Ò²¾ÍÊÇʹÓõÄÉÏÃæËù˵µÄÕâ¸öÔÚÄÚºËÔ´Âë¸ùĿ¼µÄMakefile¡£ËùÒÔÎҾͲ»ÐèÒªÔÚÎÒµ÷ÓÃmakeµÄÃüÁîÐÐÖÐÖ¸¶¨ARCHºÍCROSS_COMPILEÁË¡£
ÓÃÀ´²âÊÔµÄhelloÄ£¿éµÄÔ´ÂëÀ´×Ô http://www.cyberciti.biz/tips/compiling-linux-kernel-module.html
hello.c
#include <linux/module.h> /* Needed by all modules */
#include <linux/kernel.h> /* Needed for KERN_INFO */
#include <linux/init.h> /* Needed for the macros */
static int __init hello_start(void)
{
printk(KERN_INFO "Loading hello module...\n");
printk(KERN_INFO "Hello world\n");
return 0;
}
static void