如何开发Linux内核？

如何开发Linux内核？ 

下面是在Ubuntu下的输出：

root@myhostname # make
make: Warning: File `Makefile' has modification time 11 s in the future
make -C /lib/modules/3.13.0-24-generic/build M=/root modules
make[1]: Entering directory `/usr/src/linux-headers-3.13.0-24-generic'
make[2]: Warning: File `/root/Makefile' has modification time 10 s in the future
CC [M] /root/hello-1.o
make[2]: warning: Clock skew detected. Your build may be incomplete.
Building modules, stage 2.
make[2]: Warning: File `/root/Makefile' has modification time 8.9 s in the future
MODPOST 1 modules
CC /root/hello-1.mod.o
LD [M] /root/hello-1.ko
make[2]: warning: Clock skew detected. Your build may be incomplete.
make[1]: Leaving directory `/usr/src/linux-headers-3.13.0-24-generic'
make: warning: Clock skew detected. Your build may be incomplete.

~
root@myhostname # ls
A B.c hello-1.ko hello-1.o modules.order MyFirstJavaProgram.java
A.c dns hello-1.mod.c IP.txt Module.symvers SumOfN-thPowersIsAnN-thPower
B hello-1.c hello-1.mod.o Makefile MyFirstJavaProgram.class SumOfN-thPowersIsAnN-thPower.c

~
root@myhostname # insmod ./hello-1.ko

~
root@myhostname # cat /var/log/kern.log
Feb 2 00:48:18 cmt-ub14x64-02 kernel: [8216591.312610] hello_1: module license 'unspecified' taints kernel.
Feb 2 00:48:18 cmt-ub14x64-02 kernel: [8216591.312617] Disabling lock debugging due to kernel taint
Feb 2 00:48:18 cmt-ub14x64-02 kernel: [8216591.312641] hello_1: module verification failed: signature and/or required key missing - tainting kernel
Feb 2 00:48:18 cmt-ub14x64-02 kernel: [8216591.313139] Hello world 1.

~
root@myhostname # cat /proc/modules
hello_1 12426 0 - Live 0xffffffffa01e9000 (POF)
nls_iso8859_1 12713 0 - Live 0xffffffffa01e4000
joydev 17381 0 - Live 0xffffffffa0183000
hid_generic 12548 0 - Live 0xffffffffa01db000
udf 89723 0 - Live 0xffffffffa01c4000
crc_itu_t 12707 1 udf, Live 0xffffffffa01bf000
psmouse 102222 0 - Live 0xffffffffa01a5000
serio_raw 13462 0 - Live 0xffffffffa017e000
hid_hyperv 13059 0 - Live 0xffffffffa012e000
hyperv_keyboard 12777 0 - Live 0xffffffffa00c6000
hid 106148 2 hid_generic,hid_hyperv, Live 0xffffffffa018a000
nfsd 280297 2 - Live 0xffffffffa0135000
auth_rpcgss 59338 1 nfsd, Live 0xffffffffa011e000
nfs_acl 12837 1 nfsd, Live 0xffffffffa00c1000
nfs 236636 0 - Live 0xffffffffa00e3000
hyperv_fb 17593 1 - Live 0xffffffffa00bb000
i2c_piix4 22155 0 - Live 0xffffffffa00b0000
lockd 93977 2 nfsd,nfs, Live 0xffffffffa00cb000
mac_hid 13205 0 - Live 0xffffffffa004f000
sunrpc 284404 6 nfsd,auth_rpcgss,nfs_acl,nfs,lockd, Live 0xffffffffa0069000
fscache 63988 1 nfs, Live 0xffffffffa0058000
lp 17759 0 - Live 0xffffffffa0028000
parport 42348 1 lp, Live 0xffffffffa0043000
hv_utils 19003 0 - Live 0xffffffffa003d000
hv_storvsc 17785 2 - Live 0xffffffffa0010000
hv_vmbus 50383 5 hid_hyperv,hyperv_keyboard,hyperv_fb,hv_utils,hv_storvsc, Live 0xffffffffa002f000
floppy 69370 0 - Live 0xffffffffa0016000
tulip 59672 0 - Live 0xffffffffa0000000

~
root@myhostname # rmmod hello-1

~
root@myhostname # cat /proc/modules
nls_iso8859_1 12713 0 - Live 0xffffffffa01e4000
joydev 17381 0 - Live 0xffffffffa0183000
hid_generic 12548 0 - Live 0xffffffffa01db000
udf 89723 0 - Live 0xffffffffa01c4000
crc_itu_t 12707 1 udf, Live 0xffffffffa01bf000
psmouse 102222 0 - Live 0xffffffffa01a5000
serio_raw 13462 0 - Live 0xffffffffa017e000
hid_hyperv 13059 0 - Live 0xffffffffa012e000
hyperv_keyboard 12777 0 - Live 0xffffffffa00c6000
hid 106148 2 hid_generic,hid_hyperv, Live 0xffffffffa018a000
nfsd 280297 2 - Live 0xffffffffa0135000
auth_rpcgss 59338 1 nfsd, Live 0xffffffffa011e000
nfs_acl 12837 1 nfsd, Live 0xffffffffa00c1000
nfs 236636 0 - Live 0xffffffffa00e3000
hyperv_fb 17593 1 - Live 0xffffffffa00bb000
i2c_piix4 22155 0 - Live 0xffffffffa00b0000
lockd 93977 2 nfsd,nfs, Live 0xffffffffa00cb000
mac_hid 13205 0 - Live 0xffffffffa004f000
sunrpc 284404 6 nfsd,auth_rpcgss,nfs_acl,nfs,lockd, Live 0xffffffffa0069000
fscache 63988 1 nfs, Live 0xffffffffa0058000
lp 17759 0 - Live 0xffffffffa0028000
parport 42348 1 lp, Live 0xffffffffa0043000
hv_utils 19003 0 - Live 0xffffffffa003d000
hv_storvsc 17785 2 - Live 0xffffffffa0010000
hv_vmbus 50383 5 hid_hyperv,hyperv_keyboard,hyperv_fb,hv_utils,hv_storvsc, Live 0xffffffffa002f000
floppy 69370 0 - Live 0xffffffffa0016000
tulip 59672 0 - Live 0xffffffffa0000000

~
root@myhostname # cat /var/log/kern.log
Feb 2 00:48:18 cmt-ub14x64-02 kernel: [8216591.312610] hello_1: module license 'unspecified' taints kernel.
Feb 2 00:48:18 cmt-ub14x64-02 kernel: [8216591.312617] Disabling lock debugging due to kernel taint
Feb 2 00:48:18 cmt-ub14x64-02 kernel: [8216591.312641] hello_1: module verification failed: signature and/or required key missing - tainting kernel
Feb 2 00:48:18 cmt-ub14x64-02 kernel: [8216591.313139] Hello world 1.
Feb 2 00:53:10 cmt-ub14x64-02 kernel: [8216883.303516] Goodbye world 1.