Compiling kernelsD1204475780Astella#The source for the Plan 9 kernels (other than the original#standalone file server kernels in /sys/src/fs) is kept in#/sys/src/9. The distribution includes kernels for the Intel PC, the#Alpha PC, a MIPS-based workstation called a Carrera, the Compaq iPAQ#(bitsy), and a PowerPC-based embedded system.##The machine-independent source code is in /sys/src/9/port. Each#architecture also has a machine-dependent directory: pc, alphapc,#carrera, mpc, and so on.##To build a kernel for a pre-existing configuration you cd into the#corresponding arch directory and then run mk with the CONF variable#set to the configuration file you want to use.##For example to build the default terminal kernel pcf:#! cd /sys/src/9/pc#! mk 'CONF=pcf'##To install the new kernel copy the generated kernel with the name of#the config file preceded by 9(eg., 9pcf) to your 9fat directory:#! 9fat:#! cp /sys/src/9/pc/9pcf /n/9fat/##It is recommended that you keep your old kernel around so you can#boot it in case something is wrong with the new one, for details of#how to do this see plan9.ini(8)##HOW TO CONFIGURE A CUSTOM KERNEL##A distinction is made between the kernel configuration for terminals#and for CPU servers: they have slightly different boot sequences,#and different kernel-to-user memory ratios.##Each kernel is described by a configuration file. For example, this#is an abridged version of the pcdisk terminal configuration file#/sys/src/9/pc/pcdisk.##! dev#! 	root#! 	cons#! 	arch#! 	env#! 	ip#! #! link#! 	ether2000 ether8390#! 	ethermedium#! #! misc#! 	archmp mp apic#! 	kfs.root#! 	vgamach64xx +cur#! 	vgamga2164w +cur#! #! ip#! 	il#! 	tcp#! #! port#! 	int cpuserver = 0;#! #! boot boot #S/sdC0/#! 	il#! 	local##The format is simple: each word on each indented line is the name of#an object file to link. The non-indented lines mark sections. You#can include or exclude various drivers by inserting or removing#lines.##The [bootdir] section describes how the the #//boot directory is#populated.##You might want to edit a pre-existing kernel configuration file if#for example you want to build a standalone terminal/CPU/auth server#but the default server configuration doesn't have your video card#driver. To rebuild 9pccpuf with your card driver, edit#/sys/src/9/pc/pccpuf and add the appropriate vga line.##For multiprocessors, make sure the line##! 	archmp		mp apic##appears in your config file or the new kernel will only use one CPU.##Then rebuild that kernel and install it:##! cd /sys/src/9/pc#! mk 'CONF=pccpuf'#! cp 9pccpuf /386#! 9fat:#! cp 9pccpuf /n/9fat/##The argument to mk specifies which configuration file to use. The#default for the pc kernels is ``pc''.##It is usually best to play in a copy of the config files rather than#edit them directly. Then you can mk with##! mk 'CONF=pcmyusername'##But even if you overwrite the existing files, remember that you can#always refer to the originals stored in /n/dump (see yesterday(1).)##COMPILING WITHOUT WRITE PERMISSIONS FOR /SYS##Personally, I prefer not to pollute my default install files. I#create a set of empty directories that mirror /sys/src with srcbind:##! 	#!/bin/rc##! 	if(! test -d $1)#! 		exit 'base directory not found (test -d ' ^$1 ^' failed)'##! 	for (d in (sys sys/src sys/src/9) )#! 		if(! test -d $1/$d ) #! 			mkdir $1/$d##! 	for(d in (boot port pc))#! 		if(! test -d $1/sys/src/9/$d ) #! 			mkdir $1/sys/src/9/$d##! 	bind -b -c $1/sys/src/9/boot /sys/src/9/boot#! 	bind -b -c $1/sys/src/9/port /sys/src/9/port#! 	bind -b -c $1/sys/src/9/pc /sys/src/9/pc##and then##! 	ramfs#! 	srcbind /tmp#! 	cp /sys/src/9/pc/pcf /tmp/sys/src/9/pc/pcf##edit pcf##! 	cd /sys/src/9/pc#! 	mk 'CONF=pcf'##! 	ls -l /tmp/sys/src/9/pc/9pcf##--rwxrwxr-x M 111 maht maht 2446793 Mar 5 22:56#/tmp/sys/src/9/pc/9pcf##It would be wise not to use ramfs if you want to keep your updated#copy of pcf##Copy to 9fat and /386 in the normal way. You only need it in /386 if#you boot diskless terminals as they get their kernels from /386##In this way you can compile and use a new kernel without having to#be in sys or have write permissions turned off.#