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diff --git a/util/ADLO/README b/util/ADLO/README new file mode 100644 index 0000000000..8fa8d4fb13 --- /dev/null +++ b/util/ADLO/README @@ -0,0 +1,231 @@ +========================================== +$Id: README,v 1.1 2002/11/25 02:07:53 rminnich Exp $ +========================================== + +ADLO + + A project to combine LinuxBIOS and BOCHS BIOS to add support + for booting legacy applications, such as Microsoft Windows. + +========================================== + +Boot Overvew: + + ADLO requires an boot loader with ELF support. + In our case it is either LinuxBIOS or EtherBOOT. + + Sample execution paths: + +LinuxBIOS -> ADLO -> LILO -> LINUX + +LinuxBIOS -> EtherBOOT -> ADLO -> LILO -> LINUX + + Then it can start any real mode application. + In our case it could be LILO or GRUB, but + choices are not limited to this. + +========================================== + +ADLO overview: + + -Elf header + -mainteance routines + -bochs bios + -vga bios + +------------------------------------------ + +Elf header + + hand crafted binary. Currently there are 3 diff binaries + for three different sizes of payload (65kb,113kb,129kb). + + they are catted at beginning of file + +------------------------------------------ + +mainteance routines + + this is the loader.s file which gets compiled into loader.o binary + + it is catted 2nd right after elf header and it is where + control is being transfered when the elf is executed. + + it consist of : + -tuneups: + select device to boot + set memory for Int15/EAX=E820 + enable LBA + copy LinuxBIOS table [TODO] + -shadow : + enable/write/read + -copy: + bochs @ 0xF00000 + video bios (binary only) @ 0xC00000 + -switch + from Real to Protected Mode + -jump + jmp to the bios at 0xFFFF:0x0000 + + we must have bios payload always at 1kb + offset from start of ELF payload so loader.o + must be always 1024 bytes. + +------------------------------------------ + +BOCHS BIOS + + we have taken the boch's project and just extracted + its bios from it only. it took us (so far) only + minor modifications in order to make it work. + + basically it is the following directory in the + bochs sources + + bochs-cvs/bochs/bios + + of all files there the rombios.c is the key file. + Most of the times our patches are against current + version of the rombios.c file. We try to feed back + the patches to bochs maintainers so that's possible + to use the bochs bios as is. + + the boch's related stuff are in bochs subdirectory. + + building boch's bios is as simple as + + cd bochs/bochs-cvs/bochs/bios + make + + the resulting file rombios.bin is our bios image. + + ----- + At present time, it is recommended to use + dev86-0.16.3 + my patch in order to compile + bochs' bios. The dev86 package can be found + at: + + http://www.cix.co.uk/~mayday/ + + prepatched sources at: + + http://www.missl.cs.umd.edu/~adam/dev86-0.16.3-MSR.tgz + +------------------------------------------ + +Video BIOS + + Video BIOS we use is binary only, so far. + + At the present time we are using the original + Video BIOS as supplied from the system. + + To get the image simply type: + + make makevideobios + + The right thing will happen. For refernece the + magic line in the Makefile is: + + videobios: + dd if=/proc/kcore \ + of=./video.bios.bin \ + bs=1 count=65536 skip=790528 + + --------------- + + We assume it is located at 0xC00000-0xE00000 + and we use 'dd and /proc/kcore to extract it + (obviously it works as root only). + + Obviously it needs to be done with original + (as shipped by manufactuer bios) so it should + be done as the first step of the ADLO setup. + + --------------- + + The /proc/kcore is in ELF format (linux kernel + 2.4.x and later) so if we want to get accurate + image of ram we must skip the ELF header. + The magic command is : + + readelf -a /proc/kcore + +Program Headers: + Type Offset VirtAddr PhysAddr FileSiz MemSiz + NOTE 0x0007d4 0x00000000 0x00000000 0x005b0 0x00000 + LOAD 0x001000 0xc0000000 0x00000000 0xff60000 0xff60000 + ^^^^^^^^ + + There we look for the first LOAD section, and see what + is its offset (for us it is 0x1000) + + --------------- + + 64KiB = 65536 + + 0x0C 00 00 + 0x10 00 = 790528 + + --------------- + + On technical note in our case video bios + is just 48kb, but for paranoia sake we copy + 64kb. + +========================================== + +Environment overview + +ADLO is an ELF file and thus can be loaded either directly from 1) +LinuxBIOS, or 2) via EtherBOOT, or 3) via EtherBOOT+ AA patch for FS +support. + +1) +Both LinuxBIOS and ADLO are on the same EEPROM chip. From end-user +viewpoint it is probably the most similar to the bios classic. +(computer boots up and just loads whatever is in MBR). + +2) +Set it up in /tftpboot directory on dhcp/tftp server and have it served +from there. (this is how we did the development) + +3) +Use AA patch and put it as /kernel file and it will be then loaded by +etherboot from local hard disk. + + +------------------------------------------ + +Before ADLO starts. + + ADLO requires an boot loader with ELF support. + In our case it is: + + -LinuxBIOS + -LinuxBIOS and EtherBOOT + -LinuxBIOS and EtherBOOT + AA polled I/O patch (w/ FS support). + + As little as LinuxBIOS only is required to get ADLO + up and running. + + For development purposes it is recommended full set of + LinuxBIOS + EtherBOOT and boot via DHCP/TFTP. + +------------------------------------------ + +After ADLO finish. + + ADLO will attempt to locate the first hard disk + and read MBR from it and execute. + + Then it can start any real mode application. + In our case it could be LILO or GRUB + but choices are not limited to this. + + In our case it would cause LILO to load + (fully usable) and from there it was able to + execute simple programs. so far the list + of the program is limited to linux which + runs somewhat. More to come in future. + +========================================== |