On Wed, Dec 26, 2001 at 08:36:43PM +0530, Chirag Kantharia wrote: > On Wed, Dec 26, 2001 at 03:40:32PM +0100, Erik Mouw wrote: > | > Thanx for the reply. But, is there a way to invoke userland process > | > without a filesystem? > | No, but you'll need a filesystem anyway because otherwise the kernel > | can't start init. > > [Cc'ed to uclinux-dev since it's more relevant there] > > Ok; I'll confess now. My problem, is that of loading a kernel image from > a host pc into an embedded box. The flash on the embedded box's too less > to fit in the kernel, with a filesystem. How large is the flash? The smallest flash footprint I got on a StrongARM system was about 1.5MB (128k bootloader, 512k kernel, 900k rootfs), but I think I can fit it in 1MB when I make the bootloader flash partition a bit smaller and use uClibc instead of glibc. > So, I modified the init() function to load a kernel from the serial > port, and write it to the RAM, which is quite in plenty. I'm expecting > to be able to boot using the kernel image in the RAM, next. What exactly is the target architecture? > This might be incredibly stupid. I would like others to comment, > especially, if there's a better way to do things. The embedded box's > just got couple of serial ports and a couple of parallel ports. I think you'd better use the bootloader to load the kernel over the serial port. I have written a bootloader for StrongARM systems (blob, see https://sf.net/projects/blob/ ) which does exactly that. Normal use is that the bootloader loads the kernel and an optional ramdisk from flash, but you can download a kernel and a ramdisk over the serial port in case you'd like to upgrade the kernel or the flash is too small. This requires exactly 0 modifications to the kernel, and the code is quite small (the bootloader flash footprint is 16k). > I'm able to access the serial port using the serial port functions > defined in the driver for serial port. Sure, but it's all a bit of a hack; the bootloader is much better at loading kernel and ramdisk images. Erik -- J.A.K. (Erik) Mouw, Information and Communication Theory Group, Faculty of Information Technology and Systems, Delft University of Technology, PO BOX 5031, 2600 GA Delft, The Netherlands Phone: +31-15-2783635 Fax: +31-15-2781843 Email: J.A.K.Mouw@its.tudelft.nl WWW: http://www-ict.its.tudelft.nl/~erik/ -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ IRC Channel: irc.openprojects.net / #kernelnewbies Web Page: http://www.kernelnewbies.org/
