How can I mark some RAM unusable by Linux at runtime? I know that it could be done before booting but not runtime.
Bye, Antonio. On Thursday 20 April 2006 23:03, Antonio Di Bacco wrote: > Yes, I also thought this too. Anything important should stay already in RAM > but there is a chance that something bad could happen. Probably the best > thing is what you suggested as second option but I have not so much ram. My > CGI writes the downloaded new software in RAM and then I should directly > jump to u-boot without leaving Linux the chance to mix things up and then > u-boot should copy the RAM to the flash. It seems a strange procedure but > what else could be done with 4MB flash and 16 MB ram? > > Bye, > Antonio. > > On Thursday 20 April 2006 22:18, White wrote: > > make it easy: if you start an application which do the flash and after > > this a reset.. nothing should happen. I do it that way. > > the application resist completly in RAM .. and all important libs are > > in RAm or in Filesystem Cache. > > It's only important that you pretend any Application from accessing > > Datafiles or start of new application ... > > > > Alternativly, you can put it in a reserved RAM Area ( mark it not > > usable by Linux) and put a Flash Code in your Bootloader (U-boot?) > > after a reset.... > > > > But overwrite a cramfs works for me on >100 times without problems. > > > > Am Thu, 20 Apr 2006 21:54:45 +0200 schrieb Antonio Di Bacco > > > > <antonio.dibacco at aruba.it> : > > > Yes you are right, it is not a good idea to overwrite working cramfs > > > filesystem. But what happens if I download the new cramfs plus kernel > > > in RAM, do a checksum and then, completely in kernel mode, disabling > > > all the interrupts, I write to flash? No process could complain that I > > > am overwriting because no one is executing. > > > > > > Bye, > > > Antonio. > > > > > > On Wednesday 19 April 2006 09:42, Wojciech Kromer wrote: > > > > Dnia 2006-04-06 22:38, U?ytkownik Antonio Di Bacco napisa?: > > > > > Hi, > > > > > > > > > > how could I upgrade my cramfs rootfs? I have a CGI in the rootfs > > > > > that receives the new rootfs from a web interface and then tries to > > > > > write it in the flash. While overwriting the old cramfs, the CGI > > > > > will continue to work? something weird could happen? > > > > > > > > Generally it's not a good idea to override working filesystem ( I've > > > > tried to do it once). > > > > > > > > You can have two separate copies of filesystem, one to work with, and > > > > another to overwrite, it requires more flash. > > > > Another way is working in initrd, it requires more RAM. > > > > You can also use jffs2 or jffs3 (experimental) to have read-write > > > > filesystem, and change applications only, not whole filesystem (be > > > > carefull with changing busybox or libraries!) > > > > > > _______________________________________________ > > > Linuxppc-embedded mailing list > > > Linuxppc-embedded at ozlabs.org > > > https://ozlabs.org/mailman/listinfo/linuxppc-embedded > > > > _______________________________________________ > > Linuxppc-embedded mailing list > > Linuxppc-embedded at ozlabs.org > > https://ozlabs.org/mailman/listinfo/linuxppc-embedded > > _______________________________________________ > Linuxppc-embedded mailing list > Linuxppc-embedded at ozlabs.org > https://ozlabs.org/mailman/listinfo/linuxppc-embedded
