From: Zhang Hong-W17904 (H.Zhang@motorola.com)
Date: Tue Jan 30 2001 - 20:46:36 EST
> -----Original Message----- > From: Arlet Ottens [mailto:arlet@ladybug.xs4all.nl] > Sent: Tuesday, January 30, 2001 7:36 PM > To: uclinux-dev@uClinux.org > Subject: Re: [uClinux-dev] Is supervisor/user mode is necessary for > uCLinux ? > > > Mahadev K Cholachagudda wrote: > > > I have some experience with m68k-coldfire 5206e code. The > ColdFire do have > > superuser/user mode. > > > > But the Linux should provide the protections for the kernel. If say > > application programmer writes an application which directly > update the > > status of say interrupts, then the whole mechanism of > protection is lost. > > This is going to be a problem, since uClinux doesn't use an > MMU (even on > ports that have user/supervisor mode), and there's no memory > protection. > Even if the user mode process can't change the interrupt > status directly, it > could still overwrite kernel data structures, and crash your system. > > Depending on your platform, it may be feasible to implement some form > of memory protection in the uClinux kernel. For instance, if your CPU > has support for user and supervisor memory spaces, you could protect > the kernel from userspace interference. Although you may not > be able to > protect userspace applications from each other. > > Note that the kernel currently doesn't offer support for this kind > of memory protection, so you need to add it yourself. > So, what about the uClinux 2.4.X on these issues? > -- > Arlet Ottens / Talent Store / Seattle Torn / Art Teen Lost > Very funny, Scotty ... now beam down my clothes. > This message resent by the uclinux-dev@uclinux.org list > server http://www.uClinux.org/ > This message resent by the uclinux-dev@uclinux.org list server http://www.uClinux.org/
This archive was generated by hypermail 2.1.4 : Thu Sep 19 2002 - 13:19:28 EDT