Date: Sat, 16 Feb 2008 14:31:47 -0800 From: Marcel Moolenaar <xcllnt@mac.com> To: Rafal Jaworowski <raj@semihalf.com> Cc: Marcel Moolenaar <marcel@freebsd.org>, Perforce Change Reviews <perforce@freebsd.org> Subject: Re: PERFORCE change 135517 for review Message-ID: <504560A3-EABB-4896-8B3E-C7FC89F31EFB@mac.com> In-Reply-To: <47B75EB3.2020001@semihalf.com> References: <200802162141.m1GLfgkj048217@repoman.freebsd.org> <47B75EB3.2020001@semihalf.com>
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On Feb 16, 2008, at 2:07 PM, Rafal Jaworowski wrote: > Marcel Moolenaar wrote: >> http://perforce.freebsd.org/chv.cgi?CH=135517 >> >> Change 135517 by marcel@marcel_jnpr on 2008/02/16 21:41:02 >> >> Save U-Boot's registers at startup and restore them when >> performing a syscall. This way we don't have to compile >> code specially to avoid using those registers. Otherwise >> we have to encode knowledge of those registers in at least >> 4 makefiles and introduce a build knob to enable it all. >> This does not allow us to build everything with a single >> build world. >> > > Hi Marcel, > > I'm not quite sure this is sufficient... I already had a similar > save/restore > in place, but there is some general problem with U-Boot that leads > to hangs > (experienced): Interesting, I didn't see any such problems with 1.3.2-rc1. > - U-Boot does not handle interrupts so there's no context save/ > restore of > exceptions, other than very few cases > > - there's one paricular asynchronous way for U-Boot code to regain > control > without those dedicated r14/29 regs saved: decrementer, which can > hit anytime > while in the app code, and which usually leads to hangs/corruption > as U-Boot > code use them blindly It's really best if U-Boot deals with that. > PS. I guess it would be good to synchronise somehow the work, as we > seem to > tackle the same pieces, which is a waste of resources. Yes, definitely... -- Marcel Moolenaar xcllnt@mac.com
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