> Space as well as time. Space is more important factor. Got it. Presumably you're saving to on-chip SRAM, not DRAM, even for non-secure state.
Generic code should care about both space & time too, but in cases where there's a trade-off between the two there's very clearly a need for SoC specific code (or generic code configurability of some description). > > > Hence the Save layout is not linear on OMAP4 and restore is handled in by > > > Secure CODE > > > which is fixed for a SOC > > > > Fair enough, but this is an OMAP4 implementation choice, not a general > > statement about SoCs. (Correct me if I'm wrong.) > > > Yes. But other SOCs can implement such model as well. Absolutely. (.. and sorry my mail was imprecise: the comment above referred to non-linear layout, not the fact that there's fixed secure code.) -Bobby > -----Original Message----- > From: Shilimkar, Santosh [mailto:santosh.shilim...@ti.com] > Sent: 18 October 2010 08:09 > To: Bobby Batacharia; Jon Callan; linaro-dev@lists.linaro.org > Subject: RE: Common ARM context save/restore code > > > -----Original Message----- > > From: Bobby Batacharia [mailto:bobby.batacha...@arm.com] > > Sent: Monday, October 18, 2010 12:33 PM > > To: Shilimkar, Santosh; Jon Callan; linaro-dev@lists.linaro.org > > Subject: RE: Common ARM context save/restore code > > > > Hi, > > > > Thanks for the response. > > > > > The pre-defined locations are needed because not every registers > > > needs > > to > > > be saved. For example in GIC, pending. Clear, Set sets of > register > > > are pretty much same with inverted logic and can be > easily decoded > > > without saving all of them but just one type of it. Hence > the Save > > > layout > > > > Interesting. Why the optimization though - is the intent to > save time > > or context space? Every cycle may count, but our > investigations lead > > us to believe that the time for any shutdown is dominated by cache > > (L1) clean times. > > > Space as well as time. Space is more important factor. > > > > Hence the Save layout > > > is not linear on OMAP4 and restore is handled in by Secure CODE > > > which is fixed for a SOC > > > > Fair enough, but this is an OMAP4 implementation choice, > not a general > > statement about SoCs. (Correct me if I'm wrong.) > > > Yes. But other SOCs can implement such model as well. > > > > Yes... Again I am not saying that you can't have generic > code doing > > > that.It's doable but it will end up with some SOC specific > > execeptions. > > > > Understood. > > > -- IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
