On Friday, 1 April 2011, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Friday 01 April 2011 23:10:04 Kevin Hilman wrote: >> Arnd Bergmann <arnd@xxxxxxxx> writes: >> >> > On Friday 01 April 2011, Detlef Vollmann wrote: >> >> On 04/01/11 15:54, Arnd Bergmann wrote: >> > >> >> > 9. All interesting work is going into a handful of platforms, all of which >> >> > Â Â are ARMv7 based. >> >> Define interesting. >> > >> > The ones that are causing the churn that we're talking about. >> > Platforms that have been working forever and only need to get >> > the occasional bug fix are boring, i.e. not the problem. >> >> I'm not sure I follow the ARMv7-only thinking either. >> >> Picking ARMv7 only would be a good way to avoid part of the problem, but >> IMO, it doesn't really address the root causes. ÂPart of the ugliness of >> the platform-specific hackery (and the "churn" to clean some of it up) >> is precisely due to support for multiple ARM architecture versions, and >> the various SoCs in a family that use them. ÂFor example, linux-omap >> supports OMAP1 (ARMv5), OMAP2 (ARMv6), OMAP3 (ARMv7) and OMAP4 (ARMv7 >> SMP), and OMAP2/3/4 in a single binary. >> >> Also, since we've only very recently got to the point of being able to >> support ARMv6 + ARMv7 UP & SMP in the same kernel, making a decision now >> that only ARMv7 is important seems like a step backwards. ÂIf the >> ultimate goal is getting to a point where we have infrastrucure that can >> be cross-SoC, surely this same infrastrucure should support multiple ARM >> architecture revisions. > > Yes, forget about the ARMv7 part of my proposal, that was not a main point. > > If we decide to have a new clean platform variant the way I suggested, > it would be nice to support all machines in a single kernel binary, > and at least v6+v7 is a solved problem. > > Supporting a second kernel binary up to v5 with the same source is also > simple, as would be big-endian/little-endian variants, or thumb2/arm variants. > We might not want to do all combinations from the start though, and I would > choose ARMv6/v7-thumb2-le simply because that's what Linaro is focusing > on. The idea is to start with a clearly defined set, but write the code > in a way that makes it possible to extend in other directions. Thumb-2 is ARMv7 only. If you want a v6+v7 binary it would need to be compiled to ARM. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
