On 10/22/2014 21:02, Ben Hutchings wrote: > On Thu, 2014-10-23 at 01:22 +0200, Ralf Baechle wrote: >> On Wed, Oct 22, 2014 at 11:15:40PM +0100, Ben Hutchings wrote: >> >>>> >>>> That's probably more of an implementation detail. I'm more concerned about >>>> the overall bloat. I think many embedded users are so addivted to benchmark >>>> results that this going to make or break the whole scheme. >>> >>> If you can make relocation a configuration option (as on x86), it would >>> allow distributions to build multiplatform kernels without preventing >>> embedded users from building a kernel optimised for their specific >>> system. But I know very little about MIPS or how intrusive the changes >>> for relocation would have to be. Perhaps it would be too much of a >>> maintenance burden to make this an option. >> >> The scope of the changes is relativly limited - we're much more concerned >> about the impact on binary size, memory size or performance of the >> various approaches under discussion. >> >> I wonder kernels for which platforms would Debian want to unify? > > I don't have high expectations for being able to unify those we > currently support. Realistically, I expect that most development effort > will go into new platforms. (What we saw with ARM was that > multi-platform was implemented for most ARMv7 platforms (for which we > now need only 2 configurations) but only slowly for older chips (4 > configurations, and that's after dropping 2 platforms).) > > Anyway, we have one 32-bit configuration for each byte order > (4kc-malta), and the following 64-bit configurations: > > [big-endian] > r4k-ip22: CONFIG_SGI_IP22, CONFIG_CPU_R4X00 > r5k-ip32: CONFIG_SGI_IP32, CONFIG_CPU_R5000 As far as I know, IRIX includes kernels specific to each SGI system (IPxx), but it seems they're CPU agnostic. They are relocatable, though. Been awhile since I watched sash boot followed by an IRIX kernel, but it does 3-4 relocations before finally booting. So a relocatable MIPS kernel on the SGI platforms seems possible. Probably requires arcane knowledge of ARCS, though. Bootloader-wise, Stan's 'arcload' can handle booting multiple kernels across various SGI platforms. We used it on the Gentoo SGI LiveCD back in 2006 to create a single CD that could boot on IP22, IP27, IP30, & IP32, using different kernels for each system and CPU (I think there was one volume header slot left at the end for arcload itself). -- Joshua Kinard Gentoo/MIPS kumba@xxxxxxxxxx 4096R/D25D95E3 2011-03-28 "The past tempts us, the present confuses us, the future frightens us. And our lives slip away, moment by moment, lost in that vast, terrible in-between." --Emperor Turhan, Centauri Republic
