On Sep 26, 2007, at 9:45 PM, David Gibson wrote: > On Wed, Sep 26, 2007 at 11:19:47AM -0500, Milton Miller wrote: >> On Sep 24, 2007, at 10:46 PM, David Gibson wrote: >>> On Mon, Sep 24, 2007 at 01:54:32AM -0500, Milton Miller wrote: >>>> On Sep 23, 2007, at 10:36 PM, David Gibson wrote: >>>>> On Fri, Sep 21, 2007 at 06:05:06PM -0500, Milton Miller wrote: >>> [snip] >>>>>> +#define MIN_VERSION 2 >>>>>> +#define OUT_VERSION 16z
>>>> Actually the v1 trees has >>>> some other differences such as initrd addresses were kernel linear >>>> not >>>> real, cpus were assigned logical numbers ... so while the structure >>>> didn't change except for the header field, the contents did. >>> >>> !? what's your source for this. v2 and v3 were absolutely supposed >>> to >>> be backwards compatible with v1 which would not be the case with >>> silent semantic changes such as this. >> >> What's your souce for saying the were supposed to be backwards >> compatable? That dtc fills out the struct header so? > > Sitting next to BenH and knowing he always intended them to be so. > >> My source is my involvment when v2 was defined (they were discovered >> while writing my device tree generation code): >> >> The actual binary structure is compatable, just not the contents of >> the >> properties nor how any slave cpus wait (for some trees it doesn't >> matter). >> >> http://git.kernel.org/?p=linux/kernel/git/horms/kexec-tools- >> testing.git;a=blob;f=kexec/arch/ppc64/fs2dt.c; >> hb=b84b87747a16f0afbef6f6802bb794a94f4961d9 > > An old version of fs2dt is hardly definitive. It could just be Plain > Wrong, nothing to do with the dt version. Sorry, copy and paste error. I was tring to point out this changelog in 2.6.10: http://git.kernel.org/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git; a=commitdiff;h=e1b47549d1588ccea1fa5726eb430aae4e80f8ed > >> And some more changes just before that: >> >> http://git.kernel.org/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git; >> a=history;f=arch/ppc64/kernel/prom_init.c; >> h=e570799a84cc5328e9f0fd44592cb0b828d8c13a; >> hb=4ae24c4e8a8f68950a7774ca1cdfe69bfe4e2ffc > > I don't know what bit you're referring to in that batch of commits. The following properties changed semantics and no heuristics are employed to check for the old vs new: (1) tces changed from virtual to real (2) cpus spin on physical (hw id) not logical (0-n) Other changes in that series (3) 0->klimit is not a memreserve in the tree (we now allow overlapping reserves, but not at the time) (4) rtas properties are in a different location (but both could exist) > >> So its mostly when the kernel generated and required v1 trees, it was >> ppc64 only and had these other content and handoff semantics. If it >> were to get a v1 tree, it only copes for the boot cpu determination >> I'm not aware of any code other than the kernel that would actually >> generate a v1 tree (other than dtc, which always supporteed v2, and >> doesn't care about these differences). So trying to boot 2.6.9 (2004-10-18 cutoff) kernel from a tree for 2.6.10 would fail, and vice versa. But a 2.6.10 kernel can boot a v1 tree with properties, memreserves, and cpu ids that it expects, getting the boot-cpuid from the extra property in the tree. Is that compatible? If you only are talking about parsing the tree it is. milton _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
