Re: Is the FreeBSD ABI compatibility policy documented anywhere
On 2009.09.24 15:26:34 -0500, Stef Walter wrote: It seems that FreeBSD has an ABI compatibility policy where major versions remain ABI and API compatible throughout minor point versions. That is to say that the kernel interfaces and libraries for (eg) 7-STABLE, 7.1-RELEASE, 7.2-RELEASE are not supposed to change. It's not entirely that simple. The ABI on a stable branch like 7.x should be backward compatible, but there isn't a guarantee of forward compatibility. IE, 7.0 binary should be able to run on 7.x, but a 7.2 binary might not run on 7.0. It should be more or less the same with the API's. PS. do note that there is no 100% guarantee. At times the defacto policy might be violated if there are very good reasons for doing so. This would e.g. an important fix for something where the changed ABI, more likely K(kernel)BI, change should affect few people and the change is required for fixing some important bug. Is this a policy of the project? If so, is it documented anywhere? Or is it just a convention? I don't remember seeing it ever documented, just discussed. What I wrote above is also just my understanding of curreny defact policy. -- Simon L. Nielsen ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: Is the FreeBSD ABI compatibility policy documented anywhere
Simon L. Nielsen si...@freebsd.org writes: It's not entirely that simple. The ABI on a stable branch like 7.x should be backward compatible, but there isn't a guarantee of forward compatibility. IE, 7.0 binary should be able to run on 7.x, but a 7.2 binary might not run on 7.0. It should be more or less the same with the API's. PS. do note that there is no 100% guarantee. Correct, but we're getting closer to that now that we have symbol versioning - although we won't reach 100% until we have versioned symbols in *all* libraries, which is currently not the case. Even then, a developer might break the ABI by mistake, but hopefully we'd catch that before it made it into a release. DES -- Dag-Erling Smørgrav - d...@des.no ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: Is the FreeBSD ABI compatibility policy documented anywhere
,--- You/Dag-Erling (Sat, 10 Oct 2009 19:11:50 +0200) * | Simon L. Nielsen si...@freebsd.org writes: | It's not entirely that simple. The ABI on a stable branch like 7.x | should be backward compatible, but there isn't a guarantee of forward | compatibility. IE, 7.0 binary should be able to run on 7.x, but a 7.2 | binary might not run on 7.0. It should be more or less the same with | the API's. | | Correct, but we're getting closer to that now that we have symbol | versioning - although we won't reach 100% until we have versioned | symbols in *all* libraries, which is currently not the case. Even then, | a developer might break the ABI by mistake, but hopefully we'd catch | that before it made it into a release. It's important to note that symbol compatibility is not the whole thing -- the behaviour on exceptions may be equally important to some applications. E.g. CMUCL code has to handle different ways to notify of memory protection failures this way: #if __FreeBSD_version 74 #define PROTECTION_VIOLATION_SIGNAL SIGBUS #define PROTECTION_VIOLATION_CODE BUS_PAGE_FAULT #else #define PROTECTION_VIOLATION_SIGNAL SIGSEGV #define PROTECTION_VIOLATION_CODE SEGV_ACCERR #endif A CMUCL binary built on a pre-7.1 (?) release of FreeBSD, will crash almost immediately when run on 7.1 (well, if memory serves). -- Alex -- alex-goncha...@comcast.net -- ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: Is the FreeBSD ABI compatibility policy documented anywhere
On Sat, Oct 10, 2009 at 02:11:07PM -0400, Alex Goncharov wrote: ,--- You/Dag-Erling (Sat, 10 Oct 2009 19:11:50 +0200) * | Simon L. Nielsen si...@freebsd.org writes: | It's not entirely that simple. The ABI on a stable branch like 7.x | should be backward compatible, but there isn't a guarantee of forward | compatibility. IE, 7.0 binary should be able to run on 7.x, but a 7.2 | binary might not run on 7.0. It should be more or less the same with | the API's. | | Correct, but we're getting closer to that now that we have symbol | versioning - although we won't reach 100% until we have versioned | symbols in *all* libraries, which is currently not the case. Even then, | a developer might break the ABI by mistake, but hopefully we'd catch | that before it made it into a release. It's important to note that symbol compatibility is not the whole thing -- the behaviour on exceptions may be equally important to some applications. E.g. CMUCL code has to handle different ways to notify of memory protection failures this way: #if __FreeBSD_version 74 #define PROTECTION_VIOLATION_SIGNAL SIGBUS #define PROTECTION_VIOLATION_CODE BUS_PAGE_FAULT #else #define PROTECTION_VIOLATION_SIGNAL SIGSEGV #define PROTECTION_VIOLATION_CODE SEGV_ACCERR #endif A CMUCL binary built on a pre-7.1 (?) release of FreeBSD, will crash almost immediately when run on 7.1 (well, if memory serves). This has been an issue for 7.0, and it was explicitely handled, see r174254. pgpFdLByvBSc7.pgp Description: PGP signature
Re: Is the FreeBSD ABI compatibility policy documented anywhere
,--- You/Kostik (Sat, 10 Oct 2009 21:20:48 +0300) * | A CMUCL binary built on a pre-7.1 (?) release of FreeBSD, will crash | almost immediately when run on 7.1 (well, if memory serves). | | This has been an issue for 7.0, and it was explicitely handled, see r174254. I know it was (I was the one who first ran into the problem, way back then). My point here was to state that the behavior on signals is almost as important as symbols' compatibility. As for it was, see this few-days-old thread: http://groups.google.com/group/comp.lang.lisp/browse_thread/thread/287d1a57226f0cda/a6805cf10ca0cab9?q=cmucllnk=nl; I found an even easier way to crash CMUCL 19c/19f on FreeBSD 7.1 where the last message was posted today. Although most messages there are totally unrelated to CMUCL, FreeBSD (in fact, almost anything relevant), somebody, somewhere still hit the issue a few days ago (I am not inclined to analyze his environment, frankly). The question, Will a FreeBSD 7.2 (e.g.) build run all right on FreeBSD 8.0 (e.g.)?, is often asked, and I think it is impossible to give any guarantees -- the best one can realistically say, is, probably (with compatibility libraries, in some case). At least, I don't give any assurances for the binaries I upload to http://common-lisp.net/project/cmucl/downloads: I build against the latest code on a few branches of FreeBSD (RELENG and CURRENT) -- and if a 7.2 build runs for you on 7.1 and/or 8.0, you are in luck (and I do expect this), but it may not, and who will tell you it will, without trying? -- Alex -- alex-goncha...@comcast.net -- ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Is the FreeBSD ABI compatibility policy documented anywhere
It seems that FreeBSD has an ABI compatibility policy where major versions remain ABI and API compatible throughout minor point versions. That is to say that the kernel interfaces and libraries for (eg) 7-STABLE, 7.1-RELEASE, 7.2-RELEASE are not supposed to change. Is this a policy of the project? If so, is it documented anywhere? Or is it just a convention? Cheers, Stef ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: Is the FreeBSD ABI compatibility policy documented anywhere
Stef Walter wrote: It seems that FreeBSD has an ABI compatibility policy where major versions remain ABI and API compatible throughout minor point versions. That is to say that the kernel interfaces and libraries for (eg) 7-STABLE, 7.1-RELEASE, 7.2-RELEASE are not supposed to change. Is this a policy of the project? If so, is it documented anywhere? Or is it just a convention? It is a policy of the project but I don't think our policies are written down as such. I think you will find it referenced in many places in a sideways manner rather than directly. Possibly in the developer handbook Cheers, Stef ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: Is the FreeBSD ABI compatibility policy documented anywhere
On Thu, 24 Sep 2009 14:00:04 -0700 Julian Elischer jul...@elischer.org wrote: Stef Walter wrote: It seems that FreeBSD has an ABI compatibility policy where major versions remain ABI and API compatible throughout minor point versions. That is to say that the kernel interfaces and libraries for (eg) 7-STABLE, 7.1-RELEASE, 7.2-RELEASE are not supposed to change. Is this a policy of the project? If so, is it documented anywhere? Or is it just a convention? It is a policy of the project but I don't think our policies are written down as such. I think you will find it referenced in many places in a sideways manner rather than directly. Possibly in the developer handbook The only place I found it directly referenced was in http://wiki.freebsd.org/VendorInformation -- Bruce Cran ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
