Dear Albrecht, In message <1414433699.5968.2@deneb.(none)> you wrote: > > Just to understand your statement correctly: do you recommend to use > ELDK 5.4 for the PowerPC instead of ELDK 5.5.x (I'm working with the > Freescale MPC5200 and the QorIQ P2020 processors)?
I have to admit that I am not in a position yet to give any recommendations based on deeper knowledge or understanding; I cannot even tell if the observed effects are known GCC bugs, or if the fact that the same effects are no longer present in 4.9.1 is because a bug was detected and fixed, or just by pure chance. > Does this apply to the kernel only, or also to user-space software, > or to u-boot? THis applies at least to U-Boot and Kernel, or more generaly to all kinds of code where you take special efforts when arranging things like the stack layout and/or the image linking. I got bitten (on a MPC5200 by the way) by the fact that GCC 4.8.x fails to provide relocation information for symbols in the (new) .data.rel.ro and .data.rel.ro.local segments. You could call this a deciciency in the U-Boot linker scripts, but then, it got "fixed" (or changed again) in gcc 4.9.1. For details, see [1] and [2]. The ARM Linux kernel folks even discuss blacklisting GCC 4.8.x for other reasons, see [3] So it's only observations of such ill effects, not real understanding of which GCC bugs are causing these, or if fixes are available, and when these were (or get) merged. I can only say that I currently use gcc 4.7.x (from ELDK 5.4) for all production builds where I need working code, resp. gcc 4.9.1 (what will become ELDK v5.7) for testing. This is just my $ 0.02. Your mileage may vary. [1] http://article.gmane.org/gmane.comp.boot-loaders.u-boot/199062 [2] http://article.gmane.org/gmane.comp.boot-loaders.u-boot/199076 [3] https://lkml.org/lkml/2014/10/10/272 Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: [email protected] Brain fried - Core dumped _______________________________________________ eldk mailing list [email protected] http://lists.denx.de/mailman/listinfo/eldk
