From: firstname.lastname@example.org To: email@example.com Subject: [Bug 204125] FTBFS on ppc64 big endian and gcc9 because of -mcall-aixdesc and missing __linux__ Date: Wed, 10 Jul 2019 15:37:36 +0000 Message-ID: <bug-204125-206035-bPfhYUPf4o@https.bugzilla.kernel.org/> (raw) In-Reply-To: <firstname.lastname@example.org/> https://bugzilla.kernel.org/show_bug.cgi?id=204125 Segher Boessenkool (email@example.com) changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |firstname.lastname@example.org --- Comment #1 from Segher Boessenkool (email@example.com) --- (In reply to Daniel Kolesa from comment #0) > On ppc64 big endian, the kernel builds with `-mcall-aixdesc` which since gcc > 9.x removes `__linux__` from the list of macros being defined. This is a bug. Please report at https://gcc.gnu.org/bugzilla . > This behavior > is supposed to be more correct (as it's in this case nothing but a hack, the > flag should apparently only be used when building for AIX) What makes you think that? OTOH, why does the kernel use that option? > but sadly it > breaks build since several things within the tree rely on `__linux__` being > defined and `#ifdef` some of their code based on said macro. Those are bugs as well, then. > Just removing `-mcall-aixdesc` (and using just `-mabi=elfv1`) is however not > enough, as that instead causes countless undefined references to just about > every symbol when linking `vmlinux`. It would seem that `-mcall-aixdesc` > changes the way symbols are declared in a way that is not expected. > Little endian is not affected because that one uses `-mabi=elfv2` > exclusively. Of course, that is the only defined ABI for powerpc64le after all. > Also, is there any reason not to allow an ELFv2 kernel to be built on big > endian? Building it _on_ BE works just fine, of course. But you mean building a BE kernel using the ELFv2 ABI. This is not supported; it would require writing other versions for various low-level things. ELFv2 is not supported in BE userland, either, btw. > There are some supposed performance benefits, and ELFv2 itself > supports either endianness. The current kbuild logic pretty much forces > ELFv1 for big endian and ELFv2 for little endian. ELFv2 has a few little benefits; it is newer, there were lessons learnt. It would be surprising if it has better than trivial advantages for the BE kernel though. But feel free to try, of course :-) -- You are receiving this mail because: You are watching the assignee of the bug.
next prev parent reply index Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-07-10 13:24 [Bug 204125] New: " bugzilla-daemon 2019-07-10 15:37 ` bugzilla-daemon [this message] 2019-07-10 15:41 ` [Bug 204125] " bugzilla-daemon 2019-07-10 15:57 ` bugzilla-daemon 2019-07-10 16:01 ` bugzilla-daemon 2019-07-10 16:04 ` bugzilla-daemon 2019-07-12 1:41 ` bugzilla-daemon 2019-07-12 2:11 ` bugzilla-daemon 2019-07-12 15:36 ` bugzilla-daemon 2019-09-08 14:57 ` bugzilla-daemon
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