Messages in this thread | | | Subject | Re: [PATCH 4/5] Generic BUG for powerpc | From | Michael Ellerman <> | Date | Wed, 04 Oct 2006 10:54:03 +1000 |
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On Tue, 2006-10-03 at 13:16 -0700, Jeremy Fitzhardinge wrote: > plain text document attachment (mm) > This makes powerpc use the generic BUG machinery. The biggest > difference from the previous powerpc bug code is that it no longer > reports the function name, since it is redundant with kallsyms, and > not needed in general. > > There is an overall reduction of code, since module_32/64 duplicated several > functions. > > Unfortunately there's no way to tell gcc that BUG won't return, so the > BUG macro includes a goto loop. This will generate a real jmp > instruction, which is never used.
I posted a patch a few weeks back to use __builtin_trap(), which gives GCC the hint that it's not going to return. (http://patchwork.ozlabs.org/linuxppc/patch?id=7047)
Unfortunately this generated some negative feedback from some of our crackhead ... er wonderful colleagues who want to be able to step over BUGs in some circumstances. (http://ozlabs.org/pipermail/linuxppc-dev/2006-September/026161.html)
I think they conceeded that it could be configurable, but I wasn't sure it was worth the trouble.
cheers
-- Michael Ellerman OzLabs, IBM Australia Development Lab
wwweb: http://michael.ellerman.id.au phone: +61 2 6212 1183 (tie line 70 21183)
We do not inherit the earth from our ancestors, we borrow it from our children. - S.M.A.R.T Person [unhandled content-type:application/pgp-signature] | |