Messages in this thread |  | | Date | Fri, 6 Aug 2021 09:26:43 -0500 | From | Segher Boessenkool <> | Subject | Re: [RFC PATCH 1/4] powerpc: Optimize register usage for esr register |
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On Fri, Aug 06, 2021 at 04:53:14PM +1000, Michael Ellerman wrote: > But I'm not sure about the use of anonymous unions in UAPI headers. Old > compilers don't support them, so there's a risk of breakage.
More precisely, it exists only since C11, so even with all not-so-ancient compilers it will not work if the user uses (say) -std=c99, which still is popular.
> I'd rather we didn't touch the uapi version.
Yeah.
> > - err = ___do_page_fault(regs, regs->dar, regs->dsisr); > > + if (IS_ENABLED(CONFIG_4xx) || IS_ENABLED(CONFIG_BOOKE)) > > + err = ___do_page_fault(regs, regs->dar, regs->esr); > > + else > > + err = ___do_page_fault(regs, regs->dar, regs->dsisr); > > As Christophe said, I don't thinks this is an improvement. > > It makes the code less readable. If anyone is confused about what is > passed to ___do_page_fault() they can either read the comment above it, > or look at the definition of pt_regs to see that esr and dsisr share > storage.
Esp. since the affected platforms are legacy, yup.
Segher
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