On Tue, 3 Jul 2018 13:40:55 +0200 Mathieu Malaterre <ma...@debian.org> wrote:
> On Tue, Jul 3, 2018 at 11:40 AM Mathieu Malaterre <ma...@debian.org> wrote: > > > > Hi Nick, > > > > Would you consider this a bug: > > > > $ touch drivers/macintosh/via-pmu.c > > $ CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=n make ARCH=powerpc > > CROSS_COMPILE=powerpc-linux-gnu- > > ... > > LD vmlinux.o > > MODPOST vmlinux.o > > WARNING: vmlinux.o(.data+0x216018): Section mismatch in reference from > > the variable via_pmu_driver to the function .init.text:pmu_init() > > The variable via_pmu_driver references > > the function __init pmu_init() > > If the reference is valid then annotate the > > variable with __init* or __refdata (see linux/init.h) or name the variable: > > *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console > > > > While: > > > > $ touch drivers/macintosh/via-pmu.c > > $ CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y make ARCH=powerpc > > CROSS_COMPILE=powerpc-linux-gnu- > > ... > > AR init/built-in.a > > AR built-in.a > > LD vmlinux.o > > MODPOST vmlinux.o > > KSYM .tmp_kallsyms1.o > > KSYM .tmp_kallsyms2.o > > LD vmlinux > > SORTEX vmlinux > > SYSMAP System.map > > ... > > > > Thanks for comment > > Just to clarify I reverted 58935176ad17976b7a7f6ea25c0ceb2ca4308a30 > just as to reproduce a warning. So my question (rephrased): > > Is this expected that CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y inhibit > the behavior of CONFIG_DEBUG_SECTION_MISMATCH=y ? Well that's a good question actually. Section mismatch analysis is done on the throwaway vmlinux.o which is not linked with --gc-sections (and is not a final link), so the via_pmu_driver symbol should exist and be picked up. I wonder if something about the -ffunction-sections is breaking the reference detection. Thanks, Nick