Re: CONFIG_LD_DEAD_CODE_DATA_ELIMINATION: Section mismatch in reference from the variable via_pmu_driver to the function .init.text:pmu_init()

[Christophe LEROY]

Le 03/07/2018 à 11:40, Mathieu Malaterre a écrit :
Hi Nick,

Would you consider this a bug:

Looks more like a feature ...

In /drivers/macintosh/adb.c you have, and it's the only place 
via_pmu_driver is used.

#if defined(CONFIG_ADB_PMU) || defined(CONFIG_ADB_PMU68K)
        &via_pmu_driver,
#endif

Is one of those defined in your .config ? If not then via_pmu_driver 
gets eliminated hence nothing to warn on.


Christophe



$ 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