[PATCH 1/6] powerpc/powernv/smp: Fix spurious DBG() warning

[Michael Ellerman]

Joel Stanley <joel at jms.id.au> writes:
> On Tue, 4 Aug 2020 at 00:57, Oliver O'Halloran <oohall at gmail.com> wrote:
>>
>> When building with W=1 we get the following warning:
>>
>>  arch/powerpc/platforms/powernv/smp.c: In function ‘pnv_smp_cpu_kill_self’:
>>  arch/powerpc/platforms/powernv/smp.c:276:16: error: suggest braces around
>>         empty body in an ‘if’ statement [-Werror=empty-body]
>>    276 |      cpu, srr1);
>>        |                ^
>>  cc1: all warnings being treated as errors
>>
>> The full context is this block:
>>
>>  if (srr1 && !generic_check_cpu_restart(cpu))
>>         DBG("CPU%d Unexpected exit while offline srr1=%lx!\n",
>>                         cpu, srr1);
>>
>> When building with DEBUG undefined DBG() expands to nothing and GCC emits
>> the warning due to the lack of braces around an empty statement.
>>
>> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
>> ---
>> We could add the braces too. That might even be better since it's a multi-line
>> if block even though it's only a single statement.
>
> Or you could put it all on one line, now that our 120 line overlords
> have taken over.

Yeah I think that one may as well be one line.

> Reviewed-by: Joel Stanley <joel at jms.id.au>
>
> Messy:
>
> $ git grep "define DBG(" arch/powerpc/ |grep -v print
> arch/powerpc/kernel/crash_dump.c:#define DBG(fmt...)
> arch/powerpc/kernel/iommu.c:#define DBG(...)
> arch/powerpc/kernel/legacy_serial.c:#define DBG(fmt...) do { } while(0)
> arch/powerpc/kernel/prom.c:#define DBG(fmt...)
..

Yeah, gross old cruft.

The vast majority of those should just be replaced with pr_devel()
and/or pr_debug().

The pnv_smp_cpu_kill_self() case is one where we probably do want to
stick with udbg_printf(), because I don't think it's kosher to call
printk() from an offline CPU.

cheers