Re: [PATCH] powerpc/ftrace: Enable C Version of recordmcount

[Christophe Leroy <christophe.leroy@c-s.fr>]

Le 08/05/2019 à 02:45, Michael Ellerman a écrit :
> Christophe Leroy <christophe.leroy@c-s.fr> writes:
>> Selects HAVE_C_RECORDMCOUNT to use the C version of the recordmcount
>> intead of the old Perl Version of recordmcount.
>>
>> This should improve build time. It also seems like the old Perl Version
>> misses some calls to _mcount that the C version finds.
> 
> That would make this a bug fix possibly for stable even.
> 
> Any more details on what the difference is, is it just some random
> subset of functions or some pattern?

I have not been able to identify any pattern. Will add a few details in 
the 'issue' on github.

Christophe

> 
> cheers
> 
>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>> index 2711aac24621..d87de4f9da61 100644
>> --- a/arch/powerpc/Kconfig
>> +++ b/arch/powerpc/Kconfig
>> @@ -180,6 +180,7 @@ config PPC
>>   	select HAVE_ARCH_NVRAM_OPS
>>   	select HAVE_ARCH_SECCOMP_FILTER
>>   	select HAVE_ARCH_TRACEHOOK
>> +	select HAVE_C_RECORDMCOUNT
>>   	select HAVE_CBPF_JIT			if !PPC64
>>   	select HAVE_STACKPROTECTOR		if PPC64 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r13)
>>   	select HAVE_STACKPROTECTOR		if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2)
>> -- 
>> 2.13.3