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Subject: Re: [PATCH 4/5] Powerpc/hw-breakpoint: Optimize disable path
To:     Christophe Leroy <christophe.leroy@c-s.fr>
Cc:     mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org,
        mikey@neuling.org, linuxppc-dev@lists.ozlabs.org,
        linux-kernel@vger.kernel.org, npiggin@gmail.com,
        naveen.n.rao@linux.vnet.ibm.com,
        Ravi Bangoria <ravi.bangoria@linux.ibm.com>
References: <20190618042732.5582-1-ravi.bangoria@linux.ibm.com>
 <20190618042732.5582-5-ravi.bangoria@linux.ibm.com>
 <6e7c6054-b152-40db-c7d3-89901949460f@c-s.fr>
From:   Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Date:   Wed, 19 Jun 2019 11:44:50 +0530
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On 6/18/19 12:01 PM, Christophe Leroy wrote:
>> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
>> index f002d2ffff86..265fac9fb3a4 100644
>> --- a/arch/powerpc/kernel/process.c
>> +++ b/arch/powerpc/kernel/process.c
>> @@ -793,10 +793,22 @@ static inline int set_dabr(struct arch_hw_breakpoint *brk)
>>       return __set_dabr(dabr, dabrx);
>>   }
>>   +static int disable_dawr(void)
>> +{
>> +    if (ppc_md.set_dawr)
>> +        return ppc_md.set_dawr(0, 0);
>> +
>> +    mtspr(SPRN_DAWRX, 0);
> 
> And SPRN_DAWR ?

Setting DAWRx with 0 should be enough to disable the breakpoint.