linux-kernel - Re: [PATCH v2 07/16] powerpc/watchpoint: Get watchpoint count dynamically while disabling them

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Message-Id: <299bf5b6-a293-aa59-b27a-04b00ef7ea2c@linux.ibm.com>
Date:   Wed, 1 Apr 2020 14:49:48 +0530
From:   Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
To:     Christophe Leroy <christophe.leroy@....fr>
Cc:     mpe@...erman.id.au, mikey@...ling.org, apopple@...ux.ibm.com,
        paulus@...ba.org, npiggin@...il.com,
        naveen.n.rao@...ux.vnet.ibm.com, peterz@...radead.org,
        jolsa@...nel.org, oleg@...hat.com, fweisbec@...il.com,
        mingo@...nel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org,
        Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
Subject: Re: [PATCH v2 07/16] powerpc/watchpoint: Get watchpoint count
 dynamically while disabling them



On 4/1/20 12:02 PM, Christophe Leroy wrote:
> 
> 
> Le 01/04/2020 à 08:13, Ravi Bangoria a écrit :
>> Instead of disabling only one watchpoint, get num of available
>> watchpoints dynamically and disable all of them.
>>
>> Signed-off-by: Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
>> ---
>>   arch/powerpc/include/asm/hw_breakpoint.h | 15 +++++++--------
>>   1 file changed, 7 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h
>> index 4e4976c3248b..fae33c729ba9 100644
>> --- a/arch/powerpc/include/asm/hw_breakpoint.h
>> +++ b/arch/powerpc/include/asm/hw_breakpoint.h
>> @@ -78,14 +78,13 @@ extern void ptrace_triggered(struct perf_event *bp,
>>               struct perf_sample_data *data, struct pt_regs *regs);
>>   static inline void hw_breakpoint_disable(void)
>>   {
>> -    struct arch_hw_breakpoint brk;
>> -
>> -    brk.address = 0;
>> -    brk.type = 0;
>> -    brk.len = 0;
>> -    brk.hw_len = 0;
>> -    if (ppc_breakpoint_available())
>> -        __set_breakpoint(&brk, 0);
>> +    int i;
>> +    struct arch_hw_breakpoint null_brk = {0};
> 
> Those declaration should be in the block unsigned them below.
> 
>> +
>> +    if (ppc_breakpoint_available()) {
>> +        for (i = 0; i < nr_wp_slots(); i++)
>> +            __set_breakpoint(&null_brk, i);
>> +    }
> 
> I would have had a preference to the following, but that's detail I guess:
> 
>      int i;
>      struct arch_hw_breakpoint null_brk = {0};
> 
>      if (!ppc_breakpoint_available())
>          return;
> 
>      for (i = 0; i < nr_wp_slots(); i++)
>          __set_breakpoint(&null_brk, i);

This looks more better. Will change it.

Ravi