linux-kernel - Re: [PATCH] powerpc/watchpoint: Don't call dar_within

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Message-Id: <22698949-553b-c15d-27b1-983d3fb47507@linux.ibm.com>
Date:   Sat, 22 Feb 2020 18:46:55 +0530
From:   Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
To:     Christophe Leroy <christophe.leroy@....fr>
Cc:     mpe@...erman.id.au, mikey@...ling.org,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
Subject: Re: [PATCH] powerpc/watchpoint: Don't call dar_within_range() for
 Book3S



On 2/22/20 4:56 PM, Christophe Leroy wrote:
> 
> 
> On 02/22/2020 08:20 AM, Ravi Bangoria wrote:
>> DAR is set to the first byte of overlap between actual access and
>> watched range at DSI on Book3S processor. But actual access range
>> might or might not be within user asked range. So for Book3S, it
>> must not call dar_within_range().
>>
>> This revert portion of commit 39413ae00967 ("powerpc/hw_breakpoints:
>> Rewrite 8xx breakpoints to allow any address range size.").
>>
>> Before patch:
>>    # ./tools/testing/selftests/powerpc/ptrace/perf-hwbreak
>>    ...
>>    TESTED: No overlap
>>    FAILED: Partial overlap: 0 != 2
>>    TESTED: Partial overlap
>>    TESTED: No overlap
>>    FAILED: Full overlap: 0 != 2
>>    failure: perf_hwbreak
>>
>> After patch:
>>    TESTED: No overlap
>>    TESTED: Partial overlap
>>    TESTED: Partial overlap
>>    TESTED: No overlap
>>    TESTED: Full overlap
>>    success: perf_hwbreak
>>
>> Fixes: 39413ae00967 ("powerpc/hw_breakpoints: Rewrite 8xx breakpoints to allow any address range size.")
> 
> Oh, this seems to have been introduced by 27985b2a640e ("powerpc/watchpoint: Don't ignore extraneous exceptions blindly").
> 
> I must have lost it through a rebase as we were doing our series approximately at the same time, sorry for that.
> 
> Reviewed-by: Christophe Leroy <christophe.leroy@....fr>

No worries. Thanks for the review :)

Ravi