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From:   Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Subject: Re: [PATCH v4 0/5] Powerpc/Watchpoint: Few important fixes
To:     Christophe Leroy <christophe.leroy@c-s.fr>
Cc:     mpe@ellerman.id.au, mikey@neuling.org, npiggin@gmail.com,
        benh@kernel.crashing.org, paulus@samba.org,
        naveen.n.rao@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org,
        linux-kernel@vger.kernel.org,
        Ravi Bangoria <ravi.bangoria@linux.ibm.com>
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 <de06dac0-3103-64ed-0e97-c2b6972c59c2@c-s.fr>
Date:   Mon, 14 Oct 2019 09:14:53 +0530
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On 10/12/19 2:21 PM, Christophe Leroy wrote:
> 
> 
> Le 10/10/2019 à 06:44, Ravi Bangoria a écrit :
>>
>>>> @Christophe, Is patch5 works for you on 8xx?
>>>>
>>>
>>> Getting the following :
>>>
>>> root@vgoip:~# ./ptrace-hwbreak
>>> test: ptrace-hwbreak
>>> tags: git_version:v5.4-rc2-710-gf0082e173fe4-dirty
>>> PTRACE_SET_DEBUGREG, WO, len: 1: Ok
>>> PTRACE_SET_DEBUGREG, WO, len: 2: Ok
>>> PTRACE_SET_DEBUGREG, WO, len: 4: Ok
>>> PTRACE_SET_DEBUGREG, WO, len: 8: Ok
>>> PTRACE_SET_DEBUGREG, RO, len: 1: Ok
>>> PTRACE_SET_DEBUGREG, RO, len: 2: Ok
>>> PTRACE_SET_DEBUGREG, RO, len: 4: Ok
>>> PTRACE_SET_DEBUGREG, RO, len: 8: Ok
>>> PTRACE_SET_DEBUGREG, RW, len: 1: Ok
>>> PTRACE_SET_DEBUGREG, RW, len: 2: Ok
>>> PTRACE_SET_DEBUGREG, RW, len: 4: Ok
>>> PTRACE_SET_DEBUGREG, RW, len: 8: Ok
>>> PPC_PTRACE_SETHWDEBUG, MODE_EXACT, WO, len: 1: Ok
>>> PPC_PTRACE_SETHWDEBUG, MODE_EXACT, RO, len: 1: Ok
>>> PPC_PTRACE_SETHWDEBUG, MODE_EXACT, RW, len: 1: Ok
>>> PPC_PTRACE_SETHWDEBUG, MODE_RANGE, DW ALIGNED, WO, len: 6: Ok
>>> PPC_PTRACE_SETHWDEBUG, MODE_RANGE, DW ALIGNED, RO, len: 6: Fail
>>> failure: ptrace-hwbreak
>>>
>>
> 
> I also tried on a 83xx (book3s/32). This one has a regular DABR :
> 
> root@vgoippro:~# ./ptrace-hwbreak
> test: ptrace-hwbreak
> tags: git_version:v5.4-rc2-710-gf0082e173fe4-dirty
> PTRACE_SET_DEBUGREG, WO, len: 1: Ok
> PTRACE_SET_DEBUGREG, WO, len: 2: Ok
> PTRACE_SET_DEBUGREG, WO, len: 4: Ok
> PTRACE_SET_DEBUGREG, WO, len: 8: Ok
> PTRACE_SET_DEBUGREG, RO, len: 1: Ok
> PTRACE_SET_DEBUGREG, RO, len: 2: Ok
> PTRACE_SET_DEBUGREG, RO, len: 4: Ok
> PTRACE_SET_DEBUGREG, RO, len: 8: Ok
> PTRACE_SET_DEBUGREG, RW, len: 1: Ok
> PTRACE_SET_DEBUGREG, RW, len: 2: Ok
> PTRACE_SET_DEBUGREG, RW, len: 4: Ok
> PTRACE_SET_DEBUGREG, RW, len: 8: Ok
> PPC_PTRACE_SETHWDEBUG, MODE_EXACT, WO, len: 1: Ok
> PPC_PTRACE_SETHWDEBUG, MODE_EXACT, RO, len: 1: Ok
> PPC_PTRACE_SETHWDEBUG, MODE_EXACT, RW, len: 1: Ok
> PPC_PTRACE_SETHWDEBUG, MODE_RANGE, DW ALIGNED, WO, len: 6: Ok
> PPC_PTRACE_SETHWDEBUG, MODE_RANGE, DW ALIGNED, RO, len: 6: Ok
> PPC_PTRACE_SETHWDEBUG, MODE_RANGE, DW ALIGNED, RW, len: 6: Ok
> PPC_PTRACE_SETHWDEBUG failed: Invalid argument

Ok. If it has the DABR _only_, creation of MODE RANGE UNALINGED breakpoint
will failed because DABR supports only 8 bytes wide breakpoint and it must
be doubleword aligned.

So this means I've to add all unaligned tests inside if (dawr) condition.

Ravi