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[v4,0/5] Powerpc/Watchpoint: Few important fixes

Message ID 20190925040630.6948-1-ravi.bangoria@linux.ibm.com (mailing list archive)
Headers show
Series Powerpc/Watchpoint: Few important fixes | expand

Message

Ravi Bangoria Sept. 25, 2019, 4:06 a.m. UTC 
v3: https://lists.ozlabs.org/pipermail/linuxppc-dev/2019-July/193339.html

v3->v4:
 - Instead of considering exception as extraneous when dar is outside of
   user specified range, analyse the instruction and check for overlap
   between user specified range and actual load/store range.
 - Add selftest for the same in perf-hwbreak.c
 - Make ptrace-hwbreak.c selftest more strict by checking address in
   check_success.
 - Support for 8xx in ptrace-hwbreak.c selftest (Build tested only)
 - Rebase to powerpc/next

@Christope, Can you please check Patch 5. I've just build-tested it
with ep88xc_defconfig.

Ravi Bangoria (5):
  Powerpc/Watchpoint: Fix length calculation for unaligned target
  Powerpc/Watchpoint: Don't ignore extraneous exceptions blindly
  Powerpc/Watchpoint: Rewrite ptrace-hwbreak.c selftest
  Powerpc/Watchpoint: Add dar outside test in perf-hwbreak.c selftest
  Powerpc/Watchpoint: Support for 8xx in ptrace-hwbreak.c selftest

 arch/powerpc/include/asm/debug.h              |   1 +
 arch/powerpc/include/asm/hw_breakpoint.h      |   9 +-
 arch/powerpc/kernel/dawr.c                    |   6 +-
 arch/powerpc/kernel/hw_breakpoint.c           |  76 ++-
 arch/powerpc/kernel/process.c                 |  46 ++
 arch/powerpc/kernel/ptrace.c                  |  37 +-
 arch/powerpc/xmon/xmon.c                      |   3 +-
 .../selftests/powerpc/ptrace/perf-hwbreak.c   | 111 +++-
 .../selftests/powerpc/ptrace/ptrace-hwbreak.c | 579 +++++++++++-------
 9 files changed, 595 insertions(+), 273 deletions(-)

Comments

Ravi Bangoria Oct. 7, 2019, 6:35 a.m. UTC | #1 
On 9/25/19 9:36 AM, Ravi Bangoria wrote:
> v3: https://lists.ozlabs.org/pipermail/linuxppc-dev/2019-July/193339.html
> 
> v3->v4:
>   - Instead of considering exception as extraneous when dar is outside of
>     user specified range, analyse the instruction and check for overlap
>     between user specified range and actual load/store range.
>   - Add selftest for the same in perf-hwbreak.c
>   - Make ptrace-hwbreak.c selftest more strict by checking address in
>     check_success.
>   - Support for 8xx in ptrace-hwbreak.c selftest (Build tested only)
>   - Rebase to powerpc/next
> 
> @Christope, Can you please check Patch 5. I've just build-tested it
> with ep88xc_defconfig.

@mpe, @mikey, Any feedback?

@Christophe, Is patch5 works for you on 8xx?

Thanks,
Ravi
Christophe Leroy Oct. 9, 2019, 1:37 p.m. UTC | #2 
Le 07/10/2019 à 08:35, Ravi Bangoria a écrit :
> 
> 
> On 9/25/19 9:36 AM, Ravi Bangoria wrote:
>> v3: https://lists.ozlabs.org/pipermail/linuxppc-dev/2019-July/193339.html
>>
>> v3->v4:
>>   - Instead of considering exception as extraneous when dar is outside of
>>     user specified range, analyse the instruction and check for overlap
>>     between user specified range and actual load/store range.
>>   - Add selftest for the same in perf-hwbreak.c
>>   - Make ptrace-hwbreak.c selftest more strict by checking address in
>>     check_success.
>>   - Support for 8xx in ptrace-hwbreak.c selftest (Build tested only)
>>   - Rebase to powerpc/next
>>
>> @Christope, Can you please check Patch 5. I've just build-tested it
>> with ep88xc_defconfig.
> 
> @mpe, @mikey, Any feedback?
> 
> @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

Christophe
Ravi Bangoria Oct. 10, 2019, 4:44 a.m. UTC | #3 
>> @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
> 

Thanks Christophe. I don't have any 8xx box. I checked qemu and it seems
qemu emulation for 8xx is not yet supported. So I can't debug this. Can
you please check why it's failing?

-Ravi
Ravi Bangoria Oct. 10, 2019, 6:25 a.m. UTC | #4 
On 10/10/19 10:14 AM, Ravi Bangoria wrote:
> 
>>> @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
>>
> 
> Thanks Christophe. I don't have any 8xx box. I checked qemu and it seems
> qemu emulation for 8xx is not yet supported. So I can't debug this. Can
> you please check why it's failing?

PPC_PTRACE_SETHWDEBUG internally uses DAWR register and probably 8xx does
not emulate DAWR logic, it only uses DABR to emulate double-word watchpoint.
In that case, all testcases that uses PPC_PTRACE_SETHWDEBUG should be
disabled for 8xx. I'll change [PATCH 5] accordingly and resend.

Also, do you think I should fix hw_breakpoint_validate_len() from [PARCH 1]
for 8xx? I re-checked you recent patch* to allow any address range size for
8xx. With that patch, hw_breakpoint_validate_len() won't get called at all
for 8xx.

* Message-Id: 1ed0de54ce6021fa0fdf50e938365546a4f5e316.1566925030.git.christophe.leroy@c-s.fr

-Ravi
Christophe Leroy Oct. 10, 2019, 9:30 a.m. UTC | #5 
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
>>
> 
> Thanks Christophe. I don't have any 8xx box. I checked qemu and it seems
> qemu emulation for 8xx is not yet supported. So I can't debug this. Can
> you please check why it's failing?
> 

First issue: we get a mismatch between the parent and the child, because 
len 8 test generates two reads/writes while the parent installs the 
breakpoint only once.

Changing glvar from __u64 to unsigned long fixes the problem.

Then I get:

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, RO, len: 1: Ok
PTRACE_SET_DEBUGREG, RO, len: 2: Ok
PTRACE_SET_DEBUGREG, RO, len: 4: Ok
PTRACE_SET_DEBUGREG, RW, len: 1: Ok
PTRACE_SET_DEBUGREG, RW, len: 2: Ok
PTRACE_SET_DEBUGREG, RW, len: 4: 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: Fail
failure: ptrace-hwbreak

Which shows that PPC_PTRACE_SETHWDEBUG doesn't work in MODE_RANGE

Christophe
Christophe Leroy Oct. 12, 2019, 7:31 a.m. UTC | #6 
Le 10/10/2019 à 08:25, Ravi Bangoria a écrit :
> 
> 
> On 10/10/19 10:14 AM, Ravi Bangoria wrote:
>>
>>>> @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
>>>
>>
>> Thanks Christophe. I don't have any 8xx box. I checked qemu and it seems
>> qemu emulation for 8xx is not yet supported. So I can't debug this. Can
>> you please check why it's failing?
> 
> PPC_PTRACE_SETHWDEBUG internally uses DAWR register and probably 8xx does
> not emulate DAWR logic, it only uses DABR to emulate double-word 
> watchpoint.
> In that case, all testcases that uses PPC_PTRACE_SETHWDEBUG should be
> disabled for 8xx. I'll change [PATCH 5] accordingly and resend.

I think the MODE_EXACT ones are OK with the 8xx at the time being.

> 
> Also, do you think I should fix hw_breakpoint_validate_len() from [PARCH 1]
> for 8xx? I re-checked you recent patch* to allow any address range size for
> 8xx. With that patch, hw_breakpoint_validate_len() won't get called at all
> for 8xx.

At the time being, the 8xx emulates DABR so it has the same limitations 
as BOOK3S.
My patch needs to be rebased on top of your series and I think it needs 
some modifications, as it seems it doesn't properly handle size 1 and 
size 2 breakpoints at least.
So I think that you should leave your Patch1 as is, and I'll modify the 
validate_len() logic while rebasing my patch.

Christophe
Christophe Leroy Oct. 12, 2019, 8:51 a.m. UTC | #7 
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
failure: ptrace-hwbreak

Christophe
Ravi Bangoria Oct. 14, 2019, 3:44 a.m. UTC | #8 
On 10/12/19 1:01 PM, Christophe Leroy wrote:
> 
> 
> Le 10/10/2019 à 08:25, Ravi Bangoria a écrit :
>>
>>
>> On 10/10/19 10:14 AM, Ravi Bangoria wrote:
>>>
>>>>> @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
>>>>
>>>
>>> Thanks Christophe. I don't have any 8xx box. I checked qemu and it seems
>>> qemu emulation for 8xx is not yet supported. So I can't debug this. Can
>>> you please check why it's failing?
>>
>> PPC_PTRACE_SETHWDEBUG internally uses DAWR register and probably 8xx does
>> not emulate DAWR logic, it only uses DABR to emulate double-word watchpoint.
>> In that case, all testcases that uses PPC_PTRACE_SETHWDEBUG should be
>> disabled for 8xx. I'll change [PATCH 5] accordingly and resend.
> 
> I think the MODE_EXACT ones are OK with the 8xx at the time being.

Ok. I'll disable other tests for 8xx.

Also, I was bit wrong in above point. Actually, PPC_PTRACE_SETHWDEBUG with RANGE
breakpoint also support DABR but the length will be 8 only. So I've to change my
patch 1 also a bit (ptrace stuff). I'll resend the series with these changes.

> 
>>
>> Also, do you think I should fix hw_breakpoint_validate_len() from [PARCH 1]
>> for 8xx? I re-checked you recent patch* to allow any address range size for
>> 8xx. With that patch, hw_breakpoint_validate_len() won't get called at all
>> for 8xx.
> 
> At the time being, the 8xx emulates DABR so it has the same limitations as BOOK3S.
> My patch needs to be rebased on top of your series and I think it needs some modifications, as it seems it doesn't properly handle size 1 and size 2 breakpoints at least.
> So I think that you should leave your Patch1 as is, and I'll modify the validate_len() logic while rebasing my patch.

Sure. Thanks for helping!

Ravi
Ravi Bangoria Oct. 14, 2019, 3:44 a.m. UTC | #9 
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