Re: [PATCH v2 2/3] selftests/powerpc: Add test for real address error handling

[Ganesh <ganeshgr@linux.ibm.com>]

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On 8/26/21 8:57 AM, Michael Ellerman wrote:
> Ganesh <ganeshgr@linux.ibm.com> writes:
>> On 8/24/21 6:18 PM, Michael Ellerman wrote:
>>
>>> Ganesh Goudar <ganeshgr@linux.ibm.com> writes:
>>>> Add test for real address or control memory address access
>>>> error handling, using NX-GZIP engine.
>>>>
>>>> The error is injected by accessing the control memory address
>>>> using illegal instruction, on successful handling the process
>>>> attempting to access control memory address using illegal
>>>> instruction receives SIGBUS.
>>> ...
>>>
>>>> diff --git a/tools/testing/selftests/powerpc/mce/inject-ra-err.sh b/tools/testing/selftests/powerpc/mce/inject-ra-err.sh
>>>> new file mode 100755
>>>> index 000000000000..3633cdc651a1
>>>> --- /dev/null
>>>> +++ b/tools/testing/selftests/powerpc/mce/inject-ra-err.sh
>>>> @@ -0,0 +1,18 @@
>>>> +#!/bin/bash
>>>> +# SPDX-License-Identifier: GPL-2.0-or-later
>>>> +
>>>> +if [[ ! -w /dev/crypto/nx-gzip ]]; then
>>>> +	echo "WARN: Can't access /dev/crypto/nx-gzip, skipping"
>>>> +	exit 0
>>>> +fi
>>>> +
>>>> +timeout 5 ./inject-ra-err
>>>> +
>>>> +# 128 + 7 (SIGBUS) = 135, 128 is a exit code with special meaning.
>>>> +if [ $? -ne 135 ]; then
>>>> +	echo "FAILED: Real address or Control memory access error not handled"
>>>> +	exit $?
>>>> +fi
>>>> +
>>>> +echo "OK: Real address or Control memory access error is handled"
>>>> +exit 0
>>> I don't think we really need the shell script, we should be able to do
>>> all that in the C code.
>>>
>>> Can you try this?
>> it works!, We need to set timeout, with 120 sec timeout we may flood the dmesg.
> Hmm. Does it keep faulting? The regs->nip += 4 is meant to avoid that.

Yes, it keeps faulting, if we fail to handle and not send SIGBUS to the process.

>
> cheers

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