Re: [XEN PATCH][for-4.19 v2] xen: Add SAF deviations for MISRA C:2012 Rule 7.1

[Jan Beulich <jbeulich@xxxxxxxx>]

On 20.10.2023 12:33, Nicola Vetrini wrote:
> On 20/10/2023 08:38, Jan Beulich wrote:
>> On 19.10.2023 18:34, Nicola Vetrini wrote:
>>> On 19/10/2023 17:57, Jan Beulich wrote:
>>>> On 19.10.2023 13:04, Nicola Vetrini wrote:
>>>>> --- a/automation/eclair_analysis/ECLAIR/deviations.ecl
>>>>> +++ b/automation/eclair_analysis/ECLAIR/deviations.ecl
>>>>> @@ -85,10 +85,10 @@ conform to the directive."
>>>>>  # Series 7.
>>>>>  #
>>>>>
>>>>> --doc_begin="Usage of the following constants is safe, since they 
>>>>> are
>>>>> given as-is
>>>>> -in the inflate algorithm specification and there is therefore no 
>>>>> risk
>>>>> of them
>>>>> -being interpreted as decimal constants."
>>>>> --config=MC3R1.R7.1,literals={safe,
>>>>> "^0(007|37|070|213|236|300|321|330|331|332|333|334|335|337|371)$"}
>>>>> +-doc_begin="Octal constants used as arguments to macro INSTR_ENC or
>>>>> MASK_EXTR
>>>>> +can be used, because they appear as is in specifications, manuals,
>>>>> and
>>>>> +algorithm descriptions."
>>>>> +-config=MC3R1.R7.1,reports+={safe,
>>>>> "any_area(any_loc(any_exp(macro(^(INSTR_ENC|MASK_EXTR)$))))"}
>>>>
>>>> INSTR_ENC() is a local macro in x86'es AMD SVM code. A macro of the
>>>> same
>>>> name could imo be introduced without issues in, say, Arm code. The
>>>> above
>>>> would then needlessly suppress findings there, aiui.
>>>>
>>>> MASK_EXTR() otoh is a global macro which ise used for various 
>>>> purposes.
>>>> Excluding checking there is imo going too far, too.
>>>
>>> I should have thought about it; I can simply enforce the deviation to
>>> additionally match
>>> only a specific file for each of the macros.
>>
>> That'll work for INSTR_ENC(), but not for MASK_EXTR().
>>
> 
> Why? What I'm deviating is reports due to octal constants used in 
> expressions
> that contain MASK_EXTR in their expansion if and only if these are 
> located in the
> file svm.h.
> No extra octal constant will match all these constraints.

New MASK_EXTR() uses can appear at any time, without necessarily
matching the justification.

Jan