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Re: [XEN PATCH] automation/eclair_analysis: address violations of Rule 18.2


  • To: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
  • From: Jan Beulich <jbeulich@xxxxxxxx>
  • Date: Fri, 6 Sep 2024 08:03:46 +0200
  • Autocrypt: addr=jbeulich@xxxxxxxx; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL
  • Cc: sstabellini@xxxxxxxxxx, michal.orzel@xxxxxxx, xenia.ragiadakou@xxxxxxx, ayan.kumar.halder@xxxxxxx, consulting@xxxxxxxxxxx, Simone Ballarin <simone.ballarin@xxxxxxxxxxx>, Doug Goldstein <cardoe@xxxxxxxxxx>, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Julien Grall <julien@xxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
  • Delivery-date: Fri, 06 Sep 2024 06:03:56 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 05.09.2024 18:37, Nicola Vetrini wrote:
> MISRA C Rule 18.2 states: "Subtraction between pointers shall
> only be applied to pointers that address elements of the same array".
> 
> Subtractions between pointer where at least one symbol is a
> symbol defined by the linker are safe and thus deviated, because
> the compiler cannot exploit the undefined behaviour that would
> arise from violating the rules in this case.
> 
> To create an ECLAIR configuration that contains the list of
> linker-defined symbols, the script "linker-symbols.sh" is used
> after a build of xen (without static analysis) is performed.
> The generated file "linker_symbols.ecl" is then used as part of the
> static analysis configuration.
> 
> Additional changes to the ECLAIR integration are:
> - perform a build of xen without static analysis during prepare.sh
> - run the scripts to generated ECL configuration during the prepare.sh,
>   rather than analysis.sh
> - export ECLAIR_PROJECT_ROOT earlier, to allow such generation
> 
> Additionally, the macro page_to_mfn performs a subtraction that is safe,
> so its uses are deviated.
> 
> No functional changes.
> 
> Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
> ---
> Macro page_to_pdx is also the cause of some caution reports:
> perhaps that should be deviated as well, since its definition is very
> similar to page_to_mfn.
> 
> Relevant CI runs:
> 
> - arm64: 
> https://saas.eclairit.com:3787/fs/var/local/eclair/xen-project.ecdf/xen-project/people/bugseng/xen/ECLAIR_normal/MC3R1.R18.2/ARM64/7754928624/PROJECT.ecd;/by_service/MC3R1.R18.2.html
> 
> - x86_64: 
> https://saas.eclairit.com:3787/fs/var/local/eclair/xen-project.ecdf/xen-project/people/bugseng/xen/ECLAIR_normal/MC3R1.R18.2/X86_64/7754928613/PROJECT.ecd;/by_service/MC3R1.R18.2.html
> - x86_64 (without page_to_pdx reports): 
> https://saas.eclairit.com:3787/fs/var/local/eclair/xen-project.ecdf/xen-project/people/bugseng/xen/ECLAIR_normal/MC3R1.R18.2/X86_64/7754928613/PROJECT.ecd;/by_service/MC3R1.R18.2.html#{"select":true,"selection":{"hiddenAreaKinds":[],"hiddenSubareaKinds":[],"show":false,"selector":{"enabled":true,"negated":false,"kind":0,"domain":"message","inputs":[{"enabled":true,"text":"^.*expanded
>  from macro `page_to_pdx'"}]}}}
> ---
>  automation/eclair_analysis/ECLAIR/analyze.sh  |  6 ----
>  .../eclair_analysis/ECLAIR/deviations.ecl     | 11 +++++++
>  .../eclair_analysis/ECLAIR/generate_ecl.sh    |  3 ++
>  .../ECLAIR/generate_linker_symbols.sh         | 31 +++++++++++++++++++
>  automation/eclair_analysis/prepare.sh         |  6 +++-
>  automation/scripts/eclair                     |  3 ++
>  docs/misra/deviations.rst                     | 10 ++++++
>  7 files changed, 63 insertions(+), 7 deletions(-)
>  create mode 100755 
> automation/eclair_analysis/ECLAIR/generate_linker_symbols.sh

Nit: Dashes instead of underscores in names of new files, please.

Jan



 


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