docs/misra: add R11.1 R11.2 R11.3 R11.6

Add MISRA C Rules 11.1, 11.2, 11.3, 11.6 as discussed.

Explicitly add in the notes that conversions to integer types are
permitted if the destination type has enough bits to hold the entire
value. GCC gives enough guarantees in terms of preserving the bit
content in such situations.

Also allow for bool conversions (e.g. to check if a function point is
valid).

Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

docs/misra/rules.rst

@@ -383,6 +383,36 @@ maintainers if you want to suggest a change.
 
        CFLAGS="-Warith-conversion -Wno-error=arith-conversion" make -C xen
 
+   * - `Rule 11.1 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_11_01.c>`_
+     - Required
+     - Conversions shall not be performed between a pointer to a
+       function and any other type
+     - All conversions to integer types are permitted if the destination
+       type has enough bits to hold the entire value. Conversions to
+       bool and void* are permitted.
+
+   * - `Rule 11.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_11_02.c>`_
+     - Required
+     - Conversions shall not be performed between a pointer to an
+       incomplete type and any other type
+     - All conversions to integer types are permitted if the destination
+       type has enough bits to hold the entire value. Conversions to
+       bool and void* are permitted.
+
+   * - `Rule 11.3 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_11_03.c>`_
+     - Required
+     - A cast shall not be performed between a pointer to object type
+       and a pointer to a different object type
+     -
+
+   * - `Rule 11.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_11_06.c>`_
+     - Required
+     - A cast shall not be performed between pointer to void and an
+       arithmetic type
+     - All conversions to integer types are permitted if the destination
+       type has enough bits to hold the entire value. Conversions to
+       bool are permitted.
+
    * - `Rule 11.7 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_11_07.c>`_
      - Required
      - A cast shall not be performed between pointer to object and a noninteger arithmetic type