Suppress MISRA C:2012 rule 11.5 deviations (#878)

* Suppress MISRA C:2012 rule 11.5 deviations by comment also remove this rule in global config

---------

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
Co-authored-by: Ubuntu <ubuntu@ip-172-31-34-245.ap-northeast-1.compute.internal>
Co-authored-by: Rahul Kar <karahulx@amazon.com>
Co-authored-by: Soren Ptak <ptaksoren@gmail.com>
Co-authored-by: Gaurav-Aggarwal-AWS <33462878+aggarg@users.noreply.github.com>
Co-authored-by: Gaurav Aggarwal <aggarg@amazon.com>
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chinglee-iot 2023-12-06 09:51:52 +08:00 committed by GitHub
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commit 84c0047ccd
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7 changed files with 191 additions and 76 deletions

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@ -20,34 +20,72 @@ grep 'MISRA Ref 8.4.1' . -rI
#### Rule 8.4
MISRA C:2012 Rule 8.4: A compatible declaration shall be visible when an
object or function with external linkage is defined.
_Ref 8.4.1_
- MISRA C:2012 Rule 8.4: A compatible declaration shall be visible when an
object or function with external linkage is defined.
This rule requires that a compatible declaration is made available
in a header file when an object with external linkage is defined.
pxCurrentTCB(s) is defined with external linkage but it is only
referenced from the assembly code in the port files. Therefore, adding
a declaration in header file is not useful as the assembly code will
still need to declare it separately.
- This rule requires that a compatible declaration is made available
in a header file when an object with external linkage is defined.
pxCurrentTCB(s) is defined with external linkage but it is only
referenced from the assembly code in the port files. Therefore, adding
a declaration in header file is not useful as the assembly code will
still need to declare it separately.
#### Rule 11.3
_Ref 11.3.1_
MISRA C:2012 Rule 11.3: A cast shall not be performed between a pointer to
object type and a pointer to a different object type.
- MISRA C:2012 Rule 11.3: A cast shall not be performed between a pointer to
object type and a pointer to a different object type.
This rule prohibits casting a pointer to object into a pointer to a
different object because it may result in an incorrectly aligned pointer,
leading to undefined behavior. Even if the casting produces a correctly
aligned pointer, the behavior may be still undefined if the pointer is
used to access an object. FreeRTOS deliberately creates external aliases
for all the kernel object types (StaticEventGroup_t, StaticQueue_t,
StaticStreamBuffer_t, StaticTimer_t and StaticTask_t) for data hiding
purposes. The internal object types and the corresponding external
aliases are guaranteed to have the same size and alignment which is
checked using configASSERT.
_Ref 11.3.1_
- This rule prohibits casting a pointer to object into a pointer to a
different object because it may result in an incorrectly aligned pointer,
leading to undefined behavior. Even if the casting produces a correctly
aligned pointer, the behavior may be still undefined if the pointer is
used to access an object. FreeRTOS deliberately creates external aliases
for all the kernel object types (StaticEventGroup_t, StaticQueue_t,
StaticStreamBuffer_t, StaticTimer_t and StaticTask_t) for data hiding
purposes. The internal object types and the corresponding external
aliases are guaranteed to have the same size and alignment which is
checked using configASSERT.
#### Rule 11.5
MISRA C:2012 Rule 11.5: A conversion should not be performed from pointer to
void into pointer to object.
This rule prohibits conversion of a pointer to void into a pointer to
object because it may result in an incorrectly aligned pointer leading
to undefined behavior.
_Ref 11.5.1_
- The memory blocks returned by pvPortMalloc() are guaranteed to meet the
architecture alignment requirements specified by portBYTE_ALIGNMENT.
The casting of the pointer to void returned by pvPortMalloc() is,
therefore, safe because it is guaranteed to be aligned.
_Ref 11.5.2_
- The conversion from a pointer to void into a pointer to EventGroup_t is
safe because it is a pointer to EventGroup_t, which is returned to the
application at the time of event group creation for data hiding
purposes.
_Ref 11.5.3_
- The conversion from a pointer to void in list macros for list item owner
is safe because the type of the pointer stored and retrieved is the
same.
_Ref 11.5.4_
- The conversion from a pointer to void into a pointer to EventGroup_t is
safe because it is a pointer to EventGroup_t, which is passed as a
parameter to the xTimerPendFunctionCallFromISR API when the callback is
pended.
_Ref 11.5.5_
- The conversion from a pointer to void into a pointer to uint8_t is safe
because data storage buffers are implemented as uint8_t arrays for the
ease of sizing, alignment and access.
### MISRA configuration
@ -81,10 +119,6 @@ Copy below content to `misra.conf` to run Coverity on FreeRTOS-Kernel.
{
deviation: "Rule 8.7",
reason: "API functions are not used by the library outside of the files they are defined; however, they must be externally visible in order to be used by an application."
},
{
deviation: "Rule 11.5",
reason: "Allow casts from `void *`. List owner, pvOwner, is stored as `void *` and are cast to various types for use in functions."
}
]
}