72 lines
2.8 KiB
Markdown
72 lines
2.8 KiB
Markdown
# MISRA Compliance
|
|||
|
|||
FreeRTOS-Kernel conforms to [MISRA C:2012](https://www.misra.org.uk/misra-c)
|
|||
guidelines, with the deviations listed below. Compliance is checked with
|
|||
Coverity static analysis. Since the FreeRTOS kernel is designed for
|
|||
small-embedded devices, it needs to have a very small memory footprint and
|
|||
has to be efficient. To achieve that and to increase the performance, it
|
|||
deviates from some MISRA rules. The specific deviations, suppressed inline,
|
|||
are listed below.
|
|||
|
|||
Additionally, [MISRA configuration](#misra-configuration) contains project
|
|||
wide deviations.
|
|||
|
|||
### Suppressed with Coverity Comments
|
|||
To find the violation references in the source files run grep on the source code
|
|||
with ( Assuming rule 8.4 violation; with justification in point 1 ):
|
|||
```
|
|||
grep 'MISRA Ref 8.4.1' . -rI
|
|||
```
|
|||
|
|||
#### Rule 8.4
|
|||
|
|||
_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.
|
|||
|
|||
### MISRA configuration
|
|||
|
|||
Copy below content to `misra.conf` to run Coverity on FreeRTOS-Kernel.
|
|||
|
|||
```
|
|||
// MISRA C-2012 Rules
|
|||
{
|
|||
version : "2.0",
|
|||
standard : "c2012",
|
|||
title: "Coverity MISRA Configuration",
|
|||
deviations : [
|
|||
// Disable the following rules.
|
|||
{
|
|||
deviation: "Directive 4.8",
|
|||
reason: "HeapRegion_t and HeapStats_t are used only in heap files but declared in portable.h which is included in multiple source files. As a result, these definitions appear in multiple source files where they are not used."
|
|||
},
|
|||
{
|
|||
deviation: "Directive 4.9",
|
|||
reason: "FreeRTOS-Kernel is optimised to work on small micro-controllers. To achieve that, function-like macros are used."
|
|||
},
|
|||
{
|
|||
deviation: "Rule 1.2",
|
|||
reason: "The __attribute__ tags are used via macros which are defined in port files."
|
|||
},
|
|||
{
|
|||
deviation: "Rule 3.1",
|
|||
reason: "We post HTTP links in code comments which contain // inside comments blocks."
|
|||
},
|
|||
{
|
|||
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."
|
|||
}
|
|||
]
|
|||
}
|
|||
```
|
