Re: [PATCH] common/efi: deviate Rule 2.1 violation in read_file()

[Dmytro Prokopchuk1 <dmytro_prokopchuk1@epam.com>]

On 8/21/25 13:33, Jan Beulich wrote:
> On 20.08.2025 20:05, Dmytro Prokopchuk1 wrote:
>> --- a/xen/common/efi/boot.c
>> +++ b/xen/common/efi/boot.c
>> @@ -852,7 +852,7 @@ static bool __init read_file(EFI_FILE_HANDLE dir_handle, CHAR16 *name,
>>       PrintErr(L" failed for ");
>>       PrintErrMesg(name, ret);
>>   
>> -    /* not reached */
>> +    /* SAF-15-safe deliberately unreachable code */
>>       return false;
>>   }
> 
> Much better (even if not tagged as v2). Yet then, did you consider
> alternatives? For example, with PrintErrMesg() properly annotated "noreturn",
> I'd kind of expect compilers to not object to the omission of the "return"
> statement here. This would then let us get away without a new SAF comment.
> While you explain in the SAF text why you retain the statement, I'm not
> convinced of code clarity suffering if it was deleted, as long as a suitable
> comment is still there. If PrintErrMesg() lost its "noreturn", surely
> compilers would then diagnose the lack of "return".
> 
> Jan

Sure, the next version will be v3.
Actually, the PrintErrMesg() already has property 'noreturn'.
And it really gives an alternative way: remove 'return false;' from the 
function read_file() (leaving comment there).

With that change Misra is "happy".

In case of removing 'noreturn' attribute from PrintErrMesg() function 
compiler will detect that:
arch/arm/efi/boot.c: In function ‘read_file’:
arch/arm/efi/boot.c:854:1: error: control reaches end of non-void 
function [-Werror=return-type]
  }
  ^

Is it OK to prepare such ^ patch?

Dmytro.