On 11.03.2024 09:59, Simone Ballarin wrote: > The Xen sources contain violations of MISRA C:2012 Directive 4.10 whose > headline states: > "Precautions shall be taken in order to prevent the contents of a header file > being included more than once". > > As stated in v2, the following naming convention has been estabilished: > - arch/.../include/asm/ headers -> ASM_<filename>_H > - private headers -> <dir>_<filename>_H > - asm-generic headers -> ASM_GENERIC_<filename>_H > > Since there would have been conflicting guards between architectures (which > is a violation > of the directive),
Why would this be a violation? The two sets of headers aren't use together, and any scan should only point out collisions in what's actively used, I'd hope. > there has been a need for ASM headers to specify if the inclusion guard > referred to ARM or X86. Hence it has been decided to adopt instead: > - arch/<architecture>/include/asm/<subdir>/<filename>.h -> > ASM_<architecture>_<subdir>_<filename>_H > > The subdir used is the smallest possible to avoid collisions. For example, it > has been > observed that in "xen/arch/arm/include/asm/arm32" and > "xen/arch/arm/include/asm/arm64" there > are plenty of header files with the same name, hence _ARMxx_ was added as > subdirectory. Why couldn't <arch>_<subdir> together be ARMxx there, allowing us to get away with one less name component. > There has been a need to define a standard for generated headers too: > - include/generated/<subdir>/<filename>.h-> GENERATED_<subdir>_<filename>_H > - arch/<architecture>/include/generated/asm/<filename>.h-> > <arch>_GENERATED_ASM_<name>_H > > To summarize, here are all the rules that have been applied: > - private headers -> <dir>_<filename>_H And <dir> here is the full path? I thought I had indicated before that this is going to lead to excessively long identifiers. > - asm-generic headers -> ASM_GENERIC_<filename>_H > - arch/<architecture>/include/asm/<subdir>/<filename>.h -> > ASM_<architecture>_<subdir>_<filename>_H > - include/generated/<subdir>/<filename>.h-> GENERATED_<subdir>_<filename>_H > - arch/<architecture>/include/generated/asm/<filename>.h-> > <arch>_GENERATED_ASM_<name>_H And _ASM_ is merely a precaution for stuff appearing outside of asm/ (which doesn't seem very likely)? Jan
