Re: [PATCH v2 5/5] crash: Remove KEXEC_CORE_NOTE_NAME

[Dave Martin <Dave.Martin@arm.com>]

Hi,

On Sat, Jan 04, 2025 at 11:38:38PM +0900, Akihiko Odaki wrote:
> Now KEXEC_CORE_NOTE_NAME is only used at one place and it does not seem
> to provide any value anymore. Replace the remaining usage with the
> literal and remove the macro.
> 
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
>  arch/s390/kernel/crash_dump.c | 2 +-
>  include/linux/kexec.h         | 2 --
>  include/linux/vmcore_info.h   | 1 -
>  3 files changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
> index cd0c93a8fb8b..4a9817489e35 100644
> --- a/arch/s390/kernel/crash_dump.c
> +++ b/arch/s390/kernel/crash_dump.c
> @@ -253,7 +253,7 @@ static const char *nt_name(Elf64_Word type)
>  	const char *name = "LINUX";
>  
>  	if (type == NT_PRPSINFO || type == NT_PRSTATUS || type == NT_PRFPREG)
> -		name = KEXEC_CORE_NOTE_NAME;
> +		name = "CORE";

If I've understood the code here correctly, the note type is supplied
at all the nt_init() and nt_size() call sites, so instead of this hack
can we wrap those in macros that get the formal name from elf.h rather
than guessing it here?  e.g.:

#define nt_size(..., note, ...) \
	__nt_size(..., NT ## _ ## note, NN ## _ ## note, ...)

etc.

The compiler is quite likely to fold away most of the implied
duplication of code (it would be interesting to look at the compiler
output) -- but anyway, this is super-slow-path: nobody expects realtime
response when the kernel has crashed.

[...]

Cheers
---Dave