Re: [PATCH] s390: Add '-std=gnu11' to decompressor and purgatory CFLAGS

[Heiko Carstens]

On Wed, Jan 22, 2025 at 07:54:27PM -0700, Nathan Chancellor wrote:
> GCC changed the default C standard dialect from gnu17 to gnu23,
> which should not have impacted the kernel because it explicitly requests
> the gnu11 standard in the main Makefile. However, there are certain
> places in the s390 code that use their own CFLAGS without a '-std='
> value, which break with this dialect change because of the kernel's own
> definitions of bool, false, and true conflicting with the C23 reserved
> keywords.
> 
>   include/linux/stddef.h:11:9: error: cannot use keyword 'false' as enumeration constant
>      11 |         false   = 0,
>         |         ^~~~~
>   include/linux/stddef.h:11:9: note: 'false' is a keyword with '-std=c23' onwards
>   include/linux/types.h:35:33: error: 'bool' cannot be defined via 'typedef'
>      35 | typedef _Bool                   bool;
>         |                                 ^~~~
>   include/linux/types.h:35:33: note: 'bool' is a keyword with '-std=c23' onwards
> 
> Add '-std=gnu11' to the decompressor and purgatory CFLAGS to eliminate
> these errors and make the C standard version of these areas match the
> rest of the kernel.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
> ---

Thanks!
Tested-by: Heiko Carstens <hca@xxxxxxxxxxxxx>

Alexander, can you pick this up, please?

> I only see one other error in various files with a recent GCC 15.0.1
> snapshot, which I can eliminate by dropping the version part of the
> condition for CONFIG_GCC_ASM_FLAG_OUTPUT_BROKEN. Is this a regression of
> the fix for the problem of GCC 14.2.0 or is something else doing on
> here?
> 
>   arch/s390/include/asm/bitops.h: Assembler messages:
>   arch/s390/include/asm/bitops.h:60: Error: operand 1: syntax error; missing ')' after base register
>   arch/s390/include/asm/bitops.h:60: Error: operand 2: syntax error; ')' not allowed here
>   arch/s390/include/asm/bitops.h:60: Error: junk at end of line: `,4'

That is I bug I recently introduced.
The patch below fixes that. Thanks for reporting!