Re: [PATCH 1/1] ACPI: Fix building with GCC 15

[David Laight <david.laight.linux@gmail.com>]

On Thu, 13 Feb 2025 16:46:56 +0100
Ard Biesheuvel <ardb@kernel.org> wrote:

> On Tue, 21 Jan 2025 at 22:42, Brahmajit Das <brahmajit.xyz@gmail.com> wrote:
> >
> > Building with GCC 15 results in the following build error:
> >
> > ...
> >   CC      drivers/acpi/tables.o
> > In file included from ./include/acpi/actbl.h:371,
> >                  from ./include/acpi/acpi.h:26,
> >                  from ./include/linux/acpi.h:26,
> >                  from drivers/acpi/tables.c:19:
> > ./include/acpi/actbl1.h:30:33: error: initializer-string for array of ‘char’ is too long [-Werror=unterminated-string-initialization]
> >    30 | #define ACPI_SIG_BERT           "BERT"  /* Boot Error Record Table */
> >       |                                 ^~~~~~
> > drivers/acpi/tables.c:400:9: note: in expansion of macro ‘ACPI_SIG_BERT’
> >   400 |         ACPI_SIG_BERT, ACPI_SIG_BGRT, ACPI_SIG_CPEP, ACPI_SIG_ECDT,
> >       |         ^~~~~~~~~~~~~
> > ./include/acpi/actbl1.h:31:33: error: initializer-string for array of ‘char’ is too long [-Werror=unterminated-string-initialization]
> >    31 | #define ACPI_SIG_BGRT           "BGRT"  /* Boot Graphics Resource Table */
> >       |                                 ^~~~~~
> > drivers/acpi/tables.c:400:24: note: in expansion of macro ‘ACPI_SIG_BGRT’
> >   400 |         ACPI_SIG_BERT, ACPI_SIG_BGRT, ACPI_SIG_CPEP, ACPI_SIG_ECDT,
> >       |                        ^~~~~~~~~~~~~
> > ./include/acpi/actbl1.h:34:33: error: initializer-string for array of ‘char’ is too long [-Werror=unterminated-string-initialization]
> >    34 | #define ACPI_SIG_CPEP           "CPEP"  /* Corrected Platform Error Polling table */
> > ...
> >
> > This is due to GCC having enabled
> > -Werror=unterminated-string-initialization[0] by default. To work around
> > this build time error we're modifying the size of table_sigs from
> > table_sigs[][ACPI_NAMESEG_SIZE] to table_sigs[][ACPI_NAMESEG_SIZE + 1].
> > This ensures space for NUL, thus satisfying GCC.
> >
> > [0]: https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wno-unterminated-string-initialization
> >
> > Signed-off-by: Brahmajit Das <brahmajit.xyz@gmail.com>
> > ---
> >  drivers/acpi/tables.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
> > index 9e1b01c35070..5a6524eb79d8 100644
> > --- a/drivers/acpi/tables.c
> > +++ b/drivers/acpi/tables.c
> > @@ -396,7 +396,7 @@ static u8 __init acpi_table_checksum(u8 *buffer, u32 length)
> >  }
> >
> >  /* All but ACPI_SIG_RSDP and ACPI_SIG_FACS: */
> > -static const char table_sigs[][ACPI_NAMESEG_SIZE] __initconst = {
> > +static const char table_sigs[][ACPI_NAMESEG_SIZE + 1] __initconst = {
> >         ACPI_SIG_BERT, ACPI_SIG_BGRT, ACPI_SIG_CPEP, ACPI_SIG_ECDT,
> >         ACPI_SIG_EINJ, ACPI_SIG_ERST, ACPI_SIG_HEST, ACPI_SIG_MADT,
> >         ACPI_SIG_MSCT, ACPI_SIG_SBST, ACPI_SIG_SLIT, ACPI_SIG_SRAT,  
> 
> Please add the __nonstring attribute instead.

That doesn't fix initialisers.
There is a gcc bug about it (and a patch)...

	David