Re: [PATCH iwl-net] ice: health.c: fix compilation on gcc 7.5

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

On Wed, 5 Feb 2025 20:45:46 +0000
Simon Horman <horms@kernel.org> wrote:

> + Jiri
> 
> On Wed, Feb 05, 2025 at 11:42:12AM +0100, Przemek Kitszel wrote:
> > GCC 7 is not as good as GCC 8+ in telling what is a compile-time const,
> > and thus could be used for static storage. So we could not use variables
> > for that, no matter how much "const" keyword is sprinkled around.
> > 
> > Excerpt from the report:
> > My GCC is: gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0.
> > 
> >   CC [M]  drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.o
> > drivers/net/ethernet/intel/ice/devlink/health.c:35:3: error: initializer element is not constant
> >    ice_common_port_solutions, {ice_port_number_label}},
> >    ^~~~~~~~~~~~~~~~~~~~~~~~~
> > drivers/net/ethernet/intel/ice/devlink/health.c:35:3: note: (near initialization for 'ice_health_status_lookup[0].solution')
> > drivers/net/ethernet/intel/ice/devlink/health.c:35:31: error: initializer element is not constant
> >    ice_common_port_solutions, {ice_port_number_label}},
> >                                ^~~~~~~~~~~~~~~~~~~~~
> > drivers/net/ethernet/intel/ice/devlink/health.c:35:31: note: (near initialization for 'ice_health_status_lookup[0].data_label[0]')
> > drivers/net/ethernet/intel/ice/devlink/health.c:37:46: error: initializer element is not constant
> >    "Change or replace the module or cable.", {ice_port_number_label}},
> >                                               ^~~~~~~~~~~~~~~~~~~~~
> > drivers/net/ethernet/intel/ice/devlink/health.c:37:46: note: (near initialization for 'ice_health_status_lookup[1].data_label[0]')
> > drivers/net/ethernet/intel/ice/devlink/health.c:39:3: error: initializer element is not constant
> >    ice_common_port_solutions, {ice_port_number_label}},
> >    ^~~~~~~~~~~~~~~~~~~~~~~~~
> > 
> > Fixes: 85d6164ec56d ("ice: add fw and port health reporters")
> > Reported-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
> > Closes: https://lore.kernel.org/netdev/CY8PR11MB7134BF7A46D71E50D25FA7A989F72@CY8PR11MB7134.namprd11.prod.outlook.com
> > Signed-off-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
> > ---
> > I would really like to bump min gcc to 8.5 (RH 8 family),
> > instead of supporting old Ubuntu. However SLES 15 is also stuck with gcc 7.5 :(
> > 
> > CC: Linus Torvalds <torvalds@linux-foundation.org>
> > CC: Kees Cook <kees@kernel.org>
> > CC: Nick Desaulniers <nick.desaulniers@gmail.com>  
> 
> Hi Prezemek,
> 
> I ran into a similar problem not so long ago and I'm wondering if
> the following, based on a suggestion by Jiri Slaby, resolves your
> problem.

I'm sure I remember from somewhere that although the variables are
'static const' they have to be real variables because they can still
be patched.

Which stops you using their contents as initialisers.

Maybe I'm mis-remembering it.

	David

> 
> diff --git a/drivers/net/ethernet/intel/ice/devlink/health.c b/drivers/net/ethernet/intel/ice/devlink/health.c
> index ea40f7941259..19c3d37aa768 100644
> --- a/drivers/net/ethernet/intel/ice/devlink/health.c
> +++ b/drivers/net/ethernet/intel/ice/devlink/health.c
> @@ -25,10 +25,10 @@ struct ice_health_status {
>   * The below lookup requires to be sorted by code.
>   */
>  
> -static const char *const ice_common_port_solutions =
> +static const char ice_common_port_solutions[] =
>  	"Check your cable connection. Change or replace the module or cable. Manually set speed and duplex.";
> -static const char *const ice_port_number_label = "Port Number";
> -static const char *const ice_update_nvm_solution = "Update to the latest NVM image.";
> +static const char ice_port_number_label[] = "Port Number";
> +static const char ice_update_nvm_solution[] = "Update to the latest NVM image.";
>  
>  static const struct ice_health_status ice_health_status_lookup[] = {
>  	{ICE_AQC_HEALTH_STATUS_ERR_UNKNOWN_MOD_STRICT, "An unsupported module was detected.",
> 
> 
> Link: https://lore.kernel.org/netdev/485dbc5a-a04b-40c2-9481-955eaa5ce2e2@kernel.org/
> Link: https://git.kernel.org/netdev/net-next/c/36fb51479e3c
>