Re: [PATCH] x86/ACPI: Fix build error when tboot is disabled

[Jan Beulich <jbeulich@xxxxxxxx>]

On 29.04.2021 14:11, Costin Lupu wrote:
> When tboot is disabled via menuconfig we get undefined reference error for
> g_tboot_shared. This patch fixes that by disabling the causing source code
> when tboot is disabled.

There must be more to this: Our shim config also builds with tboot
disabled, without running into any build issue. Furthermore ...

> --- a/xen/arch/x86/acpi/power.c
> +++ b/xen/arch/x86/acpi/power.c
> @@ -407,6 +407,7 @@ static int acpi_get_wake_status(void)
>      return val;
>  }
>  
> +#ifdef CONFIG_TBOOT
>  static void tboot_sleep(u8 sleep_state)
>  {
>      uint32_t shutdown_type;
> @@ -451,18 +452,21 @@ static void tboot_sleep(u8 sleep_state)
>  
>      tboot_shutdown(shutdown_type);
>  }
> +#endif
>  
>  /* System is really put into sleep state by this stub */
>  acpi_status acpi_enter_sleep_state(u8 sleep_state)
>  {
>      acpi_status status;
>  
> +#ifdef CONFIG_TBOOT
>      if ( tboot_in_measured_env() )
>      {
>          tboot_sleep(sleep_state);
>          printk(XENLOG_ERR "TBOOT failed entering s3 state\n");
>          return_ACPI_STATUS(AE_ERROR);
>      }
> +#endif

... tboot_in_measured_env() already has a stub returning 0 when
!TBOOT (which is what I would have recommended instead of the
#ifdef-ary).

If there is a specific case where the compiler fails to DCE the
offending code, then you need to describe this in sufficient
detail.

Jan