[U-Boot] [PATCH 1/1] efi_loader: allow return value in EFI_CALL

[Rob Clark]

On Tue, Aug 15, 2017 at 3:42 PM, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> Macro EFI_CALL was introduced to call an UEFI function.
> Unfortunately is did not support return values.
> Most UEFI functions have a return value.
>
> So let's rename EFI_CALL to EFI_CALL_VOID and introduce a
> new EFI_CALL macro that supports return values.
>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> ---
>  include/efi_loader.h          | 16 ++++++++++++++--
>  lib/efi_loader/efi_boottime.c |  3 ++-
>  2 files changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/include/efi_loader.h b/include/efi_loader.h
> index 037cc7c543..1cee10ea0c 100644
> --- a/include/efi_loader.h
> +++ b/include/efi_loader.h
> @@ -41,9 +41,21 @@ const char *__efi_nesting_dec(void);
>         })
>
>  /*
> - * Callback into UEFI world from u-boot:
> + * Call non-void UEFI function from u-boot and retrieve return value:
>   */
> -#define EFI_CALL(exp) do { \
> +#define EFI_CALL(exp) ({ \
> +       debug("%sEFI: Call: %s\n", __efi_nesting_inc(), #exp); \
> +       assert(__efi_exit_check()); \
> +       typeof(exp) r = exp; \
> +       assert(__efi_entry_check()); \
> +       debug("%sEFI: Return From: %s\n", __efi_nesting_dec(), #exp); \
> +       r; \
> +})
> +

So, I had considered something similar, for the purposes of being able
to print return value, but in the end decided that the EFI_EXIT()
print was usually sufficient (except in cases where you enable DEBUG
in some files but not others), and opted for the simpler MACRO(ret =
somecall()) approach.. also the longer macro name makes not going over
80 chars harder in some cases ;-)

I don't really feel strongly one way or another.. but I guess if we do
this we might as well add the return value (cast to u64 and print as
hex to cover both ptrs and efi_status_t?) to the "Return From" debug
print.

BR,
-R

> +/*
> + * Call void UEFI function world from u-boot:
> + */
> +#define EFI_CALL_VOID(exp) do { \
>         debug("%sEFI: Call: %s\n", __efi_nesting_inc(), #exp); \
>         assert(__efi_exit_check()); \
>         exp; \
> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
> index 43f32385fa..6489a32505 100644
> --- a/lib/efi_loader/efi_boottime.c
> +++ b/lib/efi_loader/efi_boottime.c
> @@ -158,7 +158,8 @@ void efi_signal_event(struct efi_event *event)
>                 return;
>         event->signaled = 1;
>         if (event->type & EVT_NOTIFY_SIGNAL) {
> -               EFI_CALL(event->notify_function(event, event->notify_context));
> +               EFI_CALL_VOID(event->notify_function(event,
> +                                                    event->notify_context));
>         }
>  }
>
> --
> 2.14.1
>