Re: [PATCH 11/35] MdeModulePkg: document workaround for EFI_RUNTIME_EVENT_ENTRY PI spec bug

["Dandan Bi" <dandan.bi@intel.com>]

Reviewed-by: Dandan Bi <dandan.bi@intel.com>

Thanks,
Dandan

> -----Original Message-----
> From: Laszlo Ersek [mailto:lersek@redhat.com]
> Sent: Wednesday, September 18, 2019 3:49 AM
> To: edk2-devel-groups-io <devel@edk2.groups.io>
> Cc: Bi, Dandan <dandan.bi@intel.com>; Wu, Hao A <hao.a.wu@intel.com>;
> Wang, Jian J <jian.j.wang@intel.com>; Gao, Liming <liming.gao@intel.com>
> Subject: [PATCH 11/35] MdeModulePkg: document workaround for
> EFI_RUNTIME_EVENT_ENTRY PI spec bug
> 
> The PI spec (v1.7) correctly specifies "EFI_RUNTIME_EVENT_ENTRY.Event" in
> natural language, but the field type in the structure definition itself is wrong -
> - it should be EFI_EVENT, not (EFI_EVENT*).
> 
> This spec bug is likely unfixable for compatibility reasons, and so edk2 works
> it around already. We should clearly document the workaround.
> 
> Functionally, this patch is a no-op.
> 
> (I've also requested a non-normative (informative) clarification for the PI
> spec: <https://mantis.uefi.org/mantis/view.php?id=2017>.)
> 
> Cc: Dandan Bi <dandan.bi@intel.com>
> Cc: Hao A Wu <hao.a.wu@intel.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> ---
> 
> Notes:
>     lightly tested, as these modules are part of the ArmVirt and/or OVMF
>     platforms
> 
>  MdeModulePkg/Core/Dxe/Event/Event.c    |  8 ++++++++
>  MdeModulePkg/Core/RuntimeDxe/Runtime.c | 10 +++++++++-
>  2 files changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/MdeModulePkg/Core/Dxe/Event/Event.c
> b/MdeModulePkg/Core/Dxe/Event/Event.c
> index 21db38aaf037..c83c572c8f84 100644
> --- a/MdeModulePkg/Core/Dxe/Event/Event.c
> +++ b/MdeModulePkg/Core/Dxe/Event/Event.c
> @@ -485,6 +485,14 @@ CoreCreateEventInternal (
>      IEvent->RuntimeData.NotifyTpl      = NotifyTpl;
>      IEvent->RuntimeData.NotifyFunction = NotifyFunction;
>      IEvent->RuntimeData.NotifyContext  = (VOID *) NotifyContext;
> +    //
> +    // Work around the bug in the Platform Init specification (v1.7), reported
> +    // as Mantis#2017: "EFI_RUNTIME_EVENT_ENTRY.Event" should have
> type
> +    // EFI_EVENT, not (EFI_EVENT*). The PI spec documents the field
> correctly
> +    // as "The EFI_EVENT returned by CreateEvent()", but the type of the
> field
> +    // doesn't match the natural language description. Therefore we need an
> +    // explicit cast here.
> +    //
>      IEvent->RuntimeData.Event          = (EFI_EVENT *) IEvent;
>      InsertTailList (&gRuntime->EventHead, &IEvent->RuntimeData.Link);
>    }
> diff --git a/MdeModulePkg/Core/RuntimeDxe/Runtime.c
> b/MdeModulePkg/Core/RuntimeDxe/Runtime.c
> index c52b2b7ecf68..f7220a205d1e 100644
> --- a/MdeModulePkg/Core/RuntimeDxe/Runtime.c
> +++ b/MdeModulePkg/Core/RuntimeDxe/Runtime.c
> @@ -285,8 +285,16 @@ RuntimeDriverSetVirtualAddressMap (
>    for (Link = mRuntime.EventHead.ForwardLink; Link !=
> &mRuntime.EventHead; Link = Link->ForwardLink) {
>      RuntimeEvent = BASE_CR (Link, EFI_RUNTIME_EVENT_ENTRY, Link);
>      if ((RuntimeEvent->Type & EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE) ==
> EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE) {
> +      //
> +      // Work around the bug in the Platform Init specification (v1.7),
> +      // reported as Mantis#2017: "EFI_RUNTIME_EVENT_ENTRY.Event"
> should have
> +      // type EFI_EVENT, not (EFI_EVENT*). The PI spec documents the field
> +      // correctly as "The EFI_EVENT returned by CreateEvent()", but the type
> +      // of the field doesn't match the natural language description. Therefore
> +      // we need an explicit cast here.
> +      //
>        RuntimeEvent->NotifyFunction (
> -                      RuntimeEvent->Event,
> +                      (EFI_EVENT) RuntimeEvent->Event,
>                        RuntimeEvent->NotifyContext
>                        );
>      }
> --
> 2.19.1.3.g30247aa5d201
>