Re: [PATCH v2 02/12] Revert "ArmVirtPkg/FdtClientDxe: install DT configuration table at ReadyToBoot"

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 17 March 2017 at 20:47, Laszlo Ersek <lersek@redhat.com> wrote:
> This reverts commit 18f6d4df9ece8b91b86511bcdd1cf7da478c3627.
>
> We realized that DXE drivers that are independent of AcpiPlatformDxe (that
> is, independent of QEMU's ACPI generation), such as RamDiskDxe and
> BootGraphicsResourceTableDxe, may produce and/or manipulate ACPI tables,
> at driver dispatch or even at Ready To Boot.
>
> This makes it unsafe for us to check for ACPI presence in the UEFI system
> config table in a Ready To Boot callback, in order to decide about
> exposing the DT.
>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Leif Lindholm <leif.lindholm@linaro.org>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>


> ---
>  ArmVirtPkg/FdtClientDxe/FdtClientDxe.inf |  1 -
>  ArmVirtPkg/FdtClientDxe/FdtClientDxe.c   | 49 ++++----------------
>  2 files changed, 9 insertions(+), 41 deletions(-)
>
> diff --git a/ArmVirtPkg/FdtClientDxe/FdtClientDxe.inf b/ArmVirtPkg/FdtClientDxe/FdtClientDxe.inf
> index 00017727c32c..3a0cd37040eb 100644
> --- a/ArmVirtPkg/FdtClientDxe/FdtClientDxe.inf
> +++ b/ArmVirtPkg/FdtClientDxe/FdtClientDxe.inf
> @@ -42,7 +42,6 @@ [Protocols]
>    gFdtClientProtocolGuid                  ## PRODUCES
>
>  [Guids]
> -  gEfiEventReadyToBootGuid
>    gFdtHobGuid
>    gFdtTableGuid
>
> diff --git a/ArmVirtPkg/FdtClientDxe/FdtClientDxe.c b/ArmVirtPkg/FdtClientDxe/FdtClientDxe.c
> index 4cf79f70cb2a..547a29fce62c 100644
> --- a/ArmVirtPkg/FdtClientDxe/FdtClientDxe.c
> +++ b/ArmVirtPkg/FdtClientDxe/FdtClientDxe.c
> @@ -20,7 +20,6 @@
>  #include <Library/HobLib.h>
>  #include <libfdt.h>
>
> -#include <Guid/EventGroup.h>
>  #include <Guid/Fdt.h>
>  #include <Guid/FdtHob.h>
>
> @@ -307,30 +306,6 @@ STATIC FDT_CLIENT_PROTOCOL mFdtClientProtocol = {
>    GetOrInsertChosenNode,
>  };
>
> -STATIC
> -VOID
> -EFIAPI
> -OnReadyToBoot (
> -  EFI_EVENT       Event,
> -  VOID            *Context
> -  )
> -{
> -  EFI_STATUS      Status;
> -
> -  if (!FeaturePcdGet (PcdPureAcpiBoot)) {
> -    //
> -    // Only install the FDT as a configuration table if we want to leave it up
> -    // to the OS to decide whether it prefers ACPI over DT.
> -    //
> -    Status = gBS->InstallConfigurationTable (&gFdtTableGuid, mDeviceTreeBase);
> -    ASSERT_EFI_ERROR (Status);
> -  }
> -
> -  gBS->CloseEvent (Event);
> -}
> -
> -STATIC EFI_EVENT         mReadyToBootEvent;
> -
>  EFI_STATUS
>  EFIAPI
>  InitializeFdtClientDxe (
> @@ -358,21 +333,15 @@ InitializeFdtClientDxe (
>
>    DEBUG ((EFI_D_INFO, "%a: DTB @ 0x%p\n", __FUNCTION__, mDeviceTreeBase));
>
> -  Status = gBS->InstallProtocolInterface (&ImageHandle, &gFdtClientProtocolGuid,
> -                  EFI_NATIVE_INTERFACE, &mFdtClientProtocol);
> -  if (EFI_ERROR (Status)) {
> -    return Status;
> +  if (!FeaturePcdGet (PcdPureAcpiBoot)) {
> +    //
> +    // Only install the FDT as a configuration table if we want to leave it up
> +    // to the OS to decide whether it prefers ACPI over DT.
> +    //
> +    Status = gBS->InstallConfigurationTable (&gFdtTableGuid, DeviceTreeBase);
> +    ASSERT_EFI_ERROR (Status);
>    }
>
> -  Status = gBS->CreateEventEx (
> -                  EVT_NOTIFY_SIGNAL,
> -                  TPL_CALLBACK,
> -                  OnReadyToBoot,
> -                  NULL,
> -                  &gEfiEventReadyToBootGuid,
> -                  &mReadyToBootEvent
> -                  );
> -  ASSERT_EFI_ERROR (Status);
> -
> -  return EFI_SUCCESS;
> +  return gBS->InstallProtocolInterface (&ImageHandle, &gFdtClientProtocolGuid,
> +                EFI_NATIVE_INTERFACE, &mFdtClientProtocol);
>  }
> --
> 2.9.3
>
>