Re: [PATCH v2 04/11] MdePkg/Include: Add StandaloneMmServicesTableLib library

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

On Wed, 2 Jan 2019 at 14:14, Jagadeesh Ujja <jagadeesh.ujja@arm.com> wrote:
>
> Some of the existing DXE drivers can be refactored to execute within
> the Standalone MM execution environment as well. Allow such drivers to
> get access to the Standalone MM services tables.
>
> Add a mechanism to determine the execution mode is required.
> i.e, in MM or non-MM
>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Jagadeesh Ujja <jagadeesh.ujja@arm.com>
> ---
>  MdePkg/Include/Library/StandaloneMmServicesTableLib.h                        | 43 ++++++++++++++++++++
>  MdePkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.c   | 39 ++++++++++++++++++
>  MdePkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.inf | 36 ++++++++++++++++
>  MdePkg/MdePkg.dec                                                            |  4 ++
>  4 files changed, 122 insertions(+)
>

OK, so since the PI spec only refers to MM mode now, this library
class should be

MmServicesTableLib|Include/Library/MmServicesTableLib.h

with an implementation in MdeModulePkg that exposes the deprecated SMM
system table as the MM system table.

In StandaloneMmPkg, we can add an implementation that exposes the
standalone MM system table.

(They are binary compatible, so it is just a matter of casting one
pointer to the other)

With this in place, we can go ahead and update FaultTolerantWrite and
Variable SMM driver to switch from SmmServicesTableLib to
MmServicesTableLib. This will require existing x86 platforms to define
a new library class resolution for MmServicesTableLib, referring to
the implementation in MdeModulePkg. This is unfortunate, but it is an
unavoidable consequence of the PI spec changes.

Remaining question is what to do with InSmm() ...


> diff --git a/MdePkg/Include/Library/StandaloneMmServicesTableLib.h b/MdePkg/Include/Library/StandaloneMmServicesTableLib.h
> new file mode 100644
> index 0000000..3a27ac4
> --- /dev/null
> +++ b/MdePkg/Include/Library/StandaloneMmServicesTableLib.h
> @@ -0,0 +1,43 @@
> +/** @file
> +  Provides a service to retrieve a pointer to the Standalone MM Services Table.
> +  Provides a InMm implementation for RUNTIME DXE drivers
> +
> +Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) 2016 - 2018, ARM Limited. All rights reserved.<BR>
> +
> +This program and the accompanying materials
> +are licensed and made available under the terms and conditions of the BSD License
> +which accompanies this distribution.  The full text of the license may be found at
> +http://opensource.org/licenses/bsd-license.php
> +
> +THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +
> +**/
> +
> +#ifndef __MM_SERVICES_TABLE_LIB_H__
> +#define __MM_SERVICES_TABLE_LIB_H__
> +
> +#include <PiMm.h>
> +#include <PiDxe.h>
> +
> +extern EFI_MM_SYSTEM_TABLE         *gMmst;
> +
> +/**
> +  This function allows the caller to determine if the driver is executing in
> +  Standalone Management Mode(SMM).
> +
> +  This function returns TRUE if the driver is executing in SMM and FALSE if the
> +  driver is not executing in SMM.
> +
> +  @retval  TRUE  The driver is executing in Standalone Management Mode (SMM).
> +  @retval  FALSE The driver is not executing in Standalone Management Mode (SMM).
> +
> +**/
> +BOOLEAN
> +EFIAPI
> +InMm (
> +  VOID
> +  );
> +
> +#endif
> diff --git a/MdePkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.c b/MdePkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.c
> new file mode 100644
> index 0000000..6f37cd8
> --- /dev/null
> +++ b/MdePkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.c
> @@ -0,0 +1,39 @@
> +/** @file
> +  Standalone MM Services Table Library.
> +
> +  Copyright (c) 2018, ARM Limited. All rights reserved.<BR>
> +
> +  This program and the accompanying materials
> +  are licensed and made available under the terms and conditions of the BSD License
> +  which accompanies this distribution.  The full text of the license may be found at
> +  http://opensource.org/licenses/bsd-license.php
> +
> +  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +
> +**/
> +
> +#include <PiDxe.h>
> +#include <PiMm.h>
> +
> +EFI_MM_SYSTEM_TABLE         *gMmst = NULL;
> +
> +/**
> +  This function allows the caller to determine if the driver is executing in
> +  Standalone Management Mode(SMM).
> +
> +  This function returns TRUE if the driver is executing in SMM and FALSE if the
> +  driver is not executing in SMM.
> +
> +  @retval  TRUE  The driver is executing in Standalone Management Mode (SMM).
> +  @retval  FALSE The driver is not executing in Standalone Management Mode (SMM).
> +
> +**/
> +BOOLEAN
> +EFIAPI
> +InMm (
> +  VOID
> +  )
> +{
> +  return FALSE;
> +}
> diff --git a/MdePkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.inf b/MdePkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.inf
> new file mode 100644
> index 0000000..c94b605
> --- /dev/null
> +++ b/MdePkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.inf
> @@ -0,0 +1,36 @@
> +## @file
> +#  Provides StandaloneMmServicesTableLib.
> +#
> +#  Copyright (c) 2018, ARM Limited. All rights reserved.<BR>
> +#
> +#  This program and the accompanying materials
> +#  are licensed and made available under the terms and conditions
> +#  of the BSD License which accompanies this distribution.  The
> +#  full text of the license may be found at
> +#  http://opensource.org/licenses/bsd-license.php
> +#
> +#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> +#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 0x00010005
> +  BASE_NAME                      = StandaloneMmServicesTableLib
> +  FILE_GUID                      = 8099cfbf-9564-4c9b-9052-e66b1da88930
> +  MODULE_TYPE                    = DXE_RUNTIME_DRIVER
> +  VERSION_STRING                 = 1.0
> +  LIBRARY_CLASS                  = StandaloneMmServicesTableLib |DXE_RUNTIME_DRIVER DXE_SMM_DRIVER MM_STANDALONE
> +
> +#
> +# The following information is for reference only and not required by the build tools.
> +#
> +#  VALID_ARCHITECTURES           = IA32 X64 AARCH64
> +#
> +
> +[Sources]
> +  StandaloneMmServicesTableLib.c
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +
> diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
> index 712bd46..ec9b266 100644
> --- a/MdePkg/MdePkg.dec
> +++ b/MdePkg/MdePkg.dec
> @@ -243,6 +243,10 @@
>    ##
>    SafeIntLib|Include/Library/SafeIntLib.h
>
> +  ## @libraryclass Provides a service to retrieve a pointer to the Standalone MM Services Table.
> +  #                 Only available to MM_STANDALONE module types.
> +  MmServicesTableLib|Include/Library/StandaloneMmServicesTableLib.h
> +
>  [LibraryClasses.IA32, LibraryClasses.X64]
>    ##  @libraryclass  Abstracts both S/W SMI generation and detection.
>    ##
> --
> 2.7.4
>