On Tue Nov 27, 2018 at 09:38:24AM +0100, Ard Biesheuvel wrote:
> On Tue, 27 Nov 2018 at 09:36, Sughosh Ganu <[email protected]> wrote:
> >
> > hi Ard,
> >
> > On Tue Nov 27, 2018 at 09:14:52AM +0100, Ard Biesheuvel wrote:
> > > On Tue, 27 Nov 2018 at 07:20, Sughosh Ganu <[email protected]> wrote:
> > > >
> > > > From: Achin Gupta <[email protected]>
> > > >
> > > > The Standalone MM environment runs in S-EL0 in AArch64 on ARM Standard
> > > > Platforms. Privileged firmware e.g. ARM Trusted Firmware sets up its
> > > > architectural context including the initial translation tables for the
> > > > S-EL1/EL0 translation regime. The MM environment will still request ARM
> > > > TF to change the memory attributes of memory regions during
> > > > initialization.
> > > >
> > > > The Standalone MM image is a FV that encapsulates the MM foundation
> > > > and drivers. These are PE-COFF images with data and text segments.
> > > > To initialise the MM environment, Arm Trusted Firmware has to create
> > > > translation tables with sane default attributes for the memory
> > > > occupied by the FV. This library sends SVCs to ARM Trusted Firmware
> > > > to request memory permissions change for data and text segments.
> > > >
> > > > This patch adds a simple MMU library suitable for execution in S-EL0 and
> > > > requesting memory permissions change operations from Arm Trusted 
> > > > Firmware.
> > > >
> > > > Contributed-under: TianoCore Contribution Agreement 1.1
> > > > Signed-off-by: Sughosh Ganu <[email protected]>
> > > > ---
> > > >  ArmPkg/ArmPkg.dec                                                      
> > > >                                                                         
> > > >          |   1 +
> > > >  
> > > > ArmVirtPkg/Library/XenArmGenericTimerVirtCounterLib/XenArmGenericTimerVirtCounterLib.inf
> > > >  => ArmPkg/Library/StandaloneMmMmuLib/ArmMmuStandaloneMmLib.inf |  23 
> > > > +--
> > > >  ArmPkg/Include/Library/{ArmMmuLib.h => StandaloneMmMmuLib.h}           
> > > >                                                                         
> > > >          |  38 +---
> > > >  ArmPkg/Library/StandaloneMmMmuLib/Aarch64/ArmMmuStandaloneMmLib.c      
> > > >                                                                         
> > > >          | 185 ++++++++++++++++++++
> > > >  4 files changed, 203 insertions(+), 44 deletions(-)
> >
> >
> > <snip>
> >
> > > > +#endif /* __STANDALONEMM_MMU_LIB__ */
> > > > diff --git 
> > > > a/ArmPkg/Library/StandaloneMmMmuLib/Aarch64/ArmMmuStandaloneMmLib.c 
> > > > b/ArmPkg/Library/StandaloneMmMmuLib/Aarch64/ArmMmuStandaloneMmLib.c
> > > > new file mode 100644
> > > > index 000000000000..d7d87b7d5d69
> > > > --- /dev/null
> > > > +++ b/ArmPkg/Library/StandaloneMmMmuLib/Aarch64/ArmMmuStandaloneMmLib.c
> > > > @@ -0,0 +1,185 @@
> > > > +/** @file
> > > > +*  File managing the MMU for ARMv8 architecture in S-EL0
> > > > +*
> > > > +*  Copyright (c) 2017 - 2018, ARM Limited. All rights reserved.
> > > > +*
> > > > +*  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 <Uefi.h>
> > > > +#include <Chipset/AArch64.h>
> > >
> > > Why do you need this include? If you can drop it, can you also make
> > > the library generic (i.e., supporting ARM as well as AArch64) ?
> > >
> > > (apologies for not spotting this before)
> >
> > I can remove the header file if it is superfluous. But regarding your
> > comment on making this code generic for Arm as well, i guess we
> > can work on refactoring the code when/if we actually require to
> > support this on Arm. I am not sure if we are going to have a use-case
> > for StandaloneMM on Arm. Currently, we are only supporting it on
> > Aarch64 based platforms. Is that fine. Please let me know. Thanks.
> >
> 
> I'd strongly prefer this code to be generic if you are not using any
> AArch64 specific facilities.
> 
> AFAICT, we'd simply need to move the file out of the AArch64 directory
> and rename [Sources.AARCH64] to [Sources] in the .inf file if the
> header dependency is indeed superfluous.

There are a couple of places where we use something like
ARM_SVC_ID_SP_GET_MEM_ATTRIBUTES_AARCH64. Apart from this, it is
generic.

-sughosh
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