Re: [edk2-devel] [PATCH v1 10/11] ArmVirtPkg: Link NorFlashDxe with BaseMemoryLibMmio

["Laszlo Ersek" <lersek@redhat.com>]

On 05/14/20 10:40, Sami Mujawar wrote:
> NorFlashDxe must use aligned MMIO accesses to
> read data from flash as this is device memory.
> 
> The AlignedCopyMem() in NorFlashDxe was used to
> copy the flash data which prevented unaligned
> access to device memory. However, the compiler
> could optimize the code to generate pre/post
> indexed or LDP operations. This is a problem
> for guest/virtual firmware as the hypervisor
> code cannot get the syndrome information for
> the trapped accesses.
> 
> To address the such issues, BaseMemoryLibMmio
> library has been introduced to perform aligned
> MMIO accesses.
> 
> The NorFlashDxe has been updated to use
> CopyMem() instead of using AlignedCopyMem()
> and therefore the NorFlashDxe must be linked
> with BaseMemoryLibMmio.
> 
> This patch updates the workspace files to link
> NorFlashDxe with BaseMemoryLibMmio for the
> following platforms:
>   - Arm Qemu
>   - Arm Qemu Kernel
> 
> Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
> ---
>  ArmVirtPkg/ArmVirtQemu.dsc       | 8 ++++++--
>  ArmVirtPkg/ArmVirtQemuKernel.dsc | 8 ++++++--
>  2 files changed, 12 insertions(+), 4 deletions(-)

Based on Ard's comment under "MdePkg: Base Memory Lib instance using
MMIO" ("I don't think we need this library"), this patch would be
unnecessary too.

(This applies to the
"BaseMemoryLib|MdePkg/Library/BaseMemoryLibMmio/BaseMemoryLibMmio.inf"
resolutions in the previous patch as well, apparently.)

Thanks
Laszlo

> 
> diff --git a/ArmVirtPkg/ArmVirtQemu.dsc b/ArmVirtPkg/ArmVirtQemu.dsc
> index 3f649c91d8d6a2e3f3e62f35aa40906e048a15c4..82b7d54c2031fed60dccff38353d3ec19cfdefd0 100644
> --- a/ArmVirtPkg/ArmVirtQemu.dsc
> +++ b/ArmVirtPkg/ArmVirtQemu.dsc
> @@ -1,5 +1,5 @@
>  #
> -#  Copyright (c) 2011-2015, ARM Limited. All rights reserved.
> +#  Copyright (c) 2011-2020, ARM Limited. All rights reserved.
>  #  Copyright (c) 2014, Linaro Limited. All rights reserved.
>  #  Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.
>  #
> @@ -384,7 +384,11 @@ [Components.common]
>      <LibraryClasses>
>        NULL|ArmVirtPkg/Library/ArmVirtTimerFdtClientLib/ArmVirtTimerFdtClientLib.inf
>    }
> -  ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashDxe.inf
> +  ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashDxe.inf {
> +    <LibraryClasses>
> +      BaseMemoryLib|MdePkg/Library/BaseMemoryLibMmio/BaseMemoryLibMmio.inf
> +  }
> +
>    MdeModulePkg/Universal/WatchdogTimerDxe/WatchdogTimer.inf
>  
>    #
> diff --git a/ArmVirtPkg/ArmVirtQemuKernel.dsc b/ArmVirtPkg/ArmVirtQemuKernel.dsc
> index 2a6fd6bc06be1cc20d8c6f2bf00d88d593061edf..6cceb61e493c8c84f6564b120b0864ff817c3f31 100644
> --- a/ArmVirtPkg/ArmVirtQemuKernel.dsc
> +++ b/ArmVirtPkg/ArmVirtQemuKernel.dsc
> @@ -1,5 +1,5 @@
>  #
> -#  Copyright (c) 2011-2015, ARM Limited. All rights reserved.
> +#  Copyright (c) 2011-2020, ARM Limited. All rights reserved.
>  #  Copyright (c) 2014, Linaro Limited. All rights reserved.
>  #  Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.
>  #
> @@ -323,7 +323,11 @@ [Components.common]
>      <LibraryClasses>
>        NULL|ArmVirtPkg/Library/ArmVirtTimerFdtClientLib/ArmVirtTimerFdtClientLib.inf
>    }
> -  ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashDxe.inf
> +  ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashDxe.inf {
> +    <LibraryClasses>
> +      BaseMemoryLib|MdePkg/Library/BaseMemoryLibMmio/BaseMemoryLibMmio.inf
> +  }
> +
>    MdeModulePkg/Universal/WatchdogTimerDxe/WatchdogTimer.inf
>  
>    #
>