Re: [PATCH v2 2/2] EmbeddedPkg: Add LoadFile2 for linux initrd

["Leif Lindholm" <leif@nuviainc.com>]

Minor style comments below.

On Wed, Sep 01, 2021 at 20:28:27 +0000, Jeff Brasen wrote:
> Add support under a pcd feature for using the new interface to pass
> initrd to the linux kernel.
> 
> Signed-off-by: Jeff Brasen <jbrasen@nvidia.com>
> ---
>  EmbeddedPkg/EmbeddedPkg.dec                   |   1 +
>  .../AndroidBootImgLib/AndroidBootImgLib.inf   |   3 +
>  .../AndroidBootImgLib/AndroidBootImgLib.c     | 147 +++++++++++++++++-
>  3 files changed, 144 insertions(+), 7 deletions(-)
> 
> diff --git a/EmbeddedPkg/EmbeddedPkg.dec b/EmbeddedPkg/EmbeddedPkg.dec
> index c2068ce5a8ce..7638aaaadeb8 100644
> --- a/EmbeddedPkg/EmbeddedPkg.dec
> +++ b/EmbeddedPkg/EmbeddedPkg.dec
> @@ -86,6 +86,7 @@ [Ppis]
>  [PcdsFeatureFlag.common]
>    gEmbeddedTokenSpaceGuid.PcdPrePiProduceMemoryTypeInformationHob|FALSE|BOOLEAN|0x0000001b
>    gEmbeddedTokenSpaceGuid.PcdGdbSerial|FALSE|BOOLEAN|0x00000053
> +  gEmbeddedTokenSpaceGuid.PcdAndroidBootLoadFile2|FALSE|BOOLEAN|0x0000005b
>  
>  [PcdsFixedAtBuild.common]
>    gEmbeddedTokenSpaceGuid.PcdPrePiStackBase|0|UINT32|0x0000000b
> diff --git a/EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.inf b/EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.inf
> index bfed4ba9dcd4..39d8abe72cd1 100644
> --- a/EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.inf
> +++ b/EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.inf
> @@ -42,3 +42,6 @@ [Protocols]
>  
>  [Guids]
>    gFdtTableGuid
> +
> +[FeaturePcd]
> +  gEmbeddedTokenSpaceGuid.PcdAndroidBootLoadFile2
> diff --git a/EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.c b/EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.c
> index 3c617649f735..635965690dc0 100644
> --- a/EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.c
> +++ b/EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.c
> @@ -10,11 +10,15 @@
>  #include <libfdt.h>
>  #include <Library/AndroidBootImgLib.h>
>  #include <Library/PrintLib.h>
> +#include <Library/DevicePathLib.h>

Move that inserted line up one to maintain alphabetical sorting.

>  #include <Library/UefiBootServicesTableLib.h>
>  #include <Library/UefiLib.h>
>  
>  #include <Protocol/AndroidBootImg.h>
>  #include <Protocol/LoadedImage.h>
> +#include <Protocol/LoadFile2.h>
> +
> +#include <Guid/LinuxEfiInitrdMedia.h>
>  
>  #include <libfdt.h>

Glad to see we're *really* including libfdt.h (also included above and
completely unrelated to this patch).

> @@ -25,7 +29,14 @@ typedef struct {
>    EFI_DEVICE_PATH_PROTOCOL                End;
>  } MEMORY_DEVICE_PATH;
>  
> +typedef struct {
> +  VENDOR_DEVICE_PATH                      VenMediaNode;

VendorMediaNode

> +  EFI_DEVICE_PATH_PROTOCOL                EndNode;
> +} RAMDISK_DEVICE_PATH;
> +
>  STATIC ANDROID_BOOTIMG_PROTOCOL                 *mAndroidBootImg;
> +STATIC VOID                                     *mRamdiskData = NULL;
> +STATIC UINTN                                    mRamdiskSize = 0;
>  
>  STATIC CONST MEMORY_DEVICE_PATH mMemoryDevicePathTemplate =
>  {
> @@ -48,6 +59,99 @@ STATIC CONST MEMORY_DEVICE_PATH mMemoryDevicePathTemplate =
>    } // End
>  };
>  
> +STATIC CONST RAMDISK_DEVICE_PATH mRamdiskDevicePath =
> +{
> +  {
> +    {
> +      MEDIA_DEVICE_PATH,
> +      MEDIA_VENDOR_DP,
> +      { sizeof (VENDOR_DEVICE_PATH), 0 }
> +    },
> +    LINUX_EFI_INITRD_MEDIA_GUID
> +  },
> +  {
> +    END_DEVICE_PATH_TYPE,
> +    END_ENTIRE_DEVICE_PATH_SUBTYPE,
> +    { sizeof (EFI_DEVICE_PATH_PROTOCOL), 0 }
> +  }
> +};
> +
> +/**
> +  Causes the driver to load a specified file.
> +
> +  @param  This       Protocol instance pointer.
> +  @param  FilePath   The device specific path of the file to load.
> +  @param  BootPolicy Should always be FALSE.
> +  @param  BufferSize On input the size of Buffer in bytes. On output with a return
> +                     code of EFI_SUCCESS, the amount of data transferred to
> +                     Buffer. On output with a return code of EFI_BUFFER_TOO_SMALL,
> +                     the size of Buffer required to retrieve the requested file.
> +  @param  Buffer     The memory buffer to transfer the file to. IF Buffer is NULL,
> +                     then no the size of the requested file is returned in
> +                     BufferSize.
> +
> +  @retval EFI_SUCCESS           The file was loaded.
> +  @retval EFI_UNSUPPORTED       BootPolicy is TRUE.
> +  @retval EFI_INVALID_PARAMETER FilePath is not a valid device path, or
> +                                BufferSize is NULL.
> +  @retval EFI_NO_MEDIA          No medium was present to load the file.
> +  @retval EFI_DEVICE_ERROR      The file was not loaded due to a device error.
> +  @retval EFI_NO_RESPONSE       The remote system did not respond.
> +  @retval EFI_NOT_FOUND         The file was not found
> +  @retval EFI_ABORTED           The file load process was manually canceled.
> +  @retval EFI_BUFFER_TOO_SMALL  The BufferSize is too small to read the current
> +                                directory entry. BufferSize has been updated with
> +                                the size needed to complete the request.
> +
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +AndroidBootImgLoadFile2 (
> +  IN EFI_LOAD_FILE2_PROTOCOL    *This,
> +  IN EFI_DEVICE_PATH_PROTOCOL   *FilePath,
> +  IN BOOLEAN                    BootPolicy,
> +  IN OUT UINTN                  *BufferSize,
> +  IN VOID                       *Buffer OPTIONAL
> +  )
> +
> +{
> +  // Verify if the valid parameters
> +  if (This == NULL ||
> +      BufferSize == NULL ||
> +      FilePath == NULL ||
> +      !IsDevicePathValid (FilePath, 0)) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (BootPolicy) {
> +    return EFI_UNSUPPORTED;
> +  }
> +
> +  // Check if the given buffer size is big enough
> +  // EFI_BUFFER_TOO_SMALL to allow caller to allocate a bigger buffer
> +  if (mRamdiskSize == 0) {
> +    return EFI_NOT_FOUND;
> +  }
> +  if (Buffer == NULL || *BufferSize < mRamdiskSize) {
> +    *BufferSize = mRamdiskSize;
> +    return EFI_BUFFER_TOO_SMALL;
> +  }
> +
> +  // Copy InitRd
> +  CopyMem (Buffer, mRamdiskData, mRamdiskSize);
> +  *BufferSize = mRamdiskSize;
> +
> +  return EFI_SUCCESS;
> +}
> +
> +///
> +/// Load File Protocol instance
> +///
> +STATIC EFI_LOAD_FILE2_PROTOCOL  mAndroidBootImgLoadFile2 = {
> +  AndroidBootImgLoadFile2
> +};
> +
>  EFI_STATUS
>  AndroidBootImgGetImgSize (
>    IN  VOID    *BootImg,
> @@ -383,6 +487,7 @@ AndroidBootImgBoot (
>    VOID                               *RamdiskData;
>    UINTN                               RamdiskSize;
>    IN  VOID                           *FdtBase;
> +  EFI_HANDLE                          RamDiskLoadFileHandle;
>  
>    NewKernelArg = NULL;
>    ImageHandle = NULL;
> @@ -423,14 +528,29 @@ AndroidBootImgBoot (
>      goto Exit;
>    }
>  
> -  Status = AndroidBootImgLocateFdt (Buffer, &FdtBase);
> -  if (EFI_ERROR (Status)) {
> -    goto Exit;
> -  }
> +  if (FeaturePcdGet (PcdAndroidBootLoadFile2)) {
> +    RamDiskLoadFileHandle = NULL;
> +    mRamdiskData = RamdiskData;
> +    mRamdiskSize = RamdiskSize;
> +    Status = gBS->InstallMultipleProtocolInterfaces (&RamDiskLoadFileHandle,
> +                                                     &gEfiLoadFile2ProtocolGuid,
> +                                                     &mAndroidBootImgLoadFile2,
> +                                                     &gEfiDevicePathProtocolGuid,
> +                                                     &mRamdiskDevicePath,
> +                                                     NULL);
> +    if (EFI_ERROR (Status)) {
> +      goto Exit;
> +    }
> +  } else {
> +    Status = AndroidBootImgLocateFdt (Buffer, &FdtBase);
> +    if (EFI_ERROR (Status)) {
> +      goto Exit;
> +    }
>  
> -  Status = AndroidBootImgUpdateFdt (Buffer, FdtBase, RamdiskData, RamdiskSize);
> -  if (EFI_ERROR (Status)) {
> -    goto Exit;
> +    Status = AndroidBootImgUpdateFdt (Buffer, FdtBase, RamdiskData, RamdiskSize);
> +    if (EFI_ERROR (Status)) {
> +      goto Exit;
> +    }

It looks to me like this changes the functionality so that if
PcdAndroidBootLoadFile2 is set, we now don't locate/update an FDT,
which was not clear to me from the cover letter and commit message.

This may well be intentional and correct, but since this function was
already a bit messy, I'd kind of prefer shunting some of this off into
helper functions now we're adding to the complexity.

/
    Leif

>    }
>  
>    KernelDevicePath = mMemoryDevicePathTemplate;
> @@ -474,5 +594,18 @@ AndroidBootImgBoot (
>        NewKernelArg = NULL;
>      }
>    }
> +  if (FeaturePcdGet (PcdAndroidBootLoadFile2)) {
> +    mRamdiskData = NULL;
> +    mRamdiskSize = 0;
> +    if (RamDiskLoadFileHandle != NULL) {
> +      gBS->UninstallMultipleProtocolInterfaces (RamDiskLoadFileHandle,
> +                                                &gEfiLoadFile2ProtocolGuid,
> +                                                &mAndroidBootImgLoadFile2,
> +                                                &gEfiDevicePathProtocolGuid,
> +                                                &mRamdiskDevicePath,
> +                                                NULL);
> +      RamDiskLoadFileHandle = NULL;
> +    }
> +  }
>
>    return Status;
>  }
> -- 
> 2.17.1
>