[U-Boot] [BUG] FreeBSD cannot boot with U-Boot patch efi_loader: parameter checks BLOCK_IO_PROTOCOL

Heinrich Schuchardt xypron.glpk at gmx.de
Thu Sep 19 20:57:38 UTC 2019

On 9/13/19 11:48 PM, Heinrich Schuchardt wrote:
> Hello Emmanuel,
> booting current FreeBSD fails since patch
> f59f0825e8b9fdeb8abe43ffd10c5119ca1a032f
> efi_loader: parameter checks BLOCK_IO_PROTOCOL
> The reason is that the buffer used by FreeBSD to read is not block aligned.
> The UEFI spec requires that EFI_BLOCK_IO_PROTOCOL.ReadBlocks() returns
> EFI_INVALID_PARAMETER if the buffer is not properly aligned (i.e. is not
> a multiple of EFI_BLOCK_IO_MEDIA.IoAlign)
> FreeBSD does not guarantee this alignment, e.g. efi_disk_read_blocks()
> is called with buffer 00000000995b08d0 which is not aligned to a
> multiple of 512.
> FreeBSD function efipart_readwrite writes this error message:
> efipart_readwrite: rw=1, blk=62333952 size=1 status=2
> The problem can be traced back to the FreeBSD line:
> stand/efi/libefi/efipart.c(1043) efipart_realstrategy():
> blkbuf = malloc(blkio->Media->BlockSize);
> U-Boot does not yet implement the EFI_DISK_IO_PROTOCOL which is a
> wrapper for the EFI_BLOCK_IO_PROTOCOL allowing unaligned access.
> malloc() could be replaced in FreeBSD by AllocatePages() which returns a
> 4096 byte aligned memory block.
> Best regards
> Heinrich

Commit 16ef880ce6ee ("loader.efi: efipart needs to use ioalign") was
merged into FreeBSD on Sep 17th, 2019.

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