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.