Re: port-evbarm/54554 (Booting via U-Boot fails due to buffer misalignment)

[Simon South <simon%simonsouth.net@localhost>]

The following reply was made to PR port-evbarm/54554; it has been noted by GNATS.

From: Simon South <simon%simonsouth.net@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: port-evbarm/54554 (Booting via U-Boot fails due to buffer
 misalignment)
Date: Wed, 18 Sep 2019 10:00:52 -0400

 On 2019-09-18 9:48 a.m., Jared McNeill wrote:
 > According to UEFI IoAlign may be 0 or 1 ("no alignment required"). Can 
 > you update the patch to take this into consideration?
 
 Certainly, but that doesn't seem to match U-Boot's interpretation of the 
 IoAlign field. Where are you reading this description? (And how would we 
 know what to align the buffer to when IoAlign is 1?)
 
 The relevant code[1] in U-Boot is
 
      /* media->io_align is a power of 2 */
      if ((uintptr_t)buffer & (this->media->io_align - 1))
          return EFI_INVALID_PARAMETER;
 
 which clearly uses IoAlign directly to check for alignment.
 
 [1] 
 https://gitlab.denx.de/u-boot/u-boot/blob/a9fa70b7b7167487affc5d919e541872c99e814b/lib/efi_loader/efi_disk.c#L124
 
 -- 
 Simon South
 simon%simonsouth.net@localhost