[ipxe-devel] [PATCH 1/1] [efi] avoid unaligned read in efi_devpath_end()

Michael Brown mcb30 at ipxe.org
Wed Mar 28 19:19:12 UTC 2018

On 28/03/18 20:11, Heinrich Schuchardt wrote:
> with the patch above I reach the iPXE prompt on a BananaPi. But when
> executing the dhcp command I see another "data abort", see below.
> I am trying to track down, in which routine this happens. The error
> occurs in monojob_wait(). Where do I find the job-code that is executed
> in monojob_wait?

I'm not particularly surprised.  The UEFI spec apparently[*] requires 
the MMU to be enabled and for unaligned accesses to be permitted.  The 
iPXE code therefore assumes that it can make unaligned accesses to 
network packet contents, and that this will just result in a slowdown 
rather than a crash.

Given the number of places at which an unaligned access could occur, I 
think you will probably need to enable the MMU.

[*] according to various people at ARM that I spoke to while creating 
the ARM port of iPXE


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