From: Tom Rini <trini@konsulko.com>
Date: Fri, 10 Nov 2023 16:55:28 +0000 (-0500)
Subject: Merge branch '2023-11-10-improve-semihosting-armv6' into next
X-Git-Url: http://git.dujemihanovic.xyz/img/sics.gif?a=commitdiff_plain;h=3b6db6901ff5babbb9d21f0fca750996e29d85e0;p=u-boot.git

Merge branch '2023-11-10-improve-semihosting-armv6' into next

To quote the author:
This series has a few fixes for semihosting on ARMv6 and older CPUs. The
first two patches address problems regarding the stack pointer and link
register. U-Boot runs in supervisor mode, so taking a software interrupt
will clobber sp/lr. I think we really should run in system mode, since
it has separate sp/lr registers. To quote ARM DDI 0100I:

> The remaining mode is System mode, which is not entered by any
> exception and has exactly the same registers available as User mode.
> However, it is a privileged mode and is therefore not subject to the
> User mode restrictions. It is intended for use by operating system
> tasks that need access to system resources, but wish to avoid using
> the additional registers associated with the exception modes. Avoiding
> such use ensures that the task state is not corrupted by the
> occurrence of any exception.

However, the processor mode has been supervisor for such a long time
(since relocation got introduced) that I would rather not touch it.
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3b6db6901ff5babbb9d21f0fca750996e29d85e0