Re: [PATCH] ARM: Drop ThumbEE support

[Hans van Kranenburg <hans@xxxxxxxxxxx>]

Hi Andrew,

On 12/3/25 6:16 PM, Andrew Cooper wrote:
> It was reported that Xen no longer builds on Debian Trixie:

The FTBFS is on Debian *unstable/sid*.

The build on Debian 13 Trixie is OK.

>   Assembler messages:
>   {standard input}:474: Error: unknown or missing system register name at 
> operand 1 -- `msr TEECR32_EL1,x0'
>   {standard input}:480: Error: unknown or missing system register name at 
> operand 1 -- `msr TEEHBR32_EL1,x0'
>   {standard input}:488: Error: unknown or missing system register name at 
> operand 2 -- `mrs x0,TEECR32_EL1'
>   {standard input}:494: Error: unknown or missing system register name at 
> operand 2 -- `mrs x0,TEEHBR32_EL1'
>   make[5]: *** [Rules.mk:249: arch/arm/domain.o] Error 1
> 
> This turns out to be an intentional change in bintuils.  ThumbEE was dropped
> from the architecture and doesn't exist in v8 (i.e. AArch64).
> 
> Xen supports v7+virt extentions so in principle we could #ifdef CONFIG_ARM_32
> to keep it working, but there was apparently no use of ThumbEE outside of demo
> code, so simply drop it.
> 
> Reported-by: Hans van Kranenburg <hans@xxxxxxxxxxx>

Thanks!

I have just applied the patch here and have now successfully built the
Debian Xen packages using Debian unstable/sid build chroot on the arm64
Debian VM that I have here on my work macbook.

Hans

> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> CC: Julien Grall <julien@xxxxxxx>
> CC: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
> CC: Bertrand Marquis <bertrand.marquis@xxxxxxx>
> CC: Michal Orzel <michal.orzel@xxxxxxx>
> CC: Jan Beulich <JBeulich@xxxxxxxx>
> CC: Hans van Kranenburg <hans@xxxxxxxxxxx>
> CC: Maximilian Engelhardt <maxi@xxxxxxxxxxxxx>
> 
> There's been no movement on this and it's urgent.  This (cross)compiles for
> me, but is the sum total of testing it's had.
> 
> Bintuils link: 
> https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=8c0024ca8f6c01fc45f081f5ef11c9a6a1c24eb0
> [...]