Hi Andrew,

> On 4 Dec 2025, at 10:38, Andrew Cooper <[email protected]> wrote:
> 
> It was reported that Xen no longer builds on Debian unstable/sid.
> 
>  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 binutils.  ThumbEE was dropped
> ahead of ARM v8 (i.e. AArch64).
> 
> Xen supports ARM v7+virt extensions so in principle we could #ifdef
> CONFIG_ARM_32 to keep it working.  However, there was apparently no use of
> ThumbEE outside of demo code, so simply drop it.
> 
> On ThumbEE capable hardware, unconditionally trap ThumbEE instructions, and
> drop the context switching logic for TEE{CR,HBR}32.
> 
> Reported-by: Hans van Kranenburg <[email protected]>
> Signed-off-by: Andrew Cooper <[email protected]>

Looks good to me:

Reviewed-by: Bertrand Marquis <[email protected]>

Cheers
Bertrand


Reply via email to