Re: [Qemu-devel] bug in new ubfx code

[Ard Biesheuvel]

On 13 January 2017 at 17:27, Ard Biesheuvel <address@hidden> wrote:
> Hi all,
>
> I tracked down a boot issue I was having with running the kernel under
> AArch64 system emulation to commit
>

59a71b4c5b4e target-arm: Use new deposit and extract ops


> It appears that ubfx is executing incorrectly: the following code
>
>     .global _start
> _start:
>     mov x1, #0x1124
>     ubfx x2, x1, #28, #4
>
> built with
>
> aarch64-linux-gnu-gcc -o /tmp/ubfx /tmp/ubfx.s -nostartfiles
> aarch64-linux-gnu-objcopy -O binary /tmp/ubfx.bin /tmp/ubfx
>
> and executed with
>
> qemu-system-aarch64 -M virt -cpu cortex-a53 -kernel /tmp/ubfx -s -S -nographic
>
> produces the value 0x1124000000000 in x2 (as can be observed via GDB),
> while the expected value is 0
>
> Regards,
> Ard.