Re: [Qemu-devel] [PATCH v2] target-arm: Clean up DISAS_UPDATE usage in AArch32 translation code

[Peter Maydell]

On 9 November 2015 at 19:37, Sergey Fedorov <address@hidden> wrote:
> AArch32 translation code does not distinguish between DISAS_UPDATE and
> DISAS_JUMP. Thus, we cannot use any of them without first updating PC in
> CPU state. Furthermore, it is too complicated to update PC in CPU state
> before PC gets updated in disas context. So it is hardly possible to
> correctly end TB early if is is not likely to be executed before calling
> disas_*_insn(), e.g. just after calling breakpoint check helper.
>
> Modify DISAS_UPDATE and DISAS_JUMP usage in AArch32 translation and
> apply to them the same semantic as AArch64 translation does:
>  - DISAS_UPDATE: update PC in CPU state when finishing translation
>  - DISAS_JUMP:   preserve current PC value in CPU state when finishing
>                  translation
>
> This patch fixes a bug in AArch32 breakpoint handling: when
> check_breakpoints helper does not generate an exception, ending the TB
> early with DISAS_UPDATE couldn't update PC in CPU state and execution
> hangs.
>
> Signed-off-by: Sergey Fedorov <address@hidden>



Applied to target-arm.next, thanks.

-- PMM