Re: [PATCH for-8.1] target/arm: Special case M-profile in debug_helper.c code

[Richard Henderson <richard.henderson@linaro.org>]

On 7/21/23 15:32, Peter Maydell wrote:
> A lot of the code called from helper_exception_bkpt_insn() is written
> assuming A-profile, but we will also call this helper on M-profile
> CPUs when they execute a BKPT insn.  This used to work by accident,
> but recent changes mean that we will hit an assert when some of this
> code calls down into lower level functions that end up calling
> arm_security_space_below_el3(), arm_el_is_aa64(), and other functions
> that now explicitly assert that the guest CPU is not M-profile.
> 
> Handle M-profile directly to avoid the assertions:
>   * in arm_debug_target_el(), M-profile debug exceptions always
>     go to EL1
>   * in arm_debug_exception_fsr(), M-profile always uses the short
>     format FSR (compare commit d7fe699be54b2, though in this case
>     the code in arm_v7m_cpu_do_interrupt() does not need to
>     look at the FSR value at all)
> 
> Cc:qemu-stable@nongnu.org
> Resolves:https://gitlab.com/qemu-project/qemu/-/issues/1775
> Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
> ---
> Not sure exactly when this assert() got in (probably in the
> semi-recent refactorings for realm support), but it won't hurt
> to backport the fix even if the older QEMU doesn't assert().
> ---

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~