Re: [PATCH v2 19/28] target/arm: Implement new v8.1M NOCP check for exception return

[Richard Henderson]

On 11/19/20 3:56 PM, Peter Maydell wrote:
> In v8.1M a new exception return check is added which may cause a NOCP
> UsageFault (see rule R_XLTP): before we clear s0..s15 and the FPSCR
> we must check whether access to CP10 from the Security state of the
> returning exception is disabled; if it is then we must take a fault.
> 
> (Note that for our implementation CPPWR is always RAZ/WI and so can
> never cause CP10 accesses to fail.)
> 
> The other v8.1M change to this register-clearing code is that if MVE
> is implemented VPR must also be cleared, so add a TODO comment to
> that effect.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  target/arm/m_helper.c | 22 +++++++++++++++++++++-
>  1 file changed, 21 insertions(+), 1 deletion(-)

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

r~