Re: [Qemu-arm] [Qemu-devel] [PATCH 02/15] target/arm: Don't trap WFI/WFE for M profile

[Richard Henderson]

On 08/02/2017 09:43 AM, Peter Maydell wrote:
> M profile cores can never trap on WFI or WFE instructions. Check for
> M profile in check_wfx_trap() to ensure this.
> 
> The existing code will do the right thing for v7M cores because
> the hcr_el2 and scr_el3 registers will be all-zeroes and so we
> won't attempt to trap, but when we start setting ARM_FEATURE_V8
> for v8M cores the v8A handling of SCTLR.nTWE and .nTWI will not
> give the right results.
> 
> Signed-off-by: Peter Maydell <address@hidden>
> ---
>  target/arm/op_helper.c | 5 +++++
>  1 file changed, 5 insertions(+)

Reviewed-by: Richard Henderson <address@hidden>

While looking at this, I think there's an error in helper_wfi.  The early exit
for cpu_has_work should happen after the exception check.


r~