Re: [PATCH] target/arm: Fix handling of cortex-m FTYPE flag in EXCRET

Re: [PATCH] target/arm: Fix handling of cortex-m FTYPE flag in EXCRET

[Peter Maydell]

On Thu, 21 Nov 2019 at 01:44, Jean-Hugues Deschênes
<Jean-Hugues.Deschenes@ossiaco.com> wrote:
>
> According to the PushStack() pseudocode in the armv7m RM,
> bit 4 of the LR should be set to NOT(CONTROL.PFCA) when
> an FPU is present. Current implementation is doing it for
> armv8, but not for armv7. This patch makes the existing
> logic applicable to both code paths.
>
> Signed-off-by: Jean-Hugues Deschenes <jean-hugues.deschenes@ossiaco.com>
> ---
>  target/arm/m_helper.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/target/arm/m_helper.c b/target/arm/m_helper.c
> index f2512e448e..595c49fe2a 100644
> --- a/target/arm/m_helper.c
> +++ b/target/arm/m_helper.c
> @@ -2173,19 +2173,18 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs)
>          if (env->v7m.secure) {
>              lr |= R_V7M_EXCRET_S_MASK;
>          }
> -        if (!(env->v7m.control[M_REG_S] & R_V7M_CONTROL_FPCA_MASK)) {
> -            lr |= R_V7M_EXCRET_FTYPE_MASK;
> -        }
>      } else {
>          lr = R_V7M_EXCRET_RES1_MASK |
>              R_V7M_EXCRET_S_MASK |
>              R_V7M_EXCRET_DCRS_MASK |
> -            R_V7M_EXCRET_FTYPE_MASK |
>              R_V7M_EXCRET_ES_MASK;
>          if (env->v7m.control[M_REG_NS] & R_V7M_CONTROL_SPSEL_MASK) {
>              lr |= R_V7M_EXCRET_SPSEL_MASK;
>          }
>      }
> +    if (!(env->v7m.control[M_REG_S] & R_V7M_CONTROL_FPCA_MASK)) {
> +        lr |= R_V7M_EXCRET_FTYPE_MASK;
> +    }
>      if (!arm_v7m_is_handler_mode(env)) {
>          lr |= R_V7M_EXCRET_MODE_MASK;
>      }
> --
> 2.17.1

Thanks, applied to my target-arm.next branch for 4.2.

-- PMM