Re: [PATCH v7 25/42] target/arm: Implement helper_mte_check1

[Peter Maydell]

On Wed, 3 Jun 2020 at 02:13, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Fill out the stub that was added earlier.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  target/arm/internals.h  |  47 +++++++++++++++
>  target/arm/mte_helper.c | 126 +++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 172 insertions(+), 1 deletion(-)
>
> diff --git a/target/arm/internals.h b/target/arm/internals.h
> index fb92ef6b84..8ae80f3945 100644
> --- a/target/arm/internals.h
> +++ b/target/arm/internals.h
> @@ -1318,6 +1318,9 @@ FIELD(MTEDESC, WRITE, 8, 1)
>  FIELD(MTEDESC, ESIZE, 9, 5)
>  FIELD(MTEDESC, TSIZE, 14, 10)  /* mte_checkN only */
>
> +bool mte_probe1(CPUARMState *env, uint32_t desc, uint64_t ptr, uintptr_t ra);
> +uint64_t mte_check1(CPUARMState *env, uint32_t desc, uint64_t ptr, uintptr_t 
> ra);
> +
>  static inline int allocation_tag_from_addr(uint64_t ptr)
>  {
>      return extract64(ptr, 56, 4);
> @@ -1328,4 +1331,48 @@ static inline uint64_t 
> address_with_allocation_tag(uint64_t ptr, int rtag)
>      return deposit64(ptr, 56, 4, rtag);
>  }
>
> +/* Return true if tbi bits mean that the access is checked.  */
> +static inline bool tbi_check(uint32_t desc, int bit55)
> +{
> +    return (desc >> (R_MTEDESC_TBI_SHIFT + bit55)) & 1;
> +}
> +
> +/* Return true if tcma bits mean that the access is unchecked.  */
> +static inline bool tcma_check(uint32_t desc, int bit55, int ptr_tag)

It's a bit confusing that one of these foo_check()s returns
"true for checked access" and the other one returns "true
for unchecked access"...

thanks
-- PMM