Re: [PATCH v2 09/17] linux-user/aarch64: Implement PR_TAGGED_ADDR_ENABLE

[Peter Maydell]

On Fri, 5 Jun 2020 at 05:17, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> This is the prctl bit that controls whether syscalls accept tagged
> addresses.  See Documentation/arm64/tagged-address-abi.rst in the
> linux kernel.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  linux-user/aarch64/target_syscall.h |  4 ++++
>  linux-user/syscall.c                | 23 +++++++++++++++++++++++
>  2 files changed, 27 insertions(+)
>

> +        case TARGET_PR_SET_TAGGED_ADDR_CTRL:
> +            {
> +                abi_ulong valid_mask = TARGET_PR_TAGGED_ADDR_ENABLE;
> +
> +                if ((arg2 & ~valid_mask) || arg3 || arg4 || arg5) {
> +                    return -TARGET_EINVAL;
> +                }
> +                untagged_addr_mask = (arg2 & TARGET_PR_TAGGED_ADDR_ENABLE
> +                                      ? MAKE_64BIT_MASK(0, 56) : -1);
> +                return 0;
> +            }

The spec says the tagged-address control is thread-scoped, not process-wide.

thanks
-- PMM