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From:   Florian Weimer <fweimer@redhat.com>
To:     Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc:     x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
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Subject: Re: [PATCH v2 23/39] x86: Introduce userspace API for CET enabling
References: <20220929222936.14584-1-rick.p.edgecombe@intel.com>
        <20220929222936.14584-24-rick.p.edgecombe@intel.com>
Date:   Mon, 10 Oct 2022 12:56:22 +0200
In-Reply-To: <20220929222936.14584-24-rick.p.edgecombe@intel.com> (Rick
        Edgecombe's message of "Thu, 29 Sep 2022 15:29:20 -0700")
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* Rick Edgecombe:

> +	/* Only support enabling/disabling one feature at a time. */
> +	if (hweight_long(features) > 1)
> +		return -EINVAL;

This means we'll soon need three extra system calls for x86-64 process
start: SHSTK, IBT, and switching off vsyscall emulation.  (The latter
does not need any special CPU support.)

Maybe we can do something else instead to make the strace output a
little bit cleaner?

Thanks,
Florian