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From:   Florian Weimer <fweimer@redhat.com>
To:     "H.J. Lu" <hjl.tools@gmail.com>
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Subject: Re: [PATCH v11 25/25] x86/cet/shstk: Add arch_prctl functions for shadow stack
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Date:   Fri, 28 Aug 2020 08:23:54 +0200
In-Reply-To: <CAMe9rOrt5hz6qsNAxPgdKCOhRcKKESv-D3rxdSfraeJ-LFHM4w@mail.gmail.com>
        (H. J. Lu's message of "Thu, 27 Aug 2020 18:44:27 -0700")
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* H. J. Lu:

> Can you think of ANY issues of passing more arguments to arch_prctl?

On x32, the glibc arch_prctl system call wrapper only passes two
arguments to the kernel, and applications have no way of detecting that.
musl only passes two arguments on all architectures.  It happens to work
anyway with default compiler flags, but that's an accident.

Thanks,
Florian