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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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        Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: Re: [PATCH v2 01/39] Documentation/x86: Add CET description
References: <20220929222936.14584-1-rick.p.edgecombe@intel.com>
        <20220929222936.14584-2-rick.p.edgecombe@intel.com>
Date:   Mon, 10 Oct 2022 14:19:00 +0200
In-Reply-To: <20220929222936.14584-2-rick.p.edgecombe@intel.com> (Rick
        Edgecombe's message of "Thu, 29 Sep 2022 15:28:58 -0700")
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* Rick Edgecombe:

> +To build a CET-enabled kernel, Binutils v2.31 and GCC v8.1 or LLVM v10.0.1
> +or later are required. To build a CET-enabled application, GLIBC v2.28 or
> +later is also required.

Uhm, I think we are using binutils 2.30 with extra fixes.  I hope that
these binaries are still valid.

More importantly, glibc needs to be configured with --enable-cet
explicitly (unless the compiler defaults to CET).  The default glibc
build with a default GCC will produce dynamically-linked executables
that disable CET (when running on later/differently configured glibc
builds).  The statically linked object files are not marked up for CET
in that case.

I think the goal is to support the new kernel interface for actually
switching on SHSTK in glibc 2.37.  But at that point, hopefully all
those existing binaries can start enjoying the STSTK benefits.

Thanks,
Florian