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Date:   Sun, 6 Feb 2022 22:49:40 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc:     linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Boqun Feng <boqun.feng@gmail.com>,
        "H . Peter Anvin" <hpa@zytor.com>, Paul Turner <pjt@google.com>,
        linux-api@vger.kernel.org,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Florian Weimer <fw@deneb.enyo.de>, David.Laight@aculab.com,
        carlos@redhat.com, Peter Oskolkov <posk@posk.io>,
        libc-coord@lists.openwall.com
Subject: Re: [RFC PATCH 1/3] rseq: Introduce feature size and alignment ELF
 auxiliary vector entries
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References: <20220203193853.21511-1-mathieu.desnoyers@efficios.com>
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On Thu, Feb 03, 2022 at 02:38:51PM -0500, Mathieu Desnoyers wrote:

> @@ -286,6 +287,10 @@ create_elf_tables(struct linux_binprm *bprm, const struct elfhdr *exec,
>  	if (bprm->have_execfd) {
>  		NEW_AUX_ENT(AT_EXECFD, bprm->execfd);
>  	}
> +#ifdef CONFIG_RSEQ
> +	NEW_AUX_ENT(AT_RSEQ_FEATURE_SIZE, offsetof(struct rseq, end));

I've gotta ask, what's up with offsetof(, end) vs sizeof() ?

> +	NEW_AUX_ENT(AT_RSEQ_ALIGN, __alignof__(struct rseq));
> +#endif