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From: Florian Weimer <fw@deneb.enyo.de>
To: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: libc-alpha@sourceware.org,  Sudakshina Das <Sudi.Das@arm.com>
Subject: Re: [PATCH 11/12] aarch64: redefine RETURN_ADDRESS to strip PAC
References: <20200430173458.GV29015@arm.com> <20200430174518.GG29015@arm.com>
Date: Mon, 11 May 2020 21:22:32 +0200
In-Reply-To: <20200430174518.GG29015@arm.com> (Szabolcs Nagy's message of
 "Thu, 30 Apr 2020 18:45:18 +0100")
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* Szabolcs Nagy:

> +/* This is needed when glibc is built with -mbranch-protection=pac-ret.  */
> +#undef RETURN_ADDRESS
> +#define RETURN_ADDRESS(n) XPAC(__builtin_return_address(n))

This looks suspicious.  Is __builtin_return_address ever useful
without the decoding?  If not, why doesn't GCC emit the PAC removal
itself?