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Mon, 29 Mar 2021 08:53:25 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8C08060295; Mon, 29 Mar 2021 08:53:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1617007994; bh=2R20niaf5bxdG4YIW+24bkjIIoCGKid5/1LcMREuM0M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZlPm7DUHNBMghdVBq9a9uXvksVh1X9mGWntnIPBFLCE5/pjsWxY0PXrcG++8hj82O tA40+g332vg+1yKpPBMSPnlF4C6iLea4AHYoPwamUy8DTTtLnS8zgx2Cd0U9UVg9+X Uvtbdycbeucb3AFmChOOfabIZT2CCEQE2jXiy7ndU87YfiumB1LKo6h93AER8SpFeT hWXnhhqjMlRncZb9jgDwUL+vSZQF7sNFqrAnPjWKIacPkWo+lPvd7kLLYsazcZ6vW2 wt8WuDm64dpvop+us/wX01vXRZMgBPx9xjgvqKOCvjaNvppIC+izXiYRp1CS87JEYM qpYNHUgms83zQ== Date: Mon, 29 Mar 2021 09:53:10 +0100 From: Will Deacon To: Catalin Marinas Cc: Vladimir Murzin , linux-arm-kernel@lists.infradead.org, keescook@chromium.org, dave.martin@arm.com Subject: Re: [PATCH v4 2/2] arm64: Introduce HWCAPS2_EXECONLY Message-ID: <20210329085309.GB2965@willie-the-truck> References: <20210312173811.58284-1-vladimir.murzin@arm.com> <20210312173811.58284-3-vladimir.murzin@arm.com> <20210325190000.GC15860@willie-the-truck> <20210326093553.GA5126@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210326093553.GA5126@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210329_095321_176504_38DFFBA7 X-CRM114-Status: GOOD ( 15.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Mar 26, 2021 at 09:35:53AM +0000, Catalin Marinas wrote: > On Thu, Mar 25, 2021 at 07:00:00PM +0000, Will Deacon wrote: > > On Fri, Mar 12, 2021 at 05:38:11PM +0000, Vladimir Murzin wrote: > > > With EPAN supported it might be handy to user know that PROT_EXEC > > > gives execute-only permission, so advertise it via HWCAPS2_EXECONLY > > > > > > Cc: Kees Cook > > > Cc: Catalin Marinas > > > Signed-off-by: Vladimir Murzin > > > --- > > > arch/arm64/include/asm/hwcap.h | 1 + > > > arch/arm64/include/asm/sysreg.h | 1 + > > > arch/arm64/include/uapi/asm/hwcap.h | 1 + > > > arch/arm64/kernel/cpufeature.c | 3 +++ > > > arch/arm64/kernel/cpuinfo.c | 1 + > > > 5 files changed, 7 insertions(+) > > > > I still don't see the need for this patch. Can we avoid merging it until > > somebody has a use for it, please? > > It's more about telling user-space that the feature is present though we > didn't do this last time we had exec-only permissions either. I was > hoping we can do better this time. OTOH, probably no-one will check for > this HWCAP anyway, so let's wait until someone asks for it. Yes, that's what I mean by "somebody has a use for it" -- I don't understand what userspace would do with this and it's certainly not using it now. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel