From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Martin Subject: Re: [RFC PATCH v2 4/6] arm64: signal: Allocate extra sigcontext space as needed Date: Tue, 6 Jun 2017 14:58:18 +0100 Message-ID: <20170606135815.GG30160@e103592.cambridge.arm.com> References: <1492016239-19511-1-git-send-email-Dave.Martin@arm.com> <1492016495-19689-1-git-send-email-Dave.Martin@arm.com> <1492016495-19689-4-git-send-email-Dave.Martin@arm.com> <20170512165724.GB8387@e104818-lin.cambridge.arm.com> <20170515132442.GB3559@e103592.cambridge.arm.com> <20170523113019.GB5948@e104818-lin.cambridge.arm.com> <20170526113729.GO3559@e103592.cambridge.arm.com> <20170605141744.GB9163@e104818-lin.cambridge.arm.com> <20170606113739.GF30160@e103592.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from foss.arm.com ([217.140.101.70]:46772 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751390AbdFFN6W (ORCPT ); Tue, 6 Jun 2017 09:58:22 -0400 Content-Disposition: inline In-Reply-To: <20170606113739.GF30160@e103592.cambridge.arm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Catalin Marinas Cc: linux-arch@vger.kernel.org, Will Deacon , linux-arm-kernel@lists.infradead.org On Tue, Jun 06, 2017 at 12:37:53PM +0100, Dave Martin wrote: > On Mon, Jun 05, 2017 at 03:17:44PM +0100, Catalin Marinas wrote: [...] [extra_context.size] > > I'd rather have the time size_t or __u64 to avoid implicit padding. > > Sure, it can be a u64. I wanted to avoid the suggestion that the frame > should be that large, but 32 bits already allows it to be crazy large > anyway, so I don't think making it 32-bit helps. Actually, there is still implicit padding even with u64, since the total size is 16 bytes + sizeof(extra_context.size). Since u64 is much bigger then we'd ever want, and to avoid introducing new bugs, do you object to keeping size as u32 and adding explicit padding instead? Cheers ---Dave