From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f49.google.com (mail-wm0-f49.google.com [74.125.82.49]) by kanga.kvack.org (Postfix) with ESMTP id 3F60D6B0254 for ; Tue, 8 Dec 2015 09:18:20 -0500 (EST) Received: by wmww144 with SMTP id w144so182791212wmw.1 for ; Tue, 08 Dec 2015 06:18:19 -0800 (PST) Received: from Galois.linutronix.de (linutronix.de. [2001:470:1f0b:db:abcd:42:0:1]) by mx.google.com with ESMTPS id dc4si4562053wjc.52.2015.12.08.06.18.18 for (version=TLS1_2 cipher=AES128-SHA bits=128/128); Tue, 08 Dec 2015 06:18:19 -0800 (PST) Date: Tue, 8 Dec 2015 15:17:11 +0100 (CET) From: Thomas Gleixner Subject: Re: [PATCH 09/34] x86, pkeys: store protection in high VMA flags In-Reply-To: <20151204011437.1F3BB55E@viggo.jf.intel.com> Message-ID: References: <20151204011424.8A36E365@viggo.jf.intel.com> <20151204011437.1F3BB55E@viggo.jf.intel.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, dave.hansen@linux.intel.com On Thu, 3 Dec 2015, Dave Hansen wrote: > vma->vm_flags is an 'unsigned long', so has space for 32 flags > on 32-bit architectures. The high 32 bits are unused on 64-bit > platforms. We've steered away from using the unused high VMA > bits for things because we would have difficulty supporting it > on 32-bit. > > Protection Keys are not available in 32-bit mode, so there is > no concern about supporting this feature in 32-bit mode or on > 32-bit CPUs. > > This patch carves out 4 bits from the high half of > vma->vm_flags and allows architectures to set config option > to make them available. > > Sparse complains about these constants unless we explicitly > call them "UL". > > Signed-off-by: Dave Hansen Reviewed-by: Thomas Gleixner -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org