From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752109AbbGVSHW (ORCPT ); Wed, 22 Jul 2015 14:07:22 -0400 Received: from g2t2354.austin.hp.com ([15.217.128.53]:40396 "EHLO g2t2354.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751820AbbGVSHV (ORCPT ); Wed, 22 Jul 2015 14:07:21 -0400 From: Toshi Kani To: mingo@kernel.org Cc: tglx@linutronix.de, peterz@infradead.org, bp@suse.de, jbeulich@suse.com, x86@kernel.org, linux-kernel@vger.kernel.org, Toshi Kani Subject: [PATCH] x86, pat: Add comments to cachemode translation tables Date: Wed, 22 Jul 2015 12:06:11 -0600 Message-Id: <1437588371-28223-1-git-send-email-toshi.kani@hp.com> X-Mailer: git-send-email 2.4.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add comments to the cachemode translation tables to clarify that the default values are set as minimal supported mode, which are necessary to handle WC and WT fallback to UC- when they are not enabled. Signed-off-by: Toshi Kani Cc: Jan Beulich Cc: Borislav Petkov Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Thomas Gleixner --- Ingo, please replace the patch below with this patch. https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg937806.html --- arch/x86/mm/init.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 8533b46..1d8a83d 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -30,8 +30,11 @@ /* * Tables translating between page_cache_type_t and pte encoding. * - * Minimal supported modes are defined statically, they are modified - * during bootup if more supported cache modes are available. + * The default values are defined statically as minimal supported mode; + * WC and WT fall back to UC-. pat_init() updates these values to support + * more cache modes, WC and WT, when it is safe to do so. See pat_init() + * for the details. Note, __early_ioremap() used during early boot-time + * takes pgprot_t (pte encoding) and does not use these tables. * * Index into __cachemode2pte_tbl[] is the cachemode. *