From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f175.google.com (mail-ob0-f175.google.com [209.85.214.175]) by kanga.kvack.org (Postfix) with ESMTP id 6B2706B0073 for ; Wed, 13 May 2015 17:25:26 -0400 (EDT) Received: by obbkp3 with SMTP id kp3so39747597obb.3 for ; Wed, 13 May 2015 14:25:26 -0700 (PDT) Received: from g4t3425.houston.hp.com (g4t3425.houston.hp.com. [15.201.208.53]) by mx.google.com with ESMTPS id vt3si11333707oeb.27.2015.05.13.14.25.25 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 13 May 2015 14:25:25 -0700 (PDT) From: Toshi Kani Subject: [PATCH v9 3/10] x86, asm: Change is_new_memtype_allowed() for WT Date: Wed, 13 May 2015 15:05:44 -0600 Message-Id: <1431551151-19124-4-git-send-email-toshi.kani@hp.com> In-Reply-To: <1431551151-19124-1-git-send-email-toshi.kani@hp.com> References: <1431551151-19124-1-git-send-email-toshi.kani@hp.com> Sender: owner-linux-mm@kvack.org List-ID: To: hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, akpm@linux-foundation.org, arnd@arndb.de Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-nvdimm@lists.01.org, jgross@suse.com, stefan.bader@canonical.com, luto@amacapital.net, hmh@hmh.eng.br, yigal@plexistor.com, konrad.wilk@oracle.com, Elliott@hp.com, mcgrof@suse.com, hch@lst.de, Toshi Kani __ioremap_caller() calls reserve_memtype() to set new_pcm (existing map type if any), and then calls is_new_memtype_allowed() to verify if converting to new_pcm is allowed when pcm (request type) is different from new_pcm. When WT is requested, the caller expects that writes are ordered and uncached. Therefore, this patch changes is_new_memtype_allowed() to disallow the following cases. - If the request is WT, mapping type cannot be WB - If the request is WT, mapping type cannot be WC Signed-off-by: Toshi Kani --- arch/x86/include/asm/pgtable.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index fe57e7a..2562e30 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -398,11 +398,17 @@ static inline int is_new_memtype_allowed(u64 paddr, unsigned long size, * requested memtype: * - request is uncached, return cannot be write-back * - request is write-combine, return cannot be write-back + * - request is write-through, return cannot be write-back + * - request is write-through, return cannot be write-combine */ if ((pcm == _PAGE_CACHE_MODE_UC_MINUS && new_pcm == _PAGE_CACHE_MODE_WB) || (pcm == _PAGE_CACHE_MODE_WC && - new_pcm == _PAGE_CACHE_MODE_WB)) { + new_pcm == _PAGE_CACHE_MODE_WB) || + (pcm == _PAGE_CACHE_MODE_WT && + new_pcm == _PAGE_CACHE_MODE_WB) || + (pcm == _PAGE_CACHE_MODE_WT && + new_pcm == _PAGE_CACHE_MODE_WC)) { return 0; } -- 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