From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754141AbbFDQzo (ORCPT ); Thu, 4 Jun 2015 12:55:44 -0400 Received: from mail.skyhub.de ([78.46.96.112]:51673 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753521AbbFDQzf (ORCPT ); Thu, 4 Jun 2015 12:55:35 -0400 From: Borislav Petkov To: Ingo Molnar Cc: LKML Subject: [PATCH 06/20] x86/mm: Teach is_new_memtype_allowed() about Write-Through type Date: Thu, 4 Jun 2015 18:55:14 +0200 Message-Id: <1433436928-31903-7-git-send-email-bp@alien8.de> X-Mailer: git-send-email 2.3.5 In-Reply-To: <1433436928-31903-1-git-send-email-bp@alien8.de> References: <1433436928-31903-1-git-send-email-bp@alien8.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Toshi Kani __ioremap_caller() calls reserve_memtype() and the passed down @new_pcm contains the actual page cache type it reserved in the success case. is_new_memtype_allowed() verifies if converting to the new page cache type is allowed when @pcm (the requested type) is different from @new_pcm. When WT is requested, the caller expects that writes are ordered and uncached. Therefore, enhance 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 Reviewed-by: Thomas Gleixner Cc: Andrew Morton Cc: Andy Lutomirski Cc: arnd@arndb.de Cc: Elliott@hp.com Cc: hch@lst.de Cc: hmh@hmh.eng.br Cc: H. Peter Anvin Cc: Ingo Molnar Cc: jgross@suse.com Cc: konrad.wilk@oracle.com Cc: linux-mm Cc: linux-nvdimm@lists.01.org Cc: Luis R. Rodriguez Cc: stefan.bader@canonical.com Cc: x86-ml Cc: yigal@plexistor.com Link: http://lkml.kernel.org/r/1433187393-22688-4-git-send-email-toshi.kani@hp.com Signed-off-by: Borislav Petkov --- 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 fe57e7a98839..2562e303405b 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; } -- 2.3.5