From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752723AbbFAT4y (ORCPT ); Mon, 1 Jun 2015 15:56:54 -0400 Received: from g4t3426.houston.hp.com ([15.201.208.54]:33258 "EHLO g4t3426.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753168AbbFAT4Q (ORCPT ); Mon, 1 Jun 2015 15:56:16 -0400 From: Toshi Kani To: bp@alien8.de, 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@ml01.01.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 Subject: [PATCH v12 2/10] x86, mm, pat: Change reserve_memtype() for WT Date: Mon, 1 Jun 2015 13:36:25 -0600 Message-Id: <1433187393-22688-3-git-send-email-toshi.kani@hp.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1433187393-22688-1-git-send-email-toshi.kani@hp.com> References: <1433187393-22688-1-git-send-email-toshi.kani@hp.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When a RAM range is requested to reserve_memtype(), it calls reserve_ram_pages_type() to verify the requested type. reserve_ram_pages_type() is changed to fail WT and WP requests with -EINVAL since set_page_memtype() is limited to handle three types, WB, WC and UC-. Signed-off-by: Toshi Kani Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Thomas Gleixner --- Patch 8/10 enhances set_page_memtype() to support WT. --- arch/x86/mm/pat.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 83af01a..56c8b4d 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -401,6 +401,8 @@ static int pat_pagerange_is_ram(resource_size_t start, resource_size_t end) /* * For RAM pages, we use page flags to mark the pages with appropriate type. + * The page flags are limited to three types, WB, WC and UC-. + * WT and WP requests fail with -EINVAL, and UC gets redirected to UC-. * Here we do two pass: * - Find the memtype of all the pages in the range, look for any conflicts * - In case of no conflicts, set the new memtype for pages in the range @@ -412,6 +414,13 @@ static int reserve_ram_pages_type(u64 start, u64 end, struct page *page; u64 pfn; + if ((req_type == _PAGE_CACHE_MODE_WT) || + (req_type == _PAGE_CACHE_MODE_WP)) { + if (new_type) + *new_type = _PAGE_CACHE_MODE_UC_MINUS; + return -EINVAL; + } + if (req_type == _PAGE_CACHE_MODE_UC) { /* We do not support strong UC */ WARN_ON_ONCE(1); @@ -461,6 +470,7 @@ static int free_ram_pages_type(u64 start, u64 end) * - _PAGE_CACHE_MODE_WC * - _PAGE_CACHE_MODE_UC_MINUS * - _PAGE_CACHE_MODE_UC + * - _PAGE_CACHE_MODE_WT * * If new_type is NULL, function will return an error if it cannot reserve the * region with req_type. If new_type is non-NULL, function will return