From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yk0-f176.google.com (mail-yk0-f176.google.com [209.85.160.176]) by kanga.kvack.org (Postfix) with ESMTP id A9E886B0037 for ; Thu, 4 Sep 2014 14:47:34 -0400 (EDT) Received: by mail-yk0-f176.google.com with SMTP id 19so6209499ykq.7 for ; Thu, 04 Sep 2014 11:47:34 -0700 (PDT) Received: from g6t1525.atlanta.hp.com (g6t1525.atlanta.hp.com. [15.193.200.68]) by mx.google.com with ESMTPS id i1si13577413yhg.148.2014.09.04.11.47.34 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Thu, 04 Sep 2014 11:47:34 -0700 (PDT) From: Toshi Kani Subject: [PATCH 2/5] x86, mm, pat: Change reserve_memtype() to handle WT Date: Thu, 4 Sep 2014 12:35:36 -0600 Message-Id: <1409855739-8985-3-git-send-email-toshi.kani@hp.com> In-Reply-To: <1409855739-8985-1-git-send-email-toshi.kani@hp.com> References: <1409855739-8985-1-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@linuxfoundation.org, arnd@arndb.de Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, jgross@suse.com, stefan.bader@canonical.com, luto@amacapital.net, konrad.wilk@oracle.com, Toshi Kani This patch changes reserve_memtype() to handle the WT cache mode. When PAT is not enabled, it continues to set UC- to *new_type for any non-WB request. When a target range is RAM, reserve_ram_pages_type() fails for WT for now. This function may not reserve a RAM range for WT since reserve_ram_pages_type() uses the page flags limited to three memory types, WB, WC and UC. Signed-off-by: Toshi Kani --- arch/x86/include/asm/cacheflush.h | 4 ++++ arch/x86/mm/pat.c | 16 +++++++++++++--- 2 files changed, 17 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/cacheflush.h b/arch/x86/include/asm/cacheflush.h index 157644b..c912680 100644 --- a/arch/x86/include/asm/cacheflush.h +++ b/arch/x86/include/asm/cacheflush.h @@ -53,6 +53,10 @@ static inline void set_page_memtype(struct page *pg, case _PAGE_CACHE_MODE_WB: memtype_flags = _PGMT_WB; break; + case _PAGE_CACHE_MODE_WT: + case _PAGE_CACHE_MODE_WP: + pr_err("set_page_memtype: unsupported cachemode %d\n", memtype); + BUG(); default: memtype_flags = _PGMT_DEFAULT; break; diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index b1891dc..87b21dd 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -271,6 +271,8 @@ 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 currently limited to three types, WB, WC and UC. Hence, + * any request to WT or WP will fail with -EINVAL. * 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 @@ -282,6 +284,13 @@ 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); @@ -331,6 +340,7 @@ 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 @@ -350,10 +360,10 @@ int reserve_memtype(u64 start, u64 end, enum page_cache_mode req_type, if (!pat_enabled) { /* This is identical to page table setting without PAT */ if (new_type) { - if (req_type == _PAGE_CACHE_MODE_WC) - *new_type = _PAGE_CACHE_MODE_UC_MINUS; + if (req_type == _PAGE_CACHE_MODE_WB) + *new_type = _PAGE_CACHE_MODE_WB; else - *new_type = req_type; + *new_type = _PAGE_CACHE_MODE_UC_MINUS; } 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