Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933663AbaGOTpk (ORCPT ); Tue, 15 Jul 2014 15:45:40 -0400 Received: from g9t1613g.houston.hp.com ([15.240.0.71]:38538 "EHLO g9t1613g.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933165AbaGOTpe (ORCPT ); Tue, 15 Jul 2014 15:45:34 -0400 From: Toshi Kani To: hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, akpm@linux-foundation.org, arnd@arndb.de, konrad.wilk@oracle.com, plagnioj@jcrosoft.com, tomi.valkeinen@ti.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, stefan.bader@canonical.com, luto@amacapital.net, airlied@gmail.com, bp@alien8.de, Toshi Kani Subject: [RFC PATCH 3/11] x86, mm, pat: Change reserve_memtype() to handle WT type Date: Tue, 15 Jul 2014 13:34:36 -0600 Message-Id: <1405452884-25688-4-git-send-email-toshi.kani@hp.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1405452884-25688-1-git-send-email-toshi.kani@hp.com> References: <1405452884-25688-1-git-send-email-toshi.kani@hp.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch changes reserve_memtype() to handle the new WT type. When (!pat_enabled && new_type), it continues to set either WB or UC- to *new_type. When pat_enabled, it can reserve a given non-RAM range for WT. At this point, it 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 | 2 ++ arch/x86/mm/pat.c | 12 +++++++++--- arch/x86/mm/pat_internal.h | 1 + 3 files changed, 12 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/cacheflush.h b/arch/x86/include/asm/cacheflush.h index 9863ee3..c80a3a1 100644 --- a/arch/x86/include/asm/cacheflush.h +++ b/arch/x86/include/asm/cacheflush.h @@ -42,6 +42,8 @@ static inline void set_page_memtype(struct page *pg, unsigned long memtype) unsigned long old_flags; unsigned long new_flags; + BUG_ON(memtype == _PAGE_CACHE_WT); + switch (memtype) { case _PAGE_CACHE_WC: memtype_flags = _PGMT_WC; diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 176d4d6..8a8be17 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -203,6 +203,8 @@ 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 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 @@ -213,6 +215,9 @@ static int reserve_ram_pages_type(u64 start, u64 end, unsigned long req_type, struct page *page; u64 pfn; + if (req_type == _PAGE_CACHE_WT) + return -EINVAL; + for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) { unsigned long type; @@ -254,6 +259,7 @@ static int free_ram_pages_type(u64 start, u64 end) * req_type typically has one of the: * - _PAGE_CACHE_WB * - _PAGE_CACHE_WC + * - _PAGE_CACHE_WT * - _PAGE_CACHE_UC_MINUS * * If new_type is NULL, function will return an error if it cannot reserve the @@ -274,10 +280,10 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type, if (!pat_enabled) { /* This is identical to page table setting without PAT */ if (new_type) { - if (req_type == _PAGE_CACHE_WC) - *new_type = _PAGE_CACHE_UC_MINUS; + if (req_type == _PAGE_CACHE_WB) + *new_type = _PAGE_CACHE_WB; else - *new_type = req_type & _PAGE_CACHE_MASK; + *new_type = _PAGE_CACHE_UC_MINUS; } return 0; } diff --git a/arch/x86/mm/pat_internal.h b/arch/x86/mm/pat_internal.h index 2593d40..7ae6b37 100644 --- a/arch/x86/mm/pat_internal.h +++ b/arch/x86/mm/pat_internal.h @@ -20,6 +20,7 @@ static inline char *cattr_name(unsigned long flags) case _PAGE_CACHE_UC_MINUS: return "uncached-minus"; case _PAGE_CACHE_WB: return "write-back"; case _PAGE_CACHE_WC: return "write-combining"; + case _PAGE_CACHE_WT: return "write-through"; default: return "broken"; } } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/