From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73E43C43603 for ; Thu, 19 Dec 2019 11:43:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 41BF524672 for ; Thu, 19 Dec 2019 11:43:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ellerman.id.au header.i=@ellerman.id.au header.b="MCXmEwVe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726713AbfLSLnW (ORCPT ); Thu, 19 Dec 2019 06:43:22 -0500 Received: from bilbo.ozlabs.org ([203.11.71.1]:56657 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726652AbfLSLnW (ORCPT ); Thu, 19 Dec 2019 06:43:22 -0500 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 47dqkr062jz9sQp; Thu, 19 Dec 2019 22:43:15 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ellerman.id.au; s=201909; t=1576755798; bh=lcmpp8435heHWbtamXbY25s9q0noKpvN6s1RHv0A4dU=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=MCXmEwVeEGSrPzejttS1VELaA0lq2R8UNCc4QCqV43s78jIlcRjRXv1S8XBvlhbxW IkoYXHNqhQIeWBcAK6QQ13jD2l+4fY8dZxbNHccQLM7IXL5pmxQI8SonUryHqe143E Z00iIdazUTC/s2Q8EHdFfNg7Ozt6zULqhv2xHWD+R9htzkF/bRwYvd73/AOrTTEEzZ RF6zQlsPZB1V6Z45dFQG3KhR0AhsMDUNphcJKr7Glfg7XsKDR/CjV++nR30kBwX+Sf rXWV3SJUWjIFPjwluKiKRajaxNNvAsba4tI/inSmk+mwbxQYOB9QU/pZrP4DMMAjkc 3czhs1rexhIeg== From: Michael Ellerman To: Steven Price , Andrew Morton , linux-mm@kvack.org Cc: Steven Price , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Dave Hansen , Ingo Molnar , James Morse , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Peter Zijlstra , Thomas Gleixner , Will Deacon , x86@kernel.org, "H. Peter Anvin" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Mark Rutland , "Liang\, Kan" , Mark Rutland Subject: Re: [PATCH v17 01/23] mm: Add generic p?d_leaf() macros In-Reply-To: <20191218162402.45610-2-steven.price@arm.com> References: <20191218162402.45610-1-steven.price@arm.com> <20191218162402.45610-2-steven.price@arm.com> Date: Thu, 19 Dec 2019 22:43:14 +1100 Message-ID: <878sn8mtgt.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Steven Price writes: > Exposing the pud/pgd levels of the page tables to walk_page_range() means > we may come across the exotic large mappings that come with large areas > of contiguous memory (such as the kernel's linear map). > > For architectures that don't provide all p?d_leaf() macros, provide > generic do nothing default that are suitable where there cannot be leaf > pages at that level. Futher patches will add implementations for > individual architectures. > > The name p?d_leaf() is chosen to minimize the confusion with existing > uses of "large" pages and "huge" pages which do not necessary mean that > the entry is a leaf (for example it may be a set of contiguous entries > that only take 1 TLB slot). For the purpose of walking the page tables > we don't need to know how it will be represented in the TLB, but we do > need to know for sure if it is a leaf of the tree. > > Signed-off-by: Steven Price > Acked-by: Mark Rutland > --- > include/asm-generic/pgtable.h | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h > index 798ea36a0549..e2e2bef07dd2 100644 > --- a/include/asm-generic/pgtable.h > +++ b/include/asm-generic/pgtable.h > @@ -1238,4 +1238,24 @@ static inline bool arch_has_pfn_modify_check(void) > #define mm_pmd_folded(mm) __is_defined(__PAGETABLE_PMD_FOLDED) > #endif > > +/* > + * p?d_leaf() - true if this entry is a final mapping to a physical address. > + * This differs from p?d_huge() by the fact that they are always available (if > + * the architecture supports large pages at the appropriate level) even > + * if CONFIG_HUGETLB_PAGE is not defined. > + * Only meaningful when called on a valid entry. > + */ > +#ifndef pgd_leaf > +#define pgd_leaf(x) 0 > +#endif > +#ifndef p4d_leaf > +#define p4d_leaf(x) 0 > +#endif > +#ifndef pud_leaf > +#define pud_leaf(x) 0 > +#endif > +#ifndef pmd_leaf > +#define pmd_leaf(x) 0 > +#endif Any reason you made these #defines rather than static inlines? cheers