From patchwork Tue Dec 6 14:47:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13065891 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 057BCC63707 for ; Tue, 6 Dec 2022 14:52:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235289AbiLFOwJ (ORCPT ); Tue, 6 Dec 2022 09:52:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47760 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235296AbiLFOvc (ORCPT ); Tue, 6 Dec 2022 09:51:32 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 91CD22E9F3 for ; Tue, 6 Dec 2022 06:49:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670338141; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XBg+RrASZLSOgjQZ+h9w7ax0WTHgQALeSHGQDl5XWVQ=; b=gW3ZK+q6AZ25skuPqFCusRXuUN8j+exl7BjJQjki4l8ciox0suJqNe9EcPoIORvXFt0Fpf aNPsnOlp+6Reyq54L77ASG0uQb52947V/cVG2IynWZ8PQ/5MnXHBbH+23w+Ncih7UZRjNG b5BjlC5VOuprmSL9yV0xxTvqvQ8OVBc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-154-Ojd-27knM6CkAPy6DTEeyw-1; Tue, 06 Dec 2022 09:48:58 -0500 X-MC-Unique: Ojd-27knM6CkAPy6DTEeyw-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id BD19985A59D; Tue, 6 Dec 2022 14:48:55 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9BCB3492B04; Tue, 6 Dec 2022 14:48:49 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: Andrew Morton , Hugh Dickins , John Hubbard , Jason Gunthorpe , Mike Rapoport , Yang Shi , Vlastimil Babka , Nadav Amit , Andrea Arcangeli , Peter Xu , linux-mm@kvack.org, x86@kernel.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, David Hildenbrand , Huacai Chen , WANG Xuerui Subject: [PATCH mm-unstable RFC 08/26] loongarch/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE Date: Tue, 6 Dec 2022 15:47:12 +0100 Message-Id: <20221206144730.163732-9-david@redhat.com> In-Reply-To: <20221206144730.163732-1-david@redhat.com> References: <20221206144730.163732-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the type. Generic MM currently only uses 5 bits for the type (MAX_SWAPFILES_SHIFT), so the stolen bit is effectively unused. While at it, also mask the type in mk_swap_pte(). Note that this bit does not conflict with swap PMDs and could also be used in swap PMD context later. Cc: Huacai Chen Cc: WANG Xuerui Signed-off-by: David Hildenbrand --- arch/loongarch/include/asm/pgtable-bits.h | 4 +++ arch/loongarch/include/asm/pgtable.h | 39 ++++++++++++++++++++--- 2 files changed, 39 insertions(+), 4 deletions(-) diff --git a/arch/loongarch/include/asm/pgtable-bits.h b/arch/loongarch/include/asm/pgtable-bits.h index 3d1e0a69975a..8b98d22a145b 100644 --- a/arch/loongarch/include/asm/pgtable-bits.h +++ b/arch/loongarch/include/asm/pgtable-bits.h @@ -20,6 +20,7 @@ #define _PAGE_SPECIAL_SHIFT 11 #define _PAGE_HGLOBAL_SHIFT 12 /* HGlobal is a PMD bit */ #define _PAGE_PFN_SHIFT 12 +#define _PAGE_SWP_EXCLUSIVE_SHIFT 23 #define _PAGE_PFN_END_SHIFT 48 #define _PAGE_NO_READ_SHIFT 61 #define _PAGE_NO_EXEC_SHIFT 62 @@ -33,6 +34,9 @@ #define _PAGE_PROTNONE (_ULCAST_(1) << _PAGE_PROTNONE_SHIFT) #define _PAGE_SPECIAL (_ULCAST_(1) << _PAGE_SPECIAL_SHIFT) +/* We borrow bit 23 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE (_ULCAST_(1) << _PAGE_SWP_EXCLUSIVE_SHIFT) + /* Used by TLB hardware (placed in EntryLo*) */ #define _PAGE_VALID (_ULCAST_(1) << _PAGE_VALID_SHIFT) #define _PAGE_DIRTY (_ULCAST_(1) << _PAGE_DIRTY_SHIFT) diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h index 022ec6be3602..70d037c957a4 100644 --- a/arch/loongarch/include/asm/pgtable.h +++ b/arch/loongarch/include/asm/pgtable.h @@ -249,13 +249,26 @@ extern void pud_init(void *addr); extern void pmd_init(void *addr); /* - * Non-present pages: high 40 bits are offset, next 8 bits type, - * low 16 bits zero. + * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that + * are !pte_none() && !pte_present(). + * + * Format of swap PTEs: + * + * 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3 + * 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 + * <--------------------------- offset --------------------------- + * + * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 + * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 + * --------------> E <--- type ---> <---------- zeroes ----------> + * + * E is the exclusive marker that is not stored in swap entries. + * The zero'ed bits include _PAGE_PRESENT and _PAGE_PROTNONE. */ static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset) -{ pte_t pte; pte_val(pte) = (type << 16) | (offset << 24); return pte; } +{ pte_t pte; pte_val(pte) = ((type & 0x7f) << 16) | (offset << 24); return pte; } -#define __swp_type(x) (((x).val >> 16) & 0xff) +#define __swp_type(x) (((x).val >> 16) & 0x7f) #define __swp_offset(x) ((x).val >> 24) #define __swp_entry(type, offset) ((swp_entry_t) { pte_val(mk_swap_pte((type), (offset))) }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) @@ -263,6 +276,24 @@ static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset) #define __pmd_to_swp_entry(pmd) ((swp_entry_t) { pmd_val(pmd) }) #define __swp_entry_to_pmd(x) ((pmd_t) { (x).val | _PAGE_HUGE }) +#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE +static inline int pte_swp_exclusive(pte_t pte) +{ + return pte_val(pte) & _PAGE_SWP_EXCLUSIVE; +} + +static inline pte_t pte_swp_mkexclusive(pte_t pte) +{ + pte_val(pte) |= _PAGE_SWP_EXCLUSIVE; + return pte; +} + +static inline pte_t pte_swp_clear_exclusive(pte_t pte) +{ + pte_val(pte) &= ~_PAGE_SWP_EXCLUSIVE; + return pte; +} + extern void paging_init(void); #define pte_none(pte) (!(pte_val(pte) & ~_PAGE_GLOBAL))