From patchwork Tue Dec 6 14:47:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13065983 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 71E06C4708C for ; Tue, 6 Dec 2022 14:55:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234901AbiLFOzJ (ORCPT ); Tue, 6 Dec 2022 09:55:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47744 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230233AbiLFOyW (ORCPT ); Tue, 6 Dec 2022 09:54:22 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9DB262F38A for ; Tue, 6 Dec 2022 06:49:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670338190; 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=kuoCXqI41tKeRtxy+fFnakdrRdYAxZc6qHdSFUCJ9d4=; b=g2OLdD7dqGq4VehZswqKPy0r8u/Uvq+qoxcP3GN3a0Jhx1/rQK4t14CtDeZzmuYXs9lHZH 8eZ93dRLHv1QW2lqvkDzQbE2amGPhloHz71c9PWyngXacbF0tW45ngvI1zRfO2g9krT0Ki zx8wLxm0ukzatmNU68wWz1FqNXbKnZE= 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-93-gCs1_qJJME-HbQBXxNOj-w-1; Tue, 06 Dec 2022 09:49:48 -0500 X-MC-Unique: gCs1_qJJME-HbQBXxNOj-w-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 AB98A833A06; Tue, 6 Dec 2022 14:49:46 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id DFD44492B04; Tue, 6 Dec 2022 14:49:40 +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 , "James E.J. Bottomley" , Helge Deller Subject: [PATCH mm-unstable RFC 16/26] parisc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE Date: Tue, 6 Dec 2022 15:47:20 +0100 Message-Id: <20221206144730.163732-17-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-parisc@vger.kernel.org Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by using the yet-unused _PAGE_ACCESSED location in the swap PTE. Looking at pte_present() and pte_none() checks, there seems to be no actual reason why we cannot use it: we only have to make sure we're not using _PAGE_PRESENT. Reusing this bit avoids having to steal one bit from the swap offset. Cc: "James E.J. Bottomley" Cc: Helge Deller Signed-off-by: David Hildenbrand --- arch/parisc/include/asm/pgtable.h | 41 ++++++++++++++++++++++++++++--- 1 file changed, 38 insertions(+), 3 deletions(-) diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h index bd09a44cfb2d..75115c8bf888 100644 --- a/arch/parisc/include/asm/pgtable.h +++ b/arch/parisc/include/asm/pgtable.h @@ -218,6 +218,9 @@ extern void __update_cache(pte_t pte); #define _PAGE_KERNEL_RWX (_PAGE_KERNEL_EXEC | _PAGE_WRITE) #define _PAGE_KERNEL (_PAGE_KERNEL_RO | _PAGE_WRITE) +/* We borrow bit 23 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE _PAGE_ACCESSED + /* The pgd/pmd contains a ptr (in phys addr space); since all pgds/pmds * are page-aligned, we don't care about the PAGE_OFFSET bits, except * for a few meta-information bits, so we shift the address to be @@ -394,17 +397,49 @@ extern void paging_init (void); #define update_mmu_cache(vms,addr,ptep) __update_cache(*ptep) -/* Encode and de-code a swap entry */ - +/* + * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that + * are !pte_none() && !pte_present(). + * + * Format of swap PTEs (32bit): + * + * 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 + * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + * <---------------- offset -----------------> P E < type -> + * + * E is the exclusive marker that is not stored in swap entries. + * _PAGE_PRESENT (P) must be 0. + * + * For the 64bit version, the offset is extended by 32bit. + */ #define __swp_type(x) ((x).val & 0x1f) #define __swp_offset(x) ( (((x).val >> 6) & 0x7) | \ (((x).val >> 8) & ~0x7) ) -#define __swp_entry(type, offset) ((swp_entry_t) { (type) | \ +#define __swp_entry(type, offset) ((swp_entry_t) { \ + ((type) & 0x1f) | \ ((offset & 0x7) << 6) | \ ((offset & ~0x7) << 8) }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) +#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; +} + static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) { pte_t pte;