From patchwork Tue Dec 6 14:47:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13065950 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 8D48DC47090 for ; Tue, 6 Dec 2022 14:53:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235351AbiLFOxq (ORCPT ); Tue, 6 Dec 2022 09:53:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45310 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235309AbiLFOw5 (ORCPT ); Tue, 6 Dec 2022 09:52:57 -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 A9DD92EF7B for ; Tue, 6 Dec 2022 06:49:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670338164; 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=WzoZqZ/9WlcO6V298YVqkPqgyDG5UMzG+Jr2DTFd0D0=; b=LSYas8jEX5bFxM+tTlaCLkFyRQj1aqB8VnEZStjHD7isWyLQz7gsdMDwdvg6KBuffTtwnh LluoBLbyue4vkqnwMxvY86aUcnP6MoUjylV1ZV4txJiCh6RSk6Mez4LJbOm6b+0cy0kKlg QkKZcwyYeDPoor8Bphux/VD0NEkjT5E= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-341-dlVVBPaEOQe7_S9LFwWrNw-1; Tue, 06 Dec 2022 09:49:23 -0500 X-MC-Unique: dlVVBPaEOQe7_S9LFwWrNw-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 F1A5438164D9; Tue, 6 Dec 2022 14:49:21 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2826F492B07; Tue, 6 Dec 2022 14:49:15 +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 , Thomas Bogendoerfer Subject: [PATCH mm-unstable RFC 12/26] mips/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE Date: Tue, 6 Dec 2022 15:47:16 +0100 Message-Id: <20221206144730.163732-13-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-sh@vger.kernel.org Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE. On 64bit, steal 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. On 32bit we're able to locate unused bits. As the PTE layout for 32 bit is very confusing, document it a bit better. While at it, mask the type in __swp_entry()/mk_swap_pte(). Cc: Thomas Bogendoerfer Signed-off-by: David Hildenbrand --- arch/mips/include/asm/pgtable-32.h | 86 ++++++++++++++++++++++++++---- arch/mips/include/asm/pgtable-64.h | 23 ++++++-- arch/mips/include/asm/pgtable.h | 36 +++++++++++++ 3 files changed, 130 insertions(+), 15 deletions(-) diff --git a/arch/mips/include/asm/pgtable-32.h b/arch/mips/include/asm/pgtable-32.h index b40a0e69fccc..c2a3b899480c 100644 --- a/arch/mips/include/asm/pgtable-32.h +++ b/arch/mips/include/asm/pgtable-32.h @@ -191,42 +191,103 @@ static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot) #define pte_page(x) pfn_to_page(pte_pfn(x)) +/* + * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that + * are !pte_none() && !pte_present(). + */ #if defined(CONFIG_CPU_R3K_TLB) -/* Swap entries must have VALID bit cleared. */ +/* + * Format of swap PTEs: + * + * 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 + * <----------- offset ------------> < type -> V G E 0 0 0 0 0 0 P + * + * E is the exclusive marker that is not stored in swap entries. + * _PAGE_PRESENT (P), _PAGE_VALID (V) and_PAGE_GLOBAL (G) have to remain + * unused. + */ #define __swp_type(x) (((x).val >> 10) & 0x1f) #define __swp_offset(x) ((x).val >> 15) -#define __swp_entry(type,offset) ((swp_entry_t) { ((type) << 10) | ((offset) << 15) }) +#define __swp_entry(type,offset) ((swp_entry_t) { (((type) & 0x1f) << 10) | ((offset) << 15) }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) +/* We borrow bit 7 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE (1 << 7) + #else #if defined(CONFIG_XPA) -/* Swap entries must have VALID and GLOBAL bits cleared. */ +/* + * 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 + * 0 0 0 0 0 0 E P <------------------ zeroes -------------------> + * + * 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 + * <----------------- offset ------------------> < type -> V G 0 0 + * + * E is the exclusive marker that is not stored in swap entries. + * _PAGE_PRESENT (P), _PAGE_VALID (V) and_PAGE_GLOBAL (G) have to remain + * unused. + */ #define __swp_type(x) (((x).val >> 4) & 0x1f) #define __swp_offset(x) ((x).val >> 9) -#define __swp_entry(type,offset) ((swp_entry_t) { ((type) << 4) | ((offset) << 9) }) +#define __swp_entry(type,offset) ((swp_entry_t) { (((type) & 0x1f) << 4) | ((offset) << 9) }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { (pte).pte_high }) #define __swp_entry_to_pte(x) ((pte_t) { 0, (x).val }) +/* + * We borrow bit 57 (bit 25 in the low PTE) to store the exclusive marker in + * swap PTEs. + */ +#define _PAGE_SWP_EXCLUSIVE (1 << 25) + #elif defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32) -/* Swap entries must have VALID and GLOBAL bits cleared. */ +/* + * 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 + * <------------------ zeroes -------------------> E P 0 0 0 0 0 0 + * + * 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 + * <------------------- offset --------------------> < type -> V G + * + * E is the exclusive marker that is not stored in swap entries. + * _PAGE_PRESENT (P), _PAGE_VALID (V) and_PAGE_GLOBAL (G) have to remain + * unused. + */ #define __swp_type(x) (((x).val >> 2) & 0x1f) #define __swp_offset(x) ((x).val >> 7) -#define __swp_entry(type, offset) ((swp_entry_t) { ((type) << 2) | ((offset) << 7) }) +#define __swp_entry(type, offset) ((swp_entry_t) { (((type) & 0x1f) << 2) | ((offset) << 7) }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { (pte).pte_high }) #define __swp_entry_to_pte(x) ((pte_t) { 0, (x).val }) +/* + * We borrow bit 39 (bit 7 in the low PTE) to store the exclusive marker in swap + * PTEs. + */ +#define _PAGE_SWP_EXCLUSIVE (1 << 7) + #else /* - * Constraints: - * _PAGE_PRESENT at bit 0 - * _PAGE_MODIFIED at bit 4 - * _PAGE_GLOBAL at bit 6 - * _PAGE_VALID at bit 7 + * Format of swap PTEs: + * + * 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 + * <------------- offset --------------> < type -> 0 0 0 0 0 0 E P + * + * E is the exclusive marker that is not stored in swap entries. + * _PAGE_PRESENT (P), _PAGE_VALID (V) and_PAGE_GLOBAL (G) have to remain + * unused. The location of V and G varies. */ #define __swp_type(x) (((x).val >> 8) & 0x1f) #define __swp_offset(x) ((x).val >> 13) @@ -234,6 +295,9 @@ static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) +/* We borrow bit 1 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE (1 << 1) + #endif /* defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32) */ #endif /* defined(CONFIG_CPU_R3K_TLB) */ diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgtable-64.h index c6310192b654..98e24e3e7f2b 100644 --- a/arch/mips/include/asm/pgtable-64.h +++ b/arch/mips/include/asm/pgtable-64.h @@ -320,16 +320,31 @@ 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. */ 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) }) #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) +/* We borrow bit 23 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE (1 << 23) + #endif /* _ASM_PGTABLE_64_H */ diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h index a68c0b01d8cd..711874cee8e4 100644 --- a/arch/mips/include/asm/pgtable.h +++ b/arch/mips/include/asm/pgtable.h @@ -528,6 +528,42 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) } #endif +#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE +#if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32) +static inline int pte_swp_exclusive(pte_t pte) +{ + return pte.pte_low & _PAGE_SWP_EXCLUSIVE; +} + +static inline pte_t pte_swp_mkexclusive(pte_t pte) +{ + pte.pte_low |= _PAGE_SWP_EXCLUSIVE; + return pte; +} + +static inline pte_t pte_swp_clear_exclusive(pte_t pte) +{ + pte.pte_low &= ~_PAGE_SWP_EXCLUSIVE; + return pte; +} +#else +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; +} +#endif extern void __update_tlb(struct vm_area_struct *vma, unsigned long address, pte_t pte);