From patchwork Thu Feb 20 08:42:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Santosh Sivaraj X-Patchwork-Id: 231058 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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 17C03C11D00 for ; Thu, 20 Feb 2020 08:43:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7736207FD for ; Thu, 20 Feb 2020 08:43:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=fossix-org.20150623.gappssmtp.com header.i=@fossix-org.20150623.gappssmtp.com header.b="s94zVd+q" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726865AbgBTInC (ORCPT ); Thu, 20 Feb 2020 03:43:02 -0500 Received: from mail-pl1-f193.google.com ([209.85.214.193]:39474 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726764AbgBTInC (ORCPT ); Thu, 20 Feb 2020 03:43:02 -0500 Received: by mail-pl1-f193.google.com with SMTP id g6so1280629plp.6 for ; Thu, 20 Feb 2020 00:43:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fossix-org.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=3gKgbuQ+qyW6cSoObrFJbrpeEDkVLaM+BEDocK6BCUQ=; b=s94zVd+qdhp6grErmY5Om0h7V3Zf02oLkoMoLb2t/AQywv7xojk7BWN7lnaefzDX4V fAy7b+AZfMB+PzeQJ0ZkzxrGXZJS6KOoo0X4sUuiDZUO6fxM8XfOafVJ3w+N7VtrJgzH FQ3BuAczsNhmzctG/kdf+0e2Yu9zAS1NkMyVvHt9GzDXEdhAOIOjVUMeVhpfwLO4M5E7 +VXpM7/rrYU+E2+Vz+PgJIZ8/4hOX0wHm3nI+Tb1gLD59Toer402jVvaBH/tee1eRrhB XcaW0MLfEaeLPuTf2Z5kxMPV3huqDBJyPVW0/F77Te52Fmtbj2mXO18AvjKeVPURj7bB btrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=3gKgbuQ+qyW6cSoObrFJbrpeEDkVLaM+BEDocK6BCUQ=; b=YNorxmZsmcZExrI3cW0f2JqeMfYKDz6ggmcR3dGAt/6JAwNUpDq0eKSz9RpcV0ZCwC 06xHCLBbnDTijJnyDlQ0gEIMkc8JQ86ZRKBc13JZ4TYJzXNkNuDRxDdLu7qC0pLV6f2l pgXkXhQKQaztu56QgYD3Xm3gwjsuTDUDDsH9TwE590Lkd+qxh9Gr1nor7pXd60EgnrhH mAJZmNeEbf140aDrYgirdJtZYGQXR1tJxjtlPYkcfJzpnwwySZDVZn/HoeL+Qv+llMRU iMjRpU5AosKa0tRLvCyTCIkSXhPTuu+B/M8B5nMCMrVsXo4xYA23DHYtCKUw7INChzSU 9xeA== X-Gm-Message-State: APjAAAU8Xt2/IkG//+zJcK/b8AUq7nSYw5ZUbjTYE0CaR3epzz6qnUE5 r/uyMajckXnQ+QdsyWPX2qvLOAnv/Qo= X-Google-Smtp-Source: APXvYqyRBfvUbgHm/BRv3pVhx5sTcraF9XyZo4Mho4MdiH1Tp0615HezjwCAFENHyx5dXPgJ8yqeMg== X-Received: by 2002:a17:90b:30c9:: with SMTP id hi9mr2250522pjb.81.1582188181592; Thu, 20 Feb 2020 00:43:01 -0800 (PST) Received: from santosiv.in.ibm.com ([129.41.84.72]) by smtp.gmail.com with ESMTPSA id r145sm2512381pfr.5.2020.02.20.00.42.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Feb 2020 00:43:01 -0800 (PST) From: Santosh Sivaraj To: linuxppc-dev , stable@vger.kernel.org Cc: peterz@infradead.org, aneesh.kumar@linux.ibm.com, akshay.adiga@linux.ibm.com, gregkh@linuxfoundation.org Subject: [PATCH 4/6] powerpc/mmu_gather: enable RCU_TABLE_FREE even for !SMP case Date: Thu, 20 Feb 2020 14:12:27 +0530 Message-Id: <20200220084229.1278137-5-santosh@fossix.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200220084229.1278137-1-santosh@fossix.org> References: <20200220084229.1278137-1-santosh@fossix.org> MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: "Aneesh Kumar K.V" Patch series "Fixup page directory freeing", v4. This is a repost of patch series from Peter with the arch specific changes except ppc64 dropped. ppc64 changes are added here because we are redoing the patch series on top of ppc64 changes. This makes it easy to backport these changes. Only the first 2 patches need to be backported to stable. The thing is, on anything SMP, freeing page directories should observe the exact same order as normal page freeing: 1) unhook page/directory 2) TLB invalidate 3) free page/directory Without this, any concurrent page-table walk could end up with a Use-after-Free. This is esp. trivial for anything that has software page-table walkers (HAVE_FAST_GUP / software TLB fill) or the hardware caches partial page-walks (ie. caches page directories). Even on UP this might give issues since mmu_gather is preemptible these days. An interrupt or preempted task accessing user pages might stumble into the free page if the hardware caches page directories. This patch series fixes ppc64 and add generic MMU_GATHER changes to support the conversion of other architectures. I haven't added patches w.r.t other architecture because they are yet to be acked. This patch (of 9): A followup patch is going to make sure we correctly invalidate page walk cache before we free page table pages. In order to keep things simple enable RCU_TABLE_FREE even for !SMP so that we don't have to fixup the !SMP case differently in the followup patch !SMP case is right now broken for radix translation w.r.t page walk cache flush. We can get interrupted in between page table free and that would imply we have page walk cache entries pointing to tables which got freed already. Michael said "both our platforms that run on Power9 force SMP on in Kconfig, so the !SMP case is unlikely to be a problem for anyone in practice, unless they've hacked their kernel to build it !SMP." 12e4d53f3f04e in upstream. Link: http://lkml.kernel.org/r/20200116064531.483522-2-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Cc: # 4.19 Signed-off-by: Santosh Sivaraj [santosh: backported for 4.19 stable] --- arch/powerpc/Kconfig | 2 +- arch/powerpc/include/asm/book3s/32/pgalloc.h | 8 -------- arch/powerpc/include/asm/book3s/64/pgalloc.h | 2 -- arch/powerpc/mm/pgtable-book3s64.c | 7 ------- 4 files changed, 1 insertion(+), 18 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index f7f046ff6407..fa231130eee1 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -215,7 +215,7 @@ config PPC select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !HAVE_HARDLOCKUP_DETECTOR_ARCH select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP - select HAVE_RCU_TABLE_FREE if SMP + select HAVE_RCU_TABLE_FREE select HAVE_RCU_TABLE_NO_INVALIDATE if HAVE_RCU_TABLE_FREE select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_RELIABLE_STACKTRACE if PPC64 && CPU_LITTLE_ENDIAN diff --git a/arch/powerpc/include/asm/book3s/32/pgalloc.h b/arch/powerpc/include/asm/book3s/32/pgalloc.h index 82e44b1a00ae..79ba3fbb512e 100644 --- a/arch/powerpc/include/asm/book3s/32/pgalloc.h +++ b/arch/powerpc/include/asm/book3s/32/pgalloc.h @@ -110,7 +110,6 @@ static inline void pgtable_free(void *table, unsigned index_size) #define check_pgt_cache() do { } while (0) #define get_hugepd_cache_index(x) (x) -#ifdef CONFIG_SMP static inline void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift) { @@ -127,13 +126,6 @@ static inline void __tlb_remove_table(void *_table) pgtable_free(table, shift); } -#else -static inline void pgtable_free_tlb(struct mmu_gather *tlb, - void *table, int shift) -{ - pgtable_free(table, shift); -} -#endif static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table, unsigned long address) diff --git a/arch/powerpc/include/asm/book3s/64/pgalloc.h b/arch/powerpc/include/asm/book3s/64/pgalloc.h index f9019b579903..1013c0214213 100644 --- a/arch/powerpc/include/asm/book3s/64/pgalloc.h +++ b/arch/powerpc/include/asm/book3s/64/pgalloc.h @@ -47,9 +47,7 @@ extern pmd_t *pmd_fragment_alloc(struct mm_struct *, unsigned long); extern void pte_fragment_free(unsigned long *, int); extern void pmd_fragment_free(unsigned long *); extern void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift); -#ifdef CONFIG_SMP extern void __tlb_remove_table(void *_table); -#endif static inline pgd_t *radix__pgd_alloc(struct mm_struct *mm) { diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c index 297db665d953..5b4e9fd8990c 100644 --- a/arch/powerpc/mm/pgtable-book3s64.c +++ b/arch/powerpc/mm/pgtable-book3s64.c @@ -432,7 +432,6 @@ static inline void pgtable_free(void *table, int index) } } -#ifdef CONFIG_SMP void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int index) { unsigned long pgf = (unsigned long)table; @@ -449,12 +448,6 @@ void __tlb_remove_table(void *_table) return pgtable_free(table, index); } -#else -void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int index) -{ - return pgtable_free(table, index); -} -#endif #ifdef CONFIG_PROC_FS atomic_long_t direct_pages_count[MMU_PAGE_COUNT];