From patchwork Tue Jun 1 23:22:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lin X-Patchwork-Id: 12292427 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 19D3FC47093 for ; Tue, 1 Jun 2021 23:22:39 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 904DD613C0 for ; Tue, 1 Jun 2021 23:22:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 904DD613C0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 49EE96B006C; Tue, 1 Jun 2021 19:22:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 42C4F6B0071; Tue, 1 Jun 2021 19:22:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 208B56B006E; Tue, 1 Jun 2021 19:22:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0119.hostedemail.com [216.40.44.119]) by kanga.kvack.org (Postfix) with ESMTP id D64196B006E for ; Tue, 1 Jun 2021 19:22:36 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 61A236129 for ; Tue, 1 Jun 2021 23:22:36 +0000 (UTC) X-FDA: 78206731512.08.0D58F5A Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf17.hostedemail.com (Postfix) with ESMTP id F3EF84202A07 for ; Tue, 1 Jun 2021 23:22:26 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 33F4761396; Tue, 1 Jun 2021 23:22:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622589755; bh=/uKKR8u1AHOQjBwcyVTzk/1UAcLGgZWy4Bb+xUC5YIk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sRja1mt022qtedKaIMuXmoumyP0IS62eYwap3qR7HCsavXo184zPIhUqrd1xmqL1w HTNbI81IKyD9EOYkp7yHB0Qkz+hWTv7ggbj5S4DffxQNyaotjnfp8pHbShQfT8ioI9 aOIxeWDTJxe6Fhfx++1YwMbYcxQfn+TZ7+ef3myjfbCaASGms3xhgPVHwkRMjCHG1z LwrTttvUcQyVcDH1lzOULoTzwqhiV1jA0D8xnZl5NxHhI3llVwvhfhq1rJqJ8EDKtU oNf3K44C4/8rcmQ20apxe9ees82QntAyd6HiREBdDh7rYCMTkDrKQ8LlwnB9KS+wXL 9dENEjHpXwyeA== From: Ming Lin To: Linus Torvalds , Hugh Dickins , Simon Ser Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ming Lin Subject: [PATCH 1/2] mm: make "vm_flags" be an u64 Date: Tue, 1 Jun 2021 16:22:32 -0700 Message-Id: <1622589753-9206-2-git-send-email-mlin@kernel.org> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1622589753-9206-1-git-send-email-mlin@kernel.org> References: <1622589753-9206-1-git-send-email-mlin@kernel.org> X-Rspamd-Queue-Id: F3EF84202A07 Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=sRja1mt0; spf=pass (imf17.hostedemail.com: domain of mlin@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=mlin@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-Rspamd-Server: rspam04 X-Stat-Signature: jfdz7kaywefpbdu7cp7wzfgcyx9e8o3y X-HE-Tag: 1622589746-534205 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: So we can have enough bits on 32-bit architectures. Signed-off-by: Ming Lin Reported-by: kernel test robot Reported-by: kernel test robot --- arch/arm64/Kconfig | 1 - arch/powerpc/Kconfig | 1 - arch/x86/Kconfig | 1 - include/linux/mm.h | 100 ++++++++++++++++++++++------------------------- include/linux/mm_types.h | 4 +- include/linux/mman.h | 4 +- mm/Kconfig | 2 - mm/memory.c | 2 +- mm/mmap.c | 2 +- 9 files changed, 53 insertions(+), 64 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 9f1d856..c6960ea 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1658,7 +1658,6 @@ config ARM64_MTE depends on AS_HAS_LSE_ATOMICS # Required for tag checking in the uaccess routines depends on ARM64_PAN - select ARCH_USES_HIGH_VMA_FLAGS help Memory Tagging (part of the ARMv8.5 Extensions) provides architectural support for run-time, always-on detection of diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 088dd2a..5c1b49e 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -940,7 +940,6 @@ config PPC_MEM_KEYS prompt "PowerPC Memory Protection Keys" def_bool y depends on PPC_BOOK3S_64 - select ARCH_USES_HIGH_VMA_FLAGS select ARCH_HAS_PKEYS help Memory Protection Keys provides a mechanism for enforcing diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 0045e1b..a885336 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1874,7 +1874,6 @@ config X86_INTEL_MEMORY_PROTECTION_KEYS def_bool y # Note: only available in 64-bit mode depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD) - select ARCH_USES_HIGH_VMA_FLAGS select ARCH_HAS_PKEYS help Memory Protection Keys provides a mechanism for enforcing diff --git a/include/linux/mm.h b/include/linux/mm.h index c274f75..e9d67bc 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -264,73 +264,68 @@ int __add_to_page_cache_locked(struct page *page, struct address_space *mapping, extern unsigned int kobjsize(const void *objp); #endif +#define VM_FLAGS_BIT(N) (1ULL << (N)) + /* * vm_flags in vm_area_struct, see mm_types.h. * When changing, update also include/trace/events/mmflags.h */ #define VM_NONE 0x00000000 -#define VM_READ 0x00000001 /* currently active flags */ -#define VM_WRITE 0x00000002 -#define VM_EXEC 0x00000004 -#define VM_SHARED 0x00000008 +#define VM_READ VM_FLAGS_BIT(0) /* currently active flags */ +#define VM_WRITE VM_FLAGS_BIT(1) +#define VM_EXEC VM_FLAGS_BIT(2) +#define VM_SHARED VM_FLAGS_BIT(3) /* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */ -#define VM_MAYREAD 0x00000010 /* limits for mprotect() etc */ -#define VM_MAYWRITE 0x00000020 -#define VM_MAYEXEC 0x00000040 -#define VM_MAYSHARE 0x00000080 - -#define VM_GROWSDOWN 0x00000100 /* general info on the segment */ -#define VM_UFFD_MISSING 0x00000200 /* missing pages tracking */ -#define VM_PFNMAP 0x00000400 /* Page-ranges managed without "struct page", just pure PFN */ -#define VM_DENYWRITE 0x00000800 /* ETXTBSY on write attempts.. */ -#define VM_UFFD_WP 0x00001000 /* wrprotect pages tracking */ - -#define VM_LOCKED 0x00002000 -#define VM_IO 0x00004000 /* Memory mapped I/O or similar */ - - /* Used by sys_madvise() */ -#define VM_SEQ_READ 0x00008000 /* App will access data sequentially */ -#define VM_RAND_READ 0x00010000 /* App will not benefit from clustered reads */ - -#define VM_DONTCOPY 0x00020000 /* Do not copy this vma on fork */ -#define VM_DONTEXPAND 0x00040000 /* Cannot expand with mremap() */ -#define VM_LOCKONFAULT 0x00080000 /* Lock the pages covered when they are faulted in */ -#define VM_ACCOUNT 0x00100000 /* Is a VM accounted object */ -#define VM_NORESERVE 0x00200000 /* should the VM suppress accounting */ -#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */ -#define VM_SYNC 0x00800000 /* Synchronous page faults */ -#define VM_ARCH_1 0x01000000 /* Architecture-specific flag */ -#define VM_WIPEONFORK 0x02000000 /* Wipe VMA contents in child. */ -#define VM_DONTDUMP 0x04000000 /* Do not include in the core dump */ +#define VM_MAYREAD VM_FLAGS_BIT(4) /* limits for mprotect() etc */ +#define VM_MAYWRITE VM_FLAGS_BIT(5) +#define VM_MAYEXEC VM_FLAGS_BIT(6) +#define VM_MAYSHARE VM_FLAGS_BIT(7) + +#define VM_GROWSDOWN VM_FLAGS_BIT(8) /* general info on the segment */ +#define VM_UFFD_MISSING VM_FLAGS_BIT(9) /* missing pages tracking */ +#define VM_PFNMAP VM_FLAGS_BIT(10) /* Page-ranges managed without "struct page", just pure PFN */ +#define VM_DENYWRITE VM_FLAGS_BIT(11) /* ETXTBSY on write attempts.. */ +#define VM_UFFD_WP VM_FLAGS_BIT(12) /* wrprotect pages tracking */ + +#define VM_LOCKED VM_FLAGS_BIT(13) +#define VM_IO VM_FLAGS_BIT(14) /* Memory mapped I/O or similar */ + + /* Used by sys_madvise() */ +#define VM_SEQ_READ VM_FLAGS_BIT(15) /* App will access data sequentially */ +#define VM_RAND_READ VM_FLAGS_BIT(16) /* App will not benefit from clustered reads */ + +#define VM_DONTCOPY VM_FLAGS_BIT(17) /* Do not copy this vma on fork */ +#define VM_DONTEXPAND VM_FLAGS_BIT(18) /* Cannot expand with mremap() */ +#define VM_LOCKONFAULT VM_FLAGS_BIT(19) /* Lock the pages covered when they are faulted in */ +#define VM_ACCOUNT VM_FLAGS_BIT(20) /* Is a VM accounted object */ +#define VM_NORESERVE VM_FLAGS_BIT(21) /* should the VM suppress accounting */ +#define VM_HUGETLB VM_FLAGS_BIT(22) /* Huge TLB Page VM */ +#define VM_SYNC VM_FLAGS_BIT(23) /* Synchronous page faults */ +#define VM_ARCH_1 VM_FLAGS_BIT(24) /* Architecture-specific flag */ +#define VM_WIPEONFORK VM_FLAGS_BIT(25) /* Wipe VMA contents in child. */ +#define VM_DONTDUMP VM_FLAGS_BIT(26) /* Do not include in the core dump */ #ifdef CONFIG_MEM_SOFT_DIRTY -# define VM_SOFTDIRTY 0x08000000 /* Not soft dirty clean area */ +# define VM_SOFTDIRTY VM_FLAGS_BIT(27) /* Not soft dirty clean area */ #else # define VM_SOFTDIRTY 0 #endif -#define VM_MIXEDMAP 0x10000000 /* Can contain "struct page" and pure PFN pages */ -#define VM_HUGEPAGE 0x20000000 /* MADV_HUGEPAGE marked this vma */ -#define VM_NOHUGEPAGE 0x40000000 /* MADV_NOHUGEPAGE marked this vma */ -#define VM_MERGEABLE 0x80000000 /* KSM may merge identical pages */ - -#ifdef CONFIG_ARCH_USES_HIGH_VMA_FLAGS -#define VM_HIGH_ARCH_BIT_0 32 /* bit only usable on 64-bit architectures */ -#define VM_HIGH_ARCH_BIT_1 33 /* bit only usable on 64-bit architectures */ -#define VM_HIGH_ARCH_BIT_2 34 /* bit only usable on 64-bit architectures */ -#define VM_HIGH_ARCH_BIT_3 35 /* bit only usable on 64-bit architectures */ -#define VM_HIGH_ARCH_BIT_4 36 /* bit only usable on 64-bit architectures */ -#define VM_HIGH_ARCH_0 BIT(VM_HIGH_ARCH_BIT_0) -#define VM_HIGH_ARCH_1 BIT(VM_HIGH_ARCH_BIT_1) -#define VM_HIGH_ARCH_2 BIT(VM_HIGH_ARCH_BIT_2) -#define VM_HIGH_ARCH_3 BIT(VM_HIGH_ARCH_BIT_3) -#define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4) -#endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */ +#define VM_MIXEDMAP VM_FLAGS_BIT(28) /* Can contain "struct page" and pure PFN pages */ +#define VM_HUGEPAGE VM_FLAGS_BIT(29) /* MADV_HUGEPAGE marked this vma */ +#define VM_NOHUGEPAGE VM_FLAGS_BIT(30) /* MADV_NOHUGEPAGE marked this vma */ +#define VM_MERGEABLE VM_FLAGS_BIT(31) /* KSM may merge identical pages */ + +#define VM_HIGH_ARCH_0 VM_FLAGS_BIT(32) +#define VM_HIGH_ARCH_1 VM_FLAGS_BIT(33) +#define VM_HIGH_ARCH_2 VM_FLAGS_BIT(34) +#define VM_HIGH_ARCH_3 VM_FLAGS_BIT(35) +#define VM_HIGH_ARCH_4 VM_FLAGS_BIT(36) #ifdef CONFIG_ARCH_HAS_PKEYS -# define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0 +# define VM_PKEY_SHIFT 32 # define VM_PKEY_BIT0 VM_HIGH_ARCH_0 /* A protection key is a 4-bit value */ # define VM_PKEY_BIT1 VM_HIGH_ARCH_1 /* on x86 and 5-bit value on ppc64 */ # define VM_PKEY_BIT2 VM_HIGH_ARCH_2 @@ -373,8 +368,7 @@ int __add_to_page_cache_locked(struct page *page, struct address_space *mapping, #endif #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR -# define VM_UFFD_MINOR_BIT 37 -# define VM_UFFD_MINOR BIT(VM_UFFD_MINOR_BIT) /* UFFD minor faults */ +# define VM_UFFD_MINOR VM_FLAGS_BIT(37) /* UFFD minor faults */ #else /* !CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ # define VM_UFFD_MINOR VM_NONE #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 5aacc1c..5347293 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -264,7 +264,7 @@ struct page_frag_cache { bool pfmemalloc; }; -typedef unsigned long vm_flags_t; +typedef u64 vm_flags_t; /* * A region containing a mapping of a non-memory backed file under NOMMU @@ -330,7 +330,7 @@ struct vm_area_struct { * See vmf_insert_mixed_prot() for discussion. */ pgprot_t vm_page_prot; - unsigned long vm_flags; /* Flags, see mm.h. */ + vm_flags_t vm_flags; /* Flags, see mm.h. */ /* * For areas with an address space and backing store, diff --git a/include/linux/mman.h b/include/linux/mman.h index 629cefc..b2cbae9 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -135,7 +135,7 @@ static inline bool arch_validate_flags(unsigned long flags) /* * Combine the mmap "prot" argument into "vm_flags" used internally. */ -static inline unsigned long +static inline vm_flags_t calc_vm_prot_bits(unsigned long prot, unsigned long pkey) { return _calc_vm_trans(prot, PROT_READ, VM_READ ) | @@ -147,7 +147,7 @@ static inline bool arch_validate_flags(unsigned long flags) /* * Combine the mmap "flags" argument into "vm_flags" used internally. */ -static inline unsigned long +static inline vm_flags_t calc_vm_flag_bits(unsigned long flags) { return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) | diff --git a/mm/Kconfig b/mm/Kconfig index 02d44e3..aa8efba 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -830,8 +830,6 @@ config DEVICE_PRIVATE config VMAP_PFN bool -config ARCH_USES_HIGH_VMA_FLAGS - bool config ARCH_HAS_PKEYS bool diff --git a/mm/memory.c b/mm/memory.c index 730daa0..eff2a47 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -550,7 +550,7 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, (long long)pte_val(pte), (long long)pmd_val(*pmd)); if (page) dump_page(page, "bad pte"); - pr_alert("addr:%px vm_flags:%08lx anon_vma:%px mapping:%px index:%lx\n", + pr_alert("addr:%px vm_flags:%08llx anon_vma:%px mapping:%px index:%lx\n", (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); pr_alert("file:%pD fault:%ps mmap:%ps readpage:%ps\n", vma->vm_file, diff --git a/mm/mmap.c b/mm/mmap.c index 0584e54..096bba4 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1353,7 +1353,7 @@ static inline unsigned long round_hint_to_min(unsigned long hint) } static inline int mlock_future_check(struct mm_struct *mm, - unsigned long flags, + vm_flags_t flags, unsigned long len) { unsigned long locked, lock_limit; From patchwork Tue Jun 1 23:22:33 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lin X-Patchwork-Id: 12292429 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 8D47EC4708F for ; Tue, 1 Jun 2021 23:22:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 420DA613CC for ; Tue, 1 Jun 2021 23:22:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 420DA613CC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6EEF46B006E; Tue, 1 Jun 2021 19:22:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 64E2A6B0072; Tue, 1 Jun 2021 19:22:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 403E76B0074; Tue, 1 Jun 2021 19:22:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0076.hostedemail.com [216.40.44.76]) by kanga.kvack.org (Postfix) with ESMTP id 0469C6B006C for ; Tue, 1 Jun 2021 19:22:36 -0400 (EDT) Received: from smtpin39.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 93B916137 for ; Tue, 1 Jun 2021 23:22:36 +0000 (UTC) X-FDA: 78206731512.39.952350F Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf12.hostedemail.com (Postfix) with ESMTP id 1B1463C3 for ; Tue, 1 Jun 2021 23:22:19 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 69192613BC; Tue, 1 Jun 2021 23:22:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622589755; bh=d6j6EDGkhnc+GxiEmiU29Lm/NCKNEqKbXTPVfNJiuuM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ftu0zJj3/weUgRsC8CSXzsmqeuhN2FdlfFbM5ew8+E1xgWmbSx50aC2TeDff/fo3r rXK/4YMRtWDpxZ50xfhXMJM3yljE5igxQ6kcRa58MomH/F5L3TNhL/t884dtSmTIo+ 09ytxS7PJVtcn5dj3yw4PyjcYw2tGvkIVW8OQ6ZWZD48lgYqOpLsFdXQDLWjTH9P85 7oHZbbIgqE5qoxr3gzF+FM4CckTHXQRscojVBqXI2wgPvH8I2utWPqJdlz5LQ+N7pT TM+e02mUxQEZMPM0EBBBYG3z5XlVgjf55p6Q/I8nuq6tynxWktFEIPZ5FcbLpVVNog E77bBQpTQwZTw== From: Ming Lin To: Linus Torvalds , Hugh Dickins , Simon Ser Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ming Lin Subject: [PATCH 2/2] mm: adds NOSIGBUS extension for out-of-band shmem read Date: Tue, 1 Jun 2021 16:22:33 -0700 Message-Id: <1622589753-9206-3-git-send-email-mlin@kernel.org> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1622589753-9206-1-git-send-email-mlin@kernel.org> References: <1622589753-9206-1-git-send-email-mlin@kernel.org> Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ftu0zJj3; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf12.hostedemail.com: domain of mlin@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=mlin@kernel.org X-Stat-Signature: 3w6ya9j687i6bsoc45e7n4zoyhhbst1g X-Rspamd-Queue-Id: 1B1463C3 X-Rspamd-Server: rspam02 X-HE-Tag: 1622589739-126602 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Adds new flag MAP_NOSIGBUS of mmap() to specify the behavior of "don't SIGBUS on read beyond i_size". This flag is only allowed for read only shmem mapping. If you use MAP_NOSIGBUS, and you access pages that don't have a backing store, you will get zero pages, and they will NOT BE SYNCHRONIZED with the backing store possibly later being updated. Any user that uses MAP_NOSIGBUS had better just accept that it's not compatible with expanding the shmem backing store later. Signed-off-by: Ming Lin Reported-by: kernel test robot Reported-by: kernel test robot --- include/linux/mm.h | 2 ++ include/linux/mman.h | 1 + include/uapi/asm-generic/mman-common.h | 1 + mm/mmap.c | 3 +++ mm/shmem.c | 17 ++++++++++++++++- 5 files changed, 23 insertions(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index e9d67bc..5d0e0dc 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -373,6 +373,8 @@ int __add_to_page_cache_locked(struct page *page, struct address_space *mapping, # define VM_UFFD_MINOR VM_NONE #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ +#define VM_NOSIGBUS VM_FLAGS_BIT(38) /* Do not SIGBUS on out-of-band shmem read */ + /* Bits set in the VMA until the stack is in its final location */ #define VM_STACK_INCOMPLETE_SETUP (VM_RAND_READ | VM_SEQ_READ) diff --git a/include/linux/mman.h b/include/linux/mman.h index b2cbae9..c966b08 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -154,6 +154,7 @@ static inline bool arch_validate_flags(unsigned long flags) _calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) | _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) | _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) | + _calc_vm_trans(flags, MAP_NOSIGBUS, VM_NOSIGBUS ) | arch_calc_vm_flag_bits(flags); } diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h index f94f65d..55f4be0 100644 --- a/include/uapi/asm-generic/mman-common.h +++ b/include/uapi/asm-generic/mman-common.h @@ -29,6 +29,7 @@ #define MAP_HUGETLB 0x040000 /* create a huge page mapping */ #define MAP_SYNC 0x080000 /* perform synchronous page faults for the mapping */ #define MAP_FIXED_NOREPLACE 0x100000 /* MAP_FIXED which doesn't unmap underlying mapping */ +#define MAP_NOSIGBUS 0x200000 /* do not SIGBUS on out-of-band shmem read */ #define MAP_UNINITIALIZED 0x4000000 /* For anonymous mmap, memory could be * uninitialized */ diff --git a/mm/mmap.c b/mm/mmap.c index 096bba4..69cd856 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1419,6 +1419,9 @@ unsigned long do_mmap(struct file *file, unsigned long addr, if (!len) return -EINVAL; + if ((flags & MAP_NOSIGBUS) && ((prot & PROT_WRITE) || !shmem_file(file))) + return -EINVAL; + /* * Does the application expect PROT_READ to imply PROT_EXEC? * diff --git a/mm/shmem.c b/mm/shmem.c index 5d46611..5d15b08 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1812,7 +1812,22 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, repeat: if (sgp <= SGP_CACHE && ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) { - return -EINVAL; + if (!vma || !(vma->vm_flags & VM_NOSIGBUS)) + return -EINVAL; + + vma->vm_flags |= VM_MIXEDMAP; + /* + * Get zero page for MAP_NOSIGBUS mapping, which isn't + * coherent wrt shmem contents that are expanded and + * filled in later. + */ + error = vm_insert_page(vma, (unsigned long)vmf->address, + ZERO_PAGE(0)); + if (error) + return error; + + *fault_type = VM_FAULT_NOPAGE; + return 0; } sbinfo = SHMEM_SB(inode->i_sb);