From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4EDBD223C67; Thu, 12 Dec 2024 17:14:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734023641; cv=none; b=KXZ4xbCjJl2fndse77RBOnDoZswC/cJ36VThlIKD9heBVAT+GuhswpE+KySpB7el5UulByd3dIZMJ5FYTqhbMGlliIj48YT50suTrJ84MXMJd3Zd+bmudPtIs0NyhFz1UddShptPHY9g9LhOZmwCmK5rT8Ff8jDknMUlN0UCyus= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734023641; c=relaxed/simple; bh=S3gb/at7G0SagXWC0ALsWyDLFb6BiE6HAxOb2dit1mg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rLDYT5myMeyelE/6v5HT/ID8CJ2bBQjWWqWHCPHp1etqhFw1qvV27+VS+/xURdywrGNdqS0m/ZSz3F43xCnjRMygI8cxJTvVfVTJj77qNU8euSP2vc72J3U/TGRUm9GSbddsLjk+UUDnXmJVBqYxv8KcuQ4bOGCV861lSY8Nrxw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Lt6NSUN9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Lt6NSUN9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 559BBC4CED3; Thu, 12 Dec 2024 17:14:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734023641; bh=S3gb/at7G0SagXWC0ALsWyDLFb6BiE6HAxOb2dit1mg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Lt6NSUN93tX+91ygENePsyomLjpkKDYymSaBIuJX1UeEXnH34IjIpjB1qjYI0d8Xh QhgrRa/o0dWH+H30W9oQcqZzlxg+Y/aH6olM1pdUokpYUkLaHdI70+AgjtEDLxAKZ8 VwWciEObE5UE6Bz0Y3tqkjq3Q5EOjRPDFIeHZFu0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Lorenzo Stoakes , Catalin Marinas , Jann Horn , Vlastimil Babka , Andreas Larsson , "David S. Miller" , Helge Deller , "James E.J. Bottomley" , "Liam R. Howlett" , Linus Torvalds , Mark Brown , Peter Xu , Will Deacon , Andrew Morton Subject: [PATCH 5.10 034/459] mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling Date: Thu, 12 Dec 2024 15:56:12 +0100 Message-ID: <20241212144254.873218870@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241212144253.511169641@linuxfoundation.org> References: <20241212144253.511169641@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lorenzo Stoakes [ Upstream commit 5baf8b037debf4ec60108ccfeccb8636d1dbad81 ] Currently MTE is permitted in two circumstances (desiring to use MTE having been specified by the VM_MTE flag) - where MAP_ANONYMOUS is specified, as checked by arch_calc_vm_flag_bits() and actualised by setting the VM_MTE_ALLOWED flag, or if the file backing the mapping is shmem, in which case we set VM_MTE_ALLOWED in shmem_mmap() when the mmap hook is activated in mmap_region(). The function that checks that, if VM_MTE is set, VM_MTE_ALLOWED is also set is the arm64 implementation of arch_validate_flags(). Unfortunately, we intend to refactor mmap_region() to perform this check earlier, meaning that in the case of a shmem backing we will not have invoked shmem_mmap() yet, causing the mapping to fail spuriously. It is inappropriate to set this architecture-specific flag in general mm code anyway, so a sensible resolution of this issue is to instead move the check somewhere else. We resolve this by setting VM_MTE_ALLOWED much earlier in do_mmap(), via the arch_calc_vm_flag_bits() call. This is an appropriate place to do this as we already check for the MAP_ANONYMOUS case here, and the shmem file case is simply a variant of the same idea - we permit RAM-backed memory. This requires a modification to the arch_calc_vm_flag_bits() signature to pass in a pointer to the struct file associated with the mapping, however this is not too egregious as this is only used by two architectures anyway - arm64 and parisc. So this patch performs this adjustment and removes the unnecessary assignment of VM_MTE_ALLOWED in shmem_mmap(). [akpm@linux-foundation.org: fix whitespace, per Catalin] Link: https://lkml.kernel.org/r/ec251b20ba1964fb64cf1607d2ad80c47f3873df.1730224667.git.lorenzo.stoakes@oracle.com Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes Suggested-by: Catalin Marinas Reported-by: Jann Horn Reviewed-by: Catalin Marinas Reviewed-by: Vlastimil Babka Cc: Andreas Larsson Cc: David S. Miller Cc: Helge Deller Cc: James E.J. Bottomley Cc: Liam R. Howlett Cc: Linus Torvalds Cc: Mark Brown Cc: Peter Xu Cc: Will Deacon Cc: Signed-off-by: Andrew Morton Signed-off-by: Lorenzo Stoakes Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/mman.h | 10 +++++++--- include/linux/mman.h | 7 ++++--- mm/mmap.c | 2 +- mm/nommu.c | 2 +- mm/shmem.c | 3 --- 5 files changed, 13 insertions(+), 11 deletions(-) --- a/arch/arm64/include/asm/mman.h +++ b/arch/arm64/include/asm/mman.h @@ -3,6 +3,8 @@ #define __ASM_MMAN_H__ #include +#include +#include #include #include @@ -21,19 +23,21 @@ static inline unsigned long arch_calc_vm } #define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey) -static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags) +static inline unsigned long arch_calc_vm_flag_bits(struct file *file, + unsigned long flags) { /* * Only allow MTE on anonymous mappings as these are guaranteed to be * backed by tags-capable memory. The vm_flags may be overridden by a * filesystem supporting MTE (RAM-based). */ - if (system_supports_mte() && (flags & MAP_ANONYMOUS)) + if (system_supports_mte() && + ((flags & MAP_ANONYMOUS) || shmem_file(file))) return VM_MTE_ALLOWED; return 0; } -#define arch_calc_vm_flag_bits(flags) arch_calc_vm_flag_bits(flags) +#define arch_calc_vm_flag_bits(file, flags) arch_calc_vm_flag_bits(file, flags) static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags) { --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -2,6 +2,7 @@ #ifndef _LINUX_MMAN_H #define _LINUX_MMAN_H +#include #include #include @@ -87,7 +88,7 @@ static inline void vm_unacct_memory(long #endif #ifndef arch_calc_vm_flag_bits -#define arch_calc_vm_flag_bits(flags) 0 +#define arch_calc_vm_flag_bits(file, flags) 0 #endif #ifndef arch_vm_get_page_prot @@ -148,13 +149,13 @@ calc_vm_prot_bits(unsigned long prot, un * Combine the mmap "flags" argument into "vm_flags" used internally. */ static inline unsigned long -calc_vm_flag_bits(unsigned long flags) +calc_vm_flag_bits(struct file *file, unsigned long flags) { return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) | _calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) | _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) | _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) | - arch_calc_vm_flag_bits(flags); + arch_calc_vm_flag_bits(file, flags); } unsigned long vm_commit_limit(void); --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1468,7 +1468,7 @@ unsigned long do_mmap(struct file *file, * to. we assume access permissions have been handled by the open * of the memory object, so we don't do any here. */ - vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | + vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(file, flags) | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; if (flags & MAP_LOCKED) --- a/mm/nommu.c +++ b/mm/nommu.c @@ -919,7 +919,7 @@ static unsigned long determine_vm_flags( { unsigned long vm_flags; - vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags); + vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(file, flags); /* vm_flags |= mm->def_flags; */ if (!(capabilities & NOMMU_MAP_DIRECT)) { --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2267,9 +2267,6 @@ static int shmem_mmap(struct file *file, if (ret) return ret; - /* arm64 - allow memory tagging on RAM-based files */ - vma->vm_flags |= VM_MTE_ALLOWED; - file_accessed(file); vma->vm_ops = &shmem_vm_ops; if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&