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 65341226553; Thu, 12 Dec 2024 16:42:19 +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=1734021739; cv=none; b=tqkh1z9GtbpRY55BHFdTtpckcqCsQbR6hkhlV3RAqvPUF16rQCHubbibrL3+amezw5YdmjiT1ZfKCuXJdI24Xf4mhsw6Qa9BV9EXt3PatFCD4InKbCFY4uLwHEuJy7fZzqg2xjOwhnG9B4++uzFzVxXObryFcHCNBNPCU8d0ZTY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734021739; c=relaxed/simple; bh=V2YI9dT+H81ybLyVjKuhkodR9FLMotOVm9iY5ZvY3BU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ailQ4b6uZ8sc0rUySJmkD20lxpXfP8MFlq/8TOuUZHwZ8sjvBndYEZJHBb9wOONcGbI1Q0hijMKmvOnAZTIbIB+HAwqKJ+HfyRxNoOI3/V0RvGvn2z1479FPWFLA/kUK2Ilr/Q/v362pmseuKrgX3za19rc7R2bY6yEDsOJzwHU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=w1iE4yS6; 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="w1iE4yS6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40D76C4CECE; Thu, 12 Dec 2024 16:42:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734021739; bh=V2YI9dT+H81ybLyVjKuhkodR9FLMotOVm9iY5ZvY3BU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=w1iE4yS6YNaSugOWtsW3UKXC1WiStSaXYTChbSXwsiRGbDCFkA/63oIMaAR/7dO0y dHpG3dEce97gj7gttJsItdyql7MP73DAUlw3v9rG9TxyzA7/gPkqn96MN8m8PZeOPR IxvnUXVSmR/E8JGwo8EA2Zy5ESB1xfJobKDWvTlU= 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 5.15 048/565] mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling Date: Thu, 12 Dec 2024 15:54:03 +0100 Message-ID: <20241212144313.390585924@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241212144311.432886635@linuxfoundation.org> References: <20241212144311.432886635@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 5.15-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 @@ -90,7 +91,7 @@ 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 @@ -151,12 +152,12 @@ 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_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 @@ -1466,7 +1466,7 @@ 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 @@ -906,7 +906,7 @@ 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 @@ -2266,9 +2266,6 @@ 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) &&