From: Catalin Marinas <catalin.marinas@arm.com>
Date: Fri, 29 Nov 2019 12:45:08 +0000 (+0000)
Subject: mm: Allow arm64 mmap(PROT_MTE) on RAM-based files
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=51b0bff2f703f7ecfeb228eaa3d8f6090c18c9c1;p=linux.git

mm: Allow arm64 mmap(PROT_MTE) on RAM-based files

Since arm64 memory (allocation) tags can only be stored in RAM, mapping
files with PROT_MTE is not allowed by default. RAM-based files like
those in a tmpfs mount or memfd_create() can support memory tagging, so
update the vm_flags accordingly in shmem_mmap().

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/shmem.c b/mm/shmem.c
index 271548ca20f31..ec94f4c7851e4 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2267,6 +2267,9 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
 			vma->vm_flags &= ~(VM_MAYWRITE);
 	}
 
+	/* 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) &&