[PATCH 11/35] mm: Define VM_SHADOW_STACK for arm64 when we support GCS
From: Mark Brown <broonie@kernel.org>
Date: 2023-07-16 21:55:16
Also in:
kvmarm, linux-arch, linux-doc, linux-fsdevel, linux-kselftest, linux-mm, linux-riscv, lkml
Subsystem:
documentation, filesystems (vfs and infrastructure), memory management - core, memory mapping, proc filesystem, the rest · Maintainers:
Jonathan Corbet, Alexander Viro, Christian Brauner, Andrew Morton, David Hildenbrand, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds
Use VM_HIGH_ARCH_5 for guarded control stack pages. Signed-off-by: Mark Brown <broonie@kernel.org> --- Documentation/filesystems/proc.rst | 2 +- fs/proc/task_mmu.c | 3 +++ include/linux/mm.h | 12 +++++++++++- 3 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 6ccb57089a06..086a0408a4d7 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst@@ -566,7 +566,7 @@ encoded manner. The codes are the following: mt arm64 MTE allocation tags are enabled um userfaultfd missing tracking uw userfaultfd wr-protect tracking - ss shadow stack page + ss shadow/guarded control stack page == ======================================= Note that there is no guarantee that every flag and associated mnemonic will
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index cfab855fe7e9..e8c50848bb16 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c@@ -711,6 +711,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ #ifdef CONFIG_X86_USER_SHADOW_STACK [ilog2(VM_SHADOW_STACK)] = "ss", +#endif +#ifdef CONFIG_ARM64_GCS + [ilog2(VM_SHADOW_STACK)] = "ss", #endif }; size_t i;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index bf16edf2fcd9..f526032c4dc6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -372,7 +372,17 @@ extern unsigned int kobjsize(const void *objp); * having a PAGE_SIZE guard gap. */ # define VM_SHADOW_STACK VM_HIGH_ARCH_5 -#else +#endif + +#if defined(CONFIG_ARM64_GCS) +/* + * arm64's Guarded Control Stack implements similar functionality and + * has similar constraints to shadow stacks. + */ +# define VM_SHADOW_STACK VM_HIGH_ARCH_5 +#endif + +#ifndef VM_SHADOW_STACK # define VM_SHADOW_STACK VM_NONE #endif
--
2.30.2
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