Use VM_HIGH_ARCH_5 for guarded control stack pages.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@xxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
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 7c3a565ffbef..105312a0b33d 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -570,7 +570,7 @@ 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 1b56c1077507..6ef1137bcad8 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -706,6 +706,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
#ifdef CONFIG_ARCH_HAS_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 120abcfaf974..73211cfe7b31 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -353,7 +353,17 @@ extern unsigned int kobjsize(const void *objp);
* for more details on the guard size.
*/
# 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
--
2.39.2
