VM_SHSTK indicates a shadow stack memory area.
The shadow stack is implemented only for the 64-bit kernel.

Signed-off-by: Yu-cheng Yu <yu-cheng...@intel.com>
---
 fs/proc/task_mmu.c | 3 +++
 include/linux/mm.h | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 01d4eb0e6bd1..dd8b0cd1ea36 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -661,6 +661,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct 
vm_area_struct *vma)
                [ilog2(VM_PKEY_BIT4)]   = "",
 #endif
 #endif /* CONFIG_ARCH_HAS_PKEYS */
+#ifdef CONFIG_X86_INTEL_SHADOW_STACK_USER
+               [ilog2(VM_SHSTK)]       = "ss"
+#endif
        };
        size_t i;
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0e8834ac32b7..398f1e1c35e5 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -287,11 +287,13 @@ extern unsigned int kobjsize(const void *objp);
 #define VM_HIGH_ARCH_BIT_2     34      /* bit only usable on 64-bit 
architectures */
 #define VM_HIGH_ARCH_BIT_3     35      /* bit only usable on 64-bit 
architectures */
 #define VM_HIGH_ARCH_BIT_4     36      /* bit only usable on 64-bit 
architectures */
+#define VM_HIGH_ARCH_BIT_5     37      /* bit only usable on 64-bit 
architectures */
 #define VM_HIGH_ARCH_0 BIT(VM_HIGH_ARCH_BIT_0)
 #define VM_HIGH_ARCH_1 BIT(VM_HIGH_ARCH_BIT_1)
 #define VM_HIGH_ARCH_2 BIT(VM_HIGH_ARCH_BIT_2)
 #define VM_HIGH_ARCH_3 BIT(VM_HIGH_ARCH_BIT_3)
 #define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4)
+#define VM_HIGH_ARCH_5 BIT(VM_HIGH_ARCH_BIT_5)
 #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */
 
 #ifdef CONFIG_ARCH_HAS_PKEYS
@@ -329,6 +331,12 @@ extern unsigned int kobjsize(const void *objp);
 # define VM_MPX                VM_NONE
 #endif
 
+#ifdef CONFIG_X86_INTEL_SHADOW_STACK_USER
+# define VM_SHSTK      VM_HIGH_ARCH_5
+#else
+# define VM_SHSTK      VM_NONE
+#endif
+
 #ifndef VM_GROWSUP
 # define VM_GROWSUP    VM_NONE
 #endif
-- 
2.17.1

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