mm: smaps: Report arm64 guarded pages in smaps

The arm64 Branch Target Identification support is activated by marking
executable pages as guarded pages.  Report pages mapped this way in
smaps to aid diagnostics.

Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Daniel Kiss <daniel.kiss@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 99ca040e3f900e399b59e2b5233fa9169ac61ccb..ed5465d0f4350e29fb3d2b47324563e4a418979e 100644 (file)
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -519,6 +519,7 @@ manner. The codes are the following:
     hg  - huge page advise flag
     nh  - no-huge page advise flag
     mg  - mergable advise flag
+    bt  - arm64 BTI guarded page
 
 Note that there is no guarantee that every flag and associated mnemonic will
 be present in all further kernel releases. Things get changed, the flags may

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 3ba9ae83bff5a54a98d831c9cee416e06fa41a08..1e3409c484d16cff89d60ff2e6e00841ce51d3fd 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -668,6 +668,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
                [ilog2(VM_ARCH_1)]      = "ar",
                [ilog2(VM_WIPEONFORK)]  = "wf",
                [ilog2(VM_DONTDUMP)]    = "dd",
+#ifdef CONFIG_ARM64_BTI
+               [ilog2(VM_ARM64_BTI)]   = "bt",
+#endif
 #ifdef CONFIG_MEM_SOFT_DIRTY
                [ilog2(VM_SOFTDIRTY)]   = "sd",
 #endif