x86/arch_prctl/vdso: Add ARCH_MAP_VDSO_*

Add API to change vdso blob type with arch_prctl.
As this is usefull only by needs of CRIU, expose
this interface under CONFIG_CHECKPOINT_RESTORE.

Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: 0x7f454c46@gmail.com
Cc: oleg@redhat.com
Cc: linux-mm@kvack.org
Cc: gorcunov@openvz.org
Cc: xemul@virtuozzo.com
Link: http://lkml.kernel.org/r/20160905133308.28234-4-dsafonov@virtuozzo.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 8 insertions, 0 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index ca9d91b..6373ebd 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3063,6 +3063,14 @@ out:
 	return ERR_PTR(ret);
 }
 
+bool vma_is_special_mapping(const struct vm_area_struct *vma,
+	const struct vm_special_mapping *sm)
+{
+	return vma->vm_private_data == sm &&
+		(vma->vm_ops == &special_mapping_vmops ||
+		 vma->vm_ops == &legacy_special_mapping_vmops);
+}
+
 /*
  * Called with mm->mmap_sem held for writing.
  * Insert a new vma covering the given region, with the given flags.