[PATCH v15 06/17] mm: untag user pointers in do_pages_move

Andrey Konovalov
2019-05-06T16:31:28Z

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

do_pages_move() is used in the implementation of the move_pages syscall.

Untag user pointers in this function.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
mm/migrate.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/mm/migrate.c b/mm/migrate.c
index 663a5449367a..c014a07135f0 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1617,6 +1617,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
if (get_user(node, nodes + i))
goto out_flush;
addr = (unsigned long)p;
+ addr = untagged_addr(addr);

err = -ENODEV;
if (node < 0 || node >= MAX_NUMNODES)
--
2.21.0.1020.gf2820cf01a-goog