[PATCH v16 04/16] mm: untag user pointers in do_pages_move

Andrey Konovalov
2019-06-03T16:57:54Z

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.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
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 f2ecc2855a12..3930bb6fa656 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)
--
2.22.0.rc1.311.g5d7573a151-goog