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Subject[PATCH v13 18/20] tee/optee, arm64: untag user pointers in check_mem_type
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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.

check_mem_type() uses provided user pointers for vma lookups (via
__check_mem_type()), which can only by done with untagged pointers.

Untag user pointers in this function.

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

diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
index a5afbe6dee68..e3be20264092 100644
--- a/drivers/tee/optee/call.c
+++ b/drivers/tee/optee/call.c
@@ -563,6 +563,7 @@ static int check_mem_type(unsigned long start, size_t num_pages)
int rc;

down_read(&mm->mmap_sem);
+ start = untagged_addr(start);
rc = __check_mem_type(find_vma(mm, start),
start + num_pages * PAGE_SIZE);
up_read(&mm->mmap_sem);
--
2.21.0.225.g810b269d1ac-goog
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