tee: Remove call to get_kernel_pages()

The kernel pages used by shm_get_kernel_pages() are allocated using
GFP_KERNEL through the following call stack:

trusted_instantiate()
	trusted_payload_alloc() -> GFP_KERNEL
	<trusted key op>
		tee_shm_register_kernel_buf()
			register_shm_helper()
				shm_get_kernel_pages()

Where <trusted key op> is one of:

	trusted_key_unseal()
	trusted_key_get_random()
	trusted_key_seal()

Because the pages can't be from highmem get_kernel_pages() boils down to
a get_page() call.

Remove the get_kernel_pages() call and open code the get_page().

In case a highmem page does slip through warn on once for a kmap'ed
address.

Cc: Jens Wiklander <jens.wiklander@linaro.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index 527a6eabc03e19922f83d1a4fe598e8442c598b9..b1c6231defad7a5ebf939e44466717f7e5645f6e 100644 (file)
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -11,6 +11,7 @@
 #include <linux/tee_drv.h>
 #include <linux/uaccess.h>
 #include <linux/uio.h>
+#include <linux/highmem.h>
 #include "tee_private.h"
 
 static void shm_put_kernel_pages(struct page **pages, size_t page_count)
@@ -24,26 +25,20 @@ static void shm_put_kernel_pages(struct page **pages, size_t page_count)
 static int shm_get_kernel_pages(unsigned long start, size_t page_count,
                                struct page **pages)
 {
-       struct kvec *kiov;
+       struct page *page;
        size_t n;
-       int rc;
 
-       if (WARN_ON_ONCE(is_vmalloc_addr((void *)start)))
+       if (WARN_ON_ONCE(is_vmalloc_addr((void *)start) ||
+                        is_kmap_addr((void *)start)))
                return -EINVAL;
 
-       kiov = kcalloc(page_count, sizeof(*kiov), GFP_KERNEL);
-       if (!kiov)
-               return -ENOMEM;
-
+       page = virt_to_page(start);
        for (n = 0; n < page_count; n++) {
-               kiov[n].iov_base = (void *)(start + n * PAGE_SIZE);
-               kiov[n].iov_len = PAGE_SIZE;
+               pages[n] = page + n;
+               get_page(pages[n]);
        }
 
-       rc = get_kernel_pages(kiov, page_count, 0, pages);
-       kfree(kiov);
-
-       return rc;
+       return page_count;
 }
 
 static void release_registered_pages(struct tee_shm *shm)