Commit 0249a75b authored by Ira Weiny's avatar Ira Weiny Committed by Jens Wiklander
Browse files

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: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarSumit Garg <sumit.garg@linaro.org>
Signed-off-by: default avatarJens Wiklander <jens.wiklander@linaro.org>
parent c8390039

drivers/tee/tee_shm.c

+8 −13
Original line number Diff line number Diff line
@@ -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)