[RFC 1/7] tee: optee: allow kernel pages to register as shm

From: Sumit Garg <sumit.garg@linaro.org>
To: keyrings@vger.kernel.org, linux-integrity@vger.kernel.org,
	linux-security-module@vger.kernel.org
Cc: jens.wiklander@linaro.org, corbet@lwn.net, dhowells@redhat.com,
	jejb@linux.ibm.com, jarkko.sakkinen@linux.intel.com,
	zohar@linux.ibm.com, jmorris@namei.org, serge@hallyn.com,
	ard.biesheuvel@linaro.org, daniel.thompson@linaro.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	tee-dev@lists.linaro.org, Sumit Garg <sumit.garg@linaro.org>
Subject: [RFC 1/7] tee: optee: allow kernel pages to register as shm
Date: Thu, 13 Jun 2019 10:42:27 +0000	[thread overview]
Message-ID: <1560421833-27414-2-git-send-email-sumit.garg@linaro.org> (raw)
In-Reply-To: <1560421833-27414-1-git-send-email-sumit.garg@linaro.org>

Kernel pages are marked as normal type memory only so allow kernel pages
to be registered as shared memory with OP-TEE.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
---
 drivers/tee/optee/call.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
index aa94270..bce45b1 100644
--- a/drivers/tee/optee/call.c
+++ b/drivers/tee/optee/call.c
@@ -553,6 +553,13 @@ static int check_mem_type(unsigned long start, size_t num_pages)
 	struct mm_struct *mm = current->mm;
 	int rc;
 
+	/*
+	 * Allow kernel address to register with OP-TEE as kernel
+	 * pages are configured as normal memory only.
+	 */
+	if (virt_addr_valid(start))
+		return 0;
+
 	down_read(&mm->mmap_sem);
 	rc = __check_mem_type(find_vma(mm, start),
 			      start + num_pages * PAGE_SIZE);
-- 
2.7.4
