[RFC 2/7] tee: enable support to register kernel memory

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 2/7] tee: enable support to register kernel memory
Date: Thu, 13 Jun 2019 10:42:28 +0000	[thread overview]
Message-ID: <1560421833-27414-3-git-send-email-sumit.garg@linaro.org> (raw)
In-Reply-To: <1560421833-27414-1-git-send-email-sumit.garg@linaro.org>

Enable support to register kernel memory reference with TEE. This change
will allow TEE bus drivers to register memory references.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
---
 drivers/tee/tee_shm.c   | 16 ++++++++++++++--
 include/linux/tee_drv.h |  1 +
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index 2da026f..5c69b89 100644
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -9,6 +9,7 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/tee_drv.h>
+#include <linux/uio.h>
 #include "tee_private.h"
 
 static void tee_shm_release(struct tee_shm *shm)
@@ -224,13 +225,14 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
 {
 	struct tee_device *teedev = ctx->teedev;
 	const u32 req_flags = TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED;
+	const u32 req_ker_flags = TEE_SHM_DMA_BUF | TEE_SHM_KERNEL_MAPPED;
 	struct tee_shm *shm;
 	void *ret;
 	int rc;
 	int num_pages;
 	unsigned long start;
 
-	if (flags != req_flags)
+	if (flags != req_flags && flags != req_ker_flags)
 		return ERR_PTR(-ENOTSUPP);
 
 	if (!tee_device_get(teedev))
@@ -264,7 +266,17 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
 		goto err;
 	}
 
-	rc = get_user_pages_fast(start, num_pages, FOLL_WRITE, shm->pages);
+	if (flags & TEE_SHM_USER_MAPPED) {
+		rc = get_user_pages_fast(start, num_pages, FOLL_WRITE,
+					 shm->pages);
+	} else {
+		const struct kvec kiov = {
+			.iov_base = (void *)start,
+			.iov_len = PAGE_SIZE
+		};
+
+		rc = get_kernel_pages(&kiov, num_pages, 0, shm->pages);
+	}
 	if (rc > 0)
 		shm->num_pages = rc;
 	if (rc != num_pages) {
diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
index 7a03f68..dedf8fa 100644
--- a/include/linux/tee_drv.h
+++ b/include/linux/tee_drv.h
@@ -26,6 +26,7 @@
 #define TEE_SHM_REGISTER	BIT(3)  /* Memory registered in secure world */
 #define TEE_SHM_USER_MAPPED	BIT(4)  /* Memory mapped in user space */
 #define TEE_SHM_POOL		BIT(5)  /* Memory allocated from pool */
+#define TEE_SHM_KERNEL_MAPPED	BIT(6)  /* Memory mapped in kernel space */
 
 struct device;
 struct tee_device;
-- 
2.7.4
