[RFC v2 2/6] tee: enable support to register kernel memory

[Sumit Garg <sumit.garg@xxxxxxxxxx>]

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@xxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Reviewed-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
---
 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