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

[Sumit Garg]

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.g...@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