linux-kernel - [PATCH v5 1/2] tee: enable support to register kernel memory

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Date:   Thu, 26 Mar 2020 12:53:48 +0530
From:   Sumit Garg <sumit.garg@...aro.org>
To:     jens.wiklander@...aro.org
Cc:     tee-dev@...ts.linaro.org, linux-kernel@...r.kernel.org,
        stuart.yoder@....com, daniel.thompson@...aro.org,
        Sumit Garg <sumit.garg@...aro.org>
Subject: [PATCH v5 1/2] tee: enable support to register kernel memory

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@...aro.org>
---
 drivers/tee/tee_shm.c   | 28 +++++++++++++++++++++++++---
 include/linux/tee_drv.h |  1 +
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index 937ac5a..a6c75a4 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)
@@ -217,14 +218,15 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
 				 size_t length, u32 flags)
 {
 	struct tee_device *teedev = ctx->teedev;
-	const u32 req_flags = TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED;
+	const u32 req_user_flags = TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED;
+	const u32 req_kernel_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_user_flags && flags != req_kernel_flags)
 		return ERR_PTR(-ENOTSUPP);
 
 	if (!tee_device_get(teedev))
@@ -259,7 +261,27 @@ 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 {
+		struct kvec *kiov;
+		int i;
+
+		kiov = kcalloc(num_pages, sizeof(*kiov), GFP_KERNEL);
+		if (!kiov) {
+			ret = ERR_PTR(-ENOMEM);
+			goto err;
+		}
+
+		for (i = 0; i < num_pages; i++) {
+			kiov[i].iov_base = (void *)(start + i * PAGE_SIZE);
+			kiov[i].iov_len = PAGE_SIZE;
+		}
+
+		rc = get_kernel_pages(kiov, num_pages, 0, shm->pages);
+		kfree(kiov);
+	}
 	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