tee: simplify shm pool handling

Replaces the shared memory pool based on two pools with a single pool.
The alloc() function pointer in struct tee_shm_pool_ops gets another
parameter, align. This makes it possible to make less than page aligned
allocations from the optional reserved shared memory pool while still
making user space allocations page aligned. With in practice unchanged
behaviour using only a single pool for bookkeeping.

The allocation algorithm in the static OP-TEE shared memory pool is
changed from best-fit to first-fit since only the latter supports an
alignment parameter. The best-fit algorithm was previously the default
choice and not a conscious one.

The optee and amdtee drivers are updated as needed to work with this
changed pool handling.

This also removes OPTEE_SHM_NUM_PRIV_PAGES which becomes obsolete with
this change as the private pages can be mixed with the payload pages.

The OP-TEE driver changes minimum alignment for argument struct from 8
bytes to 512 bytes. A typical OP-TEE private shm allocation is 224 bytes
(argument struct with 6 parameters, needed for open session). So with an
alignment of 512 well waste a bit more than 50%. Before this we had a
single page reserved for this so worst case usage compared to that would
be 3 pages instead of 1 page. However, this worst case only occurs if
there is a high pressure from multiple threads on secure world. All in
all this should scale up and down better than fixed boundaries.

Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

1 files changed, 20 insertions, 40 deletions

diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
index a4393c8c38f3..ed641dc314bd 100644
--- a/include/linux/tee_drv.h
+++ b/include/linux/tee_drv.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
- * Copyright (c) 2015-2016 Linaro Limited
+ * Copyright (c) 2015-2022 Linaro Limited
  */
 
 #ifndef __TEE_DRV_H
@@ -221,62 +221,39 @@ struct tee_shm {
 };
 
 /**
- * struct tee_shm_pool_mgr - shared memory manager
+ * struct tee_shm_pool - shared memory pool
  * @ops:		operations
  * @private_data:	private data for the shared memory manager
  */
-struct tee_shm_pool_mgr {
-	const struct tee_shm_pool_mgr_ops *ops;
+struct tee_shm_pool {
+	const struct tee_shm_pool_ops *ops;
 	void *private_data;
 };
 
 /**
- * struct tee_shm_pool_mgr_ops - shared memory pool manager operations
+ * struct tee_shm_pool_ops - shared memory pool operations
  * @alloc:		called when allocating shared memory
  * @free:		called when freeing shared memory
- * @destroy_poolmgr:	called when destroying the pool manager
+ * @destroy_pool:	called when destroying the pool
  */
-struct tee_shm_pool_mgr_ops {
-	int (*alloc)(struct tee_shm_pool_mgr *poolmgr, struct tee_shm *shm,
-		     size_t size);
-	void (*free)(struct tee_shm_pool_mgr *poolmgr, struct tee_shm *shm);
-	void (*destroy_poolmgr)(struct tee_shm_pool_mgr *poolmgr);
+struct tee_shm_pool_ops {
+	int (*alloc)(struct tee_shm_pool *pool, struct tee_shm *shm,
+		     size_t size, size_t align);
+	void (*free)(struct tee_shm_pool *pool, struct tee_shm *shm);
+	void (*destroy_pool)(struct tee_shm_pool *pool);
 };
 
-/**
- * tee_shm_pool_alloc() - Create a shared memory pool from shm managers
- * @priv_mgr:	manager for driver private shared memory allocations
- * @dmabuf_mgr:	manager for dma-buf shared memory allocations
- *
- * Allocation with the flag TEE_SHM_DMA_BUF set will use the range supplied
- * in @dmabuf, others will use the range provided by @priv.
- *
- * @returns pointer to a 'struct tee_shm_pool' or an ERR_PTR on failure.
- */
-struct tee_shm_pool *tee_shm_pool_alloc(struct tee_shm_pool_mgr *priv_mgr,
-					struct tee_shm_pool_mgr *dmabuf_mgr);
-
 /*
- * tee_shm_pool_mgr_alloc_res_mem() - Create a shm manager for reserved
- * memory
+ * tee_shm_pool_alloc_res_mem() - Create a shm manager for reserved memory
  * @vaddr:	Virtual address of start of pool
  * @paddr:	Physical address of start of pool
  * @size:	Size in bytes of the pool
  *
- * @returns pointer to a 'struct tee_shm_pool_mgr' or an ERR_PTR on failure.
- */
-struct tee_shm_pool_mgr *tee_shm_pool_mgr_alloc_res_mem(unsigned long vaddr,
-							phys_addr_t paddr,
-							size_t size,
-							int min_alloc_order);
-
-/**
- * tee_shm_pool_mgr_destroy() - Free a shared memory manager
+ * @returns pointer to a 'struct tee_shm_pool' or an ERR_PTR on failure.
  */
-static inline void tee_shm_pool_mgr_destroy(struct tee_shm_pool_mgr *poolm)
-{
-	poolm->ops->destroy_poolmgr(poolm);
-}
+struct tee_shm_pool *tee_shm_pool_alloc_res_mem(unsigned long vaddr,
+						phys_addr_t paddr, size_t size,
+						int min_alloc_order);
 
 /**
  * tee_shm_pool_free() - Free a shared memory pool
@@ -285,7 +262,10 @@ static inline void tee_shm_pool_mgr_destroy(struct tee_shm_pool_mgr *poolm)
  * The must be no remaining shared memory allocated from this pool when
  * this function is called.
  */
-void tee_shm_pool_free(struct tee_shm_pool *pool);
+static inline void tee_shm_pool_free(struct tee_shm_pool *pool)
+{
+	pool->ops->destroy_pool(pool);
+}
 
 /**
  * tee_get_drvdata() - Return driver_data pointer