drivers/tee/optee/shm_pool.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2015, Linaro Limited
 * Copyright (c) 2017, EPAM Systems
 */
#include <linux/device.h>
#include <linux/dma-buf.h>
#include <linux/genalloc.h>
#include <linux/slab.h>
#include <linux/tee_drv.h>
#include "optee_private.h"
#include "optee_smc.h"
#include "shm_pool.h"

static int pool_op_alloc(struct tee_shm_pool_mgr *poolm,
			 struct tee_shm *shm, size_t size)
{
	unsigned int order = get_order(size);
	struct page *page;

	page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
	if (!page)
		return -ENOMEM;

	shm->kaddr = page_address(page);
	shm->paddr = page_to_phys(page);
	shm->size = PAGE_SIZE << order;

	return 0;
}

static void pool_op_free(struct tee_shm_pool_mgr *poolm,
			 struct tee_shm *shm)
{
	free_pages((unsigned long)shm->kaddr, get_order(shm->size));
	shm->kaddr = NULL;
}

static void pool_op_destroy_poolmgr(struct tee_shm_pool_mgr *poolm)
{
	kfree(poolm);
}

static const struct tee_shm_pool_mgr_ops pool_ops = {
	.alloc = pool_op_alloc,
	.free = pool_op_free,
	.destroy_poolmgr = pool_op_destroy_poolmgr,
};

/**
 * optee_shm_pool_alloc_pages() - create page-based allocator pool
 *
 * This pool is used when OP-TEE supports dymanic SHM. In this case
 * command buffers and such are allocated from kernel's own memory.
 */
struct tee_shm_pool_mgr *optee_shm_pool_alloc_pages(void)
{
	struct tee_shm_pool_mgr *mgr = kzalloc(sizeof(*mgr), GFP_KERNEL);

	if (!mgr)
		return ERR_PTR(-ENOMEM);

	mgr->ops = &pool_ops;

	return mgr;
}