path: root/drivers/tee/optee/ffa_abi.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2021, 2023 Linaro Limited
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/arm_ffa.h>
#include <linux/errno.h>
#include <linux/scatterlist.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/tee_drv.h>
#include <linux/types.h>
#include "optee_private.h"
#include "optee_ffa.h"
#include "optee_rpc_cmd.h"

/*
 * This file implement the FF-A ABI used when communicating with secure world
 * OP-TEE OS via FF-A.
 * This file is divided into the following sections:
 * 1. Maintain a hash table for lookup of a global FF-A memory handle
 * 2. Convert between struct tee_param and struct optee_msg_param
 * 3. Low level support functions to register shared memory in secure world
 * 4. Dynamic shared memory pool based on alloc_pages()
 * 5. Do a normal scheduled call into secure world
 * 6. Driver initialization.
 */

/*
 * 1. Maintain a hash table for lookup of a global FF-A memory handle
 *
 * FF-A assigns a global memory handle for each piece shared memory.
 * This handle is then used when communicating with secure world.
 *
 * Main functions are optee_shm_add_ffa_handle() and optee_shm_rem_ffa_handle()
 */
struct shm_rhash {
	struct tee_shm *shm;
	u64 global_id;
	struct rhash_head linkage;
};

static void rh_free_fn(void *ptr, void *arg)
{
	kfree(ptr);
}

static const struct rhashtable_params shm_rhash_params = {
	.head_offset = offsetof(struct shm_rhash, linkage),
	.key_len     = sizeof(u64),
	.key_offset  = offsetof(struct shm_rhash, global_id),
	.automatic_shrinking = true,
};

static struct tee_shm *optee_shm_from_ffa_handle(struct optee *optee,
						 u64 global_id)
{
	struct tee_shm *shm = NULL;
	struct shm_rhash *r;

	mutex_lock(&optee->ffa.mutex);
	r = rhashtable_lookup_fast(&optee->ffa.global_ids, &global_id,
				   shm_rhash_params);
	if (r)
		shm = r->shm;
	mutex_unlock(&optee->ffa.mutex);

	return shm;
}

static int optee_shm_add_ffa_handle(struct optee *optee, struct tee_shm *shm,
				    u64 global_id)
{
	struct shm_rhash *r;
	int rc;

	r = kmalloc(sizeof(*r), GFP_KERNEL);
	if (!r)
		return -ENOMEM;
	r->shm = shm;
	r->global_id = global_id;

	mutex_lock(&optee->ffa.mutex);
	rc = rhashtable_lookup_insert_fast(&optee->ffa.global_ids, &r->linkage,
					   shm_rhash_params);
	mutex_unlock(&optee->ffa.mutex);

	if (rc)
		kfree(r);

	return rc;
}

static int optee_shm_rem_ffa_handle(struct optee *optee, u64 global_id)
{
	struct shm_rhash *r;
	int rc = -ENOENT;

	mutex_lock(&optee->ffa.mutex);
	r = rhashtable_lookup_fast(&optee->ffa.global_ids, &global_id,
				   shm_rhash_params);
	if (r)
		rc = rhashtable_remove_fast(&optee->ffa.global_ids,
					    &r->linkage, shm_rhash_params);
	mutex_unlock(&optee->ffa.mutex);

	if (!rc)
		kfree(r);

	return rc;
}

/*
 * 2. Convert between struct tee_param and struct optee_msg_param
 *
 * optee_ffa_from_msg_param() and optee_ffa_to_msg_param() are the main
 * functions.
 */

static void from_msg_param_ffa_mem(struct optee *optee, struct tee_param *p,
				   u32 attr, const struct optee_msg_param *mp)
{
	struct tee_shm *shm = NULL;
	u64 offs_high = 0;
	u64 offs_low = 0;

	p->attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT +
		  attr - OPTEE_MSG_ATTR_TYPE_FMEM_INPUT;
	p->u.memref.size = mp->u.fmem.size;

	if (mp->u.fmem.global_id != OPTEE_MSG_FMEM_INVALID_GLOBAL_ID)
		shm = optee_shm_from_ffa_handle(optee, mp->u.fmem.global_id);
	p->u.memref.shm = shm;

	if (shm) {
		offs_low = mp->u.fmem.offs_low;
		offs_high = mp->u.fmem.offs_high;
	}
	p->u.memref.shm_offs = offs_low | offs_high << 32;
}

/**
 * optee_ffa_from_msg_param() - convert from OPTEE_MSG parameters to
 *				struct tee_param
 * @optee:	main service struct
 * @params:	subsystem internal parameter representation
 * @num_params:	number of elements in the parameter arrays
 * @msg_params:	OPTEE_MSG parameters
 *
 * Returns 0 on success or <0 on failure
 */
static int optee_ffa_from_msg_param(struct optee *optee,
				    struct tee_param *params, size_t num_params,
				    const struct optee_msg_param *msg_params)
{
	size_t n;

	for (n = 0; n < num_params; n++) {
		struct tee_param *p = params + n;
		const struct optee_msg_param *mp = msg_params + n;
		u32 attr = mp->attr & OPTEE_MSG_ATTR_TYPE_MASK;

		switch (attr) {
		case OPTEE_MSG_ATTR_TYPE_NONE:
			p->attr = TEE_IOCTL_PARAM_ATTR_TYPE_NONE;
			memset(&p->u, 0, sizeof(p->u));
			break;
		case OPTEE_MSG_ATTR_TYPE_VALUE_INPUT:
		case OPTEE_MSG_ATTR_TYPE_VALUE_OUTPUT:
		case OPTEE_MSG_ATTR_TYPE_VALUE_INOUT:
			optee_from_msg_param_value(p, attr, mp);
			break;
		case OPTEE_MSG_ATTR_TYPE_FMEM_INPUT:
		case OPTEE_MSG_ATTR_TYPE_FMEM_OUTPUT:
		case OPTEE_MSG_ATTR_TYPE_FMEM_INOUT:
			from_msg_param_ffa_mem(optee, p, attr, mp);
			break;
		default:
			return -EINVAL;
		}
	}

	return 0;
}

static int to_msg_param_ffa_mem(struct optee_msg_param *mp,
				const struct tee_param *p)
{
	struct tee_shm *shm = p