shm.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
  4 */
  5
  6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  7
  8#include <linux/firmware/qcom/qcom_tzmem.h>
  9#include <linux/mm.h>
 10
 11#include "qcomtee.h"
 12
 13/**
 14 * define MAX_OUTBOUND_BUFFER_SIZE - Maximum size of outbound buffers.
 15 *
 16 * The size of outbound buffer depends on QTEE callback requests.
 17 */
 18#define MAX_OUTBOUND_BUFFER_SIZE SZ_4K
 19
 20/**
 21 * define MAX_INBOUND_BUFFER_SIZE - Maximum size of the inbound buffer.
 22 *
 23 * The size of the inbound buffer depends on the user's requests,
 24 * specifically the number of IB and OB arguments. If an invocation
 25 * requires a size larger than %MAX_INBOUND_BUFFER_SIZE, the user should
 26 * consider using another form of shared memory with QTEE.
 27 */
 28#define MAX_INBOUND_BUFFER_SIZE SZ_4M
 29
 30/**
 31 * qcomtee_msg_buffers_alloc() - Allocate inbound and outbound buffers.
 32 * @oic: context to use for the current invocation.
 33 * @u: array of arguments for the current invocation.
 34 *
 35 * It calculates the size of inbound and outbound buffers based on the
 36 * arguments in @u. It allocates the buffers from the teedev pool.
 37 *
 38 * Return: On success, returns 0. On error, returns < 0.
 39 */
 40int qcomtee_msg_buffers_alloc(struct qcomtee_object_invoke_ctx *oic,
 41			      struct qcomtee_arg *u)
 42{
 43	struct tee_context *ctx = oic->ctx;
 44	struct tee_shm *shm;
 45	size_t size;
 46	int i;
 47
 48	/* Start offset in a message for buffer arguments. */
 49	size = qcomtee_msg_buffer_args(struct qcomtee_msg_object_invoke,
 50				       qcomtee_args_len(u));
 51	if (size > MAX_INBOUND_BUFFER_SIZE)
 52		return -EINVAL;
 53
 54	/* Add size of IB arguments. */
 55	qcomtee_arg_for_each_input_buffer(i, u) {
 56		size = size_add(size, qcomtee_msg_offset_align(u[i].b.size));
 57		if (size > MAX_INBOUND_BUFFER_SIZE)
 58			return -EINVAL;
 59	}
 60
 61	/* Add size of OB arguments. */
 62	qcomtee_arg_for_each_output_buffer(i, u) {
 63		size = size_add(size, qcomtee_msg_offset_align(u[i].b.size));
 64		if (size > MAX_INBOUND_BUFFER_SIZE)
 65			return -EINVAL;
 66	}
 67
 68	shm = tee_shm_alloc_priv_buf(ctx, size);
 69	if (IS_ERR(shm))
 70		return PTR_ERR(shm);
 71
 72	/* Allocate inbound buffer. */
 73	oic->in_shm = shm;
 74	shm = tee_shm_alloc_priv_buf(ctx, MAX_OUTBOUND_BUFFER_SIZE);
 75	if (IS_ERR(shm)) {
 76		tee_shm_free(oic->in_shm);
 77
 78		return PTR_ERR(shm);
 79	}
 80	/* Allocate outbound buffer. */
 81	oic->out_shm = shm;
 82
 83	oic->in_msg.addr = tee_shm_get_va(oic->in_shm, 0);
 84	oic->in_msg.size = tee_shm_get_size(oic->in_shm);
 85	oic->out_msg.addr = tee_shm_get_va(oic->out_shm, 0);
 86	oic->out_msg.size = tee_shm_get_size(oic->out_shm);
 87	/* QTEE assume unused buffers are zeroed. */
 88	memzero_explicit(oic->in_msg.addr, oic->in_msg.size);
 89	memzero_explicit(oic->out_msg.addr, oic->out_msg.size);
 90
 91	return 0;
 92}
 93
 94void qcomtee_msg_buffers_free(struct qcomtee_object_invoke_ctx *oic)
 95{
 96	tee_shm_free(oic->in_shm);
 97	tee_shm_free(oic->out_shm);
 98}
 99
100/* Dynamic shared memory pool based on tee_dyn_shm_alloc_helper(). */
101
102static int qcomtee_shm_register(struct tee_context *ctx, struct tee_shm *shm,
103				struct page **pages, size_t num_pages,
104				unsigned long start)
105{
106	return qcom_tzmem_shm_bridge_create(shm->paddr, shm->size,
107					    &shm->sec_world_id);
108}
109
110static int qcomtee_shm_unregister(struct tee_context *ctx, struct tee_shm *shm)
111{
112	qcom_tzmem_shm_bridge_delete(shm->sec_world_id);
113
114	return 0;
115}
116
117static int pool_op_alloc(struct tee_shm_pool *pool, struct tee_shm *shm,
118			 size_t size, size_t align)
119{
120	return tee_dyn_shm_alloc_helper(shm, size, align, qcomtee_shm_register);
121}
122
123static void pool_op_free(struct tee_shm_pool *pool, struct tee_shm *shm)
124{
125	tee_dyn_shm_free_helper(shm, qcomtee_shm_unregister);
126}
127
128static void pool_op_destroy_pool(struct tee_shm_pool *pool)
129{
130	kfree(pool);
131}
132
133static const struct tee_shm_pool_ops pool_ops = {
134	.alloc = pool_op_alloc,
135	.free = pool_op_free,
136	.destroy_pool = pool_op_destroy_pool,
137};
138
139struct tee_shm_pool *qcomtee_shm_pool_alloc(void)
140{
141	struct tee_shm_pool *pool;
142
143	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
144	if (!pool)
145		return ERR_PTR(-ENOMEM);
146
147	pool->ops = &pool_ops;
148
149	return pool;
150}