qcom_tzmem.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Memory allocator for buffers shared with the TrustZone.
 *
 * Copyright (C) 2023-2024 Linaro Ltd.
 */

#include <linux/bug.h>
#include <linux/cleanup.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/firmware/qcom/qcom_tzmem.h>
#include <linux/genalloc.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/radix-tree.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/types.h>

#include "qcom_tzmem.h"

struct qcom_tzmem_area { … };

struct qcom_tzmem_pool { … };

struct qcom_tzmem_chunk { … };

static struct device *qcom_tzmem_dev;
static RADIX_TREE(qcom_tzmem_chunks, GFP_ATOMIC);
static DEFINE_SPINLOCK(qcom_tzmem_chunks_lock);

#if IS_ENABLED(CONFIG_QCOM_TZMEM_MODE_GENERIC)

static int qcom_tzmem_init(void)
{ … }

static int qcom_tzmem_init_area(struct qcom_tzmem_area *area)
{ … }

static void qcom_tzmem_cleanup_area(struct qcom_tzmem_area *area)
{ … }

#elif IS_ENABLED(CONFIG_QCOM_TZMEM_MODE_SHMBRIDGE)

#include <linux/firmware/qcom/qcom_scm.h>
#include <linux/of.h>

#define QCOM_SHM_BRIDGE_NUM_VM_SHIFT …

static bool qcom_tzmem_using_shm_bridge;

/* List of machines that are known to not support SHM bridge correctly. */
static const char *const qcom_tzmem_blacklist[] = {
	"qcom,sc8180x",
	"qcom,sdm845", /* reset in rmtfs memory assignment */
	"qcom,sm8150", /* reset in rmtfs memory assignment */
	NULL
};

static int qcom_tzmem_init(void)
{
	const char *const *platform;
	int ret;

	for (platform = qcom_tzmem_blacklist; *platform; platform++) {
		if (of_machine_is_compatible(*platform))
			goto notsupp;
	}

	ret = qcom_scm_shm_bridge_enable();
	if (ret == -EOPNOTSUPP)
		goto notsupp;

	if (!ret)
		qcom_tzmem_using_shm_bridge = true;

	return ret;

notsupp:
	dev_info(qcom_tzmem_dev, "SHM Bridge not supported\n");
	return 0;
}

static int qcom_tzmem_init_area(struct qcom_tzmem_area *area)
{
	u64 pfn_and_ns_perm, ipfn_and_s_perm, size_and_flags;
	int ret;

	if (!qcom_tzmem_using_shm_bridge)
		return 0;

	pfn_and_ns_perm = (u64)area->paddr | QCOM_SCM_PERM_RW;
	ipfn_and_s_perm = (u64)area->paddr | QCOM_SCM_PERM_RW;
	size_and_flags = area->size | (1 << QCOM_SHM_BRIDGE_NUM_VM_SHIFT);

	u64 *handle __free(kfree) = kzalloc(sizeof(*handle), GFP_KERNEL);
	if (!handle)
		return -ENOMEM;

	ret = qcom_scm_shm_bridge_create(qcom_tzmem_dev, pfn_and_ns_perm,
					 ipfn_and_s_perm, size_and_flags,
					 QCOM_SCM_VMID_HLOS, handle);
	if (ret)
		return ret;

	area->priv = no_free_ptr(handle);

	return 0;
}

static void qcom_tzmem_cleanup_area(struct qcom_tzmem_area *area)
{
	u64 *handle = area->priv;

	if (!qcom_tzmem_using_shm_bridge)
		return;

	qcom_scm_shm_bridge_delete(qcom_tzmem_dev, *handle);
	kfree(handle);
}

#endif /* CONFIG_QCOM_TZMEM_MODE_SHMBRIDGE */

static int qcom_tzmem_pool_add_memory(struct qcom_tzmem_pool *pool,
				      size_t size, gfp_t gfp)
{ … }

/**
 * qcom_tzmem_pool_new() - Create a new TZ memory pool.
 * @config: Pool configuration.
 *
 * Create a new pool of memory suitable for sharing with the TrustZone.
 *
 * Must not be used in atomic context.
 *
 * Return: New memory pool address or ERR_PTR() on error.
 */
struct qcom_tzmem_pool *
qcom_tzmem_pool_new(const struct qcom_tzmem_pool_config *config)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * qcom_tzmem_pool_free() - Destroy a TZ memory pool and free all resources.
 * @pool: Memory pool to free.
 *
 * Must not be called if any of the allocated chunks has not been freed.
 * Must not be used in atomic context.
 */
void qcom_tzmem_pool_free(struct qcom_tzmem_pool *pool)
{ … }
EXPORT_SYMBOL_GPL(…);

static void devm_qcom_tzmem_pool_free(void *data)
{ … }

/**
 * devm_qcom_tzmem_pool_new() - Managed variant of qcom_tzmem_pool_new().
 * @dev: Device managing this resource.
 * @config: Pool configuration.
 *
 * Must not be used in atomic context.
 *
 * Return: Address of the managed pool or ERR_PTR() on failure.
 */
struct qcom_tzmem_pool *
devm_qcom_tzmem_pool_new(struct device *dev,
			 const struct qcom_tzmem_pool_config *config)
{ … }
EXPORT_SYMBOL_GPL(…);

static bool qcom_tzmem_try_grow_pool(struct qcom_tzmem_pool *pool,
				     size_t requested, gfp_t gfp)
{ … }

/**
 * qcom_tzmem_alloc() - Allocate a memory chunk suitable for sharing with TZ.
 * @pool: TZ memory pool from which to allocate memory.
 * @size: Number of bytes to allocate.
 * @gfp: GFP flags.
 *
 * Can be used in any context.
 *
 * Return:
 * Address of the allocated buffer or NULL if no more memory can be allocated.
 * The buffer must be released using qcom_tzmem_free().
 */
void *qcom_tzmem_alloc(struct qcom_tzmem_pool *pool, size_t size, gfp_t gfp)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * qcom_tzmem_free() - Release a buffer allocated from a TZ memory pool.
 * @vaddr: Virtual address of the buffer.
 *
 * Can be used in any context.
 */
void qcom_tzmem_free(void *vaddr)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * qcom_tzmem_to_phys() - Map the virtual address of a TZ buffer to physical.
 * @vaddr: Virtual address of the buffer allocated from a TZ memory pool.
 *
 * Can be used in any context. The address must have been returned by a call
 * to qcom_tzmem_alloc().
 *
 * Returns: Physical address of the buffer.
 */
phys_addr_t qcom_tzmem_to_phys(void *vaddr)
{ … }
EXPORT_SYMBOL_GPL(…);

int qcom_tzmem_enable(struct device *dev)
{ … }
EXPORT_SYMBOL_GPL(…);

MODULE_DESCRIPTION(…) …;
MODULE_AUTHOR(…) …;
MODULE_LICENSE(…) …;
linux/drivers/firmware/qcom/qcom_tzmem.c
