[PATCH v5 04/15] firmware: qcom: add a dedicated TrustZone buffer allocator

Bartosz Golaszewski
2023-10-17T09:28:06Z

We have several SCM calls that require passing buffers to the TrustZone
on top of the SMC core which allocates memory for calls that require
more than 4 arguments.

Currently every user does their own thing which leads to code
duplication. Many users call dma_alloc_coherent() for every call which
is terribly unperformant (speed- and size-wise).

Provide a set of library functions for creating and managing pool of
memory which is suitable for sharing with the TrustZone, that is:
page-aligned, contiguous and non-cachable as well as provides a way of
mapping of kernel virtual addresses to physical space.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Andrew Halaney <ahalaney@redhat.com>
Tested-by: Andrew Halaney <ahalaney@redhat.com> # sc8280xp-lenovo-thinkpad-x13s
---
drivers/firmware/qcom/Kconfig | 19 ++
drivers/firmware/qcom/Makefile | 1 +
drivers/firmware/qcom/qcom_tzmem.c | 302 +++++++++++++++++++++++
drivers/firmware/qcom/qcom_tzmem.h | 13 +
include/linux/firmware/qcom/qcom_tzmem.h | 28 +++
5 files changed, 363 insertions(+)
create mode 100644 drivers/firmware/qcom/qcom_tzmem.c
create mode 100644 drivers/firmware/qcom/qcom_tzmem.h
create mode 100644 include/linux/firmware/qcom/qcom_tzmem.h

diff --git a/drivers/firmware/qcom/Kconfig b/drivers/firmware/qcom/Kconfig
index 3f05d9854ddf..b80269a28224 100644
--- a/drivers/firmware/qcom/Kconfig
+++ b/drivers/firmware/qcom/Kconfig
@@ -9,6 +9,25 @@ menu "Qualcomm firmware drivers"
config QCOM_SCM
tristate

+config QCOM_TZMEM
+ tristate
+
+choice
+ prompt "TrustZone interface memory allocator mode"
+ default QCOM_TZMEM_MODE_DEFAULT
+ help
+ Selects the mode of the memory allocator providing memory buffers of
+ suitable format for sharing with the TrustZone. If in doubt, select
+ 'Default'.
+
+config QCOM_TZMEM_MODE_DEFAULT
+ bool "Default"
+ help
+ Use the default allocator mode. The memory is page-aligned, non-cachable
+ and contiguous.
+
+endchoice
+
config QCOM_SCM_DOWNLOAD_MODE_DEFAULT
bool "Qualcomm download mode enabled by default"
depends on QCOM_SCM
diff --git a/drivers/firmware/qcom/Makefile b/drivers/firmware/qcom/Makefile
index c9f12ee8224a..0be40a1abc13 100644
--- a/drivers/firmware/qcom/Makefile
+++ b/drivers/firmware/qcom/Makefile
@@ -5,5 +5,6 @@

obj-$(CONFIG_QCOM_SCM) += qcom-scm.o
qcom-scm-objs += qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
+obj-$(CONFIG_QCOM_TZMEM) += qcom_tzmem.o
obj-$(CONFIG_QCOM_QSEECOM) += qcom_qseecom.o
obj-$(CONFIG_QCOM_QSEECOM_UEFISECAPP) += qcom_qseecom_uefisecapp.o
diff --git a/drivers/firmware/qcom/qcom_tzmem.c b/drivers/firmware/qcom/qcom_tzmem.c
new file mode 100644
index 000000000000..68ca59c5598e
--- /dev/null
+++ b/drivers/firmware/qcom/qcom_tzmem.c
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Memory allocator for buffers shared with the TrustZone.
+ *
+ * Copyright (C) 2023 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/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_pool {
+ void *vbase;
+ phys_addr_t pbase;
+ size_t size;
+ struct gen_pool *pool;
+ void *priv;
+};
+
+struct qcom_tzmem_chunk {
+ phys_addr_t paddr;
+ size_t size;
+ struct qcom_tzmem_pool *owner;
+};
+
+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_DEFAULT)
+
+static int qcom_tzmem_init(void)
+{
+ return 0;
+}
+
+static int qcom_tzmem_init_pool(struct qcom_tzmem_pool *pool)
+{
+ return 0;
+}
+
+static void qcom_tzmem_cleanup_pool(struct qcom_tzmem_pool *pool)
+{
+
+}
+
+#endif /* CONFIG_QCOM_TZMEM_MODE_DEFAULT */
+
+/**
+ * qcom_tzmem_pool_new() - Create a new TZ memory pool.
+ * @size: Size of the new pool in bytes.
+ *
+ * Create a new pool of memory suitable for sharing with the TrustZone.
+ *
+ * Must not be used in atomic context.
+ *
+ * Returns:
+ * New memory pool address or ERR_PTR() on error.
+ */
+struct qcom_tzmem_pool *qcom_tzmem_pool_new(size_t size)
+{
+ struct qcom_tzmem_pool *pool;
+ int ret = -ENOMEM;
+
+ if (!size)
+ return ERR_PTR(-EINVAL);
+
+ size = PAGE_ALIGN(size);
+
+ pool = kzalloc(sizeof(*pool), GFP_KERNEL);
+ if (!pool)
+ return ERR_PTR(-ENOMEM);
+
+ pool->size = size;
+
+ pool->vbase = dma_alloc_coherent(qcom_tzmem_dev, size, &pool->pbase,
+ GFP_KERNEL);
+ if (!pool->vbase)
+ goto err_kfree_pool;
+
+ pool->pool = gen_pool_create(PAGE_SHIFT, -1);
+ if (!pool)
+ goto err_dma_free;
+
+ gen_pool_set_algo(pool->pool, gen_pool_best_fit, NULL);
+
+ ret = gen_pool_add_virt(pool->pool, (unsigned long)pool->vbase,
+ pool->pbase, size, -1);
+ if (ret)
+ goto err_destroy_genpool;
+
+ ret = qcom_tzmem_init_pool(pool);
+ if (ret)
+ goto err_destroy_genpool;
+
+ return pool;
+
+err_destroy_genpool:
+ gen_pool_destroy(pool->pool);
+err_dma_free:
+ dma_free_coherent(qcom_tzmem_dev, size, pool->vbase, pool->pbase);
+err_kfree_pool:
+ kfree(pool);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_pool_new);
+
+/**
+ * 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)
+{
+ struct qcom_tzmem_chunk *chunk;
+ struct radix_tree_iter iter;
+ bool non_empty = false;
+ void __rcu **slot;
+
+ if (!pool)
+ return;
+
+ qcom_tzmem_cleanup_pool(pool);
+
+ scoped_guard(spinlock_irqsave, &qcom_tzmem_chunks_lock) {
+ radix_tree_for_each_slot(slot, &qcom_tzmem_chunks, &iter, 0) {
+ chunk = radix_tree_deref_slot_protected(slot,
+ &qcom_tzmem_chunks_lock);
+
+ if (chunk->owner == pool)
+ non_empty = true;
+ }
+ }
+
+ WARN(non_empty, "Freeing TZ memory pool with memory still allocated");
+
+ gen_pool_destroy(pool->pool);
+ dma_free_coherent(qcom_tzmem_dev, pool->size, pool->vbase, pool->pbase);
+ kfree(pool);
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_pool_free);
+
+static void devm_qcom_tzmem_pool_free(void *data)
+{
+ struct qcom_tzmem_pool *pool = data;
+
+ qcom_tzmem_pool_free(pool);
+}
+
+/**
+ * devm_qcom_tzmem_pool_new() - Managed variant of qcom_tzmem_pool_new().
+ * @dev: Device managing this resource.
+ * @size: Size of the pool in bytes.
+ *
+ * Must not be used in atomic context.
+ *
+ * Returns:
+ * Address of the managed pool or ERR_PTR() on failure.
+ */
+struct qcom_tzmem_pool *
+devm_qcom_tzmem_pool_new(struct device *dev, size_t size)
+{
+ struct qcom_tzmem_pool *pool;
+ int ret;
+
+ pool = qcom_tzmem_pool_new(size);
+ if (IS_ERR(pool))
+ return pool;
+
+ ret = devm_add_action_or_reset(dev, devm_qcom_tzmem_pool_free, pool);
+ if (ret)
+ return ERR_PTR(ret);
+
+ return pool;
+}
+
+/**
+ * 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.
+ *
+ * Returns:
+ * 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)
+{
+ struct qcom_tzmem_chunk *chunk;
+ unsigned long vaddr;
+ int ret;
+
+ if (!size)
+ return NULL;
+
+ size = PAGE_ALIGN(size);
+
+ chunk = kzalloc(sizeof(*chunk), gfp);
+ if (!chunk)
+ return NULL;
+
+ vaddr = gen_pool_alloc(pool->pool, size);
+ if (!vaddr) {
+ kfree(chunk);
+ return NULL;
+ }
+
+ chunk->paddr = gen_pool_virt_to_phys(pool->pool, vaddr);
+ chunk->size = size;
+ chunk->owner = pool;
+
+ scoped_guard(spinlock_irqsave, &qcom_tzmem_chunks_lock) {
+ ret = radix_tree_insert(&qcom_tzmem_chunks, vaddr, chunk);
+ if (ret) {
+ gen_pool_free(pool->pool, vaddr, size);
+ kfree(chunk);
+ return NULL;
+ }
+ }
+
+ return (void *)vaddr;
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_alloc);
+
+/**
+ * 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)
+{
+ struct qcom_tzmem_chunk *chunk;
+
+ scoped_guard(spinlock_irqsave, &qcom_tzmem_chunks_lock)
+ chunk = radix_tree_delete_item(&qcom_tzmem_chunks,
+ (unsigned long)vaddr, NULL);
+
+ if (!chunk) {
+ WARN(1, "Virtual address %p not owned by TZ memory allocator",
+ vaddr);
+ return;
+ }
+
+ gen_pool_free(chunk->owner->pool, (unsigned long)vaddr, chunk->size);
+ kfree(chunk);
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_free);
+
+/**
+ * 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)
+{
+ struct qcom_tzmem_chunk *chunk;
+
+ guard(spinlock_irqsave)(&qcom_tzmem_chunks_lock);
+
+ chunk = radix_tree_lookup(&qcom_tzmem_chunks, (unsigned long)vaddr);
+ if (!chunk)
+ return 0;
+
+ return chunk->paddr;
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_to_phys);
+
+int qcom_tzmem_enable(struct device *dev)
+{
+ if (qcom_tzmem_dev)
+ return -EBUSY;
+
+ qcom_tzmem_dev = dev;
+
+ return qcom_tzmem_init();
+}
+EXPORT_SYMBOL_GPL(qcom_tzmem_enable);
+
+MODULE_DESCRIPTION("TrustZone memory allocator for Qualcomm firmware drivers");
+MODULE_AUTHOR("Bartosz Golaszewski <bartosz.golaszewski@linaro.org>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/firmware/qcom/qcom_tzmem.h b/drivers/firmware/qcom/qcom_tzmem.h
new file mode 100644
index 000000000000..f82f5dc5b7b1
--- /dev/null
+++ b/drivers/firmware/qcom/qcom_tzmem.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2023 Linaro Ltd.
+ */
+
+#ifndef __QCOM_TZMEM_PRIV_H
+#define __QCOM_TZMEM_PRIV_H
+
+struct device;
+
+int qcom_tzmem_enable(struct device *dev);
+
+#endif /* __QCOM_TZMEM_PRIV_H */
diff --git a/include/linux/firmware/qcom/qcom_tzmem.h b/include/linux/firmware/qcom/qcom_tzmem.h
new file mode 100644
index 000000000000..8e7fddab8cb4
--- /dev/null
+++ b/include/linux/firmware/qcom/qcom_tzmem.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2023 Linaro Ltd.
+ */
+
+#ifndef __QCOM_TZMEM_H
+#define __QCOM_TZMEM_H
+
+#include <linux/cleanup.h>
+#include <linux/gfp.h>
+#include <linux/types.h>
+
+struct device;
+struct qcom_tzmem_pool;
+
+struct qcom_tzmem_pool *qcom_tzmem_pool_new(size_t size);
+void qcom_tzmem_pool_free(struct qcom_tzmem_pool *pool);
+struct qcom_tzmem_pool *
+devm_qcom_tzmem_pool_new(struct device *dev, size_t size);
+
+void *qcom_tzmem_alloc(struct qcom_tzmem_pool *pool, size_t size, gfp_t gfp);
+void qcom_tzmem_free(void *ptr);
+
+DEFINE_FREE(qcom_tzmem, void *, if (_T) qcom_tzmem_free(_T));
+
+phys_addr_t qcom_tzmem_to_phys(void *ptr);
+
+#endif /* __QCOM_TZMEM */
--
2.39.2