Re: [PATCH 3/5] dma-buf: heaps: add Linaro secure dmabuf heap support

[Nicolas Dufresne]

Hi,

Le mardi 02 août 2022 à 11:58 +0200, Olivier Masse a écrit :
> add Linaro secure heap bindings: linaro,secure-heap

Just a curiosity, how is this specific to Linaro OPTEE OS ? Shouldn't it be "de-
linaro-ified" somehow ?

regards,
Nicolas

> use genalloc to allocate/free buffer from buffer pool.
> buffer pool info is from dts.
> use sg_table instore the allocated memory info, the length of sg_table is 1.
> implement secure_heap_buf_ops to implement buffer share in difference device:
> 1. Userspace passes this fd to all drivers it wants this buffer
> to share with: First the filedescriptor is converted to a &dma_buf using
> dma_buf_get(). Then the buffer is attached to the device using dma_buf_attach().
> 2. Once the buffer is attached to all devices userspace can initiate DMA
> access to the shared buffer. In the kernel this is done by calling dma_buf_map_attachment()
> 3. get sg_table with dma_buf_map_attachment in difference device.
> 
> Signed-off-by: Olivier Masse <olivier.masse@xxxxxxx>
> ---
>  drivers/dma-buf/heaps/Kconfig       |  21 +-
>  drivers/dma-buf/heaps/Makefile      |   1 +
>  drivers/dma-buf/heaps/secure_heap.c | 588 ++++++++++++++++++++++++++++
>  3 files changed, 606 insertions(+), 4 deletions(-)
>  create mode 100644 drivers/dma-buf/heaps/secure_heap.c
> 
> diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
> index 6a33193a7b3e..b2406932192e 100644
> --- a/drivers/dma-buf/heaps/Kconfig
> +++ b/drivers/dma-buf/heaps/Kconfig
> @@ -1,8 +1,12 @@
> -config DMABUF_HEAPS_DEFERRED_FREE
> -	tristate
> +menuconfig DMABUF_HEAPS_DEFERRED_FREE
> +	bool "DMA-BUF heaps deferred-free library"
> +	help
> +	  Choose this option to enable the DMA-BUF heaps deferred-free library.
>  
> -config DMABUF_HEAPS_PAGE_POOL
> -	tristate
> +menuconfig DMABUF_HEAPS_PAGE_POOL
> +	bool "DMA-BUF heaps page-pool library"
> +	help
> +	  Choose this option to enable the DMA-BUF heaps page-pool library.
>  
>  config DMABUF_HEAPS_SYSTEM
>  	bool "DMA-BUF System Heap"
> @@ -26,3 +30,12 @@ config DMABUF_HEAPS_DSP
>            Choose this option to enable the dsp dmabuf heap. The dsp heap
>            is allocated by gen allocater. it's allocated according the dts.
>            If in doubt, say Y.
> +
> +config DMABUF_HEAPS_SECURE
> +	tristate "DMA-BUF Secure Heap"
> +	depends on DMABUF_HEAPS && DMABUF_HEAPS_DEFERRED_FREE
> +	help
> +	  Choose this option to enable the secure dmabuf heap. The secure heap
> +	  pools are defined according to the DT. Heaps are allocated
> +	  in the pools using gen allocater.
> +	  If in doubt, say Y.
> diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile
> index e70722ea615e..08f6aa5919d1 100644
> --- a/drivers/dma-buf/heaps/Makefile
> +++ b/drivers/dma-buf/heaps/Makefile
> @@ -4,3 +4,4 @@ obj-$(CONFIG_DMABUF_HEAPS_PAGE_POOL)	+= page_pool.o
>  obj-$(CONFIG_DMABUF_HEAPS_SYSTEM)	+= system_heap.o
>  obj-$(CONFIG_DMABUF_HEAPS_CMA)		+= cma_heap.o
>  obj-$(CONFIG_DMABUF_HEAPS_DSP)          += dsp_heap.o
> +obj-$(CONFIG_DMABUF_HEAPS_SECURE)	+= secure_heap.o
> diff --git a/drivers/dma-buf/heaps/secure_heap.c b/drivers/dma-buf/heaps/secure_heap.c
> new file mode 100644
> index 000000000000..31aac5d050b4
> --- /dev/null
> +++ b/drivers/dma-buf/heaps/secure_heap.c
> @@ -0,0 +1,588 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * DMABUF secure heap exporter
> + *
> + * Copyright 2021 NXP.
> + */
> +
> +#include <linux/dma-buf.h>
> +#include <linux/dma-heap.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/err.h>
> +#include <linux/genalloc.h>
> +#include <linux/highmem.h>
> +#include <linux/mm.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_fdt.h>
> +#include <linux/of_reserved_mem.h>
> +#include <linux/scatterlist.h>
> +#include <linux/slab.h>
> +#include <linux/vmalloc.h>
> +
> +#include "deferred-free-helper.h"
> +#include "page_pool.h"
> +
> +#define MAX_SECURE_HEAP 2
> +#define MAX_HEAP_NAME_LEN 32
> +
> +struct secure_heap_buffer {
> +	struct dma_heap *heap;
> +	struct list_head attachments;
> +	struct mutex lock;
> +	unsigned long len;
> +	struct sg_table sg_table;
> +	int vmap_cnt;
> +	struct deferred_freelist_item deferred_free;
> +	void *vaddr;
> +	bool uncached;
> +};
> +
> +struct dma_heap_attachment {
> +	struct device *dev;
> +	struct sg_table *table;
> +	struct list_head list;
> +	bool no_map;
> +	bool mapped;
> +	bool uncached;
> +};
> +
> +struct secure_heap_info {
> +	struct gen_pool *pool;
> +
> +	bool no_map;
> +};
> +
> +struct rmem_secure {
> +	phys_addr_t base;
> +	phys_addr_t size;
> +
> +	char name[MAX_HEAP_NAME_LEN];
> +
> +	bool no_map;
> +};
> +
> +static struct rmem_secure secure_data[MAX_SECURE_HEAP] = {0};
> +static unsigned int secure_data_count;
> +
> +static struct sg_table *dup_sg_table(struct sg_table *table)
> +{
> +	struct sg_table *new_table;
> +	int ret, i;
> +	struct scatterlist *sg, *new_sg;
> +
> +	new_table = kzalloc(sizeof(*new_table), GFP_KERNEL);
> +	if (!new_table)
> +		return ERR_PTR(-ENOMEM);
> +
> +	ret = sg_alloc_table(new_table, table->orig_nents, GFP_KERNEL);
> +	if (ret) {
> +		kfree(new_table);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	new_sg = new_table->sgl;
> +	for_each_sgtable_sg(table, sg, i) {
> +		sg_set_page(new_sg, sg_page(sg), sg->length, sg->offset);
> +		new_sg->dma_address = sg->dma_address;
> +#ifdef CONFIG_NEED_SG_DMA_LENGTH
> +		new_sg->dma_length = sg->dma_length;
> +#endif
> +		new_sg = sg_next(new_sg);
> +	}
> +
> +	return new_table;
> +}
> +
> +static int secure_heap_attach(struct dma_buf *dmabuf,
> +			      struct dma_buf_attachment *attachment)
> +{
> +	struct secure_heap_buffer *buffer = dmabuf->priv;
> +	struct secure_heap_info *info = dma_heap_get_drvdata(buffer->heap);
> +	struct dma_heap_attachment *a;
> +	struct sg_table *table;
> +
> +	a = kzalloc(sizeof(*a), GFP_KERNEL);
> +	if (!a)
> +		return -ENOMEM;
> +
> +	table = dup_sg_table(&buffer->sg_table);
> +	if (IS_ERR(table)) {
> +		kfree(a);
> +		return -ENOMEM;
> +	}
> +
> +	a->table = table;
> +	a->dev = attachment->dev;
> +	INIT_LIST_HEAD(&a->list);
> +	a->no_map = info->no_map;
> +	a->mapped = false;
> +	a->uncached = buffer->uncached;
> +	attachment->priv = a;
> +
> +	mutex_lock(&buffer->lock);
> +	list_add(&a->list, &buffer->attachments);
> +	mutex_unlock(&buffer->lock);
> +
> +	return 0;
> +}
> +
> +static void secure_heap_detach(struct dma_buf *dmabuf,
> +			       struct dma_buf_attachment *attachment)
> +{
> +	struct secure_heap_buffer *buffer = dmabuf->priv;
> +	struct dma_heap_attachment *a = attachment->priv;
> +
> +	mutex_lock(&buffer->lock);
> +	list_del(&a->list);
> +	mutex_unlock(&buffer->lock);
> +
> +	sg_free_table(a->table);
> +	kfree(a->table);
> +	kfree(a);
> +}
> +
> +static struct sg_table *secure_heap_map_dma_buf(struct dma_buf_attachment *attachment,
> +						enum dma_data_direction direction)
> +{
> +	struct dma_heap_attachment *a = attachment->priv;
> +	struct sg_table *table = a->table;
> +	int attr = 0;
> +	int ret;
> +
> +	if (!a->no_map) {
> +		if (a->uncached)
> +			attr = DMA_ATTR_SKIP_CPU_SYNC;
> +
> +		ret = dma_map_sgtable(attachment->dev, table, direction, attr);
> +		if (ret)
> +			return ERR_PTR(ret);
> +
> +		a->mapped = true;
> +	}
> +
> +	return table;
> +}
> +
> +static void secure_heap_unmap_dma_buf(struct dma_buf_attachment *attachment,
> +				      struct sg_table *table,
> +				      enum dma_data_direction direction)
> +{
> +	struct dma_heap_attachment *a = attachment->priv;
> +	int attr = 0;
> +
> +	if (!a->no_map)	{
> +		if (a->uncached)
> +			attr = DMA_ATTR_SKIP_CPU_SYNC;
> +
> +		a->mapped = false;
> +		dma_unmap_sgtable(attachment->dev, table, direction, attr);
> +	}
> +}
> +
> +static int secure_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
> +						enum dma_data_direction direction)
> +{
> +	struct secure_heap_buffer *buffer = dmabuf->priv;
> +	struct dma_heap_attachment *a;
> +
> +	mutex_lock(&buffer->lock);
> +
> +	if (buffer->vmap_cnt)
> +		invalidate_kernel_vmap_range(buffer->vaddr, buffer->len);
> +
> +	if (!buffer->uncached) {
> +		list_for_each_entry(a, &buffer->attachments, list) {
> +			if (!a->mapped)
> +				continue;
> +			dma_sync_sgtable_for_cpu(a->dev, a->table, direction);
> +		}
> +	}
> +	mutex_unlock(&buffer->lock);
> +
> +	return 0;
> +}
> +
> +static int secure_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
> +					      enum dma_data_direction direction)
> +{
> +	struct secure_heap_buffer *buffer = dmabuf->priv;
> +	struct dma_heap_attachment *a;
> +
> +	mutex_lock(&buffer->lock);
> +
> +	if (buffer->vmap_cnt)
> +		flush_kernel_vmap_range(buffer->vaddr, buffer->len);
> +
> +	if (!buffer->uncached) {
> +		list_for_each_entry(a, &buffer->attachments, list) {
> +			if (!a->mapped)
> +				continue;
> +			dma_sync_sgtable_for_device(a->dev, a->table, direction);
> +		}
> +	}
> +	mutex_unlock(&buffer->lock);
> +
> +	return 0;
> +}
> +
> +static int secure_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
> +{
> +	struct secure_heap_buffer *buffer = dmabuf->priv;
> +	struct sg_table *table = &buffer->sg_table;
> +	unsigned long addr = vma->vm_start;
> +	struct sg_page_iter piter;
> +	int ret;
> +
> +	if (buffer->uncached)
> +		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
> +
> +	for_each_sgtable_page(table, &piter, vma->vm_pgoff) {
> +		struct page *page = sg_page_iter_page(&piter);
> +
> +		ret = remap_pfn_range(vma, addr, page_to_pfn(page), PAGE_SIZE,
> +				      vma->vm_page_prot);
> +		if (ret)
> +			return ret;
> +		addr += PAGE_SIZE;
> +	}
> +	return 0;
> +}
> +
> +static void *secure_heap_do_vmap(struct secure_heap_buffer *buffer)
> +{
> +	struct sg_table *table = &buffer->sg_table;
> +	int npages = PAGE_ALIGN(buffer->len) / PAGE_SIZE;
> +	struct page **pages = vmalloc(sizeof(struct page *) * npages);
> +	struct page **tmp = pages;
> +	struct sg_page_iter piter;
> +	pgprot_t pgprot = PAGE_KERNEL;
> +	void *vaddr;
> +
> +	if (!pages)
> +		return ERR_PTR(-ENOMEM);
> +
> +	if (buffer->uncached)
> +		pgprot = pgprot_writecombine(PAGE_KERNEL);
> +
> +	for_each_sgtable_page(table, &piter, 0) {
> +		WARN_ON(tmp - pages >= npages);
> +		*tmp++ = sg_page_iter_page(&piter);
> +	}
> +
> +	vaddr = vmap(pages, npages, VM_MAP, pgprot);
> +	vfree(pages);
> +
> +	if (!vaddr)
> +		return ERR_PTR(-ENOMEM);
> +
> +	return vaddr;
> +}
> +
> +static int secure_heap_vmap(struct dma_buf *dmabuf, struct dma_buf_map *map)
> +{
> +	struct secure_heap_buffer *buffer = dmabuf->priv;
> +	void *vaddr;
> +	int ret = 0;
> +
> +	mutex_lock(&buffer->lock);
> +	if (buffer->vmap_cnt) {
> +		buffer->vmap_cnt++;
> +		goto out;
> +	}
> +
> +	vaddr = secure_heap_do_vmap(buffer);
> +	if (IS_ERR(vaddr)) {
> +		ret = PTR_ERR(vaddr);
> +		goto out;
> +	}
> +
> +	buffer->vaddr = vaddr;
> +	buffer->vmap_cnt++;
> +	dma_buf_map_set_vaddr(map, buffer->vaddr);
> +out:
> +	mutex_unlock(&buffer->lock);
> +
> +	return ret;
> +}
> +
> +static void secure_heap_vunmap(struct dma_buf *dmabuf, struct dma_buf_map *map)
> +{
> +	struct secure_heap_buffer *buffer = dmabuf->priv;
> +
> +	mutex_lock(&buffer->lock);
> +	if (!--buffer->vmap_cnt) {
> +		vunmap(buffer->vaddr);
> +		buffer->vaddr = NULL;
> +	}
> +	mutex_unlock(&buffer->lock);
> +	dma_buf_map_clear(map);
> +}
> +
> +static void secure_heap_zero_buffer(struct secure_heap_buffer *buffer)
> +{
> +	struct sg_table *sgt = &buffer->sg_table;
> +	struct sg_page_iter piter;
> +	struct page *p;
> +	void *vaddr;
> +
> +	for_each_sgtable_page(sgt, &piter, 0) {
> +		p = sg_page_iter_page(&piter);
> +		vaddr = kmap_atomic(p);
> +		memset(vaddr, 0, PAGE_SIZE);
> +		kunmap_atomic(vaddr);
> +	}
> +}
> +
> +static void secure_heap_buf_free(struct deferred_freelist_item *item,
> +				 enum df_reason reason)
> +{
> +	struct secure_heap_buffer *buffer;
> +	struct secure_heap_info *info;
> +	struct sg_table *table;
> +	struct scatterlist *sg;
> +	int i;
> +
> +	buffer = container_of(item, struct secure_heap_buffer, deferred_free);
> +	info = dma_heap_get_drvdata(buffer->heap);
> +
> +	if (!info->no_map) {
> +		// Zero the buffer pages before adding back to the pool
> +		if (reason == DF_NORMAL)
> +			secure_heap_zero_buffer(buffer);
> +	}
> +
> +	table = &buffer->sg_table;
> +	for_each_sg(table->sgl, sg, table->nents, i)
> +		gen_pool_free(info->pool, sg_dma_address(sg), sg_dma_len(sg));
> +
> +	sg_free_table(table);
> +	kfree(buffer);
> +}
> +
> +static void secure_heap_dma_buf_release(struct dma_buf *dmabuf)
> +{
> +	struct secure_heap_buffer *buffer = dmabuf->priv;
> +	int npages = PAGE_ALIGN(buffer->len) / PAGE_SIZE;
> +
> +	deferred_free(&buffer->deferred_free, secure_heap_buf_free, npages);
> +}
> +
> +static const struct dma_buf_ops secure_heap_buf_ops = {
> +	.attach = secure_heap_attach,
> +	.detach = secure_heap_detach,
> +	.map_dma_buf = secure_heap_map_dma_buf,
> +	.unmap_dma_buf = secure_heap_unmap_dma_buf,
> +	.begin_cpu_access = secure_heap_dma_buf_begin_cpu_access,
> +	.end_cpu_access = secure_heap_dma_buf_end_cpu_access,
> +	.mmap = secure_heap_mmap,
> +	.vmap = secure_heap_vmap,
> +	.vunmap = secure_heap_vunmap,
> +	.release = secure_heap_dma_buf_release,
> +};
> +
> +static struct dma_buf *secure_heap_do_allocate(struct dma_heap *heap,
> +					       unsigned long len,
> +					       unsigned long fd_flags,
> +					       unsigned long heap_flags,
> +					       bool uncached)
> +{
> +	struct secure_heap_buffer *buffer;
> +	struct secure_heap_info *info = dma_heap_get_drvdata(heap);
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +	unsigned long size = roundup(len, PAGE_SIZE);
> +	struct dma_buf *dmabuf;
> +	struct sg_table *table;
> +	int ret = -ENOMEM;
> +	unsigned long phy_addr;
> +
> +	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
> +	if (!buffer)
> +		return ERR_PTR(-ENOMEM);
> +
> +	INIT_LIST_HEAD(&buffer->attachments);
> +	mutex_init(&buffer->lock);
> +	buffer->heap = heap;
> +	buffer->len = size;
> +	buffer->uncached = uncached;
> +
> +	phy_addr = gen_pool_alloc(info->pool, size);
> +	if (!phy_addr)
> +		goto free_buffer;
> +
> +	table = &buffer->sg_table;
> +	if (sg_alloc_table(table, 1, GFP_KERNEL))
> +		goto free_pool;
> +
> +	sg_set_page(table->sgl,	phys_to_page(phy_addr),	size, 0);
> +	sg_dma_address(table->sgl) = phy_addr;
> +	sg_dma_len(table->sgl) = size;
> +
> +	/* create the dmabuf */
> +	exp_info.exp_name = dma_heap_get_name(heap);
> +	exp_info.ops = &secure_heap_buf_ops;
> +	exp_info.size = buffer->len;
> +	exp_info.flags = fd_flags;
> +	exp_info.priv = buffer;
> +	dmabuf = dma_buf_export(&exp_info);
> +	if (IS_ERR(dmabuf)) {
> +		ret = PTR_ERR(dmabuf);
> +		goto free_pages;
> +	}
> +
> +	return dmabuf;
> +
> +free_pages:
> +	sg_free_table(table);
> +
> +free_pool:
> +	gen_pool_free(info->pool, phy_addr, size);
> +
> +free_buffer:
> +	mutex_destroy(&buffer->lock);
> +	kfree(buffer);
> +
> +	return ERR_PTR(ret);
> +}
> +
> +static struct dma_buf *secure_heap_allocate(struct dma_heap *heap,
> +					    unsigned long len,
> +					    unsigned long fd_flags,
> +					    unsigned long heap_flags)
> +{
> +	// use uncache buffer here by default
> +	return secure_heap_do_allocate(heap, len, fd_flags, heap_flags, true);
> +	// use cache buffer
> +	// return secure_heap_do_allocate(heap, len, fd_flags, heap_flags, false);
> +}
> +
> +static const struct dma_heap_ops secure_heap_ops = {
> +	.allocate = secure_heap_allocate,
> +};
> +
> +static int secure_heap_add(struct rmem_secure *rmem)
> +{
> +	struct dma_heap *secure_heap;
> +	struct dma_heap_export_info exp_info;
> +	struct secure_heap_info *info = NULL;
> +	struct gen_pool *pool = NULL;
> +	int ret = -EINVAL;
> +
> +	if (rmem->base == 0 || rmem->size == 0) {
> +		pr_err("secure_data base or size is not correct\n");
> +		goto error;
> +	}
> +
> +	info = kzalloc(sizeof(*info), GFP_KERNEL);
> +	if (!info) {
> +		pr_err("dmabuf info allocation failed\n");
> +		ret = -ENOMEM;
> +		goto error;
> +	}
> +
> +	pool = gen_pool_create(PAGE_SHIFT, -1);
> +	if (!pool) {
> +		pr_err("can't create gen pool\n");
> +		ret = -ENOMEM;
> +		goto error;
> +	}
> +
> +	if (gen_pool_add(pool, rmem->base, rmem->size, -1) < 0) {
> +		pr_err("failed to add memory into pool\n");
> +		ret = -ENOMEM;
> +		goto error;
> +	}
> +
> +	info->pool = pool;
> +	info->no_map = rmem->no_map;
> +
> +	exp_info.name = rmem->name;
> +	exp_info.ops = &secure_heap_ops;
> +	exp_info.priv = info;
> +
> +	secure_heap = dma_heap_add(&exp_info);
> +	if (IS_ERR(secure_heap)) {
> +		pr_err("dmabuf secure heap allocation failed\n");
> +		ret = PTR_ERR(secure_heap);
> +		goto error;
> +	}
> +
> +	return 0;
> +
> +error:
> +	kfree(info);
> +	if (pool)
> +		gen_pool_destroy(pool);
> +
> +	return ret;
> +}
> +
> +static int secure_heap_create(void)
> +{
> +	unsigned int i;
> +	int ret;
> +
> +	for (i = 0; i < secure_data_count; i++) {
> +		ret = secure_heap_add(&secure_data[i]);
> +		if (ret)
> +			return ret;
> +	}
> +	return 0;
> +}
> +
> +static int rmem_secure_heap_device_init(struct reserved_mem *rmem,
> +					 struct device *dev)
> +{
> +	dev_set_drvdata(dev, rmem);
> +	return 0;
> +}
> +
> +static void rmem_secure_heap_device_release(struct reserved_mem *rmem,
> +					 struct device *dev)
> +{
> +	dev_set_drvdata(dev, NULL);
> +}
> +
> +static const struct reserved_mem_ops rmem_dma_ops = {
> +	.device_init    = rmem_secure_heap_device_init,
> +	.device_release = rmem_secure_heap_device_release,
> +};
> +
> +static int __init rmem_secure_heap_setup(struct reserved_mem *rmem)
> +{
> +	if (secure_data_count < MAX_SECURE_HEAP) {
> +		int name_len = 0;
> +		char *s = rmem->name;
> +
> +		secure_data[secure_data_count].base = rmem->base;
> +		secure_data[secure_data_count].size = rmem->size;
> +		secure_data[secure_data_count].no_map =
> +			(of_get_flat_dt_prop(rmem->fdt_node, "no-map", NULL) != NULL);
> +
> +		while (name_len < MAX_HEAP_NAME_LEN) {
> +			if ((*s == '@') || (*s == '\0'))
> +				break;
> +			name_len++;
> +			s++;
> +		}
> +		if (name_len == MAX_HEAP_NAME_LEN)
> +			name_len--;
> +
> +		strncpy(secure_data[secure_data_count].name, rmem->name, name_len);
> +
> +		rmem->ops = &rmem_dma_ops;
> +		pr_info("Reserved memory: DMA buf secure pool %s at %pa, size %ld MiB\n",
> +			secure_data[secure_data_count].name,
> +			&rmem->base, (unsigned long)rmem->size / SZ_1M);
> +
> +		secure_data_count++;
> +		return 0;
> +	}
> +	WARN_ONCE(1, "Cannot handle more than %u secure heaps\n", MAX_SECURE_HEAP);
> +	return -EINVAL;
> +}
> +
> +RESERVEDMEM_OF_DECLARE(secure_heap, "linaro,secure-heap", rmem_secure_heap_setup);
> +
> +module_init(secure_heap_create);
> +MODULE_LICENSE("GPL v2");