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Subject[PATCH 3/5] dma-buf: heaps: add Linaro secure dmabuf heap support
Date
add Linaro secure heap bindings: linaro,secure-heap
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@nxp.com>
---
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");
--
2.25.0
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