Re: [PATCH v2 7/8] dma_buf: heaps: secure_heap: Add a new MediaTek CMA heap

[Jeffrey Kardatzke <jkardatzke@google.com>]

Most of the things in this patch should go in the MTK specific
implementation (except for the secure_heap_init changes). Especially
the RESERVEDMEM_OF_DECLARE.

On Sat, Nov 11, 2023 at 3:18 AM Yong Wu <yong.wu@mediatek.com> wrote:
>
> Create a new MediaTek CMA heap from the CMA reserved buffer.
>
> In this heap, When the first allocating buffer, use cma_alloc to prepare
> whole the CMA range, then send its range to TEE to protect and manage.
> For the later allocating, we just adds the cma_used_size_mtk.
>
> This CMA flow may be different with the normal CMA heap of next patch.
> So I named the variable with _mtk suffix like cma_page_mtk/
> cma_used_size_mtk. This is also to distinguish it from the cma_page of
> the buffer structure in the next patch.
>
> When SVP done, cma_release will release the buffer, then kernel may
> reuse it.
>
> Meanwhile, this patch adds a "heap_init" pointer, while allows some heap
> initialization operations. This case also checks if the CMA range is
> ready.
>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
>  drivers/dma-buf/heaps/secure_heap.c | 124 +++++++++++++++++++++++++++-
>  1 file changed, 122 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma-buf/heaps/secure_heap.c b/drivers/dma-buf/heaps/secure_heap.c
> index 25cc95442c56..f8b84fd16288 100644
> --- a/drivers/dma-buf/heaps/secure_heap.c
> +++ b/drivers/dma-buf/heaps/secure_heap.c
> @@ -4,11 +4,12 @@
>   *
>   * Copyright (C) 2023 MediaTek Inc.
>   */
> -
> +#include <linux/cma.h>
>  #include <linux/dma-buf.h>
>  #include <linux/dma-heap.h>
>  #include <linux/err.h>
>  #include <linux/module.h>
> +#include <linux/of_reserved_mem.h>
>  #include <linux/scatterlist.h>
>  #include <linux/slab.h>
>  #include <linux/tee_drv.h>
> @@ -25,6 +26,8 @@ enum secure_buffer_tee_cmd { /* PARAM NUM always is 4. */
>          * [in]  value[0].a: The buffer size.
>          *       value[0].b: alignment.
>          * [in]  value[1].a: enum secure_memory_type.
> +        * [in]  value[2].a: pa base in cma case.
> +        *       value[2].b: The buffer size in cma case.
>          * [out] value[3].a: The secure handle.
>          */
>         TZCMD_SECMEM_ZALLOC = 0,
> @@ -45,6 +48,13 @@ enum secure_memory_type {
>          * management is inside the TEE.
>          */
>         SECURE_MEMORY_TYPE_MTK_CM_TZ    = 1,
> +       /*
> +        * MediaTek dynamic chunk memory carved out from CMA.
> +        * In normal case, the CMA could be used in kernel; When SVP start, we will
> +        * allocate whole this CMA and pass whole the CMA PA and size into TEE to
> +        * protect it, then the detail memory management also is inside the TEE.
> +        */
> +       SECURE_MEMORY_TYPE_MTK_CM_CMA   = 2,
>  };
>
>  struct secure_buffer {
> @@ -70,6 +80,7 @@ struct secure_heap_prv_data {
>          */
>         const int                       tee_command_id_base;
>
> +       int     (*heap_init)(struct secure_heap *sec_heap);
>         int     (*memory_alloc)(struct secure_heap *sec_heap, struct secure_buffer *sec_buf);
>         void    (*memory_free)(struct secure_heap *sec_heap, struct secure_buffer *sec_buf);
>
> @@ -86,6 +97,13 @@ struct secure_heap {
>         u32                             tee_session;
>
>         const struct secure_heap_prv_data *data;
> +
> +       struct cma              *cma;
> +       struct page             *cma_page_mtk;
> +       unsigned long           cma_paddr;
> +       unsigned long           cma_size;
> +       unsigned long           cma_used_size_mtk;
> +       struct mutex            lock; /* lock for cma_used_size_mtk */
>  };
>
>  struct secure_heap_attachment {
> @@ -168,7 +186,10 @@ static int secure_heap_tee_secure_memory(struct secure_heap *sec_heap,
>         params[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
>         params[1].u.value.a = sec_heap->mem_type;
>         params[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
> -
> +       if (sec_heap->cma && sec_heap->mem_type == SECURE_MEMORY_TYPE_MTK_CM_CMA) {
> +               params[2].u.value.a = sec_heap->cma_paddr;
> +               params[2].u.value.b = sec_heap->cma_size;
> +       }
>         params[3].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
>         ret = secure_heap_tee_service_call(sec_heap->tee_ctx, sec_heap->tee_session,
>                                            data->tee_command_id_base + TZCMD_SECMEM_ZALLOC,
> @@ -197,6 +218,66 @@ static void secure_heap_tee_unsecure_memory(struct secure_heap *sec_heap,
>                        sec_heap->name, sec_buf->sec_handle, params[1].u.value.a);
>  }
>
> +static int mtk_secure_memory_cma_allocate(struct secure_heap *sec_heap,
> +                                         struct secure_buffer *sec_buf)
> +{
> +       /*
> +        * Allocate CMA only when allocating buffer for the first time, and just
> +        * increase cma_used_size_mtk at the other time.
> +        */
> +       mutex_lock(&sec_heap->lock);
> +       if (sec_heap->cma_used_size_mtk)
> +               goto add_size;
> +
> +       mutex_unlock(&sec_heap->lock);
> +       sec_heap->cma_page_mtk = cma_alloc(sec_heap->cma, sec_heap->cma_size >> PAGE_SHIFT,
> +                                          get_order(PAGE_SIZE), false);
> +       if (!sec_heap->cma_page_mtk)
> +               return -ENOMEM;
> +
> +       mutex_lock(&sec_heap->lock);
> +add_size:
> +       sec_heap->cma_used_size_mtk += sec_buf->size;
> +       mutex_unlock(&sec_heap->lock);
> +
> +       return 0;
> +}
> +
> +static void mtk_secure_memory_cma_free(struct secure_heap *sec_heap,
> +                                      struct secure_buffer *sec_buf)
> +{
> +       bool cma_is_empty;
> +
> +       mutex_lock(&sec_heap->lock);
> +       sec_heap->cma_used_size_mtk -= sec_buf->size;
> +       cma_is_empty = !sec_heap->cma_used_size_mtk;
> +       mutex_unlock(&sec_heap->lock);
> +
> +       if (cma_is_empty)
> +               cma_release(sec_heap->cma, sec_heap->cma_page_mtk,
> +                           sec_heap->cma_size >> PAGE_SHIFT);
> +}
> +
> +static int mtk_secure_heap_cma_init(struct secure_heap *sec_heap)
> +{
> +       if (!sec_heap->cma)
> +               return -EINVAL;
> +       mutex_init(&sec_heap->lock);
> +       return 0;
> +}
> +
> +/* Use CMA to prepare the buffer and the memory allocating is within the TEE. */
> +const struct secure_heap_prv_data mtk_sec_mem_data_cma = {
> +       .uuid                   = TZ_TA_MEM_UUID_MTK,
> +       .tee_impl_id            = TEE_IMPL_ID_OPTEE,
> +       .tee_command_id_base    = TEE_MEM_COMMAND_ID_BASE_MTK,
> +       .heap_init              = mtk_secure_heap_cma_init,
> +       .memory_alloc           = mtk_secure_memory_cma_allocate,
> +       .memory_free            = mtk_secure_memory_cma_free,
> +       .secure_the_memory      = secure_heap_tee_secure_memory,
> +       .unsecure_the_memory    = secure_heap_tee_unsecure_memory,
> +};
> +
>  /* The memory allocating is within the TEE. */
>  const struct secure_heap_prv_data mtk_sec_mem_data = {
>         .uuid                   = TZ_TA_MEM_UUID_MTK,
> @@ -420,20 +501,59 @@ static struct secure_heap secure_heaps[] = {
>                 .mem_type       = SECURE_MEMORY_TYPE_MTK_CM_TZ,
>                 .data           = &mtk_sec_mem_data,
>         },
> +       {
> +               .name           = "secure_mtk_cma",
> +               .mem_type       = SECURE_MEMORY_TYPE_MTK_CM_CMA,
> +               .data           = &mtk_sec_mem_data_cma,
> +       },
>  };
>
> +static int __init secure_cma_init(struct reserved_mem *rmem)
> +{
> +       struct secure_heap *sec_heap = secure_heaps;
> +       struct cma *sec_cma;
> +       int ret, i;
> +
> +       ret = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name,
> +                                   &sec_cma);
> +       if (ret) {
> +               pr_err("%s: %s set up CMA fail\n", __func__, rmem->name);
> +               return ret;
> +       }
> +
> +       for (i = 0; i < ARRAY_SIZE(secure_heaps); i++, sec_heap++) {
> +               if (sec_heap->mem_type != SECURE_MEMORY_TYPE_MTK_CM_CMA)
> +                       continue;
> +
> +               sec_heap->cma = sec_cma;
> +               sec_heap->cma_paddr = rmem->base;
> +               sec_heap->cma_size = rmem->size;
> +       }
> +       return 0;
> +}
> +
> +RESERVEDMEM_OF_DECLARE(secure_cma, "secure_cma_region", secure_cma_init);
> +
>  static int secure_heap_init(void)
>  {
>         struct secure_heap *sec_heap = secure_heaps;
>         struct dma_heap_export_info exp_info;
>         struct dma_heap *heap;
>         unsigned int i;
> +       int ret;
>
>         for (i = 0; i < ARRAY_SIZE(secure_heaps); i++, sec_heap++) {
>                 exp_info.name = sec_heap->name;
>                 exp_info.ops = &sec_heap_ops;
>                 exp_info.priv = (void *)sec_heap;
>
> +               if (sec_heap->data && sec_heap->data->heap_init) {
> +                       ret = sec_heap->data->heap_init(sec_heap);
> +                       if (ret) {
> +                               pr_err("sec_heap %s init fail %d.\n", sec_heap->name, ret);
> +                               continue;
> +                       }
> +               }
>                 heap = dma_heap_add(&exp_info);
>                 if (IS_ERR(heap))
>                         return PTR_ERR(heap);
> --
> 2.25.1
>