RE: [PATCH v4 2/3] mmc: block: register RPMB partition with the RPMB subsystem

[Avri Altman]

> +
> +#define RPMB_PROGRAM_KEY       0x1    /* Program RPMB Authentication
You expect the key to be already programmed - so you don't really need this operation?

> Key */
> +#define RPMB_GET_WRITE_COUNTER 0x2    /* Read RPMB write counter */
> +#define RPMB_WRITE_DATA        0x3    /* Write data to RPMB partition */
> +#define RPMB_READ_DATA         0x4    /* Read data from RPMB partition */
> +#define RPMB_RESULT_READ       0x5    /* Read result request  (Internal) */
> +
>  static DEFINE_MUTEX(block_mutex);
> 
>  /*
> @@ -163,6 +205,7 @@ struct mmc_rpmb_data {
>         int id;
>         unsigned int part_index;
>         struct mmc_blk_data *md;
> +       struct rpmb_dev *rdev;
>         struct list_head node;
>  };
> 
> @@ -2672,7 +2715,6 @@ static int mmc_rpmb_chrdev_open(struct inode
> *inode, struct file *filp)
> 
>         get_device(&rpmb->dev);
>         filp->private_data = rpmb;
> -       mmc_blk_get(rpmb->md->disk);
Maybe add a comment that this has moved to mmc_blk_alloc_rpmb_part?
For those who will look for it.

> 
>         return nonseekable_open(inode, filp);  } @@ -2682,7 +2724,6 @@ static
> int mmc_rpmb_chrdev_release(struct inode *inode, struct file *filp)
>         struct mmc_rpmb_data *rpmb = container_of(inode->i_cdev,
>                                                   struct mmc_rpmb_data, chrdev);
> 
> -       mmc_blk_put(rpmb->md);
Ditto.

>         put_device(&rpmb->dev);
> 
>         return 0;
> @@ -2703,10 +2744,157 @@ static void mmc_blk_rpmb_device_release(struct
> device *dev)  {
>         struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
> 
> +       rpmb_dev_unregister(rpmb->rdev);
> +       mmc_blk_put(rpmb->md);
>         ida_simple_remove(&mmc_rpmb_ida, rpmb->id);
>         kfree(rpmb);
>  }
> 
> +static void free_idata(struct mmc_blk_ioc_data **idata, unsigned int
> +cmd_count) {
> +       unsigned int n;
> +
> +       for (n = 0; n < cmd_count; n++)
> +               kfree(idata[n]);
> +       kfree(idata);
> +}
> +
> +static struct mmc_blk_ioc_data **alloc_idata(struct mmc_rpmb_data *rpmb,
> +                                            unsigned int cmd_count) {
> +       struct mmc_blk_ioc_data **idata;
> +       unsigned int n;
> +
> +       idata = kcalloc(cmd_count, sizeof(*idata), GFP_KERNEL);
> +       if (!idata)
> +               return NULL;
> +
> +       for (n = 0; n < cmd_count; n++) {
> +               idata[n] = kcalloc(1, sizeof(**idata), GFP_KERNEL);
> +               if (!idata[n]) {
> +                       free_idata(idata, n);
> +                       return NULL;
> +               }
> +               idata[n]->rpmb = rpmb;
> +       }
> +
> +       return idata;
> +}
> +
> +static void set_idata(struct mmc_blk_ioc_data *idata, u32 opcode,
> +                     int write_flag, u8 *buf, unsigned int buf_bytes) {
> +       idata->ic.opcode = opcode;
> +       idata->ic.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
> +       idata->ic.write_flag = write_flag;
> +       idata->ic.blksz = sizeof(struct rpmb_frame);
blksz = 512, so maybe add a compile-time check on sizeof(struct rpmb_frame)? 

> +       idata->ic.blocks = buf_bytes /  idata->ic.blksz;
> +       idata->buf = buf;
> +       idata->buf_bytes = buf_bytes;
> +}
> +
> +static int mmc_route_rpmb_frames(struct device *dev, u8 *req,
> +                                unsigned int req_len, u8 *resp,
> +                                unsigned int resp_len) {
> +       struct rpmb_frame *frm = (struct rpmb_frame *)req;
> +       struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
> +       struct mmc_blk_data *md = rpmb->md;
> +       struct mmc_blk_ioc_data **idata;
> +       unsigned int cmd_count;
> +       struct request *rq;
> +       u16 req_type;
> +       bool write;
> +       int ret;
> +
> +       if (IS_ERR(md->queue.card))
> +               return PTR_ERR(md->queue.card);
> +
> +       if (req_len < sizeof(*frm))
> +               return -EINVAL;
> +
> +       req_type = be16_to_cpu(frm->req_resp);
> +       switch (req_type) {
> +       case RPMB_PROGRAM_KEY:
> +               if (req_len != sizeof(struct rpmb_frame) ||
> +                   resp_len != sizeof(struct rpmb_frame))
> +                       return -EINVAL;
> +               write = true;
> +               break;
> +       case RPMB_GET_WRITE_COUNTER:
> +               if (req_len != sizeof(struct rpmb_frame) ||
> +                   resp_len != sizeof(struct rpmb_frame))
> +                       return -EINVAL;
> +               write = false;
> +               break;
> +       case RPMB_WRITE_DATA:
> +               if (req_len % sizeof(struct rpmb_frame) ||
> +                   resp_len != sizeof(struct rpmb_frame))
> +                       return -EINVAL;
> +               write = true;
> +               break;
> +       case RPMB_READ_DATA:
> +               if (req_len != sizeof(struct rpmb_frame) ||
> +                   resp_len % sizeof(struct rpmb_frame))
> +                       return -EINVAL;
> +               write = false;
> +               break;
> +       default:
> +               return -EINVAL;
> +       }
Looks like the above input validation section can be reduced to is RPMB_WRITE_DATA and default?

> +
> +       if (write)
> +               cmd_count = 3;
> +       else
> +               cmd_count = 2;
> +
> +       idata = alloc_idata(rpmb, cmd_count);
> +       if (!idata)
> +               return -ENOMEM;
> +
> +       if (write) {
> +               struct rpmb_frame *frm = (struct rpmb_frame *)resp;
> +
> +               /* Send write request frame(s) */
> +               set_idata(idata[0], MMC_WRITE_MULTIPLE_BLOCK,
> +                         1 | MMC_CMD23_ARG_REL_WR, req, req_len);
> +
> +               /* Send result request frame */
> +               memset(frm, 0, sizeof(*frm));
> +               frm->req_resp = cpu_to_be16(RPMB_RESULT_READ);
> +               set_idata(idata[1], MMC_WRITE_MULTIPLE_BLOCK, 1, resp,
> +                         resp_len);
> +
> +               /* Read response frame */
> +               set_idata(idata[2], MMC_READ_MULTIPLE_BLOCK, 0, resp,
> resp_len);
It is confusing to me that your response is holding 2 frame types:
The status frame and the response frame.


> +       } else {
> +               /* Send write request frame(s) */
> +               set_idata(idata[0], MMC_WRITE_MULTIPLE_BLOCK, 1, req,
> + req_len);
> +
> +               /* Read response frame */
> +               set_idata(idata[1], MMC_READ_MULTIPLE_BLOCK, 0, resp,
> resp_len);
> +       }
> +
> +       rq = blk_mq_alloc_request(md->queue.queue, REQ_OP_DRV_OUT, 0);
> +       if (IS_ERR(rq)) {
> +               ret = PTR_ERR(rq);
> +               goto out;
> +       }
> +
> +       req_to_mmc_queue_req(rq)->drv_op = MMC_DRV_OP_IOCTL_RPMB;
> +       req_to_mmc_queue_req(rq)->drv_op_result = -EIO;
> +       req_to_mmc_queue_req(rq)->drv_op_data = idata;
> +       req_to_mmc_queue_req(rq)->ioc_count = cmd_count;
Maybe have an additional struct mmc_queue_req *mq_rq = req_to_mmc_queue_req(rq);

> +       blk_execute_rq(rq, false);
> +       ret = req_to_mmc_queue_req(rq)->drv_op_result;
> +
> +       blk_mq_free_request(rq);
> +
> +out:
> +       free_idata(idata, cmd_count);
> +       return ret;
> +}
> +
>  static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
>                                    struct mmc_blk_data *md,
>                                    unsigned int part_index, @@ -2741,6 +2929,7 @@ static
> int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
>         rpmb->dev.release = mmc_blk_rpmb_device_release;
>         device_initialize(&rpmb->dev);
>         dev_set_drvdata(&rpmb->dev, rpmb);
> +       mmc_blk_get(md->disk);
>         rpmb->md = md;
> 
>         cdev_init(&rpmb->chrdev, &mmc_rpmb_fileops); @@ -3002,6 +3191,41
> @@ static void mmc_blk_remove_debugfs(struct mmc_card *card,
> 
>  #endif /* CONFIG_DEBUG_FS */
> 
> +static void mmc_blk_rpmb_add(struct mmc_card *card) {
> +       struct mmc_blk_data *md = dev_get_drvdata(&card->dev);
> +       struct mmc_rpmb_data *rpmb;
> +       struct rpmb_dev *rdev;
> +       unsigned int n;
> +       u32 cid[4];
> +       struct rpmb_descr descr = {
> +               .type = RPMB_TYPE_EMMC,
> +               .route_frames = mmc_route_rpmb_frames,
> +               .reliable_wr_count = card->ext_csd.raw_rpmb_size_mult,
> +               .capacity = card->ext_csd.rel_sectors,
The capacity is RPMB_SIZE_MULT and also limited to 16MB?
And you also need the region size you are writing to.
If I get your intention regarding reliable_wr_count, AFAIK, rpmb can be written either as a single, double, or 32 frames.
And this should be induced from card->ext_csd.rel_param, and not card->ext_csd.rel_sectors.

> +               .dev_id = (void *)cid,
> +               .dev_id_len = sizeof(cid),
> +       };
> +
> +       /*
> +        * Provice CID as an octet array. The CID needs to be interpreted
> +        * when used as input to derive the RPMB key since some fields
> +        * will change due to firmware updates.
> +        */
Not sure how the CID register is related to RPMB?
Is this something internal to TEE?

> +       for (n = 0; n < 4; n++)
> +               cid[n] = be32_to_cpu(card->raw_cid[n]);
> +
> +       list_for_each_entry(rpmb, &md->rpmbs, node) {
> +               rdev = rpmb_dev_register(&rpmb->dev, &descr);
> +               if (IS_ERR(rdev)) {
> +                       pr_warn("%s: could not register RPMB device\n",
> +                               dev_name(&rpmb->dev));
> +                       continue;
> +               }
> +               rpmb->rdev = rdev;
> +       }
> +}
> +

Thanks,
Avri