Re: [PATCH v5 2/3] mmc: block: register RPMB partition with the RPMB subsystem

On Mon, Apr 22, 2024 at 11:19:35AM +0200, Jens Wiklander wrote:

Register eMMC RPMB partition with the RPMB subsystem and provide an implementation for the RPMB access operations abstracting the actual multi step process.

Add a callback to extract the needed device information at registration to avoid accessing the struct mmc_card at a later stage as we're not holding a reference counter for this struct.

Taking the needed reference to md->disk in mmc_blk_alloc_rpmb_part() instead of in mmc_rpmb_chrdev_open(). This is needed by the route_frames() function pointer in struct rpmb_ops.

Signed-off-by: Tomas Winkler tomas.winkler@intel.com Signed-off-by: Alexander Usyskin alexander.usyskin@intel.com Signed-off-by: Jens Wiklander jens.wiklander@linaro.org

---

drivers/mmc/core/block.c | 241 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 239 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index 32d49100dff5..a7f126fbc605 100644 --- a/drivers/mmc/core/block.c +++ b/drivers/mmc/core/block.c @@ -33,6 +33,7 @@ #include <linux/cdev.h> #include <linux/mutex.h> #include <linux/scatterlist.h> +#include <linux/string.h> #include <linux/string_helpers.h> #include <linux/delay.h> #include <linux/capability.h> @@ -40,6 +41,7 @@ #include <linux/pm_runtime.h> #include <linux/idr.h> #include <linux/debugfs.h> +#include <linux/rpmb.h> #include <linux/mmc/ioctl.h> #include <linux/mmc/card.h> @@ -76,6 +78,48 @@ MODULE_ALIAS("mmc:block"); #define MMC_EXTRACT_INDEX_FROM_ARG(x) ((x & 0x00FF0000) >> 16) #define MMC_EXTRACT_VALUE_FROM_ARG(x) ((x & 0x0000FF00) >> 8) +/**

• • struct rpmb_frame - rpmb frame as defined by eMMC 5.1 (JESD84-B51)
• • @stuff : stuff bytes
• • @key_mac : The authentication key or the message authentication

• •             code (MAC) depending on the request/response type.
    

• •             The MAC will be delivered in the last (or the only)
    

• •             block of data.
    

• • @data : Data to be written or read by signed access.
• • @nonce : Random number generated by the host for the requests

• •             and copied to the response by the RPMB engine.
    

• • @write_counter: Counter value for the total amount of the successful

• •             authenticated data write requests made by the host.
    

• • @addr : Address of the data to be programmed to or read

• •             from the RPMB. Address is the serial number of
    

• •             the accessed block (half sector 256B).
    

• • @block_count : Number of blocks (half sectors, 256B) requested to be

• •             read/programmed.
    

• • @result : Includes information about the status of the write counter

• •             (valid, expired) and result of the access made to the RPMB.
    

• • @req_resp : Defines the type of request and response to/from the memory.
• • The stuff bytes and big-endian properties are modeled to fit to the spec.
• */

+struct rpmb_frame {

• u8 stuff[196];
• u8 key_mac[32];
• u8 data[256];
• u8 nonce[16];
• __be32 write_counter;
• __be16 addr;
• __be16 block_count;
• __be16 result;
• __be16 req_resp;

+} __packed;

+#define RPMB_PROGRAM_KEY 0x1 /* Program RPMB Authentication 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 +207,7 @@ 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 +2717,6 @@ 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);

return nonseekable_open(inode, filp); } @@ -2682,7 +2726,6 @@ 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); put_device(&rpmb->dev);

return 0; @@ -2703,10 +2746,165 @@ 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)
  

+{

• /*

• * The size of an RPMB frame must match what's expected by the
  

• * hardware.
  

• */
  

• BUILD_BUG_ON(sizeof(struct rpmb_frame) != 512);
• 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);
• idata->ic.blocks = buf_bytes / idata->ic.blksz;
• idata->buf = buf;

I tested the series on a i.MX8MM with a eMMC connected via the imx-sdhci controller. Reading from RPMB does not work. It ends in timeouts due to no response from the SDHCI controller.

If idata->buf is allocated here with kmalloc(buf_bytes, GFP_KERNEL) and the content of buf is copied to the new allocated area, transfers succeed.

Is it possible that idata->buf is not DMA capable? Any other ideas?

• 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;
• struct mmc_queue_req *mq_rq;
• 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;
  

• }
• 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);
  

• } 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;
  

• }
• mq_rq = req_to_mmc_queue_req(rq);
• mq_rq->drv_op = MMC_DRV_OP_IOCTL_RPMB;
• mq_rq->drv_op_result = -EIO;
• mq_rq->drv_op_data = idata;
• mq_rq->ioc_count = cmd_count;
• 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 +2939,7 @@ 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 +3201,42 @@ 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.enhanced_rpmb_supported ?
  

• 		     2 : 32,
  

• .capacity = card->ext_csd.raw_rpmb_size_mult,
  

• .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.
  

• */
  

• 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;
  

• }

+}

static int mmc_blk_probe(struct mmc_card *card) { struct mmc_blk_data *md; @@ -3047,6 +3282,8 @@ static int mmc_blk_probe(struct mmc_card *card) pm_runtime_enable(&card->dev); }

• mmc_blk_rpmb_add(card);
• return 0;

out: -- 2.34.1