[PATCH v7 2/4] mmc: block: register RPMB partition with the RPMB subsystem

From: Jens Wiklander
Date: Mon May 27 2024 - 08:15:27 EST

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@xxxxxxxxx>
Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
Tested-by: Manuel Traut <manut@xxxxxxxxx>
---
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 90c51b12148e..713e09012954 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;
};

@@ -2674,7 +2719,6 @@ 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);
}
@@ -2684,7 +2728,6 @@ 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;
@@ -2705,10 +2748,165 @@ 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_free(&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;
+ 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,
@@ -2743,6 +2941,7 @@ 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);
@@ -3004,6 +3203,42 @@ 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;
@@ -3049,6 +3284,8 @@ 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