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Date: Mon, 29 Apr 2024 12:35:43 +0200
From: Manuel Traut <manut@mecka.net>
To: Jens Wiklander <jens.wiklander@linaro.org>
Cc: linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org,
	op-tee@lists.trustedfirmware.org,
	Shyam Saini <shyamsaini@linux.microsoft.com>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Jerome Forissier <jerome.forissier@linaro.org>,
	Sumit Garg <sumit.garg@linaro.org>,
	Ilias Apalodimas <ilias.apalodimas@linaro.org>,
	Bart Van Assche <bvanassche@acm.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Ard Biesheuvel <ardb@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tomas Winkler <tomas.winkler@intel.com>,
	Alexander Usyskin <alexander.usyskin@intel.com>
Subject: Re: [PATCH v5 2/3] mmc: block: register RPMB partition with the RPMB
 subsystem
Message-ID: <Zi93_0aCq9mQ_6cD@mecka.net>
References: <20240422091936.3714381-1-jens.wiklander@linaro.org>
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 <ZioXkvnIw5V5MXBU@mecka.net>
 <CAHUa44Fojanryuc+ciJrVZUopRLcTt2teS_pC4BBjt1Wmy240A@mail.gmail.com>
 <Zi9rKzz8u8z7cIy0@mecka.net>
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On Mon, Apr 29, 2024 at 12:08:45PM +0200, Jens Wiklander wrote:
> On Mon, Apr 29, 2024 at 11:41 AM Manuel Traut <manut@mecka.net> wrote:
> >
> > On Fri, Apr 26, 2024 at 03:24:21PM +0200, Jens Wiklander wrote:
> > > On Thu, Apr 25, 2024 at 10:43 AM Manuel Traut <manut@mecka.net> wrote:
> > > >
> > > > 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?
> > >
> > > Thanks for testing. I don't know, the idata->buf is allocated using
> > > alloc_pages_exact(nr_pages * PAGE_SIZE, GFP_KERNEL | __GFP_ZERO); in
> > > optee_pool_op_alloc_helper().
> >
> > Is this really true for idata->buf or isnt the complete RPMB frame memory
> > allocated like this and therefore idata->buf not page aligned?
> 
> You're right.
> 
> >
> > For RPMB via tee-supplicant the idata->buf is allocated within memdup_user
> > and therefore page aligned.
> 
> Yes, that's a difference. Have you tested with page-aligned buffers to
> see if it helps?

Yes, this helps. I tested with the following patch, but probably it can also
be solved during frame allocation in optee?


commit b84a56c15abdcd07f4dacf0b7f482802f8ce752b
Author: Manuel Traut <manut@mecka.net>
Date:   Tue Apr 23 13:22:27 2024 +0200

    mmc: core: block: rpmb: Allocate page aligned memory
    
    "Random" position in optee shared memory cannot be used for blk
    IO on an eMMC with the i.MX8 SDHCI.
    
    This is for sure not the best possible solution, but works
    for the moment.

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 30da8fd03..f123a6c96 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2786,6 +2786,8 @@ static struct mmc_blk_ioc_data **alloc_idata(struct mmc_rpmb_data *rpmb,
 	return idata;
 }
 
+#define DYNALLOC 1
+
 static void set_idata(struct mmc_blk_ioc_data *idata, u32 opcode,
 		      int write_flag, u8 *buf, unsigned int buf_bytes)
 {
@@ -2800,10 +2802,23 @@ static void set_idata(struct mmc_blk_ioc_data *idata, u32 opcode,
 	idata->ic.write_flag = write_flag;
 	idata->ic.blksz = sizeof(struct rpmb_frame);
 	idata->ic.blocks = buf_bytes /  idata->ic.blksz;
+#ifdef DYNALLOC
+	idata->buf = kmalloc(buf_bytes, GFP_KERNEL);
+	memcpy(idata->buf, buf, buf_bytes);
+#else
 	idata->buf = buf;
+#endif
 	idata->buf_bytes = buf_bytes;
 }
 
+#ifdef DYNALLOC
+static void free_idata_buf(struct mmc_blk_ioc_data *idata, u8 *buf, unsigned int buf_bytes)
+{
+    memcpy(buf, idata->buf, buf_bytes);
+    kfree(idata->buf);
+}
+#endif
+
 static int mmc_route_rpmb_frames(struct device *dev, u8 *req,
 				 unsigned int req_len, u8 *resp,
 				 unsigned int resp_len)
@@ -2901,6 +2916,13 @@ static int mmc_route_rpmb_frames(struct device *dev, u8 *req,
 	blk_execute_rq(rq, false);
 	ret = req_to_mmc_queue_req(rq)->drv_op_result;
 
+#ifdef DYNALLOC
+	free_idata_buf(idata[0], req, req_len);
+	free_idata_buf(idata[1], resp, resp_len);
+	if (write)
+		free_idata_buf(idata[2], resp, resp_len);
+#endif
+
 	blk_mq_free_request(rq);
 
 out:

> > > Alternatively, it's from the memory
> > > range mapped using memremap() in optee_config_shm_memremap(), but
> > > that's only if you don't have "dynamic shared memory is enabled" in
> > > the boot log.
> >
> > "dynamic shared memory is enabled" is in the bootlog, ..
> 
> Great.

Thanks
Manuel