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Commit 162c3946 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt
Browse files

fsi: scom: Add mutex around FSI2PIB accesses 



Otherwise, multiple clients can open the driver and attempt
to access the PIB at the same time, thus clobbering each other
in the process.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: default avatarEddie James <eajames@linux.vnet.ibm.com>
parent 11454d6d

drivers/fsi/fsi-scom.c

+18 −7
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ struct scom_device { 
	struct list_head link;

	struct fsi_device *fsi_dev;

	struct miscdevice mdev;

	struct mutex lock;

	char	name[32];

	int idx;

};
@@ -53,21 +54,26 @@ static int put_scom(struct scom_device *scom_dev, uint64_t value, 
	int rc;

	uint32_t data;



	mutex_lock(&scom_dev->lock);



	data = cpu_to_be32((value >> 32) & 0xffffffff);

	rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA0_REG, &data,

				sizeof(uint32_t));

	if (rc)

		return rc;

		goto bail;



	data = cpu_to_be32(value & 0xffffffff);

	rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA1_REG, &data,

				sizeof(uint32_t));

	if (rc)

		return rc;

		goto bail;



	data = cpu_to_be32(SCOM_WRITE_CMD | addr);

	return fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,

	rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,

				sizeof(uint32_t));

 bail:

	mutex_unlock(&scom_dev->lock);

	return rc;

}



static int get_scom(struct scom_device *scom_dev, uint64_t *value,
@@ -76,27 +82,31 @@ static int get_scom(struct scom_device *scom_dev, uint64_t *value, 
	uint32_t result, data;

	int rc;





	mutex_lock(&scom_dev->lock);

	*value = 0ULL;

	data = cpu_to_be32(addr);

	rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,

				sizeof(uint32_t));

	if (rc)

		return rc;

		goto bail;



	rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA0_REG, &result,

				sizeof(uint32_t));

	if (rc)

		return rc;

		goto bail;



	*value |= (uint64_t)cpu_to_be32(result) << 32;

	rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &result,

				sizeof(uint32_t));

	if (rc)

		return rc;

		goto bail;



	*value |= cpu_to_be32(result);



	return 0;

 bail:

	mutex_unlock(&scom_dev->lock);

	return rc;

}



static ssize_t scom_read(struct file *filep, char __user *buf, size_t len,
@@ -183,6 +193,7 @@ static int scom_probe(struct device *dev) 
	if (!scom)

		return -ENOMEM;



	mutex_init(&scom->lock);

	scom->idx = ida_simple_get(&scom_ida, 1, INT_MAX, GFP_KERNEL);

	snprintf(scom->name, sizeof(scom->name), "scom%d", scom->idx);

	scom->fsi_dev = fsi_dev;