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platform_kernel-5.15
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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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
This commit is contained in:
Benjamin Herrenschmidt 2018-06-12 15:19:07 +10:00
parent 11454d6dc8
commit 162c394673
1 changed files with 18 additions and 7 deletions
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25
drivers/fsi/fsi-scom.c
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@ -37,6 +37,7 @@ struct scom_device {
struct list_head link; struct list_head link;
struct fsi_device *fsi_dev; struct fsi_device *fsi_dev;
struct miscdevice mdev; struct miscdevice mdev;
struct mutex lock;
char name[32]; char name[32];
int idx; int idx;
}; };
@ -53,21 +54,26 @@ static int put_scom(struct scom_device *scom_dev, uint64_t value,
int rc; int rc;
uint32_t data; uint32_t data;
mutex_lock(&scom_dev->lock);
data = cpu_to_be32((value >> 32) & 0xffffffff); data = cpu_to_be32((value >> 32) & 0xffffffff);
rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA0_REG, &data, rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA0_REG, &data,
sizeof(uint32_t)); sizeof(uint32_t));
if (rc) if (rc)
return rc; goto bail;
data = cpu_to_be32(value & 0xffffffff); data = cpu_to_be32(value & 0xffffffff);
rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA1_REG, &data, rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA1_REG, &data,
sizeof(uint32_t)); sizeof(uint32_t));
if (rc) if (rc)
return rc; goto bail;
data = cpu_to_be32(SCOM_WRITE_CMD | addr); 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)); sizeof(uint32_t));
bail:
mutex_unlock(&scom_dev->lock);
return rc;
} }
static int get_scom(struct scom_device *scom_dev, uint64_t *value, 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; uint32_t result, data;
int rc; int rc;
mutex_lock(&scom_dev->lock);
*value = 0ULL; *value = 0ULL;
data = cpu_to_be32(addr); data = cpu_to_be32(addr);
rc = 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)); sizeof(uint32_t));
if (rc) if (rc)
return rc; goto bail;
rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA0_REG, &result, rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA0_REG, &result,
sizeof(uint32_t)); sizeof(uint32_t));
if (rc) if (rc)
return rc; goto bail;
*value |= (uint64_t)cpu_to_be32(result) << 32; *value |= (uint64_t)cpu_to_be32(result) << 32;
rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &result, rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &result,
sizeof(uint32_t)); sizeof(uint32_t));
if (rc) if (rc)
return rc; goto bail;
*value |= cpu_to_be32(result); *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, 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) if (!scom)
return -ENOMEM; return -ENOMEM;
mutex_init(&scom->lock);
scom->idx = ida_simple_get(&scom_ida, 1, INT_MAX, GFP_KERNEL); scom->idx = ida_simple_get(&scom_ida, 1, INT_MAX, GFP_KERNEL);
snprintf(scom->name, sizeof(scom->name), "scom%d", scom->idx); snprintf(scom->name, sizeof(scom->name), "scom%d", scom->idx);
scom->fsi_dev = fsi_dev; scom->fsi_dev = fsi_dev;