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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2018-06-12 08:19:07 +0300
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2018-06-18 07:33:56 +0300
commit162c3946734d1f1950b413bbb3182d76d5be484b (patch)
tree8851f40603b3e88d4f1ed4fef1cb0d26261c9761 /drivers/fsi
parent11454d6dc81813edb085b63b43b2e4df5e006218 (diff)
downloadlinux-162c3946734d1f1950b413bbb3182d76d5be484b.tar.xz
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>
Diffstat (limited to 'drivers/fsi')
-rw-r--r--drivers/fsi/fsi-scom.c25
1 files changed, 18 insertions, 7 deletions
diff --git a/drivers/fsi/fsi-scom.c b/drivers/fsi/fsi-scom.c
index c8eb5e5b94a7..3cba0eb645e1 100644
--- a/drivers/fsi/fsi-scom.c
+++ b/drivers/fsi/fsi-scom.c
@@ -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;