Hello Oleksandr-
On Tue, Jan 16, 2018 at 09:18:56AM +0200, Oleksandr Shamray wrote:
[..]
> v16->v17
> Comments pointed by Julia Cartwright <juliac@xxxxxxxxxxxx>
More review feedback below:
[..]
> +++ b/drivers/jtag/jtag.c
[..]
> +static long jtag_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> +{
> + struct jtag *jtag = file->private_data;
> + struct jtag_run_test_idle idle;
> + struct jtag_xfer xfer;
> + u8 *xfer_data;
> + u32 data_size;
> + u32 value;
> + int err;
> +
> + if (!arg)
> + return -EINVAL;
> +
> + switch (cmd) {
> + case JTAG_GIOCFREQ:
> + if (!jtag->ops->freq_get)
> + err = -EOPNOTSUPP;
Did you mean:
return -EOPNOTSUPP;
?
> +
> + err = jtag->ops->freq_get(jtag, &value);
Otherwise you're check was worthless, you'll call NULL here.
Also, w.r.t. the set of ops which are required to be implemented: this
isn't the right place to do the check.
Instead, do it in jtag_alloc():
struct jtag *jtag_alloc(size_t priv_size, const struct jtag_ops *ops)
{
struct jtag *jtag;
if (!ops->freq_get || !ops->xfer || ...) /* fixup condition */
return NULL;
jtag = kzalloc(sizeof(*jtag) + priv_size, GFP_KERNEL);
if (!jtag)
return NULL;
jtag->ops = ops;
return jtag;
}
EXPORT_SYMBOL_GPL(jtag_alloc);
[..]
> + case JTAG_IOCXFER:
[..]
> + data_size = DIV_ROUND_UP(xfer.length, BITS_PER_BYTE);
> + xfer_data = memdup_user(u64_to_user_ptr(xfer.tdio), data_size);
> +
> + if (!xfer_data)
memdup_user() doesn't return NULL on error. You need to check for
IS_ERR(xfer_data).
> + return -EFAULT;
> +
> + err = jtag->ops->xfer(jtag, &xfer, xfer_data);
> + if (err) {
> + kfree(xfer_data);
> + return -EFAULT;
> + }
> +
> + err = copy_to_user(u64_to_user_ptr(xfer.tdio),
> + (void *)(xfer_data), data_size);
> +
> + if (err) {
> + kfree(xfer_data);
> + return -EFAULT;
> + }
> +
> + kfree(xfer_data);
Move the kfree() above the if (err).
> + if (copy_to_user((void *)arg, &xfer, sizeof(struct jtag_xfer)))
> + return -EFAULT;
> + break;
> +
> + case JTAG_GIOCSTATUS:
> + if (!jtag->ops->status_get)
> + return -EOPNOTSUPP;
> +
> + err = jtag->ops->status_get(jtag, &value);
> + if (err)
> + break;
> +
> + err = put_user(value, (__u32 *)arg);
> + if (err)
> + err = -EFAULT;
put_user() returns -EFAULT on failure, so this shouldn't be necessary.
[..]
> --- /dev/null
> +++ b/include/uapi/linux/jtag.h
[..]
> +/**
> + * struct jtag_xfer - jtag xfer:
> + *
> + * @type: transfer type
> + * @direction: xfer direction
> + * @length: xfer bits len
> + * @tdio : xfer data array
> + * @endir: xfer end state
> + *
> + * Structure represents interface to JTAG device for jtag sdr xfer
> + * execution.
> + */
> +struct jtag_xfer {
> + __u8 type;
> + __u8 direction;
> + __u8 endstate;
Just to be as unambiguous as possible, considering this is ABI, I would
suggest explicitly putting a padding byte here.
> + __u32 length;
> + __u64 tdio;
> +};
Thanks,
Julia
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