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SubjectRe: [PATCH v2 4/4] remoteproc: debugfs: Add ability to boot remote processor using debugfs
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On 08/28/2015 05:31 AM, Lee Jones wrote:
> +static ssize_t rproc_state_write(struct file *filp, const char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + struct rproc *rproc = filp->private_data;
> + char buf[2];
> + int ret;
> +
> + ret = copy_from_user(buf, userbuf, 1);
> + if (ret)
> + return -EFAULT;
> +
> + switch (buf[0]) {
> + case '0':
> + rproc_shutdown(rproc);
> + break;
> + case '1':
> + ret = rproc_boot(rproc);
> + if (ret)
> + dev_warn(&rproc->dev, "Boot failed: %d\n", ret);
> + break;
> + default:
> + dev_err(&rproc->dev, "Unrecognised option: %x\n", buf[1]);
> + return -EINVAL;

This prints uninitialized kernel stack contents instead of what was
copied from user space.

Is the dev_err statement really necessary anyway?


> + }
> +
> + return count;
> +}

If rproc_boot fails, that should be reflected in the syscall result.

This interface is essentially exposing the remoteproc->power refcount to
user space; is that okay? Seems like it makes it easy to underflow
remoteproc->power through successive shutdown calls.

The other debugfs interface in remoteproc that has a write method
(recovery) accepts more expressive string commands as opposed to 0/1.
It would be more consistent for this interface to take commands such as
"boot" and "shutdown" IMO.



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