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Re: [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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[PATCH v2 0/4] remoteproc: Add driver for STMicroelectronics platforms Lee Jones <lee.jones@linaro.org> - 2015-08-28 12:40 +0200
  [PATCH v2 2/4] remoteproc: dt: Provide bindings for ST's Remote Processor Controller driver Lee Jones <lee.jones@linaro.org> - 2015-08-28 12:40 +0200
    Re: [PATCH v2 2/4] remoteproc: dt: Provide bindings for ST's Remote  Processor Controller driver Rob Herring <robherring2@gmail.com> - 2015-08-31 17:30 +0200
      Re: [PATCH v2 2/4] remoteproc: dt: Provide bindings for ST's Remote  Processor Controller driver Lee Jones <lee.jones@linaro.org> - 2015-09-01 12:50 +0200
        Re: [PATCH v2 2/4] remoteproc: dt: Provide bindings for ST's Remote  Processor Controller driver Rob Herring <robherring2@gmail.com> - 2015-09-01 14:00 +0200
    Re: [STLinux Kernel] [PATCH v2 2/4] remoteproc: dt: Provide bindings  for ST's Remote Processor Controller driver Peter Griffin <peter.griffin@linaro.org> - 2015-09-01 11:00 +0200
      Re: [STLinux Kernel] [PATCH v2 2/4] remoteproc: dt: Provide bindings  for ST's Remote Processor Controller driver Lee Jones <lee.jones@linaro.org> - 2015-09-01 11:20 +0200
      Re: [STLinux Kernel] [PATCH v2 2/4] remoteproc: dt: Provide bindings  for ST's Remote Processor Controller driver Lee Jones <lee.jones@linaro.org> - 2015-09-01 15:00 +0200
  [PATCH v2 3/4] remoteproc: Supply controller driver for ST's Remote Processors Lee Jones <lee.jones@linaro.org> - 2015-08-28 12:40 +0200
    Re: [PATCH v2 3/4] remoteproc: Supply controller driver for ST's  Remote Processors Nathan Lynch <Nathan_Lynch@mentor.com> - 2015-08-28 18:30 +0200
      Re: [PATCH v2 3/4] remoteproc: Supply controller driver for ST's  Remote Processors Lee Jones <lee.jones@linaro.org> - 2015-09-01 10:00 +0200
        Re: [STLinux Kernel] [PATCH v2 3/4] remoteproc: Supply controller  driver for ST's Remote Processors Peter Griffin <peter.griffin@linaro.org> - 2015-09-01 10:20 +0200
          Re: [STLinux Kernel] [PATCH v2 3/4] remoteproc: Supply controller  driver for ST's Remote Processors Lee Jones <lee.jones@linaro.org> - 2015-09-01 11:20 +0200
  [PATCH v2 4/4] remoteproc: debugfs: Add ability to boot remote processor using debugfs Lee Jones <lee.jones@linaro.org> - 2015-08-28 12:40 +0200
    Re: [PATCH v2 4/4] remoteproc: debugfs: Add ability to boot remote  processor using debugfs Nathan Lynch <Nathan_Lynch@mentor.com> - 2015-08-28 17:30 +0200
      Re: [PATCH v2 4/4] remoteproc: debugfs: Add ability to boot remote  processor using debugfs Lee Jones <lee.jones@linaro.org> - 2015-09-01 09:50 +0200
    Re: [PATCH v2 4/4] remoteproc: debugfs: Add ability to boot remote  processor using debugfs Florian Fainelli <f.fainelli@gmail.com> - 2015-08-28 19:30 +0200
      Re: [PATCH v2 4/4] remoteproc: debugfs: Add ability to boot remote  processor using debugfs Lee Jones <lee.jones@linaro.org> - 2015-09-01 09:50 +0200
  [PATCH v2 1/4] ARM: STiH407: Add nodes for RemoteProc Lee Jones <lee.jones@linaro.org> - 2015-08-28 12:40 +0200
    Re: [STLinux Kernel] [PATCH v2 1/4] ARM: STiH407: Add nodes for  RemoteProc Peter Griffin <peter.griffin@linaro.org> - 2015-09-01 10:30 +0200
      Re: [STLinux Kernel] [PATCH v2 1/4] ARM: STiH407: Add nodes for  RemoteProc Lee Jones <lee.jones@linaro.org> - 2015-09-01 11:20 +0200
        Re: [STLinux Kernel] [PATCH v2 1/4] ARM: STiH407: Add nodes for  RemoteProc Peter Griffin <peter.griffin@linaro.org> - 2015-09-01 11:20 +0200

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