Re: [PATCH v3 2/2] misc: open-dice: Add driver to expose DICE data to userspace

[kernel test robot <lkp@xxxxxxxxx>]

Hi David,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on robh/for-next]
[also build test WARNING on char-misc/char-misc-testing soc/for-next v5.16-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/David-Brazdil/Driver-for-Open-Profile-for-DICE/20211214-040051
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
config: sh-allmodconfig (https://download.01.org/0day-ci/archive/20211214/202112141128.lBBmmIuE-lkp@xxxxxxxxx/config)
compiler: sh4-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/6fb8e9472d98abcc2dfabd43e95fc4ec5819ecd0
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review David-Brazdil/Driver-for-Open-Profile-for-DICE/20211214-040051
        git checkout 6fb8e9472d98abcc2dfabd43e95fc4ec5819ecd0
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=sh SHELL=/bin/bash drivers/misc/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

   drivers/misc/open-dice.c:74: warning: Function parameter or member 'filp' not described in 'open_dice_read'
   drivers/misc/open-dice.c:74: warning: Function parameter or member 'ptr' not described in 'open_dice_read'
   drivers/misc/open-dice.c:74: warning: Function parameter or member 'len' not described in 'open_dice_read'
   drivers/misc/open-dice.c:74: warning: Function parameter or member 'off' not described in 'open_dice_read'
>> drivers/misc/open-dice.c:74: warning: expecting prototype for Returns the size of the reserved memory region. The user(). Prototype was for open_dice_read() instead
   drivers/misc/open-dice.c:84: warning: Function parameter or member 'filp' not described in 'open_dice_write'
   drivers/misc/open-dice.c:84: warning: Function parameter or member 'ptr' not described in 'open_dice_write'
   drivers/misc/open-dice.c:84: warning: Function parameter or member 'len' not described in 'open_dice_write'
   drivers/misc/open-dice.c:84: warning: Function parameter or member 'off' not described in 'open_dice_write'
>> drivers/misc/open-dice.c:84: warning: expecting prototype for Triggers a wipe of the reserved memory region. The user(). Prototype was for open_dice_write() instead
>> drivers/misc/open-dice.c:89: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
    * Creates a mapping of the reserved memory region in a user address space.


vim +74 drivers/misc/open-dice.c

    67	
    68	/**
    69	 * Returns the size of the reserved memory region. The user-provided pointer is
    70	 * never dereferenced.
    71	 */
    72	static ssize_t open_dice_read(struct file *filp, char __user *ptr, size_t len,
    73				      loff_t *off)
  > 74	{
    75		return open_dice_size(to_open_dice_drvdata(filp));
    76	}
    77	
    78	/**
    79	 * Triggers a wipe of the reserved memory region. The user-provided pointer is
    80	 * never dereferenced.
    81	 */
    82	static ssize_t open_dice_write(struct file *filp, const char __user *ptr,
    83				       size_t len, loff_t *off)
  > 84	{
    85		return open_dice_wipe(to_open_dice_drvdata(filp));
    86	}
    87	
    88	/**
  > 89	 * Creates a mapping of the reserved memory region in a user address space.
    90	 */
    91	static int open_dice_mmap(struct file *filp, struct vm_area_struct *vma)
    92	{
    93		struct open_dice_drvdata *drvdata = to_open_dice_drvdata(filp);
    94	
    95		/* Do not allow userspace to modify the underlying data. */
    96		if ((vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_SHARED))
    97			return -EPERM;
    98	
    99		/* Create write-combine mapping so all clients observe a wipe. */
   100		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
   101		vma->vm_flags |= VM_DONTCOPY | VM_DONTDUMP;
   102		return vm_iomap_memory(vma, drvdata->rmem->base, drvdata->rmem->size);
   103	}
   104	

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