tree:   https://github.com/ammarfaizi2/linux-block crng/random/vdso
head:   f1dcde1339efb8adc21b29142bfbdb8a026348d0
commit: 030205da92b1beb7f36a238d06486cf74dd15b2a [20/22] random: add vgetrandom_alloc() syscall
config: arc-randconfig-r043-20221127
compiler: arceb-elf-gcc (GCC) 12.1.0
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/ammarfaizi2/linux-block/commit/030205da92b1beb7f36a238d06486cf74dd15b2a
        git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block
        git fetch --no-tags ammarfaizi2-block crng/random/vdso
        git checkout 030205da92b1beb7f36a238d06486cf74dd15b2a
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arc SHELL=/bin/bash drivers/char/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   drivers/char/random.c:201: warning: bad line: 
>> drivers/char/random.c:207: warning: expecting prototype for vgetrandom_alloc(). Prototype was for sys_vgetrandom_alloc() instead


vim +207 drivers/char/random.c

   166	
   167	#define warn_unseeded_randomness() \
   168		if (IS_ENABLED(CONFIG_WARN_ALL_UNSEEDED_RANDOM) && !crng_ready()) \
   169			printk_deferred(KERN_NOTICE "random: %s called from %pS with crng_init=%d\n", \
   170					__func__, (void *)_RET_IP_, crng_init)
   171	
   172	
   173	
   174	/********************************************************************
   175	 *
   176	 * vDSO support helpers.
   177	 *
   178	 * The actual vDSO function is defined over in lib/vdso/getrandom.c,
   179	 * but this section contains the kernel-mode helpers to support that.
   180	 *
   181	 ********************************************************************/
   182	
   183	#if IS_ENABLED(CONFIG_VGETRANDOM_ALLOC_SYSCALL)
   184	/**
   185	 * vgetrandom_alloc - allocate opaque states for use with vDSO getrandom().
   186	 *
   187	 * @num: on input, a pointer to a suggested hint of how many states to
   188	 * allocate, and on output the number of states actually allocated.
   189	 *
   190	 * @size_per_each: the size of each state allocated, so that the caller can
   191	 * split up the returned allocation into individual states.
   192	 *
   193	 * @flags: currently always zero.
   194	 *
   195	 * The getrandom() vDSO function in userspace requires an opaque state, which
   196	 * this function allocates by mapping a certain number of special pages into
   197	 * the calling process. It takes a hint as to the number of opaque states
   198	 * desired, and provides the caller with the number of opaque states actually
   199	 * allocated, the size of each one in bytes, and the address of the first
   200	 * state.
   201	
   202	 * Returns a pointer to the first state in the allocation.
   203	 *
   204	 */
   205	SYSCALL_DEFINE3(vgetrandom_alloc, unsigned int __user *, num,
   206			unsigned int __user *, size_per_each, unsigned int, flags)
 > 207	{
   208		const size_t state_size = sizeof(struct vgetrandom_state);
   209		size_t alloc_size, num_states;
   210		unsigned long pages_addr;
   211		unsigned int num_hint;
   212		int ret;
   213	
   214		if (flags)
   215			return -EINVAL;
   216	
   217		if (get_user(num_hint, num))
   218			return -EFAULT;
   219	
   220		num_states = clamp_t(size_t, num_hint, 1, (SIZE_MAX & PAGE_MASK) / state_size);
   221		alloc_size = PAGE_ALIGN(num_states * state_size);
   222	
   223		if (put_user(alloc_size / state_size, num) || put_user(state_size, size_per_each))
   224			return -EFAULT;
   225	
   226		pages_addr = vm_mmap(NULL, 0, alloc_size, PROT_READ | PROT_WRITE,
   227				     MAP_PRIVATE | MAP_ANONYMOUS | MAP_LOCKED, 0);
   228		if (IS_ERR_VALUE(pages_addr))
   229			return pages_addr;
   230	
   231		ret = do_madvise(current->mm, pages_addr, alloc_size, MADV_WIPEONFORK);
   232		if (ret < 0)
   233			goto err_unmap;
   234	
   235		return pages_addr;
   236	
   237	err_unmap:
   238		vm_munmap(pages_addr, alloc_size);
   239		return ret;
   240	}
   241	#endif
   242	

-- 
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