VisionFive2 Linux kernel

b24413180f560 (Greg Kroah-Hartman 2017-11-01 15:07:57 +0100  1) // SPDX-License-Identifier: GPL-2.0
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700  2) #include <linux/export.h>
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700  3) #include <linux/bug.h>
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700  4) #include <linux/bitmap.h>
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700  5) 
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700  6) /**
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700  7)  * memweight - count the total number of bits set in memory area
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700  8)  * @ptr: pointer to the start of the area
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700  9)  * @bytes: the size of the area
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 10)  */
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 11) size_t memweight(const void *ptr, size_t bytes)
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 12) {
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 13) 	size_t ret = 0;
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 14) 	size_t longs;
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 15) 	const unsigned char *bitmap = ptr;
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 16) 
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 17) 	for (; bytes > 0 && ((unsigned long)bitmap) % sizeof(long);
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 18) 			bytes--, bitmap++)
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 19) 		ret += hweight8(*bitmap);
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 20) 
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 21) 	longs = bytes / sizeof(long);
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 22) 	if (longs) {
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 23) 		BUG_ON(longs >= INT_MAX / BITS_PER_LONG);
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 24) 		ret += bitmap_weight((unsigned long *)bitmap,
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 25) 				longs * BITS_PER_LONG);
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 26) 		bytes -= longs * sizeof(long);
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 27) 		bitmap += longs * sizeof(long);
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 28) 	}
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 29) 	/*
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 30) 	 * The reason that this last loop is distinct from the preceding
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 31) 	 * bitmap_weight() call is to compute 1-bits in the last region smaller
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 32) 	 * than sizeof(long) properly on big-endian systems.
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 33) 	 */
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 34) 	for (; bytes > 0; bytes--, bitmap++)
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 35) 		ret += hweight8(*bitmap);
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 36) 
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 37) 	return ret;
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 38) }
639b9e34f15e4 (Akinobu Mita       2012-07-30 14:40:55 -0700 39) EXPORT_SYMBOL(memweight);