bitkeeper revision 1.1389.10.1 (427fa2d3ZV92f_ErvLuIzWbV1f67QA)

Phase 1 of upgrading platform code to be derived from Linux 2.6.11
rather than 2.4.x.
Signed-off-by: Keir Fraser <keir@xensource.com>

1 files changed, 365 insertions, 0 deletions

diff --git a/xen/common/bitmap.c b/xen/common/bitmap.c
new file mode 100644
index 0000000000..d931eca83c
--- /dev/null
+++ b/xen/common/bitmap.c
@@ -0,0 +1,365 @@
+/*
+ * lib/bitmap.c
+ * Helper functions for bitmap.h.
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+#include <xen/config.h>
+#include <xen/types.h>
+#include <xen/errno.h>
+#include <xen/bitmap.h>
+#include <xen/bitops.h>
+#include <asm/uaccess.h>
+
+/*
+ * bitmaps provide an array of bits, implemented using an an
+ * array of unsigned longs.  The number of valid bits in a
+ * given bitmap does _not_ need to be an exact multiple of
+ * BITS_PER_LONG.
+ *
+ * The possible unused bits in the last, partially used word
+ * of a bitmap are 'don't care'.  The implementation makes
+ * no particular effort to keep them zero.  It ensures that
+ * their value will not affect the results of any operation.
+ * The bitmap operations that return Boolean (bitmap_empty,
+ * for example) or scalar (bitmap_weight, for example) results
+ * carefully filter out these unused bits from impacting their
+ * results.
+ *
+ * These operations actually hold to a slightly stronger rule:
+ * if you don't input any bitmaps to these ops that have some
+ * unused bits set, then they won't output any set unused bits
+ * in output bitmaps.
+ *
+ * The byte ordering of bitmaps is more natural on little
+ * endian architectures.  See the big-endian headers
+ * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
+ * for the best explanations of this ordering.
+ */
+
+int __bitmap_empty(const unsigned long *bitmap, int bits)
+{
+	int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
+		if (bitmap[k])
+			return 0;
+
+	if (bits % BITS_PER_LONG)
+		if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
+			return 0;
+
+	return 1;
+}
+EXPORT_SYMBOL(__bitmap_empty);
+
+int __bitmap_full(const unsigned long *bitmap, int bits)
+{
+	int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
+		if (~bitmap[k])
+			return 0;
+
+	if (bits % BITS_PER_LONG)
+		if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
+			return 0;
+
+	return 1;
+}
+EXPORT_SYMBOL(__bitmap_full);
+
+int __bitmap_equal(const unsigned long *bitmap1,
+		const unsigned long *bitmap2, int bits)
+{
+	int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
+		if (bitmap1[k] != bitmap2[k])
+			return 0;
+
+	if (bits % BITS_PER_LONG)
+		if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
+			return 0;
+
+	return 1;
+}
+EXPORT_SYMBOL(__bitmap_equal);
+
+void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
+{
+	int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
+		dst[k] = ~src[k];
+
+	if (bits % BITS_PER_LONG)
+		dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
+}
+EXPORT_SYMBOL(__bitmap_complement);
+
+/*
+ * __bitmap_shift_right - logical right shift of the bits in a bitmap
+ *   @dst - destination bitmap
+ *   @src - source bitmap
+ *   @nbits - shift by this many bits
+ *   @bits - bitmap size, in bits
+ *
+ * Shifting right (dividing) means moving bits in the MS -> LS bit
+ * direction.  Zeros are fed into the vacated MS positions and the
+ * LS bits shifted off the bottom are lost.
+ */
+void __bitmap_shift_right(unsigned long *dst,
+			const unsigned long *src, int shift, int bits)
+{
+	int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
+	int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
+	unsigned long mask = (1UL << left) - 1;
+	for (k = 0; off + k < lim; ++k) {
+		unsigned long upper, lower;
+
+		/*
+		 * If shift is not word aligned, take lower rem bits of
+		 * word above and make them the top rem bits of result.
+		 */
+		if (!rem || off + k + 1 >= lim)
+			upper = 0;
+		else {
+			upper = src[off + k + 1];
+			if (off + k + 1 == lim - 1 && left)
+				upper &= mask;
+		}
+		lower = src[off + k];
+		if (left && off + k == lim - 1)
+			lower &= mask;
+		dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
+		if (left && k == lim - 1)
+			dst[k] &= mask;
+	}
+	if (off)
+		memset(&dst[lim - off], 0, off*sizeof(unsigned long));
+}
+EXPORT_SYMBOL(__bitmap_shift_right);
+
+
+/*
+ * __bitmap_shift_left - logical left shift of the bits in a bitmap
+ *   @dst - destination bitmap
+ *   @src - source bitmap
+ *   @nbits - shift by this many bits
+ *   @bits - bitmap size, in bits
+ *
+ * Shifting left (multiplying) means moving bits in the LS -> MS
+ * direction.  Zeros are fed into the vacated LS bit positions
+ * and those MS bits shifted off the top are lost.
+ */
+
+void __bitmap_shift_left(unsigned long *dst,
+			const unsigned long *src, int shift, int bits)
+{
+	int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
+	int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
+	for (k = lim - off - 1; k >= 0; --k) {
+		unsigned long upper, lower;
+
+		/*
+		 * If shift is not word aligned, take upper rem bits of
+		 * word below and make them the bottom rem bits of result.
+		 */
+		if (rem && k > 0)
+			lower = src[k - 1];
+		else
+			lower = 0;
+		upper = src[k];
+		if (left && k == lim - 1)
+			upper &= (1UL << left) - 1;
+		dst[k + off] = lower  >> (BITS_PER_LONG - rem) | upper << rem;
+		if (left && k + off == lim - 1)
+			dst[k + off] &= (1UL << left) - 1;
+	}
+	if (off)
+		memset(dst, 0, off*sizeof(unsigned long));
+}
+EXPORT_SYMBOL(__bitmap_shift_left);
+
+void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
+				const unsigned long *bitmap2, int bits)
+{
+	int k;
+	int nr = BITS_TO_LONGS(bits);
+
+	for (k = 0; k < nr; k++)
+		dst[k] = bitmap1[k] & bitmap2[k];
+}
+EXPORT_SYMBOL(__bitmap_and);
+
+void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
+				const unsigned long *bitmap2, int bits)
+{
+	int k;
+	int nr = BITS_TO_LONGS(bits);
+
+	for (k = 0; k < nr; k++)
+		dst[k] = bitmap1[k] | bitmap2[k];
+}
+EXPORT_SYMBOL(__bitmap_or);
+
+void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
+				const unsigned long *bitmap2, int bits)
+{
+	int k;
+	int nr = BITS_TO_LONGS(bits);
+
+	for (k = 0; k < nr; k++)
+		dst[k] = bitmap1[k] ^ bitmap2[k];
+}
+EXPORT_SYMBOL(__bitmap_xor);
+
+void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
+				const unsigned long *bitmap2, int bits)
+{
+	int k;
+	int nr = BITS_TO_LONGS(bits);
+
+	for (k = 0; k < nr; k++)
+		dst[k] = bitmap1[k] & ~bitmap2[k];
+}
+EXPORT_SYMBOL(__bitmap_andnot);
+
+int __bitmap_intersects(const unsigned long *bitmap1,
+				const unsigned long *bitmap2, int bits)
+{
+	int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
+		if (bitmap1[k] & bitmap2[k])
+			return 1;
+
+	if (bits % BITS_PER_LONG)
+		if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
+			return 1;
+	return 0;
+}
+EXPORT_SYMBOL(__bitmap_intersects);
+
+int __bitmap_subset(const unsigned long *bitmap1,
+				const unsigned long *bitmap2, int bits)
+{
+	int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
+		if (bitmap1[k] & ~bitmap2[k])
+			return 0;
+
+	if (bits % BITS_PER_LONG)
+		if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
+			return 0;
+	return 1;
+}
+EXPORT_SYMBOL(__bitmap_subset);
+
+#if BITS_PER_LONG == 32
+int __bitmap_weight(const unsigned long *bitmap, int bits)
+{
+	int k, w = 0, lim = bits/BITS_PER_LONG;
+
+	for (k = 0; k < lim; k++)
+		w += hweight32(bitmap[k]);
+
+	if (bits % BITS_PER_LONG)
+		w += hweight32(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
+
+	return w;
+}
+#else
+int __bitmap_weight(const unsigned long *bitmap, int bits)
+{
+	int k, w = 0, lim = bits/BITS_PER_LONG;
+
+	for (k = 0; k < lim; k++)
+		w += hweight64(bitmap[k]);
+
+	if (bits % BITS_PER_LONG)
+		w += hweight64(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
+
+	return w;
+}
+#endif
+EXPORT_SYMBOL(__bitmap_weight);
+
+/**
+ *	bitmap_find_free_region - find a contiguous aligned mem region
+ *	@bitmap: an array of unsigned longs corresponding to the bitmap
+ *	@bits: number of bits in the bitmap
+ *	@order: region size to find (size is actually 1<<order)
+ *
+ * This is used to allocate a memory region from a bitmap.  The idea is
+ * that the region has to be 1<<order sized and 1<<order aligned (this
+ * makes the search algorithm much faster).
+ *
+ * The region is marked as set bits in the bitmap if a free one is
+ * found.
+ *
+ * Returns either beginning of region or negative error
+ */
+int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
+{
+	unsigned long mask;
+	int pages = 1 << order;
+	int i;
+
+	if(pages > BITS_PER_LONG)
+		return -EINVAL;
+
+	/* make a mask of the order */
+	mask = (1ul << (pages - 1));
+	mask += mask - 1;
+
+	/* run up the bitmap pages bits at a time */
+	for (i = 0; i < bits; i += pages) {
+		int index = i/BITS_PER_LONG;
+		int offset = i - (index * BITS_PER_LONG);
+		if((bitmap[index] & (mask << offset)) == 0) {
+			/* set region in bimap */
+			bitmap[index] |= (mask << offset);
+			return i;
+		}
+	}
+	return -ENOMEM;
+}
+EXPORT_SYMBOL(bitmap_find_free_region);
+
+/**
+ *	bitmap_release_region - release allocated bitmap region
+ *	@bitmap: a pointer to the bitmap
+ *	@pos: the beginning of the region
+ *	@order: the order of the bits to release (number is 1<<order)
+ *
+ * This is the complement to __bitmap_find_free_region and releases
+ * the found region (by clearing it in the bitmap).
+ */
+void bitmap_release_region(unsigned long *bitmap, int pos, int order)
+{
+	int pages = 1 << order;
+	unsigned long mask = (1ul << (pages - 1));
+	int index = pos/BITS_PER_LONG;
+	int offset = pos - (index * BITS_PER_LONG);
+	mask += mask - 1;
+	bitmap[index] &= ~(mask << offset);
+}
+EXPORT_SYMBOL(bitmap_release_region);
+
+int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
+{
+	int pages = 1 << order;
+	unsigned long mask = (1ul << (pages - 1));
+	int index = pos/BITS_PER_LONG;
+	int offset = pos - (index * BITS_PER_LONG);
+
+	/* We don't do regions of pages > BITS_PER_LONG.  The
+	 * algorithm would be a simple look for multiple zeros in the
+	 * array, but there's no driver today that needs this.  If you
+	 * trip this BUG(), you get to code it... */
+	BUG_ON(pages > BITS_PER_LONG);
+	mask += mask - 1;
+	if (bitmap[index] & (mask << offset))
+		return -EBUSY;
+	bitmap[index] |= (mask << offset);
+	return 0;
+}
+EXPORT_SYMBOL(bitmap_allocate_region);