Revert "linker: get rid of the buddy allocator"
This reverts commit 7059b1f02ea9197728c851edd9ae0dd7688fa700.
Bug: 5036610
diff --git a/linker/ba.c b/linker/ba.c
new file mode 100644
index 0000000..db49c4b
--- /dev/null
+++ b/linker/ba.c
@@ -0,0 +1,156 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "linker.h"
+#include "linker_debug.h"
+#include "ba.h"
+
+#undef min
+#define min(a,b) ((a)<(b)?(a):(b))
+
+#define BA_IS_FREE(index) (!(ba->bitmap[index].allocated))
+#define BA_ORDER(index) ba->bitmap[index].order
+#define BA_BUDDY_INDEX(index) ((index) ^ (1 << BA_ORDER(index)))
+#define BA_NEXT_INDEX(index) ((index) + (1 << BA_ORDER(index)))
+#define BA_OFFSET(index) ((index) * ba->min_alloc)
+#define BA_START_ADDR(index) (BA_OFFSET(index) + ba->base)
+#define BA_LEN(index) ((1 << BA_ORDER(index)) * ba->min_alloc)
+
+static unsigned long ba_order(struct ba *ba, unsigned long len);
+
+void ba_init(struct ba *ba)
+{
+ int i, index = 0;
+
+ unsigned long max_order = ba_order(ba, ba->size);
+ if (ba->max_order == 0 || ba->max_order > max_order)
+ ba->max_order = max_order;
+
+ for (i = sizeof(ba->num_entries) * 8 - 1; i >= 0; i--) {
+ if (ba->num_entries & 1<<i) {
+ BA_ORDER(index) = i;
+ index = BA_NEXT_INDEX(index);
+ }
+ }
+}
+
+int ba_free(struct ba *ba, int index)
+{
+ int buddy, curr = index;
+
+ /* clean up the bitmap, merging any buddies */
+ ba->bitmap[curr].allocated = 0;
+ /* find a slots buddy Buddy# = Slot# ^ (1 << order)
+ * if the buddy is also free merge them
+ * repeat until the buddy is not free or end of the bitmap is reached
+ */
+ do {
+ buddy = BA_BUDDY_INDEX(curr);
+ if (BA_IS_FREE(buddy) &&
+ BA_ORDER(buddy) == BA_ORDER(curr)) {
+ BA_ORDER(buddy)++;
+ BA_ORDER(curr)++;
+ curr = min(buddy, curr);
+ } else {
+ break;
+ }
+ } while (curr < ba->num_entries);
+
+ return 0;
+}
+
+static unsigned long ba_order(struct ba *ba, unsigned long len)
+{
+ unsigned long i;
+
+ len = (len + ba->min_alloc - 1) / ba->min_alloc;
+ len--;
+ for (i = 0; i < sizeof(len)*8; i++)
+ if (len >> i == 0)
+ break;
+ return i;
+}
+
+int ba_allocate(struct ba *ba, unsigned long len)
+{
+ int curr = 0;
+ int end = ba->num_entries;
+ int best_fit = -1;
+ unsigned long order = ba_order(ba, len);
+
+ if (order > ba->max_order)
+ return -1;
+
+ /* look through the bitmap:
+ * if you find a free slot of the correct order use it
+ * otherwise, use the best fit (smallest with size > order) slot
+ */
+ while (curr < end) {
+ if (BA_IS_FREE(curr)) {
+ if (BA_ORDER(curr) == (unsigned char)order) {
+ /* set the not free bit and clear others */
+ best_fit = curr;
+ break;
+ }
+ if (BA_ORDER(curr) > (unsigned char)order &&
+ (best_fit < 0 ||
+ BA_ORDER(curr) < BA_ORDER(best_fit)))
+ best_fit = curr;
+ }
+ curr = BA_NEXT_INDEX(curr);
+ }
+
+ /* if best_fit < 0, there are no suitable slots,
+ * return an error
+ */
+ if (best_fit < 0)
+ return -1;
+
+ /* now partition the best fit:
+ * split the slot into 2 buddies of order - 1
+ * repeat until the slot is of the correct order
+ */
+ while (BA_ORDER(best_fit) > (unsigned char)order) {
+ int buddy;
+ BA_ORDER(best_fit) -= 1;
+ buddy = BA_BUDDY_INDEX(best_fit);
+ BA_ORDER(buddy) = BA_ORDER(best_fit);
+ }
+ ba->bitmap[best_fit].allocated = 1;
+ return best_fit;
+}
+
+unsigned long ba_start_addr(struct ba *ba, int index)
+{
+ return BA_START_ADDR(index);
+}
+
+unsigned long ba_len(struct ba *ba, int index)
+{
+ return BA_LEN(index);
+}