| /* |
| * 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" |
| |
| struct ba_bits { |
| unsigned allocated:1; /* 1 if allocated, 0 if free */ |
| unsigned order:7; /* size of the region in ba space */ |
| }; |
| |
| struct ba_info { |
| /* start address of the ba space */ |
| unsigned long base; |
| /* total size of the ba space */ |
| unsigned long size; |
| /* number of entries in the ba space */ |
| int num_entries; |
| /* the bitmap for the region indicating which entries are allocated |
| * and which are free */ |
| struct ba_bits *bitmap; |
| }; |
| |
| #undef min |
| #define min(a,b) ((a)<(b)?(a):(b)) |
| |
| #define BA_MIN_ALLOC LIBINC |
| #define BA_MAX_ORDER 128 |
| #define BA_START LIBBASE |
| #define BA_SIZE (LIBLAST - LIBBASE) |
| |
| #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 struct ba_bits ba_bitmap[BA_SIZE / BA_MIN_ALLOC]; |
| |
| static struct ba_info ba = { |
| .base = BA_START, |
| .size = BA_SIZE, |
| .bitmap = ba_bitmap, |
| .num_entries = sizeof(ba_bitmap)/sizeof(ba_bitmap[0]), |
| }; |
| |
| void ba_init(void) |
| { |
| int i, index = 0; |
| 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(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(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(unsigned long len) |
| { |
| int curr = 0; |
| int end = ba.num_entries; |
| int best_fit = -1; |
| unsigned long order = ba_order(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(int index) |
| { |
| return BA_START_ADDR(index); |
| } |
| |
| unsigned long ba_len(int index) |
| { |
| return BA_LEN(index); |
| } |