163 lines
4.6 KiB
C
163 lines
4.6 KiB
C
// Support for building memory maps suitable for int 15 e820 calls.
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//
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// Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
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//
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// This file may be distributed under the terms of the GNU LGPLv3 license.
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#include "memmap.h" // struct e820entry
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#include "util.h" // dprintf.h
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#include "biosvar.h" // SET_EBDA
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// Remove an entry from the e820_list.
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static void
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remove_e820(int i)
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{
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e820_count--;
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memmove(&e820_list[i], &e820_list[i+1]
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, sizeof(e820_list[0]) * (e820_count - i));
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}
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// Insert an entry in the e820_list at the given position.
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static void
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insert_e820(int i, u64 start, u64 size, u32 type)
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{
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if (e820_count >= CONFIG_MAX_E820) {
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dprintf(1, "Overflowed e820 list!\n");
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return;
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}
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memmove(&e820_list[i+1], &e820_list[i]
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, sizeof(e820_list[0]) * (e820_count - i));
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e820_count++;
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struct e820entry *e = &e820_list[i];
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e->start = start;
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e->size = size;
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e->type = type;
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}
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// Show the current e820_list.
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static void
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dump_map()
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{
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dprintf(1, "e820 map has %d items:\n", e820_count);
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int i;
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for (i=0; i<e820_count; i++) {
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struct e820entry *e = &e820_list[i];
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u64 e_end = e->start + e->size;
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dprintf(1, " %d: %x%x - %x%x = %d\n", i
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, (u32)(e->start >> 32), (u32)e->start
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, (u32)(e_end >> 32), (u32)e_end
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, e->type);
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}
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}
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// Add a new entry to the list. This scans for overlaps and keeps the
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// list sorted.
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void
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add_e820(u64 start, u64 size, u32 type)
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{
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dprintf(8, "Add to e820 map: %x %x %d\n", (u32)start, (u32)size, type);
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if (! size)
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// Huh? Nothing to do.
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return;
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u64 end = start + size;
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int i;
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for (i=0; i<e820_count; i++) {
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struct e820entry *e = &e820_list[i];
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if (end < e->start)
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// Simple insertion point.
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break;
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u64 e_end = e->start + e->size;
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if (start > e_end)
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// No overlap.
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continue;
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// New item overlaps (or borders) an existing one.
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if (start > e->start) {
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e->size = start - e->start;
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i++;
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if (end < e_end)
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// Need to split existing item
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insert_e820(i, end, e_end - end, e->type);
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if (type == e->type) {
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// Same type - merge them.
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size += start - e->start;
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start = e->start;
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i--;
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remove_e820(i);
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}
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}
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if (type != E820_HOLE) {
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insert_e820(i, start, size, type);
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i++;
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}
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// Remove all existing items that are completely overlapped.
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while (i<e820_count) {
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e = &e820_list[i];
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if (end < e->start)
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// No overlap - done.
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break;
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e_end = e->start + e->size;
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if (end >= e_end) {
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// Existing item completely overlapped - remove it.
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remove_e820(i);
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continue;
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}
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// Not completely overlapped - adjust its start.
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e->start = end;
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e->size = e_end - e->start;
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if (type == e->type) {
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// Same type - merge them.
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(e-1)->size += e->size;
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remove_e820(i);
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}
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break;
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}
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//dump_map();
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return;
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}
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// Just insert item.
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insert_e820(i, start, size, type);
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//dump_map();
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}
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// Symbols defined in romlayout.S
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extern char freespace2_start, freespace2_end;
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u32 bios_table_cur_addr, bios_table_end_addr;
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// Prep for memmap stuff - init bios table locations.
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void
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memmap_setup()
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{
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bios_table_cur_addr = (u32)&freespace2_start;
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bios_table_end_addr = (u32)&freespace2_end;
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dprintf(1, "bios_table_addr: 0x%08x end=0x%08x\n",
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bios_table_cur_addr, bios_table_end_addr);
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bios_table_cur_addr = ALIGN(bios_table_cur_addr, 4);
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u32 msize = CONFIG_MAX_E820 * sizeof(e820_list[0]);
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if (bios_table_cur_addr + msize > bios_table_end_addr) {
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dprintf(1, "No room for e820 map!\n");
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return;
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}
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e820_count = 0;
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e820_list = (void*)bios_table_cur_addr;
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bios_table_cur_addr += msize;
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}
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// Report on final memory locations.
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void
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memmap_finalize()
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{
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dump_map();
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dprintf(1, "final bios_table_addr: 0x%08x (used %d%%)\n"
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, bios_table_cur_addr
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, (100 * (bios_table_cur_addr - (u32)&freespace2_start)
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/ ((u32)&freespace2_end - (u32)&freespace2_start)));
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if (bios_table_cur_addr > bios_table_end_addr)
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BX_PANIC("bios_table_end_addr overflow!\n");
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}
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