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// Support for building memory maps suitable for int 15 e820 calls.
//
// Copyright (C) 2008,2009 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU LGPLv3 license.
#include "config.h" // BUILD_MAX_E820
#include "e820map.h" // struct e820entry
#include "output.h" // dprintf
#include "string.h" // memmove
/****************************************************************
* e820 memory map
****************************************************************/
// Info on e820 map location and size.
struct e820entry e820_list[BUILD_MAX_E820] VARFSEG;
int e820_count VARFSEG;
// Remove an entry from the e820_list.
static void
remove_e820(int i)
{
e820_count--;
memmove(&e820_list[i], &e820_list[i+1]
, sizeof(e820_list[0]) * (e820_count - i));
}
// Insert an entry in the e820_list at the given position.
static void
insert_e820(int i, u64 start, u64 size, u32 type)
{
if (e820_count >= BUILD_MAX_E820) {
warn_noalloc();
return;
}
memmove(&e820_list[i+1], &e820_list[i]
, sizeof(e820_list[0]) * (e820_count - i));
e820_count++;
struct e820entry *e = &e820_list[i];
e->start = start;
e->size = size;
e->type = type;
}
static const char *
e820_type_name(u32 type)
{
switch (type) {
case E820_RAM: return "RAM";
case E820_RESERVED: return "RESERVED";
case E820_ACPI: return "ACPI";
case E820_NVS: return "NVS";
case E820_UNUSABLE: return "UNUSABLE";
default: return "UNKNOWN";
}
}
// Show the current e820_list.
static void
dump_map(void)
{
dprintf(1, "e820 map has %d items:\n", e820_count);
int i;
for (i=0; i<e820_count; i++) {
struct e820entry *e = &e820_list[i];
u64 e_end = e->start + e->size;
dprintf(1, " %d: %016llx - %016llx = %d %s\n", i
, e->start, e_end, e->type, e820_type_name(e->type));
}
}
#define E820_HOLE ((u32)-1) // Used internally to remove entries
// Add a new entry to the list. This scans for overlaps and keeps the
// list sorted.
void
e820_add(u64 start, u64 size, u32 type)
{
dprintf(8, "Add to e820 map: %08llx %08llx %d\n", start, size, type);
if (! size)
// Huh? Nothing to do.
return;
// Find position of new item (splitting existing item if needed).
u64 end = start + size;
int i;
for (i=0; i<e820_count; i++) {
struct e820entry *e = &e820_list[i];
u64 e_end = e->start + e->size;
if (start > e_end)
continue;
// Found position - check if an existing item needs to be split.
if (start > e->start) {
if (type == e->type) {
// Same type - merge them.
size += start - e->start;
start = e->start;
} else {
// Split existing item.
e->size = start - e->start;
i++;
if (e_end > end)
insert_e820(i, end, e_end - end, e->type);
}
}
break;
}
// Remove/adjust existing items that are overlapping.
while (i<e820_count) {
struct e820entry *e = &e820_list[i];
if (end < e->start)
// No overlap - done.
break;
u64 e_end = e->start + e->size;
if (end >= e_end) {
// Existing item completely overlapped - remove it.
remove_e820(i);
continue;
}
// Not completely overlapped - adjust its start.
e->start = end;
e->size = e_end - end;
if (type == e->type) {
// Same type - merge them.
size += e->size;
remove_e820(i);
}
break;
}
// Insert new item.
if (type != E820_HOLE)
insert_e820(i, start, size, type);
//dump_map();
}
// Remove any definitions in a memory range (make a memory hole).
void
e820_remove(u64 start, u64 size)
{
e820_add(start, size, E820_HOLE);
}
// Report on final memory locations.
void
e820_prepboot(void)
{
dump_map();
}
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