60 lines
3.2 KiB
C
60 lines
3.2 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
|
|
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
|
|
╞══════════════════════════════════════════════════════════════════════════════╡
|
|
│ Copyright 2020 Justine Alexandra Roberts Tunney │
|
|
│ │
|
|
│ This program is free software; you can redistribute it and/or modify │
|
|
│ it under the terms of the GNU General Public License as published by │
|
|
│ the Free Software Foundation; version 2 of the License. │
|
|
│ │
|
|
│ This program is distributed in the hope that it will be useful, but │
|
|
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
|
|
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
|
|
│ General Public License for more details. │
|
|
│ │
|
|
│ You should have received a copy of the GNU General Public License │
|
|
│ along with this program; if not, write to the Free Software │
|
|
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
|
|
│ 02110-1301 USA │
|
|
╚─────────────────────────────────────────────────────────────────────────────*/
|
|
#include "ape/config.h"
|
|
#include "ape/lib/pc.h"
|
|
#include "libc/bits/bits.h"
|
|
#include "libc/bits/safemacros.h"
|
|
|
|
/**
|
|
* Virtualizes physical memory.
|
|
*
|
|
* This function removes memory holes (discovered by e820() earlier) and
|
|
* creates the illusion of flat contiguous memory for as much RAM as the
|
|
* BIOS reports usable. Memory is safe to use and remap afterwards.
|
|
*
|
|
* @see ape/ape.S
|
|
*/
|
|
textreal void flattenhighmemory(struct SmapEntry *e820, struct PageTable *pml4t,
|
|
uint64_t *ptsp) {
|
|
struct SmapEntry *smap = e820;
|
|
struct SmapEntry *hole = e820;
|
|
uint64_t paddr = IMAGE_BASE_PHYSICAL;
|
|
uint64_t vaddr = IMAGE_BASE_VIRTUAL;
|
|
while (smap->size) {
|
|
while (smap->size && smap->type != kMemoryUsable) smap++;
|
|
paddr = roundup(max(paddr, smap->addr), PAGESIZE);
|
|
while (paddr < rounddown(smap->addr + smap->size, PAGESIZE)) {
|
|
while (hole->size &&
|
|
(hole->type == kMemoryUsable || hole->addr + hole->size < paddr)) {
|
|
hole++;
|
|
}
|
|
if (paddr >= hole->addr && paddr < hole->addr + hole->size) {
|
|
paddr = roundup(hole->addr + hole->size, PAGESIZE);
|
|
} else {
|
|
uint64_t *entry = getpagetableentry(vaddr, 3, pml4t, ptsp);
|
|
*entry = paddr | PAGE_V | PAGE_RW;
|
|
vaddr += 0x1000;
|
|
paddr += 0x1000;
|
|
}
|
|
}
|
|
smap++;
|
|
}
|
|
}
|