cosmopolitan/tool/build/lib/pml4t.c

63 lines
3.3 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 │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/alg/arraylist2.internal.h"
#include "tool/build/lib/endian.h"
#include "tool/build/lib/machine.h"
#include "tool/build/lib/pml4t.h"
static void AppendContiguousMemoryRange(struct ContiguousMemoryRanges *ranges,
int64_t a, int64_t b) {
APPEND(&ranges->p, &ranges->i, &ranges->n,
(&(struct ContiguousMemoryRange){a, b}));
}
static void FindContiguousMemoryRangesImpl(
struct Machine *m, struct ContiguousMemoryRanges *ranges, int64_t addr,
unsigned level, int64_t pt, int64_t a, int64_t b) {
int64_t i, page, entry;
for (i = a; i < b; ++i) {
entry = Read64(m->real.p + pt + i * 8);
if (!(entry & 1)) continue;
entry &= 0x7ffffffff000;
page = (addr | i << level) << 16 >> 16;
if (level == 12) {
if (ranges->i && page == ranges->p[ranges->i - 1].b) {
ranges->p[ranges->i - 1].b += 0x1000;
} else {
AppendContiguousMemoryRange(ranges, page, page + 0x1000);
}
} else if (entry + 512 * 8 <= m->real.n) {
FindContiguousMemoryRangesImpl(m, ranges, page, level - 9, entry, 0, 512);
}
}
}
void FindContiguousMemoryRanges(struct Machine *m,
struct ContiguousMemoryRanges *ranges) {
uint64_t cr3;
ranges->i = 0;
if ((m->mode & 3) == XED_MODE_LONG) {
cr3 = m->cr3 & 0x7ffffffff000;
FindContiguousMemoryRangesImpl(m, ranges, 0, 39, cr3, 256, 512);
FindContiguousMemoryRangesImpl(m, ranges, 0, 39, cr3, 0, 256);
} else {
AppendContiguousMemoryRange(ranges, 0, m->real.n);
}
}