mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 19:43:32 +00:00
2d80bbc802
blinkenlights now does a pretty good job emulating what happens when binaries boot from BIOS into long mode. So it's been much easier to debug the bare metal process and wrinkle out many issues.
285 lines
8.6 KiB
C
285 lines
8.6 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/assert.h"
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#include "libc/log/check.h"
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#include "libc/log/log.h"
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#include "libc/macros.h"
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#include "libc/mem/mem.h"
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#include "libc/str/str.h"
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#include "libc/x/x.h"
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#include "tool/build/lib/endian.h"
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#include "tool/build/lib/machine.h"
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#include "tool/build/lib/memory.h"
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#include "tool/build/lib/pml4t.h"
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#include "tool/build/lib/stats.h"
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#include "tool/build/lib/throw.h"
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void SetReadAddr(struct Machine *m, int64_t addr, uint32_t size) {
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if (size) {
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m->readaddr = addr;
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m->readsize = size;
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}
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}
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void SetWriteAddr(struct Machine *m, int64_t addr, uint32_t size) {
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if (size) {
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m->writeaddr = addr;
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m->writesize = size;
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}
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}
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long HandlePageFault(struct Machine *m, uint64_t entry, uint64_t table,
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unsigned index) {
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long page;
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if ((page = AllocateLinearPage(m)) != -1) {
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--m->memstat.reserved;
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*(uint64_t *)(m->real.p + table + index * 8) =
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page | entry & ~0x7ffffffffe00;
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}
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return page;
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}
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void *FindReal(struct Machine *m, int64_t virt) {
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long page;
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uint64_t table, entry;
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unsigned skew, level, index, i;
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if ((m->mode & 3) != XED_MODE_REAL) {
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if (-0x800000000000 <= virt && virt < 0x800000000000) {
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skew = virt & 0xfff;
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virt &= -0x1000;
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for (i = 0; i < ARRAYLEN(m->tlb); ++i) {
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if (m->tlb[i].virt == virt && m->tlb[i].host) {
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return m->tlb[i].host + skew;
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}
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}
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level = 39;
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entry = m->cr3;
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do {
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table = entry & 0x7ffffffff000;
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CHECK_LT(table, m->real.n);
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index = (virt >> level) & 511;
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entry = *(uint64_t *)(m->real.p + table + index * 8);
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if (!(entry & 1)) return NULL;
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} while ((level -= 9) >= 12);
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if (!(entry & 0x0e00)) {
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page = entry & 0x7ffffffff000;
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CHECK_LT(page, m->real.n);
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} else if ((page = HandlePageFault(m, entry, table, index)) == -1) {
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return NULL;
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}
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m->tlbindex = (m->tlbindex + 1) & (ARRAYLEN(m->tlb) - 1);
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m->tlb[m->tlbindex] = m->tlb[0];
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m->tlb[0].virt = virt;
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m->tlb[0].host = m->real.p + page;
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return m->real.p + page + skew;
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} else {
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return NULL;
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}
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} else if (0 <= virt && virt + 0xfff < m->real.n) {
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return m->real.p + virt;
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} else {
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return NULL;
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}
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}
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void *ResolveAddress(struct Machine *m, int64_t v) {
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void *r;
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if ((r = FindReal(m, v))) return r;
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ThrowSegmentationFault(m, v);
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}
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void VirtualSet(struct Machine *m, int64_t v, char c, uint64_t n) {
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char *p;
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uint64_t k;
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k = 0x1000 - (v & 0xfff);
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while (n) {
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k = MIN(k, n);
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p = ResolveAddress(m, v);
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memset(p, c, k);
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n -= k;
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v += k;
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k = 0x1000;
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}
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}
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void VirtualCopy(struct Machine *m, int64_t v, char *r, uint64_t n, bool d) {
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char *p;
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uint64_t k;
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k = 0x1000 - (v & 0xfff);
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while (n) {
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k = MIN(k, n);
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p = ResolveAddress(m, v);
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if (d) {
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memcpy(r, p, k);
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} else {
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memcpy(p, r, k);
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}
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n -= k;
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r += k;
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v += k;
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k = 0x1000;
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}
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}
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void *VirtualSend(struct Machine *m, void *dst, int64_t src, uint64_t n) {
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VirtualCopy(m, src, dst, n, true);
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return dst;
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}
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void VirtualSendRead(struct Machine *m, void *dst, int64_t addr, uint64_t n) {
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VirtualSend(m, dst, addr, n);
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SetReadAddr(m, addr, n);
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}
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void VirtualRecv(struct Machine *m, int64_t dst, void *src, uint64_t n) {
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VirtualCopy(m, dst, src, n, false);
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}
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void VirtualRecvWrite(struct Machine *m, int64_t addr, void *src, uint64_t n) {
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VirtualRecv(m, addr, src, n);
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SetWriteAddr(m, addr, n);
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}
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void *ReserveAddress(struct Machine *m, int64_t v, size_t n) {
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void *r;
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DCHECK_LE(n, sizeof(m->stash));
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if ((v & 0xfff) + n <= 0x1000) return ResolveAddress(m, v);
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m->stashaddr = v;
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m->stashsize = n;
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r = m->stash;
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VirtualSend(m, r, v, n);
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return r;
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}
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void *AccessRam(struct Machine *m, int64_t v, size_t n, void *p[2],
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uint8_t tmp[n], bool copy) {
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unsigned k;
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uint8_t *a, *b;
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DCHECK_LE(n, 0x1000);
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if ((v & 0xfff) + n <= 0x1000) return ResolveAddress(m, v);
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k = 0x1000;
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k -= v & 0xfff;
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DCHECK_LE(k, 0x1000);
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a = ResolveAddress(m, v);
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b = ResolveAddress(m, v + k);
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if (copy) {
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memcpy(tmp, a, k);
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memcpy(tmp + k, b, n - k);
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}
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p[0] = a;
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p[1] = b;
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return tmp;
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}
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void *Load(struct Machine *m, int64_t v, size_t n, uint8_t b[n]) {
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void *p[2];
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SetReadAddr(m, v, n);
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return AccessRam(m, v, n, p, b, true);
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}
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void *BeginStore(struct Machine *m, int64_t v, size_t n, void *p[2],
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uint8_t b[n]) {
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SetWriteAddr(m, v, n);
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return AccessRam(m, v, n, p, b, false);
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}
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void *BeginStoreNp(struct Machine *m, int64_t v, size_t n, void *p[2],
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uint8_t b[n]) {
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if (!v) return NULL;
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return BeginStore(m, v, n, p, b);
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}
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void *BeginLoadStore(struct Machine *m, int64_t v, size_t n, void *p[2],
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uint8_t b[n]) {
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SetWriteAddr(m, v, n);
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return AccessRam(m, v, n, p, b, true);
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}
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void EndStore(struct Machine *m, int64_t v, size_t n, void *p[2],
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uint8_t b[n]) {
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uint8_t *a;
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unsigned k;
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DCHECK_LE(n, 0x1000);
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if ((v & 0xfff) + n <= 0x1000) return;
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k = 0x1000;
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k -= v & 0xfff;
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DCHECK_GT(k, n);
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DCHECK_NOTNULL(p[0]);
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DCHECK_NOTNULL(p[1]);
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memcpy(p[0], b, k);
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memcpy(p[1], b + k, n - k);
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}
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void EndStoreNp(struct Machine *m, int64_t v, size_t n, void *p[2],
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uint8_t b[n]) {
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if (v) EndStore(m, v, n, p, b);
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}
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void *LoadStr(struct Machine *m, int64_t addr) {
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size_t have;
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char *copy, *page, *p;
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have = 0x1000 - (addr & 0xfff);
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if (!addr) return NULL;
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if (!(page = FindReal(m, addr))) return NULL;
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if ((p = memchr(page, '\0', have))) {
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SetReadAddr(m, addr, p - page + 1);
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return page;
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}
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CHECK_LT(m->freelist.i, ARRAYLEN(m->freelist.p));
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if (!(copy = malloc(have + 0x1000))) return NULL;
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memcpy(copy, page, have);
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for (;;) {
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if (!(page = FindReal(m, addr + have))) break;
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if ((p = memccpy(copy + have, page, '\0', 0x1000))) {
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SetReadAddr(m, addr, have + (p - (copy + have)) + 1);
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return (m->freelist.p[m->freelist.i++] = copy);
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}
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have += 0x1000;
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if (!(p = realloc(copy, have + 0x1000))) break;
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copy = p;
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}
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free(copy);
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return NULL;
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}
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void *LoadBuf(struct Machine *m, int64_t addr, size_t size) {
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size_t have, need;
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char *buf, *copy, *page;
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have = 0x1000 - (addr & 0xfff);
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if (!addr) return NULL;
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if (!(buf = FindReal(m, addr))) return NULL;
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if (size > have) {
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CHECK_LT(m->freelist.i, ARRAYLEN(m->freelist.p));
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if (!(copy = malloc(size))) return NULL;
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buf = memcpy(copy, buf, have);
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do {
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need = MIN(0x1000, size - have);
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if ((page = FindReal(m, addr + have))) {
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memcpy(copy + have, page, need);
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have += need;
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} else {
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free(copy);
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return NULL;
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}
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} while (have < size);
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}
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SetReadAddr(m, addr, size);
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return buf;
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}
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