cosmopolitan/libc/intrin/directmap-metal.c
tkchia 0da47c51de
[metal] Allow programs larger than 440 KiB to run in bare metal mode (#685)
* [metal] Copy program pages to extended memory at startup
* [metal] Reclaim base memory pages for later app use
* [metal] Load program pages beyond 1st 440 KiB to extended memory

o//examples/hellolua.com now runs correctly under QEMU (in
legacy BIOS mode).

* [metal] Place GDT in read/write segment

The CPU absolutely needs to alter the GDT when loading the
task register (via ltr).  To account for this, I move the
GDT into a read/write data section.  There is still a "rump"
read-only GDT in the text section that is used by the real
mode bootloader.

We also delay the loading of the task register (ltr) until
after the IDT and TSS are finally set up.

* [metal] Get examples/vga2.c serial output working for UEFI boot
* [metal] Get examples/vga2.c VGA output working for UEFI boot
* [metal] Allow munmap() to reclaim dynamically allocated pages
* Place TLS sections right after .text, not after embedded zip file

Co-authored-by: tkchia <tkchia-cosmo@gmx.com>
2022-12-17 17:51:20 -08:00

111 lines
4.6 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 2021 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/calls/calls.h"
#include "libc/intrin/directmap.internal.h"
#include "libc/calls/internal.h"
#include "libc/calls/metalfile.internal.h"
#include "libc/macros.internal.h"
#include "libc/runtime/pc.internal.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/errfuns.h"
#define MAP_ANONYMOUS_linux 0x00000020
#define MAP_FIXED_linux 0x00000010
static uint64_t sys_mmap_metal_break;
noasan static struct DirectMap bad_mmap(void) {
struct DirectMap res;
res.addr = (void *)-1;
res.maphandle = -1;
return res;
}
noasan struct DirectMap sys_mmap_metal(void *vaddr, size_t size, int prot,
int flags, int fd, int64_t off) {
/* asan runtime depends on this function */
size_t i;
struct mman *mm;
struct DirectMap res;
uint64_t addr, faddr = 0, page, e, *pte, *fdpte, *pml4t;
mm = (struct mman *)(BANE + 0x0500);
pml4t = __get_pml4t();
size = ROUNDUP(size, 4096);
addr = (uint64_t)vaddr;
if (!(flags & MAP_ANONYMOUS_linux)) {
struct Fd *sfd;
struct MetalFile *file;
if (off < 0 || fd < 0 || fd >= g_fds.n) return bad_mmap();
sfd = &g_fds.p[fd];
if (sfd->kind != kFdFile) return bad_mmap();
file = (struct MetalFile *)sfd->handle;
/* TODO: allow mapping partial page at end of file, if file size not
* multiple of page size */
if (off > file->size || size > file->size - off) return bad_mmap();
faddr = (uint64_t)file->base + off;
if (faddr % 4096 != 0) return bad_mmap();
}
if (!(flags & MAP_FIXED_linux)) {
if (!addr) {
addr = 4096;
} else {
addr = ROUNDUP(addr, 4096);
}
for (i = 0; i < size; i += 4096) {
pte = __get_virtual(mm, pml4t, addr + i, false);
if (pte && (*pte & (PAGE_V | PAGE_RSRV))) {
addr = MAX(addr, sys_mmap_metal_break) + i + 4096;
i = 0;
}
}
sys_mmap_metal_break = MAX(addr + size, sys_mmap_metal_break);
}
for (i = 0; i < size; i += 4096) {
pte = __get_virtual(mm, pml4t, addr + i, true);
if (pte) {
if ((flags & MAP_ANONYMOUS_linux)) {
page = __new_page(mm);
if (!page) return bad_mmap();
__clear_page(BANE + page);
e = page | PAGE_RSRV | PAGE_U;
if ((prot & PROT_WRITE))
e |= PAGE_V | PAGE_RW;
else if ((prot & (PROT_READ | PROT_EXEC)))
e |= PAGE_V;
if (!(prot & PROT_EXEC)) e |= PAGE_XD;
} else {
fdpte = __get_virtual(mm, pml4t, faddr + i, false);
e = *fdpte | PAGE_RSRV | PAGE_U;
page = e & PAGE_TA;
if (!(prot & PROT_WRITE)) e &= ~PAGE_RW;
if (!(prot & PROT_EXEC)) e |= PAGE_XD;
}
__ref_page(mm, pml4t, page);
*pte = e;
invlpg(addr + i);
} else {
addr = -1;
break;
}
}
res.addr = (void *)addr;
res.maphandle = -1;
return res;
}