cosmopolitan/libc/calls/metalfile.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

75 lines
4.1 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│
╞══════════════════════════════════════════════════════════════════════════════╡
│ This is free and unencumbered software released into the public domain. │
│ │
│ Anyone is free to copy, modify, publish, use, compile, sell, or │
│ distribute this software, either in source code form or as a compiled │
│ binary, for any purpose, commercial or non-commercial, and by any │
│ means. │
│ │
│ In jurisdictions that recognize copyright laws, the author or authors │
│ of this software dedicate any and all copyright interest in the │
│ software to the public domain. We make this dedication for the benefit │
│ of the public at large and to the detriment of our heirs and │
│ successors. We intend this dedication to be an overt act of │
│ relinquishment in perpetuity of all present and future rights to this │
│ software under copyright law. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, │
│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
│ IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR │
│ OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, │
│ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR │
│ OTHER DEALINGS IN THE SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "ape/relocations.h"
#include "ape/sections.internal.h"
#include "libc/assert.h"
#include "libc/calls/internal.h"
#include "libc/calls/metalfile.internal.h"
#include "libc/intrin/directmap.internal.h"
#include "libc/intrin/weaken.h"
#include "libc/macros.internal.h"
#include "libc/mem/mem.h"
#include "libc/runtime/pc.internal.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/at.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/errfuns.h"
#define MAP_ANONYMOUS_linux 0x00000020
#define MAP_FIXED_linux 0x00000010
#define MAP_SHARED_linux 0x00000001
STATIC_YOINK("_init_metalfile");
void *__ape_com_base;
size_t __ape_com_size = 0;
textstartup noasan void InitializeMetalFile(void) {
if (IsMetal()) {
/*
* Copy out a pristine image of the program — before the program might
* decide to modify its own .data section.
*
* This code is included if a symbol "file:/proc/self/exe" is defined
* (see libc/calls/metalfile.internal.h & libc/calls/metalfile_init.S).
* The zipos code will automatically arrange to do this. Alternatively,
* user code can STATIC_YOINK this symbol.
*/
size_t size = ROUNDUP(_ezip - _base, 4096);
void *copied_base;
struct DirectMap dm;
dm = sys_mmap_metal(NULL, size, PROT_READ | PROT_WRITE,
MAP_SHARED_linux | MAP_ANONYMOUS_linux, -1, 0);
copied_base = dm.addr;
_npassert(copied_base != (void *)-1);
memcpy(copied_base, (void *)(BANE + IMAGE_BASE_PHYSICAL), size);
__ape_com_base = copied_base;
__ape_com_size = size;
}
}