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[metal] Allow programs larger than 440 KiB to run in bare metal mode (#685)

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* [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>
This commit is contained in:
tkchia 2022-12-18 09:51:20 +08:00 • committed by GitHub
parent 120079b0a6
commit 0da47c51de
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GPG key ID: 4AEE18F83AFDEB23
16 changed files with 725 additions and 191 deletions
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22
libc/intrin/directmap-metal.c
View file

@ -44,7 +44,7 @@ noasan struct DirectMap sys_mmap_metal(void *vaddr, size_t size, int prot,
size_t i;
struct mman *mm;
struct DirectMap res;
uint64_t addr, faddr = 0, page, *pte, *fdpte, *pml4t;
uint64_t addr, faddr = 0, page, e, *pte, *fdpte, *pml4t;
mm = (struct mman *)(BANE + 0x0500);
pml4t = __get_pml4t();
size = ROUNDUP(size, 4096);
@ -78,27 +78,27 @@ noasan struct DirectMap sys_mmap_metal(void *vaddr, size_t size, int prot,
sys_mmap_metal_break = MAX(addr + size, sys_mmap_metal_break);
}
for (i = 0; i < size; i += 4096) {
page = __new_page(mm);
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);
page |= PAGE_RSRV | PAGE_U;
e = page | PAGE_RSRV | PAGE_U;
if ((prot & PROT_WRITE))
page |= PAGE_V | PAGE_RW;
e |= PAGE_V | PAGE_RW;
else if ((prot & (PROT_READ | PROT_EXEC)))
page |= PAGE_V;
if (!(prot & PROT_EXEC)) page |= PAGE_XD;
e |= PAGE_V;
if (!(prot & PROT_EXEC)) e |= PAGE_XD;
} else {
fdpte = __get_virtual(mm, pml4t, faddr + i, false);
page = *fdpte;
page |= PAGE_RSRV | PAGE_U;
if (!(prot & PROT_WRITE)) page &= ~PAGE_RW;
if (!(prot & PROT_EXEC)) page |= PAGE_XD;
e = *fdpte | PAGE_RSRV | PAGE_U;
page = e & PAGE_TA;
if (!(prot & PROT_WRITE)) e &= ~PAGE_RW;
if (!(prot & PROT_EXEC)) e |= PAGE_XD;
}
*pte = page;
__ref_page(mm, pml4t, page);
*pte = e;
invlpg(addr + i);
} else {
addr = -1;