* [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>
- use PAGE_RSRV bit (originally only for blinkenlights),
rather than PAGE_V bit, to indicate that a virtual address
page has been reserved — this should allow a program to
create & reserve inaccessible "guard pages"
- mark page table entries for non-code pages with PAGE_XD bit,
which should be supported on (circa) post-2004 x86-64 CPUs
- Polyfill ucontext_t on FreeBSD/OpenBSD/NetBSD
- Add tests confirming signals can edit CPU state
- Work towards supporting ZIP filesystem on bare metal
- Add more tinymath unit tests for POSIX conformance
- Add X87 and SSE status flags to crash report
- Fix some bugs in blinkenlights
- Fix llvm build breakage
Your Actually Portable Executables now contains a simple virtual memory
that works similarly to the Linux Kernel in the sense that it maps your
physical memory to negative addresses. This is needed to support mmap()
and malloc(). This functionality has zero code size impact. For example
the MODE=tiny LIFE.COM executable is still only 12KB in size.
The APE bootloader code has also been simplified to improve readibility
and further elevate the elegance by which we're able to support so many
platforms thereby enhancing verifiability so that we may engender trust
in this bootloading process.
