Fix metal bugs so deathstar.com runs in qemu (#20)

- Remove XD bit in page tables
- Fix cylinder+head+sector arithmetic
- Implement fstat() for serial file descriptors on metal

Here's how to boot an Actually Portable Executable in QEMU:

    make -j12 o//tool/viz/deathstar.com
    qemu-system-x86_64 -serial stdio -fda o//tool/viz/deathstar.com

Here's a screenshot of DEATHSTAR.COM booted in QEMU:
https://justine.lol/cosmopolitan/cosmo-metal-qemu.png

Thus metal support is in much better shape now, but still incomplete.
Only a few system calls have been polyfilled. To figure out which ones
your program needs, simply boot it in the blinkenlights emulator with a
breakpoint, and press CTRL-C to continue to the system call breakpoint.
If it doesn't break then you should be good. (Note: to emulate normally
you can press 'c' and use CTRL-T and ALT-T to tune the speed.)

    m=tiny
    make -j12 SILENT=0 MODE=$m          \
      o/$m/tool/build/blinkenlights.com \
      o/$m/tool/viz/deathstar.com
    o/$m/tool/build/blinkenlights.com   \
      -r -t -b systemfive.linux         \
      o/$m/tool/viz/deathstar.com

Thank @Theldus for the bug report that made this change possible.
Fixes #20 which explains this change further.
This commit is contained in:
Justine Tunney 2021-01-16 17:52:15 -08:00
parent 58d9659d53
commit f0600a898c
13 changed files with 182 additions and 119 deletions

View file

@ -27,10 +27,14 @@
int nanosleep(const struct timespec *req, struct timespec *rem) {
if (!req) return efault();
if (!IsWindows()) {
if (!IsXnu()) {
return nanosleep$sysv(req, rem);
if (!IsMetal()) {
if (!IsXnu()) {
return nanosleep$sysv(req, rem);
} else {
return nanosleep$xnu(req, rem);
}
} else {
return nanosleep$xnu(req, rem);
return enosys(); /* TODO: Sleep on Metal */
}
} else {
return nanosleep$nt(req, rem);