Previously we assumed all hosts would have support for IA32_EFER.NXE.
This is mostly true for newer hardware, but older hardware will crash
and burn if you try to use this feature.
Now we check for support via CPUID.80000001[20].
Use a pthread_cond_t to have the ASMixer thread wait until a client has
connected and added a buffer queue to the "pending mixing" vector.
This solves the long-standing issue of the system "idling" at ~8% CPU.
This patch implements a simple version of the futex (fast userspace
mutex) API in the kernel and uses it to make the pthread_cond_t API's
block instead of busily sched_yield().
An arbitrary userspace address is passed to the kernel as a "token"
that identifies the futex and you can then FUTEX_WAIT and FUTEX_WAKE
that specific userspace address.
FUTEX_WAIT corresponds to pthread_cond_wait() and FUTEX_WAKE is used
for pthread_cond_signal() and pthread_cond_broadcast().
I'm pretty sure I'm missing something in this implementation, but it's
hopefully okay for a start. :^)
Make sure we always line up the "hole" in the progress bar with the
right side of the paint rect. This fixes a 1px wide glitch seen when
using a darker system theme.
Introduce one more (CPU) indirection layer in the paging code: the page
directory pointer table (PDPT). Each PageDirectory now has 4 separate
PageDirectoryEntry arrays, governing 1 GB of VM each.
A really neat side-effect of this is that we can now share the physical
page containing the >=3GB kernel-only address space metadata between
all processes, instead of lazily cloning it on page faults.
This will give us access to the NX (No eXecute) bit, allowing us to
prevent execution of memory that's not supposed to be executed.
If a program's compilation depends on something generated by a library,
we need to make sure that library is built before any of the program's
own compilation units.
Instead of directly manipulating LDFLAGS, set LIB_DEPS in each
subdirectory Makefile listing the libraries needed for
building/linking such as "LIB_DEPS = Core GUI Draw IPC Core".
This adds each library as an -L and -l argument in LDFLAGS, but
also adds the library.a file as a link dependency on the current
$(PROGRAM). This causes the given library to be (re)built before
linking the current $(PROGRAM), but will also re-link any binaries
depending on that library when it is modified, when running make
from the root directory.
Also turn generator tools like IPCCompiler into dependencies on the
files they generate, so they are built on-demand when a particular
directory needs them.
This all allows the root Makefile to just list directories and not
care about the order, as all of the dependency tracking will figure
it out.
I'm not sure how I managed to misread the location of this bit twice.
But I did! Here is finally the correct value, according to Intel:
"Page Global Enable (bit 7 of CR4)"
Jeez! :^)
Cautiously use 5 as a limit for now so that we don't blow the stack.
This can be increased in the future if we are sure that we won't be
blowing the stack, or if the implementation is changed to not use
recursion :^)
GApplication now has a palette. This palette contains all the system
theme colors by default, and is inherited by a new top-level GWidget.
New child widgets inherit their parents palette.
It is possible to override the GApplication palette, and the palette
of any GWidget.
The Palette object contains a bunch of colors, each corresponding to
a ColorRole. Each role has a convenience getter as well.
Each GWidget now has a background_role() and foreground_role(), which
are then looked up in their current palette when painting. This means
that you no longer alter the background color of a widget by setting
it directly, rather you alter either its background role, or the
widget's palette.
