This sets up the RPi::Timer to trigger an interurpt every 4ms using one
of the comparators. The actual time is calculated by looking at the main
counter of the RPi::Timer using the Timer::update_time function.
A stub for Scheduler::timer_tick is also added, since the TimeManagement
code now calls the function.
The APICTimer, HPET and RTC (the RTC timer is in the context of the PC
RTC here) are timers that exist only in x86 platforms, therefore, we
move the handling code and the initialization code to the Arch/x86/Time
directory. Other related code patterns in the TimeManagement singleton
and in the Random.cpp file are guarded with #ifdef to ensure they are
only compiled for x86 builds.
The PIC and APIC code are specific to x86 platforms, so move them out of
the general Interrupts directory to Arch/x86/common/Interrupts directory
instead.
The RTC and CMOS are currently only supported for x86 platforms and use
specific x86 instructions to produce only certain x86 plaform operations
and results, therefore, we move them to the Arch/x86 specific directory.
Until now, our kernel has reimplemented a number of AK classes to
provide automatic internal locking:
- RefPtr
- NonnullRefPtr
- WeakPtr
- Weakable
This patch renames the Kernel classes so that they can coexist with
the original AK classes:
- RefPtr => LockRefPtr
- NonnullRefPtr => NonnullLockRefPtr
- WeakPtr => LockWeakPtr
- Weakable => LockWeakable
The goal here is to eventually get rid of the Lock* classes in favor of
using external locking.
Instead of having two separate implementations of AK::RefCounted, one
for userspace and one for kernelspace, there is now RefCounted and
AtomicRefCounted.
While null StringViews are just as bad, these prevent the removal of
StringView(char const*) as that constructor accepts a nullptr.
No functional changes.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
These 2 classes currently contain much code that is x86(_64) specific.
Move them to the architecture specific directory. This also allows for a
simpler implementation for aarch64.
We were unconditionally trying to update it in the interrupt, which
would depend on the timer interrupt not being received too soon after
the timers are initialized (before the time page was initialized),
which was the case when using HPET timers via the ACPI tables, but not
when using the PIT when ACPI was disabled.
This mostly just moved the problem, as a lot of the callers are not
capable of propagating the errors themselves, but it's a step in the
right direction.
This was a premature optimization from the early days of SerenityOS.
The eternal heap was a simple bump pointer allocator over a static
byte array. My original idea was to avoid heap fragmentation and improve
data locality, but both ideas were rooted in cargo culting, not data.
We would reserve 4 MiB at boot and only ended up using ~256 KiB, wasting
the rest.
This patch replaces all kmalloc_eternal() usage by regular kmalloc().
Currently the APIC class is constructed irrespective of whether it
is used or not.
So, move APIC initialization from init to the InterruptManagement
class and construct the APIC class only when it is needed.
We now use AK::Error and AK::ErrorOr<T> in both kernel and userspace!
This was a slightly tedious refactoring that took a long time, so it's
not unlikely that some bugs crept in.
Nevertheless, it does pass basic functionality testing, and it's just
real nice to finally see the same pattern in all contexts. :^)
A new RegisterState header includes the platform specific RegisterState
header based on the platform being compiled.
The Aarch64 RegisterState header contains stubs for Debug
Previously there was a mix of returning plain strings and returning
explicit string views using `operator ""sv`. This change switches them
all to standardized on `operator ""sv` as it avoids a call to strlen.
This will somwhat help unify them also under the same SysFS directory in
the commit.
Also, it feels much more like this change reflects the reality that both
ACPI and the BIOS are part of the firmware on x86 computers.
This expands the reach of error propagation greatly throughout the
kernel. Sadly, it also exposes the fact that we're allocating (and
doing other fallible things) in constructors all over the place.
This patch doesn't attempt to address that of course. That's work for
our future selves.
This commit moves the KResult and KResultOr objects to Kernel/API to
signify that they may now be freely used by userspace code at points
where a syscall-related error result is to be expected. It also exposes
KResult and KResultOr to the global namespace to make it nicer to use
for userspace code.
As pointed out by 8infy, this mechanism is racy:
WRITER:
1. ++update1;
2. write_data();
3. ++update2;
READER:
1. do { auto saved = update1;
2. read_data();
3. } while (saved != update2);
The following sequence can lead to a bogus/partial read:
R1 R2 R3
W1 W2 W3
We close this race by incrementing the second update counter first:
WRITER:
1. ++update2;
2. write_data();
3. ++update1;
This patch adds a vDSO-like mechanism for exposing the current time as
an array of per-clock-source timestamps.
LibC's clock_gettime() calls sys$map_time_page() to map the kernel's
"time page" into the process address space (at a random address, ofc.)
This is only done on first call, and from then on the timestamps are
fetched from the time page.
This first patch only adds support for CLOCK_REALTIME, but eventually
we should be able to support all clock sources this way and get rid of
sys$clock_gettime() in the kernel entirely. :^)
Accesses are synchronized using two atomic integers that are incremented
at the start and finish of the kernel's time page update cycle.
This switches tracking CPU usage to more accurately measure time in
user and kernel land using either the TSC or another time source.
This will also come in handy when implementing a tickless kernel mode.
