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.
All users which relied on the default constructor use a None lock rank
for now. This will make it easier to in the future remove LockRank and
actually annotate the ranks by searching for None.
Unlike Clang, GCC does not support 8-byte atomics on i686 with the
-mno-80387 flag set, so until that is fixed, implement a minimal set of
atomics that are currently required.
As soon as we've saved CR2 (the faulting address), we can re-enable
interrupt processing. This should make the kernel more responsive under
heavy fault loads.
To ensure that we stay on the same CPU that acquired the spinlock until
we're completely unlocked, we now leave the critical section *before*
re-enabling interrupts.
This fixes an issue where we could get preempted after acquiring the
current Processor pointer, but before calling methods on it.
I strongly suspect this was the cause of "Processor::current() == this"
assertion failures.
This makes sure that the debug message are properly aligned when running
the kernel bare-metal on a Raspberry Pi. While we are here, also move
the function out of line.
There's no real value in separating physical pages to supervisor and
user types, so let's remove the concept and just let everyone to use
"user" physical pages which can be allocated from any PhysicalRegion
we want to use. Later on, we will remove the "user" prefix as this
prefix is not needed anymore.
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.
This commit moves the length calculations out to be directly on the
StringView users. This is an important step towards the goal of removing
StringView(char const*), as it moves the responsibility of calculating
the size of the string to the user of the StringView (which will prevent
naive uses causing OOB access).
Access to RDTSC is occasionally restricted to give malware one less
option to accurately time attacks (side-channels, etc.).
However, QEMU requires access to the timestamp counter for the exact
same reason (which is accurately timing its CPU ticks), so lets just
enable it for now.
The RDGSBASE userspace instruction allows programs to read the contents
of the gs segment register which contains a kernel pointer to the base
of the current Processor struct.
Since we don't use this instruction in Serenity at the moment, we can
simply disable it for now to ensure we don't break KASLR. Support can
later be restored once proper swapping of the contents of gs is done on
userspace/kernel boundaries.
This is necessary for the next commit in the patch, otherwise this can't
be compiled. It seems like this was a hidden issue that is discovered
now only by changing includes in a mass-scale.
For an upcoming change to support interrupts in this driver, this class
has to inherit from IRQHandler. That in turn will make this class
virtual, which will then actually call the destructor of the class. We
don't want this to happen, thus we have to wrap the class in a
AK::NeverDestroyed.
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.
This register can be used to check whether the 4 different types of
interrupts are masked. A different variant can be used to set/clear
specific interrupt bits.
This requires us to add an Interrupts.h file in the Kernel/Arch
directory, which includes the architecture specific files.
The commit also stubs out the functions to be able to compile the
aarch64 Kernel.
Including signal.h would cause several ports to fail on build,
because it would end up including AK/Platform.h through these
mcontext headers. This is problematic because AK/Platform.h defines
several macros with very common names, such as `NAKED` (breaks radare2),
and `NO_SANITIZE_ADDRESS` and `ALWAYS_INLINE` (breaks ruby).
When disabling UBSAN, the compiler would complain that the constraints
of the inline assembly could not be met. By adding the alignas specifier
the compiler can now determine that the struct can be passed into a
register, and thus the constraints are met.
This adds some new buffers to the `FPUState` struct, which contains
enough space for the `xsave` instruction to run. This instruction writes
the upper part of the x86 SIMD registers (YMM0-15) to a seperate
256-byte area, as well as an "xsave header" describing the region.
If the underlying processor supports AVX, the `fxsave` instruction is no
longer used, as `xsave` itself implictly saves all of the SSE and x87
registers.
Co-authored-by: Leon Albrecht <leon.a@serenityos.org>
