Initializing the variable this way fixes a kernel panic in Clang where
the object was zero-initialized, so the `m_in_scheduler` contained the
wrong value. GCC got it right, but we're better off making this change,
as leaving uninitialized fields in constant-initialized objects can
cause other weird situations like this. Also, initializing only a single
field to a non-zero value isn't worth the cost of no longer fitting in
`.bss`.
Another two variables suffer from the same problem, even though their
values are supposed to be zero. Removing these causes the
`_GLOBAL_sub_I_` function to no longer be generated and the (not
handled) `.init_array` section to be omitted.
This avoids a race between getting the processor-specific SchedulerData
and accessing it. (Switching to a different CPU in that window means
that we're operating on the wrong SchedulerData.)
Co-authored-by: Tom <tomut@yahoo.com>
Leave interrupts enabled so that we can still process IRQs. Critical
sections should only prevent preemption by another thread.
Co-authored-by: Tom <tomut@yahoo.com>
By making these functions static we close a window where we could get
preempted after calling Processor::current() and move to another
processor.
Co-authored-by: Tom <tomut@yahoo.com>
Processing SMP messages outside of non-SMP mode is a waste of time,
and now that we don't rely on the side effects of calling the message
processing function, let's stop calling it entirely. :^)
To add a new per-CPU data structure, add an ID for it to the
ProcessorSpecificDataID enum.
Then call ProcessorSpecific<T>::initialize() when you are ready to
construct the per-CPU data structure on the current CPU. It can then
be accessed via ProcessorSpecific<T>::get().
This patch replaces the existing hard-coded mechanisms for Scheduler
and MemoryManager per-CPU data structure.
Right now we're using the FS segment for our per-CPU struct. On x86_64
there's an instruction to switch between a kernel and usermode GS
segment (swapgs) which we could use.
This patch doesn't update the rest of the code to use swapgs but it
prepares for that by using the GS segment instead of the FS segment.
This adds just enough stubs to make the kernel compile on x86_64. Obviously
it won't do anything useful - in fact it won't even attempt to boot because
Multiboot doesn't support ELF64 binaries - but it gets those compiler errors
out of the way so more progress can be made getting all the missing
functionality in place.
