Likewise on the x86 branch, we have to remove all virtual memory ranges from the
virtual memory allocator that are used by one-by-one mappings of I/O regions
used by the kernel.
Fix#1797
Add a Platform::setup_irq_mode function which enables the IRQ session to
update the trigger mode and polarity of the associated IRQ according to
the session parameters. On ARM this function is a nop.
This change enables the x86_64 platform to support devices which use
arbitrary trigger modes and polarity settings, e.g. AHCI on QEMU and
real hardware.
Fixes#1528.
Enable a platform to specify how the MMIO memory allocator is to be
initialized. On ARM the existing behavior is kept while on x86 the I/O
memory is defined as the entire address space excluding the core only
RAM regions. This aligns the hw_x86_64 I/O memory allocator
initialization with how it is done for other x86 kernels such as NOVA or
Fiasco.
In order to match the I/O APIC configuration, a request for user timer
IRQ 0 is remapped to vector 50 (Board::TIMER_VECTOR_USER), all other
requests are transposed by adding the vector offset 48
(Board::VECTOR_REMAP_BASE).