This subtraction is necessary to ensure that the section has the correct
address. Also, without this change, the Kernel ELF binary would explode
in size. This was forgotten in a0dd6ec6b1.
At any one given time, there can be an abitrary number of USB drivers in
the system. The way driver mapping works (i.e, a device is inserted, and
a potentially matching driver is probed) requires us to have
instantiated driver objects _before_ a device is inserted. This leaves
us with a slight "chicken and egg" problem. We cannot call the probe
function before the driver is initialised, but we need to know _what_
driver to initialise.
This section is designed to store pointers to functions that are called
during the last stage of the early `_init` sequence in the Kernel. The
accompanying macro in `USBDriver` emits a symbol, based on the driver
name, into this table that is then automatically called.
This way, we enforce a "common" driver model; driver developers are not
only required to write their driver and inherit from `USB::Driver`, but
are also required to have a free floating init function that registers
their driver with the USB Core.
This commit lets us differentiate whether access faults are caused by
accessing junk memory addresses given to us by userspace or if we hit a
kernel bug.
The stub implementations of the `safe_*` functions currently don't let
us jump back into them and return a value indicating failure, so we
panic if such a fault happens. Practically, this means that we still
crash, but if the access violation was caused by something else, we take
the usual kernel crash code path and print a register and memory dump,
rather than hitting the `TODO_AARCH64` in `handle_safe_access_fault`.
This is the same address that the x86_64 kernel runs at, and allows us
to run the kernel at a high virtual memory address. Since we now run
completely in high virtual memory, we can also unmap the identity
mapping. Additionally some changes in MMU.cpp are required to
successfully boot.
For the initial page tables we only need to identity map the kernel
image, the rest of the memory will be managed by the MemoryManager. The
linker script is updated to get the kernel image start and end
addresses.
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.
By putting the NOLOAD sections (.bss and .super_pages) at the end of the
ELF file, objcopy does not have to insert a lot of zeros to make sure
that the .ksyms section is at the right place in memory. Now the .ksyms
section comes before the two NOLOAD sections. This shrinks the
kernel8.img with 6MB, from 8.3M to 2.3M. :^)
The sections did end up in the ELF file, however they weren't
explicitely mentioned in the linker.ld script. In the future, we can add
the --orphan-handling=error flag to the linker options, which will
enforce that the sections used in the sources files also are mentioned
in the linker script.
Previously the embedmap.sh script generated a warning, since there was
no section defined where the actual kernel.map could be stored. This is
necesarry for generating kernel backtraces.
As there is no need for a Prekernel on aarch64, the Prekernel code was
moved into Kernel itself. The functionality remains the same.
SERENITY_KERNEL_AND_INITRD in run.sh specifies a kernel and an inital
ramdisk to be used by the emulator. This is needed because aarch64
does not need a Prekernel and the other ones do.
2022-03-12 14:54:12 -08:00
Renamed from Kernel/Prekernel/Arch/aarch64/linker.ld (Browse further)
