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>
Instead of storing the current Processor into a core local register, we
currently just store it into a global, since we don't support SMP for
aarch64 anyway. This simplifies the initial implementation.
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.
Since kmalloc() now works, we can actually load the kernel symbol table!
This in turn allows us to call dump_backtrace(), and actually get a
useful backtrace in the aarch64 Kernel.
These functions are called by kmalloc, and since there is no support for
threading in the aarch64 build yet, we can simply remove the
VERIFY_NOT_REACHED().
The code in Spinlock.h has no architectural specific logic, thus can be
moved to the Arch directory. This contains no functional change.
Also add the Spinlock.cpp file for aarch64 which contains stubs for the
lock and unlock functions.
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.
Previously in the aarch64 Kernel, this would cause dbgln() to actually
print more characters of the next string in memory, because strings in
the Kernel are not zero terminated by default. Prevent this by using the
passed in length of the string.
When calling dbgln(), the formatting code in AK/Format.h calls
Processor::is_initialized() to determine whether to add some text about
the current processor to the debug output. Instead of crashing, we just
return false, such that we can use dbgln() etc in the aarch64 Kernel.
This allows us to use the AK formatting functions in the aarch64 Kernel.
Also add FIXME to make sure that this file will be removed when the
proper abstractions are in place in the normal Kernel/kprintf.cpp.
I've noticed that the KVM hypervisor vendor ID string contained null
terminators in the serialized JSON string in /proc/cpuinfo - let's avoid
that, and err on the side of caution and strip them from all strings
built from CPUID register values. They may not be fixed width after all.
