Older ARM processors like ARMv6, or Cortex A8 need to write back changes
of the page-tables to physical ram because the MMU does not use the cache.
This naturally needs to be done not only when adding a mapping,
but on removal too.
Fix#3715
This patch adds support for booting base-hw kernel on qemu-arm virt
machines. The arm_virt machine has 2GB of RAM, 2 Cortex A15 cores and
uses GICv2 interrupt controller. The arm_64_virt machine also has 2GB of
RAM, but has 4 Cortex A53 cores and uses GICv3. Both machines use PSCI
to boot additional CPU cores.
Fixes#3673
This commit fixes the following issues regarding cache maintainance
under ARM:
* read out I-, and D-cache line size at runtime and use the correct one
* remove 'update_data_region' call from unprivileged syscalls
* rename 'update_instr_region' syscall to 'cache_coherent_region' to
reflect what it doing, namely make I-, and D-cache coherent
* restrict 'cache_coherent_region' syscall to one page at a time
* lookup the region given in a 'cache_coherent_region' syscall in the
page-table of the PD to prevent machine exceptions in the kernel
* only clean D-cache lines, do not invalidate them when pages where
added on Cortex-A8 and ARMv6 (MMU sees phys. memory here)
* remove unused code relicts of cache maintainance
In addition it introduces per architecture memory clearance functions
used by core, when preparing new dataspaces. Thereby, it optimizes:
* on ARMv7 using per-word assignments
* on ARMv8 using cacheline zeroing
* on x86_64 using 'rept stosq' assembler instruction
Fix#3685
Whether an SoC has the multiprocessing extensions can be read out
from the identification registers, and does not need to be specified
in each board header.
Ref #3445
In the past, the core-only privileged syscall `update_pd` was used only
to invalidate the TLB after removal of page-table entries.
By now, the whole TLB at least for one protection domain got invalidated,
but in preparation for optimization and upcomingARM v8 support,
it is necessary to deliver the virtual memory region that needs to get
invalidated. Moreover, the name of the call shall represent explicitely
that it is used to invalidate the TLB.
Ref #3405
Since gcc 8.3.0 generates SSE instructions into kernel code, the
kernel itself may raise FPU exceptions and/or corrupt user level FPU
contexts thereby. Both things are not feasible, and therefore, lazy FPU
switching becomes a no go for base-hw because we cannot avoid FPU
instructions because of the entanglement of base-hw, base, and the tool
chain (libgcc_eh.a).
issue #3365
Also disable TS (task switch) flag in cr0 during kernel initialization,
so FPU faults are not raised. This became necessary since GCC lately
aggressively generates FPU instructions at arbitrary places and also at
early kernel-bootstrapping stages.
fixes#3365
Instead of using `cps` instruction, use an exception return
instruction to switch from `hyp` mode to `svc` mode.
Otherwise it causes unpredicted behaviour on ARM.
Fix#3284
Track the dataspaces used by attach and add handling of flushing VM space
when dataspace gets destroyed (not triggered via the vm_session interface).
Issue #3111
As far as possible remove usage of warning/error/log in the kernel,
otherwise the kernel context might try to take a lock hold by a core
thread, which results in a syscall to block.
Fix#3277
* Introduce 64-bit tick counter
* Let the timer always count when possible, also if it already fired
* Simplify the kernel syscall API to have one current time call,
which returns the elapsed microseconds since boot
