Instead of mapping all physical memory 1:1 into core/kernel's address space,
this commit limits the 1:1 mapping to the binary image, and I/O memory
regions used by the kernel only. All subsequent memory accesses of core
are done by mapping the corresponding memory on demand, and not necessarily
1:1.
This commit has several side effects:
The page table code had to be revisited completely. The kernel inserts no
longer anything into the page tables, apart from the initial translations
to have the core/kernel image available when enabling the MMU. The page
tables and higher level translation tables are no longer named Tlb, but
Translation_table instead. There is no indirection class required to define
the translation tables of a concrete SoC, the appropriated ARM specifier
is sufficient.
The ability to map core's memory the same way like it's done for all other
protection domains, makes a special treatment of core's threads (no context
area) obsolete.
Ref #567 (partly solves it)
Fix#723Fix#1068
Removes the generic processor broadcast function call. By now, that call
was used for cross processor TLB maintance operations only. When core/kernel
gets its memory mapped on demand, and unmapped again, the previous cross
processor flush routine doesn't work anymore, because of a hen-egg problem.
The previous cross processor broadcast is realized using a thread constructed
by core running on top of each processor core. When constructing threads in
core, a dataspace for its thread context is constructed. Each constructed
RAM dataspace gets attached, zeroed out, and detached again. The detach
routine requires a TLB flush operation executed on each processor core.
Instead of executing a thread on each processor core, now a thread waiting
for a global TLB flush is removed from the scheduler queue, and gets attached
to a TLB flush queue of each processor. The processor local queue gets checked
whenever the kernel is entered. The last processor, which executed the TLB
flush, re-attaches the blocked thread to its scheduler queue again.
To ease uo the above described mechanism, a platform thread is now directly
associated with a platform pd object, instead of just associate it with the
kernel pd's id.
Ref #723
Kernel::resume_thread was restricted to core when the targeted thread was in
another domain. Now there are two kernel calls, resume_local_thread and
resume_thread, where the former is never restricted and is provided via
public kernel/interface.h and the latter is always restricted to core and
is provided via core-local kernel/core_interface.h.
ref #1101
Kernel::pause_current_thread can be implemented much simpler and is not
restricted to core threads, in contrast to Kernel::pause_thread which
also benefits from the split and can be moved to core_interface.h.
ref #1101
If an RM fault ends up in any trouble, the faulter remains paused and
the pager activation continues with the next fault. Thus we can print
a warning instead of an error and safe execution time in release mode.
ref #1096
In most cases an error report is not necessary in the kernel as the problem
does not affect the kernel itself but the according user-land context. Thus
we can also do a warning that is not printed in release mode and hence safe
execution time.
ref #1096
Previously for determining wether boot-up succeeded or not, we looked
for a message that is switched off in release mode. Now the kernel
provides a reliable message as soon as initialization is done.
ref #1096
Stefan Kalkowski
Martin Stein
Alexander Boettcher