Extend Native_capability type to hold a specific selector index where the to
be received cap during a IPC should be mapped to. This feature is required to
place created caps by the cap_session at specific indexes. This feature is
used by Vancouver to setup the virtualization exception portals (created by
the cap_session) at the intended indexes.
Patch prevents following bugs:
* In sleep_forever the thread return from semaphore down if cap is revoked
during destruction of a thread. This causes an endless loop consuming time
not available for other threads.
* In lock_helper and cap_sel_alloc the thread return from the lock() method
even if the semaphore down call failed because of an revoked semaphore.
This lead to the situation that a thread subject to de-construction returns
from the lock method, but not holding the lock, entering the critical section
and modifying state inside the critical section. Another thread in parallel
already in the critical section or entering the critical section also
modifies the state. This lead to curious bugs ...
* thread_nova, thread_start, irq_session
Detect early bugs if the SM is gone unexpectedly where it should never
happen.
It now can hold a right bit used during IPC to demote rights of the to be
transfered capability.
The local_name field in the native_capability type is not needed anymore
in NOVA. Simplify the class, remove it from constructors and adapt all
invocations in base-nova.
Unfortunately local_name in struct Raw is still used in generic base code
(process.cc, reload_parent_cap.cc), however has no effect in base-nova.
MsgBuf has to keep the number of received capabilities in order
to free/know correctly unused and unwanted capabilities. Explicitly
call rcv_msg->post_ipc to store this information in a MsgBuf.
Don't reset rcv_msg in ipc.cc, since this is used during
un-marshalling of caps in ipc.h afterwards. The MsgBuf is reseted when its
de-constructor is called.
Kernel patch:
Introduce a transfer item type to express that a cap should be translated
and if this fails to map it instead.
It would be possible without this combined transfer item type however
with additional overhead. In this case Genode/NOVA would
have to map and translate all caps used as parameter in IPC. It would look
like this:
* If the map and translation succeed, the cap at the new cap index
would have to be revoked. Then the translated cap index can be used.
* If the map succeeds and the translation fails then the mapped cap index
can be used.
* It would become complicated when multiple caps are mapped and translated
and only some of the translation succeed. In such cases Genode would have
to figure out the right relation of translated/mapped and not
translated/mapped caps. It would require to make some assumption about the
order how translated/mapped caps are reported at the UTCB by the kernel.
All the points above lead to the decision to create a separate transfer item
type for that.
Genode:
Most the times the translation succeeds, mapping of caps happens either
seldom. This takes now a bit the pressure of not enough aligned receive
cap windows as described in issue #247.
The patch mainly adds adjustments to handle the
translated and mapped caps correctly especially during freeing of the
receive window (don't free translated cap indexes).
Fixes#268
If a thread has been deleted the thread object at the cpu_session was never
freed which caused the cpu_session quota to be exhausted as reported in
issue #150.
Fixes#150
The line-status register has two relevant status bits - transmitter-hold
register empty and data-hold register empty - from which only the THR is
relevant as it signals new character can be written to the device.
Fixes#281
Following deadlock happens when a Rm_client/Pager_object handles a page-fault
and concurrently the same object is dissolved (triggered by parent killing
the client).
The situation is as follows:
Page fault handling :
base-nova/src/base/pager/pager.cc : pf_handler() - lock pf_lock
base/.../core/rm_session_component.cc: pager() - lock rm_session
(in reverse_lookup())
Dissolve of Rm_client:
base/src/core/rm_session_component.cc: dissolve() - lock rm_session
base-nova/src/base/pager/pager.cc : dissolve() - lock pf_lock
The pf_lock is not required here during normal page fault handling,
since this pager object @NOVA is executed only by one and the same
thread and all critical operations inside the rm_session_object itself
are locked anyway. The only critical point is the destruction of the
Pager_object which is already handled in the both dissolve functions
of the rm-session_component (locking) and the pager_object (finalize
in-flight page faults).
Allocate exc_pt_sel inside Thread_base object
instead of pager object, since it is a thread
specific characteristic.
Same for freeing of the thread capabilities:
- ec, sc, rs, exc_pt_sel is thread specific
and has nothing to do in server nor pager object.
Use semaphore down feature of NOVA to set the counter to zero.
If the semaphore was up()ed more than one time by impatient callers
(e.g. guys calling cancel_blocking) we make sure that the thread
really stops.
Don't allocate ec cap twice, in pager.cc and thread_start.cc.
Unmap of utcb has to be done in destructor of thread class, not
in pager class. Free capability selectors of ec and rs.
Invoke cancel_blocking before calling the
cleanup portal of the rpc_entrypoint. If a rpc_entrypoint
is blocked in a semaphore the cleanup call gets
stuck forever.
The UTCB of the thread cleaning up thread objects has been unmapped.
However the UTCB of the destroyed thread must be unmapped.
Objects must explicitly be made unreachable before cleaning up. The
server and pager objects must be unreachable before they can be freed.
Both object types are threads. Revoking the thread(EC) cap on NOVA
doesn't mean that the thread stops executing. All portals pointing to a
thread are still reachable by clients even if the last EC cap is gone in
user land. So it must be taken care that no portals are pointing anymore
to a thread when the associated objects are getting destroyed. This
commit handles this.
Additionally, even if the last portal is gone - there can be still an
ongoing request handled by such server/pager object/threads. For each
such object an additional portal is created. This object is called
'cleanup portal' and is only local to the object. After all portals are
revoked the cleanup portal is called. When the call returns we know that
nobody is anymore handled by the object since all remotely available
portals are gone.
Fixes#20
Use git to get recent kernels from github. Adjust NOVA patch to compile
with recent github version. Patch and use makefile of NOVA microkernel
to avoid duplicated (and outdated) makefile in Genode
Furthermore, this patch adds support for using NOVA on x86_64. The
generic part of the syscall bindings has been moved to
'base-nova/include/nova/syscall-generic.h'. The 32/64-bit specific
parts are located at 'base-nova/include/32bit/nova/syscalls.h' and
'base-nova/include/64bit/nova/syscalls.h' respectively.
On x86_64, the run environment boots qemu using the Pulsar boot loader
because GRUB legacy does not support booting 64bit ELF executables.
In addition to the NOVA-specific changes in base-nova, this patch
rectifies compile-time warnings or build errors in the 'ports' and
'libports' repositories that are related to NOVA x86_64 (i.e., Vancouver
builds for 32bit only and needed an adaptation to NOVAs changed
bindings)
Fixes#233, fixes#234
The 'copy_to' function turned out to be not flexible enough to
accommodate the Noux fork mechanism. This patch removes the function,
adds an accessor for the capability destination and a compound type
'Native_capability::Raw' to be used wherever plain capability
information must be communicated.
This patch unifies the Native_capability classes for the different kernel
platforms by introducing an appropriate template, and eliminating naming
differences. Please refer issue #145.
