Ldso now does not automatically execute static constructors of the
binary and shared libraries the binary depends on. If static
construction is required (e.g., if a shared library with constructor is
used or a compilation unit contains global statics) the component needs
to execute the constructors explicitly in Component::construct() via
Genode::Env::exec_static_constructors().
In the case of libc components this is done by the libc startup code
(i.e., the Component::construct() implementation in the libc).
The loading of shared objects at runtime is not affected by this change
and constructors of those objects are executed immediately.
Fixes#2332
This patch destructs the environment sessions for the binary and the
dynamic linker along with the other environment sessions to avoid a
warning about reverting quota that occurs when attempting to close
these sessions too late.
The race may happen when element objects get destructed by another thread then
the thread handling the for_each loop. In this case it may happen that the
object is already destructed (left the ~Element destructor) but the thread
handling the loop touches the invalid memory afterwards (the Element lock).
detected during issue #2299Fixes#2320
With the commit "init: session-label rewriting", the stack usage
increased due to the handling of session-label strings as local
variables. The stack overrun occurred in the vmm scenario on
base-hw.
There was a race when the component entrypoint wanted to do
'wait_and_dispatch_one_signal'. In this function it raises a flag for
the signal proxy thread to notice that the entrypoint also wants to
block for signals. When the flag is set and the signal proxy wakes up
with a new signal, it tried to cancel the blocking of the entrypoint.
However, if the entrypoint had not reached the signal blocking at this
point, the cancel blocking failed without a solution. Now, the new
Kernel::cancel_next_signal_blocking call solves the problem by storing a
request to cancel the next signal blocking of a thread immediately
without blocking itself.
Ref #2284
It can happen that when Cpu_free_component is constructed the insertion
of the object through 'manage' succeeds for the EP put not for the pager
EP, which in turn raises an Out_of_meta_data exception. Because we are
within the constructor, the descstructor is not called, leading to a
dangling object pool entry for the EP.
issue #2289
This patch enhances the 'Child' and 'Child_policy' with the ability to
separate the different steps of bootstrapping children. If the
'Child_policy::initiate_env_sessions()' returns false, the child's
environment sessions remain unrouted at construction time. This way,
child objects for many children can be initialized to a state that
allows the children to represent services for other children. Therefore,
session routing can be applied before any child executes.
At this stage, the environment RAM sessions of all children can be
created. Note that this step still has the limitation that RAM sessions
are generally expected to be provided by either the parent or a local
service.
Once all children are equipped with RAM, they can in principle receive
session-quota donations. Hence, all other environment sessions can now
be arbitrarily routed and initiated.
Once the environment of a child is complete, the child's process and
initial thread is created.
This patch improves the accounting for the backing store of
session-state meta data. Originally, the session state used to be
allocated by a child-local heap partition fed from the child's RAM
session. However, whereas this approach was somehow practical from a
runtime's (parent's) point of view, the child component could not count
on the quota in its own RAM session. I.e., if the Child::heap grew at
the parent side, the child's RAM session would magically diminish. This
caused two problems. First, it violates assumptions of components like
init that carefully manage their RAM resources (and giving most of them
away their children). Second, if a child transfers most of its RAM
session quota to another RAM session (like init does), the child's RAM
session may actually not allow the parent's heap to grow, which is a
very difficult error condition to deal with.
In the new version, there is no Child::heap anymore. Instead, session
states are allocated from the runtime's RAM session. In order to let
children pay for these costs, the parent withdraws the local session
costs from the session quota donated from the child when the child
initiates a new session. Hence, in principle, all components on the
route of the session request take a small bite from the session quota to
pay for their local book keeping
Consequently, the session quota that ends up at the server may become
depleted more or less, depending on the route. In the case where the
remaining quota is insufficient for the server, the server responds with
'QUOTA_EXCEEDED'. Since this behavior must generally be expected, this
patch equips the client-side 'Env::session' implementation with the
ability to re-issue session requests with successively growing quota
donations.
For several of core's services (ROM, IO_MEM, IRQ), the default session
quota has now increased by 2 KiB, which should suffice for session
requests to up to 3 hops as is the common case for most run scripts. For
longer routes, the retry mechanism as described above comes into effect.
For the time being, we give a warning whenever the server-side quota
check triggers the retry mechanism. The warning may eventually be
removed at a later stage.
This method is a hook to enable a runtime to respond to state changes.
In particular, in init this hook is used to trigger the generation of a
new state report, if configured.
Furthermore, the patch introduces the 'generate_client_side_info' and
'generate_server_side_info' methods to the 'Session_state', which
generates an XML representation of the session states to appear in
reports produced by init.
Issue #2246
The new return value of 'resolve_session_request' allows the child
policy to define the label used as the policy selector at the server.
Because this patch introduces the distinction of the child-provided
label from the label as presented to the server along with the session
request, the latter is now handled as a dedicated 'Session_state'
argument.
Issue #2248
There existed a race when 'wait_and_dispatch_one_signal' is called form
a RPC context, because the 'signal_proxy' or 'main' will block and the
signal semaphore, when the EP then calls 'wait_and_dispatch_one_signal',
the signal proxy is woken up ands sends an RPC to the EP, leading to a
dead lock if no further signal arrive, because the EP will then remain
blocked in the signal semaphore.
Therefore, for this case, the signal proxy will now perform a semaphore
up operation and does not perform an RPC if the EP is within
'wait_and_dispatch_one_signal'.
First, calls to manage and dissolve signal contexts now check if the
signal receiver was constructed. There is a small window during suspend
where it is destructed before reconstructed again.
Last, we ensure that processing of incoming signal was deblocked by the
suspend signal before entering the suspend operation. This way we ensure
already queued signal are handled.
This commit enables compile-time warnings displayed whenever a deprecated
API header is included, and adjusts the existing #include directives
accordingly.
Issue #1987
If the detach address is not the beginning of the region, one gets:
"virtual void Genode::Allocator_avl_base::free(void*): given
address (0x180e0) is not the block start address (0x18000)"
Instead, print an explicit warning in front of the detach call.
This commit addresses the situation where an environment session
outlives the session-providing service. In this case, the env session
got already invaidated at the destruction time of the server. However,
the underlying session-state structure continues to exist until the
client is destructed. During the eventual destruction of such a dangling
environment session, we have to be careful not to interact with the
no-longer existing service.
Ref #2197
This patch addresses the corner case of destructing a child that
provides an enviroment session to another child. Before this patch,
this situation could result in an infinite loop.
The problem was introduced as a side effect of issue #2197 "base: apply
routing policy to environment sessions".
This patch enables warnings if one of the deprecate functions that rely
in the implicit use of the global Genode::env() accessor are called.
For the time being, some places within the base framework continue
to rely on the global function while omitting the warning by calling
'env_deprecated' instead of 'env'.
Issue #1987
This patch removes the component_entry_point library, which used to
proved a hook for the libc to intercept the call of the
'Component::construct' function. The mechansim has several shortcomings
(see the discussion in the associated issue) and was complex. So we
eventually discarded the approach in favor of the explicit handling of
the startup.
A regular Genode component provides a 'Component::construct' function,
which is determined by the dynamic linker via a symbol lookup.
For the time being, the dynamic linker falls back to looking up a 'main'
function if no 'Component::construct' function could be found.
The libc provides an implementation of 'Component::construct', which
sets up the libc's task handling and finally call the function
'Libc::Component::construct' from the context of the appllication task.
This function is expected to be provided by the libc-using application.
Consequently, Genode components that use the libc have to implement the
'Libc::Component::construct' function.
The new 'posix' library provides an implementation of
'Libc::Component::construct' that calls a main function. Hence, POSIX
programs that merely use the POSIX API merely have to add 'posix' to the
'LIBS' declaration in their 'target.mk' file. Their execution starts at
'main'.
Issue #2199
These functions are marked as always inline through the 'SELF_RELOC' macro. This
became necessary because on riscv functions calls are performed through the
global offset table, which is not initialized at this point.
Fixes#2203
This patch removes the manually maintained symbol map from the dynamic
linker. This way, the symbol map stays in sync with the ABI and - more
importantly - no longer uses wildcards. So the symbols exported by the
dynamic linker are strictly limited by the ABI.
Issue #2190
This patch changes the child-construction procedure to allow the routing
of environment sessions to arbitrary servers, not only to the parent.
In particular, it restores the ability to route the LOG session of the
child to a LOG service provided by a child of init. In principle, it
becomes possible to also route the immediate child's PD, CPU, and RAM
environment sessions in arbitrary ways, which simplifies scenarios that
intercept those sessions, e.g., the CPU sampler.
Note that the latter ability should be used with great caution because
init needs to interact with these sessions to create/destruct the child.
Normally, the sessions are provided by the parent. So init is safe at
all times. If they are routed to a child however, init will naturally
become dependent on this particular child. For the LOG session, this is
actually not a problem because even though the parent creates the LOG
session as part of the child's environment, it never interacts with the
session directly.
Fixes#2197
This patch removes possible ambiguities with respect to the naming of
kernel-dependent binaries and libraries. It also removes the use of
kernel-specific global side effects from the build system. The reach of
kernel-specific peculiarities has thereby become limited to the actual
users of the respective 'syscall-<kernel>' libraries.
Kernel-specific build artifacts are no longer generated at magic places
within the build directory (like okl4's includes, or the L4 build
directories of L4/Fiasco and Fiasco.OC, or the build directories of
various kernels). Instead, such artifacts have been largely moved to the
libcache. E.g., the former '<build-dir>/l4/' build directory for the L4
build system resides at '<build-dir>/var/libcache/syscall-foc/build/'.
This way, the location is unique to the kernel. Note that various tools
are still generated somewhat arbitrarily under '<build-dir>/tool/' as
there is no proper formalism for building host tools yet.
As the result of this work, it has become possible to use a joint Genode
build directory that is usable with all kernels of a given hardware
platform. E.g., on x86_32, one can now seamlessly switch between linux,
nova, sel4, okl4, fiasco, foc, and pistachio without rebuilding any
components except for core, the kernel, the dynamic linker, and the timer
driver. At the current stage, such a build directory must still be
created manually. A change of the 'create_builddir' tool will follow to
make this feature easily available.
This patch also simplifies various 'run/boot_dir' plugins by removing
the option for an externally hosted kernel. This option remained unused
for many years now.
Issue #2190
The header is foc-specific. It used to shadow the generic one provided
by the base repository, which contradicts with the kernel-agnostic
Genode API. Hence, it had to be moved to a foc-specific location.
The main thread does no longer execute application code. It is solely
responsible for the initialization of the component's entrypoint and for
retrieving asynchronous notifications. Since the stack usage is no
longer dependent on application-specific code, we can significantly
shrink it to reduce the memory footprint of components. In the worst
case - should the stack overrun - we would observe a page fault because
the stack is placed in the stack area, surrounded by guard pages.
This patch replaces the former machine-word-dependent default stack size
by the fixed value of 64 KiB which should suffice for components on both
32 and 64 bit. Previously, the default stack size on 64 bit was 128 KiB,
which is wasteful. If a component needs more stack than 64 KiB, it can
specify a custon stack size by implementing 'Component::stack_size'.
The initial stack is solely used to initialize the Genode environment
along with the application stack located in the stack area. It never
executes application code. Hence, we can make it small. To check that it
is not dimensioned too small, the patch introduces a sanity check right
before switching to the application stack.
