For asynchronously provided sessions, the parent has to maintain the
session state as long as the server hasn't explicitly responded to a
close request. For this reason, the lifetime of such session states is
bound to the server, not the client.
When the server responds to a close request, the session state gets
freed. The 'session_response' implementation does not immediately
destroy the session state but delegates the destruction to a client-side
callback, which thereby also notifies the client. However, the code did
not consider the case where the client has completely vanished at
session-response time. In this case, we need to drop the session state
immediately.
Fixes#2391
The base class of Registered must provide a virtual destructor to enable
safe deletion with just a base class pointer. This requirement can be
lifted by using Registered_no_delete in places where the deletion
property is not needed.
Fixes#2331
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
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
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
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
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.
This patch unconditionally applies the labeling of sessions and thereby
removes the most common use case of 'Child_policy::filter_session_args'.
Furthermore, the patch removes an ambiguity of the session labels of
sessions created by the parent of behalf of its child, e.g., the PD
session created as part of 'Child' now has the label "<child-name>"
whereas an unlabeled PD-session request originating from the child
has the label "<child-name> -> ". This way, the routing-policy of
'Child_policy::resolve_session_request' can differentiate both cases.
As a consequence, the stricter labeling must now be considered wherever
a precise label was specified as a key for a session route or a server-
side policy selection. The simplest way to adapt those cases is to use a
'label_prefix' instead of the 'label' attribute. Alternatively, the
'label' attribute may used by appending " -> " (note the whitespace).
Fixes#2171
The heap typically first tries to allocate larger chunks than necessary, and
if it fails the actual minimal one. The first attempt already triggers warnings
which are not critical at all. If the second (critical) allocation fails,
then there are additionally checks and warnings already in place.
Issue #1039
This is a redesign of the root and parent interfaces to eliminate
blocking RPC calls.
- New session representation at the parent (base/session_state.h)
- base-internal root proxy mechanism as migration path
- Redesign of base/service.h
- Removes ancient 'Connection::KEEP_OPEN' feature
- Interface change of 'Child', 'Child_policy', 'Slave', 'Slave_policy'
- New 'Slave::Connection'
- Changed child-construction procedure to be compatible with the
non-blocking parent interface and to be easier to use
- The child's initial LOG session, its binary ROM session, and the
linker ROM session have become part of the child's envirenment.
- Session upgrading must now be performed via 'env.upgrade' instead
of performing a sole RPC call the parent. To make RAM upgrades
easier, the 'Connection' provides a new 'upgrade_ram' method.
Issue #2120
This data structure is meant as a safe alternative for a list wherever
the list is solely used to remember objects and iterate through them in
an unspecified order. One use case is the 'Service_registry'.
This fixes a regression on Ubuntu 16.04 (resp. Linux systems with recent
kernel versions) and address-space randomization originating from an
uninitialized relocation base of 0.
This patch fixes a race condition triggered by the thread test running
on Linux inside VirtualBox. The 'test_stack_alloc' sporadically produced
one of two errors: A segfault in the 'Thread::deinit_platform_thread' on
the attempt to access the 'native_thread' of the to-be-destructed thread
(this data structure is located on the thread's stack). Or, an error
message about a region conflict within the stack area.
The problem was that two instances of 'Region_map_mmap' issued a
sequence of munmap and mmap each. Even though each instance locked the
attach/detach operations, the lock was held per instance. In a situation
where two instances performed attach/detach operations in parallel, the
syscall sequences could interfere with each other.
In the test scenario, the two region-map instances are the test's
address space and the stack area. When creating a thread, the thread's
trace-control dataspace is attached at an arbitrary place (picked by
the Linux kernel) within the address space whereas the stack is attached
at the stack area. The problem is the following sequence:
Thread A wants to destruct a thread:
1. Remove stack from stack area
(issue unmap syscall)
2. Preserve virtual address range that was occupied from the stack
so that Linux won't use it
(issue mmap syscall)
Thread B wants to construct a thread:
1. Request trace-control dataspace from CPU session
2. Attach trace-control dataspace to address space at a location
picked by the Linux kernel
(issue mmap syscall)
The problem occurs when thread B's second step is executed in between
the steps 1 and 2 of thread A and the Linux kernel picks the
just-unmapped address as the location for the new trace-control mapping.
Now, the trace control dataspace is mapped at the virtual address that
was designated for the stack of the to-be-created thread, and the
attempt to map the real stack fails.
The patch fixes the problem by replacing the former region-map-local
locks by a component-global lock.
Furthermore, it cleans up core's implementation of the support function
for the region-map-mmap implementation, eliminating the temporary
unlocking of the region-map lock during RPC.
Instead of solving the problem to deliver ROM modules to core while booting
differently for the several kernels (multi-boot, elfweaver, core re-linking),
this commit unifies the approaches. It always builds core as a library, and
after all binaries are built from a run-script, the run-tool will link an
ELF image out of the core-library and all boot modules. Thereby, core can
access its ROM modules directly.
This approach now works for all kernels except Linux.
With this solution, there is no [build_dir]/bin/core binary available anymore.
For debugging purposes you will find a core binary without boot modules, but
with debug symbols under [run_dir].core.
Fix#2095
base generic code:
* Remove unused verbosity code from mmio framework
* Remove escape sequence end heuristic from LOG
* replace Core_console with Core_log (no format specifiers)
* move test/printf to test/log
* remove `printf()` tests from the log test
* check for exact match of the log test output
base-fiasco:
* remove unused Fiasco::print_l4_threadid function
base-nova:
* remove unused hexdump utility from core
base-hw:
* remove unused Kernel::Thread::_print_* debug utilities
* always print resource summary of core during startup
* remove Kernel::Ipc_node::pd_label (not used anymore)
base*:
* Turn `printf`,`PWRN`, etc. calls into their log equivalents
Ref #1987Fix#2119
Besides adapting the components to the use of base/log.h, the patch
cleans up a few base headers, i.e., it removes unused includes from
root/component.h, specifically base/heap.h and
ram_session/ram_session.h. Hence, components that relied on the implicit
inclusion of those headers have to manually include those headers now.
While adjusting the log messages, I repeatedly stumbled over the problem
that printing char * arguments is ambiguous. It is unclear whether to
print the argument as pointer or null-terminated string. To overcome
this problem, the patch introduces a new type 'Cstring' that allows the
caller to express that the argument should be handled as null-terminated
string. As a nice side effect, with this type in place, the optional len
argument of the 'String' class could be removed. Instead of supplying a
pair of (char const *, size_t), the constructor accepts a 'Cstring'.
This, in turn, clears the way let the 'String' constructor use the new
output mechanism to assemble a string from multiple arguments (and
thereby getting rid of snprintf within Genode in the near future).
To enforce the explicit resolution of the char * ambiguity, the 'char *'
overload of the 'print' function is marked as deleted.
Issue #1987
and show some message about. On sel4 sometimes exceptions are thrown and no
message is shown, it just seems to hang. With this patch at least you get
an idea that something bad happened.
Issue #2044
Those headers implement a platform-specific mechanism. They are never
used by components directly.
This patch also cleans up a few other remaining platform-specific
artifact such as the Fiasco.OC-specific assert.h.
Issue #1993
This patch establishes the sole use of generic headers across all
kernels. The common 'native_capability.h' is based on the version of
base-sel4. All traditional L4 kernels and Linux use the same
implementation of the capability-lifetime management. On base-hw, NOVA,
Fiasco.OC, and seL4, custom implementations (based on their original
mechanisms) are used, with the potential to unify them further in the
future.
This change achieves binary compatibility of dynamically linked programs
across all kernels.
Furthermore, the patch introduces a Native_capability::print method,
which allows the easy output of the kernel-specific capability
representation using the base/log.h API.
Issue #1993
This patch alleviates the need for a Native_capability::Dst at the API
level. The former use case of this type as argument to
Deprecated_env::reinit uses the opaque Native_capability::Raw type
instead. The 'Raw' type contains the portion of the capability that is
transferred as-is when delegating the capability (i.e., when installing
the parent capability into a new component, or when installing a new
parent capability into a new forked Noux process). This information can
be retrieved via the new Native_capability::raw method.
Furthermore, this patch moves the functions for retriving the parent
capability to base/internal/parent_cap.h, which is meant to be
implemented in platform-specific ways. It replaces the former set of
startup/internal/_main_parent_cap.h headers.
Issue #1993
The static 'Thread::mystack()' function returns the stack boundaries of
the calling thread. It is useful when a thread uses a diffent stack than
the primary one.
Fixes#2037
This patch introduces the Genode::raw function that prints output
directly via a low-level kernel mechanism, if available.
On base-linux, it replaces the former 'raw_write_str' function.
On base-hw, it replaces the former kernel/log.h interface.
Fixes#2012
- add a new function 'binary_ready_hook_for_gdb()' in ldso. GDB can set a
breakpoint at this function to know when ldso has loaded the binary
into memory.
- get the thread state from the NOVA kernel immediately on 'pause()'
Fixes#1968
This patch moves the thread operations from the 'Cpu_session'
to the 'Cpu_thread' interface.
A noteworthy semantic change is the meaning of the former
'exception_handler' function, which used to define both, the default
exception handler or a thread-specific signal handler. Now, the
'Cpu_session::exception_sigh' function defines the CPU-session-wide
default handler whereas the 'Cpu_thread::exception_sigh' function
defines the thread-specific one.
To retain the ability to create 'Child' objects without invoking a
capability, the child's initial thread must be created outside the
'Child::Process'. It is now represented by the 'Child::Initial_thread',
which is passed as argument to the 'Child' constructor.
Fixes#1939
It turns out that the name function does not have much use in practice
except for naming the thread of the component's initial entrypoint. For
dynamically linked components, this thread is created by the dynamic
linker. It is named "ep" in these cases. Considering that we will
eventually turn all regular components into dynamically linked
executables, the additional information provided by the
Component::name() function remains unused. So it is better to not bother
the component developers with adding boilerplate code.
Now rlibs are actually linked to programs. Target files have been
modified to not generate code that requires compiler-rt. Added a target
for libstd-rust, but it's very broken right now. Moved alloc_system to
the libports folder because either a memory allocator needs to be
written in rust or posix_memalign needs to be implemented. Changed
liblibc to use freebsd as the OS instead of netbsd. Added a library with
unwind dummy functions.
Rust relies on atomic builtins, which are not implemented in libgcc for
ARM. One was implemented in rust, which was sufficient to get the
current rust test to run. Rust libs were added into the group of libs
for the linker so order no longer matters. The raspberry pi now uses an
armv6 target.
This patch cleans up the thread API and comes with the following
noteworthy changes:
- Introduced Cpu_session::Weight type that replaces a formerly used
plain integer value to prevent the accidental mix-up of
arguments.
- The enum definition of Cpu_session::DEFAULT_WEIGHT moved to
Cpu_session::Weight::DEFAULT_WEIGHT
- New Thread constructor that takes a 'Env &' as first argument.
The original constructors are now marked as deprecated. For the
common use case where the default 'Weight' and 'Affinity' are
used, a shortcut is provided. In the long term, those two
constructors should be the only ones to remain.
- The former 'Thread<>' class template has been renamed to
'Thread_deprecated'.
- The former 'Thread_base' class is now called 'Thread'.
- The new 'name()' accessor returns the thread's name as 'Name'
object as centrally defined via 'Cpu_session::Name'. It is meant to
replace the old-fashioned 'name' method that takes a buffer and size
as arguments.
- Adaptation of the thread test to the new API
Issue #1954
This patch moves the base library from src/base to src/lib/base,
flattens the library-internal directory structure, and moves the common
parts of the library-description files to base/lib/mk/base.inc and
base/lib/mk/base-common.inc.
Furthermore, the patch fixes a few cosmetic issues (whitespace and
comments only) that I encountered while browsing the result.
Fixes#1952
The original 'Env' interface as returned by 'Genode::env()' has been
renamed to 'Env_deprecated' and moved to deprecated/env.h. The new version
of base/env.h contains the interface passed to modern components that
use the component API via base/component.h.
Issue #1832
This patch integrates three region maps into each PD session to
reduce the session overhead and to simplify the PD creation procedure.
Please refer to the issue cited below for an elaborative discussion.
Note the API change:
With this patch, the semantics of core's RM service have changed. Now,
the service is merely a tool for creating and destroying managed
dataspaces, which are rarely needed. Regular components no longer need a
RM session. For this reason, the corresponding argument for the
'Process' and 'Child' constructors has been removed.
The former interface of the 'Rm_session' is not named 'Region_map'. As a
minor refinement, the 'Fault_type' enum values are now part of the
'Region_map::State' struct.
Issue #1938
This commit introduces the new `Component` interface in the form of the
headers base/component.h and base/entrypoint.h. The os/server.h API
has become merely a compatibilty wrapper and will eventually be removed.
The same holds true for os/signal_rpc_dispatcher.h. The mechanism has
moved to base/signal.h and is now called 'Signal_handler'.
Since the patch shuffles headers around, please do a 'make clean' in the
build directory.
Issue #1832
Rust relies on atomic builtins, which are not implemented in libgcc for
ARM. One is implemented in rust, which is sufficient to get the
current rust test to run.
Issue #1899
Check if the binary pointer is valid before attempting to lookup the
symbol. Shared objects with unresolved symbols and missing depencies,
e.g a library that references 'errno' but is not linked against libc,
will now produce an error message when they are loaded by the dynamic
linker.
Fixes#1904.
This patch moves details about the stack allocation and organization
the base-internal headers. Thereby, I replaced the notion of "thread
contexts" by "stacks" as this term is much more intuitive. The fact that
we place thread-specific information at the bottom of the stack is not
worth introducing new terminology.
Issue #1832
This patch establishes a common organization of header files
internal to the base framework. The internal headers are located at
'<repository>/src/include/base/internal/'. This structure has been
choosen to make the nature of those headers immediately clear when
included:
#include <base/internal/lock_helper.h>
Issue #1832
On Linux the linker can now be loaded at arbitrary addresses, this became
necessary for newer kernel versions. The 'linux_arm' target is not supported.
Issue #1728
Instead of holding SPEC-variable dependent files and directories inline
within the repository structure, move them into 'spec' subdirectories
at the corresponding levels, e.g.:
repos/base/include/spec
repos/base/mk/spec
repos/base/lib/mk/spec
repos/base/src/core/spec
...
Moreover, this commit removes the 'platform' directories. That term was
used in an overloaded sense. All SPEC-relative 'platform' directories are
now named 'spec'. Other files, like for instance those related to the
kernel/architecture specific startup library, where moved from 'platform'
directories to explicit, more meaningful places like e.g.: 'src/lib/startup'.
Fix#1673
On ARM, the compiler generates calls to memcpy and memset. Most
dynamically linked programs use the libc, which provides these
functions. However, if a dynamically linked program does not use the
libc (e.g., noux/minimal or the new version of cli_monitor), those
symbols remain unresolved. By adding them to ldso's symbol.map, the
dynamic linker will resolve them with the functions of the cxx
library, which is part of the dynamic linker.
Issue #1561
This has to be used during shared object creation and destruction because global
lists are manipulated. We cannot use the 'Elf_object::lock' here because there
may be jump-slot relocations during object initialization.
Fixes#1350
This wasn't necessary before because we built an l4 library for
Pistachio and linked it against each application. With the new linker,
we compile the required files from within Genode and create a syscall
library that is only linked to ldso. If a program uses system calls
directly, for example, DDE kit's spinlock implementation, the required
symbols must be made globally accessible.
Fixes#1306
Do not support the global construction from of objects from within a global
constructor of another object. This can happen if, for example, dlopen is called
from a global constructor. The construction will be post-boned until the current
constructor has finished.
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.
Issue #1082
