changes. The alternative settings get reread on all interfaces as done before
"qemu-usb: fix device endpoint update" commit by introducing specific
reset_alt_settings function. The fallthrough case was intentionally before
the "qemu-usb: fix device endpoint update" case, which now is wrong.
Issue #4596
This style is used by the upcoming phone version of Sculpt for GUI
elements that are supposed to stand out a little bit more than the
regular frame style.
This patch enhances menu_view with the optional configuration attributes
'opaque' and 'background'. Setting 'opaque' to "yes" suppresses the use
of the alpha channel at the GUI session. This improves the drawing
performance by 20% on the PinePhone. Since the menu_view uses the
gems/gui_buffer.h utility, the 'Gui_buffer' received a new 'Alpha'
argument at construction time.
The 'background' attribute can be specified to define the reset color of
the GUI buffer. It alleviates the need to create a frame widget for the
top level.
The patch also switches the optimization level for compiling menu_view
to -O3, which increases the drawing performance on the PinePhone by 30%.
Fixes#4592
This change increases the quota to allow the use of bigger fonts, and
tweaks the style such that the keyboard gets a decent appearance on the
PinePhone's 1440x720 display.
This patch adds principle support for using a USB-net modem as
mobile-data uplink. The change is motivated by the upcoming phone
manager for the PinePhone where the modem serves as the primary network
uplink. For the regular PC version of Sculpt, the feature is not needed
(hence remains disabled) because USB net can be deployed from a package
as described in:
https://genodians.org/jschlatow/2021-07-21-mobile-network
The patch also renames the "Local" network option to "Disconnected" to
be more intuitive.
By decoupling the network dialog's menu view from the 'Network' class,
we become able to host the network dialog in the same menu view instance
as other dialogs.
This patch allows the sculpt manager hosted in the leitzentrale
subsystem to observe the toggling between the runtime and the
administrative GUI. This enables alternatives to the use of the
gui_fader for switching between both views. In particular, the
upcoming phone_manager toggles the visibility of its own GUI
depending on the leitzentrale state.
In a Sculpt system based on the upcoming phone_manager, the event filter
obtains its static configuration from /config/managed/event_filter.
Without the requirement for changes at runtime, there is no need to
have the phone_manager in the loop after all.
Without this patch however, this file was always initialized with the
template gems/sculpt/event_filter/default, which was presumably used
only at boot time until the sculpt manager has produced the first
generated event-filter configuration.
This patch applies the choice of optional configs - i.e., a custom
event_filter config - to both the config/ and the initial content of
config/managed/. So in cases where the /config/managed/event_filter
remains entirely static, the latter properly reflects the choosen
variant.
By using the new functions provided by the base API, this patch removes
the dependency of several components from include/decorator/xml_utils.h.
Issue #4584
The NIC router used to send an ICMP "Destination Unreachable" packet as
response to every unroutable IPv4 packet. However, RFC 1812 section 4.3.2.7
defines certain properties that must be fullfilled by an incoming packet in
order to be answered with this type of ICMP. One requirement is that the packet
is no IPv4 multicast.
This commit prevents sending the mentioned ICMP response for unroutable IPv4
multicasts and instead drops them silently.
Fixes#4563
This patch allows the leitzentrale subsystem to control an audio driver
hosted in the drivers subsystem. An example use case is the toggling of
the speaker during phone calls.
Instead of having a generic "virt_qemu" board use "virt_qemu_<arch>" in
order to have a clean distinction between boards. Current supported
boards are "virt_qemu_arm_v7a", "virt_qemu_arm_v8a", and
"virt_qemu_riscv".
issue #4034
Define custom analyses that can be imported into TraceCompass (>= 7.3)
for evaluating the traced component interactions and checkpoints.
genodelabs/genode#4352
The NIC router used to add the DNS servers field to DHCP replies regardless of
whether there were DNS servers or not. As reported by a Genode user, the empty
DNS server field irritated at least Windows 10 guests (Vbox 6) that connected
to the NIC router. This resulted in Windows 10 ignoring DHCP offers from the
router with such characteristic.
With this commit adding the DNS server DHCP option is skipped if there are no
DNS servers at the corresponding DHCP server or the domain IP config the server
shall fetch its DNS servers from.
Fixes#4581
Skip SET_CONFIGURATION requests if the device already has the selected
config as active config. This workaround prevents issues with Linux
guests in VirtualBox and SDC-reader passthrough.
Thanks to Peter for the patch.
The commit introduces means to mark a task for destruction that is
removed on the next scheduling cycle. This fixes stack leakage from
dynamic kworker tasks.
Issue #4575.
Provide additional PCI register information inside the pci-config part
of the devices ROM for clients able to access an Intel graphic card,
namely the GMCH control register content, which contains for instance
the GTT size and stolen memory size.
Ref genodelabs/genode#4578
Implement BIOS handover and Intel resume register update
apart from device driver to circumvent export of PCI
config space to drivers.
Ref genodelabs/genode#4578
The pci_decode has to extract the additional fields from the PCI configuration
space. The platform driver again has to parse and forward the knowledge too.
The PCI BAR indices are exported when info="yes" is set in the policy node for
the corresponding session.
Fixgenodelabs/genode#4577
The base address of I/O ports has a different encoding than
those of I/O memory. This needs to be encountered in the PCI
config helper utilities.
Fixgenodelabs/genode#4576
Under high TX load, 'irq_handler()' is rarely executed but packets
are still received since 'netdev_poll()' is called for every TX packet.
'netdev_poll()' not only handles completed transmissions but also
puts the IO buffers of received packets into the RX queue and refills the RX
ring by allocating more IO buffers. However, the IO buffers can only be freed
after they have been dequeued and passed to the 'rx_callback()'. Since
this was only done by 'irq_handler()', we exhaust the slab allocator
under high TX load.
A fix for this is to process the RX queue not only in the IRQ handler
but also when transmitting packets.
genodelabs/genode#4555
m/udelay is called with closed interrupts. Linux contrib code expects no
other task to be run respectively to be re-scheduled. usleep_range leads to
executing other tasks, which causes assertions in "spinlock taken twice" or
"unexpected preempt count" errors, seen on runtime with wifi_drv and intel_fb.
The assertion triggered with the changes by #4562.
On okl4, pistachio, sel4 the test didn't come up fast enough in order to still
experience the first configuration of NIC router #1. This commit doubles the
lifetime of the first configuration of NIC router #1 to 4 seconds and raises
the overall test timeout accordingly.
Ref #4555
* Move common SMP and NO_HZ_IDLE variables and functions into
generic lx_emul shadow implementations, and integrate them
into the common lx_emul import rules
* Enable SMP and NO_HZ_IDLE within virt_linux kernel configuration
* Adapt pc drivers and wireguard accordingly
* Use original Linux softirq implementation in wireguard
* Remove erroneous softirq shadow implementation
Ref genodelabs/genode#4540
Ref genodelabs/genode#4562
In overload situations, i.e. when a sender fills up the entire buffer, we land
in situations where the sender receives an ack_avail signal, releases one
packet, allocates and sends a packet and fails to allocate a second packet.
This is especially relevant if the receiver does not batch ack_avail signals
(such as vfs_lwip). In those ping-pong scheduling scenarios, the overhead from
catching the Packet_alloc_failed exception becomes significant. In case of the
NIC router, we will land in an overload situation if the sender is faster than
the receiver. The packet buffer will be filled up at some point and the NIC
router starts to drop packets. For every dropped packet, we currently have to
catch the Packet_alloc_failed exception.
This commit adds a new method alloc_packet_attempt to Packet_stream_source that
has almost the same signature as the older alloc_packet method but returns
an Attempt<Packet_descriptor, Alloc_packet_error> object. As the method already
used the allocator back end exception-less, changes on lower levels were not
needed. Furthermore, the NIC router was modified to use the new exception-less
alloc_packet_attempt instead of alloc_packet.
Ref #4555
Replaces the former implementation of the 'find_by_ip' method at the data
structure for ARP cache entries. This method used to return a reference to the
found object and threw an exception if no matching object was found.
The new implementation doesn't return anything and doesn't throw exceptions. It
takes two lambda arguments instead. One for handling the case that a match was
found with a reference to the matching object as argument and another for
handling the case that no object matches.
This way, expensive exception handling can be avoided and object references
stay in a local scope.
Ref #4555
According to a benchmarking series on Zynq (base-hw) and x260 (base-nova) using
test-nic_perf_router, increasing the 'max_packets_per_signal' has a significant
effect on the packet throughput. By increasing the default value from 32
to 150, we could gain a few hundred Mbit/s. Increasing the value further
does not seem to have such a strong effect, though.
genodelabs/genode#4555
The checksums for forwarded/routed UDP, TCP and ICMP, used to be always
re-calculated from scratch in the NIC router although the router changes only
a few packet fields. This commit replaces the old approach whereever sensible
with an algorithm for incremental checksum updates suggested in RFC 1071.
The goal is to improve router performance.
Ref #4555
The checksums for forwarded/routed IPv4, used to be always re-calculated from
scratch in the NIC router although the router changes only a few packet fields.
This commit replaces the old approach whereever sensible with an algorithm for
incremental checksum updates suggested in RFC 1071. The goal is to improve
router performance.
Ref #4555
We used to use 'unsigned long' for the accumulating variable when calculating
internet checksums. However, 'signed long' is more in accordance with RFC 1071
and will allow us to share the same back end for folding, once we implement
incremental updating of internet checksums.
Ref #4555
Prevent public reflection of the only internally used 'init_sum' argument in
'uint16_t internet_checksum(...)' that, in addition, added a default value to
the function interface.
Ref #4555
When sending an ICMP ECHO reply, the router merely swaps SRC and DST of the
IPv4 header of the corresponding request and these changes cancel each other
out in checksum calculation. Therefore, with this commit, the router skips
updating the IPv4 checksum in this context.
Ref #4555
The router used to update IPv4 checksums when routing via an <ip> rule
despite the fact that it doesn't change any IPv4 header fields in this case.
Ref #4555
The NIC router used to update IPv4 and layer 4 checksums of a packet for each
interface it was sent to (say, all interfaces of the domain the packet was
routed to). However, there was and is no technical reason for not doing it
only once and then iterating over the interfaces with the already updated
packet. This is what this commit does in an intent to raise the router's
performance.
Ref #4555
The NIC router uses the timer for relatively coarse-grained timeouts.
It therefore suffices to update and store the current time when the NIC router
is signalled and use the cached time instead. This prevents frequent
syscalls or RPCs when acquiring the current time for every packet.
genodelabs/genode#4555
The link dissolve timeout is updated for every packet, which leads to
trigger_once() RPCs that only marginally change the scheduled timeout but
significantly slow down the packet throughput.
genodelabs/genode#4555
The wakeup call only emits a single signal as it assumed both are
handled by the same signal handler. However, the original implementation
did not reset the wakeup_needed variable properly.
genodelabs/genode#4555
When using signal batching, ack_avail and packet_avail should always
be emitted and preferred over ready_to_submit and ready_to_ack.
A signal receiver might decide to not register the ready_to_* signals when it
handles congestion by dropping packets. The Nic router is an example of
such a signal receiver.
genodelabs/genode#4555
Enables symetric-multi-processor support in the Linux kernel configuration
used as base for the driver ports for PC. This is done to be compliant with
common usage of x86 drivers today.
Moreover, this commit uses the original kernel source for softirq/tasklet
implementation to get rid of the insufficient shadow implementation
in the lx_emul sources.
Ref genodelabs/genode#4562
Prepare shadow implementations in spinlocks, pagetable defines,
and irq_stack assembler macros to be able to enable SMP on x86/PC.
Ref genodelabs/genode#4562
The test runs as lx_user task and uses several *delay and wait queue test
cases happened to be used in real ported linux drivers. The test shows
the time spent with several time sources, e.g. jiffies, rdtsc,
lx_time_counter_count etc.
Issue #4540
Use common implementation used by wifi and (not merged) audio driver.
Avoid usage of lib/delay.c since lpj and loop_for_jiffies are not calibrated
for the ported drivers as done on native Linux during boot and leads to wrong
delays for usb and intel_fb.
Issue #4540
Using the 'query_buffer_ppgtt()' function allows for retrieving the
virtual address of the buffer in the PPGTT.
This is for components that manage the GPU virtual addresses rather than
the client as is the case with the lima driver.
Issue #4559.
Adhere to include/linux/rcutiny.h behaviour, which sets the max timeout
for rcu_needs_cpu. Without the commit, in the most cases the timeout value
is zero (or random since the pointer is on stack uninitialized), which leads
to programming very short timeouts again and again, making the system never
idle.
Issue #4540
The box layout evenly distributes the child widgets according to the
number of children. This is not desired in the special case where a
child widget has a size of zero. The patch changes the layout algorithm
such that zero-sized widgets are not taken into account for distributing
residual space.
This patch replaces the former implicit "phonyness" of the rule by an
explicit .PHONY and installs a symlink from the target's build directory
to bin/ as is the usual practice for regular targets.
Related to issue #3972
The parent-provides model is destroyed if no <parent-provides> node is
found in the configuration, which resulted in
Warning: list model not empty at destruction time
and leaking memory for the allocated nodes. The commit now explicitly
empties the list model in the destructor of ~Parent_provides_model.
Note, the case is implicitly tested in pkg/test-init by step "denial of
forwarded session request" and <init_config version="empty">.
Thanks to Peter for reporting this issue.
Fixes#4547
Whenever a domain looses all its interfaces or the link state of all attached
interfaces is down at once, the domain potentially moves to another Ethernet
segment and should therefore consider its ARP cache to be outdated.
RFC 826 states that "... If a host moves, any connections initiated by that
host will work, assuming its own address resolution table is cleared when it
moves. ...".
Therefore, this commit introduces clearing the ARP cache and the initially
stated events.
This commit was motivated by an issue with the PinePhone Modem and USB NIC.
On the PinePhone, the Modem has its own OS and acts as direct gateway to the
outer world for the USB NIC that is driven by Genode. However, whenever the
Modem gets restarted, Modem and USB NIC receive a new MAC address. This used
to conflict with the NIC routers ARP entry for the Modem that didn't cease to
be valid.
With this commit, the integrator of such a scenario at least has a convenient
way of fixing this by ensuring that all interfaces at the USB NIC domain go
down when resetting (e.g. by ensuring that the USB NIC is the only interface at
that domain).
Fixes#4558
When creating a socket, fd flags can be specified by ORing them with the
socket type. Most importantly, the flag SOCK_NONBLOCK must be propagated
to the Socket_fs::Context in order to support non-blocking recv/send.
genodelabs/genode#4550
The 'iput()' function is called from '__sock_release()' when the sock
object has no valid file object. The release function on the other hand
is called when the supplicant closes a socket.
Fixes #xxx.
Replaces the former use of the 'find_by_name' method of the AVL string tree.
This method returned a reference to the found object and threw an exception if
no matching object was found.
The locally implemented replacement doesn't return anything and doesn't throw
exceptions. It takes two lambda arguments instead. One for handling the case
that a match was found with a reference to the matching object as argument and
another for handling the case that no object matches.
This way, expensive exception handling can be avoided and object references
stay in a local scope.
Furthermore, this commit modifies the local wrapper for the insert method of
the AVL string tree, so, that it follows the above mentioned concept as well.
Ref #4536
Replaces the former implementation of the 'find_by_domain' method at the data
structure for NAT rules. This method used to return a reference to the found
object and threw an exception if no matching object was found.
The new implementation doesn't return anything and doesn't throw exceptions. It
takes two lambda arguments instead. One for handling the case that a match was
found with a reference to the matching object as argument and another for
handling the case that no object matches.
This way, expensive exception handling can be avoided and object references
stay in a local scope.
Ref #4536
Replaces the former implementation of the 'find_by_port' method at the data
structure for permit rules. This method used to return a reference to the found
object and threw an exception if no matching object was found.
The new implementation doesn't return anything and doesn't throw exceptions. It
takes two lambda arguments instead. One for handling the case that a match was
found with a reference to the matching object as argument and another for
handling the case that no object matches.
This way, expensive exception handling can be avoided and object references
stay in a local scope.
Furthermore, the commit introduces a convenience wrapper for finding the best
matching pair of transport rule and corresponding permit rule for a given
destination IP and port. This method as well follows the above mentioned
concept.
Ref #4536
Replaces the former implementation of the 'find_longest_prefix_match' method at
the data structure for direct rules. This method used to return a reference to
the found object and threw an exception if no matching object was found.
The new implementation doesn't return anything and doesn't throw exceptions. It
takes two lambda arguments instead. One for handling the case that a match was
found with a reference to the matching object as argument and another for
handling the case that no object matches.
This way, expensive exception handling can be avoided and object references
stay in a local scope.
Ref #4536
Replaces the former implementation of the 'find_longest_prefix_match' method at
the data structure for direct rules. This method used to return a reference to
the found object and threw an exception if no matching object was found.
The new implementation doesn't return anything and doesn't throw exceptions. It
takes two lambda arguments instead. One for handling the case that a match was
found with a reference to the matching object as argument and another for
handling the case that no object matches.
This way, expensive exception handling can be avoided and object references
stay in a local scope.
Ref #4536
Replaces the former implementation of find_by_id at the data structure for
links. This method used to return a reference to the found object and threw an
exception if no matching object was found.
The new implementation doesn't return anything and doesn't throw exceptions. It
takes two lambda arguments instead. One for handling the case that a match was
found with a reference to the matching object as argument and another for
handling the case that no object matches.
This way, expensive exception handling can be avoided and object references
stay in a local scope.
Ref #4536
The 'with_libc' call at this point is not necessary and could be
harmful as it forces the usage of the user stack for the driver.
All code depending on this distinction should only be executed
from within the pthread.
Issue #4537.
Querying the RFKILL state led to execution of the Lx_kit::scheduler by
the pthread running the wpa_supplicant. As this may not happen the
RFKILL state is now solely managed by the driver and only the cached
state is read by the supplicant.
Fixes#4537.
Just add riscv spec files. The riscv versions should use MMIO transport
as ARM versions do. They also should work fine for riscv_qemu machine
from genode-riscv repository.
To not integrate referenced depot packages when building a sculpt image,
just set the environment variable DEPOT= to be empty. This allows to produce
slim images to the price that you have to publish the packages yourself.
In that case the sculpt run-script reminds you, and prints the package
versions.
Fixgenodelabs/genode#4530
Make it configurable, whether on a hotplug event the current valid Genode
config for the driver will be re-evaluated. By default it will be re-evaluated.
Issue #4531
On connector unplug the overall resolution of all available active connectors
can shrink and must be considered to potentially re-create the Capture
connection with smaller resolution size. Additionally, update the documentation.
Issue #4531
acpica and the Intel display driver tries to use the Intel Opregion
simultaneously on Genode, which is not supported nor wanted for IO_MEM region as
which it is handled.
Attempts to remove the access to the region was not successful, since some
SSDT table contains ACPI AML code which is executed regularly and read/write
the Opregion.
The patch adds support to read in a copy of the Intel Opregion done by the
acpi_drv component. The copy was sufficient to make the Intel display driver
working to find and lookup the Intel VBT (video bios table) information to
setup all connectors on a Fujitsu U7411 docking station.
Fixes#4531
acpica and the Intel display driver tries to use the Intel Opregion
simultaneously on Genode, which is not supported nor wanted for IO_MEM region as
which it is handled.
Attempts to remove the access to the region was not successful, since some
SSDT table contains ACPI AML code which is executed regularly and read/write
the Opregion.
The patch adds support to make a copy of the Intel Opregion and report it as
is. The copy was sufficient to make the Intel display driver working to find
and lookup the Intel VBT (video bios table) information to setup all
connectors on a Fujitsu U7411 docking station.
Issue #4531
ACPICA needs access to the host bridge 0:0.0 on Intel, which is also
accessed by the Intel display driver. Since for the Intel display driver the
PCI device is specified in the policy explicitly, the PCI device is filtered
out for the ACPICA driver which uses the policy "ALL".
Issue #4532
This commit introduces a hypervisor calling interface. The host kernel can
use it to either switch to a guest VM, or to invalidate the TLB with
regard to a specified VM id.
The VM-specific TLB invalidation is called whenever a VM (Vcpu)
gets destroyed.
Fixgenodelabs/genode#4528
When a PD gets deleted check whether it is active on the current CPU resp. MMU.
If yes, switch to core/kernel's PD to prevent that invalid page-tables or
address-space IDs are still in use. Moreover, whenever we switch to an idle
thread, we switch to kernel/core's PD too. Thereby, we prevent that vanished
PDs are still active on CPUs different from the one, where the core entrypoint
is active, which does the PD deletion.
This whole scheme is only valid under the assumption that core has only one
entrypoint running on one CPU.
Fixgenodelabs/genode#4527
Do not only distinguish core and user threads, but the idle threads too.
Instead of a boolean value, introduce a new thread type.
Ref genodelabs/genode#4527
All access to PCI devices can be handled nowadays via the platform session.
The I/O port access seems also to work not properly on newer UEFI machines.
Fixes#4532
As accommodating the session component object is already taken care of
be the root component implementation, remove the remaining redundant
checks.
Fixes#4521.
Since unblocking the pthread directly may lead to corruption we need
to post-pone it. So we send a signal that should be handled by the EP
after the EP has finished its current line of work.
Fixes#4523.
Instead of allocating the stack via 'kmalloc' point it to the actual
stack used by the task. This addresses issues with the USB
host-controller driver where sometimes hub port enumeration is not
working.
Fixes#4522.
We locally disable 'address-of-packed-member' warnings because GCC complained
about possible alignment issues when returning a reference to a packed member
as naturally aligned pointer (for some reason only on arm_v8a). We know that
the member is aligned to NETDEV_ALIGN via __attribute__ and that the warning
is therefor unnecessary.
Ref #4519
We have to correct the CC_OPT_* variable for these files and used to do so via
phony pre-requisite for the corresponding object files because the correction
had to take place after the variable initialization in
import-lx_emul_common.inc and before the creation of the object files. However,
this caused the objects to always rebuild.
This commit fixes this issue by using Make's feature of target-specific
variables instead. The drawback of this solution is that we can no longer
override CC_OPT_* with a modification of its original value but instead have to
override with a completely new value. This is because otherwise, Make would
either complain about recursive assignment or produce an empty value.
Ref #4519
The strict conversion warnings were disabled during development when the
contrib code was still compiled with the wireguard lib. Now this isn't
necessary anymore as the contrib code is in the wireguard_lx_inc_dirs lib.
Ref #4520
With this commit, the WireGuard component exits with a descriptive uncaught
exception on invalid configurations or when the user attempts to re-configure
attributes that are not re-configurable (private_key, listen_port, interface).
This is particularly important when it comes to the not re-configurable private
key. If the component would just ignore the attempt to override the private
key, the user may come to believe that his old (potentially compromised)
private key is not in use anymore.
The fact that the component now exits instead shouldn't be a problem, as the
user would have to restart the component anyway in order to apply the new
attribute values.
The commit also extends the wg_reconfig run script to test that WireGuard
exits on the attempt to re-configure the private key.
Ref #4520
Support removing peers by removing them from the component configuration.
This commit also introduces the wg_reconfig run script that tests adding and
removing single peers.
Ref #4520
I used to set the peer flags to 2 when adding a peer but merely because I
observed that value in my reference Linux. I now found that the flag 1<<1 means
'WGPEER_F_REPLACE_ALLOWEDIPS' and is ignored whenever the peer is new. Anyway,
I keep setting the flag but with the clearer enum name because the wg tool is
doing it as well when adding new peers and we want to stay close to how the
original code interacts.
Ref #4520
Build description files that feature both an actual target and
CUSTOM_TARGET_DEPS happen to re-link the target each time whenever one
of the CUSTOM_TARGET_DEPS is phony, e.g., gems/src/app/menu_view/.
The re-linking of the actual target is of course not desired. By
triggering the creation of CUSTOM_TARGET_DEPS from 'all:' instead of
'$(TARGET)', the specified files do not implicitly become link
dependencies of the target.
Issue #3972
The extra definition introduced by commit:
"lx_emul & arm: define ZERO_PAGE" re-defined the macro included
by a header of the contrib sources. This commit removes the
contrib header and defines thereby missing macros.
Fixes wrong atomic_*(ptr) usage with u32 pointer introduced by
commit "lx_emul: eliminate wrong include pathes". Atomic read or
write is nt needed in our case, we always schedule cooperatively.
Since "Consolidate USB test run-scripts" usb_hid_raw.run depends on
depot archives. Therefore, '--depot-dir' and '--depot-user' must be
passed to the nested run tool to cover cases that customize the depot
(e.g., our nightly CI).
Issue #4511
Introduces the pkg/wireguard archive that depends on the new src/wireguard
archive and deploys one WireGuard component with an empty configuration (can
be configured by the user via a launcher, for instance).
Fixed#4519
Introduce an arch-specific wireguard lib that contains all code from the
former arch-specific target.mk files. This allows us to create a generic
target.mk that merely depends on the library and a dummy.cc file. The latter
ensures that building/linking of the target isn't skipped by the build system.
Ref #4519
The wireguard library's purpose is having a separate INC_DIR setting for the
files that need Linux include paths that would clash with Genode include paths.
Therefore, the name wireguard_lx_inc_dirs is more descriptive. Furthermore,
this allows us to create a new arch-specific wireguard lib in a future commit
in the course of preventing arch-specific target.mk's (a commonly used
approach in Genode).
Ref #4519
