While the LOCKED pattern is universally useful it can be misused. This
change therefore exposes the LOCKED pattern with extensive usage
documentation to reduce the risk of abuse or unintended deadlock.
Signed-off-by: Florian Grandel <fgrandel@code-for-humans.de>
Device dependencies are not always required, so make them optional via
CONFIG_DEVICE_DEPS. When enabled, the gen_device_deps script will run so
that dependencies are collected and part of the final image. Related
APIs will be also made available. Since device dependencies are used in
just a few places (power domains), disable the feature by default. When
not enabled, a second linking pass will not be required.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
Rename struct device `handles` member to `deps`, in line with previous
renamings in the device API.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
The switch_handle field in the thread struct is used as an atomic flag
between CPUs in SMP, and has been known for a long time to technically
require memory barriers for correct operation. We have an API for
that now, so put them in:
* The code immediately before arch_switch() needs a write barrier to
ensure that thread state written by the scheduler is seen to happen
before the outgoing thread is flagged with a valid switch handle.
* The loop in z_sched_switch_spin() needs a read barrier at the end,
to make sure the calling context doesn't load state from before the
other CPU stored the switch handle.
Also, that same spot in switch_spin was spinning with interrupts held,
which means it needs a call to arch_spin_relax() to avoid a FPU state
deadlock on some architectures.
Signed-off-by: Andy Ross <andyross@google.com>
This trick turns out also to be needed by the abort/join code.
Promote it to a more formal-looking internal API and clean up the
documentation to (hopefully) clarify the exact behavior and better
explain the need.
This is one of the more... enchanted bits of the scheduler, and while
the trick is IMHO pretty clean, it remains a big SMP footgun.
Signed-off-by: Andy Ross <andyross@google.com>
z_page_frame can't be packed on Xtensa due memory alignment
constraints. When this is struct is packed it is 5 bytes long it will
cause an memory alignment problem on Xtensa.
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
Removes unused absolute symbols that are defined via the
GEN_ABSOLUTE_SYM() macro in the kernel directory.
Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>
Rework the fragile and ad-hoc computation of timeslice expirations
into per-CPU struct _timeout objects with regular callbacks. The
expiration callbacks themselves simply set a per-cpu flag (they might
run on any CPU), which gets checked at the end of the timer ISR on
every CPU.
This simplifies logic and removes a bunch of code. It also fixes at
least three bugs:
1. As @npitre discovered: On SMP, the number of ticks announced on any
given CPU is going to be a subset of all expired ticks. This broke
the accounting of timeslice ticks, and effectively meant that
timeslicing only worked on SMP on systems where one CPU could hog all
the announcements, and only on that CPU.
2. The bootstrap path to arm the timer driver after setting the first
timeout in an empty list couldn't take into account
sys_clock_elapsed() ticks, as it didn't know whether it was being
called underneath an existing announce loop. Now this code is no
longer responsible for knowing anything about time slicing at all.
3. Also on SMP, there was a case where two CPUs timeslicing
simultaneously could stomp on each others' timeouts in
z_set_timeout_expiry(), as neither had a way of knowing what the
other's state was. CPUs could miss their own expiration and have to
wait for the slice expiration on the other CPU. Now, timeouts are
global objects with simple expiration times, and there's no need for
that function at all.
Signed-off-by: Andy Ross <andyross@google.com>
Some of the offset symbols that are derived from the macro
GEN_OFFSET_SYM() are not used anywhere in the Zephyr codebase.
Remove them as part of a cleanup effort.
Instances of an associated GEN_OFFSET_SYM() have also been
removed when the resulting macro is no longer referenced.
Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>
Some of the offset symbols generated via the macro GEN_OFFSET_SYM()
are not used anywhere in the Zephyr codebase. Remove them as part of
a cleanup effort.
Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>
Adds a routine to safely walk a specified wait queue and invoke a
custom callback function on each waiting thread.
Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>
The interrupt stack is used as the system stack during kernel
initialization while IRQs are not yet enabled. The sp register is
set to z_interrupt_stacks + CONFIG_ISR_STACK_SIZE.
CONFIG_ISR_STACK_SIZE only represents the desired usable stack size.
This does not take into account the added guard area. Result is a stack
whose pointer is much closer to the trigger zone than expected when
CONFIG_PMP_STACK_GUARD=y, and the SMP configuration in particular pushes
it over the edge during many CI test cases.
Worse: during early init we're not quite ready to handle exceptions
yet and complete havoc ensues with no meaningful debugging output.
Make sure the early assembly code locates the actual top of the stack
by generating a constant with its true size.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Fixes#46324
Set dummy_thread->base.slice_ticks to 0 when
CONFIG_TIMESLICE_PER_THREAD is set. To avoid
_current_cpu->slice_ticks be a big number.
Signed-off-by: Hu Zhenyu <zhenyu.hu@intel.com>
MISRA C:2012 Rule 14.4 (The controlling expression of an if statement
and the controlling expression of an iteration-statement shall have
essentially Boolean type.)
Use `bool' instead of `int' to represent Boolean values.
Use `do { ... } while (false)' instead of `do { ... } while (0)'.
Use comparisons with zero instead of implicitly testing integers.
This commit is a subset of the original commit:
5d02614e34a86b549c7707d3d9f0984bc3a5f22a
Signed-off-by: Simon Hein <SHein@baumer.com>
This commit updates all deprecated `K_KERNEL_PINNED_STACK_ARRAY_EXTERN`
macro usages to use the `K_KERNEL_PINNED_STACK_ARRAY_DECLARE` macro
instead.
Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
In order to bring consistency in-tree, migrate all kernel code to the
new prefix <zephyr/...>. Note that the conversion has been scripted,
refer to zephyrproject-rtos#45388 for more details.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
This adds lazy floating point context switching. On svc/irq entrance,
the VFP is disabled and a pointer to the exception stack frame is saved
away. If the esf pointer is still valid on exception exit, then no
other context used the VFP so the context is still valid and nothing
needs to be restored. If the esf pointer is NULL on exception exit,
then some other context used the VFP and the floating point context is
restored from the esf.
The undefined instruction handler is responsible for saving away the
floating point context if needed. If the handler is in the first
irq/svc context and the current thread uses the VFP, then the float
context needs to be saved. Also, if the handler is in a nested context
and the previous context was using the FVP, save the float context.
Signed-off-by: Bradley Bolen <bbolen@lexmark.com>
Instead of resizing all devices handles, we just resize devices that are
power domains. This means that a power domain has to be declared as
compatbile with "power-domain" in device tree node.
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
Zephyr's timeslice implementation has always been somewhat primitive.
You get a global timeslice that applies broadly to the whole bottom of
the priority space, with no ability (beyond that one priority
threshold) to tune it to work on certain threads, etc...
This adds an (optionally configurable) API that allows timeslicing to
be controlled on a per-thread basis: any thread at any priority can be
set to timeslice, for a configurable per-thread slice time, and at the
end of its slice a callback can be provided that can take action.
This allows the application to implement things like responsiveness
heuristics, "fair" scheduling algorithms, etc... without requiring
that facility in the core kernel.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
Zeroing the BSS and copying data to RAM with regular memset/memcpy may
cause problems when those functions are assuming a fully initialized
system for their optimizations to work e.g. some instructions require
an active MMU, but turning the MMU on needs the .bss section to be
cleared first, etc.
Commit c5b898743a ("aarch64: Fix alignment fault on z_bss_zero()")
provides a detailed explanation of such a case.
Replacing z_bss_zero() with an architecture specific one is problematic
as the former may see new sections added to it that would be missed by
the later. The same reasoning goes for z_data_copy().
Let's make maintenance much easier by providing weak versions of
memset/memcpy that can be overridden by architecture-specific safe
versions when needed.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
