The scheduler has historically had an API where an application can
inform the kernel that it will never create a thread that can be
preempted, and the kernel and architecture layer would use that as an
optimization hint to eliminate some code paths.
Those optimizations have dwindled to almost nothing at this point, and
they're now objectively a smaller impact than the special casing that
was required to handle the idle thread (which, obviously, must always
be preemptible).
Fix this by eliminating the idea of "cooperative only" and ensuring
that there will always be at least one preemptible priority with value
>=0. CONFIG_NUM_PREEMPT_PRIORITIES now specifies the number of
user-accessible priorities other than the idle thread.
The only remaining workaround is that some older architectures (and
also SPARC) use the CONFIG_PREEMPT_ENABLED=n state as a hint to skip
thread switching on interrupt exit. So detect exactly those platforms
and implement a minimal workaround in the idle loop (basically "just
call swap()") instead, with a big explanation.
Note that this also fixes a bug in one of the philosophers samples,
where it would ask for 6 cooperative priorities but then use values -7
through -2. It was assuming the kernel would magically create a
cooperative priority for its idle thread, which wasn't correct even
before.
Fixes#34584
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
This adds the necessary bits for linker scripts and source code
to specify which symbols need to be pinned in memory. This is
needed for demand paging as some functions and data must reside
in memory all the time and cannot be paged out (e.g. paging,
scheduler, and interrupt routines for functionality).
This is up to the arch/SoC/board to define the sections in
their linker scripts as the pinned section may need special
alignment which cannot be done in common script snippets.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
This adds the necessary bits for linker scripts and source code
to specify which symbols are needed for boot process so they
can be grouped together.
One use of this is to group boot related code and data so these
won't interval with other kernel and application for better
caching.
This is a must for demand paging as some functions and data
must be available during the boot process and before the memory
manager is initialized. During this time, paging cannot be used
so symbols linked in virtual memory space are unavailable.
This is up to the arch/SoC/board to define the sections in
their linker scripts as section may need special alignment
which cannot be done in common script snippets.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
Remove the config BOOT_TIME_MEASUREMENT and corresponding #ifdef'd code
throughout (kernel/init.c, idle.c, core/common.S , reset.S, ... ) which
hold the extern hooks for z_timestamp_main and z_timestamp_idle in the
removed boot_time test suite.
Signed-off-by: Jennifer Williams <jennifer.m.williams@intel.com>
_kernel struct can be used when multithreading is disabled.
In that case sched.c may not be compiled.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Due to the use of gperf to generate hash table for kobjects,
the addresses of these kobjects cannot change during the last
few phases of linking (especially between zephyr_prebuilt.elf
and zephyr.elf). Because of this, the gperf generated data
needs to be placed at the end of memory to avoid pushing symbols
around in memory. This prevents moving these generated blocks
to earlier sections, for example, pinned data section needed
for demand paging. So create placeholders for use in
intermediate linking to reserve space for these generated blocks.
Due to uncertainty on the size of these blocks, more space is
being reserved which could result in wasted space. Though, this
retains the use of hash table for faster lookup.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
This adds a new kconfig CONFIG_TIMING_FUNCTIONS_NEED_AT_BOOT so
that the timing subsystem can be initialized at boot, instead of
being #ifdef under thread runtime statistics. This will allow
other part of kernel and other subsystems to utilize the timing
functions.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
Add a 'U' suffix to values when computing and comparing against
unsigned variables and other related fixes of the same MISRA rule (10.4)
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
Initialize all device objects in a batch before invoking any code that
might try to reference data in them. This eliminates a race condition
enabled by the ability to resolve a device structure at build time,
and reference it from one device's initialization routine before the
device itself has been initialized.
While the device is pulled from the sys_init records rather than
static devices, all in-tree init_entry records that are associated
with devices are produced via Z_DEVICE_DEFINE(), so there should be no
static devices that would be missed by instead iterating over the
device records.
Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
Activating K_FP_REGS flags introduces stack memory
overhead for the main thread in Cortex-M architecture.
Several ARM platforms experience main thread stack
overflows when building with FPU_SHARING=y.
Enabling FPU sharing in main thread should not be
the default configuration. Users are welcome to
enable FP sharing on the main thread in the
application code, in main().
This reverts commit 8453a73ede.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
Page tables created at build time may not include the
gperf data at the very end of RAM. Ensure this is mapped
properly at runtime to work around this.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Page tables created at build time may not include the
gperf data at the very end of RAM. Ensure this is mapped
properly at runtime to work around this.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This patch activates FPU feature for main thread if FPU related
configs (FPU, FPU_SHARING) are enabled.
Signed-off-by: Katsuhiro Suzuki <katsuhiro@katsuster.net>
Move banner and boot delay handling out of init.c
The code for banner was all over the place in init.c making it
unreadable.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
Most of kernel files where declaring os module without providing
log level. Because of that default log level was used instead of
CONFIG_KERNEL_LOG_LEVEL.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
This uses the timing functions to gather execution cycles of
threads. This provides greater details if arch/SoC/board
uses timer with higher resolution.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
Zephyr SMP kernels need to be able to run on architectures with
incoherent caches. Naive implementation of synchronization on such
architectures requires extensive cache flushing (e.g. flush+invalidate
everything on every spin lock operation, flush on every unlock!) and
is a performance problem.
Instead, many of these systems will have access to separate "coherent"
(usually uncached) and "incoherent" regions of memory. Where this is
available, place all writable data sections by default into the
coherent region. An "__incoherent" attribute flag is defined for data
regions that are known to be CPU-local and which should use the cache.
By default, this is used for stack memory.
Stack memory will be incoherent by default, as by definition it is
local to its current thread. This requires special cache management
on context switch, so an arch API has been added for that.
Also, when enabled, add assertions to strategic places to ensure that
shared kernel data is indeed coherent. We check thread objects, the
_kernel struct, waitq's, timeouts and spinlocks. In practice almost
all kernel synchronization is built on top of these structures, and
any shared data structs will contain at least one of them.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
Fixes races where threads on another CPU are joining the
exiting thread, since it could still be running when
the joiners wake up on a different CPU.
Fixes problems where the thread object is still being
used by the kernel when the fn_abort() function is called,
preventing the thread object from being recycled or
freed back to a slab pool.
Fixes a race where a thread is aborted from one CPU while
it self-aborts on another CPU, that was currently worked
around with a busy-wait.
Precedent for doing this comes from FreeRTOS, which also
performs final thread cleanup in the idle thread.
Some logic in z_thread_single_abort() rearranged such that
when we release sched_spinlock, the thread object pointer
is never dereferenced by the kernel again; join waiters
or fn_abort() logic may free it immediately.
An assertion added to z_thread_single_abort() to ensure
it never gets called with thread == _current outside of an ISR.
Some logic has been added to ensure z_thread_single_abort()
tasks don't run more than once.
Fixes: #26486
Related to: #23063#23062
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Now that device_api attribute is unmodified at runtime, as well as all
the other attributes, it is possible to switch all device driver
instance to be constant.
A coccinelle rule is used for this:
@r_const_dev_1
disable optional_qualifier
@
@@
-struct device *
+const struct device *
@r_const_dev_2
disable optional_qualifier
@
@@
-struct device * const
+const struct device *
Fixes#27399
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Certain architectures, such as ARM Cortex-M require a custom
switch to main(), in case the case we build Zephyr without
support for multithreading (CONFIG_MULTITHREADING=n). So as
to keep the change to kernel/init.c as unintrusive as
possible, we install an ARCH-specific hook in z_cstart(),
which gets called for architectures that require this
customized switch to main() function.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This now takes a stack pointer as an argument with TLS
and random offsets accounted for properly.
Based on #24467 authored by Flavio Ceolin.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
- simplify dummy thread initialization to a kswap.h
inline function
- use the same inline function for both early boot and
SMP setup
- add a note on necessity of the dummy thread even if
a custom swap to main is implemented
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Several reviewers agreed that DT_HAS_NODE_STATUS_OKAY(...) was an
undesirable API for the following reasons:
- it's inconsistent with the rest of the DT_NODE_HAS_FOO names
- DT_NODE_HAS_FOO_BAR_BAZ(node) was agreed upon as a shorthand
for macros which are equivalent to
DT_NODE_HAS_FOO(node) && DT_NODE_HAS_BAR(node) &&
- DT_NODE_HAS_BAZ(node), and DT_HAS_NODE_STATUS_OKAY is an odd duck
- DT_NODE_HAS_STATUS(..., okay) was viewed as more readable anyway
- it is seen as a somewhat aesthetically challenged name
Replace all users with DT_NODE_HAS_STATUS(..., okay), which is
semantically equivalent.
This is mostly done with sed, but a few remaining cases were done by
hand, along with whitespace, docs, and comment changes. These special
cases include the Nordic SOC static assert files.
Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
C++ is documented to be supported in applications, so it should be
supported in SYS_INIT() functions run at the application init level.
Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
When the device driver model got introduced, there were no concept of
SYS_INIT() which can be seen as software service. These were introduced
afterwards and reusing the device infrastructure for simplicity.
However, it meant to allocate a bit too much for something that only
required an initialization function to be called at right time.
Thus refactoring the devices structures relevantly:
- introducing struct init_entry which is a generic init end-point
- struct deviceconfig is removed and struct device owns everything now.
- SYS_INIT() generates only a struct init_entry via calling
INIT_ENTRY_DEFINE()
- DEVICE_AND_API_INIT() generates a struct device and calls
INIT_ENTRY_DEFINE()
- init objects sections are in ROM
- device objects sections are in RAM (but will end up in ROM once they
will be 'constified')
It also generate a tiny memory gain on both ROM and RAM, which is nice.
Perhaps kernel/device.c could be renamed to something more relevant.
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Rename DT_HAS_NODE to DT_HAS_NODE_STATUS_OKAY so the semantics are
clear. As going forward DT_HAS_NODE will report if a NODE exists
regardless of its status.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Convert various DT_CCM_* macros to use DT_CHOSEN(zephyr_ccm) and
associated macros from devicetree.h.
We remove CCM references from cortex_a and cortex_r linker scripts as
its only a feature on Cortex-M STM32 SoCs.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Convert various DT_DTCM_* macros to use DT_CHOSEN(zephyr_dtcm) and
associated macros from devicetree.h.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Replace CONFIG_ENTROPY_NAME with DT_CHOSEN_ZEPHYR_ENTROPY_LABEL. We now
set zephyr,entropy in the chosen node of the device tree to the entropy
device.
This allows us to remove CONFIG_ENTROPY_NAME from dts_fixup.h. Also
remove any other stale ENTROPY related defines in dts_fixup.h files.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
This adds a sys init level which allows device and sys_init
to be done after SMP initialization, z_smp_init(), when all
cores are up and running.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
The set of interrupt stacks is now expressed as an array. We
also define the idle threads and their associated stacks this
way. This allows for iteration in cases where we have multiple
CPUs.
There is now a centralized declaration in kernel_internal.h.
On uniprocessor systems, z_interrupt_stacks has one element
and can be used in the same way as _interrupt_stack.
The IRQ stack for CPU 0 is now set in init.c instead of in
arch code.
The extern definition of the main thread stack is now removed,
this doesn't need to be in a header.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This function had a to sys_rand_get() even without random source. As
Zephyr is built with linkage garbage collection and this function is
called only if either ENTROPY_HAS_DRIVER or TEST_RANDOM_GENERATOR is
enabled and these options automatically enable a random source.
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
Use of the _current_cpu pointer cannot be done safely in a preemptible
context. If a thread is preempted and migrates to another CPU, the
old CPU record will be wrong.
Add a validation assert to the expression that catches incorrect
usages, and fix up the spots where it was wrong (most important being
a few uses of _current outside of locks, and the arch_is_in_isr()
implementation).
Note that the resulting _current expression now requires locking and
is going to be somewhat slower. Longer term it's going to be better
to augment the arch API to allow SMP architectures to implement a
faster "get current thread pointer" action than this default.
Note also that this change means that "_current" is no longer
expressible as an lvalue (long ago, it was just a static variable), so
the places where it gets assigned now assign to _current_cpu->current
instead.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>