Add a k_timeout_t type, and use it everywhere that kernel API
functions were accepting a millisecond timeout argument. Instead of
forcing milliseconds everywhere (which are often not integrally
representable as system ticks), do the conversion to ticks at the
point where the timeout is created. This avoids an extra unit
conversion in some application code, and allows us to express the
timeout in units other than milliseconds to achieve greater precision.
The existing K_MSEC() et. al. macros now return initializers for a
k_timeout_t.
The K_NO_WAIT and K_FOREVER constants have now become k_timeout_t
values, which means they cannot be operated on as integers.
Applications which have their own APIs that need to inspect these
vs. user-provided timeouts can now use a K_TIMEOUT_EQ() predicate to
test for equality.
Timer drivers, which receive an integer tick count in ther
z_clock_set_timeout() functions, now use the integer-valued
K_TICKS_FOREVER constant instead of K_FOREVER.
For the initial release, to preserve source compatibility, a
CONFIG_LEGACY_TIMEOUT_API kconfig is provided. When true, the
k_timeout_t will remain a compatible 32 bit value that will work with
any legacy Zephyr application.
Some subsystems present timeout (or timeout-like) values to their own
users as APIs that would re-use the kernel's own constants and
conventions. These will require some minor design work to adapt to
the new scheme (in most cases just using k_timeout_t directly in their
own API), and they have not been changed in this patch, instead
selecting CONFIG_LEGACY_TIMEOUT_API via kconfig. These subsystems
include: CAN Bus, the Microbit display driver, I2S, LoRa modem
drivers, the UART Async API, Video hardware drivers, the console
subsystem, and the network buffer abstraction.
k_sleep() now takes a k_timeout_t argument, with a k_msleep() variant
provided that works identically to the original API.
Most of the changes here are just type/configuration management and
documentation, but there are logic changes in mempool, where a loop
that used a timeout numerically has been reworked using a new
z_timeout_end_calc() predicate. Also in queue.c, a (when POLL was
enabled) a similar loop was needlessly used to try to retry the
k_poll() call after a spurious failure. But k_poll() does not fail
spuriously, so the loop was removed.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
Private type, internal to the kernel, not directly associated
with any k_object_* APIs. Is the return value of z_object_find().
Rename to struct z_object.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Rather than stuffing various values in a uintptr_t based on
type using casts, use a union for this instead.
No functional difference, but the semantics of the data member
are now much clearer to the casual observer since it is now
formally defined by this union.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Promote the private z_arch_* namespace, which specifies
the interface between the core kernel and the
architecture code, to a new top-level namespace named
arch_*.
This allows our documentation generation to create
online documentation for this set of interfaces,
and this set of interfaces is worth treating in a
more formal way anyway.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
z_set_thread_return_value is part of the core kernel -> arch
interface and has been renamed to z_arch_thread_return_value_set.
z_set_thread_return_value_with_data renamed to
z_thread_return_value_set_with_data for consistency.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
The semi-automated API changes weren't checkpatch aware. Fix up
whitespace warnings that snuck into the previous patches. Really this
should be squashed, but that's somewhat difficult given the structure
of the series.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
System call arguments, at the arch layer, are single words. So
passing wider values requires splitting them into two registers at
call time. This gets even more complicated for values (e.g
k_timeout_t) that may have different sizes depending on configuration.
This patch adds a feature to gen_syscalls.py to detect functions with
wide arguments and automatically generates code to split/unsplit them.
Unfortunately the current scheme of Z_SYSCALL_DECLARE_* macros won't
work with functions like this, because for N arguments (our current
maximum N is 10) there are 2^N possible configurations of argument
widths. So this generates the complete functions for each handler and
wrapper, effectively doing in python what was originally done in the
preprocessor.
Another complexity is that traditional the z_hdlr_*() function for a
system call has taken the raw list of word arguments, which does not
work when some of those arguments must be 64 bit types. So instead of
using a single Z_SYSCALL_HANDLER macro, this splits the job of
z_hdlr_*() into two steps: An automatically-generated unmarshalling
function, z_mrsh_*(), which then calls a user-supplied verification
function z_vrfy_*(). The verification function is typesafe, and is a
simple C function with exactly the same argument and return signature
as the syscall impl function. It is also not responsible for
validating the pointers to the extra parameter array or a wide return
value, that code gets automatically generated.
This commit includes new vrfy/msrh handling for all syscalls invoked
during CI runs. Future commits will port the less testable code.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
There's no need for a system call for this; futexes live in
user memory and the initialization bit is ignored.
It's sufficient to just do an atomic_set().
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
A k_futex is a lightweight mutual exclusion primitive designed
to minimize kernel involvement. Uncontended operation relies
only on atomic access to shared memory. k_futex structure lives
in application memory. And when using futexes, the majority of
the synchronization operations are performed in user mode. A
user-mode thread employs the futex wait system call only when
it is likely that the program has to block for a longer time
until the condition becomes true. When the condition comes true,
futex wake operation will be used to wake up one or more threads
waiting on that futex.
This patch implements two futex operations: k_futex_wait and
k_futex_wake. For k_futex_wait, the comparison with the expected
value, and starting to sleep are performed atomically to prevent
lost wake-ups. If different context changed futex's value after
the calling use-mode thread decided to block himself based on
the old value, the comparison will help observing the value
change and will not start to sleep. And for k_futex_wake, it
will wake at most num_waiters of the waiters that are sleeping
on that futex. But no guarantees are made on which threads are
woken, that means scheduling priority is not taken into
consideration.
Fixes: #14493.
Signed-off-by: Wentong Wu <wentong.wu@intel.com>
Andy Ross