User threads can only create other nonessential user threads
of equal or lower priority and must have access to the entire
stack area.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
We need to track permission on stack memory regions like we do
with other kernel objects. We want stacks to live in a memory
area that is outside the scope of memory domain permission
management. We need to be able track what stacks are in use,
and what stacks may be used by user threads trying to call
k_thread_create().
Some special handling is needed because thread stacks appear as
variously-sized arrays of struct _k_thread_stack_element which is
just a char. We need the entire array to be considered an object,
but also properly handle arrays of stacks.
Validation of stacks also requires that the bounds of the stack
are not exceeded. Various approaches were considered. Storing
the size in some header region of the stack itself would not allow
the stack to live in 'noinit'. Having a stack object be a data
structure that points to the stack buffer would confound our
current APIs for declaring stacks as arrays or struct members.
In the end, the struct _k_object was extended to store this size.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
It's currently too easy to run out of thread IDs as they
are never re-used on thread exit.
Now the kernel maintains a bitfield of in-use thread IDs,
updated on thread creation and termination. When a thread
exits, the permission bitfield for all kernel objects is
updated to revoke access for that retired thread ID, so that
a new thread re-using that ID will not gain access to objects
that it should not have.
Because of these runtime updates, setting the permission
bitmap for an object to all ones for a "public" object doesn't
work properly any more; a flag is now set for this instead.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This will allow these thread objects to be re-used.
_mark_thread_as_dead() removed, it was only being called in one
place.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Use some preprocessor trickery to automatically deduce the amount of
arguments for the various _SYSCALL_HANDLERn() macros. Makes the grunt
work of converting a bunch of kernel APIs to system calls slightly
easier.
Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>
By default, threads are created only having access to their own thread
object and nothing else. This new flag to k_thread_create() gives the
thread access to all objects that the parent had at the time it was
created, with the exception of the parent thread itself.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
We now have macros which should significantly reduce the amount of
boilerplate involved with defining system call handlers.
- Macros which define the proper prototype based on number of arguments
- "SIMPLE" variants which create handlers that don't need anything
other than object verification
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Use new _SYSCALL_OBJ/_SYSCALL_OBJ_INIT macros.
Use new _SYSCALL_MEMORY_READ/_SYSCALL_MEMORY_WRITE macros.
Some non-obvious checks changed to use _SYSCALL_VERIFY_MSG.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
We want applications to be able to enable and disable userspace without
changing any code. k_thread_user_mode_enter() now just jumps into the
entry point if CONFIG_USERSPACE is disabled.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Now creating a thread will assign it a unique, monotonically increasing
id which is used to reference the permission bitfield in the kernel
object metadata.
Stub functions in userspace.c now implemented.
_new_thread is now wrapped in a common function with pre- and post-
architecture thread initialization tasks.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
We already check the stack sentinel for outgoing thread when we _Swap,
just leverage that.
The thread state check in _check_stack_sentinel now only exits if the
current thread is a dummy thread.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Thread may be in user mode when it returns and can't look at
_current. Use k_current_get() which will be a system call.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
In various places, a private _thread_entry_t, or the full prototype
were being used. Be consistent and use the same typedef everywhere.
Signen-off-by: Andrew Boie <andrew.p.boie@intel.com>
Previously, this was only done if an essential thread self-exited,
and was a runtime check that generated a kernel panic.
Now if any thread has k_thread_abort() called on it, and that thread
is essential to the system operation, this check is made. It is now
an assertion.
_NANO_ERR_INVALID_TASK_EXIT checks and printouts removed since this
is now an assertion.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
It's now possible to instantiate a thread object, but delay its
execution indefinitely. This was already supported with K_THREAD_DEFINE.
A new API, k_thread_start(), now exists to start threads that are in
this state.
The intended use-case is to initialize a thread with K_USER, then grant
it various access permissions, and only then start it.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
All system calls made from userspace which involve pointers to kernel
objects (including device drivers) will need to have those pointers
validated; userspace should never be able to crash the kernel by passing
it garbage.
The actual validation with _k_object_validate() will be in the system
call receiver code, which doesn't exist yet.
- CONFIG_USERSPACE introduced. We are somewhat far away from having an
end-to-end implementation, but at least need a Kconfig symbol to
guard the incoming code with. Formal documentation doesn't exist yet
either, but will appear later down the road once the implementation is
mostly finalized.
- In the memory region for RAM, the data section has been moved last,
past bss and noinit. This ensures that inserting generated tables
with addresses of kernel objects does not change the addresses of
those objects (which would make the table invalid)
- The DWARF debug information in the generated ELF binary is parsed to
fetch the locations of all kernel objects and pass this to gperf to
create a perfect hash table of their memory addresses.
- The generated gperf code doesn't know that we are exclusively working
with memory addresses and uses memory inefficently. A post-processing
script process_gperf.py adjusts the generated code before it is
compiled to work with pointer values directly and not strings
containing them.
- _k_object_init() calls inserted into the init functions for the set of
kernel object types we are going to support so far
Issue: ZEP-2187
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Historically, stacks were just character buffers and could be treated
as such if the user wanted to look inside the stack data, and also
declared as an array of the desired stack size.
This is no longer the case. Certain architectures will create a memory
region much larger to account for MPU/MMU guard pages. Unfortunately,
the kernel interfaces treat both the declared stack, and the valid
stack buffer within it as the same char * data type, even though these
absolutely cannot be used interchangeably.
We introduce an opaque k_thread_stack_t which gets instantiated by
K_THREAD_STACK_DECLARE(), this is no longer treated by the compiler
as a character pointer, even though it really is.
To access the real stack buffer within, the result of
K_THREAD_STACK_BUFFER() can be used, which will return a char * type.
This should catch a bunch of programming mistakes at build time:
- Declaring a character array outside of K_THREAD_STACK_DECLARE() and
passing it to K_THREAD_CREATE
- Directly examining the stack created by K_THREAD_STACK_DECLARE()
which is not actually the memory desired and may trigger a CPU
exception
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
One of the stack sentinel policies was to check the sentinel
any time a cooperative context switch is done (i.e, _Swap is
called).
This was done by adding a hook to _check_stack_sentinel in
every arch's __swap function.
This way is cleaner as we just have the hook in one inline
function rather than implemented in several different assembly
dialects.
The check upon interrupt is now made unconditionally rather
than checking if we are calling __swap, since the check now
is only called on cooperative _Swap(). The interrupt is always
serviced first.
Issue: ZEP-2244
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This places a sentinel value at the lowest 4 bytes of a stack
memory region and checks it at various intervals, including when
servicing interrupts or context switching.
This is implemented on all arches except ARC, which supports stack
bounds checking directly in hardware.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Unline k_thread_spawn(), the struct k_thread can live anywhere and not
in the thread's stack region. This will be useful for memory protection
scenarios where private kernel structures for a thread are not
accessible by that thread, or we want to allow the thread to use all the
stack space we gave it.
This requires a change to the internal _new_thread() API as we need to
provide a separate pointer for the k_thread.
By default, we still create internal threads with the k_thread in stack
memory. Forthcoming patches will change this, but we first need to make
it easier to define k_thread memory of variable size depending on
whether we need to store coprocessor state or not.
Change-Id: I533bbcf317833ba67a771b356b6bbc6596bf60f5
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Adds event based scheduling logic to the kernel. Updates
management of timeouts, timers, idling etc. based on
time tracked at events rather than periodic ticks. Provides
interfaces for timers to announce and get next timer expiry
based on kernel scheduling decisions involving time slicing
of threads, timeouts and idling. Uses wall time units instead
of ticks in all scheduling activities.
The implementation involves changes in the following areas
1. Management of time in wall units like ms/us instead of ticks
The existing implementation already had an option to configure
number of ticks in a second. The new implementation builds on
top of that feature and provides option to set the size of the
scheduling granurality to mili seconds or micro seconds. This
allows most of the current implementation to be reused. Due to
this re-use and co-existence with tick based kernel, the names
of variables may contain the word "tick". However, in the
tickless kernel implementation, it represents the currently
configured time unit, which would be be mili seconds or
micro seconds. The APIs that take time as a parameter are not
impacted and they continue to pass time in mili seconds.
2. Timers would not be programmed in periodic mode
generating ticks. Instead they would be programmed in one
shot mode to generate events at the time the kernel scheduler
needs to gain control for its scheduling activities like
timers, timeouts, time slicing, idling etc.
3. The scheduler provides interfaces that the timer drivers
use to announce elapsed time and get the next time the scheduler
needs a timer event. It is possible that the scheduler may not
need another timer event, in which case the system would wait
for a non-timer event to wake it up if it is idling.
4. New APIs are defined to be implemented by timer drivers. Also
they need to handler timer events differently. These changes
have been done in the HPET timer driver. In future other timers
that support tickles kernel should implement these APIs as well.
These APIs are to re-program the timer, update and announce
elapsed time.
5. Philosopher and timer_api applications have been enabled to
test tickless kernel. Separate configuration files are created
which define the necessary CONFIG flags. Run these apps using
following command
make pristine && make BOARD=qemu_x86 CONF_FILE=prj_tickless.conf qemu
Jira: ZEP-339 ZEP-1946 ZEP-948
Change-Id: I7d950c31bf1ff929a9066fad42c2f0559a2e5983
Signed-off-by: Ramesh Thomas <ramesh.thomas@intel.com>
Unlike assertions, these APIs are active at all times. The kernel will
treat these errors in the same way as fatal CPU exceptions. Ultimately,
the policy of what to do with these errors is implemented in
_SysFatalErrorHandler.
If the archtecture supports it, a real CPU exception can be triggered
which will provide a complete register dump and PC value when the
problem occurs. This will provide more helpful information than a fake
exception stack frame (_default_esf) passed to the arch-specific exception
handling code.
Issue: ZEP-843
Change-Id: I8f136905c05bb84772e1c5ed53b8e920d24eb6fd
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Convert code to use u{8,16,32,64}_t and s{8,16,32,64}_t instead of C99
integer types. This handles the remaining includes and kernel, plus
touching up various points that we skipped because of include
dependancies. We also convert the PRI printf formatters in the arch
code over to normal formatters.
Jira: ZEP-2051
Change-Id: Iecbb12601a3ee4ea936fd7ddea37788a645b08b0
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
When CONFIG_FP_SHARING is enabled without CONFIG_LEGACY
thread.c was referencing symbols like K_TASK_GROUP_FPU
which are defined in legacy.h
Change-Id: I4bb1723f91c3e3586c5d1bf05cf23a1c0d3d5aac
Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
The K_<thread option> flags/options avaialble to users were hidden in
the kernel private header files: move them to include/kernel.h to
publicize them.
Also, to avoid any future confusion, rename the k_thread.execution_flags
field to user_options.
Change-Id: I65a6fd5e9e78d4ccf783f3304b607a1e6956aeac
Signed-off-by: Benjamin Walsh <walsh.benj@gmail.com>
The execution_flags will store the user-facing states of a thread.
This also fixes a bug where K_ESSENTIAL was already assigned to
execution_flags via the options field of
k_thread_spawn()/K_THREAD_DEFINE().
Change-Id: I91ad7a62b5d180e09eead8985ff519809959ecf2
Signed-off-by: Benjamin Walsh <walsh.benj@gmail.com>
Replace the existing Apache 2.0 boilerplate header with an SPDX tag
throughout the zephyr code tree. This patch was generated via a
script run over the master branch.
Also updated doc/porting/application.rst that had a dependency on
line numbers in a literal include.
Manually updated subsys/logging/sys_log.c that had a malformed
header in the original file. Also cleanup several cases that already
had a SPDX tag and we either got a duplicate or missed updating.
Jira: ZEP-1457
Change-Id: I6131a1d4ee0e58f5b938300c2d2fc77d2e69572c
Signed-off-by: David B. Kinder <david.b.kinder@intel.com>
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Some thread fields were 32-bit wide, when they are not even close to
using that full range of values. They are instead changed to 8-bit fields.
- prio can fit in one byte, limiting the priorities range to -128 to 127
- recursive scheduler locking can be limited to 255; a rollover results
most probably from a logic error
- flags are split into execution flags and thread states; 8 bits is
enough for each of them currently, with at worst two states and four
flags to spare (on x86, on other archs, there are six flags to spare)
Doing this saves 8 bytes per stack. It also sets up an incoming
enhancement when checking if the current thread is preemptible on
interrupt exit.
Change-Id: Ieb5321a5b99f99173b0605dd4a193c3bc7ddabf4
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>
Also remove mentions of unified kernel in various places in the kernel,
samples and documentation.
Change-Id: Ice43bc73badbe7e14bae40fd6f2a302f6528a77d
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
