zephyr/arch/arm/core/thread.c

158 lines
5.0 KiB
C

/* thread.c - new thread creation for ARM Cortex-M */
/*
* Copyright (c) 2013-2014 Wind River Systems, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1) Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2) Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3) Neither the name of Wind River Systems nor the names of its contributors
* may be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
DESCRIPTION
Core nanokernel fiber related primitives for the ARM Cortex-M processor
architecture.
*/
#include <nanokernel.h>
#include <arch/cpu.h>
#include <toolchain.h>
#include <nano_private.h>
#include <wait_q.h>
#ifdef CONFIG_INIT_STACKS
#include <string.h>
#endif /* CONFIG_INIT_STACKS */
tNANO _nanokernel = {0};
#if defined(CONFIG_THREAD_MONITOR)
#define THREAD_MONITOR_INIT(tcs) _thread_monitor_init(tcs)
#else
#define THREAD_MONITOR_INIT(tcs) \
do {/* do nothing */ \
} while ((0))
#endif
#if defined(CONFIG_THREAD_MONITOR)
/**
*
* @brief Initialize thread monitoring support
*
* Currently only inserts the new thread in the list of active threads.
*
* @return N/A
*/
static ALWAYS_INLINE void _thread_monitor_init(struct tcs *tcs /* thread */
)
{
unsigned int key;
/*
* Add the newly initialized thread to head of the list of threads. This
* singly linked list of threads maintains ALL the threads in the system:
* both tasks and fibers regardless of whether they are runnable.
*/
key = irq_lock();
tcs->next_thread = _nanokernel.threads;
_nanokernel.threads = tcs;
irq_unlock(key);
}
#endif /* CONFIG_THREAD_MONITOR */
/**
*
* @brief Intialize a new thread from its stack space
*
* The control structure (TCS) is put at the lower address of the stack. An
* initial context, to be "restored" by __pendsv(), is put at the other end of
* the stack, and thus reusable by the stack when not needed anymore.
*
* The initial context is an exception stack frame (ESF) since exiting the
* PendSV exception will want to pop an ESF. Interestingly, even if the lsb of
* an instruction address to jump to must always be set since the CPU always
* runs in thumb mode, the ESF expects the real address of the instruction,
* with the lsb *not* set (instructions are always aligned on 16 bit halfwords).
* Since the compiler automatically sets the lsb of function addresses, we have
* to unset it manually before storing it in the 'pc' field of the ESF.
*
* <options> is currently unused.
*
* @return N/A
*/
void _new_thread(
char *pStackMem, /* aligned stack memory */
unsigned stackSize, /* stack size in bytes */
_thread_entry_t pEntry, /* entry point */
void *parameter1, /* entry point first param */
void *parameter2, /* entry point second param */
void *parameter3, /* entry point third param */
int priority, /* thread priority (-1 for tasks) */
unsigned options /* misc options (future) */
)
{
char *stackEnd = pStackMem + stackSize;
struct __esf *pInitCtx;
struct tcs *tcs = (struct tcs *) pStackMem;
#ifdef CONFIG_INIT_STACKS
memset(pStackMem, 0xaa, stackSize);
#endif
/* carve the thread entry struct from the "base" of the stack */
pInitCtx = (struct __esf *)(STACK_ROUND_DOWN(stackEnd) -
sizeof(struct __esf));
pInitCtx->pc = ((uint32_t)_thread_entry) & 0xfffffffe;
pInitCtx->a1 = (uint32_t)pEntry;
pInitCtx->a2 = (uint32_t)parameter1;
pInitCtx->a3 = (uint32_t)parameter2;
pInitCtx->a4 = (uint32_t)parameter3;
pInitCtx->xpsr =
0x01000000UL; /* clear all, thumb bit is 1, even if RO */
tcs->link = NULL;
tcs->flags = priority == -1 ? TASK | PREEMPTIBLE : FIBER;
tcs->prio = priority;
#ifdef CONFIG_THREAD_CUSTOM_DATA
/* Initialize custom data field (value is opaque to kernel) */
tcs->custom_data = NULL;
#endif
tcs->preempReg.psp = (uint32_t)pInitCtx;
tcs->basepri = 0;
_nano_timeout_tcs_init(tcs);
/* initial values in all other registers/TCS entries are irrelevant */
THREAD_MONITOR_INIT(tcs);
}