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/**
* @file
*
* @brief Allocate and Initialize Per CPU Structures
* @ingroup PerCPU
*/
/*
* COPYRIGHT (c) 1989-2011.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/score/percpu.h>
#include <rtems/score/assert.h>
#include <rtems/score/smpimpl.h>
#include <rtems/config.h>
#if defined(RTEMS_SMP)
static SMP_lock_Control _Per_CPU_State_lock =
SMP_LOCK_INITIALIZER("per-CPU state");
static void _Per_CPU_State_busy_wait(
const Per_CPU_Control *cpu,
Per_CPU_State new_state
)
{
Per_CPU_State state = cpu->state;
switch ( new_state ) {
case PER_CPU_STATE_REQUEST_START_MULTITASKING:
while (
state != PER_CPU_STATE_READY_TO_START_MULTITASKING
&& state != PER_CPU_STATE_SHUTDOWN
) {
_CPU_SMP_Processor_event_receive();
state = cpu->state;
}
break;
case PER_CPU_STATE_UP:
while (
state != PER_CPU_STATE_REQUEST_START_MULTITASKING
&& state != PER_CPU_STATE_SHUTDOWN
) {
_CPU_SMP_Processor_event_receive();
state = cpu->state;
}
break;
default:
/* No need to wait */
break;
}
}
static Per_CPU_State _Per_CPU_State_get_next(
Per_CPU_State current_state,
Per_CPU_State new_state
)
{
switch ( current_state ) {
case PER_CPU_STATE_INITIAL:
switch ( new_state ) {
case PER_CPU_STATE_READY_TO_START_MULTITASKING:
case PER_CPU_STATE_SHUTDOWN:
/* Change is acceptable */
break;
default:
new_state = PER_CPU_STATE_SHUTDOWN;
break;
}
break;
case PER_CPU_STATE_READY_TO_START_MULTITASKING:
switch ( new_state ) {
case PER_CPU_STATE_REQUEST_START_MULTITASKING:
case PER_CPU_STATE_SHUTDOWN:
/* Change is acceptable */
break;
default:
new_state = PER_CPU_STATE_SHUTDOWN;
break;
}
break;
case PER_CPU_STATE_REQUEST_START_MULTITASKING:
switch ( new_state ) {
case PER_CPU_STATE_UP:
case PER_CPU_STATE_SHUTDOWN:
/* Change is acceptable */
break;
default:
new_state = PER_CPU_STATE_SHUTDOWN;
break;
}
break;
default:
new_state = PER_CPU_STATE_SHUTDOWN;
break;
}
return new_state;
}
void _Per_CPU_State_change(
Per_CPU_Control *cpu,
Per_CPU_State new_state
)
{
SMP_lock_Control *lock = &_Per_CPU_State_lock;
SMP_lock_Context lock_context;
Per_CPU_State next_state;
_Per_CPU_State_busy_wait( cpu, new_state );
_SMP_lock_ISR_disable_and_acquire( lock, &lock_context );
next_state = _Per_CPU_State_get_next( cpu->state, new_state );
cpu->state = next_state;
if ( next_state == PER_CPU_STATE_SHUTDOWN ) {
uint32_t cpu_max = rtems_configuration_get_maximum_processors();
uint32_t cpu_index;
for ( cpu_index = 0 ; cpu_index < cpu_max ; ++cpu_index ) {
Per_CPU_Control *cpu_other = _Per_CPU_Get_by_index( cpu_index );
if ( cpu_other != cpu ) {
switch ( cpu_other->state ) {
case PER_CPU_STATE_UP:
_SMP_Send_message( cpu_index, SMP_MESSAGE_SHUTDOWN );
break;
default:
/* Nothing to do */
break;
}
cpu_other->state = PER_CPU_STATE_SHUTDOWN;
}
}
}
_CPU_SMP_Processor_event_broadcast();
_SMP_lock_Release_and_ISR_enable( lock, &lock_context );
if (
next_state == PER_CPU_STATE_SHUTDOWN
&& new_state != PER_CPU_STATE_SHUTDOWN
) {
_SMP_Fatal( SMP_FATAL_SHUTDOWN );
}
}
#else
/*
* On single core systems, we can efficiently directly access a single
* statically allocated per cpu structure. And the fields are initialized
* as individual elements just like it has always been done.
*/
Per_CPU_Control_envelope _Per_CPU_Information[1];
#endif
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