* arch/arm64/src/common/arm64_cpuidlestack.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <assert.h>
#include <nuttx/arch.h>
#include <nuttx/sched.h>
#include <nuttx/tls.h>
#include "arm64_smp.h"
#include "arm64_internal.h"
* Pre-processor Definitions
****************************************************************************/
#define STACK_ISALIGNED(a) ((uintptr_t)(a) & ~STACK_ALIGN_MASK)
* Private Data
****************************************************************************/
* Public Functions
****************************************************************************/
* Name: up_cpu_idlestack
*
* Description:
* Allocate a stack for the CPU[n] IDLE task (n > 0) if appropriate and
* setup up stack-related information in the IDLE task's TCB. This
* function is always called before up_cpu_start(). This function is
* only called for the CPU's initial IDLE task; up_create_task is used for
* all normal tasks, pthreads, and kernel threads for all CPUs.
*
* The initial IDLE task is a special case because the CPUs can be started
* in different ways in different environments:
*
* 1. The CPU may already have been started and waiting in a low power
* state for up_cpu_start(). In this case, the IDLE thread's stack
* has already been allocated and is already in use. Here
* up_cpu_idlestack() only has to provide information about the
* already allocated stack.
*
* 2. The CPU may be disabled but started when up_cpu_start() is called.
* In this case, a new stack will need to be created for the IDLE
* thread and this function is then equivalent to:
*
* return up_create_stack(tcb, stack_size, TCB_FLAG_TTYPE_KERNEL);
*
* The following TCB fields must be initialized by this function:
*
* - adj_stack_size: Stack size after adjustment for hardware, processor,
* etc. This value is retained only for debug purposes.
* - stack_alloc_ptr: Pointer to allocated stack
* - stack_base_ptr: Adjusted stack base pointer after the TLS Data and
* Arguments has been removed from the stack allocation.
*
* Input Parameters:
* - cpu: CPU index that indicates which CPU the IDLE task is
* being created for.
* - tcb: The TCB of new CPU IDLE task
* - stack_size: The requested stack size for the IDLE task. At least
* this much must be allocated. This should be
* CONFIG_IDLETHREAD_STACKSIZE.
*
****************************************************************************/
int up_cpu_idlestack(int cpu, struct tcb_s *tcb, size_t stack_size)
{
DEBUGASSERT(cpu >= 0 && cpu < CONFIG_NCPUS && tcb != NULL);
tcb->adj_stack_size = stack_size;
tcb->stack_alloc_ptr = (void *)g_cpu_idlestackalloc[cpu];
tcb->stack_base_ptr = tcb->stack_alloc_ptr;
return OK;
}