nuttx/arch/arm/src/armv8-m/arm_doirq.c
ligd e2df52390a SMP: fix crash when switch to new task which is still running
Situation:

Assume we have 2 cpus, and busy run task0.

CPU0                                CPU1
task0 -> task1                      task2 -> task0
1. remove task0 form runninglist
2. take task1 as new tcb
3. add task0 to blocklist
4. clear spinlock
                                    4.1 remove task2 form runninglist
                                    4.2 take task0 as new tcb
                                    4.3 add task2 to blocklist
                                    4.4 use svc ISR swith to task0
                                    4.5 crash
5. use svc ISR swith to task1

Fix:
Move clear spinlock to the end of svc ISR

Signed-off-by: ligd <liguiding1@xiaomi.com>
2022-09-17 17:37:47 +09:00

97 lines
2.9 KiB
C

/****************************************************************************
* arch/arm/src/armv8-m/arm_doirq.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 <stdint.h>
#include <assert.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/board.h>
#include <arch/board/board.h>
#include "arm_internal.h"
/****************************************************************************
* Public Functions
****************************************************************************/
uint32_t *arm_doirq(int irq, uint32_t *regs)
{
board_autoled_on(LED_INIRQ);
#ifdef CONFIG_SUPPRESS_INTERRUPTS
PANIC();
#else
/* Nested interrupts are not supported in this implementation. If you
* want to implement nested interrupts, you would have to (1) change the
* way that CURRENT_REGS is handled and (2) the design associated with
* CONFIG_ARCH_INTERRUPTSTACK.
*/
/* Current regs non-zero indicates that we are processing an interrupt;
* CURRENT_REGS is also used to manage interrupt level context switches.
*/
if (CURRENT_REGS == NULL)
{
CURRENT_REGS = regs;
regs = NULL;
}
/* Acknowledge the interrupt */
arm_ack_irq(irq);
/* Deliver the IRQ */
irq_dispatch(irq, (uint32_t *)CURRENT_REGS);
/* If a context switch occurred while processing the interrupt then
* CURRENT_REGS may have change value. If we return any value different
* from the input regs, then the lower level will know that a context
* switch occurred during interrupt processing.
*/
if (regs == NULL)
{
/* Restore the cpu lock */
if (regs != CURRENT_REGS)
{
restore_critical_section();
regs = (uint32_t *)CURRENT_REGS;
}
/* Update the CURRENT_REGS to NULL. */
CURRENT_REGS = NULL;
}
#endif
board_autoled_off(LED_INIRQ);
return regs;
}