walnux/arch/arm/arm/arm_sigdeliver.c
Luchian Mihai 7335b36eca
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walnux: moveout
2025-11-04 19:15:10 +02:00

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C

/****************************************************************************
* arch/arm/src/arm/arm_sigdeliver.c
*
* SPDX-License-Identifier: Apache-2.0
*
* 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 <sched.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/board.h>
#include <arch/board/board.h>
#include "sched/sched.h"
#include "arm_internal.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: arm_sigdeliver
*
* Description:
* This is the a signal handling trampoline. When a signal action was
* posted. The task context was mucked with and forced to branch to this
* location with interrupts disabled.
*
****************************************************************************/
void arm_sigdeliver(void)
{
struct tcb_s *rtcb = this_task();
board_autoled_on(LED_SIGNAL);
sinfo("rtcb=%p sigdeliver=%p sigpendactionq.head=%p\n",
rtcb, rtcb->sigdeliver, rtcb->sigpendactionq.head);
DEBUGASSERT(rtcb->sigdeliver != NULL);
#ifndef CONFIG_SUPPRESS_INTERRUPTS
/* Then make sure that interrupts are enabled. Signal handlers must always
* run with interrupts enabled.
*/
up_irq_enable();
#endif
/* Deliver the signal */
(rtcb->sigdeliver)(rtcb);
/* Output any debug messages BEFORE restoring errno (because they may
* alter errno), then disable interrupts again and restore the original
* errno that is needed by the user logic (it is probably EINTR).
*/
sinfo("Resuming\n");
up_irq_save();
/* Modify the saved return state with the actual saved values in the
* TCB. This depends on the fact that nested signal handling is
* not supported. Therefore, these values will persist throughout the
* signal handling action.
*
* Keeping this data in the TCB resolves a security problem in protected
* and kernel mode: The regs[] array is visible on the user stack and
* could be modified by a hostile program.
*/
rtcb->sigdeliver = NULL; /* Allows next handler to be scheduled */
/* Then restore the correct state for this thread of execution. */
board_autoled_off(LED_SIGNAL);
rtcb->xcp.regs = rtcb->xcp.saved_regs;
arm_fullcontextrestore();
}