mbed-os/hal/mbed_critical_section_api.c

66 lines
1.9 KiB
C

/* mbed Microcontroller Library
* Copyright (c) 2017 ARM Limited
*
* Licensed 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.
*/
#include "cmsis.h"
#include "hal/critical_section_api.h"
#include "platform/mbed_assert.h"
#include "platform/mbed_toolchain.h"
#include <stdbool.h>
static volatile bool critical_interrupts_enabled = false;
static bool are_interrupts_enabled(void)
{
#if defined(__CORTEX_A9)
return ((__get_CPSR() & 0x80) == 0);
#else
return ((__get_PRIMASK() & 0x1) == 0);
#endif
}
MBED_WEAK void hal_critical_section_enter(void)
{
critical_interrupts_enabled = are_interrupts_enabled();
#ifndef FEATURE_UVISOR
// If we are in a nested critical section and interrupts are still enabled
// something has gone wrong.
MBED_ASSERT(!are_interrupts_enabled());
#else
#warning "core_util_critical_section_enter needs fixing to work from unprivileged code"
#endif /* FEATURE_UVISOR */
__disable_irq();
}
MBED_WEAK void hal_critical_section_exit()
{
// FIXME
#ifndef FEATURE_UVISOR
// Interrupts must be disabled on invoking an exit from a critical section
MBED_ASSERT(!are_interrupts_enabled());
#else
#warning "core_util_critical_section_exit needs fixing to work from unprivileged code"
#endif /* FEATURE_UVISOR */
// Restore the IRQs to their state prior to entering the critical section
if (critical_interrupts_enabled == true) {
__enable_irq();
}
}