mbed_critical.c

00001 /*
00002  * Copyright (c) 2015-2019, ARM Limited, All Rights Reserved
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License"); you may
00006  * not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  * http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00013  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 
00018 /* Declare __STDC_LIMIT_MACROS so stdint.h defines UINT32_MAX when using C++ */
00019 #define __STDC_LIMIT_MACROS
00020 #include "hal/critical_section_api.h"
00021 
00022 #include "cmsis.h"
00023 #include "platform/mbed_assert.h"
00024 #include "platform/mbed_critical.h"
00025 
00026 static uint32_t critical_section_reentrancy_counter = 0;
00027 
00028 bool core_util_are_interrupts_enabled(void)
00029 {
00030 #if defined(__CORTEX_A9)
00031     return ((__get_CPSR() & 0x80) == 0);
00032 #else
00033     return ((__get_PRIMASK() & 0x1) == 0);
00034 #endif
00035 }
00036 
00037 bool core_util_is_isr_active(void)
00038 {
00039 #if defined(__CORTEX_A9)
00040     switch (__get_CPSR() & 0x1FU) {
00041         case CPSR_M_USR:
00042         case CPSR_M_SYS:
00043             return false;
00044         case CPSR_M_SVC:
00045         default:
00046             return true;
00047     }
00048 #else
00049     return (__get_IPSR() != 0U);
00050 #endif
00051 }
00052 
00053 bool core_util_in_critical_section(void)
00054 {
00055     return hal_in_critical_section();
00056 }
00057 
00058 void core_util_critical_section_enter(void)
00059 {
00060     hal_critical_section_enter();
00061 
00062     // If the reentrancy counter overflows something has gone badly wrong.
00063     MBED_ASSERT(critical_section_reentrancy_counter < UINT32_MAX);
00064 
00065     ++critical_section_reentrancy_counter;
00066 }
00067 
00068 void core_util_critical_section_exit(void)
00069 {
00070 
00071     // If critical_section_enter has not previously been called, do nothing
00072     if (critical_section_reentrancy_counter == 0) {
00073         return;
00074     }
00075 
00076     --critical_section_reentrancy_counter;
00077 
00078     if (critical_section_reentrancy_counter == 0) {
00079         hal_critical_section_exit();
00080     }
00081 }